96-30733. Health Standards for Occupational Noise Exposure  

  • [Federal Register Volume 61, Number 243 (Tuesday, December 17, 1996)]
    [Proposed Rules]
    [Pages 66348-66469]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 96-30733]
    
    
    
    [[Page 66347]]
    
    _______________________________________________________________________
    
    Part II
    
    
    
    
    
    Department of Labor
    
    
    
    
    
    _______________________________________________________________________
    
    
    
    Mine Safety and Health Administration
    
    
    
    _______________________________________________________________________
    
    
    
    30 CFR Parts 56, 57, 62, 70 and 71
    
    
    
    Health Standards for Occupational Noise Exposure in Coal, Metal, and 
    Nonmetal Mines; Proposed Rule
    
    Federal Register / Vol. 61, No. 243 / Tuesday, December 17, 1996 / 
    Proposed Rules
    
    [[Page 66348]]
    
    
    
    DEPARTMENT OF LABOR
    
    Mine Safety and Health Administration
    
    30 CFR Parts 56, 57, 62, 70 and 71
    
    RIN 1219-AA53
    
    
    Health Standards for Occupational Noise Exposure
    
    AGENCY: Mine Safety and Health Administration (MSHA), Labor.
    
    ACTION: Proposed rule.
    
    -----------------------------------------------------------------------
    
    SUMMARY: This proposed rule would replace MSHA's existing standards for 
    occupational noise exposure in coal mines and in metal and nonmetal 
    mines with a single new standard applicable to all mines.
        This action is part of the Agency's ongoing review of its safety 
    and health standards. The review found that the Agency's existing noise 
    standards, which had been promulgated more than 20 years ago, are 
    inadequate to prevent the occurrence of occupational noise-induced 
    hearing loss (NIHL) among miners. There remains a significant risk to 
    miners of material impairment of health from workplace exposure to 
    noise over a working lifetime. The risk becomes significant when 
    exposure exceeds an 8-hour time-weighted average of 85 dBA.
    
    DATES: Comments must be received on or before February 18, 1997. Submit 
    written comments on the information collection requirements by February 
    18, 1997.
    
    ADDRESSES: Comments on the proposed rule may be transmitted by 
    electronic mail, fax, or mail. Comments by electronic mail must be 
    clearly identified as such and sent to this e-mail address: 
    noise@msha.gov. Comments by fax must be clearly identified as such and 
    sent to: Mine Safety and Health Administration, Office of Standards, 
    Regulations, and Variances, 703-235-5551. Send mail comments to: Mine 
    Safety and Health Administration, Office of Standards, Regulations, and 
    Variances, Room 631, 4015 Wilson Boulevard, Arlington, VA 22203-1984. 
    Interested persons are encouraged to supplement written comments with 
    computer files or disks; please contact the Agency with any questions 
    about format. Written comments on the information collection 
    requirements may be submitted directly to the Office of Information and 
    Regulatory Affairs, OMB New Executive Office Building, 725 17th Street, 
    NW., Rm. 10235, Washington, D.C. 20503, Attn: Desk Officer for MSHA.
    
    FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director; MSHA; 
    Office of Standards, Regulations, and Variances; 703-235-1910.
    
    SUPPLEMENTARY INFORMATION:
    
    Comprehensive Summary
    
        The proposal would retain the existing permissible exposure level 
    (PEL) but establish a new ``action level''. The action level would be 
    an 8-hour time-weighted average of 85 dBA; the PEL would remain an 8-
    hour time-weighted average of 90 dBA.
        Whenever a miner's noise exposure exceeds the action level, the 
    miner would receive special training in noise protection.
        When the miner's noise exposure exceeds the action level, but is 
    below the PEL, the operator would be required to make annual 
    audiometric (hearing) examinations available to the miner through 
    enrollment in a hearing conservation program, and to provide properly 
    fitted hearing protection in three circumstances--before the initial 
    hearing examination, if a significant threshold shift in hearing acuity 
    is detected, and at any other time upon miner request. If it will take 
    more than 6 months for the initial examination because of the need to 
    wait for a mobile test van, or a significant threshold shift in hearing 
    acuity is detected, the operator would also be required to ensure the 
    miner uses the provided hearing protection.
        If a miner's exposure exceeds the PEL, the proposal would require 
    that the mine operator use all engineering and administrative controls 
    which it is feasible for that mine operator to utilize to reduce noise 
    to the PEL. The proper combination of engineering and administrative 
    controls would be left to the discretion of the mine operator.
        Should the use of all feasible engineering and administrative 
    controls not reduce a miner's noise exposure to the PEL, the operator 
    would have to use those controls to lower exposure to as close to the 
    PEL as is feasible. In addition, the operator would have to provide any 
    such miner properly fitted hearing protection, ensure the miner uses 
    such protection, and ensure the miner takes the annual audiometric 
    examinations. Should a miner's exposure exceed an 8-hour time-weighted 
    average of 105 dBA, the operator must ensure the miner is provided and 
    uses both a plug and a muff type protector.
        MSHA recognizes that successful implementation of these new uniform 
    health rules will require training of MSHA personnel and guidance to 
    miners and mine operators, particularly small mine operators. 
    Accordingly, the Agency proposes that the final rule take effect one 
    year after the date of publication of the final rule, and solicits 
    comments on whether a phased-in approach would permit some elements of 
    the new rule to be implemented more quickly.
        The Supplementary Information accompanying this notice is detailed. 
    Accordingly, to facilitate review and comment by the mining community, 
    this material begins with questions and answers summarizing key points 
    about the proposal. Included are two charts comparing the main features 
    of the proposal to existing standards in the mining industry and those 
    applicable to other industries under the Occupational Safety and Health 
    Act. Also included are MSHA's estimates of the impacts of the proposal 
    from the Agency's preliminary Regulatory Impact Analysis (RIA), copies 
    of which are available from the Agency.
    
    I. Questions and Answers, Required Notices, and History
    
    (A) Questions and Answers About Key Features of this Proposal
    
    (1) What Are the Key Features of This Proposal?
        MSHA has developed a proposal that it estimates can reduce by two-
    thirds the number of miners currently projected to suffer a material 
    impairment of their hearing--but which it estimates can be implemented 
    at a cost of less than $9 million to the mining industry as a whole.
        The focus of the proposal is on the use of the most effective means 
    to control noise--engineering controls to eliminate the noise, or 
    administrative controls (e.g. rotating miner duties) to minimize noise 
    exposure--whenever feasible.
        Specifically, the proposal requires that an operator use all 
    feasible engineering or administrative controls to reduce noise to the 
    PEL--a TWA8 of 90 dBA. While MSHA has determined there is a 
    significant risk of harm at a TWA8 of 85 dBA, the Agency believes 
    that it may not be feasible at this time for the mining industry to 
    control noise to this level using engineering and administrative 
    controls.
        The proposal would require that steps be taken when noise exceeds a 
    TWA8 of 85 dBA, the ``action level'', to prevent hearing loss. 
    Operators would have to provide special instruction in noise, make 
    annual hearing examinations available, and provide properly fitted 
    hearing protection--before the initial examination, if a significant 
    threshold shift in hearing acuity is detected, and at any other time 
    upon a miner's
    
    [[Page 66349]]
    
    request. If it will take more than 6 months to take the initial 
    examination because of the need to wait for a mobile test van, or if a 
    significant threshold shift is detected, an operator would also be 
    required to ensure that the miner uses the hearing protection.
        The proposal also provides for supplemental protection in those 
    cases in which individual operators are unable to reduce noise to the 
    PEL through the use of all feasible engineering or administrative 
    controls. The operator must ensure any miner so exposed takes the 
    annual hearing examinations, must provide properly fitted hearing 
    protection to all miners so exposed, and must ensure the hearing 
    protection is used by all miners so exposed.
        The focus on engineering and administrative controls would 
    significantly change the way noise is addressed in the coal mining 
    industry. Currently, hearing protectors generally are allowed when a 
    coal miner's noise exposure exceeds the PEL. The proposal would require 
    a coal mine operator to use all feasible engineering and administrative 
    controls to reduce exposure to the PEL--the practice currently required 
    in the rest of the mining industry. MSHA estimates that this change 
    alone can prevent 3 out of every 5 impairments projected to occur due 
    to occupational noise exposure in the coal mining industry.
        While this change would cost the coal mining industry more money 
    for implementation of engineering controls, MSHA estimates these costs 
    would be significantly offset by the paperwork savings the coal mining 
    industry will accrue under the proposal. In particular, MSHA is 
    proposing to replace the costly, paperwork-intensive requirements for 
    biannual coal miner noise exposure surveys, supplemental noise surveys, 
    calibration reports, survey reports, and survey certifications with a 
    performance-oriented requirement that mine operators establish a 
    monitoring program that effectively evaluates miner exposures. MSHA 
    believes the existing requirements have not been effective.
        Other parts of the proposal would change current practices 
    throughout the mining industry. No actions are currently required if 
    noise exposures are below the PEL. Moreover, the proposal requires, for 
    the first time, certain explicit protections if an operator cannot 
    feasibly reduce noise exposures to the PEL through the use of all 
    feasible engineering and administrative controls.
        MSHA's proposal also incorporates revisions warranted by our 
    increased understanding of the effects of noise, to the extent that the 
    Agency determined such changes would be feasible for the mining 
    industry to implement. For example, to reflect that exposure to sound 
    levels above 80 dBA is now generally recognized as harmful, the 
    proposal would include exposure to such sound levels in determining a 
    miner's noise dose. Such adjustment will result in more miners than at 
    present being determined to have noise exposures over the PEL, but the 
    Agency has determined that the industry can feasibly accommodate this 
    change.
    (2) Do I Need To Read This Entire Notice To Understand the Proposal?
        The Agency hopes these questions and answers will provide the 
    information most of the mining community will want. Nevertheless, MSHA 
    is accompanying publication of this proposed rule with a detailed 
    discussion of the information it has considered in developing the 
    proposal. That way, those interested in a particular topic can have the 
    benefit of the Agency's thinking in developing their comments.
        The information is divided into five parts. Part I includes a 
    review of the projected impacts of the proposal, including benefits, 
    costs and paperwork, taken from the Agency's preliminary RIA. Part II 
    is the Agency's analysis of the current risks to miners from 
    occupational noise exposure. Part III is a section-by-section 
    discussion of the elements of the proposal. Part IV is an analysis of 
    the technological and economic feasibility of the proposal and of key 
    alternatives considered by the Agency. Part V is a complete list of 
    publications referenced by the Agency.
    (3) What Are the Projected Impacts of the Proposed Rule?
        The estimated benefits and costs and paperwork requirements of the 
    proposed rule are summarized in the following table, ``Summary of Key 
    Impacts of MSHA's Noise Proposal,'' followed by a brief explanation. 
    The Agency's estimates, and a complete description of the methodology 
    used to obtain them, are contained in the Agency's preliminary RIA, a 
    copy of which can be obtained from the Agency.
    
                                    Summary of Key Impacts of MSHA's Noise Proposal *                               
    ----------------------------------------------------------------------------------------------------------------
                                                                    Coal          Metal/nonmetal       All mining   
    ----------------------------------------------------------------------------------------------------------------
    Benefits:                                                                                                       
        % hearing impairments avoided......................                 81                 57                 67
        # miners saved from hearing impairment.............             15,300             15,300             30,600
    Annual costs (in millions of dollars)..................               $0.3                 $8               $8.3
    Paperwork burden hours added/saved.....................           (88,740)             73,755          (14,985) 
    ----------------------------------------------------------------------------------------------------------------
    * Rounded.                                                                                                      
    
        The analysis of benefits compares the number of miners who are 
    projected to incur a material impairment of their hearing under the 
    current rule with the number of miners who are projected to incur such 
    an impairment under the proposed rule. Overall for the mining 
    community, the proposal would reduce the risk of material impairment by 
    67%. More than 30,000 miners otherwise expected to develop a material 
    impairment would be spared.
        As displayed in the chart entitled ``Benefits of MSHA Noise 
    Proposal in Saving Miners From Hearing Impairment,'' the most 
    significant benefits are expected in the coal sector. Engineering and 
    administrative controls are expected to significantly reduce noise 
    exposures above the PEL. A significant benefit also accrues from the 
    establishment of an action level: based on the assumption that most 
    employees exposed to noise between the action level and the PEL will 
    elect to use hearing protection for the first time at such levels. 
    While the metal and nonmetal mining industry already uses engineering 
    controls above the PEL, additional benefits are anticipated in this 
    regard; primarily because the change in the way noise dose would be 
    measured under the proposal would require the use of engineering and 
    administrative controls in more cases than at present. Like coal, a 
    benefit in
    
    [[Page 66350]]
    
    this sector is anticipated from the establishment of an action level.
        As indicated by this chart, MSHA projects that even after 
    implementation of the proposal some miners will continue to develop a 
    material impairment of hearing. This is of serious concern to the 
    Agency. The Agency believes, however, that the mining industry may not 
    be able at this time to feasibly take actions which would eliminate the 
    remaining risk (see response to Questions 9 and 13 on this point). MSHA 
    is seeking comments on this issue.
    
    Benefits of MSHA Noise Proposal in Saving Miners From Hearing Impairment
    ------------------------------------------------------------------------
                                                                    Miners  
    ------------------------------------------------------------------------
    Coal:                                                                   
        Current expected impairment..  15% of miners...........       18,947
        Saved by eng/admin controls..  58% of projected               11,072
                                        impairment.                         
        Saved by hearing protectors..  22% of projected                4,232
                                        impairment.                         
        Saved by proposal............  81% of projected               15,304
                                        impairment.                         
        Remaining expected impairment  3% of miners............        3,643
    Metal and Nonmetal:                                                     
        Current expected impairment..  13% of miners...........       26,977
        Saved by eng/admin controls..  11% of projected                2,693
                                        impairment.                         
        Saved by hearing protectors..  46% of projected               12,320
                                        impairment.                         
        Saved by proposal............  57% of projected               15,283
                                        impairment.                         
        Remaining expected impairment  6% of miners............       11,694
    Mining Industry as a Whole:                                             
        Current expected impairment..  14% of miners...........       45,924
        Saved by eng/admin controls..  31% of projected               14,035
                                        impairment.                         
        Saved by hearing protectors..  36% of projected               16,552
                                        impairment.                         
        Saved by proposal............  67% of projected               30,587
                                        impairment.                         
        Remaining expected impairment  5% of miners............       15,377
    ------------------------------------------------------------------------
    
        MSHA's estimates of cost follow a standard approach in which 
    initial costs of compliance (like equipment purchase costs) are 
    amortized over ten years at seven percent and added to costs that recur 
    each year. The assumptions on what controls would be needed, how many 
    hours have to be spent on particular tasks, and the costs of the 
    personnel performing various tasks are set forth in detail in the 
    Agency's preliminary RIA.
        MSHA estimates that the proposed rule would increase the mining 
    industry's costs by approximately $8.3 million annually for the first 
    10 years. MSHA estimates the proposed rule will cost the coal mining 
    industry about $300,000 a year; because while there will be additional 
    costs under the proposal, they will be significantly offset by the 
    elimination of the requirements for biannual noise surveys of coal 
    miners. Costs to the metal and nonmetal industry would rise by about $8 
    million annually.
        The most costly aspect of the proposed rule would be the provision 
    of audiometric examinations--about $3.6 million, with about $2 million 
    of that borne by the metal and nonmetal mining industry. The provision 
    of engineering controls is estimated to cost about $3.5 million, with 
    about $2.2 million of this borne by the coal mining industry--which 
    would no longer be permitted, as at present, to substitute hearing 
    protectors for engineering or administrative controls. MSHA's costing 
    assumptions are described in its preliminary RIA; comments on this 
    methodology are being solicited.
        The table entitled ``Cost Impacts of MSHA Noise Proposal'' 
    summarizes the net annual costs of the proposal's requirements. An 
    explanation of the requirements is included in the questions and 
    answers that follow.
    
                                           Cost Impacts of MSHA Noise Proposal                                      
    ----------------------------------------------------------------------------------------------------------------
                                  Task                                  Total cost       M/NM cost       Coal cost  
    ----------------------------------------------------------------------------------------------------------------
    Engineering Controls............................................      $3,475,700      $1,289,000      $2,186,700
    Dose Determination..............................................     (1,928,550)       1,734,895     (3,663,445)
    Notification....................................................          45,910          28,085          17,825
    Record of Noise Surveys, et al..................................     (1,653,565)  ..............     (1,653,565)
    Administrative Controls.........................................          16,595           6,580          10,015
    HPDs (provide, selection, fit)..................................         926,710         792,560         134,150
    Training........................................................       1,834,560       1,071,140         763,420
    Audiograms (base, annual); notice to miners.....................       3,574,030       1,964,970       1,609,060
    Audiometric Test Procedures.....................................         195,835         113,835          82,000
    Evaluation of Audiogram.........................................         892,215         492,215         400,000
    Follow-up Evaluation............................................         145,780          78,865          66,915
    Follow-up Corrective Measures...................................          99,440          52,455          46,985
    Notification of Results.........................................         138,710          74,340          54,370
    Access to Records...............................................          23,710          18,865           4,845
    Transfer of Records.............................................           5,040           2,950           2,090
    Contractors.....................................................         541,640         316,320         225,320
                                                                     -----------------------------------------------
          Total.....................................................       8,323,760       8,037,075         286,685
    ----------------------------------------------------------------------------------------------------------------
    
        MSHA's estimates of paperwork burden hours reflect the requirements 
    and definitions in the Paperwork Reduction Act. Overall, the proposal 
    would decrease paperwork requirements in the mining industry by about 
    14,985 burden hours. This reflects a savings to the coal mining 
    industry of 88,740 burden hours, as a result of a proposal to eliminate
    
    [[Page 66351]]
    
    existing requirements for biannual surveys of coal miners and other 
    various reports. The metal and nonmetal mining sector would have a net 
    increase of about 73,755 burden hours. The chart entitled ``Paperwork 
    Impacts of MSHA Noise Proposal'' summarizes the projected paperwork 
    burdens.
    
                                        Paperwork Impacts of MSHA Noise Proposal                                    
    ----------------------------------------------------------------------------------------------------------------
                                         Paperwork requirement and associated                                       
                  Section                               tasks                      Coal         M/NM        Total   
    ----------------------------------------------------------------------------------------------------------------
    62.120............................  Evaluate miners' noise exposure;         (140,545)        5,295    (135,250)
                                         notify miner of overexposure,                                              
                                         prepare and post administrative                                            
                                         controls; give miners copy of                                              
                                         administrative controls.                                                   
    62.130............................  Prepare and file a training                  4,000        6,270       10,270
                                         certification.                                                             
    62.140............................  Perform audiograms, notify miners to        30,655       39,275       69,930
                                         appear for testing and need to avoid                                       
                                         high noise.                                                                
    62.150............................  Compile an audiometric test record,          3,930        5,245        9,175
                                         obtain a certification.                                                    
    62.160............................  Provide information and audiometric          9,340       12,015       21,455
                                         test record, perform audiometric                                           
                                         retests.                                                                   
    62.170............................  Perform audiometric evaluations and            475          570        1,045
                                         follow-up evaluations.                                                     
    62.180............................  Prepare a training certification for           335          365          700
                                         retrained miners, review                                                   
                                         effectiveness of engineering and                                           
                                         administrative controls.                                                   
    62.190............................  Inform miner of test results, inform         2,715        3,585        6,300
                                         miner of STS.                                                              
    62.200............................  Provide access to records............          255        1,000        1,255
    62.210............................  Transfer records.....................          100          135          235
    All...............................  (any discrepancies due to rounding)..     (88,740)       73,755     (14,985)
    ----------------------------------------------------------------------------------------------------------------
    
    (4) What Special Consideration Did MSHA Give to Alternatives for the 
    Smallest Mines?
        MSHA estimates that as a result of this proposal, metal and 
    nonmetal mines with less than 20 miners would incur an average cost 
    increase of about $500 per year in annual costs and annualized first 
    year costs. Coal mines with less than 20 miners would have an average 
    savings per mine of about $30, reflecting the elimination of the 
    numerous survey and paperwork requirements in the current noise rules 
    for the coal sector.
        MSHA compared the proposed costs for small mines in each sector to 
    the estimated revenues and profits for small mines in each sector. MSHA 
    did this at various size levels. In each case, the costs as a 
    percentage of revenue are less than 1%, and the costs do not appear to 
    have any appreciable impact on profits. Accordingly, for the purposes 
    of the Regulatory Flexibility Act, MSHA has certified that the proposed 
    rule does not have a significant economic impact on a substantial 
    number of small entities.
        The limited impacts on small mines reflect decisions by MSHA not to 
    propose more costly regulatory alternatives. In considering regulatory 
    alternatives for small mines, MSHA must observe the requirements of its 
    authorizing statute. Section 101(a)(6)(A) of the Mine Act requires the 
    Secretary to set standards which most adequately assure, on the basis 
    of the best available evidence, that no miner will suffer material 
    impairment of health over his/her working lifetime. In addition, the 
    Mine Act requires that the Secretary, when promulgating mandatory 
    standards pertaining to toxic materials or harmful physical agents, 
    consider other factors, such as the latest scientific data in the 
    field, the feasibility of the standard and experience gained under the 
    Act and other health and safety laws. Thus, the Mine Act requires that 
    the Secretary, in promulgating a standard, attain the highest degree of 
    health and safety protection for the miner, based on the ``best 
    available evidence,'' with feasibility a consideration.
        As a result of this requirement, MSHA seriously considered two 
    alternatives that would have significantly increased costs for small 
    mine operators--lowering the PEL to a TWA8 of 85 dBA, and lowering 
    the exchange rate to 3 dB. In both cases, the evidence in favor of 
    these approaches was strong. But in both cases, MSHA has tentatively 
    concluded that it may not be feasible for the mining industry to 
    accomplish these more protective approaches. The impact of these 
    approaches on small mine operators was an important consideration in 
    this regard.
        Part IV of this preamble contains a full discussion of MSHA's 
    preliminary conclusions about these alternatives. The graph labeled 
    ``Effect of Alternative Exchange Rates and PELs on Allowable Exposure 
    Times at Various Decibel Levels'' provides an indication of what the 
    Agency's decisions in this regard mean in practice.
    
    BILLING CODE 4510-43-P
    
    [[Page 66352]]
    
    [GRAPHIC] [TIFF OMITTED] TP17DE96.000
    
    
    BILLING CODE 4510-43-C
    
        In accordance with the Small Business Regulatory Enforcement and 
    Fairness Act (SBREFA), MSHA is taking actions to minimize the 
    compliance burden on small mines. The proposed effective date of the 
    rule would be a year after final promulgation, to provide adequate time 
    for small mines to achieve compliance. MSHA will also mail a copy of 
    the proposed rule to every mine operator which primarily benefits small 
    mine operators. MSHA is committed to writing the final rule in plain 
    English so it can be readily understood by miners and mine operators. 
    The Agency has committed itself to issuance of a compliance guide, and 
    is inviting comment on whether compliance workshops or other such 
    approaches would be valuable. (These proposed actions are discussed in 
    more detail in other Questions and Answers.)
        The approximately 350 small sand and gravel or crushed stone 
    operations run by State, local and tribal governments may also be 
    interested in MSHA's analysis on the impacts of the proposed rule on 
    such entities. Such an analysis is required by the Unfunded Mandates 
    Reform Act of 1995. Like other small metal and nonmetal mines, their 
    costs for prevention of hearing loss are expected to average about $500 
    per year. Benefits to these governmental entities include fewer hearing 
    impairments and reduced workers' compensation costs.
    (5) Why Is the Proposed Rule Needed?
        MSHA has concluded that the existing rules to protect miners from 
    workplace noise exposure must be revised because current noise 
    exposures continue to create a significant risk of material impairment 
    of health to miners. MSHA estimates that 14% of U.S. miners--about 
    46,000 of them--can be expected under current exposure conditions to 
    develop a material impairment of hearing during a working lifetime. The 
    figures are 15% (19,000) of U.S. coal miners and 13% (27,000) of U.S. 
    metal and nonmetal miners.
        Generally, prolonged exposure to noise over a period of several 
    years causes permanent damage to the auditory nerve and/or its sensory 
    components: the higher the noise exposure the more rapid the loss. The 
    loss may be so gradual, however, that a person may not realize that he 
    or she is becoming impaired until a substantial amount of hearing is 
    lost. This damage, known as noise-induced hearing loss or NIHL, is 
    irreversible, and makes it difficult to hear as well as understand 
    speech. In addition to the personal and social costs of hearing loss, 
    the loss of the ability to understand speech can have a significant 
    impact on miner safety which is highly dependent upon good 
    communication.
        The Agency has carefully analyzed the risk miners currently face of 
    incurring such harm. What follows is a short summary of MSHA's risk 
    analysis (the complete analysis is presented as part II of the 
    Supplemental Information accompanying this notice).
        First, the Agency considered the various definitions of impairment 
    used in the risk analyses in the literature. Three definitions of 
    impairment have been widely recognized within the scientific community 
    as useful for the purposes of assessing risk. All three focus on the 
    risks of acquiring a 25 dB hearing ``level''--the deviation from 
    audiometric zero. The three accepted approaches differ in that they 
    examine hearing acuity at a different set of frequencies. For the 
    purpose of its analysis, MSHA chose the approach that measures hearing 
    acuity at those frequencies most relevant to the ability to understand 
    human speech. This is the approach developed in 1972 by the National 
    Institute for Occupational Safety and Health (NIOSH) and subsequently 
    used by the Occupational Safety and Health Administration
    
    [[Page 66353]]
    
    (OSHA): a 25 dB hearing level at 1000, 2000 and 3000 Hz. The Agency is 
    aware that NIOSH is now considering a revised approach that would 
    include hearing acuity at 4000 Hz, but believes it is inappropriate to 
    utilize that approach until peer review has validated its utility.
        Next, the Agency reviewed the major studies on the level of risk at 
    different noise exposures. The data consistently indicate that the risk 
    of developing a material impairment of hearing, as a result of a 
    working lifetime of occupational exposure, becomes significant when 
    workplace noise exposures exceed an eight-hour time-weighted average 
    (TWA8) of 85 dBA. The table entitled ``Excess Risk Estimates'' 
    presents estimates by NIOSH of how the excess risk of developing a 
    material impairment (using its 1972 definition) varies with exposure 
    over a working lifetime.
    
                                                  Excess Risk Estimates                                             
    ----------------------------------------------------------------------------------------------------------------
                                                                                                                    
    ----------------------------------------------------------------------------------------------------------------
    Exposure (TWA8).............          <80 80-84.9="" 85-89.9="" 90-94.9="" 95-99.9="">1
                                                                                                                 00 
    Excess Risk.................            0            3%           15%           29%           43%           54% 
    ----------------------------------------------------------------------------------------------------------------
    
        MSHA also reviewed a large body of data on the effects of varying 
    industrial noise exposures on worker hearing. These studies are 
    supportive of the same conclusion. MSHA refined its picture of what 
    occurs at lower sound levels by reviewing a number of other studies, 
    particularly those of workers in other countries.
        To confirm the magnitude of the risks of NIHL among miners, MSHA 
    asked NIOSH to examine a body of audiometric data collected over the 
    years tracking hearing acuity among coal miners. The analysis (Franks, 
    1996) supports the data from the risk studies. It indicates that 90% of 
    these miners have a hearing impairment by age 50 as compared with only 
    10% of the general population. Further, Franks stated that miners, 
    after working 20 to 30 years, could find themselves in life-threatening 
    situations because safety signals and ``roof talk'' could go unheard. 
    (For the purposes of the analysis, NIOSH used a definition of hearing 
    impairment including losses at 4000 Hz; MSHA conducted its own analysis 
    of the data without the 4000 Hz, and the results are generally 
    consistent with those of NIOSH).
        MSHA also examined other sources of data that might provide direct 
    confirmation of the risks of hearing loss to miners--comments received 
    in response to the Agency's Advance Notice of Proposed Rulemaking 
    (ANPRM), (December 4, 1989, 54 FR 50209), the reports of hearing loss 
    provided to the Agency by mine operators pursuant to 30 CFR part 50, 
    and workers' compensation data. In each case, the available data are 
    too limited to draw any conclusions. The Agency is requesting the 
    public to provide further information along these lines.
        To develop a profile of the mining population at risk, MSHA began 
    by gathering information on noise exposures in the U.S. mining 
    industry.
        Current exposures appear to be gradually declining in the metal and 
    nonmetal industry, where engineering or administrative controls are the 
    primary means of miner protection against NIHL. But the data indicate 
    that all sectors of the mining industry continue to have a significant 
    number of overexposures.
        Charts II-9 and II-10 display exposure trends based on inspector 
    samples. Only those samples that exceed the PEL are displayed. For 
    1995, 14.4% of samples from the metal and nonmetal mining industry, and 
    22.5% of samples from the coal industry, exceeded the PEL. (Because 
    they are 3-D graphs, the data points sometimes look lower than they 
    are; the actual data points can be found in part II, Tables II-9 and 
    II-10.)
    
    BILLING CODE 4510-43-P
    [GRAPHIC] [TIFF OMITTED] TP17DE96.001
    
    
    BILLING CODE 4510-43-C
    
        These figures actually understate truly harmful exposures because 
    the samples were taken in a way that did not count any exposures to 
    sound levels below 90 dBA. As discussed herein (see Question 9), MSHA 
    has concluded that exposures to sound levels above 80 dBA are harmful. 
    Accordingly, to get a better picture of present harmful miner 
    exposures, MSHA examined the results of a special survey taking 
    thousands of
    
    [[Page 66354]]
    
    samples that included sound levels as low as 80 dBA. The results 
    indicate that 36.8% of coal samples, and 26.9% of the metal and 
    nonmetal samples would exceed the PEL if the lower, but still harmful, 
    sound levels are counted in the dose measurement.
        To derive a risk profile of miners, the Agency utilized the 
    exposure data from the survey and the excess risk estimates. (The 
    methodology for developing the miner risk profile is explained in 
    detail in the Agency's preliminary RIA. Among other adjustments to the 
    sample data, MSHA assumed coal miners were currently receiving some 
    protection from hearing protectors; as a result, the estimates of 
    miners at excess risk are lower than might be suggested by the 
    foregoing figures.) Based on its analysis, MSHA estimates that 14% of 
    U.S. miners--about 46,000 miners--can be expected under current 
    exposure conditions to develop a material impairment of hearing of 
    handicapping or disabling proportions during a working lifetime. The 
    figures are 15% (19,000) of U.S. coal miners as a group and 13% 
    (27,000) of U.S. metal and nonmetal miners.
        The Agency is interested in receiving additional data with respect 
    to the risks of noise exposure to workers and to the mining population 
    in particular, as well as comments on its risk methodology and 
    analysis.
    (6) Why Proceed Without Waiting for NIOSH To Issue a New Criteria 
    Document on Noise Exposure?
        As MSHA was preparing this notice for publication, the National 
    Institute for Occupational Safety and Health (NIOSH) released for peer 
    review a draft criteria document for occupational noise exposure to 
    update the one issued in 1972.
        A summary of that draft, prepared and released by NIOSH, is 
    included in the discussion of the rulemaking history in the 
    Supplementary Information accompanying this notice. NIOSH is 
    considering whether the evidence on noise since 1972 warrants a change 
    in its recommendations. In some cases NIOSH is considering reiterating 
    its prior recommendations, and in other cases it is considering 
    changing its recommendations.
        MSHA has determined that it would not be appropriate to delay 
    publication of this proposed rule to await the possible issuance of a 
    new NIOSH criteria document. The NIOSH draft is still being peer 
    reviewed, and MSHA does not believe it would be appropriate to delay 
    acting based upon the uncertain timing of the document's redrafting and 
    release. Moreover, many of the issues covered in the NIOSH draft have 
    been considered by MSHA, as part of the Agency's review of all the 
    latest scientific information on noise.
        Should a new criteria document be issued before MSHA promulgates a 
    final rule, it will of course consider the NIOSH recommendations. The 
    summary of the NIOSH draft included in this notice should provide ample 
    notice to the mining community of the position NIOSH may take in a new 
    criteria document.
    (7) What Mines Are Covered by the Proposal?
        The proposal would apply one set of rules uniformly to all mines. 
    Those who responded to MSHA's ANPRM generally agreed that consolidation 
    and simplification of multiple standards into one rule may help to 
    facilitate understanding of, and thus compliance with, the regulatory 
    requirements for controlling noise exposures.
    (8) Are There Special Definitions Applicable?
        To help mine operators and miners, the proposed rule would include 
    definitions of some technical terms universally used in noise 
    measurement. But the proposed rule also includes some terms used in a 
    way that differs from usage in certain other contexts--e.g., under the 
    OSHA standard.
        In particular, MSHA is proposing a non-standard use of the term 
    ``hearing conservation program'' or ``HCP.'' Most hearing conservation 
    programs include provision for hearing examinations, training and the 
    use of hearing protectors. Since audiograms would be new for the mining 
    industry, unlike the other components, the Agency thought it might be 
    less confusing to treat the components separately. Accordingly, under 
    the MSHA proposal, hearing protector and training requirements are 
    established independently, and a ``hearing conservation program'' is 
    defined as a generic reference to those sections of the proposal that 
    set forth the requirements for an audiometric testing program.
    (9) How Is a Miner's Noise Dose To Be Determined Under the Proposal?
        The proposal sets forth a formula for dose computation, which is to 
    be measured over a full shift, which corresponds to the readouts of 
    most currently used personal noise dosimeters.
        The proposal would continue the use of a 5-dB exchange rate. The 
    exchange rate is a measure of how quickly the dose of noise doubles. 
    Accordingly, the measure is the rate determining how much a miner's 
    exposure must be limited to compensate for increasing dose. Using the 
    5-dB exchange rate, the exposure time permitted at a sound level of 90 
    dBA is half that permitted at a sound level of 85 dBA--a miner gets the 
    same noise dose in 4 hours at 90 dBA as at 8 hours at 85 dBA.
        The Agency gave serious consideration to changing the exchange rate 
    from 5 dB to 3 dB, and is specifically seeking comment on this 
    important matter. There is a consensus in the recent literature that 
    noise dose actually doubles more quickly than measured by the 5-dB 
    rate; the consensus is for an exchange rate of 3 dB. Moreover, the 
    current 5-dB exchange rate incorporates an assumption that there is 
    significant time for hearing to recover from high sound levels. MSHA 
    has concluded that noise exposure under mining conditions does not 
    warrant such an assumption. A 3-dB exchange rate does not incorporate 
    this assumption.
        Nevertheless, the Agency is proposing to retain the existing 5-dB 
    exchange rate because of feasibility considerations. Changing to a 3-dB 
    rate from a 5-dB rate would significantly reduce the amount of time 
    that miners could be exposed to higher sound levels without exceeding 
    the PEL. For example, MSHA estimates that the percentage of miners 
    whose exposure would be in violation of the PEL would just about double 
    if a 3-dB exchange rate is used. This means mine operators would have 
    to utilize controls to reduce exposures to the PEL much more 
    frequently. Moreover, more expensive controls would often be required; 
    if doses are doubling more quickly, the controls needed to reduce 
    overexposures to the PEL would have to be more effective. Furthermore, 
    if a 3-dB exchange rate is used, it is extremely difficult to reduce 
    the noise exposures to the PEL with currently available engineering or 
    administrative noise controls or a combination thereof. Accordingly, 
    moving the industry to a 3-dB exchange rate may not be feasible at this 
    time.
        The sound levels to be included in a miner's dose are being 
    expanded. At present, only exposures to sounds of 90 dBA and above are 
    included in determining a miner's dose under MSHA's standards. (Thus, 
    90 dBA is considered the ``threshold.'') The proposed rule would 
    include exposure to sound levels as low as 80 dBA. The Agency has 
    concluded that capturing such sound levels is necessary if it 
    establishes an action level based on an eight-hour time-weighted 
    average of 85 dBA. Among other reasons, exposure of a miner to an 
    extended shift (e.g.,16
    
    [[Page 66355]]
    
    hours) at just over 80 dBA can result in an exposure that exceeds the 
    action level. OSHA uses this threshold for its action level, but a 
    higher threshold for the PEL; based on the comments received in 
    response to its Advance Notice of Proposed Rulemaking, MSHA concluded 
    it would be easier for the mining industry to use a single threshold 
    for both purposes.
        While necessary, this change will generally result in higher dose 
    readings in both the coal and metal and nonmetal sectors than at 
    present. (See the discussion of exposure data in response to Question 
    5). In this case, however, MSHA has concluded that this change would 
    clearly be feasible for the industry.
        The proposed regulation would not allow dose measurements to be 
    adjusted to reflect the effect of hearing protectors. This provision 
    would reinforce MSHA's intent to preclude the current practice in the 
    coal mining industry of not issuing a citation based upon a noise 
    exposure that exceeds the PEL when the miners are wearing hearing 
    protection. (See Question 11 for additional information on this topic.)
    (10) What Controls Are Required Whenever a Miner's Exposure Exceeds the 
    Action Level?
        The proposal would require that all miners exposed above the action 
    level be provided special instruction in the hazards of noise and 
    protective methods. The training is to be provided annually for as long 
    as exposure exceeds the action level. (The nature of this instruction, 
    how it is to be provided, and how it can be coordinated with other 
    required miner training are discussed in response to other questions.)
    (11) What Additional Controls Are Required If a Miner's Exposure 
    Exceeds the Action Level but Is Below the PEL?
        An operator will be required to enroll a miner whose exposure 
    exceeds the action level in a hearing conservation program (HCP). While 
    enrollment in the HCP would require the operator to make annual 
    audiometric testing available to the miner, miners exposed to noise 
    below the PEL would have the right to decline taking any annual 
    audiometric testing. The requirements for such testing are discussed in 
    more detail in response to other questions.
        MSHA is seeking comments on how to minimize the burden on mine 
    operators of providing audiometric examinations for those miners with 
    only a temporary attachment to the mining work force (e.g., summer 
    employees), while recognizing the importance of detecting and tracking 
    hearing loss among those who switch jobs.
        In addition, the operator must provide properly fitted hearing 
    protection in 3 cases: before the initial hearing examination, if a 
    significant threshold shift in hearing acuity is detected, and at any 
    other time upon miner request.
        Both MSHA and OSHA normally require an employer or operator to 
    ensure that personal protective equipment is in fact used; an operator 
    can be cited for failure to enforce rules to this effect. In the case 
    of this proposal, however, MSHA is making two exceptions in that 
    regard. First, should the initial hearing examination take less than 6 
    months to provide, the operator will not be required to ensure the 
    provided hearing protection be worn. The operator is obligated to 
    ensure protector use if more time is needed for the baseline 
    examination (e.g., to wait for a mobile test van). Second, hearing 
    protection provided because of miner request does not generate an 
    operator obligation to enforce the use of the requested protection. At 
    exposure levels above the action level but below the PEL, the 
    proposal's goal is to encourage the use of hearing protection by 
    training, providing choice, and encouraging proper fit--but the 
    proposal would not require hearing protector use unless the miner has a 
    significant threshold shift or unless the miner has to wait more than 6 
    months for a baseline examination.
    (12) What Controls Are Required If a Miner's Exposure Exceeds the PEL?
        If a miner's noise dose exceeds the PEL, the proposal would require 
    the mine operator to use all feasible engineering and administrative 
    controls to reduce the miner's noise exposure to that level. The mine 
    operator has a choice of whether to use engineering controls, 
    administrative controls, or both; but if administrative controls are 
    utilized, a copy of the procedures involved must be posted, and copies 
    given to the affected miners.
        Under the proposal, a consistent hierarchy of controls is 
    established for all mines. Mine operators must first utilize all 
    feasible engineering and administrative controls to reduce sound levels 
    to the PEL before (as explained in response to question 15) relying on 
    other controls to protect against hearing loss. This approach is 
    consistent with that currently in place for metal and nonmetal mines, 
    but would be a change for coal mines. In the coal mining industry, MSHA 
    inspectors do not cite for noise overexposures without first deducting 
    from the measured dose the attenuating value of hearing protectors 
    being worn by the miners exposed to excessive levels of noise. In 
    practice, this means that personal protective equipment is in most 
    cases accepted as a substitute for engineering and administrative 
    controls.
        MSHA has conducted research on the attenuating value of hearing 
    protectors under actual mining conditions and has reviewed the 
    literature on this issue. MSHA is aware that NIOSH is considering new 
    approaches on how to establish a system that will accurately derate 
    hearing protector attenuation values for actual workplace conditions; 
    but the Agency's own research suggests that the attenuation of a 
    hearing protector is highly variable in practice, and that the amount 
    of attenuation cannot be predicted accurately. This is discussed in 
    part III of the Supplementary Information accompanying this notice.
        MSHA has also considered the data showing declining noise exposures 
    in the metal and nonmetal industry, and contrasted this with the data 
    on the coal mining industry.
        The Agency has concluded that, in practice, reliance upon hearing 
    protectors to reduce noise exposures simply does not provide effective 
    protection against hearing loss to miners. The Agency does not contend 
    that properly fitted and maintained hearing protectors are worthless; 
    on the contrary, the Agency is proposing to rely upon them as a 
    supplemental control, and has taken their value into account in 
    conducting its risk and benefit analyses. MSHA has concluded, however, 
    that hearing protectors should no longer be relied upon as a primary 
    means of control, and that this change can bring about dramatic 
    reductions in the rate at which coal miners would otherwise be expected 
    to incur hearing impairments.
    (13) For an Individual Mine Operator, What Are ``Feasible'' Engineering 
    and Administrative Controls?
        The proposal would require a mine operator to use only such 
    engineering controls as are technologically feasible, and to use only 
    such engineering and administrative controls as are economically 
    feasible for that mine operator. Those in the metal and nonmetal mining 
    industry are already familiar with the Agency's policies and practices 
    in this regard, but those in the coal mining industry may wish to take 
    note of the following few paragraphs.
        The Federal Mine Safety and Health Review Commission (Commission) 
    has addressed the issue of what MSHA must consider, with regard to 
    MSHA's existing noise standard for metal and
    
    [[Page 66356]]
    
    nonmetal mines, when determining what is a feasible noise control for 
    enforcement purposes at a particular mine. According to the Commission, 
    a control is considered feasible when: (1) The control reduces 
    exposure, (2) the control is economically achievable, and (3) the 
    control is technologically achievable. See Secretary of Labor v. 
    Callanan Industries, Inc., 5 FMSHRC 1900 (1983), and Secretary of Labor 
    v. A. H. Smith, 6 FMSHRC 199 (1984).
        In determining technological feasibility of a proposed control, the 
    Commission has ruled that a control is deemed achievable if through 
    reasonable application of existing products, devices, or work methods 
    with human skills and abilities, a workable engineering control can be 
    applied to the noise source. The control does not have to be ``off-the-
    shelf;'' but, it must have a realistic basis in present technical 
    capabilities.
        In determining economic feasibility, the Commission has ruled that 
    MSHA must assess whether the costs of the control are disproportionate 
    to the ``expected benefits'', and whether the costs are so great that 
    it is irrational to require its use to achieve those results. The 
    Commission has expressly stated that cost-benefit analysis is 
    unnecessary in order to determine whether a noise control is required. 
    According to the Commission, an engineering control may be feasible 
    even though it fails to reduce exposure to permissible levels contained 
    in the standard, as long as there is a significant reduction in 
    exposure. Todilto Exploration and Development Corporation v. Secretary 
    of Labor, 5 FMSHRC 1894 (1983). No guidance has been provided by the 
    Commission as to what level of reduction is considered significant. 
    However, the Commission has accepted the Agency's determination that a 
    3 dBA reduction is significant.
        In the metal and nonmetal mining industry, MSHA has interpreted the 
    ``expected benefits'' to be the amount of noise reduction achievable by 
    the control. MSHA generally considers a reduction of 3 dBA or more to 
    be a significant reduction of the sound level. Consequently, a control 
    that achieves relatively little noise reduction at a high cost could be 
    viewed as not meeting the Commission's test of economic feasibility.
        Accordingly, consistent with the case law, MSHA has considered 
    three factors in determining whether engineering controls are feasible 
    at a particular metal and nonmetal mine: first, the nature and extent 
    of the overexposure; second, the demonstrated effectiveness of 
    available technology; and third, whether the committed resources are 
    wholly out of proportion to the expected results. Before a violation of 
    these requirements of the standard could be found, MSHA would have to 
    determine that a worker has been overexposed; that administrative or 
    engineering controls are feasible; and that the mine operator failed to 
    install or maintain such controls.
        Part III of the Supplemental Information accompanying this notice 
    provides many examples of engineering controls that are feasible for 
    mine operators to utilize, and the Agency and the former Bureau of 
    Mines (USBOM) have available many other materials in this regard. 
    Nevertheless, the Agency welcomes information about particular 
    operations for which it may be particularly difficult to control noise.
    (14) Is It feasible for the Coal Mining Industry, and for the Metal and 
    Nonmetal Mining Industry, To Provide the Controls Proposed To Be 
    Required When Noise Exposures Exceed the PEL?
        Part IV of the Supplementary Information in this notice provides a 
    detailed discussion of the statute's requirements and the Agency's 
    analysis in this regard. The Agency has concluded that the coal mining 
    industry as a whole, and the metal and nonmetal mining industry as a 
    whole, can meet these requirements at a PEL set at a TWA8 of 90 
    dBA.
        In fact, the Agency seriously considered lowering the PEL. As noted 
    in response to Question 5, MSHA has concluded that there is a 
    significant risk of material impairment from noise exposures at or 
    above a TWA8 of 85 dBA. MSHA believes, however, that such a change 
    may not be feasible at this time for the mining industry. Based on an 
    analysis of exposure survey data, MSHA has concluded that if the PEL 
    were a TWA8 of 85 dBA, about two-thirds of the mine operators in 
    the metal and nonmetal mining industry, and about three-quarters of the 
    mine operators in the coal mining industry, would need to use 
    engineering and administrative controls to reduce current exposures. 
    Moreover, the engineering controls needed to reduce those exposures 
    would be more expensive, because they would have to be capable of 
    reducing the exposures further than with a PEL set at a TWA8 of 90 
    dBA.
    (15) What Supplemental Controls Are Required If a Miner's Exposure 
    Cannot Be Feasibly Reduced to the PEL?
        If reducing the dose to this level with such controls is not 
    feasible, the proposal requires the mine operator to use such controls 
    to lower the noise exposure as much as is feasible.
        In addition, in such cases, the proposal requires that the operator 
    take extra steps to protect miner hearing. The operator must ensure any 
    miner so exposed takes the annual hearing examinations, must provide 
    properly fitted hearing protection to all miners so exposed, and must 
    ensure the hearing protection is used by all miners so exposed.
        MSHA believes that when a miner is exposed to such high levels of 
    noise because engineering and administrative controls are not feasible 
    for an operator, these supplemental obligations are necessary to 
    protect miner hearing. Hearing protectors are not without their 
    discomforts, but the risk of hearing loss at such exposure levels ought 
    to be a controlling factor. While audiometric testing is not an 
    invasive procedure, the Agency is concerned that there may be economic 
    pressures and personal reasons that may lead miners to decline to take 
    hearing examinations. The information generated by these tests is 
    necessary, however, to trigger investigation of potentially serious 
    flaws in the layers of noise controls required at these high exposure 
    levels. In addition, the Agency believes that miners operating under 
    such high noise conditions should be aware of the severity of any 
    hearing loss; in a mining environment, this knowledge could have 
    implications for the safety of the miner and the safety of others. 
    Comments on this provision are specifically solicited.
    (16) Is There an Absolute Maximum Noise Dose?
        Under the proposal, a miner, as at present, is never to be exposed 
    to sound levels exceeding 115 dBA. This is because sound at that level 
    provides the full dose permitted in a matter of minutes.
        There is, however, no dose which the Agency would require to be 
    abated without regard to whether it is feasible for an individual mine 
    operator. The proposal does provide that should a miner's noise 
    exposure exceed a TWA8 of 105 dBA during any workshift, the mine 
    operator shall, in addition to taking all actions required to protect 
    miners exposed above the PEL, also require the miner to use dual 
    hearing protection, i.e., both a plug type and a muff type hearing 
    protector. A TWA8 of 105 dBA is a dose of 800% of the PEL, using a 
    5-dB exchange rate. In the notice accompanying this proposal, the 
    Agency presents information about the mining jobs at which the 
    exposures of this level are occurring, and requests comment on
    
    [[Page 66357]]
    
    whether there should be an absolute dose ceiling regardless of the 
    feasibility of control by an individual mine operator.
    (17) What Are an Operator's Obligations Under the Proposal To Monitor 
    Noise Exposures?
        The proposal would require mine operators to establish a system of 
    monitoring which effectively evaluates each miner's noise exposure. 
    This will ensure that mine operators have the means to determine 
    whether a miner's exposure exceeds any of the limitations established 
    by this section, as well as to assess the effectiveness of noise 
    controls. The proposed rule is performance oriented in that the 
    regularity and methodology used to make this evaluation are not 
    specified; MSHA's own measurements will enable it to check on the 
    effectiveness of an operator's monitoring program. Specific 
    requirements for biannual noise surveys, monitoring records, 
    supplemental noise surveys, calibration reports, survey reports, and 
    survey certifications now applicable to the coal sector would be 
    revoked, significantly reducing cost and paperwork burdens.
    (18) When Must Miners Be Notified of Monitoring Results?
        The proposal would require that miners be notified in writing 
    should their exposure exceed any of the levels specified by this 
    section--whether based on operator or MSHA evaluations of noise. Notice 
    would be required within 15 calendar days.
        The proposal has been designed to ensure that miners are made aware 
    of the hazards they currently face. Miners exposed above the action 
    level should be notified of that fact so, for example, they can 
    consider the importance of using provided, properly fitted and 
    maintained hearing protectors. On the other hand, the proposal does not 
    require notification of a particular miner if an exposure measurement 
    indicates that the miner's exposure has not changed and the miner has 
    within the last year been apprised of the same information. No 
    notification is required if a miner's measurement is below the action 
    level--although operators might wish to provide such notification if 
    this indicates a reduction in noise exposure.
    (19) What Rules Are There To Ensure That Required Hearing Protectors 
    Provide Effective Protection?
        Whenever hearing protectors are to be provided, they must be 
    provided in accordance with specific requirements. The miner is to have 
    a choice from at least one earplug type and muff type protector; and, 
    in the event dual hearing protection is required, a choice of one of 
    each. Whenever the mine operator is required to ensure that hearing 
    protection is worn (the circumstances are noted in response to prior 
    questions), it is worn by the miner when exposed to sound levels 
    required to be integrated into a miner's dose measurement, i.e., any 
    sound levels above 80 dBA. The hearing protector is to be fitted and 
    maintained in accordance with the manufacturer's instructions. Hearing 
    protectors and necessary replacements are to be provided at no cost to 
    the miner. Finally, should the miner suffer a medical pathology of the 
    ear, the miner is to be allowed to select a different hearing protector 
    from among those offered by the mine operator.
        MSHA has concluded that existing rating systems for hearing 
    protectors do not provide a reliable measure of effectiveness under 
    normal mining working conditions. The Agency believes that the best way 
    to ensure such devices can provide effective protection is to focus on 
    the conditions affecting hearing protector use.
    (20) How Frequently Must Required Training Be Provided?
        If a miner's noise exposure exceeds the action level, training is 
    to be provided annually. The training is to be provided when the miner 
    is first determined to have exceeded the action level and every 12 
    months thereafter that the miner continues to exceed that level.
        Annual refresher training is necessary to reinforce the proper 
    procedures for the use and care of hearing protectors, and the 
    importance of administrative and engineering controls. Additionally, it 
    serves to re-emphasize the hazards of noise and the purpose for 
    audiometric testing for those miners exposed above the PEL. MSHA 
    received comments in response to its Advance Notice of Proposed 
    Rulemaking (ANPRM) that supported an annual training requirement. 
    Studies have shown that the effectiveness of an HCP is highly dependent 
    on the proper use of hearing protectors and the commitment of both 
    management and the employees, both of which can be enhanced by 
    training.
    (21) What Specifications Are There With Respect to the Instruction To 
    Be Provided During Required Training?
        Miners would receive instruction in hearing protection: (1) the 
    need for such protection, (2) selection and fitting, and (3) proper use 
    of such protectors. Miners would also receive instruction about hearing 
    conservation programs: as to the operation of that program and the mine 
    operator's noise control efforts. There are no special qualifications 
    for instructors, nor any specifications on the hours of instruction. 
    Training is required to be provided without cost to the miner. The mine 
    operator would be required to certify the completion of any training 
    required by this part, and maintain the most recent certification for a 
    miner at the mine site for as long as the miner is required to use 
    hearing protectors or be enrolled in an HCP, and at least 6 months 
    thereafter.
    (22) Can the Required Training Be Covered During Part 48 Training?
        Yes, but it may not always be feasible to do so.
        MSHA considered whether the requirements of part 48, ``Training and 
    Retraining of Miners,'' were adequate to ensure the training required 
    under this part. The requirements of part 48 specify the initial and 
    annual retraining of all miners in a list of subjects, many specified 
    in the law itself (section 115 of the Mine Safety and Health Act). The 
    importance of this training is emphasized by statutory requirements for 
    the submittal of training plans, on the specification of the hours to 
    be devoted to the training, and on the qualifications of instructors. 
    Training is required on noise, but it is in general terms, covering the 
    purpose of taking exposure measurements and on any health control plan 
    in effect at the mine. Mine operators may provide additional training, 
    but the topics that need to be covered may make this impracticable 
    within the prescribed time limits.
        After considering the available information about the importance of 
    training requirements, and based upon its experience in implementing 
    the requirements of part 48, MSHA has determined that the requirements 
    of part 48 do not provide adequate noise training for those miners for 
    whom exposure is clearly a problem. Most current part 48 training is 
    neither comprehensive enough to provide such miners with the level of 
    education needed for the proper use of hearing protection devices, nor, 
    in the case of noisy mines, detailed enough on methods to reduce sound 
    levels.
        Nevertheless, MSHA believes compliance with this proposal can in 
    many cases be fulfilled at the same time as scheduled part 48 training. 
    The Agency does not believe special language in proposed part 62 is 
    required to permit this action under part 48, but welcomes comment in 
    this regard. Mine operators who can do so are free to fulfill their 
    noise training requirements by covering the topics in initial and
    
    [[Page 66358]]
    
    annual part 48 training, and may so certify on the separate form 
    required by this part. If incorporated into part 48, mine operators 
    would, however, be required to submit a revised training plan to the 
    appropriate district office for approval. Some mine operators, however, 
    may not be able to incorporate these topics in their part 48 plans. 
    Moreover, it is important to note that there are some circumstances in 
    which training required under the proposal will likely not fit within a 
    regular schedule, e.g., the training required when a miner's exposure 
    is determined to require selection of a hearing protector or a new 
    protector.
        MSHA has endeavored to make the training requirements as simple as 
    possible. If conducted separately from part 48 training, there are no 
    specifications on trainer qualifications, no minimal training time, nor 
    any training plans. If, however, the training is incorporated into part 
    48, then all applicable part 48 requirements will have to be met.
    (23) If a Mine Operator Is Required To Offer Audiometric Testing, When 
    Must a Baseline Audiogram Be Taken?
        It is critical to obtain a baseline audiogram before exposure to 
    hazardous noise. If this is not possible, then the baseline is to be 
    obtained as soon as is reasonably possible.
        Due to remote locations and intermittent operations of many mines, 
    MSHA determined that allowing six months (or 12 months if a mobile test 
    van is used) for offering the baseline audiogram was reasonable. The 12 
    month period would allow mine operators to schedule many baseline and 
    annual audiograms simultaneously, and thus, substantially reduce the 
    cost when mobile test vans are used. Miners enrolled in a hearing 
    conservation program would be provided hearing protection until such 
    time as the baseline audiogram is conducted. In the case of a miner who 
    has to wait more than 6 months for a baseline examination because of 
    the need for a mobile test van, and in the case of a miner whose 
    exposures cannot be reduced to the PEL through the use of all feasible 
    engineering and administrative controls, the operator would be required 
    to ensure the hearing protection is worn.
        MSHA has also determined that a 14-hour quiet period should precede 
    the baseline audiogram to ensure a valid result. Moreover, unlike the 
    OSHA rule, MSHA's proposal would not permit the use of hearing 
    protectors as a substitute for a quiet period. The Agency has 
    determined this is necessary to ensure that a temporary threshold shift 
    in hearing acuity does not occur during the quiet period, rendering the 
    baseline audiogram inaccurate. Moreover, MSHA's research has not shown 
    a reliable method for predicting hearing protector attenuation under 
    actual working conditions. Under the proposal, miners are to be 
    notified of the importance of compliance with the quiet period. MSHA is 
    not proposing to require this quiet period for annual audiograms, 
    although it may be in the mine operator's interest to do so.
    (24) What Qualification Requirements Are Proposed for Those Who Will 
    Take Audiograms?
        MSHA would require that an ``audiologist'' be certified by the 
    American Speech-Language-Hearing Association or licensed by a state 
    board of examiners. ``Qualified technicians'' would be required to have 
    been certified by the Council for Accreditation in Occupational Hearing 
    Conservation (CAOHC) or another recognized organization offering 
    equivalent certification. CAOHC or equivalent certification would 
    assure that the technicians are qualified. MSHA is not proposing to 
    require qualifications for physicians.
    (25) Does the Proposal Specify Audiometric Test Procedures?
         MSHA proposes not to include specific procedural requirements for 
    conducting audiometric tests, calibrating audiometers, and qualifying 
    audiometric test rooms. Instead, MSHA proposes a performance-oriented 
    requirement that audiometric testing be conducted in accordance with 
    scientifically validated procedures. MSHA would specify the test 
    frequencies, but would allow the physician or the audiologist to use 
    professional judgement in choosing the appropriate testing procedure(s) 
    and require certification of the scientific validity of the procedures.
        While this approach may require somewhat more in the way of 
    paperwork requirements, MSHA believes this is far preferable to the 
    alternative of a detailed specification standard, which could stifle 
    technology and impede improvements in methodology.
    (26) What Test Records Must Be Maintained?
        The proposal would also specify what records must be maintained at 
    the mine site and the retention duration. The proposed items included 
    in the audiometric test record--name, job classification, audiograms 
    and certifications as to the procedures used to take them, any exposure 
    determinations, and the results of any follow-up examinations--would 
    provide information essential for evaluating a miner's audiogram, among 
    other purposes.
        The proposal would require that the audiometric records be retained 
    for at least six months beyond the duration of the miner's employment. 
    The six-month retention period at the mine site would assure that test 
    records are not destroyed during what might be normal breaks in 
    employment and remain available for use by the mine operator to conduct 
    further evaluations upon the miner's return. In practice, MSHA believes 
    that many mine operators will keep a miner's audiograms long after the 
    miner's employment ceases, for use if the miner should file a 
    subsequent workers' compensation claim for hearing loss.
    (27) How Are Audiograms To Be Evaluated?
        MSHA's proposal would require that the mine operator inform the 
    person evaluating the audiogram of the requirements of this part and 
    provide such person with copies of the miner's audiometric test 
    records. The mine operator would be responsible for having a physician, 
    audiologist, or qualified technician determine if an audiogram is 
    valid, and to determine if a standard threshold shift in hearing acuity 
    (STS) or reportable hearing loss has occurred. Time frames within which 
    these actions must occur are part of the proposal.
        The proposal would permit, but not require, mine operators to 
    adjust audiometric test results by applying a correction for 
    presbycusis, the progressive loss of hearing acuity associated with the 
    aging process, before determining whether an STS or reportable hearing 
    loss has occurred, and it includes tables for this purpose. The 
    proposed adjustment for presbycusis is optional, however, if a mine 
    operator uses this approach, it must be applied uniformly to both the 
    baseline and annual audiograms in accordance with the procedures and 
    values listed in the proposed standard. Although this is the position 
    taken in the proposal, MSHA notes that NIOSH recently has advised 
    against the use of presbycusis correction factors. Moreover, the Agency 
    is concerned about locking-in particular presbycusis adjustment tables. 
    MSHA, therefore, requests additional comments on whether to use 
    presbycusis corrections for audiograms and, if so, how to
    
    [[Page 66359]]
    
    provide for such adjustment in a regulatory context.
    (28) What Happens If an Audiogram Is Not Valid?
        A prompt retest is required.
        When a valid audiogram cannot be obtained due to a suspected 
    medical pathology of the ear, and the physician or audiologist 
    evaluating the audiogram believes that the problem was caused or 
    aggravated by the miner's exposure to noise or the wearing of hearing 
    protectors, a miner must be referred for a clinical audiological or 
    otological evaluation as appropriate at mine operator expense.
        If the physician or audiologist concludes that the suspected 
    medical pathology of the ear which prevents obtaining a valid audiogram 
    is unrelated to the miner's exposure to noise or the wearing of hearing 
    protectors, the miner is to be advised of the need for an otological 
    evaluation; but in such cases, no financial obligation would be imposed 
    on the mine operator.
        A mine operator would be required to instruct the physician or 
    audiologist not to reveal to the mine operator any specific findings or 
    diagnoses unrelated to the miner's exposure to noise or the wearing of 
    hearing protectors without the written consent of the miner.
     (29) What Corrective Measures Are Required When a Standard Threshold 
    Shift in Hearing Acuity (STS) Is Detected?
        STS is defined in this proposal, as in OSHA's standard, as a change 
    in a worker's hearing acuity for the worse, relative to that worker's 
    baseline audiogram, of an average of 10 dB or more at 2000, 3000, and 
    4000 Hz in either ear.
        If the STS is determined to be permanent, a supplemental baseline 
    is established and this becomes the baseline for determining any future 
    STS. This definition is sufficiently restrictive to locate meaningful 
    shifts in hearing, yet not so stringent as to create unnecessary 
    follow-up procedures. The frequencies were chosen for this purpose to 
    ensure hearing losses are detected as soon as feasible. While NIOSH is 
    currently considering an approach that would not require averaging at 
    several frequencies, this remains under peer review; moreover, the 
    averaging of hearing levels at adjacent frequencies will reduce the 
    effect of testing errors at single frequencies.
        MSHA's proposal would require that, unless a physician or 
    audiologist determines that an STS is neither work-related nor 
    aggravated by occupational noise exposure, mine operators would have 30 
    days after the finding of an STS to--
        (1) Retrain the miner;
        (2) Provide the miner with the opportunity to select a hearing 
    protector, or a different hearing protector if the miner has previously 
    selected one; and
        (3) Review the effectiveness of any engineering and administrative 
    controls to identify and correct any deficiencies. The proposal also 
    requires that an operator ensure that a miner with an STS wear the 
    provided hearing protector.
        A hearing loss of 10 dB from a miner's prior hearing level is of 
    enough significance to warrant intervention by a mine operator, unless 
    it is determined the loss is not work-related. If the controls in place 
    are effective, including the training, this loss should not be 
    occurring. It should be noted that the retraining required is to take 
    place within 30 days after the finding of the STS, and thus it is 
    unlikely mine operators can satisfy this requirement through their part 
    48 training programs.
        MSHA's proposal does not include a provision for transferring a 
    miner who incurs repeated STS's. A miner transfer program would be 
    complex to administer, and would probably not be feasible in the metal 
    and nonmetal sector. This sector consists largely of smaller mines 
    which may be unable to feasibly rotate workers to other assignments on 
    a long-term basis.
     (30) When Must MSHA Be Notified About Hearing Loss?
        Pursuant to 30 CFR part 50, MSHA must be notified of any 
    ``reportable'' hearing loss. There is currently no uniform definition 
    of this term. The proposed rule would establish a uniform definition 
    for reporting a miner's hearing loss--a change in hearing acuity for 
    the worse relative to the miner's baseline audiogram of an average of 
    25 dB or more at 2000, 3000, and 4000 Hz in either ear. MSHA intends 
    that a loss for any miner need not be reported again until there is an 
    additional 25 dB loss. Having a uniform definition will ease reporting 
    burdens on mine operators while promoting the development of an 
    improved data base on hearing loss in the mining community.
        MSHA has two specific questions in this regard on which it is 
    seeking comment. First, MSHA would like comment on how to define 
    ``reportable'' hearing loss for those operators who do not have 
    audiometric test data. Not all mine operators will be required to 
    obtain audiometric test data under the proposed rule; thus, such 
    operators may not be able to use a definition of reportable hearing 
    loss defined in this manner.
        Second, MSHA is concerned that reporting only losses of 25 dB may 
    not provide MSHA a full picture of hearing loss in the mining industry. 
    A loss of 25 dB is used by many states as a basis for making disability 
    awards. Some have recommended that any STS (10 dB loss) should be 
    captured in a hearing loss data base. OSHA, which currently requires 
    any 25 dB loss to be captured in an employer's log, has proposed to 
    capture any 15 dB loss. MSHA accordingly solicits comment on this 
    point.
     (31) When Must a Miner Be Notified of Audiometric Testing Results?
        The proposal would require the mine operator, within 10 working 
    days of receiving the results of an audiogram, or receiving the results 
    of a follow-up evaluation, to notify the miner in writing of the 
    results and interpretations, including any finding that an STS or 
    reportable hearing loss has occurred. The notification would include an 
    explanation of the need and reasons for any further testing or 
    evaluation that may be required.
        MSHA believes that informing miners of the results of their 
    audiometric tests in a timely manner is critical to the success of an 
    HCP. Immediate feedback upon completion of the testing provides the 
    greatest benefit.
    (32) Who Has Access to Exposure and Test Records Maintained by Mine 
    Operators?
        Authorized representatives of the Secretaries of Labor and Health 
    and Human Services would have access to all records required under this 
    part.
        Moreover under the proposal, a miner or former miner, or his/her 
    designated representative with written consent, would have access to 
    all the records that the mine operator is required to maintain under 
    this part for that individual miner or former miner. Also, the miners' 
    representative is in all cases to have access, for miners they 
    represent, to noise training records and to notices required to be made 
    to miners exposed to noise above various levels.
        The mine operator would have 15 days from receipt of a written 
    request to provide such access. The proposal would define ``access'' as 
    the right to examine and copy records. The first copy of any record 
    requested by a person is to be provided without cost to that person, 
    and any additional copies requested by that person are to be provided 
    at reasonable cost.
    
    [[Page 66360]]
    
        Upon termination of employment, mine operators would be required to 
    provide a miner, without cost, an actual copy of all his or her own 
    records (those required under this part).
        The proposed standard would require mine operators to transfer all 
    records (or a copy thereof) required by this part to any successor mine 
    operator. The successor mine operator would be required to receive 
    these records and maintain them for the period required. Additionally, 
    the successor mine operator would be required to use the baseline 
    audiogram obtained from the original mine operator (or supplemental 
    baseline audiogram as appropriate) for determining an STS and 
    reportable hearing loss.
        MSHA has no uniform records access provision. The provisions 
    proposed here are similar to those in other health standards proposed 
    in recent years by the Agency. The Agency welcomes comment on whether 
    it needs to make changes to facilitate the use of electronic 
    recordkeeping systems.
    (33) How Does the Proposal Compare With the Existing Standards?
        MSHA has prepared two charts comparing some of the key features of 
    the proposed standard to MSHA's existing standards. A comparison to 
    OSHA's noise standard is also provided since many mine operators and 
    others are familiar with that standard.
        It is important the reviewers exercise some caution in using these 
    charts. The entries were ``shorthanded'' to fit into the chart. 
    Accordingly, other parts of this preamble should be consulted for 
    details. In comparing the proposed rule with OSHA's standard, for 
    example, reviewers interested in differences on the definition of a 
    hearing conservation program should consult the answer to Question 8; 
    those interested in differences on the threshold should consult the 
    answer to Question 9; those interested in differences on employer 
    obligations to ensure the wearing of provided hearing protections 
    should consult the answer to Question 11; and those interested in 
    differences about the use of hearing protection in lieu of a quiet 
    period before a baseline audiogram should consult the answer to 
    Question 23.
        Care should also be taken in consulting the existing standards 
    themselves. The entries in the charts and the discussions in the 
    preamble reflect legal and/or policy interpretations of the various 
    standards that now determine their meaning, something that would not be 
    apparent from an examination of the text of the standards.
        To conserve space, the following abbreviations are used in the 
    charts: HP (hearing protection), HCP (hearing conservation program), 
    STS (standard threshold shift), TWA8 (time-weighted eight-hour 
    average), dBA (decibel, A-weighted), PEL (permissible exposure limit); 
    ``admin'' (administrative), kHz (kilohertz), and N/A (none or not 
    applicable).
    
                                       Comparison Chart 1: Exposure/Dose Triggers                                   
    ----------------------------------------------------------------------------------------------------------------
                                                      Existing metal/                                               
       TWA8 noise above            Proposal               nonmetal            Existing coal             OSHA        
    ----------------------------------------------------------------------------------------------------------------
    85 dBA................  Provide training on    No action required...  No action required..  Enroll employee in  
                             noise; enroll miner                                                 HCP (must offer    
                             in HCP (must offer                                                  annual hearing     
                             annual hearing                                                      test); if more than
                             test); provide HP                                                   6 months before    
                             before baseline                                                     baseline audiogram 
                             audiogram taken, if                                                 taken (mobile van),
                             STS detected or upon                                                employee must be   
                             request of miner;                                                   provided and wear  
                             must ensure miner                                                   HP; employee must  
                             uses HP if more than                                                also be provided   
                             6 months for                                                        and use HP if STS  
                             baseline (mobile                                                    detected.          
                             van) or STS detected.                                                                  
    90 dBA................  Use all feasible       Use all feasible       Use all feasible      Use all feasible    
                             engineering and        engineering or         engineering or        engineering or     
                             admin. controls to     admin. controls to     admin. controls to    admin. controls to 
                             reach; if can't        reach; if can't        reach * * * but can   reach * * * but if 
                             reach 90 using such    reach 90 using such    first reduce          exposure less than 
                             controls, use          controls, then must    exposure reading by   100 dBA, can first 
                             controls to get as     also provide HP.       rated value of HP     reduce reading by  
                             low as possible,                              minus 7 unless        value of HP        
                             provide HP to all                             cited for failure     attenuation =.50 x 
                             miners, ensure HP                             to require HP use;    (rated value of HP 
                             used and ensure                               must enroll miners    minus 7).          
                             hearing tests taken.                          in HCP if cited.                         
    105 dBA...............  Dual HP must be        Limited requirement    n/a.................  n/a.                
                             provided and used.     for dual HP.                                                    
    ----------------------------------------------------------------------------------------------------------------
    
    
                                               Comparison Chart 2: Issues                                           
    ----------------------------------------------------------------------------------------------------------------
                                                            Existing metal/                                         
                  Issue                    Proposal            nonmetal          Existing coal           OSHA       
    ----------------------------------------------------------------------------------------------------------------
    Monitoring......................  Operator must       No requirement on   Mine operator       Employer must     
                                       establish system    mine operator.      required to         conduct          
                                       of monitoring                           conduct periodic    represent.       
                                       exposures.                              monitoring.         personal sampling
                                                                                                   if info suggests 
                                                                                                   noise exceeds    
                                                                                                   action level.    
    Notification of exposure level..  Notify miner of     Not required......  Not required......  Notify employee if
                                       measured exposure                                           exposure exceeds 
                                       level if: (a)                                               action level.    
                                       exposure changed,                                                            
                                       or (b) even if                                                               
                                       shows no change                                                              
                                       if miner not                                                                 
                                       notified within                                                              
                                       last year.                                                                   
    
    [[Page 66361]]
    
                                                                                                                    
    Threshold: lowest sound levels    80 dBA............  90 dBA............  90 dBA............  80 dBA for        
     counted.                                                                                      monitoring & HCP 
                                                                                                   enrollment but 90
                                                                                                   dBA for PEL.     
    Exchange rate...................  5 dB..............  5 dB..............  5 dB..............  5 dB.             
    Ceiling.........................  115 dBA...........  115 dBA...........  115 dBA...........  115 dBA.          
    Training on hearing protector     Annual if above     Part 48 general     Part 48 general     Annual if exposure
     selection & use.                  action level.       discussion.         discussion.         exceeds TWA8 of  
                                                                                                   85 dBA.          
    Training on audiology & employer  Annual if above     No................  No................  Audiology only;   
     program.                          action level.                                               annual if        
                                                                                                   enrolled in HCP. 
    Quiet period before aud. exam...  14 hours for        n/a...............  n/a...............  14 hours for      
                                       baseline                                                    baseline         
                                       audiogram; can                                              audiogram; can   
                                       not use hearing                                             use hearing      
                                       protectors.                                                 protectors.      
    Standard threshold shift........  10 dB av. shift @   n/a...............  n/a...............  10 dB av. shift @ 
                                       2, 3, & 4 KHz.                                              2, 3, & 4 KHz.   
    Reportable hearing loss.........  Must report 25 dB   Reporting required  Reporting required  No reporting; must
                                       av. shift @ 2, 3,   but level not       but level not       record 25 dB av. 
                                       & 4 kHz, either     defined.            defined.            shift @ 2, 3, & 4
                                       ear.                                                        kHz, either ear; 
                                                                                                   1/96 proposal    
                                                                                                   would drop to 15 
                                                                                                   dB.              
    Employee access to records......  Yes...............  No................  No................  Yes.              
    ----------------------------------------------------------------------------------------------------------------
    
    (34) Is MSHA Going To Write the Final Rule in Plain English so Miners 
    and Mine Operators Can Understand Their Obligations?
        The text of the proposed rule can be found at the very end of this 
    notice. While the Agency endeavored to write clearly, it is interested 
    in suggestions to make the final rule as comprehensible as possible to 
    mine operators and miners.
        MSHA has developed two examples, based on the proposed rule, to 
    illustrate some alternative approaches it could take.
        The first example illustrates one way in which a rule's 
    organization can be reformulated so as to serve as a more useful 
    reference tool. This proposal's table of contents begins as follows:
    
    62.100  Purpose and scope; effective date.
    62.110  Definitions
    62.120  Limitations on noise exposure
    
        The alternative version presents the table of contents as a series 
    of practical questions that are likely to be asked by the mining 
    community. The sections have been subdivided so as to address questions 
    one at a time. In the mining industry, the Department of the Interior 
    has also experimented with this approach, e.g., proposed coalbed 
    methane regulations (60 FR 47920).
    
    62.100  What is the purpose of requiring mine operators to limit 
    miner noise exposure?
    62.101  What kinds of mining operations are covered by this 
    regulation?
    62.102  When does this regulation take effect?
    62.110  What is meant by various technical terms used in this 
    regulation?
    62.120  How is a miner's noise dose calculated?
    62.121  How is dose converted to 8-hour time-weighted averages?
    62.122  Can a miner's dose measurement be adjusted to reflect the 
    type of hearing protection being worn by the miner?
    62.123  What are a mine operator's obligations to evaluate miner 
    noise exposure?
    62.124  When must miners and/or their representatives be notified of 
    measured exposures?
    62.130  What must a mine operator do whenever a miner's noise dose 
    exceeds the action level?
    62.131  What else must a mine operator do if a miner's noise dose 
    exceeds the action level but remains below the PEL?
    62.132  What else must a mine operator do if a miner's noise dose 
    exceeds the PEL?
    62.133  What is the highest sound level to which a miner may be 
    lawfully exposed?
    
        The contents of several of these sections might be more clear if 
    presented in a tabular format. This would be particularly useful where 
    the mine operator may have choices or has to do more than one thing. An 
    example involves the controls required at the action level. The current 
    proposal, as it would appear in the Code of Federal Regulations, as 
    paragraph (b) of proposed Sec. 62.120, is:
    
        (b) Action level. When a miner's noise exposure exceeds a 
    TWA8 of 85 dBA during any workshift, or equivalently a dose of 
    50%, the operator shall take the actions specified in paragraphs (b) 
    (1) and (2) of this section and, at the request of the miner, also 
    take the actions specified in paragraph (b)(3) of this section.
        (1) An operator shall provide the miner training that includes 
    the instruction required by Sec. 62.130, at the time exposure 
    exceeds the action level and every 12 months thereafter that 
    exposure continues to exceed the action level.
        (2) An operator shall enroll the miner in a hearing conservation 
    program which shall meet the requirements of Secs. 62.140 through 
    62.190. Moreover, the operator shall, with respect to any miner 
    enrolled in such program, provide hearing protection in accordance 
    with the requirements of Sec. 62.125 until such time as a baseline 
    audiogram has been obtained. If it takes more than 6 months to 
    conduct the baseline audiogram, or if the miner is determined to 
    have incurred an STS, the operator shall ensure that the hearing 
    protection is provided to the miner and worn by the miner.
        (3) At the request of any miner, the operator shall provide 
    hearing protection to the miner in accordance with the requirements 
    of Sec. 62.125.
    
        The alternative format would appear, using the revised numbering 
    and naming conventions from example 1, somewhat like the following:
    
    62.131  What specifically must a mine operator do if a miner's noise 
    dose exceeds the action level?
    
        If a miner's noise exposure exceeds a dose of 50% (a TWA8 of 
    85 dBA):
    
    ------------------------------------------------------------------------
                    You must                         Which means you        
    ------------------------------------------------------------------------
    (a) Provide training...................  Provide a miner with the       
                                              training required by MSHA's   
                                              rules--                       
                                             (1) When his or her exposure   
                                              exceeds the action level; and 
                                             (2) Every 12 months thereafter 
                                              that his or her exposure      
                                              continues to exceed the action
                                              level.                        
    
    [[Page 66362]]
    
                                                                            
    (b) Enroll the miner in a hearing        (1) Offer the miner annual     
     conservation program.                    audiometric examinations that 
                                              comply with MSHA's rules for  
                                              hearing conservation programs;
                                              and                           
                                             (2) Provide a miner with       
                                              hearing protection until a    
                                              baseline audiogram has been   
                                              taken; and in the event that  
                                              will take more than 6 months  
                                              due to the needs to wait for a
                                              mobile test van, require the  
                                              miner to use the hearing      
                                              protector; and                
                                             (3) Provide a miner with       
                                              hearing protection, and       
                                              require its use, whenever an  
                                              STS is detected.              
    (c) At the request of a miner, provide   Provide hearing protection in  
     the miner with hearing protection.       accordance with MSHA's rules. 
    ------------------------------------------------------------------------
    MSHA's rules for training are discussed in Sec.  62.137. MSHA's rules   
      for hearing conservation programs are discussed in Secs.  62.140      
      through 62.190. MSHA's rules for hearing protection are discussed in  
      Sec.  62.135.                                                         
    
        MSHA has not yet consulted with the Office of the Federal Register 
    on the specifics of such approaches; moreover, the examples noted above 
    should not be considered as necessarily accurately representing the 
    content of MSHA's proposed rule. These caveats notwithstanding, the 
    Agency is interested in the potential of these approaches, and would 
    welcome comment on these specific examples.
    (35) Is MSHA Going To Provide Adequate Guidance Before Implementing the 
    Rule?
        The Agency plans to take several steps toward this end.
        First, the Agency is proposing that the new standard not take 
    effect until one year after the date of publication of the final rule. 
    This should provide time to train MSHA personnel and provide mine 
    operators with technical assistance and guidance. An alternative would 
    be to phase in the new requirements. The Agency believes some could be 
    phased in quickly, but wants to avoid confusion. The Agency requests 
    comment on whether a phased-in approach is appropriate and how it might 
    most effectively be designed.
        In addition, the Agency is committed to issuing a compliance guide 
    for mine operators before a final rule takes effect. MSHA would welcome 
    suggestions on matters that should be discussed in such a guide.
        MSHA would also welcome comments on other actions it could take to 
    facilitate implementation, and in particular whether a series of 
    workshops would be useful.
    (36) Are There Special Enforcement Issues of Which the Mining Community 
    Should Take Note?
        Question 13 addresses the question of what constitutes ``feasible'' 
    engineering and administrative controls.
        Operators in the mining industry are aware that the Agency has 
    traditionally not cited an operator for exceeding the PEL unless the 
    Agency's measurement of noise shows that it exceeds a TWA8 of 92 
    dBA. This provides adequate room to accommodate, in an enforcement 
    context, any technical questions about MSHA's measurements. MSHA's 
    citation policy does not, however, alter operator obligations of the 
    rule, including those based on operator exposure readings.
        The Agency is interested in comment on whether the new final rule 
    should include a provision requiring operators to develop a written 
    plan in certain cases. At the present time, coal operators in violation 
    of the PEL must submit for approval a plan for the administration of a 
    continuing, effective program to assure compliance including provision 
    for reducing environmental noise levels, hearing protectors, and 
    audiograms. No such plans are provided in the metal and nonmetal 
    sector. The proposed rule, which would establish a uniform approach to 
    noise for both sectors, would eliminate the current coal requirement, 
    because MSHA does not believe such plans need to be created every time 
    an operator violates the PEL. The Agency recognizes, however, that 
    achieving effective compliance in some cases would be furthered by the 
    existence of a written plan. In particular, such plans may be 
    appropriate when there is a history of multiple noise violations, or a 
    failure to effectively abate. Such plans would include specific details 
    on how operators will comply with the final rule; a failure to comply 
    with the plan's specifications would be enforceable through MSHA's 
    normal citation/order process. Making explicit provision in the 
    standard for such plans would ensure clarity about the Agency's 
    enforcement policy on noise.
        The Agency notes that in some cases the proposal would require 
    operators to ensure certain miners wear hearing protection that is 
    provided, and ensure certain miners take tests that are offered. 
    Comment is welcome on how Agency personnel could distinguish these 
    miners from others.
    
    (B) Executive Order 12866
    
        In accordance with Executive Order 12866, MSHA has prepared a 
    preliminary analysis of the estimated costs and benefits associated 
    with the proposed revisions of the noise standards for coal and metal 
    and nonmetal mines.
        The preliminary RIA containing this analysis is available from 
    MSHA. MSHA welcomes comments on its analysis and methodology. The 
    proposal would cost approximately $8.3 million and would save 765 
    hearing impairment cases annually. The benefits are expressed in terms 
    of cases of hearing impairment that can be avoided and have not been 
    monetized. Although the Agency has attempted to quantify the benefits, 
    it believes that monetization of these benefits would be difficult and 
    inappropriate.
        Based upon the economic analysis, MSHA has determined that this 
    rule is not an economically significant regulatory action pursuant to 
    section 3(f)(1) of Executive Order 12866. The Agency does consider this 
    rulemaking significant under section 3(f)(4) of the Executive Order for 
    other reasons, and has so designated the rule in its annual agenda. 
    This means that while the Office of Management and Budget was provided 
    an opportunity to review this proposal and the preliminary RIA (as 
    discussed in the History section of this preamble), specific 
    determinations of the costs and benefits are not required pursuant to 
    section 6(a)(3)(C) of the Executive Order.
    
    (C) Paperwork Reduction Act
    
        This proposed rule contains information collections which are 
    subject to review by the Office of Management and Budget (OMB) under 
    the Paperwork Reduction Act of 1995 (PRA95). The title, description, 
    and respondent description of the information collection are shown 
    below with an estimate of the annual reporting burden. Included in the 
    estimate is the time for reviewing instructions, gathering and 
    maintaining the data needed, and completing and reviewing the 
    collection of information. With respect to the following collection of 
    information, MSHA invites comments on: (1) Whether the proposed 
    collection of information is necessary for proper performance of MSHA's 
    functions, including whether the information will have practical 
    utility; (2) the accuracy of MSHA's estimate of the burden of the 
    proposed collection of information, including the validity of the 
    methodology and assumptions used; (3) ways to enhance the quality, 
    utility, and
    
    [[Page 66363]]
    
    clarity of information to be collected; and (4) ways to minimize the 
    burden of the collection of information on respondents, including 
    through the use of automated collection techniques, when appropriate, 
    and other forms of information technology.
        These estimates are an approximation of the average time expected 
    to be necessary for a collection of information. They are based on such 
    information as is available to MSHA.
    Submission
        The Agency has submitted a copy of this proposed rule to OMB for 
    its review and approval of these information collections. Interested 
    persons are requested to send comments regarding this information 
    collection, including suggestions for reducing this burden, to the 
    Office of Information and Regulatory Affairs, OMB New Executive Office 
    Bldg., 725 17th St. NW., Rm. 10235, Washington, DC 20503, Attn: Desk 
    Officer for MSHA. Submit written comments on the information collection 
    not later than February 18, 1997.
    Description of Respondents
        Those required to provide the information are mine operators and 
    individuals who are paid to perform tasks for the mine operator (e.g., 
    physicians reporting the results of audiograms to the mine operator).
    Description
        The proposal contains information collection requirements in 
    Secs. 62.120, 62.130, 62.140, 62.150, 62.160, 62.170, 62.180, 62.190, 
    62.200, and 62.210. The following chart presents the paperwork 
    requirements by section.
    
           Net Information Collection Burden Hours by Proposed Section      
    ------------------------------------------------------------------------
                                    Paperwork requirement and               
              Section                   associated tasks            Hours   
    ------------------------------------------------------------------------
    62.120.....................  Evaluate miners' noise            (135,250)
                                  exposure; notify miner of                 
                                  overexposure; prepare and                 
                                  post administrative controls;             
                                  give miners copy of                       
                                  administrative controls.                  
    62.130.....................  Prepare and file a training          10,270
                                  certification.                            
    62.140.....................  Perform audiograms; notify           69,930
                                  miners to appear for testing              
                                  and need to avoid high noise.             
    62.150.....................  Compile an audiometric test           9,175
                                  record; obtain a                          
                                  certification.                            
    62.160.....................  Provide information and              21,350
                                  audiometric test record;                  
                                  perform audiometric retests.              
    62.170.....................  Perform otological evaluations        1,045
                                  and provide information and               
                                  notice.                                   
    62.180.....................  Prepare a training                      700
                                  certification for retrained               
                                  miners; review effectiveness              
                                  of engineering and                        
                                  administrative controls.                  
    62.190.....................  Inform miner of test results;         6,300
                                  inform miner of STS.                      
    62.200.....................  Provide access to records.....        1,255
    62.210.....................  Transfer records..............          235
                                                                ------------
          Total................  ..............................     (14,985)
    ------------------------------------------------------------------------
    
    
        These paperwork requirements have been submitted to the Office of 
    Management and Budget (OMB) for review under section 3504(h) of the 
    Paperwork Reduction Act of 1995 (PRA 95). Respondents are not required 
    to respond to any collection of information unless it displays a 
    currently valid OMB control number.
        The following chart summaries MSHA's estimates by section in 
    tabular form. Data is distributed by commodity. All numbers have been 
    rounded.
    
    
              Net Information Collection Burden Hours by Commodity          
    ------------------------------------------------------------------------
                                                                    Metal/  
                         Task                           Coal       nonmetal 
    ------------------------------------------------------------------------
    62.120  Limitations on Noise Exposure.........    (140,545)        5,295
    62.130  Training..............................        4,000        6,270
    62.140  Audiometric Testing Program...........       30,655       39,275
    62.150  Audiometric Test Procedures...........        3,930        5,245
    62.160  Evaluation of Audiograms..............        9,340       12,015
    62.170  Followup Evaluation...................          475          570
    62.180  Followup Corrective Measures..........          335          365
    62.190  Notification of Results...............        2,715        3,585
    62.200  Access to Records.....................          255        1,000
    62.210  Transfer of Records...................          100          135
                                                   -------------------------
          Total (discrepancies due to rounding)...     (88,740)       73,755
    ------------------------------------------------------------------------
    
        Alternatively, the paperwork hours may be distributed between small 
    and large mines. The following table provides this analysis. Small 
    mines are those with less than 20 employees.
    
              Net Information Collection Burden Hours by Mine Size          
    ------------------------------------------------------------------------
                         Task                          Small        Large   
    ------------------------------------------------------------------------
    62.120  Limitations on Noise Exposure.........     (15,510)    (119,740)
    62.130  Training..............................        2,965        7,305
    62.140  Audiometric Testing Program...........       19,270       50,660
    62.150  Audiometric Test Procedures...........        2,885        6,290
    62.160  Evaluation of Audiograms..............        6,185       15,170
    62.170  Followup Evaluation...................          250          800
    62.180  Followup Corrective Measures..........          160          540
    
    [[Page 66364]]
    
                                                                            
    62.190  Notification of Results...............        1,935        4,365
    62.200  Access to Records.....................          500          755
    62.210  Transfer of Records...................          185           50
                                                   -------------------------
          Total (discrepancies due to rounding)...       18,825     (33,805)
    ------------------------------------------------------------------------
    
        Metal/nonmetal mines would incur 75,080 burden hours under the 
    proposal and coal mines would incur 55,675 hours. For metal/nonmetal 
    mines, the existing burden is 1,325 hours as defined and calculated 
    under PRA 95; this makes the net burden for metal/nonmetal mines 73,755 
    hours. For coal mines, the net burden is 88,740 fewer hours than the 
    existing burden as calculated under PRA 95. The proposal would result 
    in a net decrease of 14,985 burden hours associated with information 
    collection from that associated with the current requirements. It 
    should be noted that the existing burden hours are currently approved 
    in three separate paperwork packages and reflect burden hours 
    calculated under the provisions of the 1980 Paperwork Reduction Act 
    (PRA 80). MSHA is in the process of updating and combining these three 
    packages. The Agency's official paperwork submission accompanying this 
    proposal includes a chart comparing the existing burden hours under PRA 
    80, the existing burden hours under PRA 95, and the proposed burden 
    hours under PRA 95.
        Additional detail is presented in the charts that follow. These 
    charts provide annual and annualized paperwork burden hours as measured 
    by PRA 95. Burden hours for tasks which predominantly would occur in 
    the first year only, dose determination and notification, are presented 
    in annualized form. Proposed Secs. 62.140(b)(3), 62.250 (b) and (c), 
    62.160 (a)(1) and (a)(3), 62.170 (b) and (c), 62.180(a), 62.190 (a)(1) 
    and (a)(2), 62.200(b) and 62.210(a) are anticipated to require the 
    paperwork burden of the mine operator providing instructions to the 
    clerical worker. This burden is included in the total hours per 
    regulation column.
    
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Number of                      Maintenance                 
                   Regulation                    Number of       Hours per       Number of     responses per    Total hours    and operating    Annualized  
                                                respondents      response        responses      respondent    per regulation       costs       capital costs
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Small Metal and Nonmetal Mines                                                             
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                            
        62.120(f)(1)........................           6,218            2.00             n/a             n/a           3,530        $597,922      $1,315,604
        62.120(f)(2)........................           6,218            0.08          35,300               6             490           1,253               0
        62.120(c)(1)........................              18            1.75              18               1              25               0               0
        62.120(c)(1)........................              18            0.05             103               5               5              26               0
        62.130(b)...........................           6,218            0.05          35,300               6           2,385           8,825               0
        62.140(b)(1)........................           2,430            1.00          13,779               6          13,780         413,370               0
        62.140(b)(3)........................           2,430            0.08          13,779               6           1,345           3,445               0
        62.150(b)...........................           2,430            0.08          13,779               6           1,345           3,445               0
        62.150(c)...........................           2,430            0.05          13,779               6             930           3,445               0
        62.160(b)(1)........................             300            1.50           1,720               6           2,585          86,000               0
        62.160(a)(1)........................           2,430            0.08          13,779               6           1,345           3,445               0
        62.160(a)(3)........................           2,430            0.05          13,779               6             930           3,445               0
        62.170(a)...........................              15            2.00              90               6             180          22,500               0
        62.170(b)...........................              15            0.08              90               6               9              23               0
        62.170(c)...........................              15            0.08              90               6               9              23               0
        62.180(a)...........................             320            0.05           1,808               6              90             452               0
        62.180(c)...........................              15            2.00              15               1              20               0               0
        62.190(a)(1)........................           2,430            0.08          13,779               6           1,345           3,445               0
        62.190(a)(2)........................             320            0.08           1,812               6             180           1,461               0
        62.200(b)...........................              60            0.10           4,374              12             440           1,094               0
        62.210(a)...........................             361            0.25             361               1             125               0               0
        Monitoring (existing)...............           1,705            2.00             n/a             n/a             970         163,953         360,744
                                                                                                                                                            
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Large Metal and Nonmetal Mines                                                             
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                            
        62.120(f)(1)........................           1,023            5.00             n/a             n/a           1,455         $98,372        $216,446
        62.120(f)(2)........................           1,023            0.08          75,700              75             875           2,687               0
        62.120(c)(1)........................              40            2.25              40               1              90               0               0
        62.120(c)(1)........................              40            0.05           2,972              70             150             726               0
        62.130(b)...........................           1,023            0.05          75,700              75           3,885          18,925               0
        62.140(b)(1)........................             301            1.00          22,328              75          22,330         669,840               0
        62.140(b)(3)........................             301            0.08          22,328              75           1,820           5,582               0
        62.150(b)...........................             301            0.08          22,328              75           1,820           5,582               0
        62.150(c)...........................             301            0.05          22,328              75           1,150           5,582               0
        62.160(b)(1)........................              40            1.50           2,790              70           4,185         139,500               0
        62.160(a)(1)........................             301            0.08          22,328              70           1,820           5,582               0
        62.160(a)(3)........................             301            0.05          22,328              70           1,150           5,582               0
        62.170(a)...........................               2            2.00             174              85             344          43,500               0
        62.170(b)...........................               2            0.08             174              85              15              44               0
    
    [[Page 66365]]
    
                                                                                                                                                            
        62.170(c)...........................               2            0.08             174              85              15              44               0
        62.180(a)...........................              50            0.05           3,490              70             175             873               0
        62.180(c)...........................              35            2.25              35               1              80               0               0
        62.190(a)(1)........................             301            0.08          22,328              75           1,820           5,582               0
        62.190(a)(2)........................              40            0.08           2,965              70             240             742               0
        62.200(b)...........................              10            0.10           5,601             560             560           1,400               0
        62.210(a)...........................              10            1.00              10               1              10               0               0
        Monitoring (existing)...............             250            5.00             n/a             n/a             355          24,040          52,895
                                                                                                                                                            
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Small Coal Mines                                                                    
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                            
        62.120(f)(1)........................           1,255            2.00             n/a             n/a             715        $120,681        $265,533
        62.120(f)(2)........................           1,255            0.08           9,020               7             120             320               0
        62.120(c)(1)........................              20            1.75              20               1              30               0               0
        62.120(c)(1)........................              20            0.05             173               7              10              43               0
        62.130(b)...........................           1,255            0.05           9,020               7             580           2,255               0
        62.140(b)(1)........................             536            1.00           3,851               7           3,851         115,530               0
        62.140(b)(3)........................             536            0.08           3,851               7             360             963               0
        62.150(b)...........................             536            0.08           3,851               7             360             963               0
        62.150(c)...........................             536            0.05           3,851               7             250             963               0
        62.160(b)(1)........................              70            1.50             480               7             720          24,050               0
        62.160(a)(1)........................             536            0.08           3,851               7             360           1,926               0
        62.160(a)(3)........................             536            0.05           3,851               7             250               0               0
        62.170(a)...........................               4            2.00              24               6              48           6,000               0
        62.170(b)...........................               4            0.08              24               6               2               6               0
        62.170(c)...........................               4            0.08              24               6               2               6               0
        62.180(a)...........................              60            0.05             507               8              25             127               0
        62.180(c)...........................              20            1.25              20               1              25               0               0
        62.190(a)(1)........................             536            0.05           3,851               7             360             963               0
        62.190(a)(2)........................              73            0.05             505               7              50             126               0
        62.200(b)...........................              15            0.10             610              40              60             131               0
        62.210(a)...........................             160            0.25             160               1              60               0               0
        Monitoring (existing)...............           1,762            0.50          25,334              14          12,670         357,492         169,434
        Audiograms (existing)...............              35            1.00              74               2              70           2,220               0
        Supplemental Noise Survey...........             420            0.05             840               2           (120)               0               0
        Supplemental Noise Survey...........             420            0.25           5,980              14         (2,990)               0               0
        Written HCP.........................              90            6.00              90               1           (535)               0               0
        Calibration Reports.................           1,762            0.25           1,762               1           (440)               0               0
        Survey Reports......................           1,762            0.05           1,762               1            (90)               0               0
        Monitoring Records..................           1,762            0.10          25,334              14         (2,530)               0               0
        Survey Certificates.................           1,762            0.05           1,762               1            (90)               0               0
                                                                                                                                                            
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Large Coal Mines                                                                    
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                            
        62.120(f)(1)........................             890            5.00             n/a             n/a           1,265         $85,582        $188,306
        62.120(f)(2)........................             890            0.08          66,667              75             770           2,367               0
        62.120(c)(1)........................              45            2.25              45               1              75           1,309               0
        62.120(c)(1)........................              45            0.05           5,237              75             290               0               0
        62.130(b)...........................             890            0.05          66,667              75           3,420          16,667               0
        62.140(b)(1)........................             334            1.00          25,007              75          25,007         750,210               0
        62.140(b)(3)........................             334            0.08          25,007              75           2,035           6,252               0
        62.150(b)...........................             334            0.08          25,007              75           2,035           6,252               0
        62.150(c)...........................             334            0.05          25,007              75           1,285           6,252               0
        62.160(b)(1)........................              40            1.50           3,126              80           4,690         156,300               0
        62.160(a)(1)........................             334            0.08          25,007              80           2,035           6,252               0
        62.160(a)(3)........................             334            0.05          25,007              80           1,285           6,252               0
        62.170(a)...........................               3            2.00             196              65             392          49,000               0
        62.170(b)...........................               3            0.08             196              65              16              49               0
        62.170(c)...........................               3            0.08             196              65              16              49               0
        62.180(a)...........................             400            0.05           3,908              35             195             977               0
        62.180(c)...........................              40            2.25              40               1              90               0               0
        62.190(a)(1)........................             334            0.05          25,007              75           2,035           6,252               0
        62.190(a)(2)........................              40            0.05           3,322              80             270             831               0
        62.200(b)...........................              10            0.10           1,934             194             195             484               0
        62.210(c)...........................              40            1.00              40               1              40               0               0
        Monitoring existing.................           1,134            0.50         169,424             150          84,710         230,077         239,932
        Audiograms (existing)...............               6            1.00             542              90             540               0               0
    
    [[Page 66366]]
    
                                                                                                                                                            
        Supplemental Noise Survey...........             293            0.05          43,712             150        (21,860)               0               0
        Supplemental Noise Survey...........             293            0.25             293               1            (40)               0               0
        Written HCP.........................              67            6.00              67               1           (405)               0               0
        Calibration Reports.................           1,134            0.25           1,134               1           (280)               0               0
        Survey Reports......................           1,134            0.05           1,134               1            (60)               0               0
        Monitoring Records..................           1,134            0.10         169,424             150        (16,940)               0               0
        Survey Certificates.................           1,134            0.05           1,134               1            (60)               0               0
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    
    (D) Regulatory Flexibility Act
    
        In accordance with Sec. 605 of the Regulatory Flexibility Act 
    (RFA), the Mine Safety and Health Administration certifies that the 
    noise proposal does not have a significant economic impact on a 
    substantial number of small entities. MSHA considers small mines to be 
    mines with fewer than 20 employees. However, for the purposes of the 
    RFA and this certification, MSHA has also evaluated the impact of the 
    proposal on mines up to and including those with fewer than 500 
    employees. No small governmental jurisdictions or nonprofit 
    organizations are affected. Under the Small Business Regulatory 
    Enforcement Fairness Act (SBREFA) amendments to the RFA, MSHA must 
    include in the proposal a factual basis for this certification. The 
    Agency also must publish the regulatory flexibility certification 
    statement in the Federal Register, along with the factual basis, 
    followed by an opportunity for comment by the public. The Agency has 
    consulted with the Small Business Administration (SBA) Office of 
    Advocacy and believes that this analysis provides a reasonable basis 
    for the certification in this case.
        MSHA specifically solicits comment on the Agency's determination in 
    this regulatory flexibility certification statement, including cost 
    data and data sources. To facilitate the public participation in the 
    rulemaking process, MSHA will mail a copy of the proposed rule, 
    including the preamble and regulatory flexibility certification 
    statement, to every mine operator.
    Factual Basis for Certification
        The Agency has used a quantitative approach in concluding that the 
    proposed rule does not have a significant impact on a substantial 
    number of small entities. The Agency performed its analysis separately 
    for two groups of mines: the coal mining sector as a whole, and the 
    metal and nonmetal mining sector as a whole. Based on a review of 
    available sources of public data on the mining industry, the Agency 
    believes that a quantitative analysis of the impacts on various mining 
    subsectors (i.e., beyond the 4-digit SIC level) may not be feasible. 
    The Agency requests comments, however, on whether there are special 
    circumstances that warrant separate quantification of the impact of 
    this proposal on any mining subsector, and information on how it might 
    readily obtain the data necessary to conduct such a quantitative 
    analysis. The Agency is fully cognizant of the diversity of mining 
    operations in each sector, and has applied that knowledge as it 
    developed the proposal.
        Under the RFA, MSHA must use the SBA definition for a small mine of 
    500 employees or fewer or, after consultation with the SBA Office of 
    Advocacy, establish an alternative definition for the mining industry 
    by publishing that definition in the Federal Register for notice and 
    comment. The alternative definition could be the Agency's traditional 
    definition of ``fewer than 20 miners,'' or some other definition. As 
    reflected in the certification, MSHA analyzed the costs of this 
    proposal for small and large mines using both the traditional Agency 
    definition, and SBA's definition, as required by RFA, of a small mine. 
    The Agency compared the costs of the proposal for small mines in each 
    sector to the revenues and profits for each sector for every size 
    category analyzed. In each case, the results indicated that the costs 
    as a percent of revenue are less than 1%. Further, the costs do not 
    appear to have any appreciable impact on profits.
        The following table summarizes the results of this analysis for 
    mines which employ fewer than 500 miners, at various sizes.
    
                                                       Small Mines: Costs Compared to Revenues and Profits                                                  
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             Total                                          
                                                                    Estimated    Estimated     Average     estimated    Estimated    Cost as %    Cost as % 
                                                                      costs       revenue    profit as %    profits      cost per    of revenue   of profit 
                                                                     (thous.)    (millions)   of revenue   (millions)   small mine                          
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    Coal Mines:                                                                                                                                             
        Small <20................................................ ($45)="" $855="" 3.82="" $33="" ($26)="" -0.01="" -0.14="" large="">=20...............................................          332       19,094         3.82          729          293         0.00         0.05
         Small <50............................................... 586="" 3,542="" 3.82="" 135="" 237="" 0.02="" 0.43="" large="">=50...............................................        (300)       16,408         3.82          627        (709)         0.00        -0.05
        Small <100............................................... 832="" 6,061="" 3.82="" 232="" 309="" 0.01="" 0.36="" large="">=100..............................................        (545)       13,888         3.82          531      (2,684)         0.00        -0.10
        Small <250............................................... 677="" 12,624="" 3.82="" 482="" 240="" 0.01="" 0.14="" large="">=250..............................................        (391)        7,326         3.82          280      (5,140)        -0.01        -0.14
        Small <500............................................... 382="" 19,117="" 3.82="" 730="" 132="" 0.00="" 0.05="" large="">=500..............................................         (95)          831         3.82           32      (8,660)        -0.01        -0.30
    M/NM Mines:                                                                                                                                             
        Small <20................................................ 4,437="" 11,929="" 4.55="" 543="" 479="" 0.04="" 0.82="" large="">=20...............................................        3,600       26,071         4.55        1,186        2,324         0.01         0.30
        Small <50................................................ 5,731="" 18,814="" 4.55="" 856="" 557="" 0.03="" 0.67="" large="">=50...............................................        2,306       19,186         4.55          873        4,359         0.01         0.26
    
    [[Page 66367]]
    
                                                                                                                                                            
        Small <100............................................... 6,323="" 23,047="" 4.55="" 1,049="" 599="" 0.03="" 0.60="" large="">=100..............................................        1,714       14,953         4.55          680        6,418         0.01         0.25
        Small <250............................................... 7,037="" 29,558="" 4.55="" 1,345="" 655="" 0.02="" 0.52="" large="">=250..............................................        1,000        8,442         4.55          384       14,492         0.01         0.26
        Small <500............................................... 7,571="" 32,134="" 4.55="" 1,462="" 702="" 0.02="" 0.52="" large="">=500..............................................          466        5,866         4.55          267       17,249         0.01         0.17
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    
        In determining revenues for coal mines, MSHA multiplied coal 
    production data (in tons) for mines in specific size categories 
    (reported to MSHA quarterly) by the average price per ton (from the 
    Department of Energy, Energy Information Administration, Annual Energy 
    Review 1995). For metal and nonmetal mines, the Agency estimated 
    revenues for specific mine size categories as the proportionate share 
    of these mines' contribution to the Gross National Product (from the 
    Department of the Interior, former Bureau of Mines, Mineral Commodity 
    Summaries 1996). Average profit as a percent of revenue for both coal 
    mines and metal and nonmetal mines comes from Dun & Bradstreet 
    Information Services, Industry Norms & Key Business Ratios, 1993-94.
        Based on the information in the Agency's preliminary Regulatory 
    Impact Analysis (summarized in the ``costs'' table in the Question and 
    Answer section of this preamble), the costs of the proposal for all 
    metal and nonmetal mines with fewer than 20 employees would be $4.6 
    million; the average cost of the proposal for a small metal and 
    nonmetal mine with fewer than 20 employees is about $500. The average 
    cost of the proposal for a small metal and nonmetal mine with fewer 
    than 500 employees is about $700. For small coal mines with fewer than 
    20 employees, the proposal is estimated to result in a small net 
    savings of about $30. This savings results from the proposed 
    elimination of a substantial paperwork burden that now exists in the 
    coal mine sector for monitoring miners' noise exposures. For small coal 
    mines with fewer than 500 employees, the proposal is estimated to 
    result in a small net cost of about $130.
    Regulatory Alternatives Rejected
        The limited impacts on small mines, regardless of size definition, 
    reflect decisions by MSHA not to propose more costly regulatory 
    alternatives. In considering regulatory alternatives for small mines, 
    MSHA must observe the requirements of its authorizing statute. Section 
    101(a)(6)(A) of the Mine Act requires the Secretary to set standards 
    which most adequately assure, on the basis of the best available 
    evidence, that no miner will suffer material impairment of health over 
    his/her working lifetime. In addition, the Mine Act requires that the 
    Secretary, when promulgating mandatory standards pertaining to toxic 
    materials or harmful physical agents, consider other factors, such as 
    the latest scientific data in the field, the feasibility of the 
    standard and experience gained under the Act and other health and 
    safety laws. Thus, the Mine Act requires that the Secretary, in 
    promulgating a standard, attain the highest degree of health and safety 
    protection for the miner, based on the ``best available evidence,'' 
    with feasibility as a consideration.
        As a result of this statutory requirement, MSHA seriously 
    considered two alternatives that would have significantly increased 
    costs for small mine operators--lowering the PEL to a TWA8 of 85 
    dBA, and lowering the exchange rate to 3 dB. In both cases, the 
    scientific evidence in favor of these approaches was strong. But in 
    both cases, for the purpose of this proposal, MSHA has concluded that 
    it may not be feasible for the mining industry to accomplish these more 
    protective approaches. The impact of these approaches on small mine 
    operators was an important consideration in this regard. Part IV of 
    this preamble contains a full discussion of MSHA's preliminary 
    conclusions about these alternatives. The public is invited to propose 
    other alternatives for consideration.
    Paperwork Impact
        In accordance with the Regulatory Flexibility Act and the Paperwork 
    Reduction Act of 1995 (PRA 95), MSHA has analyzed the paperwork burden 
    for small mines. While the proposal results in a net paperwork burden 
    decrease for all mines, it results in an increase in paperwork hours. 
    For mines with fewer than 20 miners the proposal would result in an 
    increase of about 18,800 hours, and with fewer than 500 miners it would 
    result in a decrease of about 14,985 hours. The bulk of the new hours 
    (greater than 80%) is derived from the audiometric testing program and 
    procedures. While mines with fewer than 20 employees in the coal and 
    metal and nonmetal sectors will have extra burden hours associated with 
    new requirements, the net burden hours for small coal mines are 
    actually reduced, because the proposal would eliminate current 
    requirements for biannual noise surveys and other miscellaneous reports 
    and surveys in that sector. However, at this size level, there are more 
    metal and nonmetal mines than there are coal mines. Thus, at this size 
    level, the proposal would result in a net gain in paperwork burdens.
        As required by PRA 95, MSHA has included in its paperwork burden 
    estimates the time needed to perform tasks associated with information 
    collection. For example, the proposed rule requires a mine operator to 
    notify a miner if the miner's noise exposure exceeds the action level. 
    In order to determine if notification is necessary, the mine operator 
    must perform dose determination monitoring. Although completion of the 
    notification would take 0.05 hour on average, the time for dose 
    determination must be included in the burden estimate according to the 
    new paperwork law. The proposal's average paperwork burden per small 
    metal and nonmetal mine is 4.8 hours and per small coal mine is 6 hours 
    per year.
    Other Relevant Matters
        In accordance with the Small Business Regulatory Enforcement 
    Fairness Act (SBREFA), MSHA is taking actions to minimize the 
    compliance burden on small mines. As discussed in the ``Questions and 
    Answers'' section of this preamble, MSHA is committed to writing the 
    final rule in plain English, so that it can be easily understood by 
    small mine operators. The proposed effective date of the rule would be 
    a year after final promulgation, to provide adequate time for small 
    mines to achieve compliance. Also, as stated
    
    [[Page 66368]]
    
    previously, MSHA will mail a copy of the proposed rule to every mine 
    operator which primarily benefits small mine operators. The Agency has 
    committed itself to issuance of a compliance guide for all mines, and 
    has invited comment on whether compliance workshops or other such 
    approaches would be valuable.
        MSHA is considering whether to continue to use ``fewer than 20 
    miners'' as the definition of a small mine for purposes of the 
    Regulatory Flexibility Act (RFA). For this rulemaking's Regulatory 
    Flexibility Analysis, the Agency is using fewer than 20 employees, in 
    addition to the SBA's definition of fewer than 500, as required by the 
    RFA. MSHA presently is consulting with the SBA Office of the Chief 
    Counsel for Advocacy in order to determine an appropriate definition to 
    propose to the public for comment in the future. For purposes of this 
    proposed rule on noise, MSHA has continued its past practice of using 
    ``under 20 miners'' as the appropriate point of reference, in addition 
    to SBA's definition. Reviewers will note that the paperwork and cost 
    discussions continue to refer to the impacts on ``small'' mines with 
    fewer than 20 employees. The Agency has not established a definition of 
    ``small entity'' for purposes of the final rule. Based on this 
    analysis, MSHA concludes that whatever definition of ``small entity'' 
    is eventually selected, the proposed noise rule does not have a 
    significant economic impact on a substantial number of small entities.
    
    (E) Unfunded Mandates Act
    
        MSHA has determined that, for purposes of Sec. 202 of the Unfunded 
    Mandates Reform Act of 1995, this proposal does not include any Federal 
    mandate that may result in increased expenditures by State, local, or 
    tribal governments in the aggregate of more than $100 million, or 
    increased expenditures by the private sector of more than $100 million. 
    Moreover, the Agency has determined that for purposes of Sec. 203 of 
    that Act, this proposed rule does not significantly or uniquely affect 
    small governments.
    Background
        The Unfunded Mandates Reform Act was enacted in 1995. While much of 
    the Act is designed to assist the Congress in determining whether its 
    actions will impose costly new mandates on State, local, and tribal 
    governments, the Act also includes requirements to assist Federal 
    agencies to make this same determination with respect to regulatory 
    actions.
    Analysis
        Based on the analysis in the Agency's preliminary Regulatory Impact 
    Statement (summarized in the ``cost'' table in the Questions and 
    Answers section of this preamble), the cost of this proposed rule for 
    the entire mining industry is less than $10 million. Accordingly, there 
    is no need for further analysis under Sec. 202 of the Unfunded Mandates 
    Reform Act.
        MSHA has concluded that small governmental entities are not 
    significantly or uniquely impacted by the proposed regulation. The 
    proposed rule will impact approximately 14,000 coal and metal and 
    nonmetal mining operations; however, increased costs would be incurred 
    only by those operations where noise exposures exceed the allowable 
    limits. MSHA estimates that approximately 350 sand and gravel or 
    crushed stone operations are run by state, local, or tribal governments 
    and would be impacted by this rule. MSHA anticipates that these 
    entities would be able to reduce noise exposure below the PEL via 
    engineering and administrative controls and would not need to use a 
    Hearing Conservation Program, thereby minimizing their costs. MSHA 
    estimates that increased costs for these entities would be about $500 
    per year which would be partially offset by reduced worker compensation 
    costs. Other tangible benefits include reduction in the number of cases 
    of hearing impairment in these entities.
        When MSHA issues the proposed rule, the Agency will affirmatively 
    seek input of any state, local, and tribal government which may be 
    affected by the noise rulemaking. This would include state and local 
    governmental entities who operate sand and gravel mines in the 
    construction and repair of highways and roads. MSHA will mail a copy of 
    the proposed rule to approximately 350 such entities.
        Following is MSHA's state-by-state listing of sand and gravel mines 
    owned or operated by state or local governments.
        The Agency welcomes any corrections.
    
             State/County Owned/Operated Sand and Gravel Operations         
                                [As of 12/08/95]                            
    ------------------------------------------------------------------------
                                                    State    County    City 
                        State                       owned    owned    owned 
    ------------------------------------------------------------------------
    ARIZONA......................................        2        2  .......
    ARKANSAS.....................................  .......        5  .......
    CALIFORNIA...................................  .......        4  .......
    COLORADO.....................................        4       27  .......
    IDAHO........................................  .......       13  .......
    ILLINOIS.....................................  .......        2  .......
    INDIANA......................................  .......        5  .......
    IOWA.........................................  .......        2  .......
    KANSAS.......................................  .......        2  .......
    MAINE........................................        5  .......  .......
    MARYLAND.....................................  .......  .......        6
    MICHIGAN.....................................  .......        8  .......
    MISSISSIPPI..................................  .......        5  .......
    MISSOURI.....................................  .......        8  .......
    MONTANA......................................        8       34  .......
    NEBRASKA.....................................  .......        2  .......
    NEVADA.......................................  .......        1  .......
    NEW MEXICO...................................  .......        4  .......
    NEW YORK.....................................  .......       15       95
    OKLAHOMA.....................................  .......        2  .......
    OREGON.......................................  .......       11  .......
    PENNSYLVANIA.................................  .......  .......        1
    SOUTH CAROLINA...............................  .......        1  .......
    SOUTH DAKOTA.................................  .......       15  .......
    TENNESSEE....................................  .......        3  .......
    TEXAS........................................  .......        6  .......
    UTAH.........................................        1        5  .......
    VERMONT......................................  .......  .......       11
    WASHINGTON...................................  .......        9  .......
    WISCONSIN....................................  .......       20        1
    WYOMING......................................  .......        1  .......
                                                  --------------------------
          Total 346..............................       20      212      114
    ------------------------------------------------------------------------
    
    (F) Rulemaking History
    
        MSHA's noise standards in metal and nonmetal mines (30 CFR 56/
    57.5050) and in coal mines (Secs. 70.500 through 70.511, and 
    Secs. 71.800 through 71.805) were first published in the early 1970's. 
    These standards, derived from the Walsh-Healey Public Contracts Act 
    occupational noise standard, adopted a TWA8 PEL of 90 dBA and a 5-
    dB exchange rate.
        Because of the differences between the standards for coal mines and 
    those for metal and nonmetal mines, members of the mining community 
    with operations in coal and metal and nonmetal requested that MSHA 
    revise its standards to provide one set of noise standards covering all 
    mines. Other mine operators with facilities regulated by both MSHA and 
    OSHA suggested that MSHA promulgate noise standards which are generally 
    consistent with OSHA standards. The United Mine Workers also requested 
    that the Agency reconsider the existing standards to address several 
    asserted deficiencies.
        Based on these comments and the incidence of noise-induced hearing 
    loss (NIHL) among miners, the Agency published an Advanced Notice of 
    Proposed Rulemaking (ANPRM) on December 4, 1989 (54 FR 50209). In this
    
    [[Page 66369]]
    
    ANPRM, the Agency solicited information for revision of the noise 
    standards for coal and metal and nonmetal mines. The Agency received 
    numerous comments which are reflected in this proposal from mine 
    operators, trade associations, labor groups, equipment manufacturers, 
    and other interested parties.
        A draft of the proposed rule and accompanying analyses was sent to 
    the Office of Management and Budget and to the Chief Counsel for 
    Advocacy of the Small Business Administration, in accordance with law 
    and Executive Order. Consultations with these two agencies were 
    completed within 90 days. No substantive changes to the proposal were 
    recommended during these consultations, nor were any made by MSHA. The 
    Agency did receive valuable advice on the presentation of its initial 
    Regulatory Flexibility Analysis and on displaying the results of its 
    paperwork analysis, so as to better highlight the Agency's compliance 
    with PRA 95 and SBREFA.
        In the Spring of 1996, the National Institute for Occupational 
    Safety and Health (NIOSH) released for peer review a draft criteria 
    document for occupational noise exposure to update the one issued in 
    1972. As indicated previously (see response to Question 6 in 
    ``Questions and Answers''), MSHA has determined that it would not be 
    appropriate to delay publication of this proposed rule to await the 
    issuance of the final NIOSH criteria document.
        A summary of the draft criteria document, prepared by NIOSH, is 
    reprinted here verbatim for those in the mining community who have not 
    otherwise received copies. This summary should provide ample notice of 
    the position NIOSH may be taking in a new criteria document.
    
    April 16, 1996--(NIOSH) Summary of Recommendations, Criteria for a 
    Recommended Standard: Occupational Noise Exposure
    
    1. Hearing Impairment and Risk Assessment
    
        The protection goal incorporated in most definitions of hearing 
    impairment has been to preserve hearing at critical audiometric 
    frequencies for speech discrimination. Hearing impairment as defined 
    by NIOSH in 1972 was an average of the hearing threshold levels 
    (HTLs) at the audiometric frequencies of 1000, 2000 and 3000 Hertz 
    (Hz) that exceeded 25 decibels (dB). The 4000-Hz audiometric 
    frequency has been recognized as being not only sensitive to noise 
    but also extremely important for hearing and understanding speech in 
    unfavorable or noisy listening conditions. Because listening 
    conditions are not always ideal in everyday life, and on the basis 
    of the American Speech Language-Hearing Association Task Force's 
    proposal made in 1981, NIOSH has modified its definition of hearing 
    impairment to include the 4000-Hz audiometric frequency for use in 
    assessing the risk of occupational NIHL. Hence, with this 
    modification, NIOSH defines material hearing impairment as an 
    average of the HTLs at 1000, 2000, 3000 and 4000 Hz that exceeds 25 
    dB.
        Because of the prolific occupational use of hearing protectors 
    since the early 1980's, new data that can be used to determine dose-
    response relationships for NIHL in U.S. workers are not known to 
    exist. NIOSH recently conducted a risk assessment on occupational 
    noise-induced hearing loss (NIHL) using the original definition of 
    hearing impairment and the hearing data from the 1972 criteria 
    document. Although the risk model used in the new assessment is 
    different from the risk model used in 1972, the excess risk 
    estimates derived in the new assessment are comparable to those 
    published in 1972. The excess risk at age 60 from a 40-year 
    occupational exposure to an average daily noise level of 85 
    decibels, a weighted network (dBA) is approximately 14%, versus the 
    16% published in 1972. With the new NIOSH definition of hearing 
    impairment, and based on the new risk assessment, the excess risk at 
    the 85-dBA REL is 8%. Thus, the new risk assessment did not revise 
    the excess risk at the 85-dBA REL upward, and although there is 
    still evidence of excess risk at exposure levels below 85 dBA, NIOSH 
    is recommending that the current REL be retained.
    
    2. Exchange Rate
    
        Health effect outcomes are dependent on exposure level and 
    duration. This relationship is called the ``exchange rate,'' which 
    is the increment in decibels that requires the halving of exposure 
    time. The most commonly used exchange rates are 3 dB and 5 dB. A 3-
    dB exchange rate requires that noise exposure time be halved for 
    each 3-dB increase in noise level; likewise, a 5-dB exchange rate 
    requires that exposure time be halved for each 5-dB increase. NIOSH 
    now recommends the 3-dB exchange rate. The 1972 criteria document 
    recommended the 5-dB exchange rate, which is what OSHA and MSHA 
    currently enforce. There is more scientific, although not 
    unequivocal, support for the 3-dB exchange rate than for the 5-dB 
    exchange rate, which is not based on scientific data and is derived 
    from a series of over-simplifications of the original criteria. The 
    3-dB exchange rate is recommended by the International Organization 
    for Standardization (ISO), and it is now enforced by most European 
    countries and some provinces of Canada. In the U.S., there have been 
    recent ``converts'' to the 3-dB exchange rate: the U.S. Air Force in 
    1993; and the American Conference of Governmental Industrial 
    Hygienists and the U.S. Army in 1994.
    
    3. Ceiling Limit
    
        In the 1972 criteria document, NIOSH recommended a ceiling limit 
    of 115 dBA, which is retained in this draft criteria document. 
    Exposures to noise levels greater than 115 dBA would not be 
    permitted regardless of the duration of the exposure. This ceiling 
    limit is based on the assumption that above a critical intensity 
    level the ear's response to energy no longer has a relation to the 
    duration of the exposure, but is only related to the intensity of 
    the exposure. Recent research with animals indicates that the 
    critical level is between 115 and 120 dBA. Below this critical 
    level, the amount of hearing loss is related to the intensity and 
    duration of exposure; but above this critical level, the 
    relationship does not hold. For a noise standard to be protective, 
    there should be a noise ceiling level above which no unprotected 
    exposure is permitted. Given the recent data, 115 dBA is a 
    reasonable ceiling limit beyond which no unprotected exposure should 
    be permitted.
    
    4. Hearing Protectors
    
        One consideration for selecting a hearing protector would be its 
    noise reduction capabilities, which are expressed in terms of a 
    noise reduction rating (NRR). The NRR is a single-number, 
    laboratory-derived rating required by the Environmental Protection 
    Agency (EPA) to be shown on the label of each hearing protector sold 
    in the U.S. In the late 1970's and early 1980's, two NIOSH field 
    studies found that insert-type hearing protectors in the field 
    provided less than one-half the attenuation measured in the 
    laboratory, and since the 1970's, 22 additional studies of ``real-
    world'' attenuation with a variety of hearing protectors have shown 
    similar results.
        In calculating the noise exposure to the wearer of a hearing 
    protector, OSHA has implemented the practice of derating the NRR by 
    one-half for all types of hearing protectors. In the 1972 criteria 
    document, NIOSH recommended the use of the equivalent full NRR 
    value, but now it recommends derating the NRR by 25%, 50% and 70% 
    for earmuffs, formable earplugs and all other earplugs, 
    respectively. This derating scheme is not perfect and is intended 
    only as an interim recommendation. If the testing and labeling 
    requirements for hearing protectors are to be changed, EPA must 
    initiate the rulemaking procedures because it has the statutory 
    authority. Given that the funding for EPA's Office of Noise 
    Abatement and Control was eliminated in the early 1980's, this 
    change is unlikely to occur in the near future.
        The draft also recommends that hearing protectors be worn for 
    any noise exposure over 85 dBA, regardless of exposure duration. 
    This measure is simplistic but extremely protective because its 
    implementation does not require the calculation of time-weighted-
    average (TWA) exposures. This ``hard-hat'' approach, as opposed to 
    predicating the requirement on TWA exposures, is a departure from 
    what was recommended in 1972. It appears to be a prudent policy, 
    which the U.S. Army has been using for years, but there are no data 
    in the document to support this recommendation.
    
    5. Exposure Level Requiring a Hearing Loss Prevention Program
    
        In this draft document, the requirement for a hearing loss 
    prevention program (HLPP), which includes audiometry, worker 
    education, etc., is triggered by the exposure level of 82 dBA, 8-
    hour TWA (i.e., \1/2\ of the REL). This level is essentially an 
    ``action level''--a concept developed in the mid-
    
    [[Page 66370]]
    
     1970's to address interday exposure variability and later adopted 
    in the Standards Completion Program as \1/2\ of an exposure limit. 
    In the 1972 criteria document, which preceded the Standards 
    Completion Program, the requirement for a HLPP began at the REL of 
    85 dBA, 8-hour TWA.
    
    6. Types and Frequency of Audiometric Examinations
    
        In this draft document, the recommended types (i.e., baseline, 
    monitoring, confirmation and exit audiograms) and frequency of 
    audiometric examinations are different from those in the 1972 
    criteria document. The new recommendations are in line with current 
    practices in HLPPs.
    
    7. Significant Threshold Shift
    
        Significant threshold shift is a shift in hearing threshold 
    levels, outside the range of audiometric testing variability 
    (5 dB), that warrants follow-up action to prevent 
    further hearing loss. NIOSH recommends an improved significant 
    threshold shift criterion, which is an increase of 15 dB in hearing 
    threshold at 500, 1000, 2000, 3000, 4000, or 6000 Hz that is 
    repeated for the same ear and frequency in back-to-back tests. This 
    criterion is different from that in the 1972 criteria document, and 
    has been selected from among several criteria on the bases of their 
    relative sensitivity and specificity. The new criterion has the 
    advantages of a high identification rate (identifying those workers 
    whose hearing thresholds have shifted toward higher levels) and a 
    low false-positive rate.
    
    8. Age Correction on Audiogram
    
        NIOSH recommends that age correction not be applied to an 
    individual's audiogram for the calculation of a significant 
    threshold shift. Although many people experience some decrease in 
    hearing sensitivity with age, age correction cannot be accurately 
    applied to audiograms in determining an individual's significant 
    threshold shift because the data on age-related hearing losses 
    describe only the statistical distributions in populations. Thus, 
    the median hearing loss attributable to presbycusis for a given age 
    group will not be generalizable to the presbycusis experienced by an 
    individual in that age group. The argument for age correction has 
    been that the employer should not be penalized for hearing losses 
    due to ageing. In the 1972 criteria document, NIOSH recommended age 
    correction but did not provide a rationale for it.
    
    9. Evaluation of Program Effectiveness
    
        To assess the effectiveness of a HLPP, it is necessary to have 
    an evaluation method that can monitor trends in the population of 
    workers enrolled in the program and thus indicate program 
    effectiveness before many individual shifts occur. In general, NIOSH 
    suggests that the success of a smaller HLPP should be judged by the 
    audiometric results of individual workers. An overall program 
    evaluation becomes critical when the number of workers grows so 
    large that one cannot simply look at each worker's audiometric 
    results and get an adequate picture of the program's efficacy. At 
    the present time, there is not one generally accepted method for the 
    overall evaluation of HLPPs. NIOSH recommends a significant 
    threshold shift incidence rate of 5% or less as evidence of an 
    effective HLPP. This method is currently the simplest procedure 
    available, and has no more disadvantages than other potential 
    evaluation methods.
    
    10. American National Standards Institute (ANSI)
    
        In the 1972 criteria document, NIOSH recommended several ANSI 
    standards for quality assurance in audiometry and in noise 
    measurements. Since then, these standards have been updated several 
    times. In the draft document, NIOSH recommends that these standards 
    be superseded with the latest versions as they become available. The 
    major advantage for this ``blanket'' endorsement is that the revised 
    criteria document will stay current with changing technology.
    
    II. The Risks to Miners
    
        This part of the preamble sets out the evidence collected by MSHA 
    to date with respect to whether there is a continuing risk to miners of 
    exposure to harmful levels of noise, despite existing standards, and 
    evidence on the level of that risk. Based upon this information, MSHA 
    has concluded that workplace noise exposure does continue to pose a 
    significant risk of material impairment of health and functional 
    capacity to miners.
        The data presented in this part provide a profile of the mining 
    population at risk at different levels of workplace noise exposure. The 
    noise exposure limitations being proposed by the Agency, described in 
    part III, would not eliminate the risk of material impairment--although 
    they would cut the present risk by two-thirds. (The feasibility of 
    further reducing risk is discussed in part IV. The data in this part II 
    were utilized by the Agency to assist it in determining the cost to 
    industry of reducing risk to various levels, and thus in reaching the 
    Agency's conclusions about economic feasibility.)
        There are a number of technical terms used throughout this section. 
    Reviewers not familiar with noise terminology should refer to the 
    discussion in part III of this preamble concerning proposed 
    Sec. 62.110, Definitions.
        All the studies discussed and cited in this part are included in 
    the references listed in part V, along with similar studies reviewed by 
    the Agency. All constitute part of the Agency's rulemaking record.
        The Agency is interested in receiving additional data with respect 
    to the risks of noise exposure.
    
    Defining the Problem
    
        Noise is one of the most pervasive health hazards in mining. 
    Exposure to hazardous sound levels results in the development of 
    occupational noise-induced hearing loss (NIHL), a serious physical, 
    psychological, and social problem. NIHL can be distinguished from aging 
    and medical factors, diagnosed, and prevented.
        The National Institute for Occupational Safety and Health (NIOSH) 
    has identified the ten leading work-related diseases and injuries in 
    the publication, ``Proposed National Strategies for the Prevention of 
    Leading Work-Related Diseases and Injuries, Part 2.'' According to 
    NIOSH, NIHL is among these ``top ten'' diseases and injuries.
        For many years, the risk of acquiring an NIHL was accepted as an 
    inevitable consequence associated with mining occupations. Miners use 
    mechanized equipment and work under conditions that often expose them 
    to hazardous sound levels. But MSHA standards, OSHA standards, military 
    standards, and others around the world have been established in 
    recognition of the controllability of this risk. Quieter equipment, 
    isolation of workers from noise sources, and limiting worker exposure 
    times are among the many well accepted methods now used to reduce the 
    costly incidence of NIHL.
        NIHL can be temporary or permanent depending on the intensity and 
    duration of the noise exposure. Temporary hearing loss results from 
    short term exposures to noise, with normal hearing returning after a 
    period of rest. Generally, prolonged exposure to noise over a period of 
    several years causes permanent damage to the auditory nerve: the higher 
    the sound level the more rapid the loss. The loss may be so gradual, 
    however, that a person may not realize that he or she is becoming 
    impaired until a substantial amount of hearing acuity is lost.
        Damage to the inner ear hair cells and auditory nerve makes it 
    difficult to hear as well as understand speech. This damage is 
    irreversible. Although people with NIHL sometimes can benefit from the 
    use of a hearing aid, the aid can never ``correct'' a hearing loss the 
    way eyeglasses usually can correct impaired vision. That is because 
    hearing aids primarily amplify sound without making it clearer or less 
    distorted. Also, they amplify the unwanted noise as well as the wanted 
    speech signals.
        People with significant NIHL have difficulty with the perception of 
    speech. They are often frustrated by missing information that is vital 
    for social or vocational functioning, and can produce workplace safety 
    hazards. Also, people around them need to speak louder, and more 
    clearly to be understood. In addition, background noise has a much more 
    disruptive effect on hearing-
    
    [[Page 66371]]
    
     impaired individuals because they are less able to differentiate 
    between the wanted signal and the unwanted background noise.
        There is a wealth of information on the relationship between noise 
    exposure and its auditory (hearing loss) and non-auditory 
    (physiological and psychosocial) effects.
        Numerous studies are available which describe the effects of noise 
    on hearing as a function of sound level and duration. Dose-response 
    relationships have been well established for noise equal to or greater 
    than average sound levels of 85 dBA (see, e.g., Lempert and Henderson, 
    1973).
        Although the non-auditory effects of noise are more difficult to 
    identify, document, and quantify than is hearing loss, recent 
    laboratory and field studies have implicated noise as a causative 
    factor in cardiovascular problems (Tomei et al., 1992 and Lercher et 
    al., 1993) and other illnesses such as hypertension (Talbott, 1990, and 
    Jansen, 1991). Decreasing the noise exposure from greater than 85 dBA 
    to less than 85 dBA significantly improved both the psychological and 
    physiological stress reactions (Melamed and Bruhis, 1996). However, 
    these studies of health effects have not been conclusive.
        In Earlog 6, Berger (1981) discussed the adverse non-auditory 
    effects of noise exposure. He suggests that effective hearing 
    conservation programs may not only prevent NIHL, but also improve 
    general employee health and productivity.
        Schmidt, et al. (1980) studied injury rates among workers in a 
    North Carolina cotton manufacturer exposed to noise ranging from 92 to 
    96 dBA. During the ten year time period studied, a significant 
    reduction in injury rates was observed for those workers who were in an 
    HCP, compared to those who were not.
        Safety risks can specifically be created because workers harmed by 
    NIHL can no longer hear safety signals. Most people with an NIHL have 
    reduced hearing acuity at the higher frequencies and lose their ability 
    to distinguish consonants on which the intelligibility of speech 
    depends. For example, they would have difficulty in distinguishing 
    between ``fish'' and ``fist.''
        Although MSHA recognizes that non-auditory effects of noise can be 
    significant, they are difficult to quantify; by contrast, the auditory 
    risks have a well-established dose-response relationship, and thus 
    provide a solid foundation on which to base regulatory action. The 
    Agency believes that reducing sound levels and protecting miners from 
    hazardous noise exposures will also reduce the non-auditory effects of 
    noise.
    
    Definition of Material Impairment
    
        Section 101(a)(6) of the Mine Safety and Health Act provides that 
    in setting standards to protect workers from the risks of harmful 
    physical agents, the Secretary ``shall set standards which most 
    adequately assure on the basis of the best available evidence that no 
    miner will suffer material impairment of health or functional capacity 
    even if such miner has regular exposure to the hazards dealt with by 
    such standard for the period of his working life.''
        While the material impairment to which the law refers is material 
    impairment of ``health or functional capacity'', the term material 
    impairment in the literature on noise risk generally refers to a level 
    of harm which is considered handicapping or even disabling--a 25 dB 
    hearing level (deviation from audiometric zero)--so this had to be the 
    basis of MSHA's estimates of the risk of material impairment. The 
    scientific community has actually utilized over time at least three 
    different definitions of what constitutes ``material impairment'' in 
    the case of NIHL. All use a 25 dB hearing level, but each definition 
    has used a different set of frequencies. Of these, the Agency believes 
    the one developed in 1972 by NIOSH and subsequently used by OSHA is 
    most appropriate of the three for evaluating the risks faced by miners 
    of developing disabling NIHL. The OSHA/NIOSH definition of material 
    impairment of hearing is a 25 dB hearing level averaged over 1000, 
    2000, and 3000 Hertz (Hz) in either ear. As noted in the History 
    section of this preamble, the Agency is aware that NIOSH is currently 
    considering a new definition that also includes hearing loss at 4000 
    Hz; but until such an approach is peer reviewed and approved, MSHA 
    believes it is not an appropriate basis for evaluating risk.
    Background
        Ideally, a definition of material impairment based solely upon 
    audiometric tests that measure individual ability to understand speech 
    would best characterize the debilitating effects of an NIHL. 
    Unfortunately, these tests are complicated, not well standardized, and 
    therefore seldom used to determine hearing impairment. For these 
    reasons, most definitions of impairment are based solely on pure tone 
    audiometry.
        Pure tone audiometric tests utilize an audiometer to measure the 
    hearing level threshold of an individual by determining the lowest 
    level of discrete frequency tones that the individual can hear. The 
    test procedures for conducting pure tone audiometry are relatively 
    simple, widely used, and have been standardized. Although there is 
    little debate among the scientific community about the usefulness of 
    pure tone audiometry in assessing hearing loss, some disagreement 
    exists as to the hearing level where hearing impairment begins and the 
    range of audiometric frequencies to use in making the assessment.
        In issuing its Hearing Conservation Amendment (46 FR 4078), OSHA 
    defined hearing impairment as exceeding a 25 dB ``hearing level'' 
    averaged over 1000, 2000, and 3000 Hertz (Hz) in either ear. Hearing 
    level is the deviation in hearing acuity from audiometric zero, the 
    lowest sound pressure level audible to the average normal-hearing young 
    adult. Positive values indicate poorer hearing acuity than audiometric 
    zero, while negative values indicate better hearing. Because OSHA based 
    its definition on a 1972 recommendation by NIOSH (1972), MSHA refers to 
    this definition as the OSHA/NIOSH criteria for hearing impairment.
        NIOSH specifically developed its definition of hearing impairment 
    for understanding speech under everyday (noisy) conditions. NIOSH 
    concluded that ``the basis of hearing impairment should be not only the 
    ability to hear speech, but also to understand speech,'' and this is 
    best predicted by the hearing levels at 1000, 2000, and 3000 Hz.
        When OSHA initially published its Hearing Conservation Amendment, 
    most medical professionals used the 1959 criteria developed by the 
    American Academy of Ophthalmology and Otolaryngology (AAOO), a subgroup 
    of the American Medical Association (AMA). This criteria (AAOO 1959) 
    defined hearing impairment as exceeding a 25 dB hearing level, 
    referenced to audiometric zero, averaged over 500, 1000, and 2000 Hz in 
    either ear (1959).
        The American Academy of Otolaryngology Committee on Hearing and 
    Equilibrium and the American Council of Otolaryngology Committee on the 
    Medical Aspects of Noise (AAO-HNS) has since modified the 1959 criteria 
    by adding the hearing level at 3000 Hz to the hearing levels at 500, 
    1000, and 2000 Hz (1979).
        Unlike the OSHA/NIOSH criteria, the AAOO 1959 and AAO-HNS 1979 
    criteria are for all types of hearing loss, including noise-induced 
    hearing loss (NIHL), and were mainly designed for hearing speech under 
    relatively quiet conditions.
    
    [[Page 66372]]
    
        In its ANPRM, MSHA asked for comments on a definition of hearing 
    impairment. Many commenters either directly or indirectly endorsed the 
    OSHA/NIOSH definition of hearing impairment. One commenter suggested 
    defining a significant material impairment as an average permanent 
    threshold shift of 25 dB or more at 1000, 2000, 3000, and 4000 Hz in 
    either ear. Other commenters supported the AAO-HNS 1979 criteria as the 
    level where impairment begins. (Several commenters suggested that MSHA 
    separately address a definition of hearing loss for reporting purposes; 
    this has been done, as discussed in part III of this preamble in 
    connection with proposed Sec. 62.190(b).)
    Discussion
        MSHA has determined that with respect to mine safety and health, 
    any definition of material impairment of hearing should relate to a 
    permanent, measurable loss of hearing which, unchecked, will limit the 
    ability to understand speech, as it is spoken in everyday social 
    (noisy) conditions. This is because speech comprehension is essential 
    for mine safety.
        Measures of hearing impairment depend upon the frequencies used in 
    calculating the hearing impairment. At relatively low sound levels 
    (between 80 dBA and 90 dBA) the hearing loss is confined to the higher 
    audiometric frequencies. In order to show the effect of noise below 90 
    dBA on hearing, inclusion of test frequencies above 2000 Hz is 
    necessary. MSHA agrees with the many comments and studies cited to show 
    that high frequency hearing is critically important for the 
    understanding of speech and that every day speech is sometimes 
    distorted and often takes place in noisy conditions.
        Therefore, MSHA has determined that for purposes of mine safety and 
    health, 3000 Hz should be included in any definition of material 
    impairment. In addition, 500 Hz should be excluded from any definition, 
    since it is not as critical for understanding speech and least affected 
    by noise. Of the three generally utilized definitions of noise--the 
    AAOO 1959, the AAO-HNS 1979, and the OSHA/NIOSH criteria--only the 
    latter meets this test.
        All three of the aforementioned definitions of noise use a 25 dB 
    hearing level. As noted previously, this level of hearing loss relative 
    to audiometric zero is actually well beyond that at which there is harm 
    to health and also well beyond that at which workers suffer a loss of 
    functional capacity. Nevertheless, this is the measure used in almost 
    all of the studies of risk of noise exposure that have been done. This 
    constrains the definition of material impairment the Agency utilizes to 
    evaluate the available risk data.
        Accordingly, solely for the purposes of evaluating the significance 
    of the available risk studies for miners, MSHA is adopting the OSHA/
    NIOSH criteria, a 25 dB hearing level averaged over 1000, 2000, and 
    3000 Hertz (Hz) in either ear, as its definition of material 
    impairment.
        With respect to risk evaluations, the number of persons meeting the 
    definition of impairment in any noise-exposed population will be higher 
    under the OSHA/NIOSH criteria than under the other criteria (AAOO 1959 
    and AAO-HNS 1979). This is because noise does not affect hearing acuity 
    equally across all frequencies. Typically, NIHL occurs first at 4000 
    Hz, then progresses into the lower and higher frequencies. The AAOO 
    1959 criteria is weighted toward the lower frequencies and was 
    developed to determine an individual's ability to communicate under 
    quiet conditions. Recognizing that an individual's ability to hear 
    speech in a noisy environment depends upon that person's ability to 
    hear sounds in the higher frequency range, the AAO-HNS added 3000 Hz to 
    the frequencies used in the AAOO 1959 criteria. The impact of this 
    modification is that the number of persons meeting the impairment 
    criteria in any noise-exposed population will be higher under the AAO-
    HNS 1979 criteria than under the AAOO 1959 criteria. With the 
    elimination of the hearing level at 500 Hz from the frequency range 
    used, the OSHA/NIOSH definition is weighted even more toward the higher 
    frequencies than the AAO-HNS 1979 criteria, and thus even more are 
    determined to be impaired.
        Moreover, selection of a criterion places some limitations on 
    direct comparisons of data sources available for risk assessment. Data 
    compiled using one definition of impairment are not readily 
    translatable to the others. Since there is no reliable mathematical 
    relationship among the three criteria for hearing impairment, it is not 
    possible to accurately predict the impact on a population using the 
    other two criteria when only the impact of one criterion is known. The 
    ideal way to convert from one hearing impairment criterion to another 
    would be to use the hearing level data for individual frequencies (raw 
    data), if still available from the individual audiograms. It is also 
    possible to crudely estimate the impact of one criterion to another 
    provided that summary data on individual frequencies are available. 
    Unfortunately, most of the data necessary to complete such conversions 
    are no longer available.
        In the discussion of risk that follows in the next section of this 
    preamble, sources of data based on all three definitions of impairment 
    are presented, so this caveat about translation needs to be kept in 
    mind. As it turns out, however, data using all three definitions tend 
    to demonstrate the same result.
    Risk of Impairment
        The studies of risk reviewed in this section consistently indicate 
    that the risk of developing a material impairment (as defined in the 
    prior section for purposes of this discussion) becomes significant over 
    a working lifetime when workplace exposure exceeds average sound levels 
    of 85 dBA. The data indicate that while lowering exposure from an 
    average sound level of 90 dBA to one of 85 dBA does not eliminate the 
    risk, it does reduce the risk by approximately half.
    Measuring Risk
        It is not possible to determine the risk to individual miners of 
    particular levels of noise. Some miners will suffer harm long before 
    other miners from the same level of noise, and it is not possible to 
    measure susceptibility in advance. Risks can, however, be determined 
    for entire populations. According to Melnick (1982), professor emeritus 
    of audiology at Ohio State University:
    
        Experts agree that information is available for deriving the 
    relationship of noise exposure to hearing loss. This information 
    serves as the basis for development of damage risk criteria. * * * 
    The relationship of noise to hearing is in the scientific domain. 
    The decisions inherent in development of damage risk criteria are 
    social, political, and economic. Damage risk criteria are 
    statistical concepts. Use of these criteria should be limited to 
    considerations of populations. Damage risk criteria are not 
    appropriate for use with individuals no matter how tempting such an 
    application might be.
    
        The probability of acquiring a ``material impairment'' of hearing 
    in a given population can be determined by extrapolating from data 
    obtained from a test population exposed to the same sound levels. Three 
    methods are generally used to express this population risk:
        (1) the hearing level of the exposed population;
        (2) the percent of an exposed population meeting the selected 
    criteria; and
        (3) the percent of an exposed population meeting the selected 
    criteria minus the percent of a non-noise exposed population meeting 
    the same criteria, provided both populations are
    
    [[Page 66373]]
    
    similar except for the occupational noise exposure.
        The latter of these expressions is more commonly known as ``excess 
    risk''. The excess risk method separates that percentage of the 
    population expected to develop a hearing impairment from occupational 
    noise exposure from that percentage expected to develop an impairment 
    from non-occupational causes--for example, the normal aging process or 
    medical problems. Hearing impairment risk data will be presented here 
    using the excess risk method, because MSHA has concluded that this 
    method provides the most accurate picture of the risk of hearing loss 
    resulting from occupational noise exposure. OSHA also used this method 
    in quantifying the degree of risk in the preamble to its Hearing 
    Conservation Amendment.
        Although studies of hearing loss consistently indicate that 
    increased noise exposure (either level or duration) results in 
    increased hearing loss, the reported risk estimates of occupational 
    NIHL can vary considerably from one study to another. As noted in the 
    prior section, the definition of ``material impairment'' used plays a 
    role. But two additional factors can be involved: the screening of the 
    control group (non-noise exposed group), and the threshold used to 
    define that group.
        Some researchers do not screen their study and control populations, 
    while others use a variety of different screening criteria. 
    Theoretically, screening would not have a significant impact on the 
    magnitude of occupational NIHL experienced by given populations as long 
    as the same criteria are used to screen both the noise and the non-
    noise populations being compared. However, when considering whether the 
    subjects have exceeded an established definition of material 
    impairment, failure to take into account any non-occupational noise 
    exposure and/or presbycusis (loss of hearing acuity due to aging) can 
    have a profound effect on the estimates of hearing acuity of an exposed 
    population. For example, if both the exposed and control populations 
    are screened to eliminate persons with a history of military exposure, 
    use of ototoxic medicines, noisy hobbies, conductive hearing loss from 
    acoustic trauma or illness, etc., the excess risk would be 
    significantly different from that determined using unscreened 
    populations.
        The data presented here all use the same threshold. The threshold 
    refers to that average sound level below which no adverse effects from 
    noise exposure are expected to occur. Although researchers Kryter 
    (1970) and Ambasankaran et al. (1981) have reported hearing loss from 
    exposure to average sound levels below 80 dBA, most believe that the 
    risk of developing a material impairment of hearing from exposure to 
    such levels over a working lifetime is negligible. Accordingly, almost 
    all noise risk studies consider the population exposed only to average 
    levels of noise below 80 dBA as a ``non-noise exposed'' control group. 
    In turn, this becomes the baseline from which the excess risk of being 
    exposed to noise at higher levels is measured. When OSHA evaluated the 
    risk of hearing loss for its hearing conservation amendment, it took 
    the position that it was appropriate to consider the non-noise exposed 
    control group to those exposed to sound levels below 80 dBA. MSHA, for 
    the purpose of this proposal, agrees with OSHA's assessment.
        As a result of these variations, the data available present a range 
    of risk estimates. As discussed later in the ``Conclusions'' section of 
    this part, for purposes of estimating the risks to miners, the Agency 
    has determined it should properly utilize the range of risk in those 
    studies based upon the OSHA/NIOSH definition of material impairment. As 
    noted in that discussion, however, even using the full range of the 
    data presented here would lead to a similar conclusion.
    Review of Study Data
        Table 1 is taken from the preamble to OSHA's Hearing Conservation 
    Amendment (46 FR 4084). It displays the percentage of the industrial 
    population expected to develop a hearing impairment meeting the AAOO 
    1959 criteria if exposed to the specified sound levels over a working 
    lifetime (40 years). This is a compilation of data developed by the 
    U.S. Environmental Protection Agency (EPA) in 1973, the International 
    Standards Organization (ISO) in 1975, and NIOSH in 1972. EPA, ISO, and 
    NIOSH developed their risk assessments using the AAOO 1959 criteria 
    because this was the format used by the original researchers in 
    presenting their data. OSHA's risk table was developed primarily from 
    studies of noise exposed populations in many sectors of general 
    industry.
    
                          Table II-1.--OSHA Risk Table                      
    ------------------------------------------------------------------------
                                                      Excess risk (%)       
                                              ------------------------------
                Sound level  (dBA)               ISO                        
                                                (1975)  EPA   NIOSH   Range 
    ------------------------------------------------------------------------
    80.......................................        0    5       3   0-5   
    85.......................................       10   12      15  10-15  
    90.......................................       21   22      29  21-29  
    ------------------------------------------------------------------------
    
        As seen in Table II-1, the excess risk of material impairment after 
    a working lifetime at an average noise exposure of 80 dBA is low, at an 
    average noise exposure of 85 dBA ranges from 10-15%, and at an average 
    noise exposure of 90 dBA it ranges from 21-29%. Table II-2 presents 
    further information on the risk assessments developed by NIOSH in their 
    criteria document (1972), one portion of which was included in Table 
    II-1. In Table II-2, data are based on both the AAOO 1959 criteria and 
    the OSHA/NIOSH criteria.
    
                          Table II-2.--NIOSH Risk Table                     
    ------------------------------------------------------------------------
                                                         Excess risk (%)    
                  Sound level  (dBA)               -------------------------
                                                     OSHA/NIOSH   AAOO 1959 
    ------------------------------------------------------------------------
    80............................................            3            3
    85............................................           16           15
    90............................................           29           29
    ------------------------------------------------------------------------
    
        As shown in Table II-2, NIOSH's risk assessment (1972) found little 
    difference using OSHA/NIOSH criteria when compared to AAOO 1959 
    criteria. However, as previously noted, NIOSH recommends using the 
    OSHA/NIOSH criteria for making risk assessments.
        Several researchers have commented on how adjustments to the 
    criteria used would affect such excess risk figures. Suter (1988) 
    estimates that the excess risk would be somewhat higher if 500 Hz was 
    excluded and 3000 Hz was included in the definition of material 
    impairment. Sataloff (1984) also reported on the effect of adding 3000 
    Hz into the impairment criteria. He recalculated the effect of 
    including hearing loss at 3000 Hz to the AAOO 1959 definition of 
    hearing impairment and found that the prevalence of hearing impairment 
    increased considerably. After 20 years of exposure to intermittent 
    noise that peaked at 118 dBA, 3% of the workers experienced hearing 
    impairment according to the AAOO 1959 definition of hearing impairment. 
    If the AAO-HNS 1979 definition is used, the percentage increases to 9%. 
    Royster et al. (1978) confirmed that the exclusion of 500 Hz and the 
    inclusion of 3000 Hz increased the number of hearing impaired 
    individuals during a study of potential
    
    [[Page 66374]]
    
    workers' compensation costs for hearing impairment. Using an average 
    hearing loss of 25 dB as the criteria, Royster found that 3.5% of the 
    industrial workers developed a hearing impairment according to AAOO 
    1959, 6.2% according to AAO-HNS 1979, and 8.6% according to OSHA/NIOSH.
        Table II-3, II-4 and II-5 display another set of data on the 
    working lifetime risk of material impairment, based upon the three 
    different criteria commonly used for defining material impairment. 
    Table II-3 is based on the AAO 1959 criteria, Table II-4 is based on 
    the AAO-HNS 1979 criteria, and Table II-5 is based on the OSHA/NIOSH 
    criteria. MSHA constructed these tables based on data presented in 
    Volume 1 of the Ohio State Research Foundation report (Melnick et al., 
    1980) commissioned by OSHA. The hearing level data, used to construct 
    the tables, were taken from summary graphs in the report. The noise 
    exposed population is 65 years old with 40 years of noise exposure. The 
    control group was not screened as to the cause of any hearing loss; 
    therefore, the high level of non-occupational hearing loss may 
    underestimate the excess risk from occupational noise exposure. The 
    researchers added the noise-induced permanent threshold shift component 
    to the control data. Noise-induced permanent threshold shift (NIPTS) is 
    the actual shift in hearing level only due to noise exposure after 
    corrections.
        As expected, the three tables produce different results, reflecting 
    that, for any given population, the excess risk for material impairment 
    will be greater using the AAO-HNS 1979 criteria than using the AAOO 
    1959. Likewise, the excess risk for material impairment will be greater 
    using the OSHA/NIOSH criteria than using the AAO-HNS 1979. All three 
    tables produce a smaller excess risk than did the data presented in 
    Table II-1.
    
    Table II-3.--Risk of Impairment Using AAOO 1959 Definition of Impairment
                        Using Melnick, et al., 1980 Data                    
    ------------------------------------------------------------------------
                                                                 Excess risk
                                                      Percent      (%) with 
                       Exposure                         with        noise   
                                                     impairment    exposure 
    ------------------------------------------------------------------------
    Non-noise.....................................         26.8          0.0
    80 dBA........................................         26.8          0.0
    85 dBA........................................         27.8          1.0
    90 dBA........................................         31.4          4.6
    ------------------------------------------------------------------------
    
    
        Table II-4.--Risk of Impairment Using AAO-HNS 1979 Definition of    
                   Impairment Using Melnick, et al., 1980 Data              
    ------------------------------------------------------------------------
                                                                 Excess risk
                                                      Percent      (%) with 
                       Exposure                         with        noise   
                                                     impairment    exposure 
    ------------------------------------------------------------------------
    Non-noise.....................................         41.6          0.0
    80 dBA........................................         41.8          0.2
    85 dBA........................................         44.4          2.8
    90 dBA........................................         50.0          8.4
    ------------------------------------------------------------------------
    
    
         Table II-5.--Risk of Impairment Using OSHA/NIOSH Definition of     
                   Impairment Using Melnick, et al., 1980 Data              
    ------------------------------------------------------------------------
                                                                 Excess risk
                                                      Percent      (%) with 
                       Exposure                         with        noise   
                                                     impairment    exposure 
    ------------------------------------------------------------------------
    Non-noise.....................................         48.5          0.0
    80 dBA........................................         48.7          0.2
    85 dBA........................................         51.5          3.0
    90 dBA........................................         57.9          9.4
    ------------------------------------------------------------------------
    
        Tables II-6 and II-7 present data derived by Melnick in Forensic 
    Audiology (1982) for damage risk due to noise exposure. These tables 
    use the AAO-HNS 1979 criteria. In these tables, the population is 60 
    years old with 40 years of exposure to the specified sound levels. In 
    both tables, the data represent NIPTS (noise induced permanent 
    threshold shift) calculated by Johnson, but the screening used in the 
    two tables is different. Melnick's data in Table II-6 is based upon the 
    screened presbycusis data (i.e. screened for non-occupational hearing 
    loss) of Robinson and Passchier-Vermeer, whereas Table II-7 is based on 
    unscreened non-occupational hearing loss data from the 1960-62 U.S. 
    Public Health Survey.
        Overall, the excess risk information presented in these tables is 
    closer to that in Table II-1 than to that in Tables II-3, II-4, and II-
    5, but still different. Tables II-6 and II-7 directly illustrate the 
    effect of screening populations in determining excess risk due to 
    occupational noise exposure. As seen in these tables, the percent with 
    impairment is greater in the table constructed with an unscreened 
    population as the base.
    
      Table II-6.--Risk of Impairment Using Presbycusis Data of Passchier-  
                              Vermeer and Robinson                          
    ------------------------------------------------------------------------
                                                                 Excess risk
                                                      Percent      (%) with 
                       Exposure                         with        noise   
                                                     impairment    exposure 
    ------------------------------------------------------------------------
    75 dBA........................................            3            0
    80 dBA........................................            5            2
    85 dBA........................................            9            6
    90 dBA........................................           21           18
    ------------------------------------------------------------------------
    
    
    Table II-7.--Risk of Impairment Using Non-occupational Hearing Loss Data
                             of Public Health Survey                        
    ------------------------------------------------------------------------
                                                                 Excess risk
                                                      Percent      (%) with 
                       Exposure                         with        noise   
                                                     Impairment    exposure 
    ------------------------------------------------------------------------
    75 dBA........................................           27            0
    80 dBA........................................           29            2
    85 dBA........................................           33            6
    90 dBA........................................           40           13
    ------------------------------------------------------------------------
    
        Chart ER1 displays the results of the various models. It should be 
    noted that both the P/V/Robinson (data from Table II-6) and the PHS 
    model (data from Table II-7) used the AAO-HNS 1979 criteria.
        As noted in the History section of this preamble, the Agency is 
    aware that NIOSH is currently working on revising its estimates using a 
    different model and taking hearing loss at an additional frequency into 
    account; but until such an approach is peer reviewed and finalized, 
    MSHA has concluded it should not be considered here.
        As illustrated by Chart ER1, the exact numbers of those at risk 
    varies with the study--because of the definition of material impairment 
    used, and because of the selection and threshold of the control group. 
    Notwithstanding these differences, the data consistently demonstrate 
    three points: (1) the excess risk increases as noise exposure 
    increases; (2) there is a significant risk of material impairment of 
    hearing loss for workers exposed over their working lifetimes to 
    average sound levels of 85 dBA; and (3) lowering the exposure from 
    average sound levels of 90 dBA to average sound levels of 85 dBA 
    reduces the excess risk of developing a material impairment by 
    approximately half.
    
    BILLING CODE 4510-43-P
    
    [[Page 66375]]
    
    [GRAPHIC] [TIFF OMITTED] TP17DE96.002
    
    
    
    BILLING CODE 4510-43-C
    
    Related Studies of Worker Hearing Loss
    
        There is a large body of data on the effects of varying industrial 
    sound levels on worker hearing. Some of these studies specifically 
    address the mining industry; moreover, MSHA has determined that 
    regardless of the industry in which the data were collected, exposures 
    to similar sound levels will result in similar degrees of material 
    impairment in the workers. These studies are supportive of the 
    conclusions reached in the previous section about noise risks at 
    different sound levels.
        OSHA's 1981 preamble to its Hearing Conservation Amendment referred 
    to studies conducted by Baughn, Burns and Robinson, Martin, et al., and 
    Berger et al.
        Baughn (1973) studied the effects of average noise exposures of 78 
    dBA, 86 dBA, and 90 dBA on 6,835 industrial workers employed in 
    Midwestern plants producing automobile parts. Noise exposures for these 
    workers were measured for 14 years and, through interviews, exposure 
    histories were estimated as far back as 40 years. The control and the 
    noise-exposed groups were not screened for anatomical abnormalities of 
    the ear.
        Baughn used his data to provide estimates of the hearing levels of 
    workers exposed to 80 dBA, 85 dBA, and 92 dBA and extrapolated the 
    exposures up to 115 dBA. Based upon the analysis, the researcher 
    constructed an idealized graph which illustrated that 43% of 58-year 
    old workers exposed for 40 years to noise at 85 dBA would meet the AAOO 
    1959 criteria for hearing impairment. However, 33% of an identical non-
    noise exposed population would be expected to meet the same impairment 
    criteria. The excess risk from exposure to noise at 85 dBA, therefore, 
    would be 10%. Using the same procedure, the excess risk for 80 dBA is 
    0% and for 90 dBA it is 19%.
        Burns and Robinson (1970) studied the effects of noise on 759 
    British factory workers exposed to average sound levels between 75 dB 
    and 120 dB with durations ranging between one month and 50 years. The 
    control group consisted of 97 non-noise exposed workers. Thorough 
    screening removed the workers with exposure histories which were not 
    readily quantifiable, exposure to gunfire, ear disease or abnormality, 
    and language difficulty.
        For this study, Burns and Robinson analyzed 4,000 audiograms and 
    found that the hearing levels of workers exposed to low sound levels 
    for long periods of time were equivalent to other workers exposed to 
    higher sound levels for shorter durations. From the data, the 
    researchers developed a mathematical model that predicts hearing loss 
    between 500 Hz and 6000 Hz in certain segments of the exposed 
    population. Using Burns and Robinson's mathematical model, MSHA 
    constructed Chart ER2. The chart shows that a noise exposure of 85 dBA 
    over a 40-year career is clearly hazardous to the hearing acuity of 60-
    year-old workers.
    
    BILLING CODE 4510-43-P
    
    
    [[Page 66376]]
    
    [GRAPHIC] [TIFF OMITTED] TP17DE96.003
    
    
    
    BILLING CODE 4510-43-C
    
        Martin et al. (1975) studied the prevalence of hearing loss in a 
    group of 228 Canadian steel workers, ranging in age from 18 to 65 years 
    of age, by comparing them to a control group of 143 office workers. The 
    researchers reported that the risk of hearing impairment (average of 25 
    dB at 500, 1000, and 2000 Hz) increases significantly between 85 dBA 
    and 90 dBA. Up to 22% of the population would be at risk of incurring a 
    hearing impairment with a 90 dBA PEL compared to 4% with an 85 dBA PEL. 
    Both the noise exposed and the control groups were screened to exclude 
    those workers with non-occupational hearing loss.
        Berger, Royster, and Thomas (1978) studied 42 male and 58 female 
    workers employed at an industrial facility. The study included a 
    control group of 222 persons that was not exposed to occupational 
    noise. Of the 322 individuals included in the study, no one was 
    screened for exposures to non-occupational noise from past military 
    service, farming, hunting, or shop work, since these exposures were 
    common to all. The researchers found that exposure to a daily steady-
    state Leq of 89 dBA for 10 years caused a measurable hearing loss 
    at 4000 Hz. According to the researchers, the measurable loss was in 
    close agreement with the predictions of Burns and Robinson, Baughn, 
    NIOSH, and Passchier-Vermeer.
        Passchier-Vermeer (1974) reviewed the results of eight field 
    investigations on hearing loss among 20 groups of workers. About 4,600 
    people were included in the analysis. The researcher concluded that the 
    limit of permissible noise exposure (defined as the maximum level which 
    did not cause measurable noise-induced hearing loss, regardless of 
    years of exposure) was shown to be 80 dBA. Furthermore, the researcher 
    found that noise exposures above 90 dBA caused considerable hearing 
    loss in a large percentage of employees and therefore, recommended that 
    noise control measures be instituted at this level. The researcher also 
    recommended that audiometric testing be implemented when the noise 
    exposure exceeds 80 dBA.
        NIOSH (Lempert and Henderson, 1973) published a report in which the 
    dose-response relationship for noise-induced hearing loss was 
    described. NIOSH studied 792 industrial workers whose average daily 
    noise exposures were 85 dBA, 90 dBA, and 95 dBA. The noise-exposed 
    workers were compared to a group of controls whose noise exposures were 
    lower than 80 dBA. The subjects ranged in age from 17 to 65 years old. 
    The exposures were primarily to steady-state noise but the exposure 
    levels fluctuated slightly in each category. Both the noise-exposed and 
    control groups were screened to exclude those exposed to gunfire as 
    well as those who showed some sign of ear disease or audiometric 
    abnormality. The report clearly shows that workers whose noise 
    exposures were 85 dBA experienced more hearing loss than the controls. 
    As the noise exposures increased to 90 dBA and 95 dBA, the magnitude of 
    the hearing loss increased.
        NIOSH (1976) published the results from a study on the effects of 
    prolonged exposure to noise on the hearing acuity of 1,349 coal miners. 
    From this study, NIOSH concluded that coal miners were losing their 
    hearing acuity at a faster rate than would be expected from the 
    measured environmental sound levels. While the majority of noise 
    exposures were less than a TWA8 of 90 dBA, the measured hearing 
    loss of the older coal miners was indicative of noise exposures between 
    90 dBA and 95 dBA. Only 12% of the noise exposures exceeded a TWA8 
    of 90 dBA. NIOSH, however, offered as a possible explanation that some 
    miners are exposed to ``very intense noise'' for a sufficient number of 
    months to cause the hearing loss.
        Coal miners in the NIOSH (1976) study had a greater percent of 
    impairment than the non-occupational exposed group (control group) at 
    each age level. Using OSHA/NIOSH definition of impairment, 70% of 60-
    year-old coal miners were impaired while only a third of the control 
    group were impaired. This would correspond to an excess risk of 37%.
        NIOSH also sponsored a study, conducted by Hopkinson (1981), on the 
    prevalence of middle ear disorders in coal miners. As part of this 
    study, the hearing acuity of 350 underground coal miners was measured. 
    The results of this study corroborated the results of the earlier NIOSH 
    study on the hearing acuity of underground coal miners. In both studies 
    the measured median hearing levels of the miners were the same. 
    However, the study did not present statistics on the percent of miners 
    incurring a hearing impairment nor the job classification of the 
    miners.
    
    Studies of Harm at Lower Sound Levels
    
        As our knowledge about the effects of noise increases, there is 
    increased need
    
    [[Page 66377]]
    
    to examine data that focuses on the harm that can occur at lower sound 
    levels. This section reviews some of the studies, particularly those of 
    workers from other countries, available in this regard.
        The most recent data are derived using the International Standards 
    Organization's publication ISO 1999 (1990). The information in that 
    publication can be used to calculate the mean and various percentages 
    of a population's hearing levels. The noise exposures for the 
    population can range between 75 dBA and 100 dBA. Table II-8 presents 
    the hearing level of a 60-year-old male exposed to noise for 40 years. 
    The noise induced hearing permanent threshold shift was combined with 
    presbycusis values to determine the total hearing loss. The presbycusis 
    values were those from an unscreened population. The unscreened 
    population is believed to more accurately represent the mining 
    population since people with nonoccupational hearing loss would not be 
    excluded from becoming miners.
    
             Table II-8.--Hearing Level for Selected Noise Exposures        
    ------------------------------------------------------------------------
                                                    Hearing level in dB     
                                             -------------------------------
               Sound Level in dBA               500    1000    2000    3000 
                                                Hz      Hz      Hz      Hz  
    ------------------------------------------------------------------------
    80......................................      12       6      10      30
    85......................................      12       6      11      33
    90......................................      12       6      16      42
    ------------------------------------------------------------------------
    
        Information about the effects on hearing of lower noise exposures 
    can be particularly valuable in directing attention to the possibility 
    of identifying subpopulations particularly sensitive to noise. The 
    Committee on Hearing, Bioacoustics, and Biomechanics of the National 
    Research Council (CHABA) (1993) reviewed the scientific literature on 
    hazardous exposure to noise. The report, reaffirming many of the 
    earlier findings of the Committee, suggests that exposures below 76 dBA 
    to 78 dBA are needed to prevent a NIHL based upon temporary threshold 
    shift (TTS) studies; moreover, the report suggests that the sound level 
    be less than 85 dBA, and possibly less than 80 dBA, to guard against 
    any permanent hearing loss at 4000 Hz based upon field studies. But of 
    particular interest is the suggestion that therapeutic drugs, such as 
    aminoglycoside antibiotics and salicylates, can interact 
    synergistically with noise to yield more hearing loss than would be 
    expected by either stressor. Given the increasing use of salicylates 
    (aspirin) in heart maintenance regimens, the potential synergistic 
    effect may warrant further study.
        Few current studies of unprotected U.S. workers exposed to a 
    TWA8 between 85 and 90 dBA are available because the OSHA hearing 
    conservation standard requires some protection at those levels for most 
    industries. The difficulty in constructing new retrospective studies of 
    U.S. workers has been noted by Kryter (1984) in his chapter on Noise-
    Induced Hearing Loss and Its Prediction. He believes that the 
    retrospective studies of Baughn, Burns and Robinson, and the U.S. 
    Public Health Service are the best available on the subject of NIPTS. 
    Regarding current retrospective studies he states:
    
        Furthermore, imposition of noise control and hearing 
    conservation programs in many industries in many countries over the 
    past 10 years or so make somewhat remote the possibility of 
    performing a meaningful retrospective study of the effects in 
    industry of noise on the unprotected ear.
    
        Kryter included a formula for deriving the effective noise exposure 
    level for damage to hearing. This was used to determine, from a 
    population of workers, NIPTS at different percentiles of sensitivity at 
    various audiometric test frequencies.
        Studies of workers from other countries can provide information of 
    particular value in assessing the consequences of workplace noise 
    exposure between 85 dBA and 90 dBA. MSHA has determined that while 
    differences in socioeconomic factors (e.g., recreational noise 
    exposure, use of ototoxic medicines, otitis media) make it difficult to 
    directly apply the results of studies of workers from other countries 
    to quantify the risk for U.S. workers, they can be used to establish 
    the existence of a risk in the 80 to 90 dBA range.
        Rop, Raber, and Fischer (1979) studied the hearing loss of 35,212 
    male and female workers in several Austrian industries, including 
    mining and quarrying. The researchers measured the hearing levels of 
    workers exposed to sound levels ranging from less than 80 dBA up to 115 
    dBA, and arranged them into eight study groups based upon average 
    exposures. They assumed that exposure to sound levels less than 80 dBA 
    did not cause any hearing loss and workers exposed to these levels were 
    assigned to the control group.
        Rop et al. reported that workers with 6 to 15 years of exposure at 
    85 dBA had significantly worse hearing than the control group. For the 
    five groups exposed between 80 dBA and 103.5 dBA, hearing loss tended 
    to increase steadily during their careers, but leveled off after 15 
    years. However, for workers exposed to sound levels above 103.5 dBA, 
    hearing loss continued to increase beyond 15 years.
        Using the data collected during the study, Rop et al. developed a 
    statistical method for predicting hearing loss. The researchers 
    predicted that 20.1% of the 55-year old males in the control group with 
    15 years of work experience would incur hearing loss. For a comparable 
    group of males with exposures at 85 dBA the risk increased to 41.6%; at 
    92 dBA the risk increased to 43.6%; and at 106.5 dBA the risk increased 
    to 72.3%. Rop et al. concluded that exposure to sound levels at or 
    above 85 dBA damaged workers' hearing.
        Schwetz et al. (1980) reported on a study of 25,000 Austrian 
    workers. The study concluded that the workers exposed to sound levels 
    between 85 dBA and 88 dBA experienced greater hearing loss than workers 
    exposed to sound levels less than 85 dBA. Because of this, Schwetz 
    recommended 85 dBA as the critical intensity (i.e., PEL). Furthermore, 
    the study concluded that a lack of hearing recovery occurs at 85 dBA 
    which is the ultimate cause of noise-induced hearing loss (NIHL).
        Stekelenburg (1982) calculated the hearing loss due to presbycusis 
    according to Spoor and due to noise according to Passchier-Vermeer. 
    Based upon these calculations, Stekelenburg suggested that 80 dBA be 
    the acceptable level for noise exposure over a 40 year work history. At 
    this exposure, Stekelenburg calculates that impaired social hearing due 
    to noise would be expected in 10% of the population.
        Bartsch et al. (1989) studied 537 textile workers. These 
    researchers defined hearing loss of social importance as a 40 dB 
    hearing level at 3000 Hz. The researchers found that hearing loss 
    resulting from exposures below 90 dBA mainly occurs at frequencies 
    above 8000 Hz (these frequencies are not normally tested during 
    conventional audiometry), and so concluded that this hearing loss was 
    not of ``social importance.'' Nevertheless, they recommended a hearing 
    loss risk criterion of 85 dBA be used to protect the workers' hearing.
        These results are generally consistent with those of U.S. workers. 
    MSHA would, however, note its disagreement with the characterization of 
    the amount of hearing loss not being of ``social importance'' as 
    expressed in the Bartsch et. al (1989) study. The Agency has concluded 
    that a person will encounter hearing difficulty before their hearing 
    level reaches 40 dB at 3000 Hz. Studies, discussed earlier in 
    Definition of Material Impairment, address the importance of having 
    good hearing
    
    [[Page 66378]]
    
    acuity at 3000 Hz in order to adequately understand speech in everyday 
    noisy environments.
    
    Reported Hearing Loss Among Miners
    
        To confirm the magnitude of the risks of NIHL among miners, MSHA 
    examined evidence of reported hearing loss among miners--audiometric 
    data collected over the years tracking hearing acuity among miners, the 
    comments received in response to the Agency's ANPRM, reports of hearing 
    loss by mine operators pursuant to 30 CFR part 50, and workers' 
    compensation data. Such data could provide a quantitative determination 
    of material impairment.
        With respect to audiometric data, MSHA asked NIOSH to examine a set 
    of data on coal miners. The analysis (Franks, 1996) supports the data 
    from scientific studies. It indicates that 90% of these coal miners 
    have a hearing impairment by age 50 as compared with only 10% of the 
    general population. Further, Franks stated that miners, after working 
    20 to 30 years, could find themselves in life threatening situations 
    since safety signals and ``roof talk'' could go unheard. (For the 
    purposes of the analysis, NIOSH used the definition of hearing 
    impairment it is now considering, an average 25 dB hearing level at 
    1000, 2000, 3000, and 4000 Hz; MSHA conducted its own analysis of the 
    data without the 4000 Hz, and the results are generally consistent with 
    those of NIOSH).
        This section also reviews several other sources of data that might 
    provide direct information about the risks of hearing loss to miners: 
    the comments received in response to the Agency's ANPRM, the reports of 
    hearing loss provided to the Agency by mine operators pursuant to 30 
    CFR part 50, and workers' compensation data. In each case, the 
    available data are too limited to draw any conclusions. The Agency is 
    requesting the public to provide further information along these lines.
    Audiometric Data Bases
        Audiometric testing is not currently required in metal and nonmetal 
    mining and is only required when an overexposure to noise is determined 
    in coal mining. Certain mining companies conduct routine audiometric 
    testing on their employees, but the results of these tests are 
    confidential and are not published for public use. In addition, summary 
    reports of these audiometric tests are generally not available.
        MSHA, however, has obtained an audiometric data base consisting of 
    20,021 audiograms conducted on 3,433 individual coal miners, in 
    connection with its ongoing efforts to assess the effectiveness of the 
    current standards in protecting miner health. The audiometric 
    evaluations were conducted between 1971 and 1994 with the bulk of the 
    audiograms conducted during the latter years.
        NIOSH (Franks, 1996) has analyzed this data base. Each audiogram 
    was reviewed for validity and NIOSH audiologists directly reviewed more 
    than 2,500 audiograms. The review reduced the number of audiograms by 
    8.8% and the number of miners by 8.3%.
        After deleting those audiograms judged to be invalid, NIOSH's 
    analysis indicates that 90% of these miners have a hearing impairment 
    by age 50 as compared with only 10% of the general population. Even at 
    age 69, only 50% of the non-noise exposed population acquire a hearing 
    impairment. Franks defined material impairment as an average 25 dB 
    hearing level at 1000, 2000, 3000, and 4000 Hz. This definition differs 
    from the MSHA definition of hearing impairment by the inclusion of 4000 
    Hz in the average.
        By age 35 the average miner has a mild hearing loss and 20% have a 
    moderate loss. By contrast, fewer than 20% of the miners having 
    marginally normal hearing by age 64 while the upper 80% have moderate 
    to profound hearing loss. The lower 80% of the non-noise exposed 
    population will not acquire a hearing loss as severe as the one 
    obtained by the average miner regardless of how long they live.
    
    BILLING CODE 4510-43-P
    [GRAPHIC] [TIFF OMITTED] TP17DE96.004
    
    
    
    [[Page 66379]]
    
    
    BILLING CODE 4510-43-C
    
        Further, Franks stated that miners, after working 20 to 30 years, 
    could find themselves in life threatening situations since safety 
    signal and roof talk could go unheard.
        MSHA separately conducted an elementary analysis of the data, using 
    the definition of material impairment of hearing used throughout the 
    analyses in this preamble: an average 25 dB hearing level at 1000, 2000 
    and 3000 Hz. For MSHA's analysis, all audiograms were considered to be 
    valid (e.g., no contamination from temporary threshold shifts, sinus 
    conditions, etc.). Information on years of mining experience, noise 
    exposure, use of hearing protectors, and job function was not provided.
        In order to reflect current trends, the percentage of current coal 
    miners with a material impairment of hearing was compared to historical 
    data (NIOSH's study on coal miners published in 1976). The audiometric 
    data were placed into a compatible format, e.g., age and hearing loss 
    criteria. Only those coal miners (2,861) whose latest audiogram was 
    taken between 1990 and 1994 were included in the analysis. The results 
    are shown in Chart R1 along with NIOSH's 1976 results for both the 
    noise exposed miners and the non-noise exposed controls.
    
    BILLING CODE 4510-43-P
    [GRAPHIC] [TIFF OMITTED] TP17DE96.005
    
    BILLING CODE 4510-43-C
    
    The data points for chart R1 are the mean of both ears at 1000, 2000 
    and 3000 Hz. The top line connects data points from the 1976 group, and 
    the middle line connects points from the 1990-1994 group; the bottom 
    line represents the non-noise exposed group.
        As shown in Chart R1, it is obvious that many coal miners who had 
    audiograms taken from 1990 through 1994 have a material impairment of 
    hearing. These miners were still losing more of their hearing acuity 
    than non-noise exposed workers. This remains true even if the analysis 
    is limited to miners less than 40 years of age (i.e., those who have 
    worked only under the current coal noise regulations). The fact that 
    the loss is at a slower rate than shown in the 1976 data may indicate 
    some progress under the existing regulations compared with no 
    regulation.
        Furthermore, MSHA analyzed the data for the number of standard 
    threshold shifts (STS's) and reportable hearing loss cases in order to 
    estimate the number of such events that may occur if the proposal is 
    adopted. In the proposal, MSHA defines an ``STS'' as a change in 
    hearing threshold level relative to the miner's original or 
    supplemental baseline audiogram of an average of 10 dB or more at 2000, 
    3000, and 4000 Hz in either ear. The importance of an STS is that it 
    reveals that a permanent loss in hearing acuity has occurred relative 
    to that miner's baseline. This is the type of loss that is deserving of 
    mine operator intervention. When the change from the baseline averages 
    25 dB or more at the same frequencies, the hearing loss must be 
    reported to MSHA so that the Agency can intervene if necessary. (MSHA 
    discusses the definition of STS and reportable hearing loss in detail 
    in the sections of this preamble dealing with proposed Secs. 62.160 and 
    62.190.) In both cases, the data differ from that in Chart R1, which is 
    looking at the hearing loss relative to audiometric zero--not the 
    individual miner's baseline.
        For a second analysis, the first audiogram was assumed to be the 
    baseline. The last audiogram was compared to the baseline. Neither 
    audiogram was corrected for presbycusis. Also, because of the lack of 
    supporting data, no provision for excluding an STS as being non-
    occupational was possible. A total of 3,102 coal miners had a baseline 
    and at least a second audiogram. However, only those miners whose 
    latest audiogram was conducted between 1990 and 1994 were considered. 
    The results are presented in Chart R2.
    
    BILLING CODE 4510-43-P
    
    [[Page 66380]]
    
    [GRAPHIC] [TIFF OMITTED] TP17DE96.006
    
    
    BILLING CODE 4510-43-C
    
        Chart R2 clearly shows that many of the coal miners from 1990 
    through 1994 were found to have an STS. The likelihood of acquiring an 
    STS generally increases with advancing age. The MSHA analysis was 
    conducted in a conservative fashion. Because the intervening audiograms 
    were excluded from this analysis, the number of STSs is probably low 
    since only a single STS was recorded. There could be several 
    explanations for the drop in the percentage of STS's for the 65 year 
    old age group in chart R2, including, for example, changed work 
    assignments.
        In addition to this privately maintained audiological data, there 
    have been two special NIOSH studies of the hearing acuity of coal 
    miners. These studies were reviewed in detail in the Risk of Impairment 
    section, above. The first study was published in 1976. Even though the 
    majority of noise exposures were found to be less than 90 dBA, 
    approximately 70% of the 60-year-old coal miners had a material 
    impairment of hearing using the OSHA/NIOSH definition. Another NIOSH 
    study, conducted by Hopkinson (1981), corroborated the results of the 
    earlier NIOSH study on the hearing acuity of coal miners.
    Commenter Data
        In its ANPRM, MSHA solicited comments on the number of current 
    miners with a hearing loss based on suggested criteria. Two commenters 
    provided information on the hearing acuity of miners. The first 
    commenter estimated that 45 to 50% of the employed miners have an STS 
    and at least 25% have an STS if corrected for presbycusis. Further, 
    this commenter estimated that about 25% of the miners have an average 
    hearing loss of 25 dB or more at 1000, 2000, and 3000 Hz. However, when 
    corrected for presbycusis, the percentage of miners with this level of 
    hearing loss decreased to about 15%.
        The second commenter referenced a paper presented by Smith et al. 
    at the 1989 Alabama Governor's Safety and Health Conference. This 
    commenter stated that Smith et al. reported on the evaluation of serial 
    audiograms from 100 workers exposed to sound levels less than 85 dBA. 
    Smith et al. had found that 15% of these workers would have some degree 
    of hearing impairment using AAO-HNS 1979 impairment criteria. Smith et 
    al. also reported that at least 26% of the mining population would have 
    some degree of hearing impairment using the same criteria. Smith (1994) 
    confirmed the prevalence of material impairment among miners in a 
    letter to MSHA.
        MSHA also requested information on hearing loss to individual 
    miners in its ANPRM. Specific information was requested on each miner 
    who had incurred a hearing loss, including the related noise exposure, 
    state workers' compensation award, cost of the award, miner's age, 
    occupation and degree of hearing loss. The Agency received few comments 
    pertaining to the information requested. The Agency requests additional 
    comment on these issues.
    Reported Hearing Loss Data
        Another potential body of information about hearing loss among 
    miners comes from reports mine operators are required to submit to MSHA 
    of such losses. At present, however, there is not a definition of 
    ``reportable hearing loss'' linking what is reported to some particular 
    measurement. Rather, under 30 CFR part 50, mine operators are only 
    required to report cases of NIHL to MSHA when it is diagnosed by a 
    physician or when the miner receives an award of compensation.
        Nevertheless, between 1985 and 1995 mine operators reported a total 
    of 2,402 cases of NIHL--and among these cases were a substantial number 
    of miners who began working at a mine after the implementation of the 
    current noise regulations.
        Coal mine operators reported 608 cases among surface miners, 1,077 
    cases among underground miners, and 14 cases among miners whose work 
    positions were not identified. According to coal mine operators, 662 of 
    the 1,699 cases began working at a mine after the implementation of 
    noise regulations for coal mines (1972 for underground and 1973 for 
    surface). Workers with no reported mining experience were excluded from 
    this analysis, because their noise exposure history in mining was 
    unknown.
        For the same period, metal and nonmetal mine operators reported 555 
    cases among surface miners and 148 cases among underground miners. 
    According to mine operators, 142 of the 703 cases began working at a 
    mine after the implementation of noise regulations for metal and 
    nonmetal mines (1975). As with the coal data, workers with no reported 
    mining experience were excluded.
    
    [[Page 66381]]
    
        Comparing the two types of mining, there were significantly more 
    reported hearing loss cases at coal mines than at metal and nonmetal 
    mines, and a higher proportion of those cases were to workers who began 
    working after the implementation of the current standards. This is 
    despite the fact that, at the present time, there are more metal and 
    nonmetal miners than coal miners employed in the U.S. A possible 
    explanation of the differences between reported cases of NIHL among 
    coal, metal and nonmetal miners may be the more frequent use of 
    engineering noise controls in metal and nonmetal mining.
        MSHA reviewed the narrative associated with each NIHL case to 
    determine the degree of hearing loss. Although many narratives 
    contained information as to the reason for reporting the NIHL case, 
    others only listed the illness as ``hearing loss.'' Approximately half 
    the cases had no information on the severity of the hearing loss. Some 
    narratives contained information on the severity of the hearing loss, 
    such as an STS, OSHA reportable case, or percent disability. Based upon 
    the information in the narratives it is not possible to determine an 
    average severity for the NIHL cases.
        However, at least 40% of the cases in coal mining were reported to 
    MSHA as the result of the miner being compensated for NIHL. Another 7% 
    of the cases filed a workers' compensation claim for NIHL. In metal and 
    nonmetal, at least 19% of the cases were the result of the miner being 
    compensated for NIHL. Nearly another 3% of the cases filed a workers' 
    compensation claim for NIHL.
        MSHA contends that the number of cases reported to the Agency are 
    low because of the following factors: the lack of a specific definition 
    of a NIHL in MSHA's part 50 regulations which may result in confusion 
    on the part of mine operators about which cases to report; the lack of 
    consistency among the states' requirements for awarding compensation 
    for an NIHL and among physicians in diagnosing what constitutes a 
    hearing loss caused by noise; and the lack of periodic audiometric 
    testing in the mining industry.
        In summary, current hearing loss reported to MSHA under part 50 
    cannot be used to accurately characterize the incidence, prevalence or 
    the severity of hearing loss in the mining industry. However, the part 
    50 data clearly show that miners are incurring NIHL.
    Workers' Compensation Data
        Another source of information about hearing loss among miners is 
    state workers' compensation agencies and insurance carriers. Many 
    states do not keep detailed workers' compensation data themselves; 
    categorization of data are inconsistent across the states; and there 
    are privacy concerns in obtaining the detailed information needed for 
    studies. MSHA would welcome information about studies of hearing loss 
    that have been performed by the insurance industry or others based on 
    this data.
        Valoski (1994) studied the number of miners receiving workers' 
    compensation and the associated indemnity costs of those awards. 
    Despite contacting each state workers' compensation Agency and using 
    two national data bases, he was unable to obtain data for all states. 
    In fact, data were not available from a number of key mining states.
        From the data that were available for study, Valoski reported that 
    between 1981 and 1985 at least 2,102 coal miners and 312 metal and 
    nonmetal miners were awarded compensation for occupational hearing 
    loss. The identified total indemnity costs of those awards exceeded 
    12.5 million dollars excluding rehabilitation or medical costs.
        In Niemeier's letter to MSHA, Chan et al. of NIOSH (1995) 
    investigated the incidence of NIHL among miners using information from 
    the Bureau of Labor Statistics' (BLS) Supplementary Data System. Like 
    Valoski, he found the national data to be incomplete. Only 15 states 
    participated in the BLS program between 1984 and 1988. In these 15 
    states, a total of 217 miners (93 coal miners and 124 metal and 
    nonmetal miners) were awarded workers' compensation for NIHL. Chan et 
    al. stated that because of differing state workers' compensation 
    requirements, it is not possible to directly compare NIHL among the 
    states. These factors limit the usefulness of the obtained data.
        MSHA also reviewed reports on workers' compensation in Canada and 
    Australia. The noise regulations and mining equipment used in these 
    countries are similar to those in the U.S. A recent report on workers' 
    compensation awards to miners in Ontario, Canada (1991) revealed that 
    between 1985 and 1989, NIHL was the second leading compensable 
    occupational disease. Approximately 250 claims for NIHL involving 
    miners were awarded annually during that time.
        Lescouflair et al. (1980) studied 278 metal and asbestos miners in 
    Quebec, Canada, who claimed compensation for hearing loss. Of the 278 
    cases, 28.7% (80) were excluded as cases of non-mining NIHL. 
    Approximately 50% (99) of those remaining cases diagnosed as having 
    NIHL were shown to have a hearing impairment based upon the AAOO 1959 
    criteria and an estimated 63% (125) showed an impairment based upon 
    AAO-HNS 1979 criteria. The miners were exposed to noise for 15 to 49 
    years and showed a similar occurrence of hearing loss in both surface 
    and underground occupations. The researchers also reported that there 
    was no significant difference in NIHL among the miners for those 
    subjects exposed to a mixture of intermittent-continuous noise versus 
    intermittent noise except at 2000 Hz.
        Eden (1993) reported on the Australian mining industry's experience 
    with hearing conservation. Eden quoted statistics from the Joint Coal 
    Board which revealed that NIHL comprised 59% to 80% of the reported 
    occupational diseases from 1982 to 1992. Eden also reported that in New 
    South Wales 474 of 16,789 coal miners were awarded compensation for 
    NIHL. The incidence rate for the total mining industry in New South 
    Wales was about 23 cases per 1,000 workers during 1990-1991. This was 
    the highest rate for any industry in New South Wales.
        In conclusion, like reported cases of NIHL, the compensation data 
    are too incomplete to be used for quantitative estimates of the 
    prevalence of NIHL in the mining industry. But like the reported case 
    data, the compensation data that are available do show that numerous 
    cases are still being filed each year at considerable cost. Further, 
    according to the data reported by mine operators, many miners who 
    developed NIHL only worked in mining after the implementation of the 
    current noise regulations. While limited, this evidence of continued 
    risk supplements and supports the data previously presented from 
    scientific studies.
        The Agency would welcome the submission of additional data to 
    supplement that which it has been able to gather to date.
    
    Exposures in the U.S. Mining Industry
    
        In this section MSHA presents information on noise exposure in the 
    U.S. mining industry, so as to develop a picture of the mining 
    population at a significant risk of incurring material impairment as a 
    result of that exposure. The exposure levels are particularly high in 
    the coal industry, where hearing protectors, rather than engineering or 
    administrative controls, remain the primary means of miner protection 
    against NIHL. But the data indicate that exposure levels remain high in 
    all sectors of the mining industry even
    
    [[Page 66382]]
    
    though noise regulations have been implemented for some time.
    Inspection Data
        The first presentation, Tables II-9 and II-10, reviews noise 
    exposure data collected by MSHA inspectors from thousands of samples 
    gathered over many years to check compliance with the current permitted 
    levels. Because the proposed rule would alter the way a miner's noise 
    dose is calculated in one respect, MSHA conducted a special survey to 
    obtain data that would reflect this change. The data are presented in 
    Tables II-11 and II-12. The survey data are also presented by 
    occupation in Tables II-13 and II-14. All the readings are in time-
    weighted 8-hour averages.
        Tables II-9 and II-10 display samples which present readings 
    exceeding the permissible exposure limit, a TWA8 of 90 dBA.
        Table II-9 shows noise dose trends in metal and nonmetal mines 
    based on over 232,500 full-shift samples collected by MSHA from 1974 
    through 1995 using personal noise dosimeters.
    
        Table II-9.--Metal and Nonmetal Noise Dose Trends 1974 to 1995 a    
    ------------------------------------------------------------------------
                                                                    Percent 
                                             Number of  Number of      of   
                      Year                    samples   samples >  samples >
                                                          90 dBA     90 dBA 
    ------------------------------------------------------------------------
    1974...................................        363        139       38.3
    1975...................................      3,826      1,661       43.4
    1976...................................      9,164      3,725       40.6
    1977...................................     13,485      5,047       37.4
    1978...................................     17,326      6,415       37.0
    1979...................................     21,176      7,638       36.1
    1980...................................     15,185      5,203       34.3
    1981...................................     11,278      3,651       32.4
    1982...................................      3,208        876       27.3
    1983...................................      7,628      2,188       28.7
    1984...................................      8,525      2,311       27.1
    1985...................................      8,040      2,094       26.0
    1986...................................      9,213      2,402       26.1
    1987...................................     10,145      2,818       27.8
    1988...................................     10,514      2,417       23.0
    1989...................................     10,279      2,208       21.5
    1990...................................     13,067      2,721       20.8
    1991...................................     14,936      2,947       19.7
    1992...................................     14,622      2,809       19.2
    1993...................................     14,566      2,529       17.4
    1994...................................     15,979      2,627       16.4
    1995...................................     13,865      1,989      14.4 
    ------------------------------------------------------------------------
    a Data from USBOM' MIDAS data base.                                     
    
        Table II-10 below presents noise dose trends in coal mines based on 
    75,691 full-shift samples collected by MSHA from 1986 through 1995 
    using personal noise dosimeters. MSHA actually began routine sampling 
    in coal mines in 1978; however, its data base did not begin until 1986.
    
      Table II-10.--Coal Mine Noise Dose Trends, Fiscal Years 1986 to 1995  
    ------------------------------------------------------------------------
                                                                     Percent
                                             Number of  Number of      of   
                  Fiscal year                 samples    samples    samples 
                                                         >90 dBA    >90 dBA 
    ------------------------------------------------------------------------
    1986...................................      2,037        593       29.1
    1987...................................     12,774      3,314       25.9
    1988...................................     11,888      2,702       22.7
    1989...................................     11,035      2,313       21.0
    1990...................................     10,861      2,388       22.0
    1991...................................      6,898      1,635       23.7
    1992...................................      6,636      1,660       25.0
    1993...................................      7,223      1,908       26.4
    1994...................................      6,339      1,656       26.1
    1995...................................      5,407      1,219       22.5
    ------------------------------------------------------------------------
    
        The inspection data for the two sectors have also been graphed in 
    charts II-9 and II-10 for years in which MSHA collected data for both 
    sectors.
        As illustrated by the charts, the metal and nonmetal sector shows a 
    gradual, but consistent, downward trend in the percent of samples 
    exceeding the current PEL. However, there was no such clear trend for 
    coal mines during the same time period. (It should be noted that while 
    the data points on these 3-D graphs come from the last column of the 
    tables, the shading may make them seem somewhat lower than they are in 
    fact.)
    
    BILLING CODE 4510-43-P
    
    [[Page 66383]]
    
    [GRAPHIC] [TIFF OMITTED] TP17DE96.007
    
    
    BILLING CODE 4510-43-C
    
    [[Page 66384]]
    
        There are several factors which must be considered when drawing any 
    conclusions from the data. MSHA sampling may be biased towards noisier 
    mines and occupations. Additionally, when an overexposure is found 
    during an initial survey, the data base includes both the initial 
    overexposure and the results of any resampling to determine compliance 
    after the mine operator has utilized engineering and/or administrative 
    controls. While these biases may tend to offset each other, their 
    specific impact cannot be quantified. These factors should, however, 
    impact both sectors roughly equally.
    Dual Survey Data
        MSHA has concluded that the information contained in Tables II-9 
    and II-10 understates the actual noise exposures in the industry 
    because the information was collected using a 90 dBA threshold level, 
    i.e. sound levels of less than 90 dBA are not integrated into the 
    results. As discussed later in part III of the preamble, in connection 
    with proposed Sec. 62.120(a), MSHA is proposing to change the threshold 
    level to integrate sound levels of between 80 dBA and 130 dBA because 
    MSHA has concluded that this is warranted by the weight of scientific 
    evidence. Integrating the sound levels between 80 dBA and 90 dBA into 
    the noise exposure will generally increase the measured noise dose. The 
    greater the amount of noise between 80 dBA and 90 dBA the greater the 
    impact on the measured noise dose.
         Accordingly, MSHA conducted a special survey to compare noise 
    exposures at different threshold levels. The survey, referred to 
    hereinafter as the ``dual-threshold'' survey, involved the collection 
    of personal noise dosimeter data by MSHA inspectors in coal mines and 
    metal and nonmetal mines. Each sample was collected using a personal 
    noise dosimeter with the capability of simultaneously collecting data 
    at both a 90 dBA threshold and an 80 dBA threshold. All other dosimeter 
    settings were the same as those used during normal compliance 
    inspections (the 90 dB criterion level, 5-dB exchange rate, and A-
    weighting system which are not now being proposed by MSHA for change). 
    The noise doses were mathematically converted to the appropriate 
    TWA8 using different criterion levels and threshold values.
        Tables II-11 and II-12 display the dual-threshold data: 
    respectively in metal and nonmetal mines, and in coal mines. Table II-
    11 specifically shows the dual-threshold data collected for metal and 
    nonmetal mines from March 1991 through December 1994 using personal 
    noise dosimeters. This data consisted of more than 42,000 full-shift 
    samples.
    
      Table II-11.--M/NM Dual Threshold Samples at or Exceeding Specified TWA8 Sound Levels from March 1991 Through 
                                                      December 1994                                                 
    ----------------------------------------------------------------------------------------------------------------
                                                                      90 dBA thresholds         80 dBA threshold    
                                                                 ---------------------------------------------------
                      TWA8 Sound Level (in dBA)                    Number of    Percent of   Number of    Percent of
                                                                    samples      samples      samples      samples  
    ----------------------------------------------------------------------------------------------------------------
    90..........................................................        7,360         17.4       11,150         26.5
    85..........................................................  ...........  ...........       28,250         66.9
    ----------------------------------------------------------------------------------------------------------------
    
        Note: Two of the boxes in the table do not contain entries. This 
    is to avoid the potential for making an inappropriate comparison of 
    values. Direct comparison of TWA8 values determined with 
    different thresholds is not appropriate if the TWA8 is less 
    than one of the thresholds. An example may help to illustrate the 
    point. A miner exposed to a constant sound field of 85 dBA for 8 
    hours would be determined to have a noise dose of 0%, or a TWA8 
    of 0 dBA, if a 90 dBA threshold is used: none of the sound would be 
    counted in the computation. If the exposure was measured using an 80 
    dBA threshold, the dose would be 50%, or a TWA8 of 85 dBA. 
    Contrasting the measures taken with the two thresholds would be 
    inappropriate in such a case.
    
        As indicated in Table II-11, 17.4% of all samples collected by MSHA 
    in metal and nonmetal mines during the specified time period equaled or 
    exceeded a TWA8 of 90 dBA using a 90 dBA threshold--slightly less 
    than the results of inspector sampling in Table II-9. In these 
    instances, engineering and/or administrative controls were required to 
    be implemented in the metal or nonmetal mines to reduce sound levels to 
    the PEL: a requirement that would be retained under the proposed rule. 
    When sound levels between 80 dBA and 90 dBA are taken into account, 
    however, 26.4% of the readings indicated non-compliance. Thus, changing 
    the threshold to properly reflect harmful sound levels indicates 
    harmful noise exposures in this industry are more significant than 
    revealed by the inspection data in Table II-9. Furthermore, 67% of the 
    samples in metal and nonmetal mines exceeded a TWA8 of 85 dBA 
    using an 80 dBA threshold.
        MSHA dual-threshold sampling data for coal mines is presented in 
    Table II-12. This data consists of over 4,200 full-shift samples 
    collected from March 1991 through December 1995 using personal noise 
    dosimeters.
    
       Table II-12.--MSHA Coal Dual Threshold Samples at or Exceeding Specified TWA8 Sound Levels from March 1991   
                                                  Through December 1995                                             
    ----------------------------------------------------------------------------------------------------------------
                                                                      90 dBA threshold          80 dBA threshold    
                                                                 ---------------------------------------------------
                      TWA8 Sound Level (in dBA)                    Number of    Percent of   Number of    Percent of
                                                                    samples      samples      samples      samples  
    ----------------------------------------------------------------------------------------------------------------
    90..........................................................        1,075         25.3        1,510         35.6
    85..........................................................  ...........  ...........        3,268         76.9
    ----------------------------------------------------------------------------------------------------------------
    
        As indicated in Table II-12, 25.3% of all samples collected by MSHA 
    in coal mines during the specified time period equaled or exceeded a 
    TWA8 of 90 dBA using a 90 dBA threshold. This percentage increases 
    to 35.6% when an 80 dBA threshold is used. Furthermore, using an 80 dBA 
    threshold, almost 77% of the survey samples from the coal
    
    [[Page 66385]]
    
    industry showed noise exposures equaling or exceeding 85 dBA.
        Tables II-13 and II-14 present some of the MSHA dual-threshold 
    sampling data by occupation for the most frequently sampled occupations 
    in metal and nonmetal mines and coal mines, respectively. A note of 
    caution: the only data presented in these tables is 90 threshold data 
    at a TWA8 of 90, and 80 threshold data at a TWA8 of 85. 
    Accordingly, the columns should not be compared. Perhaps the best way 
    to think of this presentation is as two independent analyses at how the 
    exposure levels of various job categories compare with each other.
    
     Table II-13.--Percentage of MSHA M/NM Samples a by Selected Occupation,
                      Exceeding Specified TWA8 Sound Levels                 
    ------------------------------------------------------------------------
                                                       90 dBA       80 dBA  
                                                     threshold    Threshold 
                                        Number of  -------------------------
                Occupation               samples     Percent of   Percent of
                                                     samples >    samples > 
                                                       90 dBA       85 dba  
    ------------------------------------------------------------------------
    Front-end-loader operator........       12,812         12.9         67.7
    Truck driver.....................        6,216         13.1         73.7
    Crusher operator.................        5,357         19.9         65.1
    Bulldozer operator...............        1,440         50.7         86.2
    Bagger...........................        1,308         10.2         65.0
    Sizing/washing plant operator....        1,246         13.2         59.7
    Dredge/barge attendant...........        1,124         27.2         78.7
    Clean-up person..................          927         19.3         71.3
    Dry screen operator..............          871         11.7         57.6
    Utility worker...................          846         12.4         60.6
    Mechanic.........................          761          3.8         43.9
    Supervisors/administrators.......          730          9.0         32.2
    Laborer..........................          642         17.1         65.7
    Dragline operator................          583         34.0         82.5
    Backhoe operator.................          546          8.4         52.6
    Dryer/kiln operator..............          517         10.5         55.5
    Rotary drill operator (electric/                                        
     hydraulic)......................          543         39.6         83.1
    Rotary drill operator (pneumatic)          489         64.4        89.0 
    ------------------------------------------------------------------------
    a These occupations comprise about 87 percent of the 42,206 MSHA dual-  
      threshold samples collected in metal and nonmetal mines from March    
      1991 through December 1994. All samples were collected using a        
      personal noise dosimeter over a miner's full-shift.                   
    
    
     Table II-14.--Percentage of MSHA Coal Samples by Occupation, Exceeding 
                          Specified TWA8 Sound Levelsa                      
    ------------------------------------------------------------------------
                                                       90 dBA       80 dBA  
                                                     threshold    threshold 
                                        Number of  -------------------------
                Occupation               samples     Percent of   Percent of
                                                     samples >    samples > 
                                                       90 dBA       85 dBA  
    ------------------------------------------------------------------------
    Continuous miner helper..........           68         33.8         88.2
    Continuous miner operator........          262         49.6         96.2
    Roof bolter operator (single)....          234         21.8         85.5
    Roof bolter operator (twin)......           92         31.5         98.9
    shuttle car operator.............          260         13.5         78.5
    Scoop car operator...............           94         18.1         74.5
    Cutting machine operator.........           22         36.4         63.6
    Headgate operator................           20         40.0        100.0
    Longwall operator................           34         70.6        100.0
    Jack setter (longwall)...........           25         32.0         68.0
    Cleaning plant operator..........          107         36.4         77.6
    Bulldozer operator...............          225         48.9         94.2
    Front-end-loader operator........          244         16.0         76.6
    Highwall drill operator..........           83         21.7         77.1
    Refuse/backfill truck driver.....          162         13.6         78.4
    Coal truck driver................           28         17.9        64.3 
    ------------------------------------------------------------------------
    a Above sampled occupations comprise about 71.0% of the 4,247 MSHA dual 
      threshold samples collected in coal mines from March 1991 to December 
      1995. All samples were collected using a personal noise dosimeter over
      a miner's fullshift.                                                  
    
        As shown in these tables, the percentage of miners exceeding the 
    specified sound levels varied greatly according to occupation. For 
    example, Table II-13 shows that only 8.4% of the backhoe operators in 
    metal and nonmetal mines had noise exposures exceeding a TWA8 of 
    90 dBA using a 90 dBA threshold, while 64.4% of the pneumatic rotary 
    drill operators had similar exposures. When reviewing the same two 
    occupations, 52.6% of the backhoe operators and 89.0% of the pneumatic 
    rotary drill operators would have noise exposures exceeding a TWA8 
    of 85 dBA using an 80 dBA threshold.
    
    [[Page 66386]]
    
    Conclusion; Miners at Significant Risk of Material Impairment
    
        MSHA has prepared an exposure profile of miners based on the data 
    presented in this part; the methodology is summarized in the following 
    paragraphs and described in detail in the Agency's preliminary RIA. 
    Based on this profile, MSHA has concluded that despite many years under 
    existing standards, noise exposures in all sectors of mining continue 
    to pose a significant risk of material impairment to miners over a 
    working lifetime.
        Specifically, MSHA estimates that 15% of coal miners will incur a 
    material impairment of hearing under present exposure conditions, or 
    18,947 coal miners. The figures are 13% of metal and non-metal miners 
    (26,977 metal and nonmetal miners) and 14% of miners as a group (45,924 
    miners). (The figures include contract miners but exclude certain 
    office workers.)
        To derive this information, MSHA began with the 80 dBA exposure 
    data discussed in the prior section. The sampling data were sorted by 
    exposure range: e.g., samples with a TWA8 of between 80-84.9 dBA, 
    those between 85-89.9 dBA, those between 90-94.9 dBA, and so on.
        The sampling data were then adjusted by subtracting 5 dBA from the 
    exposure readings for all samples that had a TWA8 of 90 dBA at the 
    90 threshold. These are the samples that would be above the current 
    PEL. MSHA assumed that mine operators currently issue personal HPDs to 
    miners exposed at or above the PEL, that miners are using the HPDs, and 
    that such protection reduces the miner's equivalent TWA8 noise 
    exposure by about 5 dBA. (There is an extended discussion in part III 
    of this preamble about hearing protector effectiveness, and appropriate 
    references, that shed further light on these assumptions.)
        Then the percentage of adjusted samples within each range was 
    multiplied by MSHA's estimates of the total number of mine employees. 
    Those estimates are based on information gathered by the former USBOM 
    (and are presented in part IV of this preamble as part of the Agency's 
    industry profile).
        Finally, to establish the number of miners expected to incur a 
    material impairment of hearing, the Agency multiplied the number of 
    miners in each exposure range by the risk of impairment of exposure at 
    that range for a lifetime. For this purpose, the Agency used the 1972 
    NIOSH risk estimates discussed earlier in this part. (The Agency is 
    aware that NIOSH is currently working on revising its estimates using a 
    different model and taking hearing loss at an additional frequency into 
    account; but until such an approach is peer reviewed, MSHA has 
    concluded it should rely upon the 1972 estimates.)
        Based on these assumptions, Table II-15 presents MSHA's profile of 
    the projected number of miners currently at significant risk of 
    developing a material impairment of NIHL under existing exposure 
    conditions.
    
                    Table II-15.--Projected Number of Miners Likely To Incur NIHL Impairment under Existing Standards and Exposure Conditions               
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       <80 80-84.9="" 85-89.9="" 90-94.9="" 95-99.9="" 100-104.99="">105     Total*  
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    Coal.........................................            0          599       11,956        5,622          643          111             16        18,947
    M/NM.........................................            0        1,225       16,910        7,580        1,190           62             10        26,977
                                                  ----------------------------------------------------------------------------------------------------------
        Total *..................................            0        1,825       28,866       13,201        1,833          173             26       45,924 
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    * Includes contractor employees. Does not include office workers. Discrepancies are due to rounding.                                                    
    
        When MSHA promulgated noise standards in 1971 for underground coal 
    mines, in 1972 for surface coal mines, and in 1974 for metal and 
    nonmetal mines, compliance with the requirements was thought to be 
    adequate to prevent the occurrence of NIHL in the mining industry. 
    Since that time, however, there have been numerous awards of 
    compensation for hearing loss among miners.
        Moreover, MSHA's requirements are dated in light of the Agency's 
    experience, that of other domestic and foreign regulatory agencies, and 
    the recommendations of experts on what it takes to have an effective 
    prevention program. NIOSH, for example, currently recommends a 
    comprehensive program which includes the institution of an HCP to 
    prevent NIHL; MSHA's current standards do not include such protection.
        In light of current scientific evidence demonstrating that NIHL 
    constitutes a serious hazard, the evidence of continuing harm to 
    miners, and the fact that MSHA standards no longer reflect experience 
    and expert advice, MSHA has concluded that there is a need to replace 
    its existing noise standards with new standards that would provide 
    additional protection to miners. Section 101(a)(6)(A) of the Federal 
    Mine Safety and Health Act of 1977 (Mine Act), states that MSHA's 
    promulgation of health standards must:
    
    * * * [A]dequately assure on the basis of the best available 
    evidence that no miner will suffer material impairment of health or 
    functional capacity even if such miner has regular exposure to the 
    hazards dealt with by such standard for the period of his working 
    life.
    
    Significant NIHL clearly is the type of material impairment of health, 
    which Congress has directed the Secretary of Labor (Secretary) to 
    prevent. MSHA has concluded that the new requirements in this proposal 
    are necessary to prevent large numbers of miners from suffering 
    material impairment of health resulting from exposure to noise. 
    Compliance will reduce NIHL among miners and the costs associated 
    therewith.
        Based on these studies and MSHA's own calculations and analysis 
    presented above, the Agency has concluded that regulatory action is 
    necessary to address the continued excess risk of NIHL resulting from 
    mining employment.
    
    III. Discussion of Proposed Rule
    
    Summary
    
        This part of the Supplementary Information reviews the provisions 
    of the proposed rule, along with the information, comments and 
    alternatives considered by MSHA in developing each feature of the 
    proposal.
        While the Agency is seeking to present a complete picture of the 
    basis for its preliminary decisions, so as to facilitate comment, space 
    considerations preclude a full presentation of all of the sources 
    reviewed by the Agency. Part V is a complete reference list of those 
    sources. Among other things, part V contains a list of publications by 
    the former USBOM that were reviewed by the Agency. Many of these 
    describe methods for controlling noise for particular types of mining 
    equipment or facilities, and thus supplement the discussion in this 
    part about feasible engineering controls. All constitute part of the 
    Agency's rulemaking record.
    
    [[Page 66387]]
    
        In addition to the materials cited in part V, the Agency researched 
    the noise regulatory codes of a number of other jurisdictions--
    including those of the military and of other countries. While these 
    codes are noted in this part in a few summary tables, and discussed in 
    connection with certain key requirements being proposed by the Agency, 
    the Agency has determined there is no need to elucidate their 
    requirements in each and every section of this part. Nevertheless, 
    these codes also constitute part of the Agency's rulemaking record.
    
    Section 62.100  Purpose and Scope; Effective Date
    
    Purpose
    
        The purpose of the standards in proposed part 62 is the prevention 
    of occupational noise-induced hearing loss among miners. It is 
    important to clearly state the purpose of the regulations: to clarify 
    it to the regulated public and Agency personnel, and so that the 
    effectiveness of the regulations over time can be measured consistent 
    with principles under the Government Performance Results Act.
    Scope
        Part 62 would set forth health standards for all coal, metal and 
    nonmetal mines, both surface and underground, subject to the Federal 
    Mine Safety and Health Act of 1977. MSHA currently has four sets of 
    noise standards: for surface metal and nonmetal mines (30 CFR 56.5050), 
    for underground metal and nonmetal mines (30 CFR 57.5050), for 
    underground coal mines (30 CFR part 70, subpart F), and for surface 
    coal mines and surface work areas of underground coal mines (30 CFR 
    part 71, subpart I). In fact, however, there are really two groups of 
    standards: those applicable to coal mines and those applicable to metal 
    and nonmetal mines. This is because the surface and underground 
    standards for noise in metal and nonmetal mines are identical; the same 
    is true of the surface and underground standards for noise in coal 
    mines. The differences between the standards applicable in the coal 
    industry and in other mining industries are discussed in detail in the 
    following pages.
        Part 62 would establish a single, uniform noise standard applicable 
    to all mines. This approach is favored by many. Those who responded to 
    MSHA's ANPRM generally agreed that consolidation and simplification of 
    multiple standards into one may help to facilitate understanding of, 
    and thus compliance with, regulatory requirements. Such an approach is 
    also traditional with noise: OSHA's standards apply uniformly to 
    hundreds of industries.
        The proposed standard is not identical to the existing coal 
    standard nor to the existing metal and nonmetal standard. Nor is the 
    proposal identical to the noise standard which has been applicable to 
    most other industries since 1983 pursuant to the Occupational Safety 
    and Health Act (29 CFR 1910.95). Conditions in the mining industry, 
    experience with the current standards, MSHA's review of the latest 
    scientific information, the comments submitted in response to the 
    ANPRM, and the requirements of the Mine Safety and Health Act have led 
    the Agency to propose a standard that is unique in some respects. 
    Nevertheless, many key features in the proposal are identical to 
    features in one or more of the existing noise standards.
        Several charts comparing the features of the proposed standard to 
    the features of existing MSHA and OSHA noise standards are included in 
    the ``Question and Answers'' in part I of the Supplementary Information 
    accompanying this notice.
    Effective Date
        MSHA recognizes that successful implementation of these new and 
    uniform health rules will require new training of MSHA personnel and 
    guidance to employees and mine operators, particularly small mine 
    operators. Accordingly the Agency is proposing that the new standards 
    take effect one year after the date of publication of the final rule. 
    An alternative would be to phase in the new requirements. The Agency 
    believes some could be phased in quickly, but wants to avoid confusion. 
    The Agency requests comment on whether a phased-in approach is 
    appropriate and how it might most effectively be designed.
    
    Section 62.110  Definitions
    
        The proposal would include some definitions to facilitate 
    understanding.
        The definitions include some technical terms universally used in 
    noise measurement, e.g., criterion level.
        The definitions also include some terms used in the mining industry 
    in a way that differs from usage in other contexts, e.g., usage under 
    the OSHA standard. One example is the term ``hearing conservation 
    program'' or ``HCP.'' Under the proposal, requirements for hearing 
    protectors and training are not always linked to audiometric testing 
    results as they are under the OSHA standard. To avoid confusion, the 
    proposal defines a hearing conservation program as a generic reference 
    to those sections of the proposal that set forth the requirements for 
    an audiometric testing program. Another example is the definition of 
    ``qualified technician''.
        The definitions also include some terms which are non-standard. In 
    particular, the Agency is proposing to use the term ``supplemental 
    baseline audiogram'' instead of the more commonly used ``revised 
    audiogram''; MSHA believes its terminology will make it easier for the 
    mining industry to understand the requirements of the proposal.
        The discussion which immediately follows summarizes the salient 
    features of the definitions. A more detailed discussion of the 
    definitions is contained in those sections of the preamble which review 
    the context in which each definition is to be used.
    Access
        Access is the right to examine and copy records. This is consistent 
    with the use of this term in several of MSHA's and OSHA's existing 
    health standards.
    Audiologist
        A professional, specializing in the study and rehabilitation of 
    hearing, who is certified by the American Speech-Language-Hearing 
    Association or licensed by a state board of examiners. MSHA has 
    included this definition primarily to indicate which organizations 
    certify or license audiologists. MSHA has decided that all practicing 
    audiologists should be either licensed or certified by one or both of 
    the above organizations. This term is considered in the section of this 
    preamble that discusses proposed Sec. 62.140 Audiometric testing 
    program.
    Baseline Audiogram
        The audiogram against which future audiograms are usually compared. 
    By comparing an annual audiogram to the baseline audiogram the 
    progression of noise-induced hearing loss can be determined. This term 
    is considered in the section of this preamble that discusses proposed 
    Sec. 62.140, Audiometric testing program.
    Criterion Level
        This refers to the sound level which if applied for 8 hours results 
    in a dose of 100% of that permitted by the standard. Under proposed 
    Sec. 62.120(a), the criterion level would be a sound level of 90 dBA. 
    If applied for 8 hours, this sound level would result in a dose of 100% 
    of the permissible exposure limit (PEL), established by proposed 
    Sec. 62.120(c) as an 8-hour-time-weighted average of 90 dBA. The PEL 
    and the
    
    [[Page 66388]]
    
    criterion level are not the same thing. While the PEL is a sound level 
    of 90 dBA for 8 hours, it is also a sound level of 95 dBA for 4 hours; 
    the criterion level is always a constant, derived from what the PEL is 
    at 8 hours of exposure.
    Decibel (dB)
        Unit of measurement of sound. Decibel is used to describe 
    environmental/occupational sounds and hearing acuity.
    Decibel, A-weighted (dBA)
        Sound levels measured using the A-weighting network. There are 
    several frequency response networks which have been developed, as noted 
    in the section of the preamble discussing proposed Sec. 62.120(a). A-
    weighting refers to the frequency response network closely 
    corresponding to the frequency response of the human ear. This network 
    attenuates sound energy in the upper and lower frequencies (<1000 and="">5000 Hz) and slightly amplifies those frequencies between 1000 and 
    5000 Hz. The characteristics of the A-weighting network are found in 
    ANSI S1.25-1991, ``Specification for Personal Noise Dosimeters''.
    Designated Representative
        A designated representative is an individual or organization to 
    whom a miner gives written authorization to exercise a right of access 
    to records, pursuant to proposed Sec. 62.200.
    Exchange Rate
        The amount of increase or decrease in sound level which would 
    require halving or doubling the allowable exposure time to maintain the 
    same noise dose. In this proposal, a 5-dBA increase in the sound level 
    would correspond to a halving of the allowable exposure time. Exchange 
    rate is discussed in detail in the section of this preamble discussing 
    proposed Sec. 62.120 Noise exposure levels.
    Hearing Conservation Program (HCP)
        An HCP is designed to detect early changes in a miner's hearing 
    acuity so that corrective action can be instituted to minimize future 
    hearing loss. In general parlance, an HCP is a system of audiological 
    examinations that provide guidance for the use of hearing protectors, 
    other controls, and training. In the proposed rule, however, hearing 
    protector use and training linked to audiological examinations are only 
    a limited subset of the hearing protector and training requirements. 
    Accordingly, to avoid confusion, the term ``hearing conservation 
    program'' in the proposed rule is defined as a generic reference to the 
    requirements of Secs. 62.140 through 62.190 of part 62, the 
    requirements dealing with audiological examinations and the corrective 
    actions linked thereto.
    Hearing Protector
        The purpose of this definition is to clarify that not all devices 
    or materials inserted in or that cover the ear to reduce the noise 
    exposure can qualify as a hearing protector. For example, MSHA does not 
    consider a hearing aid as a hearing protector.
        A hearing protector must meet two requirements. First, to be a 
    hearing protector a device must be sold wholly or in part on the basis 
    of its ability to reduce the level of sound entering the ear. Thus, 
    cotton would not be an acceptable hearing protector. Second, the device 
    must have a scientifically accepted indicator of noise reduction value.
        MSHA's definition encompasses that used in the Environmental 
    Protection Agency's (EPA) labeling standards for hearing protectors (40 
    CFR Sec. 211.203(m)). The EPA defines a hearing protector as:
    
    * * * any device or material, capable of being worn on the head or 
    in the ear canal, that is sold wholly or in part on the basis of its 
    ability to reduce the level of sound entering the ear. This includes 
    devices of which hearing protection may not be the primary function, 
    but which are nonetheless sold partially as providing hearing 
    protection to the user.
    
        EPA requires that all hearing protector manufacturers include 
    labeling information with their products that indicate their Noise 
    Reduction Rating (NRR). Thus, if a hearing protector has such a label, 
    the mine operator can be confident that it meets MSHA's definition of a 
    hearing protector. As noted in the discussions of proposed 
    Sec. 62.120(a), MSHA does not believe the NRR ratings are meaningful in 
    workplace situations; moreover, other organizations have recommended 
    that the EPA reconsider the rating system it uses. MSHA is therefore 
    not proposing to delimit the range of hearing protectors that may be 
    offered to only those with an NRR as such; rather, any scientifically 
    accepted indicator of noise reduction value will be acceptable evidence 
    of the product's purpose.
        The Agency is interested in comments on this definition.
    Hertz (Hz)
        A unit of measurement of frequency, numerically equal to cycles per 
    second. The range of audible frequencies is 20 to 20,000 Hz.
    Medical Pathology
        A condition or disease affecting the ear. The term is used in the 
    proposed rule in contexts which do not require actual diagnosis and 
    treatment; see specifically the discussion of proposed Secs. 62.125 and 
    62.170. Medical conditions of this type should ultimately be diagnosed 
    and treated by a physician specialist, e.g., an otolaryngologist.
    Qualified Technician
        A technician who has been certified by the Council for 
    Accreditation in Occupational Hearing Conservation (CAOHC) or by 
    another recognized organization offering similar certification. MSHA 
    has decided that requiring a technician to be certified would ensure 
    that audiometric tests are administered by a competent person. The 
    definition of ``qualified technician'' is discussed in connection with 
    proposed Sec. 62.140 Audiometric testing program.
    Reportable Hearing Loss
        This defines the extent of hearing loss which must be reported to 
    MSHA so the Agency can intervene to prevent further hearing loss. Such 
    reporting is already required pursuant to 30 CFR part 50. This 
    definition clarifies how the requirements of 30 CFR part 50 apply in 
    the case of noise.
        The definition in the proposed rule would require that hearing loss 
    be calculated by subtracting the current hearing levels from those on 
    the baseline audiogram at 2000, 3000, and 4000 Hz; when the permanent 
    hearing losses at each frequency are averaged (added up and divided by 
    three), the hearing loss must be reported if the average loss in either 
    ear has increased by 25 dB. In making this calculation, a supplemental 
    baseline audiogram would be used in lieu of the baseline audiogram in 
    those cases in which the supplemental audiogram was created because of 
    a significant improvement in hearing acuity, in accordance with the 
    provisions of proposed Sec. 62.140(d)(2).
        The definition of reportable hearing loss is discussed in 
    connection with proposed Sec. 62.190, Notification of results; 
    reporting requirements. As discussed therein, the Agency is 
    specifically seeking comment on two points: (a) an appropriate 
    definition of reportable hearing loss in those cases in which operators 
    lack an audiometric test record; and (b) the nature of the hearing loss 
    that MSHA should capture through its part 50 reporting system.
    
    [[Page 66389]]
    
    Sound Level (in dBA)
        The sound pressure level measured in decibels using the A-weighting 
    network and exponential time averaging. Pursuant to proposed 
    Sec. 62.120(a)(3)(iv), sound pressure levels would be measured using 
    the A-weighting network and the slow-response time constant. Sound 
    consists of pressure changes in air caused by vibrations. These 
    pressure changes produce waves that move out from the vibrating source. 
    The sound level is a measure of the magnitude of these pressure changes 
    and is generally perceived as loudness.
    Standard Threshold Shift (STS)
        This defines the extent of hearing loss which requires intervention 
    by a mine operator pursuant to proposed Sec. 62.180.
        An STS is a measure of permanent change for the worse--relative to 
    a miner's baseline audiogram, or relative to the most recent 
    supplemental audiogram where one has been established pursuant to 
    proposed Sec. 62.140(d). The definition in the proposed rule would 
    require that hearing loss be calculated by subtracting the current 
    hearing levels from those measured by the baseline (or supplemental) 
    audiogram at 2000, 3000, and 4000 Hz; when the hearing losses at each 
    frequency are averaged (added up and divided by three), the hearing 
    loss would be considered an STS if the average loss in either ear has 
    reached 10 dB.
        MSHA discusses this definition in detail in connection with 
    proposed Sec. 62.160, Evaluation of audiogram.
        By contrast with an STS, a temporary threshold shift (TTS) is a 
    temporary change in hearing acuity, which corrects itself after sound 
    levels are decreased and does not permanently impair hearing. The 
    latter term is used frequently in the preamble, but is not needed in 
    the proposed rule.
    Supplemental Baseline Audiogram
        This is an annual audiogram used in certain specific cases in lieu 
    of the baseline audiogram to measure reportable hearing loss or 
    standard threshold shift. Some professionals prefer the term 
    ``revised'' baseline audiogram; in this proposal, ``supplemental'' is 
    used to ensure mine operators are clear that the integrity of the 
    original ``baseline'' audiogram must be preserved.
        A supplemental baseline audiogram is established under the 
    circumstances set forth in proposed Sec. 62.140(d)(1) or 62.140(d)(2). 
    See the discussion of those sections in this preamble, as well as the 
    related discussions of ``reportable hearing loss'' and ``standard 
    threshold shift.''
    Time-Weighted Average-8 Hour (TWA8).
        That sound level, which if constant over an 8-hour time period, 
    would result in the same noise dose as is measured. This yardstick 
    measurement is used in the rule in connection with various limitations; 
    for example, the proposed PEL would be a TWA8 of 90 dBA.
        Not all noise measurement instruments give readouts in terms of 
    time-weighted 8-hour averages. Many personal noise dosimeters, for 
    example, measure noise as a percentage of permitted dosage, with the 
    PEL equated to 100%. Mine operators therefore need to convert noise 
    dose to an equivalent TWA8 to determine if the action level or the 
    PEL has been exceeded, and to evaluate the impact of engineering 
    controls. Accordingly, MSHA has provided a list of TWA8 conversion 
    values in Table 62-2, included in proposed Sec. 62.120. The table has 
    been compiled by equating a dose of 100% to the proposed PEL. For 
    example, a dose of 50% equals a TWA8 of 85 dBA--the level at which 
    some protective action must be taken under the proposal.
        The TWA8 and the dose are to be used interchangeably. Since 
    the noise exposure will be measured for the entire shift, compliance 
    with the noise standard will be based upon the measured dose. If the 
    measured dose exceeds 100%, regardless of the length of the workshift, 
    the miner will be considered to be overexposed to noise. It would thus 
    be improper to adjust a TWA8 reading for an extended work shift.
        Care should be taken not to assume that those models of personal 
    noise dosimeters which give readouts in both the noise dose and the 
    ``average sound level'' in dBA are giving a TWA8 readout. The 
    ``Lavg'', or average sound level, is the constant sound level 
    which equals the dose over the measurement period. The value of the 
    TWA8 is the same as the Lavg if the measurement period is 8 
    hours.
        It should be noted that the TWA8 is a term used in the context 
    of a 5-dB exchange rate. In the context of a 3-dB exchange rate, the 
    equivalent term is the ``Leq,8''. The latter term is used 
    occasionally in the preamble--in discussing the possible use of a 3-dB 
    exchange rate, and in those studies performed with data from countries 
    using a 3-dB exchange rate.
    
    Section 62.120  Limitations on Noise Exposure
    
    Introduction
        The provisions of this section of the proposed regulation deal with 
    some critical subjects: how to compute a miner's noise dose; the 
    hierarchy of controls at different noise exposure doses; and the 
    monitoring of noise exposure.
        Specifically, paragraph (a) of proposed Sec. 62.120 provides the 
    parameters for computing the amount of noise to which a miner is 
    exposed--a miner's noise dose. Paragraphs (b) through (d) establish a 
    series of noise exposure limitations, and the specific mine operator 
    actions required if noise exceeds that level. Paragraph (e) establishes 
    a ceiling on sound levels to which a miner may be exposed. Paragraph 
    (f) establishes a mine operator's obligation to evaluate each miner's 
    noise exposure to determine if it exceeds any of the limitations 
    established by this section, and to notify miners at risk.
        A short summary of each subsection follows. Thereafter, a more 
    detailed presentation is provided.
    Sec. 62.120(a)
        Proposed paragraph (a) sets forth a formula for dose computation 
    which corresponds to the measurements made by most current personal 
    noise dosimeters. It further specifies that: all sound levels from 80 
    dBA to at least 130 dBA be integrated into the dose measurement, 
    including impact/impulse noise in that range; noise be measured over a 
    full shift; a 5-dB exchange rate be used; and that measurements be made 
    using the A-weighting network and slow response instrument settings. 
    This paragraph also clarifies that measurement of noise dosage is to be 
    made without regard for the effect of a hearing protector.
        The exchange rate is the measure that reflects how much of a 
    decrease in exposure time is required when the sound level increases. 
    The proposed 5-dB exchange rate is the same as under current standards. 
    Using that rate, the exposure permitted at a sound level of 90 dBA is 
    half that permitted at a sound level of 85 dBA--a miner gets the same 
    noise dose in 4 hours at 90 dBA as at 8 hours at 85 dBA.
        The Agency currently uses a 5-dB exchange rate. There appears to be 
    a consensus in the recent literature for an exchange rate of 3-dB. 
    Moreover, the current 5-dB exhange rates incorporates an assumption 
    that there is significant time for hearing to recover from high sound 
    levels. MSHA has concluded that
    
    [[Page 66390]]
    
    noise exposure under mining conditions does not warrant such an 
    assumption. A 3-dB exchange rate does not incorporate this assumption.
        Nevertheless, the Agency is proposing to retain the existing 5-dB 
    exchange rate because of feasibility considerations. Changing to a 3-dB 
    rate from a 5-dB rate would significantly reduce the amount of time 
    that miners could be exposed to higher sound levels without exceeding 
    the permissible exposure limit. For example, MSHA estimates that the 
    percentage of miners whose exposure would be in violation of a PEL set 
    at a Leq,8 of 90 dBA would be just about double that of a PEL set 
    at a TWA8 of 90 dBA. This means mine operators would have to 
    utilize controls to reduce exposures to the PEL more frequently--and 
    the controls required to reduce exposures that much would be more 
    expensive. Furthermore, it is extremely difficult to reduce the noise 
    exposures to below a Leq,8 of 90 dBA using currently available 
    engineering or administrative noise controls or a combination thereof. 
    Accordingly, moving the industry to a 3-dB exchange rate may be 
    infeasible at this time. (Part IV contains a further discussion of 
    feasibility issues.)
        Two features proposed with respect to noise measurement of 
    particular significance are: lowering the threshold at which sound 
    levels are integrated into a miner's noise dose, and prohibiting the 
    adjustment of noise measurements to provide credit for hearing 
    protector attenuation.
        MSHA is proposed that the threshold for integrating noise into dose 
    measurements be expanded to cover sounds as low as 80 dBA. This 
    decision is based on strong evidence that such exposures do contribute 
    to hearing impairment. While more protective than the present threshold 
    of 90 dBA, this change will generally result in higher dose readings in 
    both the coal and metal and nonmetal sectors than at present. For 
    example, MSHA's dual-threshold survey indicated that in the metal and 
    nonmetal industry, the percentage of samples above the PEL increased 
    from 17.4% at a 90 dBA threshold to 26.4% at an 80 dBA threshold; in 
    coal the figures increased from 25.3% to 35.6%.
        Moreover, the proposed regulation would not allow dose measurements 
    to be adjusted in those cases in which miners are wearing hearing 
    protectors. This is consistent with the thrust of the proposal to 
    establish for all mining sectors a hierarchy of controls for noise in 
    which primary reliance will be upon engineering and administrative 
    controls.
    Sec. 62.120(b)
        Proposed paragraph (b) establishes an ``action level'' at a 
    TWA8 of 85 dBA.
        The need for an action level reflects two facts: (1) There is a 
    significant risk of material impairment to miners from a lifetime of 
    exposure to noise at this level; and (2) the Agency believes it may not 
    be feasible at this time to lower the PEL to this level, since that 
    would require that mine operators use all feasible engineering and 
    administrative controls to reduce noise exposures to this level.
        The proposal would require that all miners exposed above the action 
    level be provided special instruction in the hazards of noise and 
    protective methods. The training is to be provided annually for as long 
    as exposure exceeds the action level. (The nature of this instruction, 
    how it is to be provided, and how it can be coordinated with other 
    required miner training are subjects discussed in connection with 
    proposed Sec. 62.130.)
        If a miner's exposure exceeds the action level but is below the 
    PEL, an operator will also be required to enroll a miner whose exposure 
    exceeds the action level in a hearing conservation program (HCP). While 
    enrollment in the HCP would require the operator to make annual 
    audiometric testing available to the miner, miners exposed to noise 
    below the PEL would have the right to decline taking any annual 
    audiometric testing. The requirements for such testing are discussed in 
    connection with proposed Sec. 62.140, audiometric test procedures. MSHA 
    is seeking comments on how to minimize the burden on mine operators of 
    providing audiometric examinations for those miners with only a 
    temporary attachment to the mining work force (e.g., summer employees), 
    while recognizing the importance of detecting and tracking hearing loss 
    among those who switch jobs.
        In addition, the operator must provide properly fitted hearing 
    protection--before the initial hearing examination, if a significant 
    threshold shift in hearing acuity is detected, and at any other time 
    upon miner request. Should it take more than 6 months to provide the 
    initial hearing examination because of the need to wait for a mobile 
    test van, or should a significant threshold shift in hearing acuity be 
    detected, the operator would also be required to ensure that the miner 
    wear the hearing protection--even if the miner's noise exposure remains 
    under the PEL. (A discussion of the timeframes for audiometric tests, 
    and the use of mobile test vans, is included in the discussion of 
    proposed Sec. 62.140, audiometric test program. The definition of a 
    significant threshold shift is discussed in connection with proposed 
    Sec. 62.160, evaluation of audiogram).
        An action level currently exists under OSHA but would be new to the 
    mining industry. As discussed herein, MSHA proposes to build upon the 
    requirements which have been used by OSHA while giving due regard to 
    implementation approaches appropriate to the circumstances of the 
    mining community.
    Sec. 62.120(c)
        Proposed paragraph (c) would establish the permissible exposure 
    limit (PEL) to noise for a miner as a TWA8 of 90 dBA during any 
    workshift. (This is also referred to as a dose measurement of 100%; the 
    action level TWA8 of 85 dBA is half this dose of noise.) The 
    proposal further provides that if the PEL is exceeded, in addition to 
    the controls required at the action level, the mine operator shall use 
    all feasible engineering and administrative controls to reduce the 
    miner's noise exposure to the PEL. The mine operator has a choice of 
    whether to use engineering controls, administrative controls, or both; 
    but if administrative controls are utilized, a copy of the procedures 
    involved must be posted, and copies given to the affected miners.
        If reducing the dose to this level with such controls is not 
    feasible, the proposal requires the mine operator to use such controls 
    to lower the noise exposure as much as is feasible.
        In addition, in such cases, the proposal requires that the operator 
    take extra steps to protect miner hearing. The operator must ensure all 
    miners so exposed take the annual hearing examinations, must provide 
    properly fitted hearing protection to all miners so exposed, and must 
    ensure the hearing protection is used by all miners so exposed.
        Under the proposal, a consistent hierarchy of controls is 
    established for all mines. Mine operators must first utilize all 
    feasible engineering and administrative controls to reduce sound levels 
    to the PEL before relying on other controls to protect against hearing 
    loss. This approach is consistent with that currently in place for 
    metal and nonmetal mines, but would be a change for coal mines. As 
    discussed herein (in connection with proposed Sec. 62.125, hearing 
    protectors), MSHA has considerable evidence that primary reliance upon 
    hearing protectors, as is the current case in the coal industry, is 
    misplaced.
        As under the present standards, the proposal would require a mine 
    operator
    
    [[Page 66391]]
    
    to use only such engineering controls as are technologically feasible, 
    and to use only such engineering and administrative controls as are 
    economically feasible for that mine operator.
        As noted, the proposed rule provides for supplemental controls in 
    those cases in which the Agency concurs with a mine operator that the 
    use of all feasible engineering and administrative controls cannot 
    reduce noise to the PEL. MSHA believes that when a miner is exposed to 
    such high levels of noise, these supplemental obligations are necessary 
    to protect miner hearing. Hearing protectors are not without their 
    discomforts; but the risk of hearing loss at such exposure levels ought 
    to be the controlling factor. While audiometric testing is not an 
    invasive procedure, the Agency is concerned that there may be economic 
    pressures and personal reasons that may lead miners to decline to take 
    hearing examinations. The information generated by these tests is 
    necessary, however, to trigger investigation of potentially serious 
    flaws in the layers of noise controls required at these high exposure 
    levels. In addition, the Agency believes that miners operating under 
    such high noise conditions should be aware of the severity of any 
    hearing loss; in a mining environment, this knowledge could have 
    implications for the safety of the miner and the safety of others. 
    Comments on this provision are specifically solicited.
    Sec. 62.120(d)
        Proposed paragraph (d) provides that should a miner's noise 
    exposure exceed a TWA8 of 105 dBA during any workshift, a dose of 
    800% of the PEL, the mine operator shall, in addition to taking all of 
    the actions required when exceeding the PEL, require the miner to use 
    dual hearing protection--i.e. both a plug type and a muff type hearing 
    protector. In this context, the Agency presents information about the 
    mining jobs at which the exposures of this level are occurring; and 
    requests comment on whether there should be an absolute dose ceiling, 
    regardless of the feasibility of control by an individual mine 
    operator.
    Sec. 62.120(e)
        Proposed paragraph (e) would provide that at no time shall a miner 
    be exposed to sound levels exceeding 115 dBA.
    Sec. 62.120(f)
        Proposed paragraph (f) consists of two parts. First, it would 
    require mine operators to establish a system of monitoring which 
    effectively evaluates each miner's noise exposure. This will ensure 
    that mine operators have the means to determine whether a miner's 
    exposure exceeds any of the limitations established by this section, as 
    well as to assess the effectiveness of noise controls. The proposed 
    rule is performance oriented in that the regularity and methodology 
    used to make this evaluation are not specified. Specific requirements 
    for periodic monitoring now applicable to the coal sector would be 
    revoked.
        Proposed paragraph (f) would also require that miners be notified 
    in writing should their exposure exceed any of the levels specified by 
    this section--whether based on operator or MSHA evaluations of noise. 
    Notice would be required within 15 calendar days.
        The proposal has been designed to ensure that miners are made aware 
    of the hazards they currently face. Miners exposed above the action 
    level should be notified of that fact so, for example, they can 
    consider the importance of using provided, properly fitted and 
    maintained hearing protectors. On the other hand, the proposal does not 
    require notification of a particular miner if an exposure measurement 
    indicates that the miner's exposure has not changed and the miner has 
    within the last year been apprised of the same information.
        The proposal has no provision for requiring the posting of warning 
    signs.
    Dose Computation
        Proposed Sec. 62.120(a) sets forth important technical 
    specifications on computing noise dose. These specifications were 
    utilized in the establishment of the limitations set forth in this 
    section; they therefore must be utilized in dose measurements taken to 
    determine compliance.
    Using a Personal Dosimeter
        The dose itself is usually read directly from a personal noise 
    dosimeter. The dosimeter is set to the specifications required by the 
    proposed standard (e.g. 80 dB threshold), attached to the miner, and 
    the total dose read out at the end of the full work shift.
    Using a Sound Level Meter
        Some operators may prefer to take a series of individual readings 
    with sound level meters, and derive the dose from these readings. 
    Accordingly, the proposal also sets forth the formula for determining 
    the dose in this fashion.
        Proposed Sec. 62.120(a)(1) would specify that noise dose is to be 
    computed by combining the sound levels during various periods of time 
    during the miner's measurement period, in accordance with the formula:
    
    D=100(C1/T1 + C2/T2+ * * * +Cn/Tn),
    
    where:
    
    D=the percent of permissible exposure,
    Cn=the total time of exposure at a specified sound level, and
    Tn=the reference duration of exposure at that level, as listed in 
    Table 62-1.
    
        Table 62-1 contains reference durations for sound levels from 85 to 
    115 dBA. The sound levels to be integrated into the dose measurement 
    pursuant to this proposal actually range from 80 to 130 dBA. Reference 
    durations for sound levels not in the table can be calculated pursuant 
    to the formula in the table note. (For a detailed discussion of this 
    topic see the section of this preamble entitled Threshold and range of 
    integration.)
        As noted, current personal noise dosimeters automatically compute a 
    miner's noise exposure essentially using the above formula. In fact, 
    noise dose is relatively simple to compute when the sound level is 
    constant throughout the work shift. For example, a miner is exposed to 
    95 dBA for 2 hours and has no additional noise exposure. The reference 
    duration, from Table 62-1, for 95 dBA is 4 hours. Substituting the 
    values into the above formula yields:
    
    D=100 (\2/4\) or equivalently 50%.
    
        When a miner is exposed to fluctuating sound levels, the total 
    noise dose can be computed using the same formula. For example, a miner 
    is exposed to 90 dBA for 1 hour, 95 dBA for 2 hours and 100 dBA for 1 
    hour. The reference durations from Table 62-1 are 8 hours, 4 hours, and 
    2 hours, respectively. Substituting the values into the above formula 
    yields:
    
    D=100 (\1/8\+\2/4\+\1/2\ ) or 100 (0.125+0.50+0.50) or equivalently 
    112.5%.
    Conversion of Dose to TWA8
        Table 62-2, included in proposed Sec. 62.120(a)(2), has been 
    constructed to permit dosage measurements to be converted readily into 
    time-weighted average 8-hour (TWA8) measurements.
        The TWA8 is the sound level which if constant over an 8-hour 
    time period, would result in the same noise dose as is measured. This 
    yardstick measurement is the one used to establish the action level, 
    PEL, and double-hearing protection supplemental control level in the 
    proposed regulation. Since personal noise dosimeters measure noise as a 
    percentage of permitted dosage, with the permissible exposure limit 
    (PEL) equated to 100%, this table allows for ready conversion of
    
    [[Page 66392]]
    
    those measurements into a form that measures compliance.
        As stated previously, the TWA8 and the dose are to be used 
    interchangeably. It is intended that the TWA8 not be adjusted for 
    extended work shifts. Since the noise exposure will be measured for the 
    entire shift, compliance with the noise standard will be based upon the 
    measured dose. If the measured dose exceeds 100%, regardless of the 
    length of the workshift, the miner will be considered to be overexposed 
    to noise. MSHA requests commenters to review the proposed rule and 
    offer suggestions to help the Agency ensure that this intention is 
    clearly conveyed in the rulemaking language.
        The table has been constructed by equating the proposed PEL to a 
    dose of 100%. More specifically, the TWA8 conversion values in 
    Table 62-2 are based on the use of a 90 dBA PEL, 80 dBA threshold, and 
    a 5-dB exchange rate. Interpolation for values not found in this table 
    can be determined from the following formula: TWA8=16.61 
    log10(D/100)+90, where D is the percent dose.
        It is important to understand that the exposure is interpreted as 
    if averaged over 8 hours. Thus, if a miner only works for 5 or 6 hours, 
    the sound levels can be higher during those hours than if the miner 
    works for 8 hours. Conversely, if a miner works an extended shift 
    (greater than eight hours), the sound levels would need to be lower. 
    Some current models of personal noise dosimeters will provide readings 
    in both dose and the average sound level (Lavg) over the sampling 
    period. Although the Lavg is useful in some circumstances, it is 
    only equal to the TWA8 when the period sampled is 8 hours.
    Consideration of Hearing Protector Attenuation
        Proposed Sec. 62.120(a)(3)(i) would require that when determining a 
    miner's noise dose, the attenuation of hearing protectors not be 
    considered. This provision would supplement the intent of proposed 
    Sec. 62.120(c) to preclude the current practice in the coal industry of 
    not issuing a citation based upon a noise exposure that exceeds the PEL 
    when the miners are wearing hearing protection.
        Several commenters recommended that no credit be given for hearing 
    protector attenuation in determining the miner's noise dose. These 
    commenters believed that engineering or administrative controls should 
    be given primacy over hearing protectors.
        Other commenters, however, supported an allowance for hearing 
    protector attenuation. Their recommendations varied from allowing the 
    full NRR value, to allowing only a 5 decibel attenuation for all makes 
    and models of hearing protectors.
        Field studies in mining by Giardino and Durkt (1996), Kogut and 
    Goff (1994), Giardino and Durkt (1994), Durkt (1993), Goff, et. al. 
    (1986), Durkt and Marraccini (1986), and Goff and Blank (1984) have 
    shown that the measured hearing protector attenuation at mines is far 
    less than the attenuation measured in the laboratory and is in some 
    cases minimal. Furthermore, the measured attenuations were highly 
    variable. These two factors make it virtually impossible to accurately 
    predict the in-mine effectiveness of hearing protectors in reducing 
    noise exposures. A more detailed discussion of hearing protector 
    performance and attenuation rating methods is presented in the Hearing 
    protector effectiveness section of this preamble.
        Table III-1 presents three types of information from various 
    jurisdictions. These items are--
        (1) the consideration of hearing protector attenuation when 
    determining the occupational noise exposure;
        (2) the weighting network used for measuring occupational noise 
    exposure; and
        (3) the instrument response time for measuring non-impulse/impact 
    occupational noise.
    
               Table III-1.--Features of Selected Legislation or Guidelines for Evaluating Non-Impulse/Impact Noise Tabulated for Various Entities          
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                         Credit for hearing protector                                                                                       
                  Entity                         attenuation                Weighting network                            Response times                     
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    U.S. Army........................  No.............................  A-weighting..............  Slow.                                                    
    U.S. Navy........................  Implied........................  A-weighting..............  Slow.                                                    
    U.S. Air Force...................  No.............................  A-weighting..............  Slow.                                                    
    Canada (consensus)...............  Not addressed..................  A-weighting..............  Slow (SLM only).                                         
    EEC..............................  No.............................  A-weighting..............  Slow or fast.                                            
    Australia (consensus)............  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM)                     
    Australia (national).............  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM).                    
    Western Australia................  No.............................  A-weighting..............  Fast (integrating SLM) or slow (SLM).                    
    South Africa.....................  Implied no.....................  A-weighting..............  Slow.                                                    
    ISO (consensus)..................  Implied no.....................  A-weighting..............  Fast (SLM).                                              
    ACGIH (consensus)................  Implied no.....................  A-weighting..............  Slow.                                                    
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    
        In reviewing the procedures for exposure measurement in regulations 
    and codes of practice (mandatory or recommended) from the selected 
    branches of the U.S. armed services, international communities, the 
    ISO, and the ACGIH, MSHA found that some diversity exists among the 
    methods used (See Table III-1). Nearly all of the entities either 
    specify or imply that attenuation provided by hearing protectors should 
    not be considered in determining a worker's noise exposure.
        Based on this information, MSHA has concluded that it would be 
    inappropriate to consider the attenuation of hearing protectors in 
    determining a miner's noise dose. As computed, the noise dose provides 
    a measurable foundation upon which can be built a noise control 
    program: including, as discussed herein, the use of hearing protectors 
    to attenuate that noise dose.
        This provision would supplement the intent of proposed 
    Sec. 62.120(c) to preclude MSHA's current practice in the coal industry 
    of not issuing a citation based upon a noise exposure that exceeds the 
    PEL when the miners are wearing hearing protection. This is consistent 
    with the thrust of the proposal to establish for all mining sectors a 
    hierarchy of controls for noise in which primary reliance will be upon 
    engineering and administrative controls. These issues are discussed at 
    length in connection with proposed Sec. 62.120(c) under Hierarchy of 
    controls and Hearing protector effectiveness.
    Threshold and Range of Integration
        Proposed Sec. 62.120(a)(3)(ii) would require that all sound levels 
    from 80 dBA to 130 dBA be integrated into the
    
    [[Page 66393]]
    
    miner's noise dose for determining compliance with the PEL. Sound 
    levels less than 80 dBA would not be included in the noise exposure 
    computation. By not excluding any particular types of sound from the 
    requirement, MSHA intends that the term ``all sound levels'' include, 
    but is not limited to, continuous, intermittent, fluctuating, impulse, 
    and impact noise.
        MSHA currently uses a threshold of 90 dBA for all purposes. OSHA, 
    however, uses a dual threshold: a 90 dBA threshold for measuring 
    whether a dose exceeds its PEL (TWA8 of 90 dBA), and an 80 dBA 
    threshold for determining whether a dose exceeds its action level 
    (TWA8 of 85 dBA).
        Many of the commenters to MSHA's ANPRM supported a threshold of 80 
    dBA. Some specifically supported a single threshold. One of these 
    commenters stated the following:
    
        It was an undue burden on employers when OSHA adopted a dual 
    threshold level (90 dBA when sampling for PEL and 80 dBA when 
    sampling for a Hearing Conservation Program). Few employers in our 
    practice understand the difference, and in fact, very few service 
    providers in our area understand the dramatic differences these two 
    threshold levels can create. MSHA has the opportunity to correct 
    this [oversight] by OSHA, and would be wise to adopt the 80-dBA 
    threshold.
    
        Another commenter stated:
    
        MSHA should use an 80-dBA threshold for integrating noise on 
    dosimeters for both compliance with the PEL and the action level. 
    The exposure characterization of levels between 80 dBA and 130 dBA 
    would be more accurate using an 80-dBA threshold dosimeter versus a 
    90-dBA integrating dosimeter.
    
        A third commenter recommended the following:
    
        One threshold level should be used for all measurements--80 dBA. 
    A single threshold level of 80 dBA, as compared to separate 
    thresholds of say, 90 dBA and 80 dBA, would greatly simplify and 
    reduce the costs of measuring noise exposure levels and would 
    provide an additional margin of safety.
    
        Several commenters recommended that the current threshold of 90 dBA 
    be retained. One of these commenters stated the following:
    
        * * * multiple thresholds would be extremely burdensome and 
    costly and would require companies to purchase and use meters that 
    integrate at different levels. * * * the requirement that more than 
    one threshold be used is unsupported by reliable and widely accepted 
    scientific data and is unnecessary for protection of the health of 
    miners.
    
        Two commenters supported the use of a dual threshold consistent 
    with OSHA's current standard, while another commenter recommended a 
    threshold of 75 dBA, because EPA had said that 75 dBA equates to no 
    risk.
        One mining association commented that a member company had 
    collected about 4,500 samples between 1985 and 1988 using personal 
    noise dosimeters set at an 80 dBA threshold and found that about 20% of 
    the measurements equalled or exceeded the PEL. MSHA notes these results 
    are comparable to the results of the dual-threshold survey conducted by 
    the Agency and reviewed in part II.
        According to ACGIH (1994) all sound levels exceeding 80 dBA should 
    be integrated into the daily noise exposure. Because permissible 
    durations are presented for sound levels up to 139 dBA, the range of 
    integration can be inferred to be 80 to 139 dBA.
        ANSI S1.25-1991, ``Specification for Personal Noise Dosimeters'', 
    recommends that the threshold level be set at least 5 dB below the 
    criterion level. Although ANSI S1.25-1991 specifies personal noise 
    dosimeters to have an operating range of at least 50 dB, most currently 
    manufactured personal noise dosimeters have an operating range greater 
    than 50 dB. In addition, these personal noise dosimeters will integrate 
    sound levels up to 140 dBA to include impulse/impact noise at pre-
    selected thresholds of 80 dBA, 85 dBA, and 90 dBA.
        There is general agreement among the EEC, the ISO, the 
    international community, and selected branches of the U.S. armed 
    services that all types of noise be integrated in the worker's noise 
    dose; however, a threshold is not always specified.
        Moreover, based on its review of the available evidence, MSHA has 
    determined that the use of a single 80 dBA threshold for determining a 
    miner's noise exposure is necessary for miner protection. Its many 
    advantages include:
        (1) it would address the risk of hearing impairment from prolonged 
    exposure (greater than 8 hours) above 80 dBA;
        (2) it would improve the accuracy of exposure measurements, 
    ensuring that at-risk miners would be accurately identified;
        (3) it is consistent with OSHA's 80 dBA threshold for HCP 
    requirements, allowing for comparison data;
        (4) it would be less burdensome than using dual thresholds, 
    allowing the use of a single, less complex personal noise dosimeter to 
    collect the required information rather than a more expensive 
    instrument or two separate instruments; and
        (5) a single threshold is appropriate in as much as MSHA's proposed 
    approach to hearing conservation is linked closely to other parts of 
    its proposal.
        Several consequences should be noted of switching to a threshold of 
    80 dBA from the present threshold of 90 dBA. As noted in part II of 
    this preamble, MSHA inspectors conducted comparative sampling for 
    several years, simultaneously collecting readings at both the 90 dBA 
    and 80 dBA thresholds. Tables II-11 and II-12, located in part II of 
    the Preamble, show the effect of using an 80 dBA threshold versus a 90 
    dBA threshold with a criterion level of 90 dBA. Of the more than 42,000 
    samples collected in metal/non-metal mines, for example, 7,360 (17.4%) 
    exceeded a criterion of 90 dBA using a 90 dBA threshold; whereas, 
    11,150 (26.4%) exceeded the 90 dBA criterion using an 80 dBA threshold. 
    Hence, the use of an 80 dBA threshold will result in a higher 
    proportion of samples exceeding the PEL. Also, an 80 dBA threshold 
    means that in the case of an extended workshift of more than 8 hours, 
    sound levels that average below 90 dBA can result in a dose that 
    exceeds the PEL. For example, the PEL for a 16-hour workshift is 85 
    dBA, which equates to a TWA8 of 90 dBA.
        Further, based upon research conducted by MSHA, the Agency has 
    determined that the effect of switching to a lower threshold is not 
    linear. Sound levels just under 90 dBA will have a much greater impact 
    on the dose computation than those nearer 80 dBA.
    Full-Shift Sample
        Proposed Sec. 62.120(a)(3)(ii) would also require that compliance 
    with the PEL or action level be based on the determination of a miner's 
    full-shift noise exposure. Typically, a full-shift measurement would be 
    taken with a personal noise dosimeter. This procedure would be 
    consistent with MSHA's existing noise standards and sampling 
    procedures.
        OSHA's noise standard does not specify a sampling duration, other 
    than to require personal monitoring where circumstances such as high 
    worker mobility, significant variation in sound level, or a significant 
    component of impulse noise make area monitoring generally 
    inappropriate. OSHA does require that the sample be representative of 
    the worker's exposure.
        In response to MSHA's ANPRM, numerous commenters addressed sampling 
    duration, including the question of novel work shifts (work shifts 
    differing from 8 hours). Many commenters stated that the noise 
    measurement should encompass the entire work shift regardless of 
    duration. For those shifts which exceed 8 hours,
    
    [[Page 66394]]
    
    a number of commenters suggested that the PEL be adjusted to account 
    for the longer work shift. Others suggested that the noise exposure be 
    adjusted.
        Several commenters advocated the use of a 40-hour noise exposure 
    instead of a daily 8-hour noise exposure because of the widely varying 
    noise exposure of miners. These commenters believed that the 40-hour 
    exposure would present a better representation of the noise exposure.
        A few commenters addressed partial shift sampling. At many small 
    mines, miners may be involved with several different jobs with 
    different noise exposures. Because of this, one commenter believed that 
    partial-shift sampling was more representative of a miner's noise 
    exposure. The commenter did not want the highest partial-shift noise 
    exposure projected to a full-shift and reported as the typical exposure 
    for that shift. Another commenter suggested that the survey duration 
    encompass at least two-thirds of the shift in order to represent a 
    full-shift sample.
        Lancaster (1986), in a study of noise exposure of British coal 
    miners, reported that the variation in the day-to-day occupational 
    noise exposure of compressed air drillers and electricians had a range 
    that exceeded 30 dBA. The smallest range for any of the fifteen 
    occupations was 8 dBA. Lancaster reported that five-shift samples 
    greatly reduced the chance of getting an unrepresentative high or low 
    result. Further, Lancaster concluded that a five-shift sample was not a 
    reliable routine method for determining the long-term noise exposure. 
    In order to determine the long-term average noise exposure to within an 
    accuracy of 2 dBA, Lancaster stated that 4 to 57 samples are needed 
    depending upon the occupation.
        MSHA concurs with the majority of commenters that full-shift 
    sampling is more representative of the noise exposure than partial-
    shift sampling. Therefore, MSHA has determined that a full-shift 
    measurement is necessary because partial-shift noise surveys do not 
    account for such factors as: variable work tasks, worker mobility, and 
    no set production pattern for many mining situations. These occurrences 
    are commonplace in the mining industry.
        The Agency did not include a long-term sampling requirement in the 
    proposal. Such a requirement would be burdensome to the mining industry 
    and is not relevant to compliance with the proposed standard, which 
    will be based upon a single full-shift sample by the Agency. (For 
    further consideration of MSHA compliance policy in this regard, see the 
    last of the Questions and Answers in part I.)
    Impulse/Impact Noise
        MSHA's proposal does not include a specific limit on impulse or 
    impact noise. Rather, it provides that all noise in the range from 80 
    dBA to 130 dBA be integrated into a miner's noise dose, including any 
    impulse/impact noises measured in those ranges. Most personal noise 
    dosimeters cover this range of sound levels. MSHA has concluded that, 
    currently, there is not a sufficient scientific consensus to support a 
    separate impulse/impact noise standard. Further, existing procedures, 
    for identifying and measuring such sound, lack the practicality to 
    enable its effective enforcement: for example, many personal noise 
    dosimeters do not permit use of the fast response settings needed to 
    isolate sounds of this type. Since industrial impulses are almost 
    always superimposed on a background of moderate-to-high levels of 
    continuous noise, and since both may be harmful, MSHA has determined 
    that it is only reasonable to consider their effect together, rather 
    than to treat each separately. As indicated below, there is ample 
    justification for this approach in the studies reviewed by MSHA and 
    comments submitted to the record.
        MSHA's existing noise standards for coal mines do not include a 
    limit for impulse/impact noise. Both OSHA's and MSHA's Metal and 
    Nonmetal existing noise standards limit impulse/impact noise to a peak 
    level of 140 dB. Neither standard, however, specifically defines 
    impulse/impact noise nor procedures to measure it.
        OSHA, in its Hearing Conservation Amendment, determined that 
    impulse noise should be combined with continuous noise to calculate 
    employee noise exposure for purposes of the HCP. OSHA's standard, 
    however, retains the 140 dB peak limit on impulse and impact noise. The 
    OSHA preamble to its Hearing Conservation Amendment (46 FR 4099) 
    stated:
    
        Since industrial impulses are almost always superimposed on a 
    background of moderate to high levels of continuous noise * * * and 
    since both may be harmful, it is only reasonable to consider their 
    effects together rather than to treat each separately * * *. The 
    decision to measure all noise exposures for purposes of the hearing 
    conservation program is a pragmatic approach to the whole problem of 
    impulse noise. For, while there is some dispute as to the precise 
    definition and effect of impulse noise, there is general agreement 
    that impulse noise is damaging.
    
        Impulse/impact noise is typically characterized by a rapid rise 
    time, high peak value of short duration, and rapid decay.
        In 1974, OSHA proposed the following definition for impulse noise 
    (39 FR 37775):
    
    * * * a sound with a rise time of not more than 35 milliseconds to 
    peak intensity and a duration of not more than 500 milliseconds to 
    the time when the level is 20 dB below the peak. If the impulses 
    recur at intervals of less than one-half second, they shall be 
    considered as continuous sound.
    
        At that time, OSHA proposed to limit exposure to impulses at 140 dB 
    to 100 per day, and to permit a tenfold increase in the number of 
    impulses for each 10-dB decrease in the peak pressure of the impulse. 
    OSHA stated that this proposal was in accordance with the criterion 
    proposed by McRobert and Ward (1973). OSHA's proposal on impulse noise 
    exposure limits was identical to that recommended by the ACGIH (1986).
        Currently, there is no uniformly accepted definition of impulse or 
    impact noise. ANSI S12.7-1986, ``Methods for Measurement of Impulse 
    Noise'', defines impulse noise as ``a single short burst or a series of 
    short bursts of sound pressure. The pressure-time history of a single 
    burst includes a rise to a peak pressure, followed by a decay of the 
    pressure envelope.''
        The ACGIH (1986) states that:
    
        Impulsive or impact noise is considered to be those variations 
    in noise levels [sound levels] that involve maxima at [time] 
    intervals of greater than one per second. Where the intervals are 
    less than one second, it should be considered continuous.
    
        Integrating impulse/impact noise into the miner's noise dose is 
    broadly supported by many of the commenters. One commenter stated that 
    currently there is not enough scientific information to promulgate a 
    separate standard on impulse/impact noise. Several commenters advocated 
    retaining the current MSHA Metal and Nonmetal 140 dB peak limit. 
    However, two commenters indicated that exposure to this peak be limited 
    to 100 occurrences per work shift. One commenter on this issue 
    recommended that MSHA adopt the measurement methods described in ANSI 
    S12.7-1986, ``Methods for Measurement of Impulse Noise''. This ANSI 
    document, however, does not specify a criterion level for such noise. 
    Another commenter stated that 156 dB is most likely the critical point 
    at which the sensory components of the human ear disintegrate.
        Defining impulse/impact noise, and setting an appropriate limit, 
    has proven to be an arduous task mainly because of the difficulty in 
    measuring such sound and differentiating it from non-impulse/impact 
    noise that may occur simultaneously. Impulse/impact noise
    
    [[Page 66395]]
    
    seldom occurs alone in the mining environment. Several commenters on 
    this issue indicated that current instrumentation, including in 
    particular the personal noise dosimeter, cannot distinguish between 
    impulse/impact and continuous noise occurring simultaneously. Some 
    commenters stated that although personal noise dosimeters cannot 
    distinguish between impulse/impact noise and continuous noise, newer 
    models of personal noise dosimeters are capable of accurately 
    integrating the two types of noise into a single combined dose.
        The studies reviewed by MSHA and discussed below indicate that even 
    though there is no consensus as to a definition of impulse/impact 
    noise, all researchers and regulators agree that this type of noise is 
    damaging to hearing.
        Ward (1990) stated that both impulse and impact noises involve high 
    sound pressure levels and short durations, so in a sense, they jointly 
    represent an extreme type of intermittent noise. He believed, however, 
    that there is considerable evidence that a distinction should be made 
    between impulse noise and impact noise, and that they should be treated 
    separately. Ward characterized impulse noise as ``A-duration,'' such as 
    that from gunfire. Whereas he characterized impact noise as ``B-
    duration,'' having multiple, nearly equal peaks and a sustained 
    reverberation that may endure for a second or even longer.
        Ward believed that recent research tends to support the conclusion 
    that impact noise can reasonably be expected to behave in a manner 
    similar to that of intermittent exposure to short bursts of otherwise 
    continuous but high-intensity noise. He stated that any predictive 
    scheme that accurately estimates the hazard of intermittent noise in 
    the range of time-weighted averages (TWA8) or Leq,8 of 110 
    dBA to 130 dBA also would be successful in predicting the hazard from 
    impact noise, and no ``correction for impulsiveness'' should be 
    necessary. He further stated, the same is true of impulse noise as long 
    as the level of the pulse does not exceed some ``critical'' value. If 
    the impulse exceeds this critical level, however, Ward believed that 
    the hazard increases rapidly with further increases in level or in the 
    number of impulses.
        Ward stated that the most hazardous impulse would be one that has 
    its maximum energy in the most sensitive region of the human auditory 
    system: namely 2000 to 3000 Hz. This occurs when the A-duration is 
    around 0.2 milliseconds (ms). For pulses whose A-duration is in this 
    vicinity, he believed the critical level to be around 150 dB for the 
    average individual and around 140 dB for the most susceptible ears. He 
    believes, however, that his limit results in overprotection against 
    pulses whose A-duration is short (as in the case of cap guns) or long 
    (as with cannons or sonic booms).
        Ward concluded that impulse noise may be the most important cause 
    of NIHL in the general population, not by a gradual erosion of auditory 
    sensitivity through repeated daily exposure, but rather by a single 
    event causing acoustic trauma. He emphasized, however, that the 
    determination of valid exposure limits for specific impulses is still a 
    major problem.
        In the American Industrial Hygiene Association (AIHA) Noise & 
    Hearing Conservation Manual, Ward (1986) also expressed concern 
    regarding an impulse/impact noise limit. He stated:
    
        Just where, if anywhere, this type of limit should be placed is 
    still undecided. Although the present OSHA regulations state: 
    ``Exposure to impulsive or impact noise should not exceed 140 dB 
    peak sound pressure'' (Anon., 1971), this number was little more 
    than a guess when it was first proposed in the CHABA document 
    (Kryter et. al., 1966), and no convincing supportive evidence has 
    since appeared. While 140 dB may be a realistic ceiling for impact 
    noises, it is inappropriate for impulses, so exposure limits in 
    which the permitted peak level increases as the duration of the 
    pulses becomes shorter should continue to be used (Anon., 1968).
    
        Volume II of the Ohio State University Research Foundation report 
    (Melnick et al., 1980) discussed the effects of single, high-level 
    impulses and stated:
    
        There are insufficient data to develop distributions of hearing 
    loss as the function of the parameters of single, high-intensity 
    impulses. The very nature of the stimulus makes these effects on man 
    difficult to quantify.
    
        This report, however, stated the following regarding single impulse 
    levels that could cause damage:
    
    * * * In experiments with laboratory animals, impulses having peak 
    levels in the range of 150 to 160 dB were capable not only of 
    producing damage to the inner ear but also showed evidence of trauma 
    to the structures of the middle ear, including perforation of the 
    tympanic membrane (Eames et al., 1973). Pfander (1975) reports that, 
    in humans, perforations of the tympanic membrane were observed when 
    the peak level for an explosive impulse was in the range of 180 dB. 
    In his experiments with the effects of sonic booms on mice using 
    peak levels that range from 126 to 146 dB, with durations in excess 
    of 100 msec, Reinis (1976) reported that five such booms delivered 
    at the rate of 1 every 10 seconds are capable of producing bleeding 
    in the cochlea of the experimental animals.
    
        The Committee on Hygiene Standards of the British Occupational 
    Hygiene Society (1976) developed standards for impulse noise. Their 
    recommendation referenced a study by Kryter and Garinther which 
    ``showed that temporary hearing loss after exposure to 100 impulses 
    increased rapidly at sound pressure levels exceeding 170 dB.'' Kryter 
    and Garinther, however, recommended limiting instantaneous sound 
    pressure levels to 150 dBA, because special measurement techniques and 
    instruments would be needed to measure levels in excess of 150 dBA.
        Shaw (1985) recommended, in the interest of simplicity and in 
    keeping with ISO/DIS 1999-1984, that the use of hearing protectors be 
    mandatory where there is exposure to noise at the work place with 
    instantaneous peak sound pressures exceeding 200 pascals (140 dB 
    relative to 20 micropascal). Shaw stated, however, that exposure to 
    many simple non-reverberant impulses (``clicks'') at that level would 
    be required to produce significant temporary threshold shift even in 
    the most sensitive ears. Shaw further discussed the concept of 
    ``critical level'' and stresses that ``the relationship between peak 
    sound pressure level and mechanical or physiological stress * * * is 
    exceedingly complex.'' Shaw quoted McRobert and Ward (1973) who urged 
    that ``* * * damage risk criteria incorporate a more complicated 
    criterion for impulse and impact noise than a simple ceiling or peak 
    level * * *.''
        ISO/DIS 1999-1990 (1990) also supported combining continuous noise 
    with impulse/impact noise in conjunction with the use of a 3-dB 
    exchange rate.
        In discussing the combined effects of continuous and impulse/impact 
    noise, the ACGIH (1986) stated that:
    
        Some studies have shown that the effects of combined impulse and 
    continuous noise are additive [Okada et al., Int. z Angew. Physiol., 
    30:105-111 (1972)]. Other studies have shown that rapidly repeated 
    impulses [Coles and Rice, Occupational Hearing Loss, pp. 71-77 
    (1971)] and simultaneously continuous noise [Cohen et al., J. 
    Acoust. Soc. Am., 40:1371-1379 (1966)] in some cases provide up to 
    10 dB of protection.
    
        Evans and Ming (1982) and Sulkowski and Lipowczan (1982), however, 
    supported the theory that impulse noise superimposed on steady-state 
    noise is more hazardous than the same levels of either separately. 
    Cluff (1982), professor of audiology at Arizona State University, 
    believed that the combined
    
    [[Page 66396]]
    
    continuous/impulse noise dose procedure should be approached with a 
    degree of caution. He stated that:
    
        The procedure involves some knotty issues; not the least of 
    which is the issue of equal energy (3-dB doubling rule) vs 
    equinocivity (the principle embodied in the 5-dB doubling rule). One 
    other issue deserves mention also. What is impact/impulse noise? It 
    is a simple matter to describe impact/impulse noise in terms of its 
    source when the source is obvious and individual events are spaced 
    far apart temporally. It is quite another matter to describe it 
    differentially from continuous noise when the source is not obvious 
    and when individual events are repeated rapidly (as with the case of 
    gear trains, pneumatic chisels, conveyor belts, grinders, internal 
    combustion engines, etc.). Indeed, this difficulty may be central to 
    the heretofore tendency to class it as continuous noise when the 
    repetition rate exceeds one or two events per second. Were it not 
    that the weight of evidence appears to argue against this approach, 
    the simple thing would be to call it continuous noise and treat it 
    as such.
    
        As shown in Tables III-4 and III-5 (in the section entitled 
    Permissible exposure level (PEL), discussing proposed Sec. 62.120(c)), 
    the majority of international communities and selected branches of the 
    U.S. armed services have adopted 140 dB peak as the upper limit for 
    sound levels in their respective regulations. However, there is no 
    consensus among these regulators as to a definition of impulse/impact 
    noise.
        In reviewing the literature on impulse/impact noise, MSHA found 
    that such noise frequently is divided into two general categories: ``A-
    duration'' impulses are short duration (measured in microseconds) and 
    non-reverberant in that they usually occur outside or in a sound 
    deadening environment; and ``B-duration'' impacts are of longer 
    duration (measured in milliseconds) and are reverberant mainly because 
    they occur inside where the sound is augmented by reflections from hard 
    surfaces. MSHA's experience indicates that there is seldom impulse 
    noise of A-duration in mills and underground mines, because of the 
    reverberant field. Scheduled blasting at surface mines would not be 
    impulse noise of A-duration because of the multiple detonations several 
    milliseconds apart in a semi-reverberant field when considering the 
    rock walls and floor.
        MSHA is concerned about the practicality of enforcing an impulse/
    impact noise limit in mining. Distinguishing impact/impulse noise from 
    continuous noise, according to most of the definitions discussed above, 
    would require sophisticated, delicate laboratory instrumentation. This 
    equipment is: cumbersome, not intrinsically safe, not readily 
    available, and not capable of withstanding the harsh mining 
    environment.
        As pointed out by some commenters, there have been many 
    technological advances in the capabilities of noise measuring 
    instruments, and equipment now exists that can integrate impulse/impact 
    noise into the dose. The ability of personal noise dosimeters to 
    accurately integrate sound levels above 130 dBA into the noise dose, 
    however, may be questionable. ANSI S1.25-1991, ``Specification for 
    Personal Noise Dosimeters'', specifies that personal noise dosimeters 
    must have an operating range of 50 dB. ``Operating range'' is defined 
    by ANSI as the range between threshold and an upper sound level within 
    which a personal noise dosimeter operates within stated tolerances. 
    Accordingly, if an 80 dBA threshold is used, current personal noise 
    dosimeters would be required to meet ANSI tolerances up to 130 dBA.
        As stated previously, MSHA has determined that there is little 
    noise in mining that could be characterized as impact or impulse given 
    their prevailing definitions. One source of impact noise that may 
    exceed the existing 140 dB criteria is that caused by blasting in 
    underground mines. MSHA has determined that noise from blasting in 
    underground mines would be considered impact noise rather than impulse 
    noise because of the highly reverberant environment.
        In Volume II of the Ohio State University Research Foundation 
    report (Melnick et al., 1980), Melnick et al. states the following with 
    regard to measuring impulse/impact noise, such as that produced by 
    blasting:
    
        Under conditions sufficient to produce measurable hearing loss, 
    it would be extremely fortuitous if measuring instruments were in 
    place to permit the assessment of the actual exposure of the single 
    impulsive event. Generally, these exposures are accidental in 
    nature.
    
        Because blasting occurs at irregular intervals, with most miners 
    removed from the blast site prior to its initiation, it would be 
    difficult for MSHA to measure such exposures and to enforce a limit 
    designed to protect against such exposures.
        MSHA considered many factors in determining the merit of proposing 
    an impulse/impact noise limit for the mining industry. Although there 
    is much evidence in the literature on the harmful effects of impulse/
    impact noise, MSHA concluded that, currently, there is not a sufficient 
    scientific consensus to support a separate impulse/impact noise 
    standard. Further, existing procedures for identifying and measuring 
    such sound lack the practicality to enable its effective enforcement. 
    This is due, in part, to the complexity of the phenomena, where 
    consideration must be given to such factors as: the peak sound pressure 
    level; the wave form and crest factor; the rise and decay time; whether 
    it is A-duration or B-duration; the number of impulses per day; the 
    presence or absence of steady-state sound; the frequency spectrum of 
    the sound; and the protective effect of the middle ear acoustic reflex.
        In conclusion, studies discussed above indicate that when impulse/
    impact noise is combined with continuous noise, hearing loss is 
    exacerbated. Therefore, MSHA has determined that, for purposes of this 
    proposal, impulse/impact noise should be combined with continuous noise 
    for purposes of calculating a miner's noise exposure. Since industrial 
    impulses are almost always superimposed on a background of moderate-to-
    high levels of continuous noise, and since both may be harmful, it is 
    only reasonable to consider their effect together, rather than to treat 
    each separately. There is ample justification for this approach in the 
    studies reviewed by MSHA and comments submitted to the record.
        MSHA, however, requests further comment on this issue, particularly 
    on impulse/impact noise sources in mining which may not be integrated 
    adequately into the miner's noise dose. Additionally, MSHA requests 
    data addressing a critical level to prevent traumatic hearing loss; 
    what this critical level should be; whether it should be based on a 
    single event; and a practical scientifically validated method for its 
    discrete measurement.
    Exchange Rate
        The exchange rate is another factor which is involved in the 
    determination of noise dose. The exchange rate is the change in sound 
    level which corresponds to a doubling or a halving of the exposure 
    duration. For example, using a 5-dB exchange rate, a miner who receives 
    the maximum permitted noise dose over an 8-hour exposure to 90 dBA 
    would be determined to have accumulated the same dose as a result of 
    only a 4-hour exposure at 95 dBA. If the exchange rate were reduced to 
    3-dB, the same dose would be received with a 4-hour exposure at only 93 
    dBA. Other terms for exchange rate include ``doubling rate,'' ``trading 
    ratio,'' and ``time-intensity tradeoff.''
        The Agency currently uses a 5-dB exchange rate. There appears to be 
    a concensus in the recent literature for an exchange rate of 3-dB, 
    although the Agency is seeking additional
    
    [[Page 66397]]
    
    information on this point. Moreover, the current 5-dB exchange rates 
    incorporates an assumption that there is significant time for hearing 
    to recover from high sound levels. MSHA has concluded that noise 
    exposure under mining conditions does not warrant such an assumption. A 
    3-dB exchange rate does not incorporate this assumption.
        Nevertheless, the Agency is proposing to retain the existing 5-dB 
    exchange rate because of feasibility considerations. Changing to a 3-dB 
    rate from a 5-dB rate would significantly reduce the amount of time 
    that miners could be exposed to higher sound levels without exceeding 
    the permissible exposure limit. For example, MSHA estimates that the 
    percentage of miners whose exposure would be in violation of a PEL set 
    at a Leq,8 of 90 dBA would be just about double that of a PEL set 
    at a TWA8 of 90 dBA. This means mine operators would have to 
    utilize controls to reduce exposures to the PEL more frequently--and 
    the controls required to reduce exposures that much would be more 
    expensive. Furthermore, it is extremely difficult to reduce the noise 
    exposures to below a Leq,8 of 90 dBA using currently available 
    engineering or administrative noise controls or a combination thereof. 
    Accordingly, moving the industry to a 3-dB exchange rate may be 
    infeasible at this time. (Part IV contains a further discussion of 
    feasibility issues.)
        OSHA, in its 1974 proposed noise standard (39 FR 37774), stated the 
    following regarding its decision to use a 5-dB exchange rate:
    
        EPA recommended [in response to OSHA's proposal] a doubling rate 
    [exchange rate] of 3 dB. While the 3-dB doubling rate is 
    hypothetically correct for uninterrupted noise exposure, noise 
    exposure in industry is normally interrupted since there are several 
    breaks in the day's work. OSHA agrees with the Advisory Committee 
    [Standards Advisory Committee on Noise, appointed by the Assistant 
    Secretary for OSHA] that the doubling rate should be adjusted to 
    take into account the various breaks which occur in a workday. 
    Therefore, OSHA believes that a doubling rate of 5 dB is more 
    appropriate than the 3 dB.
    
        MSHA received numerous comments regarding this particular issue. 
    Many refer to scientific studies showing the ability of the ear to 
    recover from temporary shifts (temporary threshold shifts, or TTS) 
    incurred during noise exposure. TTS should not be confused with PTS, 
    which refers to permanent theshold shifts--i.e., loss of hearing 
    acuity. Whether TTS and PTS are inexorably linked is a subject of 
    debate, as noted below.
        Many commenters advocated retaining the existing 5-dB exchange 
    rate. Two of these commenters believed that there is sufficient support 
    in the scientific literature for a 3-dB exchange rate, but recommended 
    that MSHA retain using the 5-dB exchange rate so as to maintain 
    consistency between MSHA and OSHA.
        A number of commenters, however, recommended a 3-dB exchange rate. 
    Several stated that it has greater scientific and technical validity. 
    Others supported the 3-dB exchange rate because it would be in 
    agreement with regulations in many countries outside the United States 
    and with the recently issued international standards [International 
    Standards Organization, ISO 1999.2] which the U.S. endorsed. One 
    commenter asserted that the ``use of the 3-dB, rather than a 5-dB, 
    exchange rate facilitates the calibration/characterization and the 
    interpretation of the performance of such [noise measuring] 
    instruments.'' Another commenter criticized the theory that the 3-dB 
    exchange rate only applies to steady state noise, stating the 
    following:
    
        First, steady and intermittent noise merely identifies the 
    extremes of episodes of noise and quiet that most workers experience 
    in the course of a day. It is the rare exception to find workers who 
    experience either continuous or steady state noise. Recovery from 
    noise-induced damage, therefore, is unpredictable in the real world. 
    Second, the hypothesis of recovery during intermittent noise 
    exposure has not been empirically verified.
    
        Other commenters stated that the use of the 3-dB exchange rate is 
    not appropriate in mining because exposures in the mining industry are 
    intermittent and, therefore, miner recovery from temporary threshold 
    shifts occurs during the working day. Finally, two commenters stated 
    that if the exchange rate were lowered, many of the personal noise 
    dosimeters currently in use would become obsolete and would have to be 
    replaced.
        MSHA reviewed several recent studies relating to the selection of 
    an exchange rate. Kryter (1984) in his discussion of interruptions in 
    and durations of daily noise exposures, asserts that even short periods 
    of reduced noise exposure during the workday facilitate recovery, and 
    that a 5-dB exchange rate is thus appropriate to take this into 
    account. He states:
    
    * * * it does not matter whether the off time is continuous or 
    interrupted during the 8-hour day. In either case, the recovery 
    process continues and is equally effective. For example, the level 
    of a noise of 8 hours duration per workday could be increased by 6 
    dB and cause no additional PTS provided its duration is decreased to 
    4 hours, either by reducing the total work period by 4 hours or by 
    introducing ``off'' periods (longer than 10 sec each) which total 4 
    hours. This, of course, is in reasonably close agreement with the 
    ``5 dB exchange'' that would be allowed in some noise assessment 
    procedures, such as the U.S. Department of Labor Occupational Safety 
    and Health Administration (OSHA) regulations.
    
        Dear (1987) supported retaining the 5-dB exchange rate based upon 
    the studies of Sulkowski (1980), Gosztonyi (1975), Scheiblechner 
    (1974), Schneider (1970) and Pell (1973). Further, Dear believed that 
    the studies of Passchier-Vermeer (1973) and Burns and Robinson (1970), 
    which formed the basis for Shaw's recommendation to adopt a 3-dB 
    exchange rate (discussed below), were critically flawed and furthermore 
    the findings of Passchier-Vermeer did not agree with those of Burns and 
    Robinson. Dear asserted that Shaw discounted other studies which showed 
    that the 5-dB exchange rate correlated well with hearing loss. Dear 
    claimed that for every study which supports the 3-dB exchange rate, 
    another supports the 5-dB exchange rate. Dear further contended that a 
    3-dB exchange rate was valid only for workplaces with no intermittent 
    noise exposure, which is a condition that rarely exists in American 
    workplaces.
        Sataloff et al. (1984) studied the effect of intermittent noise 
    exposure on the hearing acuity of workers. This study corroborates an 
    earlier report, done by Sataloff et al. (1969) on the hearing acuity of 
    rock-drilling miners, that intermittent noise is not as hazardous as 
    continuous noise of the same intensity. In the more recent study, 295 
    industrial workers who did not use hearing protectors were exposed to 
    non-impact sound levels from 99 dBA to 118 dBA with quiet periods less 
    than 90 dBA. Most of the workers were exposed to the higher sound 
    levels. The researchers concluded that intermittent noise exposure 
    produced little hearing loss at frequencies below 3000 Hz; however, it 
    produced substantial damage at the higher frequencies. The pattern of 
    damage, exhibited by workers exposed to continuous noise, was also 
    realized at the lower audiometric frequencies. The researchers 
    attributed the difference in patterns of damage to the recovery of the 
    hair cells in the cochlea during quiet periods in the workers exposure 
    to intermittent noise.
        Sataloff et al. (1984) also compared the hearing loss of a 
    population of 295 workers exposed to intermittent noise to other 
    studies on workers exposed to continuous noise conducted by Royster et 
    al., Botsford, and Johnson and Harris'
    
    [[Page 66398]]
    
    review of Baughn's findings. Sataloff et al. asserted that the 
    comparison indicated that workers exhibited more hearing loss when 
    exposed to continuous noise than from exposures to intermittent noise. 
    Although research showed that the loss caused by intermittent noise 
    differs substantially from the effects of continuous noise of the same 
    intensity, Sataloff et al. did not state an opinion as to which 
    exchange rate is most appropriate.
        Hodge and Price (1978), in their review of damage risk criteria, 
    summarized that the 3-dB exchange rate was proposed to account for 
    variations in exposure time to both intermittent and continuous noise 
    and that the 5-dB exchange rate was proposed to account for the 
    ``beneficial effect of recovery'' during quiet periods between such 
    exposures. They stated, however, that the sound level would need to 
    fall below 60 dBA to effect recovery. They concluded that neither the 
    3-dB nor 5-dB exchange rate fits the hearing loss at all frequencies or 
    under all conditions and there will be controversy in this area for 
    many years to come.
        Cluff (1982), professor of audiology at Arizona State University, 
    states that:
    
    * * * while equinocivity (the principle embodied in the 5-dB 
    doubling rate) may be an applicable basis for determining noise dose 
    for lower levels of noise, its credibility suffers as the level of 
    the noise increases above 90 dBA. * * * The only justification for 
    equinocivity, in lieu of equal energy [3-dB exchange rate], is that 
    on-the-job exposure to noise will probably be intermittent. * * * 
    Applying the above logic to very high noise levels [sound levels], 
    intermittent exposure may be claimed for noise levels of 115 dBA, 
    for instance, only if the duration of each individual exposure is 
    substantially shorter than the approximately two minute maximum that 
    would be allowed under equal energy.
    
        Bies and Hansen (1990) developed an equation fitting a 6-dB 
    exchange rate to the ISO 1999: 1990(E) data, instead of the 3-dB 
    exchange rate as presented by ISO. Essentially, they showed that the 
    mathematical solution fitting an equation to the hearing loss data 
    contained in ISO 1999: 1990(E) is not unique.
        Macrae (1991) published an article which refutes Bies and Hansen's 
    findings. Macrae studied people with a sensorineural hearing loss at 
    4000 Hz to determine the progression of the loss in relation to 
    presbycusis. Macrae's data supported ISO 1999 which uses a 3-dB 
    exchange rate. Macrae believed that Bies and Hansen erred by assuming 
    that hearing loss, due to presbycusis and noise exposure, was additive 
    on an antilogarithmic basis at 4000 Hz. Because the progression of 
    hearing loss at other frequencies was not studied, Macrae could not 
    reach any definite conclusions as to the progression of hearing loss at 
    frequencies other than 4000 Hz.
        According to the Committee on Hearing, Bioacoustics, and 
    Biomechanics of the National Research Council (CHABA) (1993), the data 
    for specifying an exchange rate were not conclusive.
        Compared to steady-state noise data, little data exist on the 
    effect of intermittent or time varying noise exposure. Depending upon 
    the length of time of the exposure, an exchange rate of between 0-dB 
    and 8-dB is appropriate. Each of these single number exchange rates is 
    valid for a limited set of exposure conditions. Therefore, CHABA did 
    not recommend an exchange rate. Additionally, CHABA concluded that the 
    maximum sound level for effective quiet is approximately 80 dBA at most 
    frequencies.
        NIOSH (1995) recommends a 3-dB exchange rate based upon the latest 
    scientific data. This recommendation represents a change in NIOSH's 
    position on exchange rate from that included in the 1972 Criteria for 
    Recommended Standard * * * Occupational Exposure to Noise.
        NIOSH presents many reasons for this change in position. In their 
    1972 criteria document, NIOSH based the recommendation for a 5-dB 
    exchange rate on earlier recommendations of CHABA (Kryter et al., 
    1966). CHABA's 1966 recommendations were predicated on three 
    postulates, which included--
        (1) TTS2 (temporary threshold shift measured two minutes after 
    cessation of the noise exposure) is a valid predictor of permanent 
    threshold shift (PTS);
        (2) equivalent TTS2's obtained from exposures were equally 
    hazardous; and
        (3) TTS2 is a consistent measure of the effects of a single 
    day's exposure to noise.
        Since that time, NIOSH believes that more recent scientific studies 
    have proven these postulates to be erroneous. Another assumption that 
    NIOSH found for justifying the 5-dB exchange rate was that 
    interruptions will be of ``equal length and spacing so that a number of 
    identical exposure cycles are distributed uniformly throughout the 
    day.''
        Although NIOSH found that intermittent noise exposure is less 
    harmful than continuous noise exposure, NIOSH has determined that the 
    beneficial effects of intermittency which allow for recovery from TTS 
    are not found in industry today. The quiet periods are too loud and too 
    short to permit recovery of TTS before the next exposure to harmful 
    noise.
        NIOSH cites field studies by Sataloff et al. (1969), Holmgren et 
    al. (1971), Johansson et al. (1973), and Institut National de Recherche 
    et de Securite (1978), to show the beneficial effect of intermittency 
    of noise exposure in mining and forestry. Studies by NIOSH (1976), 
    NIOSH (1982), Passchier-Vermeer (1973) and Shaw (1985), not supporting 
    this finding were also cited. NIOSH, however, concludes that ``the 
    ameliorative effect of intermittency does not support the use of the 5-
    dB exchange rate.''
        The Shaw study (1985) supports the 3-dB exchange rate based on the 
    premise that a 3-dB exchange rate better fits the epidemiological data 
    on the relationship between noise exposure and hearing loss. Shaw also 
    criticizes the use of the 5-dB exchange rate because it was based upon 
    the assumption that a permanent threshold shift (PTS) is related 
    directly to temporary threshold shift (TTS). Shaw believes that no 
    researcher has adequately demonstrated a relationship between PTS and 
    TTS. Furthermore, he states that the 5-dB exchange rate does not take 
    into account variations in the temporal pattern of exposure.
        Suter (1983) conducted a comprehensive review of the literature on 
    exchange rate. She concluded that the 5-dB exchange rate is under-
    protective in many situations and that the 3-dB exchange rate is more 
    firmly supported by the scientific evidence for assessing hearing 
    impairment as a function of sound level and duration. Suter, however, 
    stated that:
    
        The situation becomes more complex when noise becomes truly 
    intermittent, in other words, when there are large differences 
    between high and low levels, and levels in between occur rarely. The 
    studies of forestry workers and miners [Sataloff et al. 1969; 
    Holmgren 1971; Johansson 1973; and Institute National de Recherche 
    et de Securite 1978] indicate that the frequent periods of quiet 
    between noise bursts can in some circumstances, ameliorate the 
    effects of noise exposure.
    
        Regarding the literature review, Suter explained that the 
    researchers' findings have been refuted by two NIOSH studies of 
    intermittently exposed coal miners (NIOSH, 1976) and firefighters 
    (NIOSH, 1982). In addition, the researchers' studies suffer from 
    various methodological problems such as inadequate characterization of 
    exposure, sporadic wearing of hearing protectors, small sample size, 
    etc. Nevertheless, Suter believed that these studies show a valid 
    trend, in that the intermittency of exposure can offset the effects of 
    noise exposure, especially in view of
    
    [[Page 66399]]
    
    some of the animal studies (Ward and Turner, 1982). Suter further 
    stated that:
    
        The logical consequence of such a trend [intermittent noise 
    exposure being less hazardous than continuous noise exposure] would 
    be to allow an adjustment to the maximum permissible exposure limit 
    for outdoor, intermittent noise exposure. This is by contrast to a 
    5-dB exchange rate, for which there is virtually no scientific 
    justification * * *.
    
        Suter suggested using a 3-dB exchange rate along with an adjustment 
    of 2 dB to the PEL for outdoor noise. She stated that ``The exact 
    amount of such an adjustment should await clarification by further 
    scientific evidence.''
        According to Sliney (1993), chair of the ACGIH Physical Agents TLV 
    Committee, (ACGIH) revised its exchange rate from 5-dB to 3-dB, on the 
    basis that the use of a 5-dB exchange rate is not wise for short 
    exposure periods. The ACGIH stated that allowable durations for high 
    sound levels which are permitted with a 5-dB exchange rate are 
    excessive. In addition, ACGIH believed that, with a 3-dB exchange rate, 
    an upper limit for the TLV was capped by a 140 dBC impulse peak sound 
    pressure level. Both the 1971 and 1990 versions of the ISO 1999 
    standard employ the 3-dB exchange rate.
        Evans and Ming (1982) studied five groups of employees in noisy 
    occupations using personal noise dosimeters which integrated sound 
    levels based on a 3-dB exchange rate. The noise exposures ranged from 
    80 dBA to 102 dBA. They used a mathematical model developed by Robinson 
    and Shipton based upon a 3-dB exchange rate for predicting hearing loss 
    among exposed workers. Evans and Ming stated that the observed noise-
    induced hearing loss (NIHL) of workers in the spinning, weaving, and 
    bottling industries agreed with those predicted by Robinson and 
    Shipton's model. The hearing loss of workers in the metal-work 
    industry, however, tended to be greater than those predicted. The 
    authors believed that the significant amount of impulse noise 
    contributing to the noise exposures in this industry explained the 
    difference. Evans and Ming concluded that the use of Robinson and 
    Shipton's prediction method is valid for predicting the hearing loss 
    risk for various noise exposures.
         As will be displayed later in Tables III-4 and III-5, the 3-dB 
    exchange rate is also used by many international communities and 
    selected branches of the U.S. armed services.
        Although occupations in the mining industry are typically exposed 
    to varying sound levels, most miners are continuously exposed to noise 
    above 80 dBA. Because the majority of exposures are continuously above 
    80 dBA, little or no time is available to permit ``recovery time'' from 
    TTS. Thus, miners experience little recovery from the effects of these 
    noise exposures. ``Recovery time'' is a basic tenet of the current 5-dB 
    exchange rate; thus, the Agency has concluded the continuous nature of 
    noise exposure in the mining industry is more realistically 
    characterized by the 3-dB exchange rate.
        Although the Agency has reached this conclusion, and although there 
    appears to be a growing consensus supporting the use of a 3-dB exchange 
    rate among the scientific community, international regulators, and the 
    U.S. armed services, MSHA has chosen to retain a 5-dB exchange rate for 
    its proposal because there are significant feasibility implications of 
    adopting a 3-dB rate--both economic and technological.
        With respect to economic feasibility, MSHA conducted a study of the 
    effect of a 3-dB exchange rate on the measured noise exposure of U.S. 
    metal and nonmetal miners. The mine inspectors collected measurements 
    during the course of their regular inspections using personal noise 
    dosimeters which collected data using 5-dB and 3-dB exchange rates 
    simultaneously. These data are presented in Table III-2.
    
      Table III-2.--M/NM Samples a Exceeding Specified Sound Levels Collected by MSHA From May 1995 to October 1995 
    ----------------------------------------------------------------------------------------------------------------
                                                                     5-dB exchange rate        3-dB exchange rate   
                                                                 ---------------------------------------------------
                        Sound level (in dBA)                       Number of    Percent of   Number of    Percent of
                                                                    samples      samples      samples      samples  
    ----------------------------------------------------------------------------------------------------------------
    90..........................................................          491         16.5         1483         49.9
    85..........................................................  ...........  ...........         2543         85.5
    ----------------------------------------------------------------------------------------------------------------
    a Total of 2974 samples. Two of the boxes in the table do not contain entries. This is to avoid the potential   
      for making an inappropriate comparison of values. Direct comparison of TWA8 values determined with different  
      thresholds is not appropriate if the TWA8 is less than one of the thresholds. An example may help to          
      illustrate the point. A miner exposed to a constant sound field of 85 dBA for 8 hours would be determined to  
      have a noise dose of 0%, or a TWA8 of 0 dBA, if a 90 dBA threshold is used: none of the sound would be counted
      in the computation. If the exposure was measured using an 80 dBA threshold, the dose would be 50%, or a TWA8  
      of 85 dBA. Contrasting the measures taken with the two thresholds would be inappropriate in such a case.      
    
        The measurements in Table III-2 for a 5-dB exchange rate were made 
    using a 90-dBA threshold while the 3-dB exchange rate data were 
    obtained without a threshold. To get a better picture of the impact of 
    moving from a 5-dB exchange rate to a 3-dB exchange rate if, as 
    proposed, the Agency adopts an 80-dBA threshold, Table III-3 has been 
    constructed. The data for the 5-dB exchange rate comes from the 
    Agency's dual-threshold survey for metal and nonmetal mines, presented 
    in Table II-11. This also allows for the analysis of data at values 
    below a TWA8 of 90 dBA, something which is not possible with a 90 
    dBA threshold. The data for the 3-dB exchange rate come from Table III-
    2--switching to an 80 dB threshold does not significantly change the 3-
    dB readings in Table III-2.
    
    Table III-3.--Metal/Nonmetal Samples Exceeding Specified Sound Levels at
                            Different Exchange Rates                        
    ------------------------------------------------------------------------
                                       5-dB                                 
    -------------------------------------------------      3-dB percent     
      Sound level (in dBA)            Percent                               
    ------------------------------------------------------------------------
    90.....................              26.9                     49.9      
    85.....................              67.6                     85.5      
    ------------------------------------------------------------------------
    
        As indicated in Table III-3 the selection of an exchange rate 
    substantially affects the measured noise
    
    [[Page 66400]]
    
    exposure. The percentage of miners whose noise exposure would exceed a 
    PEL set at a TWA8 of 90 dBA (or an LEq,8 of 90 dBA in the 
    case of a 3-dB exchange rate) increases from 26.9% to 49.9% when the 
    exchange rate changes from 5-dB to 3-dB. Looking at the numbers another 
    way, as compared with using a 5-dB exchange rate, using a 3-dB exchange 
    rate would result in the need to utilize engineering or administrative 
    controls to limit the exposure of twice as many miners. Moreover, the 
    engineering controls required would be more expensive since it would 
    take a more stringent control to bring down, to the PEL, exposures that 
    double every 3-dB. The table also reveals that to switch to a 3-dB 
    exchange rate and setting the PEL at an Leq,8 of 85 dBA would 
    increase the percentage of miners whose exposure is out of compliance 
    with the PEL from 67.6% to 85.5%.
         MSHA has not compiled similar data for coal mining, although the 
    consequences would be similar. Accordingly, MSHA believes that using a 
    3-dB exchange rate would have significant implications for the U.S. 
    mining industry.
        With respect to technological feasibility, it is extremely 
    difficult to reduce the noise exposures to a Leq,8 of 90 dBA using 
    currently available engineering or administrative noise controls or a 
    combination thereof. For many pieces of existing equipment it is not 
    practical to apply engineering controls without seriously compromising 
    the equipment's operational capacity.
        Accordingly, as discussed in part IV of this preamble, moving the 
    industry to a 3-dB exchange rate may be infeasible at this time.
        MSHA believes that the determination of an appropriate exchange 
    rate is one of the more noteworthy issues in the proposed rule. 
    Accordingly, MSHA requests further comment and data on this issue. In 
    particular, MSHA notes that the studies supportive of a 5-dB rate are 
    generally dated, and requests information about any more current study 
    supporting that exchange rate.
    A-weighting, slow-response
        Proposed Sec. 62.120(a)(3)(iv) requires that the instruments used 
    for measuring noise exposures be set for the A-weighting network and 
    slow-response (exponential time averaging). This is identical to the 
    existing MSHA regulations for exposures to non-impulse/impact noise. 
    OSHA also uses the A-weighting network and the slow-response time for 
    evaluating exposure to noise.
        Weighting networks were designed to approximate the response of the 
    human ear to tones of equal loudness. The human ear does not respond to 
    all levels of tones in the same way. At low sound pressure levels 
    (e.g., 50 dB) the ear discriminates against low-frequency and high-
    frequency tones. At higher sound pressure levels (e.g., 90 dB), the ear 
    no longer discriminates against low- and high-frequency tones. Although 
    the human ear does not discriminate against low-frequency tones at high 
    sound levels, the low-frequency tones are less damaging to hearing than 
    mid-frequency tones.
        Several weighting networks have been developed to take these 
    differences into account: known as A, B, and C. Early researchers 
    suggested using them all in combination: the A-weighting network when 
    the sound pressure level was less than 55 dB, the B-weighting network 
    between 55 and 85 dB, and the C-weighting network for sound pressure 
    levels exceeding 85 dB (Scott, 1957). Since that time, however, 
    concensus has developed on the use of the A-weighting network.
        Response time, also known as a time constant, refers to the speed 
    at which the instrument responds to a fluctuating noise.
        There are five responses defined in ANSI S1.4-1983, ``Specification 
    for Sound Level Meters''. They are fast, slow, impulse, exponential, 
    and peak. The quickest response is the peak response and the slowest is 
    the slow. Originally the slow response (1000 milliseconds) was used to 
    characterize occupational noise exposure. This response was used since 
    it was easier to read the needle deflections on a meter in rapidly 
    fluctuating noise. For this type of noise the needle deflections using 
    the fast response (125 milliseconds) were too difficult for the human 
    eye to follow. ANSI S1.25-1991, ``Specification for Personal Noise 
    Dosimeters'', prescribes only the slow and the fast responses for 
    personal noise dosimeters. Many of the older, but not obsolete, 
    personal noise dosimeters only have the slow response. Furthermore, the 
    slow response was used for characterizing the noise exposure when most 
    damage risk criteria were developed.
        Many commenters suggested that MSHA adopt OSHA's instrumentation 
    requirements. This would imply that noise is to be measured on the A-
    weighting network and the slow response. However, one commenter 
    suggested that MSHA use the fast response for evaluating noise 
    exposure, because ``Use of fast response will result in a more accurate 
    assessment of employee exposure.''
        Prior to the adoption of the A-weighting network to evaluate noise 
    exposure, the scientific community used more complex methods (e.g., 
    octave bands and speech interference levels).
        ACGIH (1986) reports that:
    
        * * * Botsford demonstrated that A-weighted levels are as 
    reliable as octave band levels in the prediction of effects on 
    hearing in 80% of the occupational noises considered, and slightly 
    more conservative in 16% of the cases. Passchier-Vermeer and Cohen 
    et al. similarly demonstrated that A-weighted levels provide a 
    reasonable estimate of the hazard to hearing in most industrial 
    environments.
    
        The National Safety Council's Book, Fundamentals of Industrial 
    Hygiene, Fourth Edition (Plog et al., 1995) states that:
    
        The A-weighted sound level measurement has become popular in the 
    assessment of overall noise hazard because it is thought to provide 
    a rating of industrial broadband noises that indicates the injurious 
    effects such noise has on the human ear.
    
        NIOSH (1972) recommended the continued use of the A-weighted sound 
    level measurement in its criteria document for a recommended standard 
    on occupational noise exposure. In this criteria document they state:
    
        As a result of its simplicity and accuracy in rating hazard to 
    hearing, the A-weighted sound level was adopted as the measure for 
    assessing noise exposure by the American Conference of Governmental 
    Industrial Hygienist (ACGIH) and by Intersociety Committee 
    consisting of representatives from the American Academy of 
    Occupational Medicine, American Academy of Ophthalmology and 
    Otolaryngology, ACGIH, Industrial Hygiene Association, and the 
    Industrial Medical Association. A-weighted sound level measurement 
    was adopted by the U.S. Department of Labor as part of the 
    Occupational Safety and Health Standards and by the British 
    Occupational Hygiene Society in its Hygiene Standards for Wide-Band 
    Noise.
    
        In reviewing the procedures for exposure measurement in regulations 
    and codes of practice (mandatory or recommended) from the EEC, the ISO, 
    the international community, and selected branches of the U.S. armed 
    services (see Tables III-4 and III-5), MSHA found that there is general 
    agreement among these groups that measurements be taken using the A-
    weighting network and most agree to use the slow-response instrument 
    settings. ISO 1999 (1990) recommends that if sound level meters are 
    used to measure noise exposure, then the instrument should be set on A-
    weighted, fast-response. In Australia, integrating sound level meters 
    should be
    
    [[Page 66401]]
    
    set to fast-response while other sound level meters should be set to 
    slow-response.
        The scientific community and most regulatory entities around the 
    world accept the A-weighting network and slow-response time as 
    appropriate measurement parameters for characterizing noise exposures. 
    These parameters have been used by the U.S. Department of Labor, since 
    the adoption of the Walsh-Healey Public Contracts Act noise regulations 
    of 1969.
        Based upon comments and the good correlation between hearing loss 
    and A-weighted noise exposures, MSHA proposes to continue using A-
    weighting and slow-response when determining a miner's noise exposure.
    Action Level
        Proposed Sec. 62.120(b) establishes an ``action level'' at a 
    TWA8 of 85 dBA.
        The need for an action level reflects two facts: 1) there is a 
    significant risk of material impairment to miners from a lifetime of 
    exposure to noise at this level; and 2) the Agency believes it may not 
    be feasible at this time to lower the PEL to this level, since that 
    would require that mine operators use all feasible engineering and 
    administrative controls to reduce noise exposures to this level.
        The proposal would require that all miners exposed above the action 
    level be provided special instruction in the hazards of noise and 
    protective methods. The training is to be provided annually for as long 
    as exposure exceeds the action level. (The nature of this instruction, 
    how it is to be provided, and how it can be coordinated with other 
    required miner training are subjects discussed in connection with 
    proposed Sec. 62.130.)
        If a miner's exposure exceeds the action level but is below the 
    PEL, an operator will also be required to enroll a miner whose exposure 
    exceeds the action level in a hearing conservation program (HCP). While 
    enrollment in the HCP would require the operator to make annual 
    audiometric testing available to the miner, miners exposed to noise 
    below the PEL would have the right to decline taking any annual 
    audiometric testing. MSHA's proposed testing requirements related to 
    the action level are consistent with those of the OSHA HCP. The 
    requirements for such testing are discussed in connection with proposed 
    Sec. 62.140, audiometric testing program.
        MSHA is seeking comments on how to minimize the burden on mine 
    operators of providing audiometric examinations for those miners with 
    only a temporary attachment to the mining work force (e.g. summer 
    employees), while recognizing the importance of detecting and tracking 
    hearing loss among those who switch jobs.
        In addition, the operator must provide properly fitted hearing 
    protection--before the initial hearing examination, if a significant 
    threshold shift in hearing acuity is detected, and at any other time 
    upon miner request. Should it take more than 6 months to provide the 
    initial hearing examination because of the need to wait for a mobile 
    test van, or should a significant threshold shift in hearing acuity be 
    detected, the operator would also be required to ensure that the miner 
    wears the hearing protection--even if the miner's noise exposure 
    remains under the PEL. (A discussion of the time frames for audiometric 
    tests, and the use of mobile test vans, is included in the discussion 
    of proposed Sec. 62.140, audiometric testing program. The definition of 
    a significant threshold shift is discussed in connection with proposed 
    Sec. 62.160, evaluation of audiogram.)
        An action level currently exists under OSHA but would be new to the 
    mining industry. As discussed herein, MSHA proposes to build upon the 
    requirements which have been used by OSHA while giving due regard to 
    implementation approaches appropriate to the circumstances of the 
    mining community.
    Comments on Action Level
        Several commenters recommended an action level of 85 dBA for 
    triggering the requirements of an HCP.
        Many of those who commented in response to MSHA's ANPRM discussed 
    hearing protection and audiometric testing. Some of these comments shed 
    light on the relationship and comparative benefits of these approaches.
        Some commenters supported the use of hearing protectors as an 
    integral part of an HCP, while other commenters recommended that 
    hearing protectors be supplied even when not required so as to afford 
    greater protection. Other commenters expressed three common concerns 
    over the use of hearing protectors--
        (1) difficulty with speech communication and the masking of warning 
    signals (roof talk, backup alarms, etc.), especially for those miners 
    with a pre-existing hearing loss;
        (2) miner acceptance, including comfort; and
        (3) personal hygiene.
        The latter two issues of miner acceptance and personal hygiene are 
    discussed in detail in the sections of the preamble entitled Selection 
    of hearing protectors and Maintenance of hearing protectors, 
    respectively (in connection with proposed Sec. 62.125).
        Several commenters suggested alternatives for dealing with 
    communication problems associated with the use of hearing protectors by 
    those with a hearing loss or in the presence of background noise. These 
    alternatives included use of a ``buddy'' system, visual warnings, 
    communication headsets, vitro-tactile warning systems, flat-frequency 
    response hearing protectors, and notch-amplification earmuffs.
        Many commenters specifically mentioned the problem of miner 
    acceptance of hearing protectors. One of these commenters stated: ``* * 
    * there is anecdotal reporting to suggest that miners resist wearing 
    hearing protective devices.''
        One commenter stated: ``Another [usage] problem may be the use of 
    muffs with additional safety equipment, e.g. hard hats and safety 
    glasses, that may be required for use by the miners.'' Other commenters 
    either had no problems with hearing protectors or felt that any 
    problems could be overcome with the proper training.
        In addition to the comments received in response to MSHA's ANPRM on 
    this issue, several researchers and organizations have taken a position 
    in regard to the use of hearing protectors.
        Shaw (1985) reviewed much of the same literature as OSHA when the 
    1983 Hearing Conservation Amendment was prepared. Shaw's study supports 
    requiring both hearing protectors and an HCP for exposures exceeding 85 
    dBA.
        In Communication in Noisy Environments (Coleman et al., 1984), the 
    authors state that:
    
        * * * excessive attenuation needs to be minimized and the 
    frequency response of the protector is of particular importance in 
    this respect. * * * (S)everal authors * * * suggest that a protector 
    which passed relatively more low frequencies could increase remote 
    masking and produce potential communication difficulties for some 
    members of the population. This effect has been demonstrated to be 
    of practical significance for coal mining conditions * * * A flat 
    frequency response for a protector is necessary to counter the 
    effect.
    
        Michael (1991) recommends that the hearing protector attenuate the 
    noise with an adequate margin of safety; however, the hearing protector 
    should not unnecessarily reduce important aural communications. To 
    accomplish this goal, the hearing protector's attenuation 
    characteristics should be matched to the noise exposure spectra as 
    close as possible. This way the hearing protector will minimally change
    
    [[Page 66402]]
    
    the worker's perception of the noise. Michael also points out that 
    overall noise reduction achieved by a hearing protector can be 
    substantially influenced by the spectra of the noise.
        Chiusano et al. (1995) reported that a communication headset, 
    without gain limiters, can expose communication workers to hazardous 
    sound levels. The noise exposures ranged from 79.9 dBA to 103.8 dBA, 
    with the average exposure being 87.0 dBA. Furthermore, the peak sound 
    pressure levels ranged from 119.2 dB to 148.8 dB, with the average 
    being 140.8 dB. Some recommendations presented by the authors to 
    control the noise exposure were to include peak clipping, bandwidth 
    limitations, signal compression, computerized gain control, and 
    improving the signal to noise ratio.
        In the CAOHC Manual, Miller (1985) states that many authorities 
    consider OSHA's requirement on who must wear hearing protectors to be 
    ``unwieldy.'' This manual states further that ``A more practical and 
    workable approach is to require all workers exposed to levels of 85-dBA 
    or higher to use PHPD's [personal hearing protection devices] 
    regardless of whether the audiograms show an STS.''
        According to Suter (1986): ``Because hearing loss may occur in 
    people chronically exposed to levels of 85-dBA and above, it is wise to 
    use protectors that attenuate to 85-dBA in all cases.''
        The U.S. Armed Services, as well as the European Economic Community 
    and other foreign countries, require the use of hearing protection when 
    sound levels exceed 85 dBA.
    
    General Discussion of Action Level and Requirements
    
        The Agency has concluded that there is a significant risk of 
    material impairment to miners from a lifetime of exposure to noise at a 
    TWA8 of 85 dBA. In mining, the first line of defense against risks 
    has always been training. Accordingly, the proposal provides for annual 
    instruction--to enhance awareness of noise risks, operator 
    requirements, and available controls. This training would be required 
    for any miner whose exposure is above the action level.
        MSHA's requirements for this training, and a discussion of how it 
    can be coordinated with existing training requirements, are in proposed 
    Sec. 62.130. As discussed below in connection with that section, MSHA 
    received many comments in response to its Advance Notice of Proposed 
    Rulemaking that supported the value of an annual training requirement. 
    Studies have shown that the effectiveness of a hearing protection 
    program is highly dependent on the proper use of hearing protectors and 
    the commitment of both management and employees, and annual training is 
    critical to reinforce both the knowledge and commitment.
        The Agency believes it may not be feasible at this time to require 
    mine operators to reduce noise exposures to a TWA8 of 85 dBA. A 
    detailed discussion on this point can be found in Part IV of this 
    preamble. Thus, for exposures between a TWA8 of 85 dBA (the action 
    level), and a TWA8 of 90 dBA (the PEL), the available tools to 
    supplement training are limited to hearing protectors and annual 
    audiometric examinations.
        Hearing protectors offer only limited noise protection. As 
    discussed in detail in connection with proposed Sec. 62.125, studies 
    indicate that hearing protectors may provide significantly less than 
    their rated protection under actual mining conditions. Nevertheless, 
    MSHA believes that if hearing protection is properly utilized--that is, 
    if the requirements under proposed Sec. 62.125 are implemented--they 
    generally can be relied on to provide at least 5 dBA attenuation, and 
    thus could realistically protect the majority of miners whose noise 
    exposure falls between the action level and the PEL.
        The comments that MSHA received in response to its ANPRM, however, 
    suggest that ensuring the protectors are properly fitted, maintained 
    and utilized may continue to prove difficult--even once the proposed 
    new standards in this regard (see the discussion of proposed 
    Sec. 62.125) are taken into account. For example:
        (1) The mining environment presents hazards which require a miner 
    to be aware of his/her surroundings. Many underground miners claim that 
    the use of hearing protectors interferes with their ability to hear 
    warning signals or roof talk. This interference may be particularly 
    pronounced among miners who already have a significant degree of 
    hearing loss, and such miners may justifiably be reluctant to use 
    hearing protectors;
        (2) Hearing protectors (earmuffs and earplugs) are difficult to 
    keep clean in the mining environment which can lead to irritation or 
    infection of the ear(s);
        (3) Earmuffs are often uncomfortable when worn in hot environments 
    (e.g., surface mines during periods of extreme heat or some deep 
    underground mines);
        (4) Hearing protectors experience a degradation of attenuation when 
    moved from their original position. This condition can occur often when 
    hearing protectors are worn by a miner operating vibrating equipment 
    (e.g., pneumatic drills, continuous mining machines, mobile equipment), 
    wearing certain types of personal protective gear (e.g., safety 
    glasses, hardhats, respirators, welder's hood, etc.), or sweating;
        (5) The effectiveness of hearing protectors is highly dependent 
    upon proper fit and use by the miner. While the amount of protection 
    afforded by engineering controls can be easily measured, the 
    attenuation of hearing protectors under actual working conditions can 
    only be estimated; and
        (6) Generally, hearing protectors are not effective in reducing low 
    frequency noise. As most mining machinery emits predominantly low 
    frequency noise, the use of hearing protectors may have a negligible 
    effect in reducing the overall sound level.
        To alleviate these problems, both operators and miners must be 
    committed to working through individual concerns about hearing 
    protection. MSHA believes that the best way to facilitate this 
    process--at exposure levels between the action level and the PEL, and 
    with a few exceptions--is to have operators provide instruction and 
    make suitable hearing protectors available to miners upon request. If 
    protectors are requested, they would have to be provided in accordance 
    with the requirements of Sec. 62.125--i.e. a choice of plug or muff 
    type, properly fitted, maintained, and replaced under certain 
    conditions. An operator would generally not, at such exposure levels, 
    have an obligation to enforce the use of hearing protection. MSHA 
    believes that the combination of knowledge, availability, and properly 
    selected, fit and maintained equipment may be the best way to encourage 
    hearing protector use.
        MSHA would require an operator to provide a miner with a hearing 
    protector while awaiting a baseline audiometric examination; but with 
    the exception noted below, the operator would not have to enforce the 
    use of the protector as long as the miner's exposure does not exceed 
    the PEL.
        In two cases, however, MSHA proposes to require operators to 
    enforce hearing protector use at exposures below the PEL. The first 
    case would be in the event a miner exposed above the action level has 
    to wait more than 6 months for a baseline audiometric examination. As 
    noted in proposed Sec. 62.140, the baseline examination is normally to 
    take place within 6 months of a determination that a miner is at risk 
    because his or her exposure exceeds the action level; however, the time 
    frame can be extended for an additional 6 months if the operator has to 
    wait for a
    
    [[Page 66403]]
    
    mobile test van. In such cases, the miner is exposed to harm for an 
    extended period of time without the benefit of audiometric test data, 
    and MSHA believes it would be appropriate to require protection to be 
    worn. This is the approach taken under OSHA's noise requirements.
        In addition, an operator would be obligated to ensure the miner 
    uses provided hearing protection when audiometric examinations indicate 
    a significant threshold shift (STS) in hearing acuity has occurred and 
    the miner's exposure exceeds the action level. (The evaluation of 
    audiograms, and the determination of whether or not there is an STS, is 
    the subject of proposed Sec. 62.160.) MSHA believes that once there is 
    evidence from the tests that the miner is incurring hearing loss, it is 
    appropriate to require that hearing protectors be worn as long as 
    exposure exceeds the action level.
        Annual audiometric examinations cost more than providing hearing 
    protection--but as already recognized by many in the mining industry, 
    and all the industries which operate under OSHA's requirements, such 
    examinations provide important information, especially in an 
    environment in which hearing protector use has the problems noted 
    previously. The act of enrolling miners in a ``hearing conservation 
    program'' (HCP) can help emphasize to those individuals that they 
    should pay more attention to the training and available controls. It 
    also helps miner representatives, operators, and MSHA focus available 
    resources on those miners who have actually suffered an STS at lower 
    noise exposures. While MSHA is not proposing to require operators to 
    compel miners to take the annual examinations at exposure levels below 
    the PEL, and expects that many miners may be reluctant to take 
    examinations out of concern about how the information would be used, 
    MSHA anticipates that over time the required training would lead to 
    growing use of such examinations within the mining industry. (MSHA's 
    preliminary RIA assumes only limited participation at such exposure 
    levels during the initial years of the rule's implementation.)
    Participation in an HCP
        MSHA has no standards addressing hearing conservation plans or 
    programs in its existing metal and nonmetal regulations. However, an 
    indeterminate number of mines have voluntarily established HCP's. MSHA 
    estimates that 5% of small mines, and 20% of large mines, have such 
    programs.
        Existing MSHA coal noise standards require mine operators to submit 
    ``* * * a plan for the administration of a continuing, effective 
    hearing conservation program,'' within 60 days following the issuance 
    of a notice of violation [citation] for subjecting a miner to a noise 
    exposure exceeding the PEL. This plan must include provisions for pre-
    employment and periodic audiograms. The regulation, however, does not 
    specify the procedures nor the time frame for obtaining these 
    audiograms. Additionally, due to coal's policy of considering hearing 
    protector attenuation in determining compliance with the PEL, few 
    miners are found overexposed.
        OSHA's noise standard requires that all employees exposed above the 
    action level (TWA8 of 85 dBA) be enrolled in an HCP. OSHA's HCP 
    requirements include provisions addressing exposure assessment, 
    training, audiometric testing, hearing protectors, notification, and 
    recordkeeping.
        Several commenters recommended requiring an HCP whenever a miner's 
    exposure exceeds a TWA8 of 85 dBA, or equivalently a noise dose of 
    50%.
        Under MSHA's proposal, participation in an HCP would be provided by 
    the mine operator at no cost to the miner. OSHA also specifies that 
    audiometric testing and hearing protectors be provided at no cost to 
    the employees. MSHA intends that the audiometric testing be given 
    during normal working hours (on-site or off-site) and that miners 
    participating in these activities receive wages for the time spent in 
    their involvement. If the audiometric testing is provided off-site, 
    MSHA intends the mine operator to compensate the miners for the 
    additional costs, such as mileage, meals, and lodging, that they may 
    incur.
    Elements of an HCP
        Some of the elements often considered to be part of an HCP are 
    handled through separate, free-standing requirements under MSHA's 
    proposal. These include hearing protection and training, and an 
    employer's obligation to evaluate the noise to which miners are exposed 
    to determine if specified levels are exceeded. Accordingly, the 
    proposal uses the term HCP to refer essentially to annual audiometric 
    testing and required follow up examinations and actions.
        Under OSHA's noise standard, the elements of an HCP include:
        (1) monitoring employee noise exposure;
        (2) wearing hearing protectors;
        (3) education and training; and
        (4) audiometric testing and medical evaluation.
        In its ANPRM, MSHA requested information concerning the elements 
    which would be appropriate for inclusion in an HCP for mining. MSHA 
    received numerous comments concerning this issue. Of these, many 
    supported MSHA's adoption of HCP requirements similar to OSHA's, 
    including:
    
    * * * Assessment, monitoring, engineering and/or administrative 
    controls, hearing protective devices, employee education, 
    audiometric testing, interpretation of audiometric tests and follow-
    up, and appropriate record keeping.
    
        Although there was a consensus among commenters on the elements of 
    an HCP, there was considerable variation in the substantive aspects of 
    these elements. Commenters ranged from wanting more performance 
    oriented requirements to wanting more specific requirements with fewer 
    exceptions than in the existing OSHA rule.
        One commenter wanted ``* * * a more stringent program than the 
    present OSHA HCP * * *''. Another felt that no program should be 
    implemented until ``* * * sufficient evidence and testing demonstrates 
    a need for the program to protect the hearing of miners.'' Another 
    commenter believed that audiograms were a needless expense, but that 
    hearing protectors should be required for all miners exposed to 
    hazardous sound levels. Several commenters believed that HCP's were of 
    no value, stating ``Our experience with HCP's indicates they are wasted 
    bureaucratic red tape and present no benefit to the employees.''
        ``Guidelines for the Conduct of an Occupational Hearing 
    Conservation Program'' (1987) developed by the American Occupational 
    Medical Association's Noise and Hearing Conservation Committee of the 
    Council on Scientific Affairs presents the basic elements of an HCP. 
    They recommend that each program include: (1) measurement of exposure; 
    (2) engineering controls; (3) use of hearing protectors; (4) 
    audiometric testing and medical evaluation; (5) education and training; 
    (6) assessment of program effectiveness; and (7) management support.
        MSHA agrees with the majority of the commenters to the ANPRM. 
    However, as noted, MSHA proposes to require some of these elements 
    through free-standing requirements. Accordingly, the proposal uses the 
    term HCP to refer essentially to annual audiometric testing and 
    required follow up examinations and actions. Overall, the requirements 
    of MSHA's proposal are generally
    
    [[Page 66404]]
    
    consistent with OSHA's current HCP requirements and with the 
    requirements of the U.S. armed services and the international 
    community.
        MSHA reviewed HCPs in effect at a variety of organizations. The 
    HCPs consist mainly of monitoring employee noise exposure, controlling 
    the noise, training employees, and conducting audiometric testing. The 
    Agency believes that when engineering and administrative controls are 
    not able to reduce a miner's exposure to within the PEL, annual 
    audiometric testing and medical evaluation would enable mine operators 
    and miners to take proper precautions to identify early hearing loss 
    and thereby prevent further deterioration of hearing. This is discussed 
    in more detail in those sections of the preamble reviewing the proposed 
    HCP requirements (proposed Sec. 62.140 et. seq.).
    Effectiveness of HCP's
        Although many commenters to MSHA's ANPRM stated that an HCP is 
    needed, only a few commenters specifically addressed the effectiveness 
    of an HCP.
        One commenter referenced a study (ANSI, 1990; Royster and Royster, 
    1988) which indicated that the HCP at five out of 17 companies, or less 
    than 30%, could be considered effective/adequate. This inadequacy, 
    however, could be attributed to a lack of commitment by the companies 
    in carrying out all of the necessary components of the HCP. This study 
    found that, for the HCP to be successful, it is critical that a single 
    individual have control over the program and its implementation. 
    Furthermore, management must make a commitment to ensure that the 
    program is fully implemented.
        Another commenter, representing nonmetal mining companies, 
    indicated that its members have not experienced large numbers of claims 
    for hearing loss and this may be a reflection of program effectiveness.
        In addition to the above comments, MSHA reviewed several studies 
    regarding the effectiveness of HCP's. Villeneuve and Caza (1986) 
    reported on the HCP for a Canadian mining company. Under this HCP, 
    miners undergo audiometric evaluations, receive training, and wear 
    hearing protectors. After ten years, the incidence of workers' 
    compensation claims for hearing loss has diminished.
        After obtaining audiometric data from three Ontario employers who 
    had HCP's, Abel and Haythornthwaite (1984) investigated the progression 
    of NIHL. Workers for the first employer (public utility) had their 
    maximum hearing loss between 2000 and 6000 Hz. Further, 78% of the 
    workers who reported never wearing their hearing protectors experienced 
    25 dB of hearing loss at 4000 Hz. For those workers who wore their 
    hearing protectors at least half of the time, 38% had the same degree 
    of hearing loss.
        At the second employer (mining company) about half the drillers 
    incurred a hearing loss of 1 dB per year or more at 4000 Hz. Motorman 
    chute blasters incurred an average change of hearing of a little over 1 
    dB per year. This compares to a hearing loss of 0.5 dB per year for the 
    control group. Further, in subjects who were over 50 years of age, 
    100%, 88% and 38% of the drillers, the motorman chute blasters, and the 
    controls respectively had a hearing loss that exceeded 25 dB at 4000 
    Hz.
        Finally, workers at a foundry and steel mill showed a 0.13 dB per 
    year hearing loss at 1000 Hz and 1.3 dB per year at 4000 Hz. Their 
    hearing loss was similar to the miners.
        Abel (1986) reported on the progression of NIHL among three groups 
    of workers, including miners. All noise-exposed workers had exposures 
    exceeding 85 dBA and were enrolled in an HCP. One requirement of the 
    HCP was mandatory use of hearing protectors. At 4000 Hz, the noise-
    exposed workers lost their hearing acuity at 1.5 dB per year compared 
    to 0.5 dB per year for the control group, who were office workers.
        Despite mandatory use of hearing protectors, most workers in the 
    Abel study admitted to wearing their hearing protectors less than 50% 
    of the time. Further, many modified their hearing protectors to provide 
    greater comfort. Many of the modifications had a deleterious effect on 
    the attenuation.
        Gosztonyi (1975) reported on his evaluation of an HCP at a large 
    manufacturing plant. The study covered a 5-year period (1969-1974) 
    shortly after the passage of the Walsh-Healey Public Contracts Act 
    noise regulations. The study covered 213 employees with a median age of 
    43 years. The workers were divided into three groups based on their 
    noise exposure. These were: (1) 71 office workers exposed to sound 
    levels of 50 to 70 dBA; (2) 71 workers in the machine shop exposed to 
    sound levels of 80 to 85 dBA; and (3) 71 workers (wearing hearing 
    protectors) in the chipping and grinding areas of the iron and steel 
    foundry exposed to sound levels of 100 to 110 dBA. Gosztonyi found 
    that, over a 5-year period, the hearing loss incurred by workers in 
    group (3) were no greater than the losses exhibited by the other groups 
    at each frequency, regardless of the baseline hearing thresholds. He 
    concluded that an HCP (consisting of periodic noise exposure 
    assessments, annual audiometric testing, and the mandatory use of 
    hearing protectors) instituted when noise exposures exceed a hearing 
    conservation criterion of approximately 90 dBA adequately protects the 
    hearing of noise-exposed workers.
        Pell and Dear (1989) reported the following:
    
        Two longitudinal studies of changes in hearing threshold levels 
    and one study of the prevalence of hearing impairment in noise 
    exposed and non-exposed workers have clearly indicated that DuPont's 
    hearing conservation program has been effective in preventing 
    occupationally noise-induced hearing loss [NIHL].
    
        Several reports on the effectiveness of DuPont's HCP have been 
    published. DuPont's HCP requires the wearing of hearing protectors in 
    high noise areas, audiometric testing, and monitoring of noise 
    exposure. In the first study Pell (1972) showed, via a retrospective 
    study, that the hearing of workers was being protected. The hearing 
    levels of workers in high noise areas were compared to the hearing 
    levels of workers in quieter areas (below approximately 90 dBA). Both 
    groups of workers had comparable hearing levels at frequencies between 
    500 and 2000 Hz. At higher frequencies the median hearing level of 
    quieter area workers was slightly better than the median hearing level 
    of high noise area workers. Although the differences were statistically 
    significant, the author believed that the small differences lacked 
    practical importance. Moreover, the difference was much less than the 
    hearing loss which occurred due to presbycusis and other non-
    occupational factors. Comparing the results to a study published by 
    Nixon and Glorig (1961) on unprotected workers, Pell concluded that the 
    DuPont workers experienced much less hearing loss.
        Later, Pell (1973) published the initial results of a 5-year 
    longitudinal study on the same workers. The sound level to which 
    workers were exposed in the quiet areas could approach 90 dBA, but most 
    exposures were between 50 and 70 dBA. The workers in the highest noise 
    areas were required to wear hearing protectors and most of the workers 
    in the moderate noise areas chose to wear hearing protectors. A 
    comparison of workers' hearing levels at 3000, 4000, and 6000 Hz 
    revealed that there was no increased hearing loss among workers who 
    wore hearing protectors in high noise areas versus the workers in the 
    quiet areas. The researcher concluded that:
    
    
    [[Page 66405]]
    
    
        The analysis of changes in hearing threshold levels over a 5-
    year period has clearly indicated that persons who work in areas 
    where noise levels (sound levels) exceeded 90 dBA showed hearing 
    losses that were no greater than those experienced by persons who 
    worked in areas where the noise levels (sound levels) were less than 
    90 dBA. It is evident, therefore, that a hearing conservation 
    program in which the hearing conservation criterion is approximately 
    90 dBA can successfully protect the hearing of noise-exposed 
    workers.
    
        Pell believed that his study confirmed the earlier conclusion that 
    DuPont's HCP was effective in preventing occupational hearing loss. 
    Pell emphasized, however, that this study cannot reveal the effects of 
    these sound levels on hearing acuity but is intended only to evaluate 
    the effectiveness of the HCP. The third study is a continuation of the 
    second study. In this study, Pell and Dear (1988) evaluated the 
    effectiveness of DuPont's HCP over 20 years. However, the study did not 
    involve the same workers over the entire time frame for many reasons. 
    Furthermore, the researchers divided the workers into three categories: 
    workers exposed to noise under 85 dBA; between 85 to 94 dBA; and 95 dBA 
    or higher. The mean differences, over a 3-year period between workers 
    in noisy (over 85 dBA and wearing hearing protectors) and quiet areas, 
    were small. Evaluating the prevalence of hearing impairment using the 
    AAO-HNS 1979 definition showed that the high noise areas had slightly 
    higher prevalence rates of hearing impairment. After adjusting for 
    presbycusis, only 7.1% of the workers in the high noise areas developed 
    a hearing impairment. Pell and Dear concluded that presbycusis was by 
    far the major factor in developing a hearing impairment. Furthermore, 
    independent clinical evaluations of the non-presbycusis cases revealed 
    that socioeconomic factors, (e.g., differences in off-the-job noise 
    exposures and otological disease), may account for much of the excess 
    hearing impairment of the noise-exposed workers. Pell and Dear 
    attributed the effectiveness of DuPont's HCP to educating the workers 
    to the hazards of noise, hearing protector fitting, and supervision. 
    Because of these components, DuPont workers received greater noise 
    reduction from foam earplugs than did workers in other industries. Pell 
    and Dear believe that effective use of hearing protectors is the 
    overwhelming factor in approaching avoidance of problem hearing loss. 
    In addition, Pell and Dear believe that employees exposed above 90 dBA 
    are better protected by using appropriate hearing protectors rather 
    than implementing engineering controls to reduce the noise to 89 dBA or 
    even 84 dBA.
        Savell and Toothman (1987) studied the HCP at a factory. The 
    workers whose time-weighted average noise exposures ranged from 86 to 
    103 dBA were required to wear hearing protectors as a condition of 
    employment which was strictly enforced. These workers were employed 
    between 8 and 12 years. Only the employees with more than 25 months off 
    the job during the course of the study were excluded in order to obtain 
    a large sample (265 workers). The group mean hearing levels from the 
    latest audiograms were compared to the initial audiograms. Savell and 
    Toothman did not find any significant change in hearing acuity over the 
    course of the study. Therefore, they concluded that mandatory use of 
    hearing protectors in an HCP can protect the hearing acuity of workers.
        Bruhl and Ivarsson (1994) conducted a longitudinal study of the HCP 
    at an automobile stamping plant over a 15-year period. The researchers 
    evaluated workers' hearing levels over the frequency range of 2000 to 
    8000 Hz. Workers' hearing levels were compared to the hearing levels of 
    a ``highly screened'' non-noise exposed male population. For sheet 
    metal workers, the HCP reduced the noise-induced permanent threshold 
    shift. Bruhl and Ivarsson concluded that the HCP, which included 
    effective use of hearing protectors and reduction of sound levels, can 
    eliminate occupational NIHL.
        Franks et al. (1989) examined the hearing conservation records of a 
    large printing company with multiple facilities. They examined the 
    records for factors associated with the development of an STS. Franks 
    et al. indicated that ``* * * statistically significant factors 
    associated with Standard Threshold Shift [STS] were from medical and 
    non-occupational noise exposure histories, and not occupational noise 
    exposure.'' In other words, the HCP was effective since the hearing 
    loss developed by the workers was from non-occupational exposures.
        Moretz (1990), reporting on the work of the ANSI S12.12 working 
    group, stated that ``A pilot analysis of industry's audiometric data 
    found that fewer than 20 percent of the programs [HCP's] are 
    effective.'' Moretz further reported that Alice Suter, a member of this 
    ANSI working group, had stated that ``the actual percentage of 
    companies with effective programs is probably even lower * * *,'' 
    because the ANSI working group had looked at data from relatively large 
    companies. Suter thought that smaller companies are less likely to have 
    the resources necessary to operate an effective HCP.
        The National Institutes of Health (NIH), in its Consensus Statement 
    on Noise and Hearing Loss (1990), states that ``many existing hearing 
    conservation programs remain ineffective due to poor organization and 
    inadequately trained program staff.''
        Although evidence indicates that a properly supervised and operated 
    HCP can provide effective protection, in many instances, HCP's have 
    failed due to the lack of necessary supervision and adherence to proper 
    procedures and principles. Furthermore, the studies which showed HCP's 
    to be effective were mainly of short term durations (five years or 
    less). There is a lack of evidence that long term HCP's protect the 
    hearing acuity of workers. Pell and Dear's 20 year study (1988) was in 
    actuality two shorter longitudinal studies covering a five-year period 
    at the beginning of the study and a three-year period at the end. In 
    both of these shorter studies the hearing level of the participants did 
    not change at a rate different from the non-noise exposed controls.
        The two other long-term studies, Bruhl and Ivarsson (1994) and 
    Bruhl et al. (1994) demonstrated that HCP's were effective in reducing 
    noise-induced permanent threshold shift. At the plant both engineering 
    noise control and hearing protectors were utilized to reduce worker's 
    exposure to noise. Therefore, these studies indicate engineering noise 
    control is a necessary component of an effective long-term HCP.
        Rink (1996) studied the hearing loss of workers enrolled in HCPs. 
    Between 1991 and 1995 nearly 590,000 audiograms were given. During the 
    years the percentage of STSs decreased each year--from 4.69% to 1.22%. 
    Further, Rink reported that about 50% of the STS consistent with noise 
    exposure were persistent (confirmed STSs). The remainder were not 
    permanent. Rink concluded that aggressively adhering to and enforcing 
    the hearing conservation policies proposed by OSHA in 1983 can reduce 
    and effectively control NIHL.
        Many of the above studies indicate that an HCP can be effective in 
    preventing hearing loss, but only if management and workers strictly 
    adhere to its requirements. Several of these studies also concluded 
    that engineering controls were a necessary part of an effective HCP. 
    This is not inconsistent with MSHA's conclusions about the
    
    [[Page 66406]]
    
    importance of commitment by both operators and miners.
    Evaluation of HCP Effectiveness
        MSHA has not included a methodology or a requirement for mine 
    operators to test the effectiveness of their HCP's. Currently, both 
    MSHA's Coal and OSHA's noise standards require an effective HCP, but do 
    not specify a procedure for evaluating the effectiveness of the 
    program. Further, Metal and Nonmetal's noise standard has no 
    requirement for an HCP.
        In its ANPRM, MSHA also requested information concerning 
    appropriate methods or requirements for evaluating the effectiveness of 
    HCP's. One commenter felt that evaluation criteria are unnecessary and 
    that the HCP is effective if exposures are reduced. Another commenter 
    stated that uniform evaluation criteria have not been adopted. Another 
    suggested that NIOSH be given the task of evaluating the effectiveness 
    of HCP's for the mining industry.
        A number of commenters believed that it was essential for MSHA to 
    address procedures for evaluating the effectiveness of HCP's. Several 
    of these commenters suggested that MSHA monitor the activities of the 
    ANSI S12.12 Working Group for Evaluation of HCP's and consider using 
    the guidelines established by this group, once they were finalized. 
    ANSI has published a draft standard, ANSI S12.13-1991 Audiometric 
    Database Analysis (ADBA), which describes techniques for evaluating the 
    effectiveness of the HCP's.
        Adera et al. (1993) studied the effect of using ADBA to determine 
    the effectiveness of a utility company's HCP which had 2,317 
    participants. The hearing acuity of the utility workers was compared to 
    the hearing acuity of tobacco company employees (control population). 
    The tobacco company employees were one of the control populations used 
    in developing the draft ANSI standard S12.13-1991. The control 
    population's noise exposure was approximately 87 dBA and they wore 
    hearing protectors consistently. While the ADBA method deemed the HCP 
    acceptable, epidemiological techniques showed the workers to be at risk 
    of developing a hearing loss. The age-adjusted risk of developing a 
    hearing loss was 2.3 times that of the control population.
        Simpson, Stewart, and Hecksel (1992) studied HCP's at 28 small 
    companies representing 2,183 employees of which 865 qualified for ANSI 
    analysis. The researchers concluded that companies with less than 100 
    employees may have difficulty in meeting ANSI S12.13-1991 data 
    requirements for more than two consecutive years of data analyses due 
    to employee turnover and absenteeism. Sample sizes smaller than 30 
    employees are likely to be more sensitive to outlier scores. Smaller 
    sample sizes were also more likely to be rated marginal or unacceptable 
    due to biasing effects of sample size. For 1990, the percent of STS's 
    ranged from 0% to 3.8% at the individual plants. The rate of STS's 
    across all 28 plants was 1.5%.
        Simpson, Stewart and Kaltenbach (1994) investigated early 
    indicators of HCP performance. A total of 27,047 employees (3,245 
    controls and 23,802 subjects) in 21 HCP's were included in the study. 
    The rate of STS in the control groups ranged from 2.5 to 5.7% while the 
    exposed groups had a rate between 4.6 and 28%. Comparing the incidence 
    of STS's with ANSI S12.13-1991 indicators, the researchers concluded 
    that the incidence of STS's was as good as the ANSI test criteria as an 
    early indicator of the effectiveness of an HCP from the first two 
    audiograms.
        NIOSH (1995) recommended a simple method of determining the 
    effectiveness of an HCP. According to NIOSH, if less than 5% (1 out of 
    20) of the noise-exposed workers enrolled in an HCP incur an 
    occupationally-induced STS, the HCP is deemed effective. According to 
    NIOSH, this method should be used to continually monitor the results of 
    audiometric testing to indicate the effectiveness of the HCP before 
    many individuals incur permanent shifts in hearing acuity.
        While MSHA recognizes that the ADBA technique may be promising, the 
    Agency is concerned that it may not be practical for the majority of 
    mine operators. The ADBA technique may not be applied reliably to 
    populations of fewer than 30 individuals and about 90% of the 15,000 
    mines under MSHA's jurisdiction employ less than 30 miners. Even if 
    every miner was placed in an HCP, regardless of noise exposure, less 
    than 10% of the mines could consider using the ANSI draft ADBA 
    procedures to evaluate their HCP. ADBA analysis also may not be 
    appropriate if the workforce being analyzed is not stable, exhibiting a 
    high turnover rate. MSHA has determined that this may be the case for 
    many small mines which operate seasonally, are portable, or change 
    geographic locations. Currently, the annual turnover rate in mining 
    ranges from 2% in large coal mines to 11% in small metal and nonmetal 
    mines.
        In addition, ADBA requires several years of data before the 
    analysis can be conducted. Consequently, ADBA cannot be used to 
    immediately determine the effectiveness of an HCP unless audiograms 
    were collected prior to the effective date of the rule.
        Finally, existing procedures for conducting ADBA call for the use 
    of audiograms taken without observing a quiet period. Both OSHA's 
    existing standard and this proposal require a 14-hour quiet period 
    before conducting a baseline audiogram. These standards, however, do 
    not address a quiet period for annual audiograms, leaving the choice to 
    the employer or the mine operator. Consequently, where a quiet period 
    is used, those audiograms could not be used in conducting ADBA.
        MSHA also is concerned that the statistical methods employed by 
    ADBA require the use of a computer, which many small mine operators may 
    not have. Consequently, many mine operators may need to employ outside 
    consultants to conduct this analysis. Because the ADBA techniques are 
    relatively new, a sufficient number of consultants, who fully 
    understand and can utilize this analytical technique, may not be 
    available. Despite the problems with ADBA analysis for the mining 
    industry, MSHA recognizes that it may be a valuable tool for 
    identifying and correcting problems in an HCP before an STS occurs. 
    MSHA does not wish to discourage mine operators from using this 
    technique.
        The analysis of an HCP's effectiveness can be as simple as 
    comparing a current audiogram with prior audiograms. This simple 
    approach, however, can be extremely time consuming and may not identify 
    trends among miners.
        Further, international communities and selected branches of the 
    U.S. armed services require the effectiveness of the HCP's to be 
    evaluated even though they do not include specific methods for the 
    evaluation.
        MSHA, however, is not specifying a methodology to determine the 
    effectiveness of an HCP for several reasons. First, there is not a 
    consensus among researchers and commenters as to a method even though a 
    draft ANSI standard (ADBA) has been published on this issue. Secondly, 
    the techniques for evaluating the effectiveness of an HCP that have 
    been developed are not appropriate to an HCP with few participants. 
    MSHA estimates that most HCP's in the mining industry would not have a 
    sufficient number of participants to be tested. Further, MSHA contends 
    that there are few consultants and fewer mine operators with the 
    expertise to evaluate the effectiveness of an HCP.
        MSHA requests specific suggestions on practical methods which could 
    be used in the mining industry, particularly among small mine
    
    [[Page 66407]]
    
    operators, to evaluate the effectiveness of HCP's. MSHA also requests 
    comments on NIOSH's above stated recommendations.
    Temporary or Seasonal Miners
        The proposal would not provide any exemption from the requirements 
    to provide audiometric examinations for temporary or seasonal miners.
        OSHA has no such explicit requirement. Moreover to create such an 
    exemption would mean that workers who change jobs--within a single 
    industry, or between industries--might end up never having a check on 
    hearing loss even if working in very noisy conditions.
        The proposal does include certain provisions that might in practice 
    exclude some miners from examinations otherwise required. A mine 
    operator has up to 6 months to conduct a baseline audiogram--up to 12 
    months if a mobile van is used. Thus in practice, the operator's 
    obligation to provide examinations does not extend to those miners who 
    leave employment before this time and who do not subsequently return to 
    work for the same operator. Many summer employees might fall into this 
    category.
        MSHA solicits further comment on this issue.
    Permissible Exposure Level (PEL)
        Proposed Sec. 62.120(c) provides as follows:
    
        No miner shall be exposed to noise in excess of a TWA8 of 
    90 dBA (PEL) during any workshift, or equivalently a dose of 100%.
        (1) If a miner's noise exposure exceeds the PEL, the operator 
    shall, in addition to taking the actions required under paragraph 
    (b) of this section, use all feasible engineering and administrative 
    controls to reduce the miner's noise exposure to the PEL. When 
    administrative controls are used to reduce a miner's exposure, the 
    operator shall post these procedures on the mine bulletin board and 
    provide a copy to affected miners.
        (2) If a miner's noise exposure exceeds the PEL despite the use 
    of the controls required by paragraph (c)(1) of this section, the 
    operator shall take the actions required by this paragraph for that 
    miner.
        (i) The operator shall use the controls required by paragraph 
    (c)(1) of this section to reduce the miner's noise exposure to as 
    low a level as is feasible.
        (ii) The operator shall ensure that a miner whose exposure 
    exceeds the PEL takes the hearing examinations offered through 
    enrollment in the hearing conservation program.
        (iii) The operator shall provide hearing protection to a miner 
    whose exposure exceeds the PEL and shall ensure the use thereof. The 
    hearing protection shall be provided and used in accordance with the 
    requirements of Sec. 62.125.
    
        This paragraph would establish the permissible exposure limit (PEL) 
    to noise for a miner as a TWA8 of 90 dBA during any workshift. 
    (This is also referred to as a dose measurement of 100%; the action 
    level TWA8 of 85 dBA is half this dose of noise.)
        The PEL is a time-weighted average sound level to which a miner may 
    be exposed that establishes the maximum dose of noise permitted. Under 
    the proposal, this is established as a TWA8 of 90 dBA--the same as 
    at present. TWA8 refers to a time-weighted-8-hour average, a term 
    defined in proposed Sec. 62.110. The exposure needed to reach the PEL 
    varies by sound level and time. For example, the PEL would be reached 
    as a result of exposure to a sound level of 90 dBA for 8 hours, but 
    also reached by exposure to a sound level of 95 dBA for only 4 hours or 
    92 dBA for 6.1 hours.
        The Agency considered proposing a different PEL. As noted in part 
    II of the preamble, MSHA has concluded that there is a significant risk 
    of material impairment from noise exposures at or above a TWA8 of 
    85 dBA. MSHA considered setting the PEL at this level, but as discussed 
    in part IV of this preamble believes that this may not be feasible at 
    this time for the mining industry. Accordingly, the Agency is proposing 
    to keep the PEL at a TWA8 of 90 dBA--the level in effect for the 
    mining industry and under OSHA. The PEL is a dose twice that which 
    would be received at the level at which there is a significant risk of 
    material impairment.
        While the PEL would not change, the actions required if noise 
    exposure exceeds the PEL would in many cases be different from those 
    currently required.
        Under the proposal, a hierarchy of controls is established for all 
    mines. Mine operators must first utilize all feasible engineering and 
    administrative controls to reduce sound levels to the PEL. This 
    approach is more consistent with MSHA's existing noise standards for 
    metal and nonmetal mines than for coal mines. Under the current metal 
    and nonmetal regulations, mine operators have to utilize either 
    engineering or administrative controls to reduce noise to the PEL or as 
    close thereto as feasible. In the coal industry, MSHA inspectors do not 
    cite for noise without first deducting the attenuating value of hearing 
    protectors being worn by the miners subjected to excessive exposures of 
    noise. In practice, this means personal protective equipment is in most 
    cases accepted as a substitute for engineering and administrative 
    controls.
        As under the present standards, the proposal would require a mine 
    operator to use only such engineering controls as are technologically 
    feasible, and to use only such engineering and administrative controls 
    as are economically feasible for that mine operator.
        Moreover, the proposed rule spells out explicit requirements that 
    will supplement these controls in those cases in which the Agency 
    concurs with a mine operator that the use of all feasible engineering 
    and administrative controls cannot reduce noise to the PEL. All sectors 
    of the mining industry will, in such cases, have to provide all miners 
    exposed above the PEL with a properly fitting hearing protector, ensure 
    the miners use those protectors, and ensure that miners take their 
    annual hearing examinations.
    Existing Standards
        MSHA's existing metal and nonmetal noise standards require the use 
    of feasible engineering and administrative controls when a miner's 
    noise exposure exceeds the PEL. Hearing protectors are also required if 
    the exposure cannot be reduced to within the PEL. The existing metal 
    and nonmetal standards do not, however, require the mine operator to 
    post the procedures for any administrative controls used, to conduct 
    specific training, or to enroll miners in hearing conservation 
    programs.
        MSHA's existing noise practices for coal mines are significantly 
    different from those for metal and nonmetal mines. The difference stems 
    from the circumstances under which the Agency is authorized to issue 
    citations. In metal and nonmetal mines, a citation is issued based 
    exclusively on the exposure measurement--when MSHA measures an exposure 
    at a TWA8 of 90 dBA. But in coal mines, a citation is not issued 
    in such a case if the miners are wearing hearing protection judged to 
    be appropriate. The appropriateness is based on the EPA noise reduction 
    rating minus 7 dB; in practice, most hearing protectors have ratings 
    which meet this official test for many coal mine exposures. 
    Accordingly, citations are seldom issued.
        When coal mine operators do receive a citation for a miner's noise 
    exposure exceeding the PEL, they are required to promptly institute 
    administrative and/or engineering controls to assure compliance. 
    Additionally, within 60 days of receiving a citation, coal mine 
    operators are required to submit to MSHA a plan for the administration 
    of a continuing, effective hearing conservation program, including 
    provisions for--
        (1) Reducing environmental noise levels;
    
    [[Page 66408]]
    
        (2) Making personal ear protective devices available to miners;
        (3) Conducting pre-placement and periodic audiograms; and,
        (4) Instituting engineering and administrative controls to ensure 
    compliance with the standard (underground only).
        With regard to MSHA's existing noise standard, the Federal Mine 
    Safety and Health Review Commission (Commission) has addressed the 
    issue of what MSHA must consider, when determining what is a feasible 
    noise control for enforcement purposes, at a particular mine. According 
    to the Commission, a control is considered feasible when: (1) the 
    control reduces exposure, (2) the control is economically achievable, 
    and (3) the control is technologically achievable. See Secretary of 
    Labor v. Callanan Industries, Inc., 5 FMSHRC 1900 (1983), and Secretary 
    of Labor v. A. H. Smith, 6 FMSHRC 199 (1984).
        In determining technological feasibility of a regulation, the 
    Commission has ruled that a control is deemed achievable if through 
    reasonable application of existing products, devices, or work methods 
    with human skills and abilities, a workable engineering control can be 
    applied to the noise source. The control does not have to be ``off-the-
    shelf''; but, it must have a realistic basis in present technical 
    capabilities.
        In determining economic feasibility, the Commission has ruled that 
    MSHA must assess whether the costs of the control are disproportionate 
    to the ``expected benefits,'' and whether the costs are so great that 
    it is irrational to require its use to achieve those results. The 
    Commission has expressly stated that cost-benefit analysis is 
    unnecessary in order to determine whether a noise control is required. 
    According to the Commission, an engineering control may be feasible 
    even though it fails to reduce exposure to permissible levels contained 
    in the standard, as long as there is a significant reduction in 
    exposure. Todilto Exploration and Development Corporation v. Secretary 
    of Labor, 5 FMSHRC 1894 (1983). No guidance has been provided by the 
    Commission as to what level of reduction is considered significant. 
    However, the Commission has accepted the Agency's determination that a 
    3 dBA reduction is significant.
        MSHA has interpreted the ``expected benefits'' to be the amount of 
    noise reduction achievable by the control. MSHA generally considers a 
    reduction of 3 dBA or more to be a significant reduction of the sound 
    level because it represents at least a 50% reduction in sound energy. 
    Consequently, a control that achieves relatively little noise reduction 
    at a high cost could be viewed as not meeting the Commission's test of 
    economic feasibility.
        Consistent with the case law, MSHA considers three factors in 
    determining whether engineering controls are feasible at a particular 
    mine: first, the nature and extent of the overexposure; second, the 
    demonstrated effectiveness of available technology; and third, whether 
    the committed resources are wholly out of proportion to the expected 
    results. Before a violation of these requirements of the standard could 
    be found, MSHA would have to determine that a worker has been 
    overexposed; that administrative or engineering controls are feasible; 
    and that the mine operator failed to install or maintain such controls. 
    (See also the discussion of enforcement policy in the last of the 
    Questions and Answers in part I.)
        OSHA's PEL is a TWA8 of 90 dBA, computed using a 90 dBA 
    threshold. The standard requires the use of feasible engineering or 
    administrative controls when a citation for exceeding the PEL is 
    issued. Under OSHA policy (CPL 2.45A CH-12), however, if an effective 
    HCP is in place, no STS has been detected, and adequate hearing 
    protectors are utilized, no citation will be issued for noise exposures 
    up to a TWA8 of 100 dBA if the costs to implement the HCP are less 
    than those of engineering or administrative controls. In determining 
    the appropriateness of hearing protection for this purpose, OSHA 
    reduces the EPA rating by 7; but it then further reduces effectiveness 
    by halving the result of that calculation. (A more detailed discussion 
    of hearing protector derating approaches can be found in the section on 
    Hearing Protector Effectiveness, part of the discussion of proposed 
    Sec. 62.125.)
    Comments and Studies on PEL
        Several commenters to MSHA's ANPRM recommended a PEL of 85 dBA. One 
    of these stated the following:
    
        The current PEL provides inadequate protection for miner's 
    hearing. The 90 dB(A) PEL is excessive and permits noise exposure 
    that will result in significant hearing loss among exposed miners. 
    Specifically, 21 to 29% of workers exposed to 90 dBA for 40 years 
    will suffer material impairment of hearing. Material impairment of 
    hearing, defined by OSHA in this case, is 25 dBA or more loss for 
    the frequencies 1, 2, and 3 kHz. Based on this risk of damage, OSHA 
    adopted a hearing conservation program that is required when noise 
    exposure reaches 85 dBA TWA.
    
        Another of these commenters recommended a PEL of 85 dBA with an 80 
    dBA action level. This commenter stated that:
    
        Both OSHA and the National Institute for Occupational Safety and 
    Health (NIOSH) have recommended a PEL of 85 dBA. This level seems to 
    be an appropriate PEL for mining as well, since the numbers of 
    miners with hearing loss continues to be a problem. Obviously a more 
    conservative approach would be to utilize 80 dBA as the action level 
    to trigger the implementation provisions of an HCP. Although more 
    costly, the benefits for prevention of NIHL would certainly be 
    substantial.
    
        Many commenters on this issue, however, believe that MSHA's current 
    PEL of 90 dBA should be retained and that it is adequate to protect 
    miners. One commenter referenced Bartsch (see Related Studies in the 
    III. Nature of the Hazard section of this preamble) as supporting 
    evidence for retaining the PEL of 90 dBA. Three commenters cited lack 
    of compensable noise-induced hearing loss (NIHL) cases among miners in 
    their geographical area as a positive indication that the current PEL 
    is adequate and they questioned the benefit of reducing the PEL to 85 
    dBA. These commenters also stated that about 20% of the miners in their 
    area were exposed to average sound levels above 85 dBA, but under 90 
    dBA.
        In addition to the comments received in response to its ANPRM, MSHA 
    also reviewed numerous studies and standards relating to the 
    establishment of a PEL.
        The Physical Agents Threshold Limit Value Committee of American 
    Conference of Governmental Industrial Hygienists (ACGIH) (1993) has 
    adopted a Threshold Limit Value (TLV) of 85 dBA Leq,8. The 
    committee believed that there was a clear consensus that an 85 dBA TLV 
    was valid and needed to protect the hearing acuity of workers at the 
    higher audiometric frequencies of 3000 and 4000 Hz.
        Stekelenburg (1982) suggests that 80 dBA be the acceptable level 
    for noise exposure over a 40 year work history. Moreover, the 
    researcher suggests that extra precautions are necessary for sensitive 
    individuals and that these people need to be identified during the 
    first five years of exposure to noise.
        Embleton (1994) summarized the occupational noise regulations 
    (pertaining to: PEL, exchange rate, and the upper limit for noise 
    exposure) from 17 countries and selected branches of the U.S. armed 
    services. His summary table (absent the recommendations in his report) 
    is reproduced below as Table III-4.
    
    [[Page 66409]]
    
    
    
                                           Table III-4.--Some Features of Legislation Tabulated for Various Countries*                                      
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              Limit for                                                                     
                                    LAeq 8-hour exposure                   engineering or    Limit for monitoring                                           
        Country (jurisdiction)              rate           Exchange rate   administrative          hearing                Upper limit for sound level       
                                                                              controls                                                                      
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    Australia (varies by state)..  85 dB................  3 dB..........  85 dBA..........  85 dBA...............  140 dB lin, peak.                        
    Brazil.......................  85 dB................  5 dB..........  90 dBA, no        85 dBA...............  130 dB peak.                             
                                                                           exposure >115                                                                    
                                                                           dBA if no                                                                        
                                                                           protection.                                                                      
    Canada:                                                                                                                                                 
        (Federal)................  87 dB................  3 dB..........  87 dB...........  84 dBA...............  140 dB peak.                             
        (ON, QU, NB).............  90 dB................  5 dB..........  90 dBA..........  85 dBA (a)...........                                           
        (AB, NS, NF).............  85 dB................  5 dB..........  85 dBA..........                                                                  
        (BC).....................  90 dB................  3 dB..........  90 dBA..........                                                                  
    China........................  70-90................  3 dB..........  ................  .....................  115 dBA.                                 
    Finland......................  85 dB................  3 dB..........  85 dB...........                                                                  
    France (b)...................  85 dB................  3 dB..........  90 dBA or 140 dB  85 dBA...............  135 dB peak.                             
                                                                           peak.                                                                            
    Germany (b), (c).............  85 dB................  3 dB..........  90 dBA..........  85 dBA...............  140 dB peak.                             
    Hungary......................  85 dB................  3 dB..........  90 dBA..........  .....................  125 dBA or 140 dB peak.                  
    Israel.......................  85 dB 5 dB...........  ..............  ................  115 dBA or 140 dB                                               
                                                                                             peak..                                                         
    Italy........................  85 dB................  3 dB..........  90 dB...........  85 dB................  140 dB peak.                             
    Netherlands..................  80 dB................  3 dB..........  85 dB...........  140 dB peak..........                                           
    New Zealand..................  85 dB................  3 dB..........  85 dBA +3 dB      115 dBA slow or 140                                             
                                                                           exchange rate.    dB peak..                                                      
    Norway.......................  85 dB................  3 dB..........  ................  80 dBA...............  110 dBA.                                 
    Spain........................  85 dB................  3 dB..........  90 dBA..........  80 dBA...............  140 dB peak.                             
    Sweden.......................  85 dB................  3 dB..........  90 dBA..........  80 dBA...............  115 dBA or 140 dBC.                      
    United Kingdom...............  85 dB................  3 dB..........  90 dBA..........  85 dBA...............  140 dB peak.                             
    USA (d)......................  90 dB (TWA8).........  5 dB..........  90 dBA but no     85 dBA...............  115 dBA or 140 dB peak.                  
                                                                           exposure >115                                                                    
                                                                           dBA.                                                                             
    USA Army and Air Force)......  84 dB................  3 dB..........  ................  85 dBA...............  140 dB peak.                             
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    *Embleton (1994).                                                                                                                                       
    Information for countries not represented by Member Societies participating in the Working Party is taken from Ref. 15.                                 
    (a) A more complex situation is simplified to fit this tabulation.                                                                                      
    (b) These countries require the noise declaration of machinery, the use of the quietest machinery where reasonably possible, and reduced reflection of  
      noise in the building, regardless of sound or exposure levels.                                                                                        
    (c) The noise exposure consists of LAeq and adjustments for tonal character and impulsiveness.                                                          
    (d) TWA is Time Weighted Average. The regulations in the U.S. are unusually complex because different thresholds are used to compute levels to initiate 
      hearing programs (85 dBA), noise exposure monitoring (80 dBA), and noise reduction measures (90 dBA), each using a 5-dB exchange rate.                
    
        Embleton included recommendations based upon current practice taken 
    from the various jurisdictions:
    
    ----------------------------------------------------------------------------------------------------------------
                                                  Limit for engineering                                             
       LAeq 8-hour ex-         Exchange rate        or administrative     Limit for monitoring     Upper limit for  
         posure rate                                     controls               hearing              sound level    
    ----------------------------------------------------------------------------------------------------------------
    85 dBA...............  3 dBA................  Use quietest machines  On hiring and at       140 dB peak.        
                                                   and room absorption    intervals thereafter.                     
                                                   in workplaces.                                                   
    ----------------------------------------------------------------------------------------------------------------
    
        He stated that:
    
        The primary goal of this report and its recommendations is to 
    reduce the risk of long term hearing damage and expose people to a 
    practical minimum. . . . Each feature recommended had been 
    considered to be practicable by at least one national jurisdiction 
    and there may be some experience of its usefulness. Much current 
    legislation was enacted several years ago, before the more recent 
    scientific evidence was available and before it was integrated into 
    current understanding of this complex scientific topic.
    
        The U.S. armed services and possibly some international communities 
    do not go through a public rulemaking process in establishing their 
    respective noise regulations. Nevertheless, MSHA has included these 
    sources to show that a consensus exists on noise legislation. Table 
    III-5 lists information similar to that included in Table III-4 for 
    several additional entities. Furthermore, there was a discrepancy found 
    in Table III-4 as per the information provided for the U.S. armed 
    services. The corrected information is included in Table III-5 
    (compiled by MSHA).
    
                                            Table III-5.--Features of Noise Exposure Criteria for Additional Entities                                       
    --------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Limit for                                                            
                                            LAeq 8- hour                            exgineering or          Limit for                                       
          Country or jurisdiction          exposure rate        Exchange rate       administrative      monitoring hearing     Upper limit for sound level  
                                                                                       controls                                                             
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    American Conference of              85 dBA.............  3-dB..............  ....................  85 dBA.............  140 dBC peak.                   
     Governmental Industrial                                                                                                                                
     Hygienists (ACGIH).                                                                                                                                    
    
    [[Page 66410]]
    
                                                                                                                                                            
    European Economic Community (EEC).  85 dBA.............  3-dB..............  90 dBA..............  85 dBA.............  140 dB peak.                    
    South Africa......................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  115 dBA or 150 dB.              
    U.S. Air Force....................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  115 dBA or 140 dB.              
    U.S. Army.........................  85 dBA.............  3-dB..............  85 dBA..............  85 dBA.............  140 dB.                         
    U.S. Navy.........................  84 dBA.............  4-dB..............  84 dBA..............  84 dBA.............  140 dB.                         
    State of Western Australia........  90 dBA.............  3-dB..............  90 dBA..............  ...................  140 dB.                         
    --------------------------------------------------------------------------------------------------------------------------------------------------------
    
        Because the information contained in Tables III-4 and III-5 does 
    not include every jurisdiction, MSHA solicits additional information on 
    features of noise legislation for comparison purposes.
    Hierarchy of Controls
        The proposal would require mine operators to use all feasible 
    engineering or administrative controls or a combination of these 
    controls to reduce a miner's daily noise exposure to the PEL. If these 
    controls do not reduce the exposure to the PEL, then they shall be used 
    to reduce the exposure as low as feasible. The proposal does not place 
    preference on the use of engineering controls over administrative 
    controls; but all feasible controls of both types must be implemented 
    to reduce noise exposure to the PEL or as close thereto as is possible 
    when all feasible controls are utilized.
        MSHA's proposed requirements for either feasible engineering or 
    administrative controls or a combination of these controls are closer 
    to MSHA's existing noise standards for metal and nonmetal mines than to 
    the standards for coal mines.
        In metal and nonmetal mines, engineering or administrative controls 
    are required to the extent feasible when exposures exceed a TWA8 
    of 90 dBA. Current metal and nonmetal enforcement requirements equate 
    engineering and administrative controls and do not accept hearing 
    protectors in lieu of such controls. Mine operators in these 
    industries, which have a significant percentage of small employers, 
    generally opt to use engineering controls over administrative controls, 
    citing practical difficulties with the implementation of the latter. 
    Administrative controls reduce exposure by limiting the amount of time 
    that a miner is exposed to noise, through such actions as rotation of 
    miners to areas having lower sound levels, rescheduling of tasks, and 
    modifying work activities.
        The hierarchy of noise control for coal mines is significantly 
    different. In determining whether the mine operator is in violation of 
    the PEL, MSHA deducts from noise exposure measurements the corrected 
    attenuation of hearing protectors being worn by the miners. Given 
    normal conditions in these mines, when hearing protectors are being 
    worn, no citation is issued.
        OSHA's standard requires the use of feasible engineering or 
    administrative controls. As discussed above, however, current OSHA 
    policy allows employers to rely on a combination of other controls--
    enrollment in an HCP, no STS, and adequate hearing protectors (measured 
    in accordance with specifications adjusted for the purpose of the 
    policy)--up to a noise exposure of 100 dBA, provided that the cost is 
    less than that of the engineering and/or administrative controls.
        A number of commenters responding to MSHA's ANPRM, specifically 
    supported the primacy of engineering controls. One commenter supported 
    the primacy of engineering controls citing anecdotal evidence that 
    miners resist wearing hearing protectors. Another commenter stated that 
    engineering controls for mining are far more available than commonly 
    thought.
        Several commenters stated that administrative controls can be 
    effective but are often impractical. One commenter stated that 
    administrative controls are effective but are of limited use at small 
    operations because there are not enough people to rotate through the 
    various jobs. Another commenter stated that although the use of 
    administrative controls may lower the exposure of an individual miner 
    such controls have the disadvantage of increasing overall exposure to a 
    larger population. A third commenter stated that administrative 
    controls should be the least preferred control method.
        A significant number of commenters specifically requested that MSHA 
    allow the use of hearing protectors in lieu of engineering or 
    administrative controls, as long as the hearing protector provided 
    adequate attenuation. These commenters believed that hearing protectors 
    were equally as effective as engineering and administrative controls.
        Many commenters recommended that MSHA allow the mine operator a 
    choice or combination of controls, including the use of an HCP. Several 
    commenters stated the following:
    
        There is no logical reason to handcuff operators by limiting 
    flexibility and freedom of choice in selecting the most appropriate 
    method of noise protection for the particular application; 
    providing, of course, the method is effective.
        For some reason HPD's (hearing protection devices) have been 
    regulated to be a third class behind administrative, and engineering 
    controls. It is our experience the HPD's provide more effective, 
    less costly, and more reliable protection than engineering or 
    administrative controls in many circumstances. The employee 
    acceptance is also good to excellent. Therefore the discrimination 
    against HPD's should be removed in any future regulations.
    
        Dear (1987) contends that employers can manage the risk of hearing 
    impairment by encouraging all employees to participate in the HCP and 
    that an HCP can be as effective, in many cases, as the use of other, 
    more costly controls. He believes that some workers are better served 
    by wearing hearing protectors than reducing the noise via engineering 
    controls to the PEL. He contends that removing the hearing protectors 
    when the sound levels are reduced to 90 dBA [by engineering controls] 
    would expose workers to at least 90 dBA; whereas, use of hearing 
    protectors would reduce exposures much lower. Dear cites studies 
    conducted by DuPont on their employees to show the effectiveness of 
    hearing protectors. Employees in the DuPont HCP, which includes hearing 
    protectors and begins at approximately 90 dBA, had not developed 
    hearing impairment during the study period.
        Pell and Dear (1988) believe that employees exposed above 90 dBA 
    are better protected by using appropriate hearing protectors, rather 
    than implementing engineering controls to
    
    [[Page 66411]]
    
    reduce the noise to 89 dBA or even 84 dBA.
        Berger (1983) states the following regarding engineering controls 
    versus hearing protectors:
    
        When one compares engineering noise controls to HPDs [hearing 
    protectors], it must be remembered that the same types of problems 
    which afflict HPD performance in the RW [real world], will tend to 
    reduce the effectiveness of noise control measures as well. For 
    example, one of the most commonly used treatments is an enclosure. 
    If it is not well fitted, or left partially ajar, or circumvented by 
    an inconvenienced employee, or its gaskets and seals age, 
    deteriorate, or break in any way, then its performance will be 
    degraded in a manner similar to that which has been observed for 
    poorly fitted and misused HPDs. When noise control is achieved by 
    improved adjustments and lubrication, there must be a trained and 
    dedicated employee to monitor the maintenance schedule, just as 
    employees must care for and maintain their HPDs. In fact most 
    engineering noise control procedures, except for some source noise 
    control accomplished through equipment redesign, require maintenance 
    and periodic adjustment or replacement to continue functioning 
    properly. And except for enclosures, noise reductions of 10 dB or 
    more are often difficult to achieve and maintain. Thus HPDs remain 
    one of the most important protective methods for a hearing 
    conservationist to consider, and can provide an effective adjunct to 
    engineering noise controls in the majority of industrial noise 
    environments.
    
        Nilsson et al. (1977) studied hearing loss in shipbuilding workers. 
    The workers were divided into two groups. In the first group, the 
    workers were exposed to 94 dBA with 95% of the workers using hearing 
    protectors. In the second group, the workers were exposed to 88 dBA and 
    90% of them wore hearing protectors. Both groups were subjected to 
    impulse noise up to 135 dB. Despite the fact that the vast majority of 
    the workers in both groups wore hearing protectors, cases of noise-
    induced hearing loss (NIHL) were common. The mean pure tone audiograms 
    showed the typical noise dip at 4000 Hz. For increased exposure 
    durations, the amount of NIHL increased. Workers exposed to 94 dBA 
    exhibited more hearing loss than those exposed to 88 dBA. Nilsson 
    concluded that 58.1% of all of the workers had some degree of hearing 
    impairment, and only 1.8% was caused by factors other than noise after 
    excluding hearing loss due to heredity, skull injury, or ear disease. 
    According to Nilsson et al., the hearing protectors should have 
    attenuated the noise by at least 13 dBA. This study concluded that 
    reliance on hearing protectors alone is not sufficient to protect the 
    hearing acuity of the workers.
        NIOSH's position regarding the hierarchy of controls is stated in 
    their December 16, 1994 comments to MSHA (NIOSH 1994). According to 
    NIOSH there are three elements of an effective hierarchy of controls. 
    They are--
        1. Prevent or contain hazardous workplace emissions at their 
    source;
        2. Remove the emissions from the pathway between the source and the 
    worker; and
        3. Control the exposure of the worker with barriers between the 
    worker and the hazardous work environment.
        NIOSH further states that the essential characteristics of specific 
    control solutions are--
        1. The levels of protection afforded workers must be reliable, 
    consistent, and adequate;
        2. The efficacy of the protection for each individual worker must 
    be determinable during use throughout the lifespan of the system;
        3. The solution must minimize dependence on human intervention for 
    its efficacy so as to increase its reliability; and
        4. The solution must consider all routes of entry into worker's 
    bodies and should not exacerbate existing health or safety problems or 
    create additional problems of its own.
        NIOSH (1988), in its publication entitled ``Proposed National 
    Strategy for the Prevention of Noise-Induced Hearing Loss'' 
    (Publication No. 89-135), encouraged OSHA to rescind its policy of 
    accepting HCP's in lieu of either feasible engineering and/or 
    administrative controls and states:
    
        It is extremely foolhardy to regard hearing protection as a 
    preferred way to limit noise exposures because most employees obtain 
    only half the sound attenuation possible from hearing protectors. 
    Even with training, some workers fail to obtain maximum benefit from 
    these protectors because they have difficulty adjusting them 
    properly, or they refuse to wear them because they fear such devices 
    will impair their ability to perform their jobs properly or hear 
    warning signals. If, however, noise is reduced by engineering and/or 
    administrative controls, the limitations of hearing protectors are 
    of less concern.
    
        In the report, ``Preventing Illness and Injury in the Workplace,'' 
    the Office of Technology Assessment (1985) found that health 
    professionals rank engineering controls as the priority means of 
    controlling exposure, followed by administrative controls, with 
    personal protective equipment as a last resort.
        The National Hearing Conservation Association (NHCA) in a letter 
    from their President, Susan Cooper Megerson (1994), to Joseph Dear, 
    Assistant Secretary of Labor for Occupational Safety and Health, urged 
    OSHA to rescind its policy of accepting an HCP in lieu of engineering 
    noise controls for exposures up to 100 dBA. NHCA contends that feasible 
    engineering controls should be the preferred method of controlling the 
    noise. Further, NHCA states that ``Most hearing protectors, as they are 
    worn in the field, do not provide sufficient attenuation to bring 
    workers' exposures from 100 dB(A) to safe noise levels.''
        Suter (1994) in a letter to Sue Andrei of OSHA's Policy Directorate 
    urged OSHA to rescind its policy of accepting an HCP in lieu of 
    engineering and/or administrative controls for exposures up to 100 dBA. 
    Suter contends that most HCPs are ineffective due to hearing protectors 
    providing only a fraction of their laboratory attenuation. Further, 
    Suter urges OSHA to re-emphasize engineering noise controls.
        MSHA understands that the two letters to OSHA were sent in response 
    to an OSHA request for comment on how to design a priority scheme for 
    OSHA standards. No responses were issued, and the priority scheme is 
    still pending. MSHA has also reviewed a recent letter to the EPA from 
    the American Industrial Hygiene Association questioning the rating 
    system used to label hearing protectors with attenuation values; this 
    is discussed above in the section on Hearing protector effectiveness 
    (in connection with proposed 62.125).
        In summary, commenters and researchers on this issue were divided 
    as to whether engineering/administrative controls should have primacy 
    over the use of hearing protectors or an HCP. Most of the international 
    community, U.S. armed services, and NIOSH, however, discourage the use 
    of hearing protectors and an HCP as the primary means of control and 
    accept their use only when engineering and administrative controls 
    failed to achieve a significant reduction in the worker's exposure.
        Administrative controls reduce exposure by limiting the amount of 
    time that a miner is exposed to noise, through such actions as rotation 
    of miners to areas having lower sound levels, rescheduling of tasks, 
    and modifying work activities. Many mine operators have demonstrated 
    that administrative controls can be as effective and less costly than 
    the installation of engineering controls. However, the use of 
    administrative controls may be limited by labor/management agreements, 
    limitations on the number of qualified miners capable of handling a 
    specific task, or difficulty in ensuring that miners adhere to the
    
    [[Page 66412]]
    
    administrative controls. Additionally, administrative controls have the 
    potential draw back of exposing multiple workers to high sound levels 
    for designated time periods. Because the effectiveness of 
    administrative controls is based on adherence to these strict time 
    periods, mine operators may find it difficult to verify compliance with 
    the administrative procedures.
        Although there are some disadvantages to using administrative 
    controls, the Agency has determined that in certain circumstances they 
    can be as effective as engineering controls. MSHA, therefore, believes 
    that the mine operator should have the option to choose which method of 
    control to use--provided that all feasible controls must be utilized if 
    needed to reduce sound levels to or below the PEL. This would give mine 
    operators maximum flexibility when considering the intricacies of their 
    operation in complying with the regulation. Administrative controls, 
    utilized properly, spread the risk over a larger population although at 
    a lower risk to each individual.
        A related type of control would be the transfer of miners to other 
    assignments. The Mine Safety and Health Act provides for the Agency to 
    prescribe such an approach in certain cases. MSHA considered proposals 
    to do so in cases in which an STS is detected. Discussion of this topic 
    is covered by the section of the preamble that reviews proposed 
    Sec. 62.180.
        Based upon its review of the available evidence, MSHA concludes 
    that a reduction of a miner's risk of material impairment due to 
    occupational NIHL noise can best be achieved through the use of all 
    feasible engineering or administrative controls or a combination 
    thereof. The use of engineering controls inherently provides the most 
    consistent and reliable protection because such controls do not depend 
    upon individual human performance or intervention to function. MSHA's 
    proposal would, however, allow mine operators to use either engineering 
    or administrative controls. This would provide the mine operator with 
    the flexibility to select the most appropriate control for the 
    situation. These methods would be given clear primacy over personal 
    protective controls. While MSHA is aware that NIOSH is seeking to 
    develop an approach that would more accurately derate hearing 
    protectors in actual workplace use, the prospects for this remain 
    uncertain; moreover, the issues associated with the consistency and 
    reliability of personal protective equipment use would remain.
    Engineering Noise Controls for Mining Equipment
        Engineering noise controls reduce exposure by modifying the noise 
    source, noise path or the receiver's environment thereby decreasing the 
    miner's exposure to harmful sound levels. Examples of these three types 
    of engineering controls are exhaust mufflers, barriers, and 
    environmental cabs, respectively. Exposures may also be controlled by 
    substituting quieter mining equipment. For example, a diamond wire saw 
    can be substituted for a conventional hand-held channel burner in the 
    dimension stone industry.
        MSHA has listed feasible engineering controls for the major 
    classifications of equipment used in metal and nonmetal mines in its 
    Program Policy Manual, Volume IV. The engineering controls referenced 
    in this manual have been evaluated by MSHA Technical Support and proven 
    feasible and effective in the mining industry. This document is 
    currently used by MSHA inspectors and others to assist in determining 
    if engineering controls are feasible. Following are some examples of 
    the feasible controls covered in that manual.
        1. Acoustically treated cabs. For mining equipment such as haul 
    trucks, front-end-loaders, bulldozers, track drills, and underground 
    jumbo drills, acoustically treated cabs are among the most effective 
    noise controls. Such cabs are widely available, from the original 
    equipment manufacturer and the manufacturers of retrofit cabs, for 
    machines manufactured within the past 20 years. The noise reduction of 
    factory installed acoustically treated cabs is generally more effective 
    than that of retrofit cabs. According to some manufacturers, sound 
    levels at the mine operator's position inside factory cabs are often 
    below 90 dBA and in some cases below 85 dBA.
        Occasionally, underground mining conditions are such that full-
    sized surface haulage equipment can be used. Where this is possible, 
    such equipment can be equipped with a cab as described above. 
    Additionally, some manufacturers offer cabs for lower profile 
    underground mining equipment such as scoop-trams, shuttle cars, and 
    haul trucks. The use of cabs on such underground mobile haulage 
    equipment generally is feasible provided it does not create a safety 
    hazard due to impaired visibility.
        The former USBOM has published two how-to manuals entitled 
    ``Bulldozer Noise Controls'' (1980), and ``Front-End Loader Noise 
    Controls'' (1981) that describe in great detail how to install a 
    retrofit cab and install acoustical materials.
        2. Barrier shields. For some equipment, generally over 20 years 
    old, an environmental cab may not be available from the original 
    equipment manufacturer or from manufacturers of retrofit cabs. In such 
    cases, a partial barrier with selective placement of acoustical 
    material can generally be installed at nominal cost to block the noise 
    reaching the equipment operator. These techniques are also demonstrated 
    in ``Bulldozer Noise Controls'' (1980).
        Barrier shields and partial enclosures can also be used on track 
    drills where full cabs are not feasible. Such shields and enclosures 
    can be either free standing or attached to the drill. Typically, 
    however, they are not as effective as cabs and usually do not reduce 
    the miner's noise exposure to within MSHA's current 90 dBA PEL. This 
    barrier can be constructed at minimal cost from used conveyor belting.
        3. Exhaust mufflers. In addition to an environmental cab or barrier 
    shield, diesel powered equipment can be equipped with an effective 
    exhaust muffler. The end of the muffler's exhaust pipe should be 
    located as far away from the equipment operator as possible, and the 
    exhaust directed away from the operator. For underground mining 
    equipment, exhaust mufflers are generally not needed where water 
    scrubbers are used. A water scrubber offers some noise reduction and 
    the addition of an exhaust muffler may create excessive back pressure 
    or interfere with the proper functioning of the scrubber. However, 
    exhaust mufflers can be installed on underground equipment where 
    catalytic converters are used.
        Exhaust mufflers can also be installed on pneumatically powered 
    equipment. For example, exhaust mufflers are offered by the 
    manufacturers of almost every jackleg drill, chipping hammer, and jack 
    hammer. In the few cases where such exhaust mufflers are not available 
    from the factory, they can be easily constructed by the mine operator. 
    MSHA has a videotape available showing the construction of such an 
    exhaust muffler for a jackleg drill. This muffler can be constructed at 
    minimal cost from a section of rubber motorcycle tire.
        4. Acoustical materials. Various types of acoustical materials can 
    be strategically used to block, absorb, and/or dampen sound. Generally 
    such materials are installed on the inside walls of equipment cabs or 
    operator compartments and in control rooms and booths. For example: 
    barrier and
    
    [[Page 66413]]
    
    absorptive materials can be used to reduce noise emanating from the 
    engine and transmission compartments; and acoustic material can be 
    applied to the firewall between the employee and transmission 
    compartment. Noise reduction varies depending upon the specific 
    application. Care must be taken to use acoustical materials that will 
    not create a fire hazard.
        5. Control rooms and booths. Acoustically treated control rooms and 
    booths are frequently used in mills, processing plants, or at portable 
    operations, to protect miners from noise created by crushing, 
    screening, or processing equipment. Such control rooms and booths 
    typically are successful in reducing exposures of employees working in 
    them to below 85 dBA.
        6. Substitution of equipment. In a few cases, where sound levels 
    are particularly severe, and neither retrofit nor factory controls are 
    available, the equipment may need to be replaced with a quieter type. 
    For example, hand-held channel burners had been used for many years to 
    cut granite in dimension stone quarries. These were basically small jet 
    engines on a pole, fueled by diesel fuel and compressed air. The pole 
    was held by the channel burner operator and the flame was directed 
    against the granite. The intense heat caused the granite to spall and 
    by moving the flame back and forth a channel could be created. Sound 
    levels typically exceeded 120 dBA at the operator's ear.
        Several years ago, alternative and quieter methods of cutting the 
    granite were developed. These included replacing the channel burner 
    with either a diamond wire saw, hydraulic or pneumatic slot drill, or 
    water jet. Dimension stone operators were notified by MSHA of the 
    availability of these alternatives and given time to phase out the use 
    of diesel-fueled, hand-held burners and replace them with one of the 
    quieter alternatives. MSHA also has a videotape describing these 
    various alternatives.
        7. New equipment design. Using the channel burners as an example, a 
    new design of channel burner was engineered which automated the 
    process. The hand-held channel burners can be replaced with automated 
    channel burners using liquid oxygen. The automated design does not 
    require the operator to be near the channel burner, thereby using 
    distance to attenuate the noise.
        In addition to the noise controls described in MSHA's Program 
    Policy Manual, Volume IV, a number of other documents are available 
    describing effective noise controls for coal, metal and nonmetal 
    mines--controls for underground equipment and controls for surface 
    equipment.
        The MSHA document entitled, ``Summary of Noise Controls for Mining 
    Machinery,'' (Maraccini et al., 1986) provides case histories of 
    effective noise controls installed on specific makes and models of 
    mining equipment. The case histories describe the controls used, their 
    cost, and the amount of noise reduction achieved. MSHA believes that 
    the controls utilized in these specific cases can be extended to other 
    pieces of mining equipment.
        Furthermore, the former USBOM, which has been responsible for 
    conducting research leading to improved equipment and methods for 
    controlling safety and health hazards in mining, published a handbook 
    entitled, ``Mining Machinery Noise Control Guidelines, 1983.'' 
    (Bartholomae and Parker, 1983) This handbook describes engineering 
    noise controls for coal, metal and nonmetal mining equipment. The 
    former USBOM also published numerous documents describing noise 
    controls for mining machinery. Many of these research reports are 
    listed in the USBOM publication IC9004, ``The Bureau of Mines Noise-
    Control Research Program--A 10-Year Review.'' (Aljoe et al., 1985) Part 
    V of this preamble contains a list of USBOM publications dealing with 
    particular types of equipment.
        In particular, these include noise control methods for coal cutting 
    equipment, longwall equipment, conveyors, and diesel equipment. 
    Underground coal mining equipment may require some unique noise 
    controls. However, for coal cutting machines such as continuous miners 
    and longwall shears, the use of remote control is the single most 
    significant noise control. The installation of noise dampening 
    materials and enclosure of motors and gear cases can be used to aid in 
    controlling noise of coal transporting equipment such as conveyors and 
    belt systems. Diesel equipment used underground can use controls 
    similar to those used on surface equipment. Mufflers, sound controlled 
    cabs, and barriers will provide much of the needed noise control for 
    this type of equipment.
        Finally, while MSHA is not making any assumptions about the 
    development of new technologies, it would be interested to learn of any 
    processes under development that could further assist mine operators in 
    controlling noise. For example, the former USBOM (Burks and 
    Bartholomae, 1992) has developed a variable speed chain conveyor which 
    can be used to reduce the noise exposure of continuous miner operators 
    and loading machine operators in particular. An empty conveyor is 
    noisier than a full one because the coal covering the conveyor inhibits 
    the radiation of noise. The variable speed chain conveyor only operates 
    when necessary to convey coal. To date the manufacturers of mining 
    machines have apparently not adopted this technology, despite the fact 
    that it has the added benefits of reduced dust emissions, reduced power 
    consumption, and reduced maintenance costs.
        Although most of the USBOM noise control documents are not 
    specifically discussed in this section, MSHA has reviewed them. The 
    reviewed documents are listed in the references and are available to 
    the mining community. For additional information on USBOM noise control 
    projects contact: Mr. Edward D. Thimons, U.S. Department of Energy, 
    Pittsburgh Research Center, P.O. 18070, Pittsburgh, PA 15236, (412) 
    892-6683, Fax (412) 892-4259.
    Posting of Administrative Control Procedures
        The proposal would require that the mine operator post a copy of 
    any administrative controls in effect on the mine bulletin board, and 
    provide affected miners with a copy. As required by Section 109 of the 
    Mine Act, a mine operator must have a bulletin board. Documents 
    containing pertinent mine information are required to be posted by 
    various mandatory standards (e.g., training plan, emergency 
    communication numbers, MSHA citations, etc.). This is an ideal place to 
    require the administrative procedures to be posted, since most miners 
    are familiar with its location and the importance of documents placed 
    on it.
        The existing MSHA coal noise regulations do not require written 
    administrative controls, unless these controls are part of a hearing 
    conservation plan. Further, if written, the administrative controls are 
    not required to be posted. However, the affected miner would be 
    informed of the administrative procedures as part of his/her required 
    part 48 training. Neither MSHA's current metal and nonmetal nor OSHA's 
    noise regulations require that administrative controls, if used, be in 
    writing and posted.
        MSHA did not receive any comments on this issue.
        MSHA has concluded that it is important that administrative 
    controls be posted, since miners must actively comply for the controls 
    to be effective. Posting would facilitate informing miners of work 
    practices necessary for
    
    [[Page 66414]]
    
    reducing their noise exposures, especially when temporarily assigned to 
    a different job. Since the administrative controls must be in writing 
    to be posted on the mine bulletin board, MSHA believes that providing 
    the affected miners with copies would not be a significant burden as 
    compared to other possible methods of notification and is likely to be 
    more much more effective in ensuring miners are on notice of their 
    obligation to comply.
    Supplementary Controls
        Under proposed Sec. 62.120(b), any miner exposed above the action 
    level will receive special training in noise protection, and be 
    enrolled in a hearing conservation program in which annual audiometric 
    tests are offered. Any miner exposed above that level is to receive 
    hearing protection upon request, as is any miner who incurs an STS or 
    who is waiting for a baseline audiogram. The operator must ensure 
    hearing protection is worn, however, in only two cases: if there is an 
    STS, and if it will take more than 6 months to get the baseline 
    audiogram because of the need to wait for a mobile test van.
        Under proposed Sec. 62.120(c), if exposures exceed the PEL, and 
    cannot be feasibly reduced to the PEL through the use of all feasible 
    engineering and administrative controls, a few additional requirements 
    would be applicable. All miners so exposed must be provided hearing 
    protection, and required to use the hearing protection. In addition, 
    the operator would be required to ensure that miners take the scheduled 
    audiometric examinations.
        The circumstances under which hearing protection must be worn are 
    discussed more fully in connection with proposed Sec. 62.125.
        MSHA is proposing that mine operators require miners enrolled in an 
    HCP to participate in audiometric testing once exposures exceed the 
    PEL. This is not the case under OSHA; however, MSHA believes this 
    approach is warranted in the mining industry.
        The information generated by these tests can serve as triggers for 
    both the mine operator and the Agency to investigate more thoroughly 
    the implementation of noise controls. If an employee incurs a standard 
    threshold shift, at the very least a hearing protector needs to be 
    provided or changed. The audiological information can provide useful 
    clues to the noise causing the problem, and point to an undetected 
    failure of various controls: engineering controls, administrative 
    controls, or the failure to properly fit, maintain or utilize hearing 
    protectors. If an employee incurs a reportable hearing loss, it is an 
    indication that despite regular MSHA inspections, some serious problem 
    has not been detected or resolved and a more thorough analysis is 
    probably required. If the required audiological examinations are not 
    taken, standard threshold shifts and cases of reportable hearing loss 
    will go unreported.
        In addition, the Agency wants to ensure that miners are aware of 
    the severity of any hearing loss; in a mining environment, this 
    knowledge could have implications for the safety of the miner and the 
    safety of others. Miners who do not recognize that they have a hearing 
    problem--and hearing loss occurs gradually and is often hard for 
    individuals to accept--may be less willing than those who have been 
    advised they have a problem to pay attention to the problem. The 
    proposed regulation provides for annual training, but a notification of 
    a detectable change in hearing acuity would certainly help to focus 
    attention.
        The Agency is concerned that unless such participation is 
    mandatory, the cost of the examinations, however limited, might create 
    an incentive for mine operators to encourage miners to waive the 
    examinations. Concern about the implications of health examinations on 
    their job security may likewise discourage miners from taking 
    examinations. The voluntary X-ray surveillance program currently 
    offered to coal miners has a poor record of participation. This is not 
    an unusual situation in the mining industry, where retention of good, 
    well-paying jobs is a priority for most workers.
        Finally, it should be noted that audiometric testing is not an 
    invasive procedure. No damaging radiation is involved, nor is there any 
    penetration with a needle or other device.
        Comments on this provision are specifically solicited. In 
    particular, experience from companies in which such examinations are 
    mandated would be welcome. The Agency recognizes there may be concern 
    on the part of some miners that if mine operators are provided with 
    audiometric information, it could lead to the discharge of miners who 
    are developing hearing loss problems so as to minimize potential 
    workers' compensation claims.
    Dual Hearing Protection
        Proposed Sec. 62.120(d) would require that, in addition to the 
    controls required for noise exposure that exceed the PEL, a mine 
    operator provide dual hearing protectors to a miner whose noise 
    exposure exceeds a TWA8 of 105 dBA during any workshift, a dose of 
    800% of the PEL. The mine operator must also ensure that they are worn. 
    An earplug type protector would be worn under an earmuff type 
    protector.
        Currently, neither MSHA nor OSHA specifically mandate the use of 
    dual hearing protection. In practice, however, existing rules require 
    dual hearing protection under some circumstances.
        Under current Coal and Metal and Nonmetal noise policy, dual 
    hearing protection would be required whenever the attenuation of a 
    single hearing protector does not reduce the miner's noise exposure to 
    within the PEL.
        Also, due to MSHA's current procedures for determining the 
    attenuation of hearing protectors (discussed under Hearing protector 
    effectiveness of this preamble), dual hearing protection would almost 
    always be required when miners are exposed to sound levels above 112 
    dBA. As discussed below, the attenuation provided by dual hearing 
    protectors is less than the sum of their individual attenuations. MSHA 
    policy currently specifies that 6 dB be added to the attenuation of the 
    hearing protector having the higher attenuation.
        OSHA requires that ``adequate'' hearing protection be provided to 
    and worn by workers. Employers would thus have to utilize dual hearing 
    protection in some cases to get the needed attenuation. However, no 
    specific dose level triggering dual hearing protection level has been 
    established by OSHA.
        No commenter addressed the exposure above which dual hearing 
    protection would be required. One commenter suggested that MSHA 
    consider dual hearing protection to provide 5 dB more attenuation than 
    the hearing protector with the higher attenuation. Another commenter, 
    disagreed with current MSHA Metal and Nonmetal policy and believed that 
    more than 6 dBA credit should be given above the attenuation of the 
    higher component (earplug or earmuff) when dual hearing protectors are 
    worn. This commenter did not, however, specify how much credit should 
    be given.
        Research has demonstrated that dual hearing protection affords the 
    wearer greater attenuation than either earplugs or earmuffs alone. 
    Berger in EARLOG 13 (1984) has shown that the use of dual hearing 
    protectors provides greater attenuation. The attenuation of the dual 
    hearing protection is at least 5 dB greater than the attenuation of 
    either hearing protector alone. This attenuation, however, is much less 
    than the sum of the individual Noise Reduction Rating (NRR) values and 
    is dependent on the frequency. Dual hearing protectors are especially 
    important for noise which is dominated
    
    [[Page 66415]]
    
    by low to middle frequency sounds. The performance of dual hearing 
    protectors is not influenced greatly by the selection of the earmuff; 
    however, the selection of the earplug has a strong influence on the 
    attenuation below 2000 Hz. For noises which are dominated by sounds 
    above 2000 Hz, the attenuation of dual hearing protectors is limited by 
    flanking bone conduction paths to the inner ear. Berger recommends dual 
    hearing protectors whenever the TWA8 exceeds 105 dBA.
        Michael (1991) believes that, because of complex coupling factors, 
    the attenuation from wearing both earplugs and earmuffs cannot be 
    predicted accurately. If the attenuation of the earplug and earmuff is 
    about the same at a given frequency, then the resultant attenuation 
    should be 3 to 6 dB greater than the higher of the two individual 
    attenuations. However, if one attenuation is much greater than the 
    other, then the resultant attenuation will be slightly more than the 
    higher attenuation.
        Nixon and Berger (1991) report that earplugs, worn in combination 
    with earmuffs or helmets, typically provided more attenuation than 
    either hearing protector alone. The gain, in attenuation at individual 
    frequencies, varies between 0 to 15 dB. At or above 2000 Hz, the 
    attenuation of the combination is limited by bone conduction to 
    approximately 40 to 50 dB. Below 2000 Hz, the selection of the earplug 
    is critical for increasing the attenuation. There is little change in 
    the attenuation of different types of earmuffs at frequencies below 
    2000 Hz.
        Bertrand and Zeiden (1993) determined that miners exposed to sound 
    levels of 118 dBA were afforded protection consistent with a sound 
    level of 98 dBA by the use of earmuffs. The earmuff had an NRR of 24 
    dB. Consequently, the earmuff alone could not provide attenuation 
    sufficient to protect the miner's hearing acuity.
        Research has clearly demonstrated that dual hearing protection 
    provides greater attenuation than either hearing protector alone. 
    Further, the U.S. armed services require dual hearing protection for 
    workers exposed to high sound levels. MSHA concurs that the additional 
    attenuation afforded by the use of dual hearing protection is necessary 
    to protect miners who are exposed to high sound levels. Furthermore, 
    MSHA has concluded that a TWA8 of 105 dBA (800%) is a prudent 
    level above which dual hearing protection should be required. This 
    level of noise exposure can quickly damage the hearing acuity of the 
    exposed miner.
    Dose Ceiling
        Although the statement of the PEL in Sec. 62.120(c) is absolute 
    that no miner shall be exposed to noise above a TWA8 of 90 dBA, 
    the remainder of that paragraph and paragraph (d) deal with situations 
    where in fact miners are going to be exposed to noise in excess of the 
    PEL for some period of time--due to the economic feasibility of 
    administrative and engineering controls for a particular mine operator, 
    or due to the technological feasibility of engineering controls as to a 
    particular operation. The seriousness of this situation for miners is 
    indicated by the fact that MSHA is proposing that dual hearing 
    protectors be required at a TWA8 of 105 dBA: a noise dose of 800%.
        The Agency is interested in comments on whether there is some noise 
    dose which should be established as an absolute dose ceiling by the 
    regulation, regardless of the implications for a particular mine 
    operator or operation. The circumstances in which this might pose a 
    problem for the mining industry appear to be very limited. While coal 
    inspection data over the years have indicated some exposures over 800%, 
    MSHA believes these are anomolies for which well-known controls are 
    available. If there are problems, they are likely to be in the metal 
    and nonmetal sector.
        On the one hand, the dual-survey data indicate that using the 80 
    dBA threshold level, only about one-quarter of one percent (0.28%) of 
    metal and non-metal exposures exceed a noise dose of 800%. The data 
    indicate, however, that there remain a few specific job categories in 
    the metal and nonmetal sector which experience a significant problem 
    with noise exposures of this dimension, as indicated in Table III-6. 
    The sample size is provided to illustrate that in some cases, the 
    percentages are based on limited data.
    
       Table III-6: Metal/Nonmetal Job Categories in Which More Than 1% of  
           Recorded Exposures Are Over a TWA8 of 105 dBA (800% of PEL)      
    ------------------------------------------------------------------------
                                                  No. >    No. of    Percent
          Code              Job category           105     sample     > 105 
    ------------------------------------------------------------------------
    134............  Jet-piercing channel              5         9        56
                      operator.                                             
    234............  Jet-piercing drill                1         3        33
                      operator.                                             
    058............  Drift miner..............        15        55        27
    057............  Stope miner..............         9        39        23
    534............  Jackleg or stopper drill          7        31        23
                      operator.                                             
    434............  Churn drill operator.....         1         7        14
    334............  Wagon drill operator.....         3        30        10
    034............  Diamond drill operator...         3        46         7
    046............  Rock or roof bolter......         2        38         5
    734............  Rotary (pneumatic) drill         20       478         4
                      operator.                                             
    634............  Rotary (electric or              11       544         2
                      hydraulic) drill                                      
                      operator.                                             
    934............  Jumbo percussion drill            2       111         2
                      operator.                                             
    399............  Dimension stone cutter            3       301        1 
                      and polisher; rock sawer.                             
    ------------------------------------------------------------------------
    Notes: Miscellaneous job categories where less than 1% of recorded      
      exposures exceeded TWA8 of 105 dBA are not displayed. Numbers are for 
      four year period, 1991-1994.                                          
    
        The job descriptions do not necessarily indicate the equipment in 
    use; for example, the stope miners and drift miners may well have been 
    using the same equipment as the jackleg drill operators. Based on the 
    Agency's experience, there are only a few pieces of equipment used in 
    mining for which no control other than multiple hearing protectors is 
    currently available.
        The data illustrate that many exposures at this level are 
    preventable. Even with the jackleg drills more than 75% of the 
    exposures were controlled to less than a TWA8 of 105 dBA. The data 
    base from which the above information was drawn found nine bulldozer 
    operators and three truck drivers
    
    [[Page 66416]]
    
    exposed to noise above 800% of the PEL; and while these constituted 
    only a small fraction of the samples of those job categories, 0.7% and 
    0.05% respectively, the Agency is disturbed to find any such samples at 
    all given that the metal and nonmetal industry has for some years been 
    operating under a requirement to use engineering and administrative 
    controls to bring sound levels down to the PEL or as close thereto as 
    is feasible.
        Accordingly, MSHA requests comment on whether there should be an 
    absolute dose ceiling, regardless of the economic feasibility of 
    control by an individual mine operator, and what that should be. MSHA 
    also requests comment on whether such a dose ceiling should be 
    technology forcing--i.e. apply regardless of the technological 
    feasibility of currently available controls.
    Ceiling Level
        Proposed Sec. 62.120(e) would retain MSHA's current 115 dBA ceiling 
    level for continuous and intermittent noise. The 115 dBA ceiling level 
    is intended to protect individuals from high sound levels which last 
    longer than those typically characterized by impulse/impact noise.
        The 115 dBA ceiling level originated out of the Walsh-Healey Public 
    Contracts Act which formed the basis of current Department of Labor 
    noise regulations. OSHA, in its 1974 proposed noise standard (39 FR 
    37775), specified that the 115 dBA limit was a maximum steady state 
    sound level which was not to be exceeded regardless of the time-
    weighted average dose computation.
        In its ANPRM, MSHA did not specifically request comments on the 115 
    dBA ceiling limit. One commenter, however, presented a view on the 115 
    dBA level. This commenter stated that ``Few professionals would allow a 
    worker to remain unprotected while exposed to 115 dBA for 15 minutes.''
        MSHA's review of available literature found a diversity of opinions 
    on the choice of a ceiling level for exposures to continuous and 
    intermittent noise.
        At the 93rd Meeting of the Acoustical Society of America, Johnson 
    and Schori (1977) reported that 115 dBA for 15 minutes may be grossly 
    under protective, while an upper limit of 115 dBA, regardless of the 
    time of the exposure, is unduly restrictive. For example, they found 
    significant temporary threshold shift from exposure to 115 dBA for only 
    2.7 minutes. On the other hand, they found virtually no such shift from 
    exposure to 130 dBA for 10 seconds and minimal shift (median of 2 dB) 
    when exposed to 120 dBA for 40 seconds--although MSHA would point out 
    it knows of no mining tasks taking such a limited time. In any event, 
    this shows that the ceiling limit is dependent upon both time and 
    intensity.
        Cluff (1984) stated that ``The selection of 115 dBA for 15 minutes 
    is arbitrary and represents several contradictions.'' He agreed with 
    Johnson, however, that exposures to 115 dBA for 15 minutes is 
    dangerous. Cluff stated that ``this danger is magnified by extending 
    the 5 dB rule to 130 dBA'' and suggested that a 3-dB or 4-dB exchange 
    rate may have merit as a solution.
        Others discussed different ceiling limits to prevent temporary 
    threshold shift which may lead to a permanent NIHL. The U.S. Army's 
    Technical Memorandum 13-67, ``Criteria for Assessing Hearing Damage 
    Risk from Impulse-Noise Exposure'' (Coles, 1967) stated that:
    
        It has been customary in steady-state noise DRC [damage risk 
    criteria] * * * to include an upper limit of about 135 dB for 
    unprotected noise exposure for any duration, however short. In most 
    cases it is understood by implication only, rather than by direct 
    statement, that this restriction is not intended to apply to impulse 
    noise * * *
    
        The technical memorandum, however, stated further that:
    
        The relationship between TTS [temporary threshold shift] 
    resulting from a single noise exposure and permanent threshold shift 
    (PTS) to be expected from habitual exposure is not known with 
    certainty even for steady-state noise.
    
        In Acoustic Parameters of Hazardous Noise Exposures, however, 
    Henderson (1990) discussed a critical level above which damage by 
    acoustic trauma begins. He stated that:
    
        At levels above 120 dB SPL [sound pressure level] the cochlea 
    begins to be damaged by direct mechanical destruction, i.e., the 
    organ of Corti can be lifted off the basilar membrane, tight-cell 
    junctions can be ripped apart, and the tympanic membrane can be 
    ruptured. The level at which mechanical damage occurs has been 
    called the ``critical level,'' but it is important to recognize that 
    there is not a critical level but rather a transition point that is 
    related to the spectrum and temporal pattern of the exposure.
    
        CHABA (1993) believed that single exposure to sound levels above 
    140 dBA can permanently damage hearing. Furthermore, the threshold for 
    pain is dependent upon the frequency of the noise. This threshold lies 
    between 135 and 140 dB.
        Ward (1990) stated that:
    
        * * * a ``critical exposure'' for production of immediate severe 
    loss, presumably associated with structural failure in the cochlea 
    rather than with metabolic fatigue, is dependent not on the energy 
    in the exposure (p2t) but on a different quantity given by 
    integrating the fourth power of the pressure over time. * * * The 
    best estimate for the critical exposure in man is around 1011 
    Pa4-sec for a median value, although individual differences in 
    susceptibility and vulnerability mean that the range will be very 
    great.
    
        NIOSH (1995) recommends that the 115 dBA ceiling limit be retained. 
    Citing recent medical research, NIOSH believes that the critical level 
    is between 115 and 120 dBA. Above the critical level, immediate 
    structural damage to the ear occurs. This structural damage causes a 
    loss of hearing acuity.
        ACGIH (1994) recommended that exposures to occupational noise 
    should not be permitted above 139 dBA. Further, for sound levels equal 
    to or exceeding 103 dBA, ACGIH believes that the exposure be ``limited 
    by the noise source--not by administrative control.''
        As illustrated by the above discussed studies, there is no 
    consensus among the scientific community as to a sound level above 
    which permanent damage occurs (regardless of the duration of exposure). 
    However, many researchers believe the critical level is slightly above 
    115 dBA and is time dependent with an allowable duration of less than 
    15 minutes.
        International communities and selected branches of the U.S. armed 
    services specify a ceiling level; however, there is no agreement among 
    these groups either.
        There are relatively few noise sources in the mining industry that 
    produce sound levels exceeding 115 dBA (e.g., unmuffled pneumatic rock 
    drills and hand-held channel burners). However, these sources often 
    operate during most of the work shift with resulting full-shift noise 
    exposure considerably over the PEL. Currently, MSHA surveys these noise 
    sources by taking spot readings with Type 2 sound level meters rather 
    than conducting full-shift sampling with a personal noise dosimeter. 
    The requirements for Type 2 sound level meters are in ANSI S1.4-1983, 
    ``Specification for Sound Level Meters.'' MSHA intends to continue 
    sampling these sources using a sound level meter.
        Even though this proposal has retained the 115 dBA ceiling level 
    for noise exposure, sound levels above 115 dBA are to be included in 
    the determination of the noise dose. The Agency has determined that it 
    is important to include sound levels above 115 dBA in the noise dose so 
    that the miner's noise exposure is accurately assessed. By having an 
    accurate assessment, the mine operator will be
    
    [[Page 66417]]
    
    able to provide hearing protectors with maximum attenuation and take 
    steps to ensure that the hearing protectors are effectively fitted and 
    properly worn.
        MSHA believes that exposure to sound levels exceeding 115 dBA, 
    regardless of duration, may potentially result in acute hearing loss 
    among susceptible individuals. Although there is a lack of scientific 
    consensus on the exact time of safe exposure, the majority believe that 
    15 minutes is hazardous. Accordingly, MSHA believes retention of the 
    current ceiling is warranted. The Agency, however, welcomes additional 
    comment on this issue.
    Exposure Determination by Operators
        Proposed Sec. 62.120(f)(1) would require mine operators to 
    establish a system of monitoring which effectively evaluates each 
    miner's noise exposure. This will ensure that mine operators have the 
    means to determine whether a miner's exposure exceeds any of the 
    limitations established by this section, as well as to assess the 
    effectiveness of noise controls. The proposed rule is performance 
    oriented in that the regularity and methodology used to make this 
    evaluation are not specified. Specific requirements for periodic 
    monitoring by qualified persons now applicable to the coal sector would 
    be revoked.
        Under the approach proposed, mine operators may design a monitoring 
    program suitable for each specific mine site. Mine operators would be 
    expected to utilize survey methods and instrumentation which are 
    scientifically valid and based on sound industrial hygiene practice.
        Although calibration requirements are not specifically mandated in 
    the proposal, good industrial hygiene practice dictates that any 
    instrumentation used for determining a worker's occupational exposure 
    to a contaminant, in this case noise, be calibrated. The calibration 
    program should be composed of three phases--type testing of 
    instruments, laboratory calibration of the instruments, and field 
    calibration. Seiler and Giardino (1996) discussed the importance of 
    each of these classes of calibrations.
        Briefly, type testing is an exhaustive testing of a model of 
    instrument to ascertain that it complies with a standard, such as the 
    ANSI standard for personal noise dosimeters. Laboratory calibration is 
    an extensive calibration that ascertains that an individual instrument 
    meets factory specifications. Finally, field calibration is a brief 
    procedure conducted before and after a survey to ascertain that an 
    instrument is operating properly.
        The mine operator has the responsibility of accurately determining 
    a miner's noise exposure. In order to do this properly the type of 
    instrumentation needs to be considered. In the cramped quarters of an 
    underground mine and on mobile mining equipment, it may not be possible 
    to accurately evaluate a miner's noise exposure without endangering the 
    technician if a sound level meter is used. Other occupations cannot be 
    sampled with a sound level meter because the most exposed ear is not 
    accessible to the technician. For the above occupations, a personal 
    noise dosimeter would need to be used. An analysis of noise exposures 
    collected from 1986 through 1992 by the MSHA coal inspectorate revealed 
    that 21.8% of the occupations could only be sampled using personal 
    noise dosimeters. These occupations comprised nearly 60% of the surveys 
    conducted by the inspectors.
        A program would be expected to evaluate noise exposure in adequate 
    detail to enable the mine operator to reasonably determine which miners 
    work in areas requiring the institution of the controls that may be 
    required. Sufficient evidence of a noise monitoring program must be 
    available during mine inspections to permit the evaluation by MSHA of 
    the program's effectiveness. The Agency will also take its own surveys 
    of noise exposure during inspections to ascertain miner exposure and to 
    evaluate the effectiveness of the mine operator's monitoring program.
        MSHA believes that this proposal affirms a mine operator's 
    obligation to take the action needed to determine whether or not a 
    miner is in compliance with the exposure limitation requirements of the 
    proposed regulation. At the same time, it allows mine operators maximum 
    flexibility for determining a miner's noise exposure.
        MSHA believes that mine operators have a number of incentives to 
    monitor sound levels on a regular basis to ensure they can:
        (1) Avoid the costs associated with needlessly including or 
    retaining a miner in an HCP or providing special noise training;
        (2) Assess the effectiveness or need for either engineering or 
    administrative controls or a combination of these controls to meet the 
    TWA8 of 90 dBA;
        (3) Document the miner's exposure for workers' compensation 
    purposes;
        (4) Provide information to health professionals evaluating miners' 
    health and audiograms; and
        (5) Avoid citations and penalties during the regular Agency 
    inspections in the mining industry for failure to comply with the 
    standard's requirements.
        The results of operator monitoring will not be sent to MSHA, nor 
    will monitoring results be used to determine compliance with the 
    applicable noise standard. Mine operators are, however, under an 
    obligation to take certain actions based upon any noise measurements 
    they conduct. Proposed Sec. 62.120 requires mine operators to take 
    specific corrective action when a miner's noise exposure exceeds the 
    various limitations set forth in the section. It also requires that 
    miners be notified whenever a mine operator determines that their noise 
    exposure exceeds the action level.
        The requirements of proposed Sec. 62.120(a), as to how noise is to 
    be measured for the purposes of this proposal, would need to be 
    followed by mine operators in their monitoring. These requirements 
    include: disregarding the attenuation of any hearing protector worn by 
    the miner, integrating all sound levels from 80 dBA to at least 130 dBA 
    during a miner's full workshift, using a 90 dBA criterion level and a 
    5-dB exchange rate, and using an A-weighting and slow-response 
    instrument setting. Mine operators would, of course, be free to take 
    any additional measurements that they deem appropriate: for example, 
    taking peak-response readings to measure any impact/impulse noise.
        MSHA current coal noise standards (30 CFR Secs. 70.500/71.800) 
    require mine operators to monitor each miner's noise exposure twice a 
    year and certify the results to MSHA. These standards also specify when 
    and how to sample, who is qualified to sample, and reporting 
    requirements.
        MSHA's noise standards (30 CFR Secs. 56/57.5050) for metal and 
    nonmetal mines do not contain any operator sampling requirements, 
    although they do require that mine operators maintain exposures in 
    compliance with the PEL. In order to do this effectively, many metal 
    and nonmetal mine operators conduct their own monitoring.
        OSHA's noise standard requires employers to implement a monitoring 
    program when information indicates that any employee's noise exposure 
    may equal or exceed the action level (TWA8 of 85 dBA). OSHA allows 
    employers to use representative personal or area sampling; however, in 
    areas with significant variations in sound level or high worker 
    mobility, the employer would have to show that area sampling produces 
    results equivalent to personal sampling. OSHA also requires the
    
    [[Page 66418]]
    
    employer to repeat the monitoring in specific situations.
        MSHA's ANPRM solicited comments on the frequency of monitoring, the 
    sampling strategy, and the use of the information obtained. The ANPRM 
    also asked whether specification-oriented or performance-oriented 
    requirements would be more appropriate. At that time, the Agency 
    solicited comments based on the premise that the proposed rule would 
    include a detailed monitoring requirement and the commenters responded 
    accordingly. However, since MSHA has decided not to propose detailed 
    monitoring requirements, the Agency has not addressed specific issues 
    regarding area versus personal monitoring, instrumentation 
    specifications, calibration requirements, or other related monitoring 
    issues.
        Many commenters preferred performance-oriented standards, similar 
    to OSHA's, that would allow mine operator discretion in when and how to 
    sample. One of these commenters stated:
    
        The goal of the monitoring effort should not be simply to 
    collect noise exposure data, but rather to accomplish the goal of 
    eliminating job-related noise induced hearing loss. With this goal 
    in mind, the operator would need to have collected noise exposure 
    information on the jobs that he had reason to believe were above the 
    85 dBA action level. This information would be necessary to identify 
    those workers that should be included in the HCP as well as areas 
    and equipment where noise controls are needed.
        If the operator does not choose to monitor for noise, he should 
    have an alternate plan that accomplished the same goal: i.e., 
    includes all non-office workers in the HCP regardless of noise 
    exposure, perform a sound level survey to identify mandatory hearing 
    protection areas and equipment, etc. It is recommended that MSHA 
    adopt the logic outlined in the OSHA noise standard, 29 CFR 
    1910.95(d) (1), (2) and (3).
    
        Conversely, two commenters recommended a specification-oriented 
    rule. One of these recommended personal monitoring on an annual basis 
    and the other simply recommended personal or area monitoring.
        Finally, two commenters had a different view on monitoring. They 
    recommended that MSHA, rather than the mine operator, conduct all 
    monitoring for the purpose of this proposed standard. In response to 
    these commenters, the Agency would point out that it is the 
    responsibility of mine operators to ensure the safety and health of 
    their miners. MSHA sampling programs are to audit the mine operators to 
    ensure the protection of miners. Moreover, MSHA does not have the 
    resources to sample every miner annually. Metal and Nonmetal has 
    specific health sampling guidelines which require periodic sampling of 
    selected mining occupations. MSHA currently conducts over 20,000 full-
    shift noise exposure surveys in the mining industry annually. Although 
    MSHA intends to continue measuring the noise exposure of miners in 
    order to determine compliance, it can only sample a small percentage of 
    the exposed mining population annually. Mine operators are responsible 
    for knowing at all times when their employees exceed applicable limits 
    so that appropriate action can be taken.
        The Agency, however, is willing to share its sampling results and 
    analyses of these results with the mining industry. Mine operators who 
    do not conduct their own monitoring could use the MSHA data along with 
    information from equipment manufacturers to estimate a miner's noise 
    exposure. This could be beneficial to all mine operators, particularly 
    small mine operators with limited resources. If, however, as a result 
    of this proposal, MSHA changes the threshold, prior sampling conducted 
    by the Agency may not provide an accurate indication of whether a 
    miner's noise exposure exceeds the new standard.
        Although a mine operator could use prior MSHA sampling results, and 
    information from equipment manufacturers, such use would not relieve 
    the mine operator of responsibility to appropriately determine a 
    miner's noise exposure. Therefore, it would behoove mine operators to 
    determine a miner's noise exposure by methods comparable to those which 
    would be used by MSHA, as outlined in Sec. 62.120(a).
        Although numerous commenters and organizations supported the need 
    for monitoring, most favored a performance-oriented approach and did 
    not specify a procedure to be followed. MSHA agrees. The Agency 
    believes that the focus of the noise standard should be on preventing 
    NIHL and reducing miners' noise exposures and that it would be 
    counterproductive to specify detailed monitoring requirements or 
    procedures. Also, the Agency does not want to stifle improvements in 
    monitoring technology or methodology.
        Moreover, the Agency believes that the current specification-
    oriented coal operator monitoring produces results that in fact are not 
    representative of miners' noise exposure. For example, in FY 1994, coal 
    mine operators conducted approximately 180,000 noise surveys (two per 
    miner) and found 36 miners to be overexposed (their exposures exceeded 
    132%). However, MSHA does not know the extent to which mine operators 
    may be including credit for the wearing of hearing protection in the 
    determination of the miner's exposure. Conversely, MSHA conducted 6,339 
    surveys in coal mines and found 857 exposures exceeding the 132%. 
    However, only 62 of these surveys resulted in a violation due to credit 
    being given for use of hearing protection. This indicates that despite 
    having specification-oriented monitoring requirements, current operator 
    sampling in coal mines may not be providing results consistent with 
    those found by MSHA.
        For monitoring compliance with this proposal, the Agency intends to 
    use validated scientific methodology. Current MSHA sampling procedures 
    and policies are listed in MSHA's Program Policy Manual and its Coal, 
    and Metal and Nonmetal, Health Inspection Procedures Handbooks. Copies 
    of these documents are available for review and copying in MSHA 
    offices. MSHA's sampling procedures, however, would be modified to be 
    consistent with Sec. 62.120(a) of this proposal once the rule is 
    finalized.
        Currently, MSHA bases its noise exposure compliance determinations 
    on personal full-shift sampling with a personal noise dosimeter. The 
    calibration of the personal noise dosimeters is checked before and 
    after each survey. Additionally, annual laboratory calibration is 
    conducted to assure measurement accuracy. The personal noise 
    dosimeter's microphone is positioned on the top of the miner's 
    shoulder, midway between the neck and the end of the shoulder, with the 
    microphone diaphragm pointing in a vertical upward direction. The 
    microphone is placed on the shoulder that is normally between the 
    principal noise source and the miner's ear. Sampling is conducted while 
    the miner performs his/her normal duties.
        In the development of this proposal, MSHA also reviewed the noise 
    monitoring programs of the U.S. Armed Services and other jurisdictions.
        Although MSHA has described its current noise sampling procedures, 
    the Agency may decide to modify or change these procedures based upon 
    new or improved sampling methods, instrumentation, or technology.
    Employee Notification
        Proposed Sec. 62.120(f)(2) would require that within 15 calendar 
    days of determining that a miner's exposure exceeds the action level, 
    the permissible exposure level, the dual hearing protection level, or 
    the ceiling level established by this section, the mine
    
    [[Page 66419]]
    
    operator notify the miner in writing of the overexposure and the 
    corrective action being taken. If the miner's exposure has not changed 
    from one of these levels to another, and the miner has been notified of 
    his exposure at that level within the past year, no notification needs 
    to be provided; if the level has changed, or there has been no 
    notification in the past year, notification is to be provided. The 
    proposal specifically states that these notifications are triggered by 
    exposure evaluations conducted either by the operator or by an MSHA 
    inspector.
        At the present time, MSHA does not require notification, though it 
    is implied in those cases in which a coal miner is enrolled in an HCP 
    for having exceeded the PEL. OSHA's standard requires that employees be 
    notified in writing of monitoring results that exceed the action level 
    within 21 days of the monitoring.
        The proposed requirement is consistent with Section 103(c) of the 
    Mine Act. Section 103(c) of the Mine Act states in pertinent part that:
    
        Each operator shall promptly notify any miner who has been or is 
    being exposed to * * * harmful physical agents * * * at levels which 
    exceed those prescribed by an applicable mandatory health or safety 
    standard promulgated under section 101 * * * and shall inform the 
    miner who is being thus exposed of the corrective action being 
    taken.
    
        Many commenters supported miner notification of all sampling 
    results and stated that such is current company policy. Several of 
    these commenters recommended that the specific method of notification 
    be left to the discretion of the mine operator. One commenter 
    specifically stated that through notification, ``the employee could 
    help facilitate a solution to the problem and be more committed to 
    following safety procedures.'' This commenter also stated that 
    ``requiring written notification is not effective when dealing with 
    persons who cannot read or do not have the background to understand the 
    meaning of the notification's contents.''
        A mining association commented ``* * * that miners should be made 
    aware when their exposure exceeds allowable limits * * *'' and that ``* 
    * * employees should have knowledge of their exposure and any 
    subsequent hearing loss. * * *'' This association suggested, however, 
    that notification ``* * * be in the form of entry into the HCP. * * *'' 
    Several other commenters recommended that MSHA's requirements be the 
    same as OSHA's.
        After reviewing the comments and the regulations from the U.S. 
    Armed Forces and international organizations, MSHA concludes that 
    notification should be provided for exposure at any level defined in 
    the proposed regulation. At the action level, there is a significant 
    risk of material impairment (as discussed in part II of this preamble). 
    Notification will be needed at this level because under the proposal, 
    if the noise exceeds that level, the mine operator would be required to 
    take protective action (hearing protectors and enrollment in an HCP). 
    Notification at this level would explain to the miners the reason why 
    it is necessary for them to wear their hearing protectors. Moreover, 
    since the harm occurs at this level, notification is required under 
    Sec. 103(c) of the 1977 Mine Act. Notification at the permissible 
    exposure level and dual hearing protection level--exposures 
    respectively 2 and 16 times the dose at the action level--is necessary 
    to ensure the miner understands the rationale for added protection and 
    the actions being taken by the mine operator to lower noise exposures. 
    The same is true for any exposures exceeding the ceiling level.
        MSHA believes there is no need to notify a miner of every exposure 
    determination, as long as the miner is cognizant of the general level 
    of his or her exposure--so that the miner pays attention to noise 
    exposure and noise abatement efforts (including the use of properly 
    fitted and maintained hearing protectors). If an exposure measurement 
    for a miner demonstrates a change in that miner's situation--e.g., from 
    below the PEL to over the PEL, or from over the PEL to above the dual-
    hearing protector level--the miners should be made aware of this fact.
        Moreover, even if the miner's situation has not changed, the miner 
    should be reminded of his or her overexposure when it is measured if 
    notification has not been made recently. MSHA welcomes comment on the 
    proper balance to strike between the need for notification and 
    nonproductive paperwork.
        MSHA has concluded that the notification should be in writing. This 
    would ensure that the miner does not misconstrue the measured level nor 
    the actions being taken.
    Warning Signs
        The proposed rule has no provision for requiring the posting of 
    warning signs. While MSHA acknowledges the value of posting warning 
    signs, the process is inherently complicated in the ever changing 
    mining environment, and MSHA believes the training requirements it is 
    proposing should ensure miners are apprised of noise hazards to which 
    they may be exposed.
        Section 101(a)(7) of the Mine Act requires that health or safety 
    standards promulgated by MSHA:
    
        * * * prescribe the use of labels or other appropriate forms of 
    warning as are necessary to insure that miners are apprised of all 
    hazards to which they are exposed, * * *
    
    Existing MSHA noise standards do not exercise this authority with 
    respect to noise, and do not require the posting of warning signs.
        When OSHA promulgated its Hearing Conservation Amendment, it did 
    not include a requirement for warning signs. OSHA stated in the 
    preamble to the final rule, that the use of warning signs to warn 
    employees about noise hazards in high noise areas should be left to the 
    discretion of the employer. In so doing, OSHA stated that noise is more 
    readily discernible than other harmful physical agents and therefore a 
    specific warning sign requirement may not be necessary to protect 
    employees, and that in certain circumstances such signs might confuse 
    rather than serve a useful educational purpose. OSHA also recognized 
    that the employer is more familiar with the workplace environment and 
    will be in a better position to determine if the posting of signs in a 
    given situation will aid in the success of the company's HCP. Further, 
    OSHA stated that other methods, such as training, may be more 
    appropriate for apprising employees of the hazards of noise.
        In its ANPRM, MSHA asked whether it should require warning signs in 
    areas exceeding a specified sound level, and what this sound level 
    should be. Numerous commenters specifically addressed the issue of 
    warning signs and were about equally divided over whether such a 
    requirement is necessary. Those commenters supporting the use of 
    warning signs varied considerably on criteria for their use. For 
    example, one commenter indicated that warning signs should only be 
    posted in areas where an immediate threat of injury exists, such as 
    areas with impact noise above 140 dB or constant noise above 115 dBA. 
    Other commenters said that warning signs should only be required on 
    non-mobile equipment, or in areas where the use of hearing protectors 
    is mandatory.
        Among those commenters that did not support the use of warning 
    signs, several stated that MSHA's standard should be performance-
    oriented and allow the mine operator to decide how to warn its 
    employees, such as through training, safety meetings, notification of 
    exposure results, etc. One commenter
    
    [[Page 66420]]
    
    stated that in the mining environment it would be difficult to 
    illuminate signs to the point they could be read and understood, and 
    that they would be difficult to maintain in most mining situations. 
    This commenter also believed that the nature of certain mining 
    operations does not lend itself to the use of signs because the work 
    area is constantly changing. Another commenter agreed, stating that 
    warning signs would be difficult to keep current in mobile operations.
        Warning signs could provide an indication to miners that they are 
    entering an area where the wearing of hearing protectors is required. 
    Some mine operators have voluntarily placed warning signs in high noise 
    areas such as preparation facilities and on surface mobile equipment.
        MSHA believes, due to the dynamic nature of mining (advancing 
    underground faces, changing quarry perimeters, a mobile workforce, 
    etc.), that a requirement for the installation of fixed warning signs 
    may be difficult to implement. Warning signs may also be inappropriate 
    where miners do not work a fixed period of time in the area covered by 
    the sign. For example, a miner in an area with a 90 dBA sound level for 
    less than four hours, with no significant noise exposure for the rest 
    of the day, would not be required to wear hearing protectors under 
    MSHA's proposal, whereas a miner who spends more than four hours in 
    that area would.
        After careful analysis of the literature and review of regulatory 
    requirements from international communities and the U.S. Armed 
    Services, MSHA believes that training may be a more appropriate vehicle 
    to inform workers of the hazards of noise to their hearing. Further, 
    the Agency believes that the posting of warning signs for noise should 
    be optional and left to the discretion of the mine operator. The 
    proposed rule would require initial and annual training for all miners 
    exposed above the action level as discussed under Sec. 62.130 Training 
    of this preamble.
        Though MSHA is not proposing to require warning signs for noise, it 
    expects that many mine operators will voluntarily post such signs to 
    indicate to miners locations where hearing protectors must be worn. If, 
    however, mine operators choose to use administrative controls to reduce 
    a miner's noise exposure, the proposal would require that the affected 
    miner be informed of the administrative procedures and that such 
    controls be posted on the mine bulletin board. Such procedures may 
    provide notification of sound levels in specific work locations.
    
    Section 62.125  Hearing Protectors.
    
        Whenever hearing protectors are required to be provided by the 
    proposed regulations, they must be provided in accordance with the 
    requirements of this section.
        The miner is to have a choice from at least one earplug type and 
    muff type protector; and, in the event dual hearing protection is 
    required, a choice of one of each. The mine operator is to ensure that 
    in those cases when hearing protection is required to be worn, it is 
    worn by miners exposed to sound levels required to be integrated into 
    the miner's dose measurement: i.e., sound levels above 80 dBA. The 
    hearing protector is to be fitted and maintained in accordance with the 
    manufacturer's instructions. Hearing protectors and necessary 
    replacements are to be provided by the mine operator at no cost to the 
    miner. Finally, should the hearing protector cause or aggravate a 
    medical pathology of the ear, the miner is to be allowed to select a 
    different hearing protector from among those offered by the mine 
    operator.
    Selection of Hearing Protector
        The proposal requires that if hearing protectors are required to be 
    provided to miners for any reasons, the mine operator shall provide a 
    choice of one earplug type and one muff type, and ensure proper fit. 
    Earmuffs include both active and passive; earplugs include disposable 
    earplugs, pre-molded earplugs, custom-molded earplugs, and canal caps. 
    The proposal also requires that the training in hearing protection 
    specified in proposed Sec. 62.130(a) be received at least once before 
    the miner has to make a choice: to ensure the miner understands the 
    choices available.
        While these requirements are limited, they will help to 
    significantly encourage hearing protector use and effectiveness. The 
    proposal does not seek to constrain mine operator selection of 
    protectors. As noted herein, hearing protectors come in a wide variety, 
    for different purposes, and with different attenuation values. MSHA 
    believes that mine operators have an incentive to provide a wide 
    variety of types to encourage safe and effective use.
        MSHA's existing noise standards require mine operators to provide 
    adequate hearing protectors, but do not specify that a variety of 
    hearing protectors be offered. OSHA's noise standard requires that 
    employees be given the opportunity to select from a variety of suitable 
    hearing protectors provided by the employer; however, the variety is 
    not defined. OSHA states in the 1981 preamble to its Hearing 
    Conservation Amendment (46 FR 4152) that ``The company must make a 
    concerted effort to find the right protector for each worker-one that 
    offers the appropriate amount of attenuation, is accepted in terms of 
    comfort, and is used by the employee.''
        In its ANPRM, MSHA asked whether mine operators should be required 
    to make available a selection of hearing protectors. Almost all of the 
    commenters on this issue were in favor of this provision. Some 
    specifically recommended that the mine operator provide a choice of at 
    least three different models, including at least one earmuff and one 
    earplug. One commenter suggested that the selection should include at 
    least six models. Most commenters indicated that the need to provide a 
    variety of hearing protectors is more related to fitting and comfort 
    than on the labeled attenuation per se.
        One commenter recommended against providing a variety of hearing 
    protectors, stating that ``It is the responsibility of the mine 
    operator to evaluate the various noise exposures, and to select the 
    appropriate HPDs [hearing protectors].'' The commenter maintained that 
    the mine operator should only have to provide an alternative hearing 
    protector when the individual has a specific condition which precludes 
    the use of the selected hearing protector.
        Several commenters addressed the need to allow the miner to choose 
    a hearing protector that is comfortable. One commenter stated that:
    
        The most effective hearing protector is one that is worn and 
    worn properly. If the hearing protector is not comfortable or the 
    employee cannot wear a certain type of plug or muff, then the 
    hearing protector will not be worn and the HCP will not be 
    effective.
    
    Another commenter maintained that ``* * * the principal usage problem 
    with HPD's is that because of discomfort, interference with necessary 
    communication, and interference with normal work routines, many HPD's 
    are not worn.'' While another commenter stated:
    
        The performance of hearing protectors in the field (including 
    the manners in which they are used, not used, or misused by workers 
    in situations in which HPDs are needed, but are uncomfortable, 
    unsafe, or otherwise inconvenient) is frequently inferior to their 
    performance when tested in idealized laboratory conditions and there 
    are substantial variations among individual susceptibilities to 
    noise-induced hearing loss [NIHL].
    
        The National Hearing Conservation Association's Task Force on 
    Hearing Protector Effectiveness (Royster, 1995)
    
    [[Page 66421]]
    
    recommends that the employer consider many criteria when selecting the 
    variety of hearing protectors from which workers are to choose. The 
    most important criterion for choosing a hearing protector is ``the 
    ability of a wearer to achieve a comfortable noise-blocking seal which 
    can be maintained during all noise exposures.'' Other criteria include 
    hearing protector's noise reduction, wearer's daily noise exposure, 
    variations in sound level during a work shift, user preference, 
    communication needs, hearing acuity of the wearer, compatibility with 
    other safety equipment, wearer's physical limitations, and climate and 
    working conditions. Physical limitations (missing fingers, arthritis, 
    limited hand strength) may restrict users from properly inserting 
    compressible foam earplugs in their ears.
        Berger (1986) stated that comfort must be considered when selecting 
    hearing protectors. If the laboratory attenuation of a hearing 
    protector is very high, but it is uncomfortable to wear, the actual in-
    use attenuation may be reduced or even nonexistent. Conversely, a 
    comfortable hearing protector with less attenuation may be worn 
    consistently, thereby providing greater effective protection.
        In EARLOG 8, Berger (1981) asserted that an employee should have 
    two weeks to try out an adequate hearing protector and select another 
    one if the original selection does not perform satisfactorily.
        In the report, Communication in Noisy Environments (Coleman et al., 
    1984), the authors stated that:
    
        Although acceptability is in part governed by the comfort of the 
    devices, there are other factors such as concern with hygiene, 
    belief in (real or presumed) communication difficulties, and social 
    constraints which can influence the extent to which workers will use 
    the protection provided. * * * Sweetland (1981) found concern about 
    communication difficulties to be a major factor in mine workers 
    acceptance of protectors.
    
    The authors further stated that:
    
        In general, ear inserts [earplugs] appear less attractive than 
    circumaural protectors [earmuffs] for mining conditions. A helmet 
    mounted circumaural protector is to be preferred on grounds of 
    comfort, ease of fitting and removal, reliability of attenuation, 
    and acceptability in terms of hygiene; whereas ear inserts of the 
    compressible foam type may produce marginally less interference with 
    communication and they will impair localization less, they are 
    likely to be more comfortable in hot and humid conditions.
    
        Pfeiffer (1992) suggested that greater care be exercised when 
    selecting hearing protectors for workers experiencing hearing loss. 
    Pfeiffer stated that it is important not to overprotect the worker 
    which can cause difficulty in communicating. If this happens, the 
    worker will be reluctant to wear the hearing protector.
        MSHA recognizes that local mine conditions such as dust, 
    temperature, and humidity can cause one type of hearing protector to be 
    more suitable than another. For example, under normal mining 
    conditions, some miners may experience problems with earmuffs because 
    of a buildup of perspiration under the seals.
        Based on such factors and on comments received in response to the 
    ANPRM, MSHA concluded that the minimum selection appropriate to offer 
    miners with normal hearing consists of at least one type of earmuff and 
    one type of earplug. MSHA expects that each hearing protector in the 
    selection would provide adequate attenuation. Further, a consensus of 
    the U.S. armed services and international communities agrees that 
    workers should choose from a selection of several hearing protectors.
        If miners are allowed to choose from a selection of hearing 
    protectors, particularly if given appropriate training as is required 
    under this proposal, they will be more apt to wear and care for them in 
    such a manner as to obtain the maximum amount of protection. Providing 
    miners with a choice from a selection of hearing protectors will foster 
    greater acceptance and use. Further, MSHA recognizes that a trial 
    period may be necessary for the miner to determine if using the 
    selected hearing protector for a prolonged period causes significant 
    discomfort. If significant discomfort occurs, MSHA encourages the mine 
    operator to allow the miner an opportunity to select an alternate 
    hearing protector. Selection of an alternative hearing protector is 
    mandatory under the proposal if required by a medical condition.
        There are several factors which the affected miner needs to 
    consider before choosing a hearing protector from the selection 
    offered, and which miners will learn about through the training 
    specified under proposed Sec. 62.130(a). These factors include--
        (1) Hearing protectors must fit properly to provide the estimated 
    amount of protection;
        (2) People have all shapes and sizes of ear canals, and fitting 
    commonly used earplugs to an unusually shaped ear canal may be 
    uncomfortable or harmful to the individual. For those earplugs which 
    need to be fitted to the size of the ear canal, all available sizes of 
    that earplug should be available for fitting and use. Some employees 
    may need a different size for each ear when their ear canals are of a 
    different size or configuration; and
        (3) Hearing impaired miners may need special hearing protectors 
    which provide adequate attenuation, yet permit auditory reception.
        With regard to the latter, MSHA is not at this time proposing that 
    any special type of hearing protector be provided, nor any type of 
    protector be excluded, for those miners who are already hearing 
    impaired. However, MSHA will endeavor to ensure operators understand 
    that special care should be taken in providing a hearing protector for 
    the safety of a miner with a significant hearing loss. Most earplugs 
    and earmuffs attenuate sound unequally across all frequencies and are 
    most effective at attenuating high frequency sounds. Hearing loss due 
    to noise and aging reaches its peak at the higher audiometric 
    frequencies. Because of these factors, a miner wearing a hearing 
    protector, without specific accommodation for any significant hearing 
    loss, would hear distorted auditory signals which would significantly 
    hamper communication. A miner, with a significant hearing loss and 
    wearing hearing protectors, could be placed in a hazardous situation 
    because he/she could not hear or comprehend an audible warning.
        Although some commenters have recommended the use of communication 
    type hearing protectors for hearing impaired miners, MSHA will caution 
    mine operators against their use in very high noise areas because the 
    sound level produced under the cup may be hazardous. Some manufacturers 
    of communication type hearing protectors, however, have placed limiters 
    in the electronics to protect against the speaker in the cup producing 
    hazardous sound levels.
        Even though some researchers have indicated that using a hearing 
    protector may cause communication problems for an impaired miner, 
    commenters have presented many practical ways of resolving this 
    problem. Consequently, MSHA chose not to propose specific requirements 
    regarding hearing protectors for impaired miners to allow the mine 
    operators maximum flexibility.
        MSHA solicits comments on whether mine operators should be required 
    to provide an additional type of hearing protector, such as flat 
    response, level dependent or active noise control earmuff, for miners 
    with a hearing impairment, or whether any type of protector should be 
    explicitly excluded for such miners.
    
    [[Page 66422]]
    
    Hearing Protector Effectiveness
        MSHA received many comments on the attenuation, or effectiveness, 
    of hearing protectors. The issue arises in a number of contexts, 
    including what role a hearing protector's attenuating characteristics 
    should play in the selection of the most appropriate hearing protector 
    in those cases requiring hearing protection.
        While MSHA recognizes the importance of proper selection, MSHA has 
    decided not to incorporate specific procedures into its proposal on 
    rating the effectiveness of hearing protectors. Based on the 
    information presented herein, MSHA has concluded there is not presently 
    a generally acceptable method of predicting hearing protector 
    attenuation in the field. Moreover, MSHA has determined that there are 
    other factors which are equally or more important than a hearing 
    protector's attenuation for ensuring that a miner is protected from 
    NIHL. These factors include: (1) comfort, (2) training, (3) fit, (4) 
    maintenance, and (5) consistent use.
        Nevertheless, MSHA realizes the merits of having a valid 
    methodology for determining the attenuation of hearing protectors--for 
    a variety of reasons, including facilitation of the selection of the 
    most appropriate hearing protector when selection and use is required. 
    The Agency, therefore, solicits comments on a scientifically based, yet 
    practical, method for determining the effectiveness of hearing 
    protectors as used under mining conditions. In addition, comments on 
    field estimates of hearing protector attenuation, especially the NIOSH 
    (1995) derating scheme, are encouraged.
        Current MSHA regulations do not explicitly address this issue. MSHA 
    policy, however, specifies a procedure for calculating a hearing 
    protector's effective attenuation based upon the Noise Reduction Rating 
    (NRR) provided by the manufacturer. Manufacturers currently determine 
    an NRR for each hearing protector from laboratory testing in accordance 
    with EPA regulations (40 CFR Sec. 211.206 and Sec. 211.207). The NRR is 
    intended to provide an estimate of the noise reduction achievable under 
    optimal conditions and was designed to be used with C-weighted sound 
    levels. Because MSHA measures noise exposure with A-weighting instead 
    of C-weighting, it adjusts the NRR by subtracting 7 dB. As reported by 
    Maraccini (1987), this 7-dB adjustment accounts for the average 
    difference between the C-weighted and A-weighted sound levels in 
    mining.
        OSHA's standard does specify the hearing protector attenuation 
    required. Under OSHA's standard, attenuation must be sufficient to 
    reduce an employee's noise exposure to a TWA8 of 90 dBA; except 
    that if the worker is experiencing an STS, then the hearing protector 
    must reduce the noise exposure to a TWA8 of 85 dBA. Employers are 
    required to use one of four methods to determine the noise exposure 
    beneath the hearing protector. These methods are NRR and NIOSH methods 
    1, 2, or 3 as described in the ``List of Personal Hearing Protectors 
    and Attenuation Data,'' HEW Publication No. 76-120, NIOSH 1975, pp. 21-
    37. The NRR is the most convenient method to use and is a 
    simplification of NIOSH method 2. In addition, when the NRR is to be 
    used with A-weighted sound levels, OSHA requires that 7 dB be 
    subtracted from the NRR.
        As noted in connection with the discussion of proposed 
    Sec. 62.120(c), where an employer wishes to take advantage of OSHA's 
    policy of not citing overexposures when, among other factors, adequate 
    hearing protection is being used, a more stringent method of 
    determining the effectiveness of hearing protectors is used by OSHA. In 
    evaluating hearing protector effectiveness in this context, OSHA also 
    subtracts 7 dB from the hearing protector's stated NRR to adjust for 
    the difference in weighting systems, but further derates the NRR by 
    50%. All types of hearing protectors are treated the same way. The 
    derating is done to account for the significant reductions, which 
    various researchers have found, in hearing protector attenuation under 
    industrial conditions when compared to laboratory conditions.
        One commenter to MSHA's ANPRM indicated that laboratory protocols 
    have been developed and are being tested which may be more 
    representative of the actual field performance of hearing protectors, 
    but noted that validated and agreed upon standardized procedures are 
    still some years away. This commenter stated:
    
        The real-world attenuation data which form the basis for our 
    criteria are taken from Berger's summary (1983) of 10 field studies, 
    utilizing 1551 employees, wearing seven different types of earplugs 
    and greater than nine different types of earmuffs, in over 50 
    different industries, and his more recent paper (Berger, 1988) which 
    discusses additional current studies. Although the data can be 
    separated by plugs and muffs, the variability within the plug 
    category is such that some of the better attenuating earplugs 
    overlap with the earmuffs. Therefore, for a general regulatory 
    guideline, the data averaged across all HPDs and employee subjects 
    is taken from the two papers. This results in an NRR84 of 
    approximately 10 dB (i.e., the NRR computed with a one-standard 
    deviation correction which estimates the protection at the 84th 
    percentile).
        Since the NRR is meant to be subtracted from the C-weighted 
    sound level, and the regulation is formulated in terms of A-weighted 
    levels, an indicator of representative C-A values for the mining 
    industry is then required. The 100 NIOSH noises (NIOSH, 1975) which 
    have often been taken to be representative of general industry have 
    median C-A of about 2 dB, and 90% have C-As of <6.5 db.="" however,="" mining="" noises="" may="" exhibit="" greater="" low-frequency="" energy.="" for="" example="" the="" data="" in="" kogut="" (1990)="" which="" represent="" 17="" different="" types="" of="" equipment="" in="" the="" metal/nonmetal="" mining="" industry="" (coal="" excluded),="" show="" a="" mean="" c-a="" of="" 6.7="" db,="" but="" the="" kogut="" values="" are="" not="" a="" statistically="" representative="" sample="" of="" the="" mining="" industry.="" for="" our="" purposes="" we="" will="" average="" the="" two="" estimates="" and="" presume="" a="" median="" c-a="" for="" mining="" of="" 5="" db.="" with="" an="" nrr="" for="" 84%="" of="" the="" users="" of="" 10="" db,="" and="" c-a="" value="" for="" typical="" mining="" noises="" of="" 5="" db,="" the="" credit="" for="" hpd="" attenuation="" for="" most="" of="" the="" users="" in="" the="" typical="" mining="" noises="" is="" 10-5="5" db.="" adding="" this="" value="" of="" 5="" db="" to="" the="" pel="" of="" 90="" dba="" sets="" the="" second="" cutoff="" level="" of="" 95="" dba.="" this="" commenter="" also="" stated="" that="" nrr's="" do="" not="" provide="" a="" good="" indication="" of="" either="" relative="" or="" absolute="" field="" performance;="" thus,="" ``there="" is="" no="" good="" way="" to="" accurately="" derate="" existing="" lab="" data="" to="" predict="" field="" performance.''="" in="" the="" niosh="" compendium="" of="" hearing="" protection="" devices="" (1994)="" several="" sets="" of="" laboratory="" measured="" attenuations,="" besides="" the="" nrr,="" are="" listed.="" these="" data="" were="" obtained="" using="" different="" standardized="" methods.="" niosh="" presents="" examples="" of="" using="" each="" method="" to="" estimate="" the="" sound="" level="" beneath="" the="" hearing="" protector.="" in="" addition,="" niosh="" presents="" physical="" features="" (i.e.,="" number="" of="" flanges,="" composition,="" compatibility="" with="" other="" personal="" safety="" equipment,="" etc.)="" of="" the="" hearing="" protectors.="" niosh="" (1995)="" recommends="" a="" derating="" scheme="" based="" upon="" the="" type="" of="" hearing="" protector.="" niosh="" acknowledges="" that="" hearing="" protector="" wearers="" do="" not="" attain="" the="" laboratory="" attenuation="" in="" industrial="" situations.="" accordingly,="" they="" recommend="" that="" to="" ascertain="" the="" effectiveness="" of="" a="" hearing="" protector="" in="" workplace="" use,="" the="" nrr="" for="" an="" earmuff,="" formable="" earplugs,="" and="" all="" other="" earplugs="" would="" be="" derated="" by="" 25%,="" 50%,="" and="" 70%,="" respectively.="" the="" national="" hearing="" conservation="" association's="" task="" force="" on="" hearing="" protector="" effectiveness="" (royster,="" 1995)="" recommends="" that="" the="" epa's="" nrr="" for="" hearing="" protector="" attenuation="" be="" replaced="" with="" a="" new="" nrr(sf),="" which="" the="" researchers="" felt="" more="" realistically="" reflects="" the="" field="" performance="" of="" hearing="" protectors.="" the="" nrr(sf)'s="" are="" determined="" by="" laboratory="" testing="" for="" hearing="" protector="" attenuation="" after="" the="" [[page="" 66423]]="" subject="" fits="" the="" hearing="" protector="" to="" his/her="" head.="" this="" differs="" from="" the="" epa's="" nrr="" value="" which="" is="" determined="" after="" the="" researcher="" fits="" the="" hearing="" protector="" to="" the="" subject.="" regardless="" of="" the="" method="" used,="" the="" amount="" of="" attenuation="" provided="" by="" a="" hearing="" protector="" will="" vary="" among="" the="" individual="" subjects="" resulting="" in="" a="" range="" of="" attenuation="" values.="" the="" task="" force="" stresses="" that="" it="" is="" not="" possible="" to="" predict="" the="" field="" attenuation="" of="" a="" given="" hearing="" protector="" for="" an="" individual;="" it="" concluded,="" however,="" that="" the="" nrr(sf)="" would="" be="" a="" more="" realistic="" estimate.="" in="" addition,="" small="" differences="" (less="" than="" 3="" db)="" in="" the="" nrr="" or="" nrr(sf)="" are="" not="" believed="" to="" be="" of="" practical="" consequence.="" the="" task="" force="" recommends="" continued="" audiometric="" testing="" whenever="" hearing="" protectors="" are="" used.="" msha="" notes="" that="" the="" american="" industrial="" hygiene="" association="" (aiha,="" 1995)="" recently="" sent="" the="" epa="" a="" letter="" requesting="" that="" the="" epa="" revise="" its="" rule="" on="" noise="" labeling="" requirements="" for="" hearing="" protectors.="" the="" reasons="" cited="" for="" requesting="" a="" revision="" of="" epa's="" nrr="" rating="" system="" included--="" (1)="" the="" current="" method="" of="" rating="" hearing="" protectors="" overestimates="" the="" actual="" workplace="" protection="" from="" 140="" to="" almost="" 2000="" percent;="" (2)="" the="" inability="" to="" predict="" absolute="" levels="" of="" protection="" from="" labeled="" values;="" (3)="" the="" labeled="" values="" are="" a="" poor="" predictor="" of="" relative="" performance="" of="" one="" hearing="" protector="" versus="" another;="" (4)="" there="" are="" no="" provisions="" for="" retesting="" the="" hearing="" protectors="" on="" a="" recurring="" basis;="" and="" (5)="" there="" is="" no="" requirement="" for="" quality="" assessment="" or="" accreditation="" of="" the="" test="" laboratory.="" michael="" (1991)="" believed="" that="" the="" simplification="" needed="" to="" obtain="" a="" single="" number="" rating="" (nrr)="" caused="" it="" to="" be="" inaccurate.="" instead="" of="" the="" nrr,="" the="" researcher="" recommended="" using="" the="" spectra="" of="" the="" noise="" in="" conjunction="" with="" the="" attenuation="" characteristics="" to="" select="" the="" most="" appropriate="" hearing="" protector.="" this="" is="" even="" more="" important="" when="" the="" wearer="" has="" sensorineural="" hearing="" loss.="" many="" field="" studies="" on="" the="" attenuation="" of="" hearing="" protectors="" have="" been="" conducted="" in="" the="" mining="" industry="" by="" giardino="" and="" durkt="" (1996),="" kogut="" and="" goff="" (1994),="" giardino="" and="" durkt="" (1994),="" bertrand="" and="" zeiden="" (1993),="" durkt="" (1993),="" goff="" et.="" al.="" (1986),="" durkt="" and="" marraccini="" (1986),="" goff="" and="" blank="" (1984),="" and="" savich="" (1979).="" with="" the="" exception="" of="" bertrand="" and="" zeiden="" (1993),="" these="" researchers="" reported="" that="" hearing="" protectors="" provided="" much="" less="" attenuation="" than="" that="" measured="" in="" the="" laboratory.="" some="" researchers="" tested="" new="" earmuffs="" while="" others="" tested="" old="" earmuffs.="" in="" many="" instances="" attenuation="" was="" minimal="" and="" highly="" variable.="" these="" studies="" indicate="" that="" hearing="" protector="" attenuation="" cannot="" be="" reliably="" predicted="" under="" actual="" use="" conditions="" and="" is="" substantially="" less="" than="" that="" indicated="" by="" the="" nrr="" from="" the="" manufacturer.="" bertrand="" and="" zeiden="" (1993)="" determined="" the="" effectiveness="" of="" hearing="" protectors="" by="" measuring="" the="" hearing="" level="" of="" miners="" exposed="" to="" sound="" levels="" exceeding="" 115="" dba.="" these="" researchers="" found="" that="" although="" the="" hearing="" protectors="" provided="" less="" attenuation,="" the="" difference="" was="" not="" significant.="" for="" example,="" miners="" exposed="" to="" 118="" dba="" had="" hearing="" levels="" consistent="" with="" exposure="" to="" 98="" dba.="" therefore,="" the="" hearing="" protector="" whose="" nrr="" was="" 24="" provided="" 20="" dba="" of="" attenuation.="" durkt="" (1993)="" studied="" the="" effectiveness="" of="" 11="" models="" of="" new="" earmuffs="" using="" miniature="" microphones="" inside="" and="" outside="" the="" cups.="" at="" surface="" mines,="" 107="" tests="" were="" conducted="" on="" operators="" of="" equipment,="" including="" bulldozers,="" front-end-loaders,="" and="" overburden="" drills.="" durkt="" concluded="" that="" the="" effectiveness="" of="" the="" earmuff="" was="" related="" to="" the="" noise="" spectrum.="" moreover,="" the="" measured="" noise="" reduction="" was="" much="" less="" than="" the="" nrr="" when="" the="" noise="" spectrum="" contained="" significant="" amounts="" of="" low="" frequency="" noise.="" most="" diesel-powered="" equipment="" generate="" noise="" which="" is="" primarily="" in="" the="" low="" frequency="" range.="" kogut="" and="" goff="" (1994)="" studied="" the="" effectiveness="" of="" earmuffs="" being="" used="" in="" both="" surface="" and="" underground="" mines.="" a="" total="" of="" 540="" tests="" were="" conducted="" on="" miners="" wearing="" their="" normal="" earmuffs.="" the="" procedure="" was="" similar,="" but="" not="" identical,="" to="" the="" procedure="" used="" by="" durkt="" (1993).="" like="" durkt,="" the="" researchers="" concluded="" the="" noise="" reduction="" afforded="" by="" earmuffs="" was="" related="" to="" the="" spectrum="" of="" the="" noise.="" according="" to="" the="" researchers,="" ``the="" earmuffs'="" effectiveness="" in="" reducing="" noise="" exhibited="" great="" variability="" and="" frequently="" fell="" far="" short="" of="" the="" nrr.''="" furthermore,="" a="" simple="" method="" of="" reliably="" predicting="" the="" effectiveness="" of="" earmuffs="" eluded="" the="" researchers.="" a="" complex="" method="" was="" developed="" for="" predicting="" the="" effectiveness="" of="" earmuffs;="" however,="" it="" lacks="" practicality.="" giardino="" and="" durkt="" (1996)="" and="" giardino="" and="" durkt="" (1994)="" expanded="" on="" the="" previous="" two="" discussed="" studies.="" a="" total="" of="" 1,265="" tests="" were="" performed="" on="" 545="" different="" machines="" (20="" different="" machine="" types).="" according="" to="" the="" researchers,="" earmuffs="" provided="" minimal="" noise="" reduction="" for="" the="" operators="" of="" equipment="" powered="" by="" internal="" combustion="" engines.="" the="" researchers="" concluded="" that="" the="" nrr="" was="" a="" poor="" predictor="" of="" earmuff="" performance="" under="" actual="" mining="" conditions.="" furthermore,="" they="" reported="" that="" the="" nrr="" is="" not="" a="" good="" indicator="" for="" comparing="" different="" models="" of="" earmuffs.="" numerous="" research="" studies="" performed="" in="" other="" industries="" by="" pfeiffer="" (1992),="" hempstock="" and="" hill="" (1990),="" green="" et="" al.="" (1989),="" behar="" (1985),="" lempert="" and="" edwards="" (1983),="" crawford="" and="" nozza="" (1981),="" and="" regan="" (1975)="" indicate="" that="" hearing="" protector="" effectiveness="" is="" substantially="" less="" than="" the="" nrr="" value="" indicated="" by="" the="" manufacturer.="" furthermore,="" regan="" (1975)="" found="" that="" earmuff="" type="" protectors="" yield="" the="" most="" attenuation="" and="" custom="" molded="" earplugs="" the="" least.="" behar="" (1985)="" found="" that="" the="" measured="" nrr,="" in="" industrial="" situations,="" averaged="" 14.9="" db="" lower="" and="" reached="" 25="" db="" lower="" than="" the="" manufacturer's="" nominal="" value.="" green="" et="" al.="" (1989)="" reported="" workers,="" who="" were="" using="" earplugs,="" were="" receiving="" one-third="" to="" one-half="" of="" the="" laboratory="" based="" nrr="" value="" and="" workers="" enrolled="" in="" an="" effective="" hcp="" obtain="" greater="" attenuation="" from="" their="" hearing="" protectors.="" crawford="" and="" nozza="" (1981)="" reported="" that="" the="" average="" attenuations="" of="" the="" earplugs="" were="" typically="" 50%="" of="" the="" manufacturer's="" values,="" except="" for="" user-molded="" earplugs="" whose="" field="" attenuation="" was="" near="" the="" laboratory="" values.="" lempert="" and="" edwards="" (1983)="" reported,="" ``in="" the="" majority="" of="" cases,="" workers="" received="" less="" than="" one-half="" of="" the="" potential="" attenuation="" of="" the="" earplugs''="" and="" concluded,="" ``regardless="" of="" the="" type="" of="" earplug="" used="" by="" a="" particular="" plant,="" a="" large="" portion="" of="" the="" workers="" received="" little="" or="" no="" attenuation.''="" hempstock="" and="" hill="" (1990)="" reported="" that="" the="" workplace="" performance="" of="" earmuffs="" more="" closely="" approximated="" the="" laboratory="" performance="" than="" earplugs.="" for="" both="" earmuffs="" and="" earplugs,="" the="" measured="" workplace="" attenuations="" were="" lower="" and="" the="" standard="" deviations="" higher="" than="" those="" measured="" in="" the="" laboratory.="" the="" researchers="" attributed="" these="" results="" to="" the="" ease="" of="" fitting="" an="" earmuff="" compared="" to="" fitting="" an="" earplug.="" their="" study="" revealed="" that="" the="" degradation="" was="" dependent="" upon="" the="" model="" of="" hearing="" protector="" and="" even="" differed="" between="" sites.="" another="" result="" was="" that="" safety="" glasses="" substantially="" degraded="" the="" performance="" of="" earmuffs.="" workers="" wearing="" safety="" glasses="" received="" approximately="" one-half="" of="" the="" laboratory="" attenuation.="" however,="" the="" researchers="" did="" not="" find="" that="" headband="" tension="" was="" a="" factor="" in="" the="" attenuation="" of="" earmuffs.="" royster="" et="" al.="" (1996)="" found="" that="" the="" wearing="" of="" safety="" glasses="" reduced="" the="" attenuation="" of="" earmuffs="" by="" about="" 5="" db="" at="" all="" frequencies.="" pfeiffer="" (1992)="" reported="" on="" studies="" of="" hearing="" protector="" effectiveness="" in="" [[page="" 66424]]="" german="" industry.="" according="" to="" pfeiffer="" earplugs="" provided="" between="" 10="" and="" 15="" db="" less="" attenuation="" and="" earmuffs="" about="" 6="" db="" less="" in="" industry="" than="" in="" the="" laboratory.="" as="" part="" of="" the="" study,="" used="" muffs,="" which="" were="" not="" obviously="" defective="" (e.g.,="" missing="" liners,="" headbands="" stretched="" out="" of="" shape,="" cushions="" missing="" or="" broken),="" were="" tested="" against="" new="" ones.="" the="" older="" earmuffs="" provided="" significantly="" less="" attenuation="" than="" new="" ones.="" the="" degradation="" of="" attenuation="" was="" dependent="" upon="" the="" model="" and="" frequency="" tested="" and="" exceeded="" 7="" db="" for="" some="" frequencies.="" abel="" and="" rokas="" (1986)="" reported="" that="" the="" attenuation="" of="" earplugs="" decreases="" as="" a="" function="" of="" wearing="" time="" and="" that="" head="" and="" jaw="" movement="" hastened="" the="" decrease.="" at="" noise-con="" 81,="" berger="" (1981)="" also="" concluded="" that="" the="" performance="" of="" hearing="" protectors="" decreased="" as="" a="" function="" of="" wearing="" time.="" kasden="" and="" d'aniello="" (1976,="" 1978)="" found="" that="" the="" custom="" molded="" earplugs="" retained="" their="" attenuation="" after="" three="" hours="" of="" use="" during="" normal="" activity;="" however,="" typical="" earplug="" performance="" degraded="" over="" the="" three="" hours="" of="" use.="" krutt="" and="" mazor="" (1980)="" reported="" that="" the="" attenuation="" of="" mineral="" down="" earplugs="" decreased="" over="" a="" three-hour="" wearing="" period.="" these="" researchers="" did="" not="" observe="" any="" degradation="" of="" the="" attenuation="" of="" expandable="" foam="" earplugs.="" cluff="" (1989)="" investigated="" the="" effect="" of="" jaw="" movement="" on="" the="" attenuation="" provided="" by="" earplugs="" and,="" determined="" the="" change="" in="" attenuation="" was="" dependent="" on="" type="" of="" earplug.="" the="" self-expanding="" viscose="" foam="" earplugs="" retained="" more="" of="" their="" attenuation="" than="" multi-flanged="" or="" glass-fiber="" earplugs.="" casali="" and="" grenell="" (1989)="" tested="" the="" effect="" of="" activity="" on="" the="" attenuation="" provided="" by="" an="" earmuff="" and="" found="" that="" only="" at="" 125="" hz="" was="" there="" a="" significant="" degradation="" in="" attenuation.="" furthermore,="" the="" attenuation="" of="" an="" earmuff="" was="" highly="" dependent="" upon="" the="" fit.="" royster="" and="" royster="" (1990)="" report="" that="" the="" noise="" reduction="" rating="" (nrr)="" cannot="" be="" used="" to="" determine,="" or="" rank="" order,="" the="" real="" world="" attenuation="" of="" hearing="" protectors.="" two="" individuals,="" using="" the="" same="" model="" of="" hearing="" protector,="" can="" obtain="" vastly="" different="" levels="" of="" attenuation.="" royster="" and="" royster="" stated="" that="" ``products="" that="" are="" more="" goof-proof="" (earmuffs="" and="" foam="" earplugs)="" provided="" higher="" real-world="" attenuation="" than="" other="" hpds.''="" casali="" and="" park="" (1992)="" reported="" that="" the="" noise="" attenuation="" at="" 500="" or="" 1000="" hz="" showed="" a="" high="" correlation="" with="" the="" total="" noise="" attenuation="" of="" hearing="" protectors.="" therefore,="" the="" researchers="" believe="" that="" models="" can="" be="" developed="" to="" predict="" the="" total="" attenuation="" of="" hearing="" protectors="" based="" upon="" the="" measured="" attenuation="" at="" a="" single="" frequency.="" this="" would="" eliminate="" the="" need="" to="" derate="" the="" nrr="" so="" that="" it="" accurately="" reflects="" the="" field="" attenuation.="" the="" prediction="" method,="" they="" believe,="" will="" provide="" information="" on="" the="" adequacy="" of="" the="" worn="" hearing="" protector="" and="" can="" be="" used="" in="" objectively="" fitting="" the="" hearing="" protector.="" berger="" (1992)="" reported="" on="" the="" progress="" of="" the="" ansi="" working="" group="" s12/wg11,="" ``field="" effectiveness="" and="" physical="" characteristics="" of="" hearing="" protectors'',="" on="" developing="" or="" identifying="" laboratory="" and/or="" field="" procedure(s)="" which="" yield="" useful="" estimates="" of="" field="" performance="" of="" hearing="" protectors.="" the="" working="" group="" was="" established="" to="" address="" the="" clearly="" demonstrable="" divergence="" between="" laboratory="" and="" field="" attenuations="" of="" hearing="" protectors.="" berger="" also="" summarized="" the="" results="" of="" 16="" studies="" involving="" over="" 2,600="" subjects="" on="" the="" field="" attenuation="" of="" hearing="" protectors.="" earplug="" attenuation="" averaged="" about="" 25%="" of="" the="" published="" u.s.="" laboratory="" attenuations="" (range="" 6="" to="" 52%)="" and="" earmuff="" attenuations="" averaged="" about="" 60%="" of="" the="" laboratory="" attenuations="" (range="" 33="" to="" 74%).="" royster="" et="" al="" (1996)="" reported="" on="" the="" progress="" of="" the="" american="" national="" standards="" institute="" working="" group="" (s12/wg11)="" charged="" with="" developing="" a="" laboratory="" methodology="" of="" rating="" hearing="" protectors="" which="" reflects="" the="" attenuation="" obtained="" by="" workers.="" hearing="" protector="" attenuation="" measured="" using="" this="" methodology="" reflects="" the="" attenuation="" achieved="" by="" workers="" in="" a="" well="" managed="" hearing="" conservation="" program.="" the="" working="" group="" has="" developed="" a="" methodology="" and="" is="" in="" the="" process="" of="" drafting="" an="" ansi="" standard="" around="" it.="" however,="" it="" will="" be="" some="" time="" before="" the="" standard="" is="" adopted.="" even="" if="" the="" standard="" is="" adopted,="" there="" will="" be="" some="" legal="" ramifications,="" as="" the="" epa="" would="" have="" to="" append="" their="" regulations="" to="" adopt="" this="" standard="" as="" the="" method="" for="" rating="" hearing="" protectors.="" as="" part="" of="" the="" testing="" of="" the="" methodology,="" the="" researchers="" found="" that="" the="" instructions="" which="" manufacturers="" include="" with="" their="" hearing="" protectors="" may="" be="" inadequate.="" some="" of="" the="" test="" subjects="" could="" not="" properly="" don="" the="" earplug,="" from="" simply="" reading="" the="" manufacturer's="" instructions.="" as="" demonstrated="" above,="" many="" researchers="" have="" developed="" standardized="" methods="" of="" measuring="" the="" attenuation="" of="" hearing="" protectors="" in="" a="" laboratory="" setting.="" in="" addition,="" many="" researchers="" have="" compared="" the="" results="" of="" laboratory="" attenuations="" to="" estimated="" or="" measured="" field="" attenuations.="" however,="" based="" on="" a="" review="" of="" the="" major="" studies,="" msha="" notes="" that="" researchers="" have="" yet="" to="" develop="" standardized="" tests="" for="" measuring="" the="" field="" attenuation="" of="" hearing="" protectors.="" msha="" is="" cognizant="" of="" the="" potential="" for="" increased="" use="" of="" diesel="" equipment="" in="" mines="" in="" coming="" years.="" diesel="" engine="" noise,="" a="" common="" mining="" noise="" control="" problem,="" is="" predominantly="" low="" frequency="" noise.="" in="" this="" regard,="" the="" agency="" notes="" that="" hearing="" protectors="" are="" generally="" more="" effective="" in="" reducing="" high="" frequency="" noise="" than="" low="" frequency="" noise.="" thus,="" noise="" from="" diesel="" engines="" contains="" the="" frequencies="" where="" hearing="" protectors="" are="" least="" able="" to="" attenuate="" the="" noise.="" the="" consequence="" is="" that="" hearing="" protectors="" poorly="" protect="" workers="" from="" excessive="" noise="" exposure="" when="" the="" source="" of="" the="" noise="" is="" a="" diesel="" engine.="" some="" special="" hearing="" protectors,="" notably="" flat="" response="" hearing="" protectors,="" attenuate="" the="" sound="" across="" all="" frequencies="" the="" same.="" in="" developing="" a="" flat="" response="" hearing="" protector,="" the="" manufacturer="" degraded="" the="" attenuation="" at="" the="" high="" frequency="" instead="" of="" enhancing="" the="" low="" frequency="" attenuation.="" msha="" has="" concluded="" that="" at="" this="" time="" there="" is="" not="" a="" consensus="" among="" the="" scientific="" community="" as="" to="" a="" reliable="" method="" of="" predicting="" the="" actual="" attenuation="" received="" from="" hearing="" protectors="" in="" the="" mining="" environment.="" additionally,="" experience="" indicates="" that="" miners="" do="" not="" receive="" the="" full="" attenuation="" measured="" in="" the="" laboratory="" (nrr).="" research="" data="" indicate="" that="" many="" workers="" receive="" only="" a="" small="" fraction="" of="" the="" nrr.="" therefore,="" the="" agency="" has="" determined="" that="" one="" cannot="" rely="" solely="" on="" the="" epa's="" nrr="" value.="" because="" of="" the="" lack="" of="" an="" acceptable="" method="" of="" predicting="" hearing="" protector="" attenuation="" in="" the="" field,="" msha="" chose="" not="" to="" include="" a="" method="" for="" determining="" the="" adequacy="" of="" hearing="" protectors="" in="" the="" proposed="" noise="" regulations.="" it="" should="" be="" noted="" that="" in="" order="" to="" ensure="" hearing="" protection="" devices="" have="" undergone="" testing="" to="" ensure="" quality,="" msha="" is="" proposing="" that="" the="" definition="" of="" ``hearing="" protector''="" permit="" only="" devices="" having="" a="" ``scientifically="" accepted="" indicator="" of="" noise="" reduction="" value.''="" the="" agency="" solicits="" comments="" as="" to="" alternatives="" to="" the="" nrr="" that="" could="" be="" used="" in="" this="" regard.="" wearing="" of="" hearing="" protectors="" proposed="" sec.="" 62.120="" would="" require="" that="" hearing="" protectors="" must="" be="" worn="" in="" certain="" cases:="" if="" noise="" exceeds="" the="" action="" level="" and="" a="" baseline="" audiogram="" has="" not="" taken="" place="" within="" 6="" months="" after="" the="" exposure="" is="" determined;="" if="" an="" sts="" has="" been="" detected;="" and="" whenever="" a="" miner="" is="" [[page="" 66425]]="" exposed="" to="" noise="" levels="" above="" the="" pel.="" in="" such="" cases,="" proposed="" sec.="" 62.125="" would="" provide="" that="" the="" hearing="" protectors="" must="" be="" worn="" when="" the="" miner="" is="" ``exposed="" to="" sound="" levels="" which="" are="" required="" to="" be="" integrated="" into="" a="" miner's="" noise="" exposure="" measurement.''="" this="" means="" that="" if="" a="" miner="" is="" required="" to="" wear="" hearing="" protectors,="" those="" protectors="" must="" be="" worn="" when="" that="" miner="" is="" exposed="" to="" sound="" levels="" above="" 80="" dba;="" sounds="" above="" that="" level="" have="" been="" demonstrated="" to="" be="" harmful,="" while="" such="" a="" demonstration="" has="" not="" been="" made="" for="" sound="" levels="" less="" than="" 80="" dba.="" msha="" recognizes="" that="" mine="" operators="" may="" want="" to="" develop="" particular="" policies="" on="" exactly="" when="" hearing="" protectors="" can="" be="" removed,="" and="" sees="" no="" need="" to="" delimit="" how="" this="" might="" be="" done.="" this="" practical="" approach,="" when="" taken="" together="" with="" the="" proposed="" requirements="" for="" employee="" training="" about="" hearing="" protectors="" and="" ensuring="" selection="" and="" proper="" fit="" of="" hearing="" protectors="" should="" facilitate="" the="" appropriate="" use="" of="" hearing="" protectors.="" both="" msha's="" and="" osha's="" existing="" standards="" require="" that="" hearing="" protectors="" be="" worn="" when="" the="" employee's="" noise="" dose="" exceeds="" permissible="" levels.="" neither="" standard,="" however,="" specifies="" a="" sound="" level="" below="" which="" workers="" could="" remove="" their="" hearing="" protectors.="" although="" msha="" received="" general="" comments="" on="" levels="" above="" which="" hearing="" protectors="" should="" be="" worn,="" msha="" did="" not="" receive="" any="" specific="" comments="" addressing="" wearing="" practices="" or="" under="" what="" conditions="" it="" would="" be="" safe="" to="" remove="" a="" hearing="" protector.="" as="" has="" been="" emphasized,="" hearing="" protectors="" are="" only="" effective="" if="" they="" are="" worn.="" chart="" nr1="" illustrates="" that="" the="" amount="" of="" attenuation="" provided="" is="" highly="" dependent="" upon="" the="" duration="" a="" hearing="" protector="" is="" worn.="" billing="" code="" 4510-43-p="" [graphic]="" [tiff="" omitted]="" tp17de96.008="" chart="" nr1="" demonstrates="" that="" if="" a="" hearing="" protector="" with="" an="" nrr="" of="" 29="" db="" is="" worn="" only="" half="" the="" time,="" the="" wearer="" will="" effectively="" obtain="" only="" about="" 5="" db="" of="" attenuation.="" thus,="" it="" is="" critical="" for="" mine="" operators="" to="" ensure="" that="" the="" hearing="" protectors="" provided="" are="" worn.="" an="" nrr="" of="" 29="" db="" is="" among="" the="" highest="" nrr="" values="" reported="" by="" hearing="" protector="" manufacturers.="" although="" msha="" did="" not="" ask="" a="" specific="" question="" in="" its="" anprm="" on="" monitoring="" effective="" usage="" of="" hearing="" protectors,="" several="" commenters="" recommended="" that="" msha="" require="" mine="" operators="" to="" supervise="" the="" proper="" wearing="" of="" hearing="" protectors.="" despite="" mandatory="" use="" of="" hearing="" protectors,="" most="" workers="" in="" the="" abel="" (1986)="" study="" admitted="" to="" wearing="" their="" hearing="" protectors="" less="" than="" 50%="" of="" the="" time.="" further,="" many="" modified="" their="" hearing="" protectors="" to="" provide="" greater="" comfort.="" many="" of="" the="" modifications="" had="" a="" deleterious="" effect="" on="" the="" attenuation.="" in="" earlog="" 8,="" berger="" (1981)="" contends="" that="" persons,="" who="" are="" more="" prone="" to="" otitis="" externa="" (infections),="" would="" need="" to="" be="" monitored="" more="" closely="" for="" failure="" to="" wear="" their="" hearing="" protectors.="" persons="" with="" a="" medical="" pathology="" of="" the="" ear="" are="" more="" likely="" to="" resist="" wearing="" a="" hearing="" protector="" because="" of="" pain="" or="" extreme="" discomfort="" associated="" with="" its="" use.="" based="" on="" the="" comments="" received="" and="" msha's="" experience,="" one="" critical="" factor="" impacting="" on="" miner="" use="" is="" their="" concern="" that="" wearing="" hearing="" protectors="" can,="" under="" some="" circumstances,="" create="" serious="" safety="" risks.="" apart="" from="" the="" information="" previously="" noted="" in="" connection="" with="" the="" discussion="" of="" the="" proper="" selection="" of="" a="" hearing="" protector="" by="" miners="" already="" suffering="" hearing="" loss,="" there="" is="" the="" issue="" whether="" hearing="" protectors="" diminish="" the="" ability="" of="" even="" miners="" with="" good="" hearing="" to="" hear="" ``roof="" talk.''="" prout="" et="" al.="" (1973)="" stated="" that:="" personal="" ear="" protectors="" do="" not="" generally="" prevent="" a="" miner="" from="" hearing="" and="" analyzing="" roof="" talk="" when="" the="" noise="" level="" [sound="" level]="" is="" sufficiently="" high="" as="" to="" require="" the="" use="" of="" ear="" protectors.="" however,="" the="" ability="" to="" interpret="" roof="" warning="" signals="" is="" degraded="" by="" the="" use="" of="" ear="" protectors="" in="" quiet.="" consequently,="" ear="" protectors="" should="" be="" removed="" when="" the="" noisy="" machines="" are="" shut="" down.="" msha="" is="" reviewing="" its="" own="" records="" for="" further="" information="" on="" the="" effect="" of="" hearing="" protectors="" on="" safety,="" and="" welcomes="" further="" information="" from="" commenters.="" of="" course,="" msha="" recognizes="" that="" failure="" to="" wear="" hearing="" protectors="" may="" accomplish="" nothing="" in="" some="" cases.="" for="" example,="" if="" some="" surface="" haulage="" fatal="" accidents="" result="" because="" high="" sound="" levels="" from="" mining="" machinery="" mask="" the="" backup="" alarms,="" taking="" off="" hearing="" protectors="" is="" not="" going="" to="" make="" the="" working="" environment="" any="" safer.="" indeed="" it="" is="" more="" likely="" that="" the="" miner="" would="" suffer="" a="" temporary="" threshold="" shift="" which="" would="" make="" it="" [[page="" 66426]]="" even="" more="" likely="" the="" backup="" alarm="" was="" missed.="" msha's="" review="" of="" the="" literature="" and="" codes="" revealed="" that="" the="" u.s.="" armed="" services="" and="" many="" international="" communities="" have="" specified="" sound="" levels="" above="" which="" hearing="" protectors="" must="" be="" worn.="" msha="" believes="" proposing="" specific="" trigger="" levels="" for="" hearing="" protectors="" in="" specific="" circumstances="" would="" be="" burdensome="" and="" require="" mine="" operators="" to="" conduct="" a="" comprehensive="" survey="" on="" each="" piece="" of="" equipment.="" a="" more="" practical="" approach="" would="" be="" for="" mine="" operators="" to="" ensure="" through="" their="" policies="" that="" hearing="" protectors="" are="" worn="" whenever="" noise="" producing="" equipment="" is="" operating="" in="" the="" miner's="" work="" area,="" and="" permit="" miners="" to="" remove="" their="" hearing="" protectors="" in="" areas="" with="" low="" sound="" levels="" (below="" 80="" dba).="" this="" would="" minimize="" the="" miner's="" feeling="" of="" isolation="" and="" communication="" difficulties="" caused="" by="" the="" wearing="" of="" hearing="" protectors="" in="" such="" areas.="" as="" previously="" presented,="" most="" researchers="" have="" indicated="" that="" sound="" levels="" below="" 80="" dba="" are="" not="" hazardous.="" the="" agency,="" however,="" requests="" additional="" comment="" on="" this="" issue,="" and,="" as="" noted="" above,="" on="" the="" specific="" issue="" of="" whether="" hearing="" protection="" can="" be="" a="" safety="" hazard.="" fitting="" of="" hearing="" protectors="" the="" proposal="" would="" require="" that="" mine="" operators="" ensure="" that="" hearing="" protectors="" be="" fitted="" in="" accordance="" with="" manufacturer's="" instructions.="" msha's="" existing="" noise="" standards="" do="" not="" address="" requirements="" for="" fitting="" hearing="" protectors.="" osha's="" existing="" standards="" require="" that="" employers="" ensure="" proper="" initial="" fitting="" and="" supervise="" the="" correct="" use="" of="" all="" hearing="" protectors.="" many="" commenters="" on="" this="" issue="" recommended="" fitting.="" most="" of="" these="" specified="" use="" of="" the="" manufacturer's="" instructions="" for="" fitting.="" a="" few="" of="" these="" specifically="" recommended="" that="" miners="" be="" fitted="" by="" individuals="" trained="" in="" the="" fitting="" of="" hearing="" protectors.="" other="" commenters="" did="" not="" recommend="" fitting="" per="" se,="" but="" recommended="" that="" mine="" operators="" provide="" a="" variety="" of="" types="" and="" sizes="" of="" hearing="" protectors="" to="" ensure="" proper="" fit.="" several="" commenters="" indicated="" that="" some="" types="" of="" hearing="" protectors="" do="" not="" require="" fitting.="" one="" commenter="" recommended="" use="" of="" audiometric="" data="" base="" analysis="" (adba)="" to="" determine="" hearing="" protector="" effectiveness.="" other="" than="" adba,="" this="" commenter="" believed="" that="" there="" was="" insufficient="" data="" at="" this="" time="" to="" recommend="" a="" criterion="" for="" proper="" fitting.="" in="" earlog="" 17,="" berger="" (1985)="" recommends="" that="" ``prior="" to="" issuing="" hpds="" the="" fitter="" should="" visually="" examine="" the="" external="" ear="" to="" identify="" any="" medical="" or="" anatomical="" conditions="" which="" might="" interfere="" with="" or="" be="" aggravated="" by="" the="" use="" of="" the="" protector="" in="" question.''="" in="" communication="" in="" noisy="" environments,="" coleman="" et="" al.="" (1984)="" stated:="" if="" a="" protector="" cannot="" be="" removed="" or="" fitted="" easily="" and="" quickly,="" it="" may="" be="" either="" left="" on="" when="" not="" needed,="" possibly="" impairing="" communication="" *="" *="" *="" or="" not="" fitted="" when="" needed,="" reducing="" the="" protection="" from="" noise="" exposure.="" ease="" of="" fitting="" is="" therefore="" a="" desirable="" attribute="" for="" coal="" mining="" conditions.="" sweetland="" (1981)="" found="" that="" circumaural="" protectors="" were="" removed="" and="" replaced="" more="" often="" than="" earplugs="" in="" mining="" conditions,="" which="" could="" be="" taken="" as="" an="" indication="" that="" the="" former="" devices="" were="" easier="" to="" fit="" and="" use.="" *="" *="" *="" factors,="" such="" as="" the="" time="" required="" to="" hold="" a="" compressible="" foam="" plug="" in="" position="" for="" it="" to="" achieve="" its="" design="" performance,="" and="" the="" procedure="" required="" to="" fit="" inserts="" correctly,="" which="" involves="" reaching="" around="" the="" back="" of="" the="" head="" to="" grasp="" the="" earlobe,="" can="" reduce="" their="" acceptability="" for="" mining="" conditions.="" at="" noise-con="" 81,="" berger="" (1981)="" reported="" that="" the="" attenuation="" was="" greater="" when="" noise="" was="" used="" to="" help="" in="" the="" fitting="" of="" hearing="" protectors="" although="" the="" variability="" was="" not="" significantly="" greater.="" carter="" and="" upfold="" (1993)="" investigated="" methods="" of="" determining="" the="" attenuation="" provided="" by="" foam="" earplugs.="" both="" an="" earmuff="" with="" an="" earphone="" and="" a="" cushion="" with="" an="" earphone="" gave="" results="" comparable="" to="" the="" standard="" laboratory="" method="" and="" could="" be="" used="" to="" estimate="" the="" group="" attenuation="" of="" foam="" earplugs.="" however,="" the="" results="" of="" the="" measured="" attenuation="" for="" individuals="" were="" not="" as="" good="" as="" that="" for="" the="" group.="" the="" researchers,="" therefore,="" concluded="" that="" neither="" method="" with="" earmuffs="" or="" cushions="" could="" be="" used="" to="" determine="" the="" attenuation="" provided="" by="" a="" foam="" earplug="" to="" an="" individual,="" although="" the="" methods="" could="" be="" used="" to="" check="" the="" effectiveness="" of="" fitting="" and="" training="" of="" a="" group.="" merry="" et="" al.="" (1992)="" reported="" that="" subjects="" obtained="" greater="" attenuation="" from="" earplugs="" if="" an="" experimenter="" directs="" the="" fitting="" using="" the="" subject's="" response="" to="" noise="" when="" compared="" to="" subjects="" simply="" reading="" the="" manufacturer's="" instructions="" and="" inserting="" their="" own="" earplugs.="" chung="" et="" al.="" (1983)="" reported="" that="" the="" major="" factor="" affecting="" the="" earmuff="" performance="" was="" the="" fit="" which="" is="" dependent="" upon="" headband="" tension.="" adequate="" tension="" is="" necessary="" for="" good="" attenuation.="" however,="" high="" headband="" tension="" generally="" caused="" discomfort.="" the="" same="" occurred="" when="" the="" earmuff="" seal="" was="" cracked.="" however,="" no="" effect="" of="" the="" age="" of="" the="" earmuffs="" was="" observed.="" chung="" et="" al.="" concluded="" that="" training="" and="" proper="" fitting="" can="" increase="" the="" effectiveness="" of="" earmuffs,="" thus="" protecting="" workers="" from="" incurring="" noise-induced="" hearing="" loss="" (nihl).="" phoon="" and="" lee="" (1993)="" studied="" workers="" who="" developed="" nihl="" in="" singapore.="" for="" 103="" of="" 156="" earplug="" users="" (66%)="" who="" developed="" nihl,="" there="" was="" a="" mismatch="" between="" the="" earplug="" and="" the="" size="" of="" both="" ear="" canals.="" in="" 13.5%="" of="" these="" workers,="" the="" mismatch="" occurred="" in="" one="" ear.="" royster="" et="" al.="" (1996)="" reported="" the="" manufacturer's="" instructions="" were="" not="" always="" adequate="" in="" describing="" the="" procedures="" for="" donning="" a="" hearing="" protector.="" several="" subjects="" improperly="" inserted="" earplugs="" during="" a="" laboratory="" experiment="" of="" hearing="" protector="" attenuation.="" the="" inappropriately="" inserted="" earplugs="" would="" be="" considered="" improperly="" fitted="" hearing="" protectors.="" ansi="" s3.19-1974,="" ``method="" for="" the="" measurement="" of="" real-ear="" protection="" of="" hearing="" protectors="" and="" physical="" attenuation="" of="" earmuffs'',="" recommends="" that="" 60="" to="" 70="" db="" white="" noise="" be="" used="" when="" the="" subject="" fits="" a="" hearing="" protector.="" white="" noise="" has="" essentially="" a="" random="" spectrum="" with="" equal="" energy="" per="" unit="" frequency="" bandwidth="" over="" a="" specified="" bandwidth.="" as="" described="" above,="" researchers="" have="" identified="" several="" techniques="" for="" both="" subjectively="" and="" objectively="" evaluating="" the="" fit="" of="" hearing="" protectors.="" while="" many="" of="" the="" techniques="" show="" promise,="" there="" is="" no="" consensus="" as="" to="" which="" method="" is="" best.="" most="" techniques="" are="" applicable="" to="" a="" specific="" type="" of="" hearing="" protector="" and="" are="" not="" practical="" for="" use="" by="" many="" mine="" operators.="" these="" techniques="" are="" discussed="" further="" under="" the="" hearing="" protector="" effectiveness="" section="" of="" this="" preamble.="" msha="" also="" considered="" the="" use="" of="" adba="" (audiometric="" data="" base="" analysis)="" to="" determine="" the="" effectiveness="" of="" hearing="" protectors="" in="" lieu="" of="" subjective="" fitting="" requirements.="" since="" adba="" does="" not="" provide="" immediate="" feedback="" as="" to="" the="" fit="" of="" a="" hearing="" protector,="" msha="" has="" concluded="" that="" adba="" is="" inappropriate="" for="" determining="" the="" fit="" of="" a="" hearing="" protector.="" adba="" analysis="" requires="" multiple="" subjects,="" not="" an="" individual,="" before="" a="" conclusion="" of="" adequacy="" is="" determined.="" besides="" adba="" determines="" the="" adequacy="" of="" the="" hcp="" (protecting="" the="" hearing="" acuity="" of="" a="" group="" of="" workers),="" not="" the="" adequacy="" of="" protecting="" an="" individual.="" moreover,="" msha="" believes="" that="" adba="" is="" not="" practical="" for="" most="" mining="" operations="" as="" discussed="" under="" the="" evaluation="" of="" hcp="" effectiveness="" section="" of="" this="" preamble.="" furthermore,="" adba="" requires="" several="" audiograms="" which="" are="" conducted="" on="" an="" [[page="" 66427]]="" annual="" basis.="" in="" the="" interim,="" the="" hearing="" acuity="" of="" a="" miner="" could="" be="" irreversibly="" damaged.="" as="" supported="" by="" the="" researchers="" and="" many="" commenters,="" msha="" agrees="" that="" proper="" fitting="" is="" necessary="" to="" ensure="" optimal="" effectiveness="" of="" hearing="" protectors="" and="" that="" it="" should="" not="" be="" left="" solely="" up="" to="" the="" individual="" miner="" to="" determine="" if="" the="" hearing="" protector="" fits="" properly.="" further,="" msha="" is="" concerned="" that="" some="" manufacturer's="" instructions="" are="" not="" adequate="" to="" ensure="" the="" proper="" fitting="" of="" a="" hearing="" protector.="" although="" comfortable="" hearing="" protectors="" should="" be="" provided,="" msha="" is="" also="" concerned="" that="" some="" miners="" may="" choose="" hearing="" protectors="" that="" are="" too="" loose="" or="" otherwise="" improperly="" fit,="" and="" consequently="" not="" achieve="" adequate="" noise="" reduction.="" in="" light="" of="" the="" wide="" variety="" of="" hearing="" protectors="" available,="" the="" broad="" range="" of="" subjective="" fitting="" procedures,="" and="" the="" lack="" of="" consensus="" on="" an="" objective="" fitting="" method,="" msha="" concluded="" that="" the="" manufacturer's="" instructions="" are="" the="" best="" criteria="" for="" fitting.="" msha="" encourages="" commenters="" to="" provide="" information="" on="" any="" standardized="" methods="" of="" testing="" the="" fit="" of="" hearing="" protectors.="" maintenance="" of="" hearing="" protectors="" msha's="" proposal="" would="" also="" require="" mine="" operators="" to="" ensure="" that="" hearing="" protectors="" are="" maintained="" in="" accordance="" with="" manufacturer's="" instructions.="" neither="" msha's="" nor="" osha's="" existing="" noise="" standards="" address="" requirements="" for="" maintaining="" hearing="" protectors.="" msha="" recognizes="" that="" it="" is="" difficult="" to="" keep="" hearing="" protectors="" clean="" in="" the="" mining="" environment.="" using="" contaminated="" hearing="" protectors,="" however,="" may="" contribute="" to="" a="" medical="" pathology="" of="" the="" ear.="" once="" the="" skin="" has="" been="" abraded="" or="" inflamed,="" it="" is="" easier="" for="" microorganisms="" normally="" found="" in="" the="" ear="" to="" invade="" the="" skin.="" when="" hearing="" protectors="" are="" implicated="" as="" the="" cause="" of="" inflammation="" of="" the="" external="" ear="" canal="" (otitis="" externa),="" often="" the="" hearing="" protector="" is="" contaminated="" with="" an="" irritating="" or="" abrasive="" substance.="" this="" situation="" can="" be="" corrected="" with="" proper="" cleaning="" of="" the="" hearing="" protector="" before="" use.="" msha's="" proposal="" is="" designed="" to="" ensure="" that="" miners="" not="" develop="" medical="" problems="" while="" they="" are="" attempting="" to="" protect="" themselves="" from="" the="" hazard="" of="" noise.="" if="" an="" earplug="" cannot="" be="" adequately="" cleaned,="" then="" the="" mine="" operator="" would="" have="" to="" replace="" it.="" in="" addition="" to="" providing="" guidance="" on="" the="" fitting="" of="" hearing="" protectors,="" manufacturers="" also="" provide="" instructions="" on="" the="" proper="" care="" and="" cleaning="" of="" their="" hearing="" protectors.="" many="" recommend="" soap,="" warm="" water,="" and="" careful="" rinsing.="" solvents="" and="" disinfectants="" generally="" are="" discouraged="" as="" cleaning="" agents="" because="" they="" can="" cause="" skin="" irritation="" and="" some="" can="" damage="" the="" hearing="" protector.="" in="" most="" cases,="" the="" proper="" insertion="" technique="" for="" earplugs="" would="" just="" be="" a="" matter="" of="" applying="" common="" sense,="" i.e.,="" cleaning="" the="" hands="" before="" rolling="" and/or="" inserting="" earplugs.="" several="" commenters="" addressed="" hygiene="" problems="" when="" the="" hearing="" protectors="" become="" dirty.="" one="" of="" these="" commenters="" stated="" that="" miners="" would="" need="" to="" clean="" their="" permanent="" hearing="" protector="" daily="" and="" that="" irritation="" due="" to="" sweating="" and="" skin="" contact="" with="" the="" hearing="" protector="" can="" be="" a="" problem="" associated="" with="" its="" use.="" in="" earlog="" 5,="" berger="" (1980)="" states="" that="" permanent="" [non-disposable]="" hearing="" protectors="" should="" be="" replaced="" between="" two="" and="" 12="" times="" per="" year.="" the="" constant="" wearing="" of="" hearing="" protectors="" causes="" them="" to="" lose="" their="" effectiveness.="" for="" example,="" headbands="" on="" earmuffs="" can="" lose="" their="" compression="" ability;="" the="" soft="" seals="" surrounding="" the="" ear="" cup="" on="" earmuffs="" can="" become="" inflexible;="" and="" plastic="" earplugs="" can="" develop="" cracks,="" can="" shrink,="" or="" can="" lose="" their="" elasticity.="" as="" referenced="" in="" earlog="" 17="" (berger,="" 1985),="" forshaw="" and="" cruchley="" studied="" the="" effects="" of="" washing="" the="" hearing="" protectors="" worn="" by="" long-="" range="" patrol="" aircraft="" crews.="" the="" crews="" were="" divided="" into="" three="" groups:="" one="" group="" wore="" pre-molded="" earplugs;="" the="" second="" group="" wore="" foam="" earplugs="" washed="" after="" each="" use;="" and="" the="" third="" group="" wore="" foam="" earplugs="" which="" were="" washed="" weekly.="" examinations="" by="" medical="" officers="" revealed="" no="" fungal="" or="" clinically="" significant="" bacterial="" infections="" among="" the="" three="" groups.="" msha="" also="" reviewed="" standards="" from="" the="" u.s.="" armed="" forces="" and="" the="" international="" community="" on="" the="" topic="" of="" hearing="" protector="" maintenance.="" the="" consensus="" of="" the="" standards="" was="" that="" damaged="" or="" deteriorated="" hearing="" protectors="" must="" be="" replaced.="" miners="" have="" also="" been="" known="" to="" alter="" the="" hearing="" protection="" provided="" to="" make="" them="" more="" comfortable.="" such="" alterations="" have="" included="" cutting="" off="" the="" end="" of="" earplugs="" or="" stretching="" out="" the="" head-band="" on="" earmuffs.="" these="" alterations="" can="" significantly="" decrease="" the="" hearing="" protector's="" attenuation.="" hearing="" protectors="" can="" also="" be="" damaged="" from="" exposure="" to="" heat,="" cold,="" ozone,="" chemicals,="" or="" dirt.="" such="" conditions="" are="" common="" in="" the="" mining="" industry,="" and="" mine="" operators="" must="" periodically="" check="" the="" hearing="" protectors="" provided="" and="" replace="" them="" when="" damage="" is="" found.="" hearing="" protectors="" provided="" at="" no="" cost="" to="" miner="" the="" proposal="" would="" also="" require="" the="" mine="" operator="" to="" provide="" necessary="" replacements="" at="" no="" cost.="" this="" is="" intended="" to="" ensure="" that="" the="" mine="" operator="" repairs="" or="" replaces="" a="" miner's="" hearing="" protector="" when="" it="" becomes="" damaged="" or="" deteriorated="" to="" the="" point="" that="" the="" required="" protection="" is="" compromised.="" msha="" believes="" that="" it="" is="" essential="" for="" mine="" operators="" to="" replace="" worn-out="" or="" damaged="" hearing="" protectors="" in="" order="" to="" maintain="" their="" effectiveness.="" this="" is="" in="" agreement="" with="" the="" international="" community="" and="" the="" u.s.="" armed="" services.="" damaged="" or="" deteriorated="" hearing="" protectors="" do="" not="" provide="" their="" designed="" optimum="" amount="" of="" protection.="" further,="" msha="" believes="" that="" the="" manufacturer's="" instructions="" are="" the="" best="" source="" of="" information="" as="" to="" the="" proper="" procedures="" for="" maintaining="" a="" particular="" protector.="" msha's="" existing="" noise="" standards="" do="" not="" specifically="" address="" the="" replacement="" of="" hearing="" protectors.="" osha's="" noise="" standards="" simply="" require="" that="" hearing="" protectors="" be="" replaced="" as="" necessary.="" msha="" received="" no="" direct="" comments="" to="" its="" anprm="" on="" the="" issue="" of="" mine="" operators="" supplying="" commercially="" available="" hearing="" protectors="" at="" no="" cost="" to="" the="" miner.="" however,="" several="" commenters="" supported="" adopting="" requirements="" similar="" to="" osha's="" which="" includes="" provisions="" for="" providing="" hearing="" protectors="" at="" no="" cost="" to="" the="" worker.="" replacement="" of="" hearing="" protectors="" would="" be="" based="" on="" the="" manufacturer's="" instructions,="" upon="" finding="" any="" deterioration="" that="" could="" adversely="" affect="" the="" hearing="" protectors="" attenuation,="" or="" upon="" a="" need="" for="" the="" miner="" to="" choose="" a="" different="" hearing="" protector="" due="" to="" a="" medical="" pathology="" caused="" or="" aggravated="" by="" the="" initial="" hearing="" protector="" provided="" (see="" following="" section="" which="" discusses="" medical="" pathology).="" for="" example,="" manufacturers="" of="" disposable="" earplugs="" may="" state="" in="" their="" instructions="" that="" they="" should="" be="" replaced="" after="" each="" use.="" replacement="" of="" hearing="" protector="" due="" to="" medical="" pathology="" msha's="" proposal="" would="" also="" require="" the="" mine="" operator="" to="" provide="" an="" individual="" miner="" with="" a="" different,="" more="" acceptable,="" type="" of="" hearing="" protector="" when="" presented="" with="" evidence="" of="" a="" medical="" pathology="" (e.g.,="" otitis="" externa="" or="" contact="" dermatitis).="" the="" definition="" of="" ``medical="" pathology''="" is="" intended="" to="" be="" broad="" enough="" to="" cover="" injuries.="" if,="" for="" example,="" a="" miner="" would="" suffer="" a="" burn="" in="" the="" ear="" canal="" which="" would="" preclude="" the="" wearing="" of="" earplugs,="" an="" employee="" who="" [[page="" 66428]]="" elected="" earplugs="" should="" have="" the="" opportunity="" to="" now="" select="" a="" muff.="" msha="" does="" not="" intend="" to="" require="" that="" the="" evidence="" of="" a="" medical="" pathology="" be="" a="" diagnosis="" by="" a="" physician="" specialist--nor="" to="" require="" mine="" operator="" action="" without="" any="" evidence="" whatsoever.="" the="" goal="" here="" is="" a="" practical="" one:="" exchange="" the="" hearing="" protector="" if="" there="" appears="" to="" be="" a="" medical="" problem.="" a="" preliminary="" diagnosis="" of="" medical="" pathology="" by="" a="" family="" physician="" or="" nurse="" should="" be="" accepted="" by="" an="" employer="" for="" the="" purposes="" of="" this="" requirement.="" in="" earlog="" 17,="" berger="" (1985)="" discusses="" some="" predisposing="" factors="" for="" otitis="" externa.="" these="" include="" allergy="" to="" chemicals="" or="" hair="" dyes="" and="" sprays;="" dermatitis;="" chronic="" draining="" middle="" ear="" infections;="" excessive="" cerumen="" (ear="" wax);="" and="" systemic="" conditions="" which="" lower="" the="" body="" resistance,="" such="" as="" anemia,="" vitamin="" deficiencies,="" diabetes,="" and="" endocrine="" disorders.="" disposable="" hearing="" protectors="" may="" be="" warranted="" for="" those="" individuals="" prone="" to="" infections.="" the="" researcher="" reported="" that="" the="" prevalence="" of="" otitis="" externa="" is="" approximately="" 2%="" in="" both="" users="" and="" nonusers="" of="" hearing="" protectors.="" he="" stated="" that:="" although="" hearing="" protection="" devices="" should="" not="" be="" worn="" in="" the="" presence="" of="" some="" preexisting="" ear="" canal="" pathologies,="" and="" care="" must="" be="" exercised="" regarding="" selection="" and="" use="" under="" certain="" environmental="" conditions,="" regular="" wearing="" of="" hpds="" does="" not="" normally="" increase="" the="" likelihood="" of="" contracting="" otitis="" externa.="" furthermore,="" royster="" and="" royster="" in="" earlog="" 17="" (berger,="" 1985)="" reported="" on="" a="" situation="" in="" which="" underground="" miners="" in="" a="" warm="" and="" humid="" environment="" were="" experiencing="" otitis="" externa.="" switching="" from="" a="" pre-="" molded="" vinyl="" earplug="" to="" a="" foam="" earplug="" decreased="" the="" incidence="" of="" this="" condition.="" although="" documented="" cases="" of="" hearing="" protectors="" causing="" infections="" in="" the="" ear="" canal="" or="" on="" the="" skin="" surrounding="" the="" ear="" are="" not="" prevalent,="" msha="" is="" aware="" of="" at="" least="" one="" reported="" case="" of="" an="" ear="" infection="" in="" the="" mining="" industry="" specifically="" attributed="" to="" the="" use="" of="" hearing="" protectors.="" msha's="" existing="" noise="" standards="" do="" not="" specifically="" address="" the="" replacement="" of="" hearing="" protectors.="" osha's="" noise="" standards="" simply="" require="" that="" hearing="" protectors="" be="" replaced="" as="" necessary.="" based="" upon="" the="" research="" and="" several="" international="" standards,="" msha="" believes="" that="" hearing="" protectors="" need="" to="" be="" replaced="" whenever="" a="" medical="" pathology="" is="" present.="" such="" replacements="" would="" also="" be="" at="" no="" cost="" to="" the="" miner.="" section="" 62.130="" training="" summary="" proposed="" sec.="" 62.130="" would="" provide="" the="" specifications="" for="" instruction="" and="" certification="" of="" training="" required="" by="" the="" proposed="" rule.="" proposed="" sec.="" 62.120="" requires="" such="" training="" for="" all="" miners="" exposed="" above="" the="" action="" level,="" and="" annually="" thereafter="" if="" still="" exposed="" above="" that="" level.="" proposed="" sec.="" 62.180="" requires="" retraining="" for="" every="" miner="" who="" incurs="" an="" sts.="" miners="" would="" receive="" instruction="" in="" the="" value="" of="" hearing="" protectors,="" selection="" and="" fitting="" of="" protectors,="" and="" proper="" use="" of="" such="" protectors.="" miners="" would="" also="" receive="" instruction="" as="" to="" the="" operation="" of="" an="" operator's="" hearing="" program="" and="" in="" the="" mine="" operator's="" noise="" control="" efforts.="" there="" are="" no="" special="" qualifications="" for="" instructors,="" nor="" any="" specifications="" on="" the="" hours="" of="" instruction.="" training="" is="" required="" to="" be="" provided="" without="" cost="" to="" the="" miner.="" the="" mine="" operator="" would="" be="" required="" to="" certify="" the="" completion="" of="" any="" training="" required="" by="" this="" part,="" and="" maintain="" the="" most="" recent="" certification="" for="" a="" miner="" at="" the="" mine="" site="" for="" as="" long="" as="" the="" miner="" is="" required="" to="" use="" hearing="" protectors="" or="" be="" enrolled="" in="" an="" hcp,="" and="" at="" least="" 6="" months="" thereafter.="" msha="" considered="" whether="" the="" requirements="" of="" part="" 48,="" ``training="" and="" retraining="" of="" miners,''="" were="" adequate="" to="" ensure="" the="" training="" required="" under="" this="" part.="" the="" requirements="" of="" part="" 48="" specify="" the="" initial="" and="" annual="" retraining="" of="" all="" miners="" in="" a="" list="" of="" subjects,="" many="" specified="" in="" the="" law="" itself="" (section="" 115="" of="" the="" mine="" safety="" and="" health="" act).="" the="" importance="" of="" this="" training="" is="" emphasized="" by="" statutory="" requirements="" for="" the="" submittal="" of="" training="" plans,="" on="" the="" specification="" of="" the="" hours="" to="" be="" devoted="" to="" the="" training,="" and="" on="" the="" qualifications="" of="" instructors.="" training="" is="" required="" on="" noise,="" but="" it="" is="" in="" general="" terms,="" covering="" the="" purpose="" of="" taking="" exposure="" measurements="" and="" on="" any="" health="" control="" plan="" in="" effect="" at="" the="" mine.="" mine="" operators="" may="" provide="" additional="" training,="" but="" the="" topics="" that="" need="" to="" be="" covered="" often="" make="" this="" impracticable="" within="" the="" prescribed="" time="" limits.="" after="" considering="" the="" available="" information="" about="" the="" importance="" and="" prevalence="" of="" training="" requirements,="" and="" based="" upon="" its="" experience="" in="" implementing="" the="" requirements="" of="" part="" 48,="" msha="" has="" determined="" that="" the="" requirements="" of="" part="" 48="" do="" not="" provide="" adequate="" noise="" training="" for="" those="" miners="" for="" whom="" exposure="" is="" clearly="" a="" problem.="" part="" 48="" training="" is="" neither="" comprehensive="" enough="" to="" provide="" such="" miners="" with="" the="" level="" of="" education="" needed="" for="" the="" proper="" use="" of="" hearing="" protection="" devices,="" nor,="" in="" the="" case="" of="" noisy="" mines,="" detailed="" enough="" on="" methods="" to="" reduce="" sound="" levels.="" nevertheless,="" msha="" believes="" compliance="" with="" this="" proposal="" can="" in="" many="" cases="" be="" fulfilled="" at="" the="" same="" time="" as="" scheduled="" part="" 48="" training.="" the="" agency="" does="" not="" believe="" special="" language="" in="" proposed="" part="" 62="" is="" required="" to="" permit="" this="" action="" under="" part="" 48,="" but="" welcomes="" comment="" in="" this="" regard.="" mine="" operators="" who="" can="" do="" so="" are="" free="" to="" fulfill="" their="" training="" requirements="" under="" sec.="" 62.120="" by="" covering="" the="" topics="" in="" initial="" and="" annual="" part="" 48="" training,="" and="" so="" certify="" on="" the="" separate="" form="" required="" by="" this="" part.="" if="" incorporated="" into="" part="" 48,="" mine="" operators="" would,="" however,="" be="" required="" to="" submit="" a="" revised="" training="" plan="" to="" the="" local="" district="" office="" for="" approval.="" some="" mine="" operators="" may="" not="" have="" room="" in="" their="" part="" 48="" plans,="" however,="" to="" be="" able="" to="" incorporate="" these="" topics.="" moreover,="" some="" training="" required="" under="" the="" proposal="" will="" clearly="" not="" fit="" within="" a="" regular="" schedule:="" e.g.,="" the="" training="" required="" by="" sec.="" 62.180="" whenever="" a="" standard="" threshold="" shift="" in="" hearing="" acuity="" is="" detected.="" msha="" has="" endeavored="" to="" make="" the="" training="" requirements="" as="" simple="" as="" possible.="" if="" conducted="" separate="" from="" part="" 48,="" there="" are="" no="" specifications="" on="" trainer="" qualifications,="" no="" minimal="" training="" time,="" nor="" any="" training="" plans.="" if="" however="" the="" training="" is="" incorporated="" into="" part="" 48,="" then="" all="" applicable="" part="" 48="" requirements="" will="" have="" to="" be="" met.="" background="" training="" requirements="" are="" a="" mainstay="" of="" mine="" safety="" and="" health.="" although="" msha="" has="" no="" training="" requirements="" in="" its="" existing="" noise="" regulations,="" the="" general="" training="" requirements="" set="" forth="" in="" part="" 48="" require="" basic="" training="" as="" to="" the="" purpose="" of="" taking="" noise="" measurements,="" and="" in="" any="" health="" (noise)="" control="" plans="" that="" are="" in="" effect="" at="" the="" mine.="" numerous="" commenters="" responding="" to="" msha's="" anprm,="" expressed="" considerable="" support="" for="" miner="" training="" on="" noise="" and="" its="" effects="" and="" believed="" that="" it="" is="" an="" essential="" element="" of="" any="" effective="" hcp.="" many="" of="" these="" commenters="" specifically="" supported="" annual="" refresher="" training.="" commenters="" differed,="" however,="" in="" their="" opinions="" as="" to="" how="" training="" could="" best="" be="" accomplished.="" several="" commenters="" recommended="" that="" msha="" incorporate="" any="" training="" requirements="" related="" to="" this="" standard="" into="" msha's="" existing="" training="" requirements="" under="" 30="" cfr="" part="" 48--training="" and="" retraining="" of="" miners.="" a="" few="" commenters="" believed="" that="" the="" training="" requirements="" in="" msha's="" part="" 48="" were="" adequate="" and="" that="" no="" additional="" instruction="" was="" needed.="" [[page="" 66429]]="" one="" commenter="" suggests="" that="" the="" initial="" training="" class="" be="" limited="" to="" less="" than="" 10="" individuals="" (berger,="" 1988;="" royster="" and="" royster,="" 1985).="" although="" training="" may="" best="" be="" accomplished="" in="" small="" groups,="" msha's="" proposal="" would="" not="" limit="" the="" size="" of="" any="" training="" classes.="" there="" is="" considerable="" precedent="" for="" requiring="" training="" as="" part="" of="" noise="" control="" programs.="" osha's="" noise="" standard="" has="" training="" requirements="" which="" are="" similar="" to="" those="" in="" msha's="" proposed="" noise="" standard="" with="" a="" few="" exceptions.="" these="" exceptions="" are="" discussed="" later="" in="" this="" section.="" in="" osha's="" 1981="" preamble="" (46="" fr="" 4157),="" morrill="" stresses="" the="" importance="" of="" worker="" education="" in="" overcoming="" workers="" objections="" to="" wearing="" hearing="" protectors.="" this="" document="" quotes="" a="" dr.="" maas="" as="" saying="" that,="" ``supervisors="" must="" sell="" employees="" on="" the="" need="" and="" value="" of="" hearing="" protection="" devices.="" when="" employees="" understand="" what="" the="" protective="" measure="" is="" for,="" it="" will="" be="" accepted="" because="" the="" employee="" realizes="" it="" is="" for="" his="" own="" good.''="" a="" number="" of="" comments="" to="" osha's="" hearing="" conservation="" amendment="" (46="" fr="" 4157)="" indicated="" that="" workers="" are="" reluctant="" to="" appear="" weak="" or="" ridiculous="" as="" a="" result="" of="" wearing="" hearing="" protectors.="" suter="" (1986)="" states,="" ``workers="" who="" understand="" the="" mechanism="" of="" hearing="" and="" how="" it="" is="" lost="" will="" be="" more="" motivated="" to="" protect="" themselves.''="" other="" researchers="" concur="" with="" this="" opinion="" (wright,="" (1980)="" and="" royster="" et="" al.,="" (1982)).="" caohc="" (miller,="" 1985)="" states="" the="" following="" regarding="" the="" need="" for="" training="" as="" part="" of="" an="" effective="" program="" (hcp):="" a="" critical="" component="" of="" the="" ohc="" [occupational="" hearing="" conservation]="" program="" is="" the="" employee="" education="" program="" (eep).="" in="" many="" respects,="" the="" eep="" is="" the="" most="" important="" aspect="" of="" the="" ohc="" program="" since="" it="" is="" designed="" to="" increase="" the="" auditory="" consciousness="" of="" the="" employee="" regarding="" the="" hazardous="" effects="" of="" noise="" exposure="" and="" by="" so="" doing="" to="" get="" him="" to="" use="" effective="" forms="" of="" phpd's="" [personal="" hearing="" protective="" devices]="" conscientiously="" and="" consistently.="" such="" use="" of="" phpd's="" will="" actually="" protect="" the="" worker's="" hearing,="" while="" the="" other="" aspects="" of="" the="" program,="" important="" as="" they="" are,="" will="" not="" do="" so.="" no="" amount="" of="" noise="" monitoring="" or="" audiometric="" testing,="" for="" example,="" will="" protect="" hearing.="" msha="" also="" reviewed="" the="" training="" requirements="" set="" forth="" in="" international="" standards="" and="" those="" of="" the="" u.s.="" armed="" services.="" the="" consensus="" was="" that="" training="" was="" necessary;="" however,="" the="" training="" interval="" was="" not="" always="" specified.="" training="" about="" hearing="" protector="" selection="" and="" use="" section="" 62.130(a)="" specifically="" provides="" that="" the="" training="" is="" to="" include="" instruction="" in--="" (1)="" the="" effects="" of="" noise="" on="" hearing;="" (2)="" the="" purpose="" and="" value="" of="" wearing="" hearing="" protectors;="" (3)="" the="" advantages="" and="" disadvantages="" of="" the="" hearing="" protectors="" to="" be="" offered;="" (4)="" the="" care,="" fitting,="" and="" use="" of="" the="" hearing="" protector="" worn="" by="" the="" miner;="" (5)="" the="" general="" requirements="" of="" the="" regulation;="" (6)="" the="" operator's="" and="" miner's="" respective="" tasks="" in="" maintaining="" mine="" noise="" controls;="" and="" (7)="" the="" purpose="" and="" value="" of="" audiometric="" testing="" and="" a="" summary="" of="" the="" procedures.="" osha="" requires="" annual="" training="" on="" the="" same="" elements="" except="" it="" does="" not="" require="" training="" on="" the="" requirements="" of="" its="" noise="" standard.="" it="" is="" msha's="" view,="" however,="" that="" some="" training="" on="" the="" requirements="" of="" the="" standard="" is="" necessary="" in="" order="" for="" employees="" to="" understand="" the="" role="" hearing="" protection="" plays="" in="" a="" broader="" protection="" scheme.="" purpose,="" advantages,="" and="" disadvantages="" of="" hearing="" protectors="" offered="" instruction="" on="" this="" topic="" would="" help="" the="" miner="" make="" an="" informed="" choice="" as="" to="" which="" hearing="" protector="" to="" use.="" this="" basic="" instruction="" would="" be="" initially="" required="" when="" the="" mine="" operator="" first="" determines="" the="" miner's="" noise="" exposure="" exceeds="" the="" action="" level.="" moreover,="" pursuant="" to="" proposed="" sec.="" 62.125,="" this="" instruction="" must="" be="" provided="" at="" least="" once="" before="" the="" miner="" must="" make="" a="" selection="" of="" a="" hearing="" protector.="" furthermore,="" it="" would="" need="" to="" be="" repeated="" annually="" thereafter,="" because="" hearing="" protectors="" should="" be="" replaced="" periodically.="" msha="" anticipates="" the="" training="" would="" address="" specific="" advantages="" and="" disadvantages="" of="" earmuffs,="" earplugs,="" and="" canal="" caps="" as="" they="" relate="" to="" the="" needs="" of="" the="" miner="" and="" the="" specific="" conditions="" at="" the="" mine.="" for="" example,="" an="" electrician="" who="" opts="" to="" use="" an="" earmuff="" must="" understand="" the="" need="" to="" use="" one="" with="" dielectric="" properties="" to="" minimize="" the="" chance="" of="" incurring="" an="" electrical="" shock="" when="" working="" around="" energized="" equipment.="" an="" over-the-head="" earmuff="" is="" unsuited="" for="" those="" miners="" required="" to="" wear="" hardhats:="" the="" earmuff="" would="" interfere="" with="" the="" wearing="" of="" the="" hardhat="" as="" the="" hardhat="" could="" not="" be="" placed="" over="" the="" headband.="" in="" addition,="" the="" mine="" operator="" should="" discuss="" the="" specific="" advantages="" and="" disadvantages="" of="" any="" special="" hearing="" protectors="" offered="" such="" as="" active="" noise="" reduction,="" level-dependent,="" flat-response,="" and="" notch-amplification="" hearing="" protectors,="" or="" a="" communication="" headset.="" for="" example,="" a="" miner="" with="" a="" sensorineural="" hearing="" loss="" in="" the="" higher="" frequencies="" may="" require="" a="" different="" type="" of="" hearing="" protector="" than="" a="" miner="" with="" a="" conductive="" hearing="" loss="" across="" all="" frequencies.="" accommodating="" the="" hearing="" loss="" may="" require="" a="" level-dependent,="" active="" noise="" reduction,="" or="" notch-="" amplification="" hearing="" protector="" to="" improve="" the="" miner's="" ability="" to="" communicate="" and="" hear="" warning="" signals="" in="" a="" noisy="" environment.="" all="" miners="" need="" to="" understand="" the="" relative="" advantages="" and="" disadvantages="" of="" earmuffs="" and="" earplugs="" as="" they="" are="" not="" at="" all="" obvious:="" hence,="" the="" necessity="" for="" training.="" some="" advantages="" of="" earmuffs="" (circumaural="" hearing="" protectors)="" include:="" they="" are="" easily="" donned="" and="" removed="" by="" the="" miner="" when="" working="" in="" intermittent="" noise;="" they="" offer="" protection="" against="" dust="" in="" the="" ear="" canal;="" they="" are="" not="" easily="" misplaced="" or="" lost;="" they="" fit="" people="" with="" unusually="" shaped="" ear="" canals;="" and="" they="" can="" be="" worn="" over="" earplugs.="" berger="" in="" earlog="" 3="" (1980),="" and="" coleman="" et="" al.="" (1984)="" reported="" that="" one="" major="" disadvantage="" of="" earmuffs="" is="" that="" they="" hinder="" a="" miner's="" ability="" to="" localize="" the="" direction="" of="" sounds.="" if="" the="" miner's="" safety="" depends="" on="" the="" ability="" to="" localize="" sounds,="" then="" this="" disadvantage="" would="" preclude="" the="" use="" of="" earmuffs.="" other="" potential="" disadvantages="" of="" earmuffs="" include:="" discomfort;="" headache;="" a="" feeling="" of="" claustrophobia;="" excessive="" warmth="" and="" perspiration="" under="" the="" muff="" seal;="" and="" skin="" irritation.="" earmuffs="" may="" present="" problems="" if="" the="" miner="" wears="" safety="" glasses="" or="" earrings.="" eyeglass="" temples="" reduce="" the="" attenuation="" afforded="" by="" earmuffs.="" in="" earlog="" 19,="" berger="" (1988)="" states="" that="" the="" use="" of="" eyeglasses="" with="" an="" earmuff="" can="" break="" the="" seal="" of="" the="" earmuff="" and="" cause="" a="" loss="" of="" attenuation="" of="" up="" to="" 6="" db="" depending="" on="" the="" frequency="" of="" the="" noise.="" royster="" et="" al.="" (1996)="" tested="" the="" effect="" of="" wearing="" two="" different="" safety="" glasses="" on="" the="" attenuation="" of="" an="" earmuff.="" the="" researchers="" found="" that="" the="" attenuation="" was="" reduced="" by="" about="" 5="" db="" across="" all="" frequencies.="" barham="" et="" al.="" (1989)="" investigated="" the="" effects="" of="" safety="" glasses="" and="" hair="" on="" the="" effectiveness="" of="" earmuffs.="" the="" wearing="" of="" safety="" glasses="" decreased="" the="" noise="" reduction="" up="" to="" 4="" db="" depending="" upon="" the="" frequency.="" the="" glasses="" had="" slender="" and="" flexible="" wire-reinforced="" side="" frames="" so="" that="" the="" side="" frames="" would="" fit="" close="" to="" the="" head.="" not="" only="" did="" the="" safety="" glasses="" decrease="" the="" average="" noise="" reduction,="" they="" also="" reduced="" the="" variability="" (standard="" deviation)="" of="" the="" [[page="" 66430]]="" noise="" reduction="" realized="" among="" the="" individuals.="" the="" type="" of="" hair="" and="" its="" length="" influenced="" the="" noise="" reduction="" provided="" by="" earmuffs.="" individuals="" with="" short="" hair="" realized="" up="" to="" 5="" db="" more="" protection,="" depending="" upon="" the="" frequency,="" than="" individuals="" with="" long="" or="" curly="" hair="" and="" beards.="" michael="" (1991)="" asserts="" that="" glasses="" with="" plastic="" temples="" may="" cause="" a="" loss="" of="" attenuation="" from="" 1="" to="" 8="" db,="" due="" to="" breaking="" the="" seal="" of="" the="" earmuff.="" in="" some="" cases,="" this="" loss="" can="" be="" substantially="" reduced="" if="" small,="" close="" fitting="" wire="" temples="" are="" employed.="" nixon="" and="" berger="" (1991)="" report="" that="" temples="" of="" eyeglasses="" reduce="" the="" efficacy="" of="" earmuffs="" normally="" by="" 3="" to="" 7="" db="" provided="" the="" cushions="" of="" the="" earmuffs="" are="" in="" good="" shape.="" this="" effect="" varies="" among="" earmuffs="" and="" it="" also="" depends="" upon="" the="" style="" and="" fit="" of="" the="" eyeglasses.="" to="" minimize="" the="" effect="" of="" wearing="" eyeglasses,="" the="" temples="" should="" be="" as="" thin="" as="" possible="" and="" fit="" close="" to="" the="" side="" of="" the="" head.="" savich="" (1979)="" measured="" the="" noise="" attenuation="" of="" earmuffs.="" because="" of="" long="" hair="" and="" safety="" glasses,="" the="" earmuffs="" provided="" less="" attenuation="" than="" expected="" based="" upon="" laboratory="" tests.="" furthermore,="" head="" size="" has="" a="" significant="" influence="" on="" the="" attenuation="" because="" of="" different="" clamping="" forces.="" increased="" clamping="" force="" increases="" the="" attenuation.="" some="" advantages="" of="" earplugs="" include:="" they="" are="" cooler,="" if="" the="" miner="" has="" to="" work="" in="" a="" hot,="" humid="" environment;="" they="" are="" more="" easily="" worn="" with="" safety="" glasses,="" hardhats,="" and="" other="" personal="" safety="" equipment="" (e.g.,="" air-purifying="" or="" welding="" helmets);="" and="" they="" fit="" miners="" who="" have="" extremely="" large="" external="" ears.="" one="" disadvantage="" of="" an="" earplug="" is="" that="" inserting="" it="" into="" the="" ear="" canal="" could="" present="" a="" personal="" hygiene="" problem="" if="" the="" miner="" removes="" and="" reinserts="" it="" several="" times="" during="" the="" day.="" a="" miner="" who="" is="" susceptible="" to="" ear="" infections="" or="" secretes="" significant="" amounts="" of="" ear="" wax="" may="" be="" better="" suited="" for="" using="" earmuffs.="" as="" noted="" earlier="" in="" this="" section,="" training="" is="" critical="" to="" miner="" cooperation.="" msha="" has="" concluded,="" after="" reviewing="" the="" scientific="" literature,="" u.s.="" armed="" forces="" regulations,="" and="" standards="" from="" the="" international="" community,="" that="" requiring="" the="" mine="" operator="" to="" instruct="" each="" miner="" required="" to="" wear="" hearing="" protectors="" on="" the="" purpose,="" advantages,="" and="" disadvantages="" of="" the="" choices="" available="" will="" facilitate="" hearing="" protector="" use="" and="" effectiveness.="" care,="" fitting,="" and="" use="" of="" the="" hearing="" protector="" selected="" in="" response="" to="" msha's="" anprm,="" many="" commenters="" supported="" the="" need="" to="" train="" employees="" on="" the="" proper="" fitting,="" care,="" and="" use="" of="" hearing="" protectors.="" merry="" et="" al.="" (1992)="" studied="" the="" effect="" of="" fitting="" instructions="" on="" the="" resulting="" attenuations="" of="" earplugs.="" novice="" subjects="" were="" given="" earplugs.="" the="" difference="" in="" their="" hearing="" thresholds="" between="" the="" unoccluded="" and="" occluded="" conditions="" was="" the="" attenuation="" of="" the="" earplug.="" the="" subjects="" obtained="" greater="" attenuation="" whenever="" the="" experimenter="" assisted="" the="" subject="" in="" fitting="" the="" earplug="" than="" when="" the="" subject="" merely="" read="" the="" manufacturer's="" instructions="" before="" donning="" the="" earplug.="" furthermore,="" the="" researchers="" noted="" that="" the="" attenuations="" obtained="" by="" the="" subject="" when="" just="" the="" manufacturer's="" instructions="" were="" read="" is="" comparable="" to="" the="" attenuations="" measured="" under="" industrial="" conditions.="" casali="" and="" lam="" (1986)="" reported="" that="" the="" proper="" design="" and="" presentation="" of="" user="" insertion/donning="" instructions="" are="" critical="" to="" the="" amount="" of="" attenuation="" afforded="" by="" hearing="" protectors.="" they="" found="" that="" in="" some="" cases,="" the="" magnitude="" of="" protection="" afforded="" by="" the="" use="" of="" earplugs="" exhibited="" greater="" than="" a="" twofold="" increase="" when="" training="" ranged="" from="" no="" instruction="" to="" detailed="" and="" model="" instruction.="" their="" study="" also="" showed="" that="" the="" attenuations="" afforded="" by="" earmuffs="" and="" earcaps="" were="" not="" as="" influenced="" by="" the="" level="" of="" instruction="" as="" were="" earplugs.="" casali="" and="" lam="" concluded="" that="" any="" instruction="" technique="" provided="" an="" improvement="" in="" attenuation="" over="" no="" instruction="" at="" all.="" however,="" they="" found="" no="" statistically="" significant="" differences="" among="" the="" type="" of="" instruction="" used.="" they="" also="" stated="" that="" regardless="" of="" the="" insertion/application="" instruction="" type="" selected,="" it="" is="" imperative="" that="" workers="" be="" retrained="" periodically="" in="" hearing="" protector="" insertion="" practices,="" hearing="" protector="" sizing,="" and="" hearing="" protector="" care="" to="" maintain="" optimal="" hearing="" conservation.="" royster="" et="" al.="" (1996)="" had="" novice="" users="" of="" hearing="" protectors="" don="" the="" protectors="" after="" reading="" the="" manufacturer's="" instructions.="" since="" some="" users="" failed="" to="" properly="" don="" the="" hearing="" protectors,="" the="" researchers="" concluded="" that="" the="" instructions="" provided="" by="" the="" manufacturer="" were="" not="" always="" adequate.="" consequently,="" additional="" instruction="" should="" be="" provided="" to="" assure="" the="" proper="" donning="" of="" hearing="" protectors.="" barham="" et="" al.="" (1989)="" reported="" that="" the="" noise="" reduction="" achieved="" by="" an="" earmuff="" improved="" by="" approximately="" 4="" db="" for="" a="" group="" and="" up="" to="" 6="" db="" for="" an="" individual="" following="" instruction="" on="" its="" use.="" not="" only="" did="" the="" attenuation="" increase="" but="" also="" the="" standard="" deviation="" (a="" measure="" of="" variability)="" decreased.="" therefore,="" instruction="" significantly="" improved="" the="" noise="" reduction="" achieved="" by="" the="" wearer="" of="" an="" earmuff.="" park="" and="" casali="" (1991)="" studied="" the="" effects="" of="" two="" levels="" (minimal="" and="" detailed)="" of="" instruction="" on="" the="" measured="" attenuation="" obtained="" by="" regular="" hearing="" protector="" users.="" the="" users="" were="" tested="" using="" different="" hearing="" protectors="" from="" the="" ones="" they="" normally="" wore.="" the="" amount="" of="" noise="" attenuation="" increased="" and="" the="" standard="" deviations="" decreased="" when="" the="" investigators="" presented="" the="" instructions="" and="" demonstrated="" the="" proper="" manner="" to="" don="" and="" doff="" hearing="" protectors="" as="" compared="" to="" the="" employees="" simply="" reading="" the="" instructions.="" the="" efficiency="" of="" earplugs="" was="" found="" to="" be="" highly="" sensitive="" to="" the="" degree="" of="" instruction="" while="" earmuffs="" and="" canal="" caps="" were="" not.="" msha="" believes="" that="" training="" is="" critical="" to="" the="" effective="" use="" of="" hearing="" protectors,="" and="" that="" miners="" must="" be="" shown="" how="" to="" use,="" fit,="" and="" care="" for="" their="" hearing="" protectors="" if="" they="" are="" to="" be="" effective.="" further,="" the="" instructions="" should="" be="" repeated="" at="" yearly="" intervals="" to="" maintain="" effectiveness.="" simply="" instructing="" the="" miner="" to="" read="" manufacturer's="" directions="" on="" the="" hearing="" protector="" container="" would="" not="" be="" adequate.="" msha="" is="" concerned="" that="" some="" manufacturer's="" instructions="" are="" inadequate="" for="" the="" proper="" fitting="" of="" hearing="" protectors.="" the="" effectiveness="" of="" hearing="" protectors="" can="" be="" highly="" dependent="" on="" how="" they="" fit="" the="" individual="" wearer.="" not="" all="" people="" will="" achieve="" the="" same="" degree="" of="" fit="" or="" effectiveness="" from="" the="" same="" hearing="" protector.="" training="" about="" hearing="" conservation="" program="" and="" operator="" noise="" controls="" osha's="" noise="" standard="" has="" similar="" training="" requirements="" with="" the="" exception="" that="" they="" do="" not="" require="" training="" on="" the="" respective="" responsibilities="" of="" the="" employer="" and="" employee="" in="" maintaining="" controls.="" msha="" has="" determined="" that="" training="" miners="" enrolled="" in="" an="" hcp="" on="" the="" respective="" responsibilities="" of="" mine="" operator="" and="" miner="" is="" necessary="" to="" obtain="" maximum="" effectiveness="" from="" an="" hcp.="" miner="" cooperation="" and="" support="" is="" required,="" for="" example,="" to="" ensure:="" (1)="" the="" hearing="" protector="" provided="" fits="" properly="" each="" time="" it="" is="" donned;="" (2)="" the="" hearing="" protector="" is="" worn="" whenever="" the="" miner="" is="" exposed="" to="" hazardous="" sound="" levels;="" (3)="" exposure="" to="" high="" sound="" levels="" is="" avoided="" for="" at="" least="" 14="" hours="" before="" taking="" the="" baseline="" audiogram;="" (4)="" participation="" in="" the="" audiometric="" testing;="" (5)="" cooperation="" with="" any="" administrative="" control(s)="" instituted="" by="" the="" mine="" operator;="" and="" [[page="" 66431]]="" (6)="" use="" and="" maintenance="" of="" the="" engineering="" noise="" controls="" provided="" by="" the="" mine="" operator.="" msha="" believes="" that="" a="" miner's="" understanding="" and="" motivation="" would="" be="" enhanced="" by="" conducting="" initial="" and="" annual="" training="" in="" these="" areas.="" the="" rationale="" for="" retraining="" miners="" who="" suffer="" an="" sts="" is="" discussed="" in="" connection="" with="" sec.="" 62.180,="" follow-up="" corrective="" measures="" when="" sts="" detected.="" msha="" believes="" that="" a="" miner="" must="" also="" be="" trained="" to="" understand="" the="" audiometric="" tests.="" this="" will="" enable="" miners="" to="" understand="" their="" own="" results="" and="" determine="" the="" effect="" of="" wearing="" hearing="" protectors.="" effectiveness.="" msha="" has="" endeavored="" to="" make="" the="" training="" requirements="" as="" simple="" as="" possible.="" if="" conducted="" separate="" from="" part="" 48,="" there="" are="" no="" specifications="" on="" trainer="" qualifications,="" no="" minimal="" training="" time,="" nor="" any="" training="" plans.="" if="" however="" the="" training="" is="" incorporated="" into="" part="" 48,="" then="" all="" applicable="" part="" 48="" requirements="" will="" have="" to="" be="" met.="" while="" this="" approach="" reduces="" the="" burden="" on="" those="" mine="" operators="" who="" cannot="" incorporate="" part="" or="" all="" of="" the="" noise="" training="" into="" part="" 48="" training,="" it="" also="" means="" that="" certain="" safeguards="" in="" effect="" for="" part="" 48="" training="" will="" not="" be="" directly="" applicable="" to="" that="" noise="" training="" not="" provided="" during="" part="" 48="" training.="" there="" would="" be="" no="" review="" of="" a="" noise="" training="" plan,="" for="" example,="" to="" ensure="" that="" the="" instruction="" is="" adequate="" or="" that="" the="" training="" is="" to="" be="" given="" in="" the="" language="" spoken="" by="" most="" of="" the="" miners.="" comments="" on="" this="" point="" are="" solicited.="" the="" agency="" believes="" it="" can="" ensure="" the="" noise="" requirements="" have="" been="" fulfilled="" by="" checking="" with="" exposed="" miners="" to="" ensure="" that="" the="" required="" training="" elements="" have="" been="" covered="" and="" that="" the="" certifications="" are="" valid.="" certification.="" section="" 62.130(b)="" of="" the="" proposal="" would="" require="" that,="" upon="" completion="" of="" any="" training="" required="" under="" this="" part,="" the="" mine="" operator="" certify="" the="" date="" and="" type="" of="" training="" (initial="" or="" annual)="" given="" each="" miner.="" the="" certification="" would="" be="" signed="" by="" the="" person="" conducting="" the="" training.="" it="" is="" standard="" practice="" in="" the="" mining="" industry="" to="" require="" certification="" of="" training,="" as="" a="" way="" of="" facilitating="" compliance.="" training="" received="" under="" part="" 48="" must="" be="" certified.="" the="" certification="" form="" used="" for="" part="" 48="" does="" not="" have="" a="" separate="" line="" on="" which="" to="" indicate="" that="" the="" training="" required="" under="" the="" proposed="" noise="" standard="" has="" been="" completed;="" moreover,="" this="" would="" not="" be="" suitable="" in="" any="" event="" for="" noise="" training="" given="" independently="" of="" part="" 48="" training="" as="" may="" often="" be="" the="" case.="" msha="" believes="" that="" it="" is="" important="" to="" record="" the="" type="" and="" date="" of="" any="" training="" conducted="" under="" its="" proposed="" noise="" regulations.="" a="" written="" record,="" together="" with="" miner="" interviews,="" provide="" the="" agency="" necessary="" checks="" to="" ensure="" the="" training="" is="" provided="" as="" required="" with="" only="" a="" minimal="" burden.="" an="" optional="" approach="" on="" which="" msha="" would="" welcome="" comment="" is="" to="" simply="" require="" that="" a="" mine="" operator="" must,="" upon="" request,="" give="" an="" msha="" inspector="" copies="" of="" all="" materials="" related="" to="" the="" employer's="" noise="" training="" program.="" this="" is="" the="" approach="" taken="" by="" osha.="" retention.="" section="" 62.130(b)="" of="" msha's="" proposal="" would="" require="" the="" mine="" operator="" to="" retain="" the="" most="" recent="" certification="" at="" the="" mine="" site="" for="" as="" long="" as="" the="" miner="" is="" exposed="" to="" noise="" above="" the="" level="" which="" initiated="" the="" training="" and="" for="" at="" least="" six="" months="" thereafter.="" msha="" has="" a="" retention="" requirement="" for="" part="" 48="" training.="" part="" 48="" training="" records="" are="" to="" be="" retained="" for="" two="" years="" for="" currently="" employed="" miners="" or="" for="" 60="" days="" after="" the="" termination="" of="" employment.="" osha="" has="" no="" retention="" requirement="" for="" training="" records.="" the="" agency="" believes="" it="" is="" important="" to="" retain="" training="" records="" in="" order="" to="" verify="" that="" the="" required="" training="" has="" been="" provided,="" as="" with="" the="" certification="" requirements.="" the="" retention="" requirement="" is="" short="" and="" not="" burdensome:="" only="" the="" most="" recent="" record="" must="" be="" retained,="" and="" then="" only="" until="" the="" miner's="" exposure="" drops="" beneath="" the="" level="" which="" initiated="" the="" training="" (or="" 6="" months="" after="" cessation="" if="" employment="" should="" that="" come="" before="" the="" exposure="" level="" has="" dropped).="" section="" 62.140="" audiometric="" testing="" program="" this="" section="" of="" the="" proposal="" would="" establish="" basic="" procedures="" for="" the="" audiometric="" testing="" program="" in="" which="" those="" miners="" enrolled="" in="" a="" hearing="" conservation="" program="" (hcp)="" will="" participate.="" it="" includes="" provisions="" for:="" qualifications="" of="" personnel="" performing="" the="" audiograms,="" baseline="" audiograms,="" annual="" audiograms,="" and="" supplemental="" baseline="" audiograms.="" msha="" is="" seeking="" explicit="" comment="" on="" a="" number="" of="" points.="" what="" follows="" is="" a="" brief="" summary="" of="" some="" key="" features="" of="" this="" section="" of="" the="" proposal.="" with="" respect="" to="" qualifications="" of="" personnel,="" msha="" would="" require="" that="" an="" ``audiologist''="" be="" certified="" by="" the="" american="" speech-language-="" hearing="" association="" or="" licensed="" by="" a="" state="" board="" of="" examiners.="" ``qualified="" technicians''="" would="" be="" required="" to="" have="" been="" certified="" by="" the="" council="" for="" accreditation="" in="" occupational="" hearing="" conservation="" (caohc)="" or="" another="" recognized="" organization="" offering="" equivalent="" certification.="" caohc="" or="" equivalent="" certification="" would="" assure="" that="" the="" technicians="" are="" qualified.="" msha="" is="" not="" proposing="" to="" require="" qualifications="" for="" physicians.="" it="" is="" critical="" to="" obtain="" a="" baseline="" audiogram="" before="" exposure="" to="" hazardous="" noise.="" if="" this="" is="" not="" possible,="" then="" the="" baseline="" is="" to="" be="" obtained="" as="" soon="" as="" is="" reasonably="" possible.="" due="" to="" remote="" locations="" and="" intermittent="" operations="" of="" many="" mines,="" msha="" determined="" that="" allowing="" six="" months="" (or="" 12="" months="" if="" a="" mobile="" test="" van="" is="" used)="" for="" obtaining="" the="" baseline="" audiogram="" was="" reasonable.="" the="" 12="" month="" period="" would="" allow="" mine="" operators="" to="" schedule="" many="" baseline="" and="" annual="" audiograms="" simultaneously,="" and="" thus,="" substantially="" reduce="" the="" cost="" when="" mobile="" test="" vans="" are="" used.="" pursuant="" to="" proposed="" sec.="" 62.120(b),="" miners="" would="" be="" provided="" hearing="" protection="" until="" such="" time="" as="" the="" baseline="" audiogram="" is="" conducted;="" and="" in="" the="" event="" the="" miner="" has="" to="" wait="" for="" more="" than="" 6="" months="" to="" get="" a="" baseline="" audiogram="" because="" a="" mobile="" test="" van="" is="" used,="" the="" operator="" would="" be="" required="" to="" ensure="" the="" use="" of="" hearing="" protection.="" msha="" has="" also="" determined="" that="" a="" 14-hour="" quiet="" period="" should="" precede="" the="" baseline="" audiogram="" to="" ensure="" a="" valid="" result:="" hearing="" protectors="" will="" not="" be="" considered="" a="" substitute="" for="" a="" quiet="" period="" under="" the="" proposal,="" and="" miners="" are="" to="" be="" notified="" of="" the="" importance="" of="" compliance="" with="" the="" quiet="" period.="" msha="" has="" concluded="" that="" audiograms="" need="" to="" be="" provided="" annually="" for="" miners="" enrolled="" in="" an="" hcp.="" msha="" is="" not="" proposing="" to="" require="" this="" quiet="" period="" for="" annual="" audiograms,="" though="" it="" may="" be="" in="" the="" mine="" operator's="" interest="" to="" do="" so.="" background="" under="" existing="" standards="" for="" coal="" mines,="" msha="" requires="" pre-="" employment="" and="" periodic="" audiograms="" at="" those="" mines="" under="" a="" hearing="" conservation="" plan,="" but="" includes="" no="" specific="" procedures="" or="" time="" frames="" for="" obtaining="" these="" audiograms.="" moreover,="" at="" present,="" less="" than="" 1%="" of="" the="" coal="" miners="" are="" covered="" by="" a="" hearing="" conservation="" plan.="" msha="" currently="" does="" not="" have="" any="" requirements="" addressing="" audiometric="" testing="" for="" metal="" and="" nonmetal="" mines.="" osha's="" noise="" standard="" also="" contains="" requirements="" for="" qualifications="" of="" personnel="" and="" for="" baseline,="" annual,="" and="" supplemental="" baseline="" audiograms.="" the="" limited="" number="" of="" differences="" between="" the="" osha="" standard="" and="" the="" msha="" proposal="" are="" noted="" in="" the="" discussion="" that="" follows.="" [[page="" 66432]]="" qualifications="" of="" personnel="" section="" 62.140(a)="" of="" msha's="" proposal="" would="" require="" that="" audiometric="" tests="" be="" conducted="" by="" a="" physician,="" an="" audiologist,="" or="" a="" qualified="" technician="" who="" is="" under="" the="" direction="" or="" supervision="" of="" a="" physician="" or="" an="" audiologist.="" msha="" would="" require="" that="" an="" ``audiologist''="" be="" certified="" by="" the="" american="" speech-language-hearing="" association="" or="" licensed="" by="" a="" state="" board="" of="" examiners.="" ``qualified="" technicians''="" would="" be="" required="" to="" have="" been="" certified="" by="" the="" council="" for="" accreditation="" and="" occupational="" hearing="" conservation="" (caohc)="" or="" another="" recognized="" organization="" offering="" equivalent="" certification.="" osha's="" noise="" standard="" requires="" that--="" audiometric="" tests="" shall="" be="" performed="" by="" a="" licensed="" or="" certified="" audiologist,="" otolaryngologist,="" or="" other="" physician,="" or="" by="" a="" technician="" who="" is="" certified="" by="" the="" council="" of="" accreditation="" for="" occupational="" hearing="" conservation,="" or="" who="" has="" satisfactorily="" demonstrated="" competence="" in="" administering="" audiometric="" examinations,="" obtaining="" valid="" audiograms,="" and="" properly="" using,="" maintaining="" and="" checking="" calibration="" and="" proper="" functioning="" of="" the="" audiometers="" being="" used.="" a="" technician="" who="" operated="" microprocessor="" audiometers="" does="" not="" need="" to="" be="" certified.="" a="" technician="" who="" performs="" audiometric="" tests="" must="" be="" responsible="" to="" an="" audiologist,="" otolaryngologist="" or="" physician.="" msha="" received="" comments="" that="" specifically="" addressed="" the="" qualifications="" of="" persons="" conducting="" audiometric="" tests.="" some="" commenters="" were="" concerned="" that="" physicians="" may="" not="" have="" the="" specific="" knowledge="" necessary="" to="" conduct="" audiometric="" testing.="" one="" of="" these="" commenters="" stated="" that:="" *="" *="" *="" many="" physicians="" are="" not="" well="" versed="" in="" problems="" of="" audition,="" especially="" occupational="" noise="" induced="" hearing="" loss="" [nihl].="" if="" physicians="" are="" to="" be="" included="" in="" the="" list="" of="" acceptable="" supervisors,="" they="" should="" be="" limited="" to="" ``qualified="" occupational="" physicians,''="" or="" perhaps="" ``qualified="" occupational="" physicians="" with="" audiological="" experience.''="" other="" commenters="" recognized="" that="" technicians="" need="" specific="" training,="" but="" disagreed="" as="" to="" whether="" formal="" certification="" was="" necessary.="" many="" commenters="" specifically="" stated="" that="" msha="" should="" require="" caohc="" certification="" as="" the="" minimum="" acceptable="" criteria="" for="" training="" of="" audiometric="" technicians.="" many="" commenters="" specifically="" recommended="" or="" implied="" that="" msha="" treat="" technicians="" who="" operate="" microprocessor="" audiometers="" the="" same="" as="" technicians="" who="" operate="" other="" types="" of="" audiometers.="" one="" stated="" that:="" the="" use="" of="" a="" microprocessor="" audiometer="" does="" not="" guarantee="" a="" valid,="" reliable="" audiogram,="" nor="" does="" it="" obviate="" the="" need="" for="" the="" technician="" to="" be="" familiar="" with="" the="" important="" interpersonal="" and="" procedural="" details="" of="" administering="" an="" audiogram="" and="" providing="" feedback="" to="" the="" employees.="" other="" commenters,="" however,="" stated="" that="" persons="" who="" operate="" microprocessors="" do="" not="" need="" to="" be="" certified,="" but="" it="" was="" unclear="" whether="" they="" thought="" that="" training="" and="" demonstration="" of="" competency="" would="" be="" necessary="" for="" such="" technicians.="" finally="" one="" commenter="" wanted="" ``maximum="" flexibility="" in="" audiometric="" testing.''="" one="" commenter="" on="" this="" issue="" stated="" that:="" *="" *="" *="" we="" do="" not="" believe="" that="" there="" are="" other="" qualified="" medical="" personnel="" [other="" than="" an="" audiologist="" or="" physician]="" who="" understand="" the="" principles="" of="" interpreting="" an="" audiogram="" appropriately.="" the="" u.s.="" army="" (1991),="" air="" force="" (1991),="" and="" navy="" (1994)="" regulations="" require="" that="" a="" physician,="" audiologist="" or="" technician="" conduct="" the="" audiometric="" tests.="" the="" audiometric="" technician="" must="" be="" caohc="" certified="" or="" certified="" through="" military="" medical="" training="" and="" be="" under="" the="" supervision="" of="" a="" physician="" or="" audiologist.="" msha="" believes="" that="" it="" is="" unnecessary="" to="" specify="" that="" physicians="" be="" ``licensed''="" or="" ``qualified.''="" all="" states="" require="" physicians="" to="" be="" licensed.="" msha="" is="" concerned,="" however,="" that="" licensing="" does="" not="" imply="" qualification="" to="" conduct="" audiometric="" testing,="" evaluate="" audiograms,="" and="" supervise="" technicians="" in="" these="" areas.="" the="" agency="" expects="" physicians="" to="" exercise="" professional="" judgement="" when="" evaluating="" their="" own="" qualifications="" to="" conduct="" audiometric="" testing.="" in="" addition,="" the="" medical="" profession="" enforces="" a="" high="" degree="" of="" accountability="" and="" ethical="" standards.="" nevertheless,="" further="" comment="" is="" requested="" on="" this="" issue.="" msha="" believes="" that="" certification="" or="" licensing="" of="" audiologists="" is="" essential="" to="" an="" effective="" hcp.="" properly="" trained="" and="" certified="" audiologists="" would="" be="" qualified="" to="" conduct="" audiometric="" testing,="" evaluate="" audiograms,="" and="" supervise="" technicians.="" unlike="" physicians,="" msha="" believes="" that="" certification="" or="" licensing="" presupposes="" that="" the="" audiologist="" would="" be="" qualified="" to="" conduct="" audiometric="" testing.="" with="" respect="" to="" qualified="" technicians,="" msha="" considered="" the="" comments="" on="" this="" topic="" filed="" in="" response="" to="" the="" anprm="" and="" concluded="" that="" qualified="" technicians="" need="" to="" be="" certified="" by="" caohc="" or="" by="" an="" organization="" offering="" equivalent="" training.="" caohc="" or="" equivalent="" certification="" would="" assure="" that="" the="" technicians="" are="" qualified.="" while="" msha="" recognizes="" that="" the="" osha="" standard="" allows="" physicians="" discretion="" to="" judge="" the="" qualifications="" of="" technicians,="" msha="" believes="" requiring="" certification="" is="" not="" restrictive="" and="" best="" ensures="" quality="" control.="" msha="" would="" also="" require="" caohc="" or="" equivalent="" certification="" for="" technicians="" who="" operate="" microprocessor="" audiometers.="" the="" agency="" concludes="" that="" requiring="" caohc="" or="" equivalent="" certification="" would="" not="" be="" overly="" burdensome="" on="" the="" mining="" industry.="" niosh="" commented="" on="" osha's="" proposed="" rule,="" and="" again="" on="" msha's="" anprm,="" that="" there="" may="" not="" be="" enough="" caohc="" courses="" offered="" in="" a="" given="" year,="" or="" in="" a="" wide="" enough="" geographical="" area,="" to="" require="" that="" all="" technicians="" be="" caohc="" certified.="" osha's="" preamble="" (46="" fr="" 4128)="" in="" 1981="" indicated="" that,="" at="" that="" time,="" there="" were="" about="" 6,700="" caohc="" certified="" technicians="" and="" 700="" course="" directors.="" since="" 1981,="" however,="" the="" number="" of="" caohc="" course="" directors="" has="" decreased="" to="" about="" 400,="" but="" the="" number="" of="" certified="" technicians="" has="" increased="" to="" about="" 14,000.="" although="" this="" number="" of="" certified="" technicians="" may="" be="" sufficient="" to="" conduct="" the="" required="" audiograms="" in="" the="" mining="" industry,="" msha="" believes="" that="" promulgation="" of="" this="" rule="" will="" result="" in="" even="" more="" individuals="" seeking="" certification.="" in="" addition="" to="" caohc="" certification="" for="" audiometric="" technicians,="" msha="" would="" also="" accept="" training="" by="" any="" other="" recognized="" organization="" offering="" equivalent="" certification.="" msha="" requests="" information="" on="" any="" other="" nationally="" recognized="" program="" for="" the="" certification="" of="" persons="" to="" conduct="" audiometric="" tests.="" msha="" also="" considered="" the="" ``qualifications="" of="" personnel''="" requirements="" from="" u.s.="" armed="" forces="" codes="" and="" international="" standards.="" the="" consensus="" was="" that="" the="" technician="" needed="" to="" be="" trained="" in="" conducting="" audiometric="" testing.="" although="" the="" proposal="" would="" not="" require="" that="" the="" audiologist="" or="" physician="" be="" present="" when="" the="" technician="" conducts="" the="" audiometric="" test,="" msha="" would="" require="" that="" they="" directly="" supervise="" the="" technician="" to="" ensure="" strict="" adherence="" to="" testing="" procedures="" and="" measurement="" parameters.="" baseline="" audiogram="" section="" 62.140(b)="" of="" msha's="" proposal="" would="" require="" that,="" within="" six="" months="" of="" a="" miner's="" enrollment="" in="" an="" hcp,="" the="" miner="" shall="" be="" offered="" a="" valid="" baseline="" audiogram="" of="" the="" miner's="" hearing="" acuity="" against="" which="" subsequent="" annual="" audiograms="" can="" be="" compared.="" this="" would="" include="" miners="" with="" temporary="" layoffs,="" such="" as="" those="" miners="" employed="" at="" seasonal="" operations.="" however,="" the="" proposal="" would="" allow="" up="" to="" 12="" months="" [[page="" 66433]]="" to="" obtain="" a="" baseline="" audiogram="" when="" a="" mobile="" test="" van="" is="" used.="" under="" existing="" standards="" for="" coal="" mines,="" msha="" does="" not="" specifically="" address="" a="" time="" frame="" for="" offering="" a="" baseline="" audiogram="" for="" those="" miners="" under="" a="" hearing="" conservation="" plan.="" msha="" has="" no="" requirements="" for="" baseline="" audiograms="" in="" its="" current="" metal="" and="" nonmetal="" noise="" regulation.="" this="" proposal="" is="" consistent="" with="" osha's="" noise="" regulation.="" the="" proposal="" would="" allow="" mine="" operators="" to="" use="" existing="" audiograms="" as="" the="" baseline,="" provided="" that="" they="" meet="" the="" testing="" requirements="" of="" this="" part.="" osha="" also="" accepts="" existing="" audiograms="" as="" a="" baseline="" because,="" in="" most="" cases,="" accepting="" old="" baseline="" audiograms="" is="" more="" protective="" for="" the="" employee.="" osha="" reasoned="" that:="" *="" *="" *="" old="" baselines="" will="" allow="" the="" true="" extent="" of="" the="" hearing="" loss="" over="" the="" years="" to="" be="" evaluated.="" obtaining="" a="" new="" baseline="" audiogram="" after="" many="" years="" of="" noise="" exposure="" might="" be="" less="" protective="" since="" the="" new="" audiogram="" might="" show="" higher="" thresholds="" and="" the="" true="" extent="" of="" future="" losses="" would="" appear="" smaller="" than="" when="" compared="" with="" the="" original="" baseline.="" all="" commenters,="" addressing="" the="" issue="" of="" audiograms="" recognized="" the="" need="" to="" establish="" a="" baseline.="" the="" commenters="" varied,="" however,="" on="" the="" time="" needed="" to="" establish="" this="" baseline,="" i.e.,="" from="" 30="" days="" up="" to="" one="" year="" from="" the="" first="" exposure="" to="" noise.="" one="" stated="" that="" ``*="" *="" *="" the="" first="" annual="" or="" periodic="" audiogram="" should="" be="" allowed="" to="" be="" considered="" as="" the="" baseline="" or="" pre-employment="" audiogram.''="" most="" of="" the="" commenters,="" who="" specified="" a="" time="" frame="" for="" completing="" the="" baseline="" audiogram,="" agreed="" with="" osha's="" position="" of="" allowing="" up="" to="" six="" months.="" only="" one="" comment="" was="" received,="" on="" the="" 1-year="" time="" allowed,="" for="" audiometric="" testing="" with="" mobile="" test="" vans.="" this="" commenter="" was="" concerned="" that="" miners="" might="" be="" exposed="" to="" noise,="" in="" the="" interim="" period,="" until="" the="" test="" van="" was="" available="" and="" recommended="" ``that="" the="" employees="" utilize="" hearing="" protection="" from="" the="" time="" they="" are="" enrolled="" in="" an="" hcp.''="" niosh="" (1995)="" recommended="" that="" the="" baseline="" audiogram="" be="" conducted="" within="" 30="" days="" of="" enrollment="" in="" an="" hcp,="" even="" if="" a="" mobile="" test="" van="" is="" used.="" niosh="" believes="" it="" is="" unacceptable="" to="" wait="" up="" to="" six="" months="" for="" a="" baseline="" audiogram,="" because="" exposure="" to="" high="" sound="" levels="" for="" a="" relatively="" short="" period="" of="" time="" can="" adversely="" affect="" the="" hearing="" acuity="" of="" susceptible="" individuals.="" msha="" has="" also="" taken="" into="" consideration="" requirements="" of="" the="" u.s.="" armed="" forces="" and="" the="" international="" community="" with="" respect="" to="" baseline="" audiograms.="" many="" in="" the="" international="" community="" and="" the="" u.s.="" armed="" services="" agree="" that="" the="" baseline="" audiogram="" is="" of="" primary="" importance.="" msha="" has="" determined="" that="" the="" baseline="" audiogram="" is="" essential,="" because="" it="" is="" the="" reference="" against="" which="" subsequent="" audiograms="" are="" to="" be="" compared.="" the="" comparison="" will="" be="" used="" to="" determine="" the="" extent="" of="" hearing="" loss.="" if="" the="" baseline="" audiometric="" test="" is="" not="" conducted="" properly,="" it="" will="" not="" reflect="" the="" miner's="" true="" hearing="" thresholds="" and="" any="" changes="" between="" baseline="" and="" subsequent="" tests="" may="" be="" masked.="" further,="" existing="" audiograms="" may="" be="" used="" as="" the="" baseline,="" if="" they="" meet="" the="" testing="" requirements="" of="" this="" part.="" the="" use="" of="" pre-existing="" audiograms="" would="" be="" more="" protective="" for="" the="" affected="" miner="" and="" less="" burdensome="" on="" the="" mine="" operator.="" because="" of="" the="" baseline="" audiogram's="" importance,="" it="" is="" critical="" to="" obtain="" one="" before="" exposure="" to="" hazardous="" noise.="" if="" this="" is="" not="" possible,="" then="" the="" baseline="" is="" to="" be="" obtained="" as="" soon="" as="" is="" reasonably="" possible.="" due="" to="" remote="" locations="" and="" intermittent="" operations="" of="" many="" mines,="" msha="" determined="" that="" allowing="" six="" months="" (or="" 12="" months="" if="" a="" mobile="" test="" van="" is="" used)="" for="" obtaining="" the="" baseline="" audiogram="" was="" reasonable.="" the="" 12="" month="" period="" would="" allow="" mine="" operators="" to="" schedule="" many="" baseline="" and="" annual="" audiograms="" simultaneously,="" and="" thus,="" substantially="" reduce="" the="" cost="" when="" mobile="" test="" vans="" are="" used.="" it="" should="" be="" noted="" that="" the="" provisions="" of="" sec.="" 62.120="" of="" msha's="" proposal="" would="" require="" mine="" operators="" to="" ensure="" that="" all="" miners="" enrolled="" in="" a="" hearing="" conservation="" program="" be="" provided="" hearing="" protectors="" until="" they="" receive="" a="" baseline="" audiogram;="" and="" require="" the="" operator="" to="" ensure="" the="" protection="" is="" used="" if="" the="" need="" to="" wait="" for="" a="" mobile="" test="" van="" delays="" the="" initial="" audiogram="" past="" 6="" months.="" msha="" solicits="" additional="" comments="" on="" the="" appropriate="" time="" frame="" for="" obtaining="" audiograms,="" especially="" in="" remote="" mining="" areas.="" 14-hour="" quiet="" period="" section="" 62.140(b)(2)="" of="" the="" proposal="" would="" require="" that="" the="" mine="" operator="" ensure="" that="" the="" affected="" miner="" is="" not="" exposed="" to="" workplace="" noise="" for="" at="" least="" a="" 14-hour="" period="" immediately="" prior="" to="" receiving="" the="" baseline="" audiogram.="" msha="" has="" no="" existing="" requirement="" in="" this="" area.="" the="" proposal="" is="" similar="" to="" osha's="" noise="" standard="" except="" that,="" as="" discussed="" below,="" osha="" permits="" the="" use="" of="" hearing="" protectors="" in="" lieu="" of="" removal="" from="" workplace="" noise.="" the="" 14-hour="" quiet="" period="" is="" intended="" to="" provide="" a="" miner's="" hearing="" with="" sufficient="" rest="" to="" allow="" recovery="" from="" any="" temporary="" threshold="" shift="" (tts)="" caused="" by="" pre-test="" noise="" exposure.="" if="" the="" baseline="" audiogram="" is="" skewed="" by="" tts,="" subsequent="" comparisons="" to="" annual="" audiograms="" would="" not="" provide="" accurate="" indications="" of="" the="" extent="" of="" damage="" incurred="" during="" the="" time="" span="" between="" the="" baseline="" and="" subsequent="" tests.="" there="" were="" numerous="" comments="" concerning="" the="" time="" frame="" for="" a="" quiet="" period.="" of="" these,="" most="" suggested="" that="" the="" 14="" hours="" mandated="" in="" osha's="" noise="" standard="" was="" sufficient="" to="" minimize="" any="" tts.="" others="" recommended="" different="" time="" frames="" for="" the="" quiet="" period.="" one="" stated="" that="" ``*="" *="" *="" there="" are="" sufficient="" human="" data="" in="" the="" literature="" to="" establish="" that="" a="" 14-hour="" quiet="" period="" is="" too="" short.''="" several="" commented="" that:="" a="" suitable="" quiet="" period="" of="" 24="" hours="" prior="" to="" the="" performance="" of="" audiometric="" testing="" would="" be="" preferred.="" however,="" a="" 16-hour="" quiet="" period="" would="" often="" meet="" the="" needs="" of="" most="" operations,="" being="" the="" amount="" of="" time="" normally="" between="" the="" end="" of="" one="" days="" work="" and="" starting="" time="" for="" the="" next.="" one="" thought="" that="" eight="" hours="" was="" enough.="" another="" commented="" that="" a="" quiet="" period="" should="" be="" allowed="" but="" not="" required="" for="" the="" initial="" test.="" further,="" this="" commenter="" stated="" that="" 24="" hours="" should="" be="" required="" for="" confirmation="" testing.="" fodor="" and="" oleinick="" (1986)="" in="" their="" paper="" on="" workers'="" compensation="" reported="" that="" one="" researcher="" found="" full="" recovery="" from="" ``physiological="" fatigue''="" in="" 16="" hours,="" with="" recovery="" from="" ``pathological="" fatigue''="" taking="" longer.="" this="" researcher="" reported="" that="" the="" initial="" recovery="" seems="" to="" be="" a="" logarithmic="" function="" of="" time="" and="" the="" longer="" recovery="" period="" is="" a="" linear="" function.="" most="" researchers,="" however,="" report="" complete="" recovery="" from="" tts="" taking="" no="" longer="" than="" 16="" hours="" provided="" the="" tts="" did="" not="" exceed="" 40="" db.="" on="" the="" other="" hand,="" some="" states="" require="" that="" a="" worker="" be="" away="" from="" noise="" exposure="" for="" six="" months="" before="" evaluating="" hearing="" loss="" for="" workers'="" compensation="" purposes.="" msha="" concludes,="" after="" reviewing="" the="" scientific="" literature="" and="" the="" standards="" of="" various="" jurisdictions,="" that="" the="" length="" of="" time="" required="" to="" obtain="" full="" recovery="" from="" tts="" depends="" upon="" the="" magnitude="" of="" the="" sound="" pressure="" level,="" the="" length="" of="" exposure,="" the="" frequencies="" affected,="" the="" person's="" age,="" and="" the="" person's="" susceptibility="" to="" hearing="" damage.="" because="" the="" mine="" operator="" has="" no="" control="" over="" the="" non-occupational="" noise="" exposure="" of="" a="" miner,="" msha="" decided="" against="" limiting="" non-="" occupational="" noise="" to="" a="" specified="" sound="" level="" during="" the="" quiet="" period;="" however,="" as="" noted="" below,="" msha="" is="" requiring="" that="" the="" mine="" operator="" notify="" employees="" of="" the="" need="" to="" avoid="" high="" levels="" of="" noise="" during="" the="" 14-hour="" period="" preceding="" the="" test,="" which="" it="" [[page="" 66434]]="" hopes="" will="" limit="" non-occupational="" noise="" exposure.="" with="" the="" exception="" of="" the="" eec="" (15="" minute="" quiet="" period),="" the="" consensus="" of="" the="" international="" community="" and="" the="" u.s.="" armed="" services="" is="" that="" there="" should="" be="" a="" quiet="" period="" of="" at="" least="" 14="" hours.="" msha="" decided="" that="" a="" 14-hour="" quiet="" period="" would="" be="" the="" most="" appropriate="" alternative="" and="" is="" consistent="" with="" osha's="" requirements,="" comments="" to="" the="" anprm,="" and="" its="" review="" of="" available="" literature.="" a="" quiet="" period="" longer="" than="" 14="" hours="" could="" place="" an="" undue="" burden="" on="" mine="" operators="" as="" the="" miner="" may="" have="" to="" stay="" away="" from="" work="" to="" comply="" with="" the="" quiet="" period="" if="" the="" miner="" works="" a="" slightly="" extended="" shift;="" many="" work="" shifts="" exceed="" 8="" hours="" especially="" when="" a="" lunch="" period="" is="" taken="" into="" account.="" use="" of="" hearing="" protectors="" for="" 14-hour="" quiet="" periods="" section="" 62.140(b)(2)="" of="" the="" proposed="" standard="" would="" also="" prohibit="" the="" use="" of="" hearing="" protectors="" as="" a="" substitute="" for="" the="" 14-hour="" quiet="" period.="" as="" noted="" previously,="" osha="" currently="" does="" allow="" hearing="" protectors="" to="" be="" used="" during="" the="" required="" 14-hour="" quiet="" period.="" when="" it="" first="" promulgated="" its="" hearing="" conservation="" amendment="" in="" 1981,="" osha="" did="" not="" permit="" the="" substitution="" of="" hearing="" protectors="" for="" the="" 14-hour="" quiet="" period.="" this="" decision="" generated="" much="" discussion="" among="" commenters="" believing="" that="" it="" was="" unnecessarily="" restrictive.="" even="" professional="" audiologists="" strongly="" disagreed="" on="" this="" issue.="" one="" commenter="" suggested="" that="" if="" the="" hearing="" protector="" reduced="" the="" level="" of="" sound="" energy="" reaching="" the="" ear="" to="" 80="" dba="" or="" less,="" this="" would="" effectively="" reduce="" the="" amount="" of="" baseline="" contamination="" to="" less="" than="" the="" usual="" amount="" of="" audiometric="" measurement="" error.="" commenters="" also="" cited="" problems="" such="" as="" additional="" overtime="" wages,="" disruptions="" of="" work="" schedules,="" and="" non-occupational="" noise="" exposure.="" in="" 1983,="" osha="" revised="" its="" hearing="" conservation="" amendment="" to="" allow="" the="" use="" of="" hearing="" protectors="" as="" an="" alternative="" for="" the="" 14-hour="" quiet="" period="" prior="" to="" the="" baseline="" audiogram.="" osha="" concurred="" with="" the="" large="" number="" of="" commenters="" who="" testified="" that="" the="" use="" of="" hearing="" protectors="" may="" provide="" sufficient="" attenuation="" to="" prevent="" noise-induced="" tts="" from="" contaminating="" baseline="" audiograms.="" msha="" received="" many="" comments="" addressing="" this="" issue.="" several="" of="" these="" stated="" that="" hearing="" protectors="" should="" not="" be="" substituted="" for="" the="" quiet="" period.="" their="" general="" consensus="" can="" be="" summarized="" by="" one="" commenter="" who="" stated="" that:="" *="" *="" *="" the="" use="" of="" hpds="" cannot="" be="" relied="" upon="" to="" reduce="" the="" noise="" in="" all="" cases="" to="" a="" level="" suitable="" to="" be="" considered="" quiet="" for="" the="" purpose="" of="" establishing="" baseline="" audiograms,="" especially="" if="" individual="" variations="" in="" susceptibility="" to="" noise="" induced="" hearing="" loss="" are="" considered.="" other="" commenters="" believed="" that="" the="" use="" of="" hearing="" protectors="" should="" be="" allowed="" because="" they="" prevent="" tts.="" one="" such="" commenter="" wanted="" a="" qualification="" stating="" that:="" *="" *="" *="" in="" many="" instances="" it="" may="" simply="" not="" be="" practical="" or="" possible="" to="" test="" everyone="" for="" their="" baselines="" as="" they="" come="" to="" the="" workshift,="" and="" thus="" reliance="" on="" hpds="" for="" the="" 14-hr.="" noise-free="" period="" is="" required.="" thus="" msha="" should="" allow="" use="" of="" hpds="" in="" lieu="" of="" the="" 14="" hrs.,="" but="" with="" the="" following="" stipulation:="" *="" *="" *="" no="" more="" than="" five="" days="" prior="" to="" the="" test,="" 1)="" the="" employees="" whose="" hearing="" is="" to="" be="" evaluated="" receive="" refresher="" training="" in="" the="" use="" of="" their="" protectors,="" and="" 2)="" the="" condition="" of="" the="" hearing="" protector(s)="" the="" employee="" is="" to="" wear="" is="" checked="" and="" found="" satisfactory.="" any="" employee="" whose="" twa="" exceeds="" 100="" dba="" shall="" be="" required="" to="" wear="" an="" earplug="" together="" with="" an="" earmuff="" *="" *="" *="" some="" researchers,="" shaw="" (1985)="" and="" suter="" (1983),="" contend="" that="" sound="" levels="" must="" be="" below="" 72="" dba="" to="" be="" considered="" ``effective="" quiet.''="" schwetz="" et="" al.="" (1980)="" found="" that="" a="" sound="" level="" below="" 85="" dba="" is="" needed="" for="" recovery="" of="" tts.="" individuals="" with="" tts="" recovered="" their="" normal="" hearing="" quicker="" when="" exposed="" to="" 75="" dba="" sound="" level="" rather="" than="" 85="" dba.="" the="" niosh="" criteria="" document="" (1972)="" recommends="" a="" sound="" pressure="" level="" of="" 65="" db="" as="" ``effective="" quiet''="" based="" on="" work="" by="" schmidek="" et="" al="" (1972).="" hodge="" and="" price="" (1978)="" concluded="" that="" the="" level="" would="" have="" to="" fall="" below="" 60="" dba="" to="" be="" effective="" quiet="" and="" not="" contribute="" to="" the="" development="" of="" a="" tts.="" msha's="" proposal="" differs="" from="" osha's="" standard,="" in="" that="" it="" would="" not="" allow="" hearing="" protectors="" to="" be="" substituted="" for="" the="" 14-hour="" quiet="" period="" prior="" to="" the="" baseline="" audiogram.="" although="" msha="" recognizes="" that="" its="" decision="" may="" pose="" some="" scheduling="" problems="" for="" mine="" operators,="" it="" should="" be="" emphasized="" that="" the="" quiet="" period="" is="" required="" only="" for="" the="" baseline="" audiogram.="" mine="" operators,="" however,="" may="" choose="" to="" employ="" it="" for="" the="" annual="" audiograms.="" msha="" has="" determined="" that="" the="" problems="" associated="" with="" the="" use="" of="" individual="" hearing="" protectors="" are="" too="" great="" to="" guarantee="" an="" accurate="" baseline="" measurement.="" data="" indicate="" that="" in="" order="" to="" provide="" effective="" quiet,="" the="" sound="" levels="" encountered="" during="" the="" quiet="" period="" would="" need="" to="" be="" below="" 80="" dba.="" msha="" is="" particularly="" concerned="" with="" the="" ability="" of="" hearing="" protectors="" to="" attenuate="" noise="" to="" such="" low="" levels="" in="" order="" to="" prevent="" contamination="" of="" the="" baseline.="" even="" at="" 80="" dba,="" some="" researchers="" concluded="" that="" this="" level="" may="" be="" inadequate="" for="" the="" most="" susceptible="" individuals.="" moreover,="" the="" typical="" sound="" levels="" in="" mining="" are="" higher="" than="" those="" experienced="" in="" general="" industry;="" therefore,="" hearing="" protectors="" would="" need="" to="" attenuate="" the="" noise="" to="" a="" greater="" degree.="" although="" msha="" contends="" that="" hearing="" protectors="" can="" provide="" some="" protection="" to="" miners="" whose="" exposures="" do="" not="" exceed="" the="" pel,="" msha="" has="" concluded="" that="" engineering="" and="" administrative="" controls="" provide="" much="" more="" effective="" protection.="" msha's="" concerns="" with="" the="" ability="" of="" hearing="" protectors="" to="" provide="" adequate="" attenuation="" are="" addressed="" in="" connection="" with="" the="" requirements="" of="" proposed="" sec.="" 62.120(b),="" under="" the="" heading="" of="" hearing="" protector="" effectiveness.="" notification="" to="" avoid="" high="" sound="" levels="" section="" 62.140(b)(3)="" of="" the="" proposal="" would="" require="" mine="" operators="" to="" notify="" miners="" to="" avoid="" high="" levels="" of="" non-occupational="" noise="" during="" the="" 14-hour="" period="" before="" taking="" the="" baseline="" audiogram.="" this="" requirement="" is="" the="" same="" as="" osha's="" noise="" standard.="" in="" the="" 1983="" preamble="" to="" its="" hearing="" conservation="" amendment="" (48="" fr="" 9757),="" osha="" emphasizes="" that,="" even="" if="" workers="" received="" this="" information="" in="" training="" classes,="" such="" notification="" would="" aid="" memory="" and,="" thus,="" provide="" additional="" support="" to="" the="" goal="" of="" obtaining="" a="" valid="" baseline="" audiogram.="" osha="" concludes="" its="" discussion="" of="" this="" issue="" as="" follows:="" although="" employers="" are="" not="" responsible="" for="" employee="" noise="" exposures="" sustained="" away="" from="" the="" workplace,="" the="" likelihood="" of="" non-="" occupational="" noise="" exposure="" contaminating="" the="" baseline="" audiogram="" can="" be="" substantially="" reduced="" by="" counseling="" workers="" of="" the="" need="" to="" avoid="" such="" exposures="" in="" the="" period="" before="" their="" baseline="" test.="" therefore,="" this="" requirement="" is="" necessary="" and="" appropriate="" for="" the="" implementation="" of="" a="" successful="" hearing="" conservation="" program.="" only="" a="" few="" commenters="" offered="" an="" opinion="" on="" this="" specific="" issue="" in="" response="" to="" msha's="" anprm.="" these="" commenters="" agreed="" that="" workers="" need="" to="" be="" advised="" to="" avoid="" non-occupational="" noise="" exposure="" prior="" to="" taking="" the="" baseline="" audiogram.="" msha="" believes="" that="" it="" is="" appropriate="" for="" operators="" to="" notify="" miners="" of="" the="" importance="" of="" avoiding="" high="" noise="" areas="" in="" order="" to="" obtain="" valid="" baseline="" audiograms.="" the="" proposed="" requirement="" is="" consistent="" with="" osha's="" noise="" standard="" and="" the="" limited="" commenter="" responses.="" annual="" audiogram="" section="" 62.140(c)="" of="" msha's="" proposal="" requires="" that,="" after="" establishing="" a="" baseline,="" the="" miner="" to="" be="" offered="" a="" new="" [[page="" 66435]]="" audiogram="" once="" every="" 12="" months="" as="" long="" as="" the="" miner="" remains="" in="" the="" hcp.="" existing="" msha="" standards="" require="" coal="" mine="" operators="" to="" submit="" a="" hearing="" conservation="" plan,="" which="" includes="" conducting="" periodic="" audiograms,="" for="" each="" miner="" exposed="" to="" noise="" in="" excess="" of="" the="" pel.="" because="" the="" use="" of="" hearing="" protectors="" is="" considered="" to="" provide="" compliance="" with="" the="" pel="" in="" this="" industry,="" few="" receive="" audiograms.="" moreover,="" there="" are="" no="" standards="" requiring="" audiograms="" for="" metal="" and="" nonmetal="" workers.="" osha="" requires,="" after="" the="" baseline="" audiogram="" has="" been="" obtained,="" an="" annual="" audiogram="" for="" each="" employee="" exposed="" at="" or="" above="" its="" action="" level="" to="" identify="" changes="" in="" hearing="" acuity,="" so="" that="" the="" use="" of="" hearing="" protectors="" can="" be="" prescribed="" or="" other="" follow-up="" measures="" initiated="" before="" hearing="" loss="" progresses.="" the="" preamble="" to="" osha's="" hearing="" conservation="" amendment="" (46="" fr="" 4143)="" states:="" osha="" has="" chosen="" to="" retain="" the="" annual="" audiometric="" test="" requirement="" because="" of="" the="" potential="" seriousness="" of="" the="" hearing="" damage="" that="" can="" occur="" within="" a="" 2-year="" period.="" for="" employees="" exposed="" to="" high="" levels="" of="" noise,="" a="" 2-year="" period="" between="" audiograms="" might="" allow="" too="" much="" hearing="" loss="" to="" occur="" before="" identifying="" the="" loss="" and="" taking="" remedial="" steps.="" in="" response="" to="" its="" anprm,="" msha="" received="" numerous="" comments="" that="" specifically="" addressed="" periodic="" audiograms.="" many="" of="" these="" supported="" annual="" testing="" and="" a="" few="" recommended="" a="" different="" time="" period.="" these="" latter="" commenters="" suggested="" the="" following="" alternative="" time="" periods:="" once="" or="" twice="" a="" year,="" depending="" on="" the="" intensity="" of="" the="" exposure;="" every="" other="" year;="" and="" based="" upon="" need.="" msha="" concludes="" that="" the="" determination="" of="" an="" sts="" in="" the="" one-year="" period="" between="" required="" audiograms="" is="" meaningful="" for="" detecting="" the="" type="" of="" problems="" for="" which="" hcp="" enrollment="" is="" the="" purpose.="" detection="" of="" an="" sts="" triggers="" several="" important="" actions="" under="" the="" proposal.="" retraining="" of="" the="" miner="" would="" be="" required.="" if="" the="" miner="" is="" enrolled="" in="" the="" hcp="" as="" a="" result="" of="" noise="" exposure="" above="" the="" action="" level,="" but="" the="" miner's="" noise="" exposure="" is="" below="" the="" pel,="" detection="" of="" an="" sts="" would="" require="" the="" provision="" of="" a="" hearing="" protector--which="" a="" miner="" at="" that="" exposure="" level="" would="" otherwise="" not="" be="" required="" to="" utilize.="" if="" the="" miner="" was="" already="" using="" a="" hearing="" protector,="" it="" would="" have="" to="" be="" replaced.="" detection="" of="" an="" sts="" would="" also="" require="" reevaluation="" of="" the="" engineering="" and="" administrative="" controls="" being="" used.="" waiting="" two="" years="" or="" more="" between="" periodic="" audiograms="" could="" allow="" excessive="" hearing="" damage="" to="" miners.="" msha="" also="" recognizes="" that="" some="" miners="" may="" be="" more="" susceptible="" to="" hearing="" damage="" from="" noise="" exposure,="" and="" a="" few="" may="" be="" exposed="" to="" high="" sound="" levels,="" such="" that="" annual="" audiometric="" testing="" may="" not="" be="" frequent="" enough="" to="" prevent="" an="" sts.="" in="" light="" of="" the="" comments="" to="" msha's="" anprm,="" the="" agency's="" review="" of="" the="" literature="" and="" pertinent="" governmental="" regulations,="" and="" osha's="" existing="" requirements,="" msha="" has="" tentatively="" concluded="" that="" annual="" audiometric="" testing="" is="" both="" necessary="" and="" appropriate.="" annual="" audiometric="" testing="" is="" an="" integral="" part="" of="" a="" comprehensive="" hcp.="" supplemental="" baseline="" section="" 62.140(d)="" of="" msha's="" proposal="" would="" require="" the="" mine="" operator="" to="" establish="" a="" ``supplemental="" audiogram''="" when:="" (1)="" the="" sts="" revealed="" by="" the="" annual="" audiogram="" is="" persistent,="" or="" (2)="" the="" hearing="" threshold="" shown="" in="" the="" annual="" audiogram="" indicates="" significant="" improvement="" over="" the="" baseline="" audiogram.="" these="" proposed="" requirements="" are="" similar="" to="" those="" in="" osha's="" noise="" standard="" except="" for="" the="" terminology.="" in="" response="" to="" its="" anprm,="" msha="" received="" numerous="" comments="" on="" circumstances="" in="" which="" it="" was="" not="" appropriate="" to="" use="" the="" original="" baseline="" audiogram.="" many="" commenters="" were="" in="" favor="" of="" revising="" the="" baseline="" if="" an="" sts="" was="" persistent.="" one="" stressed="" the="" need="" for="" clear="" guidelines="" for="" baseline="" revision="" to="" avoid="" the="" use="" of="" a="" variety="" of="" creative="" methods="" which="" could="" result="" in="" different="" sts="" totals.="" other="" commenters="" were="" in="" favor="" of="" revising="" the="" baseline="" if="" the="" annual="" audiogram="" showed="" an="" improvement="" in="" hearing.="" another="" recommended="" revising="" the="" baseline="" only="" if="" the="" improvement="" was="" consistent="" for="" at="" least="" two="" or="" three="" consecutive="" tests.="" a="" final="" commenter="" wanted="" the="" baseline="" revised="" only="" if="" there="" was="" a="" testing="" error.="" msha="" believes,="" after="" reviewing="" these="" comments="" and="" standards="" of="" the="" u.s.="" armed="" forces,="" that="" revising="" the="" baseline="" after="" an="" sts="" has="" been="" identified="" would="" prevent="" this="" same="" sts="" from="" being="" identified="" repeatedly.="" the="" annual="" audiogram="" on="" which="" the="" sts="" is="" identified="" would="" then="" become="" the="" ``supplemental="" baseline="" audiogram.''="" this="" supplemental="" baseline="" would="" be="" used="" for="" comparison="" with="" future="" annual="" audiograms="" to="" identify="" a="" second="" sts.="" the="" ``baseline="" audiogram''="" would="" continue="" to="" be="" used="" to="" quantify="" the="" total="" hearing="" loss="" in="" determining="" whether="" the="" loss="" constitutes="" a="" ``reportable="" hearing="" loss''.="" to="" avoid="" confusion="" in="" the="" mining="" industry,="" msha="" is="" proposing="" the="" term="" ``supplemental="" baseline''="" rather="" than="" the="" term="" ``revised="" baseline''="" used="" under="" osha.="" since="" all="" audiograms="" are="" to="" be="" retained="" as="" part="" of="" the="" audiometric="" test="" record="" (see="" sec.="" 62.150(c)),="" supplementation="" of="" the="" baseline="" audiogram="" would="" not="" permit="" the="" destruction="" of="" the="" original="" baseline="" audiogram.="" msha="" would="" also="" require="" supplementation="" of="" the="" baseline="" if="" the="" annual="" audiogram="" shows="" significant="" improvement="" in="" hearing="" level="" because="" this="" would="" more="" closely="" resemble="" the="" miner's="" actual="" hearing="" acuity="" prior="" to="" being="" exposed="" to="" occupational="" noise.="" in="" this="" case,="" supplementation="" of="" the="" baseline="" would="" be="" more="" protective="" because="" it="" would="" allow="" more="" accurate="" evaluation="" of="" the="" true="" extent="" of="" future="" hearing="" loss.="" therefore,="" when="" a="" baseline="" is="" revised="" due="" to="" an="" improvement="" of="" hearing="" acuity,="" this="" supplemental="" baseline="" would="" be="" considered="" as="" the="" original="" baseline="" for="" determining="" when="" an="" sts="" occurs="" and="" for="" quantifying="" the="" total="" hearing="" loss="" for="" reportablility="" under="" part="" 50.="" the="" latter="" is="" reflected="" in="" the="" definition="" of="" reportable="" hearing="" loss.="" section="" 62.150="" audiometric="" test="" procedures="" msha="" proposes="" not="" to="" include="" specific="" procedural="" requirements="" for="" conducting="" audiometric="" tests,="" calibrating="" audiometers,="" and="" qualifying="" audiometric="" test="" rooms.="" instead,="" msha="" proposes="" a="" performance-oriented="" requirement="" that="" audiometric="" testing="" be="" conducted="" in="" accordance="" with="" scientifically="" validated="" procedures.="" msha="" would="" specify="" the="" test="" frequencies,="" but="" would="" allow="" the="" physician="" or="" the="" audiologist="" to="" use="" professional="" judgment="" in="" choosing="" the="" appropriate="" testing="" procedure(s)="" and="" require="" certification="" of="" the="" scientific="" validity="" of="" the="" procedures.="" while="" this="" approach="" may="" require="" somewhat="" more="" in="" the="" way="" of="" paperwork="" requirements,="" msha="" believes="" this="" is="" far="" preferable="" to="" the="" alternative="" of="" a="" detailed="" specification="" standard,="" which="" could="" stifle="" technology="" and="" impede="" improvements="" in="" methodology.="" the="" proposal="" would="" also="" specify="" what="" records="" must="" be="" maintained,="" and="" for="" how="" long,="" at="" the="" mine="" site.="" the="" proposed="" items="" included="" in="" the="" audiometric="" test="" record--name,="" job="" classification,="" audiograms="" and="" certifications="" as="" to="" the="" procedures="" used="" to="" take="" them,="" any="" exposure="" determinations,="" and="" the="" results="" of="" any="" follow-up="" examinations--would="" provide="" information="" essential="" for="" evaluating="" a="" miner's="" audiogram,="" among="" other="" purposes.="" [[page="" 66436]]="" the="" records="" are="" to="" be="" retained="" for="" at="" least="" six="" months="" beyond="" the="" duration="" of="" the="" miner's="" employment.="" the="" six="" month="" retention="" period="" at="" the="" mine="" site="" would="" assure="" that="" the="" audiometric="" test="" records="" of="" miners="" who="" have="" short="" periods="" of="" unemployment="" are="" not="" destroyed="" and="" are="" available="" for="" use="" by="" the="" mine="" operator="" to="" conduct="" further="" evaluations="" upon="" the="" miner's="" return.="" in="" practice,="" msha="" believes="" that="" many="" mine="" operators="" will="" keep="" miner's="" audiograms="" long="" after="" the="" miner's="" employment="" ceases,="" for="" use="" if="" the="" miner="" should="" file="" a="" subsequent="" workers'="" compensation="" claim="" for="" hearing="" loss.="" currently="" msha's="" metal="" and="" nonmetal="" noise="" standards="" do="" not="" contain="" audiometric="" testing="" provisions.="" while="" coal's="" noise="" standard="" requires="" audiometric="" testing,="" it="" does="" not="" specify="" how="" it="" is="" to="" be="" conducted.="" msha's="" proposal="" differs="" from="" osha's="" noise="" standard="" which="" contains="" detailed="" procedures="" in="" 29="" cfr="" sec.="" 1910.95(h)="" and="" the="" associated="" appendices="" c,="" d,="" and="" e.="" several="" commenters="" generally="" supported="" msha's="" adoption="" of="" audiometric="" testing="" requirements="" that="" are="" the="" same="" as="" osha's.="" a="" number="" of="" commenters="" made="" specific="" recommendations="" regarding="" various="" aspects="" of="" conducting="" audiograms="" including="" audiometric="" test="" instruments,="" calibration="" procedures,="" and="" audiometric="" test="" rooms.="" since="" msha="" has="" decided="" not="" to="" specify="" audiometric="" test="" requirements="" in="" the="" proposed="" rule,="" a="" discussion="" of="" the="" comments="" on="" specific="" procedures="" is="" not="" included="" (except="" in="" the="" section="" which="" follows,="" test="" procedures).="" ansi="" has="" several="" standards="" which="" impact="" the="" audiometric="" test="" procedure.="" ansi="" s3.21-1978="" ``methods="" for="" manual="" pure-tone="" threshold="" audiometry''="" provides="" detailed="" procedures="" for="" conducting="" audiometric="" tests.="" ansi="" s3.1-1991="" ``criteria="" for="" maximum="" ambient="" noise="" levels="" for="" audiometric="" test="" rooms''="" provides="" a="" criteria="" for="" the="" maximum="" background="" sound="" pressure="" levels="" neccessary="" in="" order="" to="" obtain="" a="" valid="" audiogram.="" ansi="" s3.6-1996="" ``specifications="" for="" audiommeters''="" provides="" design="" criteria="" for="" various="" classes="" of="" audiometers.="" after="" reviewing="" comments,="" the="" scientific="" literature="" and="" several="" governmental="" standards,="" msha="" chose="" not="" to="" include="" detailed,="" highly="" technical="" procedures="" and="" criteria="" for="" conducting="" audiometric="" testing="" in="" the="" proposal.="" instead="" msha="" chose="" a="" performance-oriented="" approach="" by="" proposing="" to="" require="" that="" audiometric="" testing="" procedures="" be="" governed="" by="" scientifically="" validated="" methods.="" because="" the="" person="" responsible="" for="" conducting="" the="" tests="" is="" a="" physician,="" audiologist,="" or="" qualified="" technician,="" he/she="" should="" be="" familiar="" with="" scientifically="" validated="" procedures.="" msha="" would="" allow="" the="" physician="" or="" the="" audiologist="" to="" use="" professional="" judgement="" in="" choosing="" the="" appropriate="" testing="" procedure(s).="" moreover,="" audiometer="" manufacturers="" provide="" recommendations="" on="" audiometer="" use="" and="" calibration="" (both="" laboratory="" and="" field).="" because="" the="" manufacturers="" are="" aware="" of="" the="" intricacies="" of="" their="" instruments,="" they="" would="" be="" the="" most="" qualified="" to="" issue="" recommendations="" on="" the="" use="" and="" calibration="" of="" their="" audiometers.="" by="" following="" manufacturer's="" recommendations="" accurate="" audiometric="" testing="" is="" assured="" without="" msha="" mandating="" detailed="" calibration="" specifications.="" by="" not="" specifying="" a="" single="" test="" procedure,="" msha="" would="" permit="" the="" use="" of="" any="" scientifically="" validated="" procedure.="" if="" a="" new,="" possibly="" more="" accurate="" procedure="" would="" be="" validated,="" the="" medical="" professional="" could="" readily="" adopt="" its="" use.="" if,="" however,="" current="" procedures="" were="" adopted="" in="" the="" rule,="" an="" amendment="" would="" be="" needed="" to="" permit="" the="" use="" of="" any="" new="" procedure.="" even="" though="" msha="" found="" no="" single="" comprehensive="" criteria="" for="" audiometric="" testing,="" save="" osha's,="" there="" are="" criteria="" which="" deal="" with="" various="" aspects="" of="" testing.="" for="" example,="" ansi="" has="" standards="" on="" background="" sound="" pressure="" levels="" for="" audiometric="" testing,="" methods="" for="" pure="" tone="" audiometry,="" and="" for="" specifications="" for="" audiometers.="" msha="" expects="" that="" most="" audiograms="" would="" be="" conducted="" using="" osha's="" requirements,="" since="" many="" physicians="" and="" audiologists="" are="" familiar="" with="" those="" regulations.="" further,="" many="" texts="" and="" caohc="" training="" courses="" discuss="" osha's="" audiometric="" testing="" procedures="" and="" criteria.="" although="" msha="" has="" not="" proposed="" detailed="" specifications="" in="" its="" standard,="" the="" agency="" contemplates="" publication="" of="" nonmandatory="" guidelines="" describing="" what="" it="" believes="" to="" be="" the="" latest="" scientific="" procedures="" for="" conducting="" audiometric="" tests.="" msha,="" realizing="" that="" performance-oriented="" standards="" for="" audiometric="" testing="" may="" be="" controversial,="" solicits="" comments="" on="" this="" approach,="" and="" continues="" to="" solicit="" comments="" on="" the="" audiometric="" test="" procedures,="" permissible="" background="" sound="" pressure="" levels,="" and="" calibration="" requirements="" for="" audiometers.="" test="" frequencies="" the="" proposal="" would="" require="" that="" audiometric="" tests="" be="" pure="" tone,="" air="" conduction,="" hearing="" threshold="" examinations,="" with="" test="" frequencies="" at="" 500,="" 1000,="" 2000,="" 3000,="" 4000,="" and="" 6000="" hz.="" the="" proposal="" also="" specifies="" that="" these="" examinations="" be="" taken="" separately="" for="" each="" ear="" at="" the="" given="" test="" frequencies.="" in="" response="" to="" msha's="" anprm,="" no="" commenters="" specifically="" addressed="" audiometric="" test="" frequencies.="" several,="" however,="" generally="" supported="" msha's="" adoption="" of="" audiometric="" testing="" requirements="" that="" are="" the="" same="" as="" osha's.="" msha's="" proposal="" would="" be="" consistent="" with="" osha's="" requirements="" with="" respect="" to="" testing="" frequencies,="" as="" well="" as="" consistent="" with="" the="" niosh="" criteria="" document="" (1972).="" although="" none="" of="" the="" commenters="" directly="" addressed="" audiometric="" test="" procedures,="" several="" stated="" that="" msha="" should="" adopt="" or="" follow="" the="" osha="" hearing="" conservation="" amendment.="" as="" noted="" in="" part="" ii="" of="" this="" preamble,="" noise-induced="" hearing="" loss="" is="" a="" permanent="" sensorineural="" condition="" that="" cannot="" be="" improved="" medically.="" it="" is="" characterized="" by="" a="" declining="" sensitivity="" to="" high="" frequency="" sounds.="" this="" loss="" usually="" appears="" first="" and="" is="" most="" severe="" at="" the="" 4000="" hz="" frequency.="" the="" ``4000="" hz="" notch''="" in="" the="" audiogram="" is="" typical="" of="" nihl.="" continued="" exposure="" causes="" the="" loss="" to="" include="" other="" audiometric="" test="" frequencies,="" with="" 500="" hz="" being="" the="" least="" affected.="" while="" 500,="" 1000,="" and="" 6000="" hz="" are="" not="" included="" in="" the="" definition="" of="" sts,="" msha,="" like="" osha,="" believes="" that="" these="" test="" frequencies="" contribute="" to="" a="" more="" complete="" audiometric="" profile="" and="" are="" helpful="" in="" assessing="" the="" validity="" of="" the="" audiogram="" as="" a="" whole.="" furthermore,="" the="" inclusion="" of="" 500="" and="" 1000="" hz="" makes="" it="" easier="" for="" an="" audiologist="" or="" physician="" to="" differentiate="" conductive="" hearing="" loss="" from="" nihl,="" and="" the="" inclusion="" of="" 6000="" hz="" would="" better="" differentiate="" between="" presbycusis="" and="" nihl.="" certification="" section="" 62.150(b)="" of="" msha's="" proposal="" would="" require="" that="" mine="" operators="" obtain="" a="" certification,="" from="" whomever="" conducts="" audiometric="" tests="" under="" this="" part,="" that="" such="" tests="" were="" conducted="" according="" to="" a="" scientifically="" validated="" procedure.="" osha's="" current="" noise="" standard="" does="" not="" require="" such="" certification.="" osha="" has="" specific="" audiological="" test="" procedures,="" allowable="" background="" sound="" pressure="" levels="" in="" audiometric="" test="" rooms,="" and="" audiometer="" calibration="" requirements.="" msha's="" metal="" and="" nonmetal="" noise="" standards="" do="" not="" contain="" audiometric="" testing="" provisions.="" while="" coal's="" noise="" standard="" requires="" audiometric="" testing,="" it="" does="" not="" specify="" how="" it="" is="" to="" be="" conducted.="" msha="" did="" not="" address="" this="" issue="" of="" certification="" in="" its="" anprm="" and,="" therefore,="" no="" comments="" were="" received.="" [[page="" 66437]]="" msha's="" proposal="" would="" relieve="" the="" mine="" operator="" from="" specifying="" the="" audiological="" test="" procedure="" and="" criteria.="" the="" mine="" operator="" would="" rely="" on="" the="" professional="" judgement="" of="" the="" physician="" or="" audiologist="" to="" select="" the="" appropriate="" tests="" and="" criteria.="" certification="" would="" not="" be="" accepted="" from="" a="" qualified="" technician;="" pursuant="" to="" the="" proposed="" provisions="" in="" sec.="" 62.140,="" qualified="" technicians="" are="" to="" perform="" their="" work="" under="" the="" supervision="" of="" a="" physician="" or="" audiologist.="" msha="" believes="" that="" it="" is="" necessary="" for="" the="" physician="" or="" audiologist="" to="" certify="" that="" the="" audiological="" tests="" were="" conducted="" in="" accordance="" with="" a="" scientifically="" validated="" procedure.="" in="" most="" cases,="" the="" mine="" operator="" does="" not="" have="" sufficient="" medical="" knowledge="" to="" determine="" if="" the="" tests="" were="" properly="" conducted="" and="" must="" rely="" on="" the="" judgement="" of="" a="" physician="" or="" audiologist.="" the="" certification="" will="" stand="" as="" evidence="" that="" the="" audiological="" tests="" were="" conducted="" in="" accordance="" with="" the="" requirements="" for="" a="" scientifically="" validated="" procedure.="" audiometric="" test="" recordkeeping="" and="" retention="" section="" 62.150(c)="" of="" msha's="" proposal="" would="" require="" that="" mine="" operators="" maintain="" a="" record="" of="" each="" required="" audiometric="" test.="" this="" record="" would="" contain--="" (1)="" the="" name="" and="" job="" classification="" of="" the="" miner="" tested="" (2)="" a="" copy="" of="" the="" miner's="" audiogram(s)="" (original="" baseline,="" annual,="" and="" supplemental="" baseline);="" (3)="" certification(s)="" that="" the="" tests="" were="" conducted="" using="" scientifically="" validated="" procedures;="" (4)="" any="" exposure="" determination="" for="" the="" miner;="" and="" (5)="" the="" results="" of="" any="" follow-up="" examination(s).="" this="" information="" would="" not="" have="" to="" be="" written="" on="" the="" actual="" audiogram="" as="" long="" as="" it="" was="" kept="" with="" the="" audiogram.="" the="" audiometric="" test="" records="" would="" be="" required="" to="" be="" maintained="" at="" the="" mine="" site="" for="" the="" duration="" of="" the="" affected="" miner's="" employment="" plus="" at="" least="" six="" months.="" although="" not="" defined="" in="" this="" proposal,="" by="" the="" term="" ``duration="" of="" employment''="" msha="" means="" the="" period="" of="" time="" between="" the="" date="" of="" a="" miner's="" initial="" hiring="" and="" the="" date="" on="" which="" the="" miner="" is="" released,="" quits,="" retires,="" or="" dies.="" there="" must="" be="" a="" lapse="" of="" at="" least="" six="" months="" beyond="" formal="" termination="" of="" employment="" before="" a="" mine="" operator="" could="" destroy="" the="" audiometric="" test="" records.="" moreover,="" it="" is="" msha's="" intent="" that="" a="" layoff,="" strike,="" lockout,="" furlough,="" period="" of="" leave="" (both="" paid="" and="" unpaid),="" or="" other="" temporary="" break="" in="" service="" would="" not="" be="" considered="" as="" a="" formal="" termination="" of="" employment,="" even="" if="" it="" exceeds="" six="" months.="" msha's="" existing="" standards="" have="" no="" requirements="" in="" this="" area.="" osha's="" noise="" standard="" requires="" that="" employers="" maintain="" a="" record="" of="" the="" audiometric="" test="" results="" and="" maintain="" these="" records="" for="" the="" duration="" of="" employment.="" since="" the="" publication="" of="" the="" noise="" standard,="" osha="" promulgated="" 29="" cfr="" 1910.20="" access="" to="" employee="" medical="" records.="" this="" standard="" applies="" to="" all="" medical="" records="" required="" to="" be="" kept="" pursuant="" to="" osha="" standards--="" noise="" records="" are="" treated="" in="" the="" same="" way="" as="" carcinogen="" records.="" under="" 1910.20,="" osha="" requires="" that="" medical="" records="" for="" each="" employee="" be="" maintained="" for="" at="" least="" the="" duration="" of="" employment="" plus="" (30)="" years,="" with="" the="" exception="" of="" employees="" who="" have="" worked="" for="" less="" than="" (1)="" year="" for="" the="" employer.="" the="" medical="" records="" for="" these="" employees="" need="" not="" be="" retained="" beyond="" the="" term="" of="" employment="" if="" they="" are="" provided="" to="" the="" employee="" upon="" termination.="" further="" this="" standard="" requires="" that="" exposure="" records="" be="" maintained="" for="" at="" least="" 30="" years.="" additionally,="" osha's="" noise="" standard="" requires="" that="" the="" audiometric="" test="" record="" include--="" (1)="" name="" and="" job="" classification="" of="" the="" employees;="" (2)="" date="" of="" the="" audiogram;="" (3)="" examiner's="" name;="" (4)="" date="" of="" the="" last="" acoustic="" or="" exhaustive="" calibration="" of="" the="" audiometer;="" and="" (5)="" employee's="" most="" recent="" noise="" exposure="" assessment.="" additionally,="" employers="" are="" required="" to="" maintain="" an="" accurate="" record="" of="" background="" sound="" pressure="" levels="" in="" audiometric="" test="" rooms.="" osha's="" noise="" standard="" has="" no="" requirement="" to="" maintain="" these="" records="" at="" the="" employer's="" work="" site.="" msha="" received="" a="" number="" of="" comments="" specifically="" addressing="" time="" frames="" for="" maintaining="" audiometric="" test="" records.="" one="" commenter="" recommended="" that="" they="" be="" maintained="" for="" 30="" years.="" two="" commenters="" recommended="" that="" such="" records="" be="" retained="" for="" the="" duration="" of="" the="" miner's="" employment="" plus="" 30="" years.="" most="" of="" the="" commenters="" on="" this="" issue="" recommended="" that="" msha="" require="" that="" audiometric="" test="" results="" be="" kept="" for="" the="" duration="" of="" employment.="" msha="" also="" reviewed="" the="" audiometric="" test="" recordkeeping="" and="" retention="" requirements="" from="" the="" u.s.="" armed="" forces="" and="" various="" other="" countries.="" generally,="" the="" audiometric="" test="" record="" is="" to="" be="" maintained="" for="" at="" least="" the="" duration="" of="" employment.="" msha="" considered="" allowing="" mine="" operators="" to="" keep="" the="" audiometric="" test="" record="" at="" a="" location="" other="" than="" the="" mine="" site.="" the="" agency="" concluded,="" however,="" that="" this="" alternative="" was="" impractical="" because="" it="" could="" delay="" msha's="" access="" to="" such="" records.="" furthermore,="" it="" would="" be="" burdensome="" for="" mine="" operators="" to="" copy="" and="" mail="" the="" records="" or="" send="" a="" fax="" of="" these="" records="" to="" the="" agency.="" msha="" believes="" that="" this="" record="" should="" be="" retained="" for="" at="" least="" six="" months="" beyond="" the="" duration="" of="" the="" miner's="" employment.="" the="" risk="" of="" harm="" stops="" with="" the="" cessation="" of="" employment;="" keeping="" the="" records="" an="" additional="" 6="" months="" would="" assure="" that="" a="" miner's="" audiometric="" test="" records="" are="" not="" destroyed="" and="" are="" available="" for="" use="" by="" the="" mine="" operator="" to="" conduct="" further="" evaluations="" should="" a="" miner="" return="" within="" that="" time="" period.="" in="" practice,="" msha="" believes="" that="" many="" mine="" operators="" will="" keep="" miner's="" audiograms="" long="" after="" the="" miner's="" employment="" ceases,="" for="" use="" if="" the="" miner="" should="" file="" a="" subsequent="" workers'="" compensation="" claim="" for="" hearing="" loss.="" in="" some="" states,="" the="" worker="" has="" many="" years="" following="" employment="" to="" file="" such="" a="" claim.="" the="" proposed="" items="" included="" in="" the="" audiometric="" test="" record="" would="" provide="" essential="" information="" to="" msha="" and="" to="" the="" health="" professional="" for="" evaluating="" a="" miner's="" audiogram.="" the="" information="" is="" also="" necessary="" for="" identifying="" the="" audiograms,="" evaluating="" whether="" the="" audiometric="" tests="" have="" been="" conducted="" properly,="" and="" for="" determining="" whether="" the="" results="" are="" valid.="" further,="" the="" information="" is="" critical="" for="" the="" evaluator="" in="" determining="" whether="" an="" identified="" hearing="" loss="" was="" not="" work="" related="" or="" aggravated="" by="" occupational="" noise="" exposure.="" section="" 62.160="" evaluation="" of="" audiograms="" msha's="" proposal="" would="" require="" that="" the="" mine="" operator="" inform="" the="" person="" evaluating="" the="" audiogram="" of="" the="" requirements="" of="" this="" part="" and="" provide="" them="" with="" copies="" of="" the="" miner's="" audiometric="" test="" records.="" the="" mine="" operator="" would="" be="" responsible="" for="" having="" a="" physician,="" audiologist,="" or="" qualified="" technician="" determine="" if="" an="" audiogram="" is="" valid="" and="" if="" a="" standard="" threshold="" shift="" (sts)="" or="" reportable="" hearing="" loss="" has="" occurred--in="" which="" case="" certain="" actions="" are="" required="" pursuant="" to="" sec.="" 62.180="" and="" sec.="" 62.190.="" time="" frames="" and="" privacy="" protection="" are="" part="" of="" the="" proposal,="" as="" is="" a="" requirement="" for="" a="" prompt="" retest="" if="" an="" audiogram="" is="" invalid.="" sts="" is="" defined="" in="" this="" proposal,="" as="" in="" osha's="" standard,="" as="" a="" change="" in="" a="" worker's="" hearing="" acuity="" for="" the="" worse,="" [[page="" 66438]]="" relative="" to="" that="" worker's="" baseline="" audiogram,="" of="" an="" average="" of="" 10="" db="" or="" more="" at="" 2000,="" 3000,="" and="" 4000="" hz="" in="" either="" ear.="" if="" the="" sts="" is="" determined="" to="" be="" permanent,="" a="" supplemental="" baseline="" is="" established="" pursuant="" to="" sec.="" 62.140="" and="" this="" becomes="" the="" baseline="" for="" determining="" any="" future="" sts.="" this="" definition="" is="" sufficiently="" restrictive="" to="" locate="" meaningful="" shifts="" in="" hearing,="" yet="" not="" so="" stringent="" as="" to="" create="" unnecessary="" follow-up="" procedures;="" the="" averaging="" of="" hearing="" levels="" at="" adjacent="" frequencies="" will="" reduce="" the="" effect="" of="" testing="" errors="" at="" single="" frequencies.="" the="" proposal="" would="" permit="" but="" not="" require="" mine="" operators="" to="" adjust="" audiometric="" test="" results="" by="" applying="" a="" correction="" for="" presbycusis="" before="" determining="" whether="" an="" sts="" or="" reportable="" hearing="" loss="" has="" occurred,="" and="" it="" includes="" tables="" for="" this="" purpose.="" presbycusis="" is="" the="" progressive="" loss="" of="" hearing="" acuity="" associated="" with="" the="" aging="" process.="" the="" proposed="" adjustment="" for="" presbycusis="" is="" optional;="" however,="" if="" a="" mine="" operator="" uses="" this="" approach,="" it="" must="" be="" applied="" uniformly="" to="" both="" the="" baseline="" and="" annual="" audiograms="" in="" accordance="" with="" the="" procedures="" and="" values="" listed="" in="" the="" proposed="" standard.="" although="" this="" is="" the="" position="" taken="" in="" the="" proposal,="" msha="" notes="" that="" the="" latest="" niosh="" advice="" on="" this="" topic="" has="" advised="" against="" the="" use="" of="" presbycusis="" correction="" factors.="" moreover,="" the="" agency="" is="" concerned="" about="" locking-in="" specific="" presbycusis="" adjustment="" tables.="" msha,="" therefore,="" requests="" additional="" comments="" on="" whether="" to="" use="" presbycusis="" corrections="" for="" audiograms="" and,="" if="" so,="" how="" to="" provide="" for="" such="" adjustment="" in="" a="" regulatory="" context.="" msha's="" existing="" noise="" standards="" do="" not="" address="" the="" evaluation="" of="" audiograms.="" msha's="" proposed="" requirements="" would="" be="" similar="" to="" those="" in="" osha's="" noise="" standard;="" the="" few="" differences="" are="" noted="" below.="" information="" provided="" to="" reviewer="" section="" 62.160(a)(1)="" of="" msha's="" proposal="" would="" require="" that="" the="" mine="" operator="" inform="" the="" person="" evaluating="" the="" audiogram="" of="" the="" requirements="" of="" this="" part="" and="" provide="" the="" evaluator="" with="" copies="" of="" the="" miner's="" audiometric="" test="" records.="" osha="" requires="" employers="" to="" provide="" the="" persons="" evaluating="" audiograms="" with="" a="" copy="" of="" the="" requirements="" of="" its="" standard,="" copies="" of="" the="" employee's="" baseline="" and="" most="" recent="" audiometric="" test="" records,="" background="" sound="" pressure="" levels="" in="" the="" audiometric="" test="" room,="" and="" a="" record="" of="" audiometer="" calibration.="" in="" its="" anprm,="" msha="" did="" not="" address="" what="" information="" the="" mine="" operator="" should="" provide="" to="" the="" person="" evaluating="" audiograms.="" the="" commenters,="" therefore,="" did="" not="" address="" this="" issue="" specifically.="" in="" discussing="" related="" topics,="" some="" commenters="" recommended="" that="" msha="" adopt="" osha's="" requirements="" on="" this="" issue.="" recently,="" research="" has="" implicated="" exposure="" to="" chemicals="" as="" aggravating="" hearing="" loss,="" fetcher="" (1995),="" morata="" (1989,="" 1993,="" 1995).="" msha="" requests="" comments="" as="" to="" how="" to="" address="" various="" aspects="" of="" this="" possible="" relationship.="" for="" example,="" could="" exposure="" to="" chemicals="" cause="" an="" invalid="" audiogram?="" what="" information="" should="" reviewers="" have="" about="" chemical="" exposure?="" any="" research="" results="" on="" this="" topic="" would="" be="" welcome.="" msha="" believes="" that="" providing="" certain="" information="" is="" necessary="" for="" physicians="" and="" audiologists="" to="" evaluate="" the="" accuracy="" and="" validity="" of="" miners'="" audiograms.="" for="" example,="" the="" evaluator="" would="" need="" to="" know="" the="" procedure="" for="" determining="" an="" sts,="" the="" criteria="" for="" retest="" or="" medical="" follow-up,="" presbycusis="" correction="" procedures,="" and="" recordkeeping="" requirements.="" review="" of="" audiogram.="" under="" sec.="" 62.160(a)(2)="" of="" this="" proposal,="" the="" mine="" operator="" would="" be="" responsible="" for="" having="" a="" physician,="" audiologist,="" or="" qualified="" technician="" determine="" if="" an="" audiogram="" is="" valid="" and="" if="" an="" sts="" or="" reportable="" hearing="" loss="" has="" occurred.="" msha's="" proposal="" is="" consistent="" with="" the="" present="" osha="" noise="" standard.="" of="" the="" many="" commenters="" on="" this="" specific="" issue,="" most="" believed="" that="" professional="" review="" was="" necessary.="" one="" of="" these="" said="" that="" ``msha="" should="" require="" an="" audiologist="" or="" physician="" to="" evaluate="" audiograms="" that="" show="" standard="" threshold="" shifts="" [sts]="" or="" other="" unusual="" changes''.="" a="" few="" commenters="" felt="" that="" professional="" review="" was="" unnecessary.="" these="" commenters="" indicated="" that="" the="" person="" conducting="" the="" audiogram="" could="" inform="" the="" employee="" of="" the="" results,="" and="" explain="" the="" significance="" of="" these="" results,="" so="" that="" the="" employee="" could="" make="" any="" decisions="" regarding="" further="" testing="" or="" evaluation.="" the="" u.s.="" armed="" services="" and="" the="" international="" community="" vary="" on="" the="" medical="" expertise="" required="" to="" review="" audiograms.="" msha="" believes="" that="" audiograms="" need="" to="" be="" reviewed="" for="" validity;="" as="" noted="" below,="" if="" audiograms="" are="" not="" valid,="" the="" proposal="" would="" require="" a="" retest.="" examples="" of="" questionable="" audiograms="" are="" audiograms="" that="" show:="" large="" unilateral="" differences="" in="" hearing="" thresholds="" between="" the="" two="" ears;="" unusual="" frequency="" patterns="" that="" are="" not="" typical="" of="" nihl;="" thresholds="" that="" are="" not="" repeatable;="" or="" an="" unusually="" large="" hearing="" loss="" over="" a="" yearly="" period.="" msha="" maintains="" that="" the="" review="" of="" audiograms="" is="" an="" integral="" part="" of="" an="" audiometric="" testing="" program.="" qualifications="" for="" audiogram="" reviewers="" under="" sec.="" 62.160(a)(2)="" of="" this="" proposal,="" a="" mine="" operator="" would="" be="" required="" to="" have="" a="" physician,="" audiologist="" or="" a="" qualified="" technician="" who="" would="" be="" under="" the="" supervision="" of="" a="" physician="" or="" audiologist="" evaluate="" audiograms="" to="" determine="" their="" validity="" and="" whether="" an="" sts="" or="" reportable="" hearing="" loss="" has="" occurred.="" the="" qualifications="" of="" these="" individuals="" to="" conduct="" this="" evaluation="" are="" discussed="" under="" sec.="" 62.140="" qualifications="" of="" personnel="" along="" with="" the="" comments="" received="" on="" this="" issue.="" standard="" threshold="" shift="" (sts)="" this="" proposal="" would="" require="" the="" evaluator="" to="" determine="" whether="" a="" miner="" has="" incurred="" an="" sts="" in="" his/her="" hearing.="" sts="" is="" defined="" in="" this="" proposal="" as="" a="" change="" in="" a="" worker's="" hearing="" threshold="" relative="" to="" that="" worker's="" baseline="" audiogram="" of="" an="" average="" of="" 10="" db="" or="" more="" at="" 2000,="" 3000,="" and="" 4000="" hz="" in="" either="" ear.="" this="" requires="" that="" hearing="" loss="" be="" calculated="" by="" subtracting="" the="" current="" hearing="" levels="" from="" those="" on="" the="" baseline="" audiogram="" at="" 2000,="" 3000,="" and="" 4000="" hz;="" when="" the="" hearing="" losses="" at="" each="" frequency="" are="" averaged="" (added="" up="" and="" divided="" by="" three);="" if="" the="" average="" loss="" in="" either="" ear="" has="" reached="" 10="" db,="" it="" constitutes="" an="" sts.="" if="" the="" sts="" is="" determined="" to="" be="" permanent,="" a="" supplemental="" baseline="" is="" established="" pursuant="" to="" sec.="" 62.140="" and="" this="" becomes="" the="" baseline="" for="" determining="" any="" future="" sts.="" the="" definitions="" of="" ``baseline="" audiogram'',="" ``supplemental="" baseline="" audiogram'',="" and="" ``standard="" threshold="" shift''="" are="" discussed="" in="" detail="" in="" connection="" with="" proposed="" sec.="" 62.110.="" osha="" defines="" an="" sts="" in="" essentially="" the="" same="" way,="" requiring="" that="" employees'="" annual="" audiograms="" be="" compared="" to="" their="" baseline="" audiogram="" to="" determine="" if="" the="" annual="" audiogram="" is="" valid="" and="" if="" an="" sts="" has="" developed.="" of="" the="" numerous="" comments="" addressing="" the="" issue="" of="" sts="" in="" response="" to="" msha's="" anprm,="" many="" endorsed="" osha's="" definition="" of="" sts.="" one="" commenter="" stated="" that:="" the="" standard="" threshold="" shift="" (sts)="" concept="" is="" the="" basic="" foundation="" of="" a="" hearing="" conservation="" program="" and="" is="" the="" best="" indicator="" of="" early="" noise-induced="" hearing="" loss="" [nihl].="" it="" enables="" those="" conducting="" the="" audiometric="" examinations="" to="" have="" the="" needed="" ``red="" flag''="" to="" indicate="" when="" additional="" testing="" or="" evaluation="" is="" needed.="" it="" also="" enables="" the="" effectiveness="" of="" the="" employer's="" hearing="" conservation="" program="" to="" be="" evaluated="" and="" monitored.="" the="" criteria="" must="" be="" sensitive="" enough="" to="" identify="" meaningful="" changes="" in="" hearing="" but="" must="" not="" be="" so="" sensitive="" as="" to="" [[page="" 66439]]="" pick="" up="" spurious="" shifts="" or="" ``false-positives.''="" *="" *="" *="" identifying="" a="" standard="" threshold="" shift="" therefore="" means="" that="" the="" shift="" value="" must="" be="" outside="" the="" range="" of="" audiometric="" error=""> 5 dB) and 
    serious enough to warrant prompt attention.* * * The averaging of 
    shifts over adjacent frequencies minimizes normal test error, and 
    random errors will tend to cancel each other out. * * *
        In considering the frequencies to be used, it is noted that 4000 
    Hz is generally considered to be affected by noise the earliest and 
    most severely. The 2000 and 3000 Hz frequencies are very important 
    in understanding speech and should also be included in the 
    definition of STS.
        For the above-mentioned reasons, as well as simplifying the 
    process in facilities which have operations under both MSHA and OSHA 
    jurisdiction, we recommend MSHA adopt an average shift of 10 dB or 
    more at 2000, 3000, and 4000 Hz, relative to the baseline audiogram. 
    * * *
    
        Of those commenters who did not endorse OSHA's STS criteria, one 
    stated that OSHA's STS definition was ``* * * not stringent enough and 
    the worker hearing loss has progressed too far with this shift to be a 
    reliable preventive measure.'' Another stated--
    
        * * * the suggested criteria [OSHA's STS definition] provides no 
    benefit but additional testing, specialist costs, reporting, 
    administrative costs, and potential MSHA punitive fines. * * *
        The STS concept is misguided. A significant percentage * * * of 
    people will have changes take place in their hearing which would 
    qualify as an STS without any exposure to occupational noise.
    
        Royster (1992) proposes a definition of STS that is different from 
    OSHA's. In her definition, 15 dB of hearing loss (relative to the 
    baseline) must occur at any audiometric test frequency from 500 to 6000 
    Hz on two sequential audiograms, before the STS is established. The 15 
    dB of hearing loss which occurs on two sequential audiograms identifies 
    the largest number of true positives (permanent threshold shifts) and 
    the least number of false positives (temporary threshold shifts 
    mistakenly identified as permanent threshold shifts).
        NIOSH (1995) recommends that the criteria for an STS be a 15 dB 
    decrease in hearing acuity at any one of the audiometric test 
    frequencies from 500 to 6000 Hz on two sequential audiograms. The shift 
    in hearing acuity must be in the same ear. The second audiogram would 
    be administered as soon as reasonable. NIOSH believes this criteria is 
    sufficiently stringent to detect beginning hearing loss, yet won't 
    include workers whose hearing acuity is simply showing normal 
    variability. If the 15 dB change is found, an immediate retest should 
    be conducted and followed by a confirmation test within 30 days. The 
    confirmation test should be preceded by 14 hours of quiet.
        This draft criteria for STS differs from the criteria recommended 
    by NIOSH in their 1972 criteria document. NIOSH's previous criteria 
    defined STS as a change of 10 dB or more at 500, 1000, 2000 or 3000 Hz; 
    or 15 dB or more at 4000 or 6000 Hz.
        There are some instances where large shifts in hearing level occur 
    at higher test frequencies (4000 and 6000 Hz) with little or no change 
    in hearing level at the middle frequencies. While large shifts are 
    uncommon, they may occur in noise-sensitive individuals, especially in 
    the early stages of NIHL. Correctly identifying significant threshold 
    shifts is particularly important for workers who have already begun to 
    lose their hearing. The proposed definition of STS would identify 
    individuals suffering shifts as large as 30 dB at 4000 Hz with no 
    shifts at the lower frequencies (30 plus 0 plus 0 divided by 3 equals 
    10, an STS). This permits the early identification of individuals at 
    risk, so that corrective measures could be taken.
        MSHA's proposed definition of STS is sufficiently restrictive to 
    locate meaningful shifts in hearing, yet not so stringent as to create 
    unnecessary follow-up procedures. The averaging of hearing levels at 
    adjacent frequencies will reduce the effect of testing errors at single 
    frequencies. The occurrence of an STS is serious enough to warrant 
    prompt attention because it may be a precursor to material impairment 
    of hearing. It is important to note that MSHA does not equate STS with 
    material impairment caused by NIHL.
        MSHA believes, after considering the relevant factors and reviewing 
    current U.S. military and international standards, that the proposed 
    definition of STS is the most appropriate and consistent with the 
    purposes of its hearing conservation standard. The proposed definition 
    of STS--
        (1) is adequately supported in OSHA's record for its Hearing 
    Conservation Amendment;
        (2) is the criteria recommended or accepted by most commenters to 
    MSHA's ANPRM;
        (3) results in a high degree of accuracy in identifying workers for 
    follow-up;
        (4) concentrates on those frequencies that are the earliest or the 
    most severely affected by noise; and
        (5) is a recognized and relatively simple approach.
        Because NIOSH revised its recommendation for the criteria of an 
    STS, MSHA requests comments on NIOSH's new criteria. Furthermore, any 
    data on the advisability of using either the MSHA proposed criteria of 
    STS or NIOSH's criteria of STS would be welcomed.
    Reportable Hearing Loss
        The proposal would require the evaluator to determine if there has 
    been a ``reportable hearing loss''. See the discussion of ``Reporting 
    noise-induced hearing loss (NIHL)'' under Sec. 62.190 Notification of 
    results.
    Instruction to Medical Professional
        Section 62.160(a)(3) of the proposal would require the mine 
    operator to instruct the physician or audiologist not to reveal to the 
    mine operator any specific findings or diagnoses unrelated to the 
    miner's exposure to noise or the wearing of hearing protectors without 
    the written consent of the miner. Currently, neither MSHA nor OSHA have 
    such a provision in their noise standards; OSHA does have such 
    provisions in air quality standards like benzene and lead.
        The topic of instructions to medical professionals was not raised 
    in the ANPRM. Therefore, no comments on this issue were received.
        MSHA believes that this requirement is necessary to safeguard the 
    privacy of individuals. The mine operator does not need to be informed 
    of medical conditions unrelated to occupational noise exposure. MSHA's 
    rationale is that if the mine operator had confidential medical 
    information, the mine operator could use it to justify an adverse 
    action against the miner.
    30-Day Requirement
        According to Sec. 62.160(a)(4) of MSHA's proposal, the mine 
    operator would have 30 days to obtain the audiometric results and the 
    interpretation of the results from the person evaluating the audiogram. 
    OSHA does not specify a time period for evaluating audiograms.
        MSHA's ANPRM did not address the issue of time frame for evaluating 
    audiograms. A few commenters, however, expressed concern with the 
    length of time that some service providers take to report results to 
    the employer. One stated that:
    
        Service providers have taken undue advantage of a perceived 
    `grace period' in the OSHA Hearing Conservation Amendment to inform 
    employees of a shift in hearing. * * * the lag time may total six to 
    eight weeks. This is a disservice to the employee, and is certainly 
    preventable.
        Notification of STS, including the optional retest of STS-
    affected employees, should be completed within a 30-day period 
    following testing. OSHA's time limit of 21 days following 
    notification to the employer creates a loophole which makes the 
    employee wait all too long for feedback regarding STS.
    
    
    [[Page 66440]]
    
    
        The other commenter stated that:
    
        In reality, from the time the hearing test is sent to an 
    audiologist or physician to review, it is reviewed, recommendations 
    made, it is returned to the plant personnel and the plant has 21 
    days to notify the employee, the total process often stretches into 
    a 45-60 day time frame.
    
        MSHA believes that a 30-day limit to evaluate audiograms is 
    reasonable and necessary to prevent undue delays in the evaluation of 
    the audiogram and notification to the miner of the results. Under 
    proposed Sec. 62.190, a miner would have to be notified within 10 
    working days of audiogram results obtained by the mine operator, as 
    discussed in connection with that section; accordingly, the net result 
    of these provisions is a maximum delay of approximately 44 days from 
    the date of audiometric testing to the notification of the miner. If a 
    retest was conducted, which, as discussed below must be done within 30 
    days of receiving a determination that the original test was invalid, 
    this delay in notification could be as long as 104 days. If the miner's 
    employment ceases during this delay period, the mine operator would be 
    required to provide the miner with a copy of the audiometric test 
    records as required by Sec. 62.200(c), including the results of all 
    testing, as soon as the record is complete. MSHA welcomes comments on 
    this issue.
    Audiometric Retest
        Section 62.160(b)(1) of the proposal would require a mine operator 
    to conduct a retest, if the audiogram was judged to be invalid, within 
    30 calendar days of receiving this information--provided, however, that 
    the 30-day time frame is stayed until any medical pathology resulting 
    in the invalid audiogram has improved to the point that a valid 
    audiogram may be obtained. In addition, Sec. 62.160(b)(2) of the 
    proposal would allow a mine operator to obtain one retest within 30 
    days after an STS or reportable hearing loss is found, and to 
    substitute the retest audiogram for the annual audiogram. The latter 
    retest is not mandatory.
        OSHA also permits a retest within 30 days to confirm an STS, but 
    does not specifically require a retest if the audiogram is judged to be 
    invalid.
        Many commenters supported OSHA's retest provision as written, while 
    others supported it with qualifications. One commenter believed that a 
    60-day period was appropriate. Another believed that a 30-day 
    limitation to both retest and notify was appropriate because:
    
        Service providers have taken undue advantage of a perceived 
    grace period in the OSHA Hearing Conservation Amendment to inform 
    employees of a shift in hearing. By the time audiometric tests are 
    administered, entered into a computer, returned to an employer, and 
    then finally returned to the employee, the lag time may total six to 
    eight weeks. This is a disservice to the employee, and is certainly 
    preventable.
    
        Other commenters stated different views. One commenter stated that:
    
        * * * most programs involve the use of testing vans that cannot 
    easily make a return trip in 30 days because of scheduling limits. 
    It would also be extremely expensive to make a return trip to 
    confirm a single STS. If an employee is found to have a significant 
    hearing loss, he should be required to wear hearing protectors in 
    all noise environments of 85 dBA or greater. If the next scheduled 
    audiogram also shows the hearing loss, then the loss should be 
    considered confirmed.
    
        Another commenter stated that:
    
        * * * an employee with a change in hearing could be immediately 
    counseled, refitted [i.e., hearing protectors], educated, notified 
    and return to his job. This would be more cost-effective than 
    bringing him back prior to the shift to get a hearing test showing 
    there is no STS.
    
        MSHA believes, after considering comments and reviewing U.S. armed 
    forces and international standards, that the retest provisions are 
    necessary to assure that valid audiograms are provided in a timely 
    fashion. The retest should be conducted within a reasonable time, and 
    30 days is believed to be adequate, with the caveat that this time 
    frame does not begin to run until any medical pathology causing a 
    validity problem has improved to the point that a valid audiogram can 
    be obtained. MSHA recognizes that in such cases it will not be possible 
    to wait for a mobile van; but MSHA believes that in the limited number 
    of cases where a retest is required, it is appropriate and necessary to 
    send the miner to the nearest available facility for such a test.
        The provision to obtain an optional retest if an STS is detected is 
    desirable. This would permit the mine operator to substantiate that an 
    STS had occurred, thus confirming permanent hearing loss. By detecting 
    only permanent hearing loss, the mine operator would have better 
    information on which to base administrative, technical, and financial 
    decisions relative to retraining the miner, permitting the miner to 
    select a different or additional hearing protector, and reviewing the 
    effectiveness of the noise controls.
    Use of Age Correction (Presbycusis Factors)
        Section 62.160(c) of the proposal would permit mine operators to 
    adjust audiometric test results by applying a correction for 
    presbycusis before determining whether an STS or reportable hearing 
    loss has occurred. Presbycusis is the progressive loss of hearing 
    acuity associated with the aging process. This adjustment for 
    presbycusis is optional; however, if it is used, it must be applied 
    uniformly to both the baseline and annual audiograms in accordance with 
    the procedures and values listed in Sec. 62.160(c) (1) through (4).
        OSHA's noise standard also permits the use of presbycusis 
    correction factors. MSHA's proposal would be essentially the same as 
    OSHA's Appendix F: Calculations and Application of Age Corrections to 
    Audiograms. Both MSHA's proposal and OSHA's Appendix F adopt the 
    procedures and age correction tables used by NIOSH in its criteria 
    document (1972).
        Commenters to OSHA's Hearing Conservation Amendment (48 FR 9763) 
    suggested that the use of such presbycusis factors also would account 
    for those cases of NIHL that arise from causes other than occupational 
    noise exposure. In the preamble to its Hearing Conservation Amendment 
    (48 FR 9763), OSHA states that:
    
    * * * these correction factors will aid in distinguishing between 
    occupationally induced and age-induced hearing loss. This is 
    particularly important because the pattern of hearing loss due to 
    aging closely resembles that of noise-induced hearing loss [NIHL]. * 
    * * Therefore, although * * * the use of a correction factor may 
    complicate calculation procedures and cause some errors, * * * 
    professional supervision of the hearing conservation program will 
    ensure that audiometric technicians understand how to use the age 
    correction chart * * *
    
        Most commenters who addressed this issue in MSHA's ANPRM, contend 
    that the use of presbycusis correction factors is appropriate. Many of 
    these commenters supported MSHA's use of the same criteria as in OSHA's 
    Appendix F. Other commenters recommended age corrections different than 
    those used by OSHA. One commenter suggested that MSHA use the ISO 
    1999.2 (1989) standard. Another one suggested that, because the NIOSH 
    criteria is almost 20 years old, ``The criteria used should be the most 
    recent and [accepted] data.''
        Several commenters believed that applying presbycusis factors would 
    reduce unnecessary recordkeeping and follow-up procedures. One stated 
    that:
    
        Many audiometric computer programs used for processing data have 
    this correction calculation built in the software. To change to some 
    other criteria or to remove this factor will result in the 
    modification of numerous systems and a need to switch back and 
    forth,
    
    [[Page 66441]]
    
    depending on whether the operator is OSHA or MSHA regulated.
    
    Another of these suggested that MSHA require the use of such correction 
    factors, rather than allow their use to be optional, because such 
    optional use could result in discrepancies in results among audiometric 
    testing services.
        A few commenters suggested that it would be better not to adjust 
    audiometric test results for presbycusis. They maintained that the 
    place to claim credit for presbycusis is in determining workers' 
    compensation and not in the institution of an HCP. These commenters 
    believed that not everyone who ages loses their hearing to the same 
    degree, and that the use of presbycusis corrections might mask changes 
    for older adults who have previously had good hearing.
        Finally, one commenter recommended that MSHA seek medical advice 
    from national sources to determine what the medical community 
    recognizes as changes occurring from aging.
        In contrast to NIOSH's presentation of one set of presbycusis data, 
    the ISO Document ISO 1999:1990(E) (1990) gives a dual set of values for 
    the non-industrial noise exposed population. These data are offered in 
    two tables. One table represents a highly screened, otologically normal 
    population, i.e., persons in a normal state of health, free from all 
    signs and symptoms of ear disease and obstructing wax in the ear 
    canals, and having no history of undue exposure to noise. The second 
    table represents an unscreened population from an industrialized 
    country. The ISO states that the choice of using the screened or 
    unscreened data base depends on what question is to be answered. It 
    states:
    
        For example, if the amount of compensation that could be due to 
    a population of noise-exposed workers is to be estimated, and 
    otological irregularities and non-occupational noise exposure are 
    not considered in compensation cases, unscreened populations will 
    form the more appropriate data bases.
    
    The ISO further states, however, that its standard ``* * * is based on 
    statistical data and therefore shall not be used to predict or assess 
    the hearing impairment or hearing handicap of individual persons.'' The 
    ISO data would be more difficult to use than NIOSH data because its 
    interpretation would require a higher level of statistical and 
    mathematical expertise.
        NIOSH (1995) now recommends that audiograms not be corrected for 
    presbycusis. NIOSH believes that it is inappropriate to apply 
    presbycusis correction factors from a population to an individual. 
    Furthermore, there are no data to confirm that a 50 year old in 1995 
    will incur the same hearing loss due to aging that a 50 year old did in 
    1970. If the worker's audiogram is to be corrected for presbycusis, 
    then the hearing loss of a non-occupational noise exposed group with 
    the same demographic characteristics as the worker should be used. 
    However, these kinds of data are not complete nor are they readily 
    available.
        The following is an example of the use of presbycusis correction 
    factors as proposed in MSHA's noise standard--
        (a) Determine from Tables 62-3 or 62-4 the age correction values 
    for the miner by--
        (1) Finding the age at which the baseline audiogram (or 
    supplementary baseline audiogram if appropriate) was taken and 
    recording the corresponding values of age correction at 2000 Hz through 
    4000 Hz; and
        (2) Finding the age at which the most recent audiogram was taken 
    and recording the corresponding values of age correction at 2000 Hz 
    through 4000 Hz.
        (b) Subtract the value found in step (1) from the value found in 
    step (2). The differences calculated represent that portion of the 
    change in hearing that may be due to aging.
        (c) Subtract the value found in step (b) from the hearing threshold 
    level found in the annual audiogram to obtain the adjusted annual 
    audiogram hearing threshold level.
        (d) Subtract the hearing threshold in the baseline audiogram (or 
    supplemental baseline audiogram as appropriate) from the adjusted 
    annual audiogram hearing threshold level to obtain the age-corrected 
    threshold shift.
         Example: A miner is a 32-year-old male. The audiometric history in 
    decibels is shown below for his right ear. A threshold shift of 10 dB 
    at 2000 and 3000 Hz and 20 dB at 4000 Hz exists between the audiograms 
    taken at ages 27 and 32. A retest audiogram has confirmed this shift.
    
    ------------------------------------------------------------------------
                                                         Audiometric test   
                                                          frequency (Hz)    
                       Miner's age                   -----------------------
                                                       2000    3000    4000 
    ------------------------------------------------------------------------
     26.............................................       5       5      10
    *27.............................................       0       0       5
     28.............................................       0       0      10
     29.............................................       0       5      15
     30.............................................       5      10      20
     31.............................................      10      20      15
    +32.............................................      10      10     25 
    ------------------------------------------------------------------------
    An asterisk (*) has been used to identify the supplemental baseline     
      audiogram and a plus (+) the most recent audiogram. The annual        
      audiogram taken at age 27 becomes a supplemental baseline audiogram   
      (and is used in calculating hearing loss) because it shows a          
      significant improvement over the baseline audiogram taken at age 26.  
    
        Steps (a) and (b). Find the age correction values (in dB) at age 27 
    and age 32 in Table 62-3. The difference, shown below, represents the 
    amount of hearing loss that may be attributed to aging in the time 
    period between the baseline audiogram and the most recent audiogram.
    
    ------------------------------------------------------------------------
                                                          Frequency (Hz)    
                                                     -----------------------
                                                       2000    3000    4000 
    ------------------------------------------------------------------------
    Age 32..........................................       5       7      10
    Age 27..........................................       4       6       7
    Difference......................................       1       1       3
    ------------------------------------------------------------------------
    
        Step (c). Subtract the difference determined in step (b) from the 
    hearing levels in the most recent audiogram. In this example, the 
    adjusted hearing threshold levels are as follows:
    
    ------------------------------------------------------------------------
                                                          Frequency (Hz)    
                                                     -----------------------
                                                       2000    3000    4000 
    ------------------------------------------------------------------------
    Age 32..........................................      10      10      25
    Correction......................................       1       1       3
    Adjusted........................................       9       9      22
    ------------------------------------------------------------------------
    
        Step (d). Subtract the hearing threshold level in the baseline 
    audiogram from the adjusted annual audiogram hearing threshold to 
    obtain the age-corrected threshold shift.
    
    ------------------------------------------------------------------------
                                                          Frequency (Hz)    
                                                     -----------------------
                                                       2000    3000    4000 
    ------------------------------------------------------------------------
    Adjusted........................................       9       9      22
    Baseline........................................       0       0       5
    Shift...........................................       9       9      17
    ------------------------------------------------------------------------
    
        The average threshold shift at 2000, 3000, and 4000 Hz without age 
    correction is (10+10+20)/3=13.3 dB. The average age-corrected threshold 
    shift at 2000, 3000, and 4000 Hz is (9+9+17)/3=11.7 dB. This shift is 
    an STS because it exceeds 10 dB, but it is not, as yet, a reportable 
    hearing loss (25 dB). Intervention at this point should prevent further 
    loss and subsequent impairment.
        MSHA agrees that not all individuals are affected by presbycusis to 
    the same degree. Additionally, studies have
    
    [[Page 66442]]
    
    shown that individuals in environments free from noise exposure display 
    little evidence of presbycusis. MSHA is concerned that the use of 
    presbycusis corrections may allow some miners to incur excess work-
    related hearing loss. For example, some miners may not have off-the-job 
    noise exposure and may not have a decrement in their hearing due to 
    aging at the levels specified in the presbycusis correction table. 
    Nevertheless, MSHA maintains that at this time, allowing the adjustment 
    of audiometric test results for presbycusis is both reasonable and 
    appropriate. In industrial audiometry, this correction is often used to 
    determine occupational NIHL by adjusting the measured hearing level to 
    compensate for the normal loss of hearing due to aging. This is 
    particularly important because the pattern of hearing loss due to aging 
    resembles that of NIHL. The use of age corrections will help the mine 
    operator judge how well the HCP is working. Such adjustments are 
    consistent with current scientific practice, OSHA's standard, and the 
    recommendations of the majority of the commenters to MSHA's ANPRM.
        MSHA selected the NIOSH presbycusis data so that all mine operators 
    who correct audiograms for aging will be using the same data. Though 
    there may be slight variations at individual frequencies, the NIOSH 
    presbycusis values are similar to those of other well known presbycusis 
    data bases, such as the U.S. Public Health Service data, those used by 
    Robinson and Burns, and those of Passchier-Vermeer. The NIOSH data are 
    for a highly screened population which excluded individuals with any 
    significant noise exposure on-the-job, off-the-job, or during military 
    service. Using a single set of presbycusis values will standardize the 
    process of determining STS nationwide. If MSHA allowed mine operators 
    to select their own presbycusis values, there could be major 
    nonuniformity in determining STS's and reportable hearing losses. 
    Nevertheless, the Agency is concerned about locking-in particular 
    presbycusis adjustment tables, and requests additional comments on how 
    to provide for a presbycusis adjustment in a regulatory context.
        In conclusion, MSHA believes that, at this time, scientific data 
    and the consensus of commenters support allowing the use of the 
    presbycusis correction factors presented in Tables 62-3 and 62-4. 
    Although this is the position taken in the proposal, MSHA notes that 
    the latest NIOSH advice on this topic has advised against the use of 
    presbycusis correction factors. MSHA, therefore, requests additional 
    comments on whether to use presbycusis corrections for audiograms.
    
    Section 62.170  Follow-up Evaluation When Audiogram Invalid
    
        This section of the proposal provides that when a valid audiogram 
    cannot be obtained due to a suspected medical pathology of the ear, and 
    the physician or audiologist evaluating the audiogram believes that the 
    problem was caused or aggravated by the miner's exposure to noise or 
    the wearing of hearing protectors, a miner must be referred for a 
    clinical audiological or otological evaluation as appropriate at mine 
    operator expense.
        This section also provides that if the physician or audiologist 
    concludes that the suspected medical pathology of the ear which 
    prevents obtaining a valid audiogram is unrelated to the miner's 
    exposure to noise or the wearing of hearing protectors, the miner be 
    advised of the need for an otological evaluation; but in such cases, no 
    financial obligation would be imposed on mine operators.
        Finally, this section would require the mine operator to instruct 
    the physician or audiologist not to reveal to the mine operator any 
    specific findings or diagnoses unrelated to the miner's exposure to 
    noise or the wearing of hearing protectors without the written consent 
    of the miner.
        OSHA's noise standard has similar follow-up requirements, except 
    for the nondisclosure provision. MSHA's current noise standards have no 
    follow-up evaluation provisions.
        In response to MSHA's ANPRM, many commenters supported OSHA's or 
    similar requirements for referring employees to a physician for a 
    medical follow-up. A few commenters, however, stated that ``MSHA need 
    not include criteria for directing miners for further medical follow-up 
    nor require a physician, audiologist, or other qualified medical 
    personnel to evaluate the audiograms.''
        Another commenter stated the following regarding who should pay for 
    these follow-up evaluations:
    
        * * * I have a standard recommendation when working with 
    companies that they pay for all initial medical evaluations in order 
    to determine disposition. I think it is as important to them to have 
    documentation that an employee has a medical problem just as [when] 
    he has an occupational one.
    
        The decision as to which type of evaluation, clinical audiological 
    evaluation or otological, is appropriate will depend upon the 
    circumstances. Standards from the international community and the U.S. 
    Armed Forces vary to some degree regarding certain elements, such as 
    the extent of follow-up examinations. A clinical audiological 
    evaluation is generally more comprehensive, intensive, and accurate 
    than the routine audiometric testing conducted for HCP purposes. For 
    example, such testing may be warranted if an unusually large threshold 
    shift occurs in one year given relatively low noise exposures. An 
    otological evaluation, on the other hand, is a medical procedure 
    conducted by a physician specialist (e.g., otolaryngologist) to 
    identify a medical pathology of the ear. Audiometric testing can imply 
    the existence of such a medical pathology. For example, a hearing loss 
    in only one ear can indicate the existence of an acoustic neuroma (type 
    of tumor) at an early stage. Such discovery could be potentially life 
    saving. Another more common reason for an otological examination would 
    be for the removal of impacted ear wax (cerumen) which reduces hearing 
    acuity and can be aggravated by the use of insert-type hearing 
    protectors.
        Making the determinations under this section would not require a 
    diagnosis by a physician specialist confirming a medical pathology. The 
    proposal is intended to allow the audiologist or physician authorized 
    to review the audiograms to make a determination as to whether a 
    follow-up examination is appropriate--and who pays for it. Accordingly, 
    the word ``suspected'' precedes the words ``medical pathology'' in this 
    section.
        If the person evaluating the audiogram believes that the suspected 
    medical pathology is related to occupational noise exposure or to the 
    wearing of hearing protectors, the proposal would require the mine 
    operator to pay for the miner's follow-up medical evaluations. MSHA 
    believes that the mine operator has the primary responsibility for 
    work-related medical problems. On the other hand, if the person 
    evaluating the audiogram determines that the suspected medical 
    pathology is not related to the wearing of hearing protectors, then the 
    proposal would require the mine operator to instruct the medical 
    professional to inform the miner of the need for medical follow-up, but 
    would not require the mine operator to pay for it or to be informed of 
    the findings. In such cases, therefore, the follow-up otological 
    examination would be at the miner's expense. Although MSHA agrees that 
    taking action to keep miners healthy would be beneficial to the mine 
    operator, the Agency contends that it would be inappropriate to require 
    mine
    
    [[Page 66443]]
    
    operators to pay for non-work-related medical problems.
        MSHA also does not believe that it would be appropriate for mine 
    operators to be informed of medical findings that are unrelated to the 
    miner's occupational noise exposure or to the wearing of hearing 
    protectors. If a mine operator would want this information, the 
    proposal would permit the release of this information only upon the 
    written consent of the miner. MSHA has included this provision out of 
    concern for the privacy rights of the miner. A related provision is 
    considered in somewhat more detail in the discussion of proposed 
    Sec. 62.160.
    
    Section 62.180  Follow-Up Corrective Measures When STS Detected
    
        MSHA's proposal would require that, unless a physician or 
    audiologist determines that an STS is neither work-related nor 
    aggravated by occupational noise exposure, mine operators would have 30 
    calendar days after the finding of an STS to--
        (1) Retrain the miner in accordance with Sec. 62.130;
        (2) Provide the miner with the opportunity to select a hearing 
    protector, or a different hearing protector if the miner has previously 
    selected one, from the selection offered under Sec. 62.125; and
        (3) Review the effectiveness of any engineering and administrative 
    controls to identify and correct any deficiencies. In addition, 
    pursuant to proposed Sec. 62.120(b), an operator would be required to 
    ensure that a miner who has incurred an STS wears provided hearing 
    protection.
        A hearing loss of 10 dB from a miner's prior hearing level is of 
    enough significance to warrant intervention by a mine operator, unless 
    it is determined the loss is not work-related. If the controls in place 
    are effective--including the training--this loss should not be 
    occurring. It should be noted that the retraining required is to take 
    place within 30 days after the finding of the STS, and thus it is 
    unlikely mine operators can satisfy this requirement through their part 
    48 training programs.
        MSHA's proposal does not include a provision for transferring a 
    miner who incurs repeated STS's or a reportable hearing loss. A miner 
    transfer program would be complex to administer, and would probably not 
    be feasible in the metal and nonmetal sector. This sector consists 
    largely of smaller mines which may be unable to rotate workers to other 
    assignments on a long-term basis.
        Most commenters on this issue suggested that MSHA adopt OSHA's 
    requirements. One of these commenters, however, disagreed with OSHA's 
    allowance for discontinued use of hearing protectors when an STS was 
    found to be temporary. The remaining two commenters recommended that 
    the mine operator only be required to retrain the miner in the use and 
    fit of the hearing protector.
        OSHA's noise standard requires that the work-relatedness of an STS 
    be determined only by a physician. Employees, who have a work-related 
    STS and are not using hearing protectors, must be fitted with hearing 
    protectors, be trained in their use and care, and be required to use 
    them. Employees who have an STS and are using hearing protectors must 
    be refitted, be retrained, and be provided with hearing protectors 
    offering greater attenuation when necessary. OSHA does not stipulate a 
    time frame for conducting follow-up procedures.
        MSHA believes that audiologists have sufficient training and 
    medical expertise to determine the work-relatedness of an STS, and that 
    it would be needlessly restrictive to limit this determination to a 
    physician as in OSHA's standard.
        MSHA, however, like OSHA would not permit technicians to make this 
    determination. MSHA believes that while qualified to conduct and 
    evaluate audiograms under the supervision of a physician or 
    audiologist, technicians do not have the necessary training nor medical 
    expertise to determine if an STS is work related. MSHA has determined 
    that it is necessary to have a physician or audiologist determine the 
    possible work relatedness of any STS. For example, the physician may 
    determine that a miner's STS resulted from: a bad cold or sinus 
    condition; taking certain medication, such as heavy doses of aspirin; 
    or an acoustic neuroma (type of tumor). Careful diagnosis may, on the 
    other hand, reveal that the STS is work related and caused by improper 
    fit of the hearing protector.
        MSHA, after reviewing comments and related regulations, believes 
    that the proposed corrective measures are adequate and necessary to 
    prevent further deterioration of the miner's hearing acuity after an 
    STS has been determined. MSHA believes that the 30 day requirement for 
    retraining, selection of a hearing protector or different hearing 
    protector, and evaluation of noise controls is reasonable.
    Retraining
        If a miner has an STS, Sec. 62.180(a) of this proposal would 
    require that the miner be retrained in accordance with Sec. 62.130, and 
    a record kept of such training.
        The specific training elements contained in Sec. 62.130 are 
    discussed in the provisions of this preamble describing those 
    respective sections, including the required certification thereof. Such 
    retraining could be conducted in conjunction with the annual refresher 
    training, under 30 CFR part 48, but only if the latter is so approved 
    and scheduled to be completed within 30 days of the finding of an STS. 
    If the annual refresher training is not conducted within 30 days, the 
    retraining for miners with an STS would have to be conducted 
    separately. It would not be permissible to wait until the next annual 
    refresher training.
    Provide Opportunity To Select a Hearing Protector or Different Hearing 
    Protector
        In the mining industry, miners are typically exposed to high sound 
    levels and some of the miners may be more susceptible to hearing loss 
    from the noise exposures than others. Consequently, if a miner is 
    diagnosed with an STS, then he or she must be given the opportunity to 
    select a hearing protector or different hearing protector.
        Section 62.180(b) of this proposal directs the mine operator to 
    afford the miner the opportunity to select adequate hearing protection 
    from those offered by the mine operator under Sec. 62.125. While that 
    section of the proposal only requires the mine operator to offer one 
    type of ear plug and one type of ear muff, MSHA presumes that most mine 
    operators will offer a range of each. Pursuant to Sec. 62.120(b), the 
    operator is required to ensure that a miner with an STS wears the 
    hearing protector.
        The choice of hearing protectors from this selection will be based 
    on the miner's personal preference. The benefits of allowing the miner 
    to select his/her hearing protector are discussed under Sec. 62.125 
    Selection of hearing protector. MSHA believes that even though a miner 
    may select a protector with a noise reduction rating lower than that 
    which might be selected by a mine operator in such cases, factors such 
    as comfort are more critical in ensuring that the miner will fully 
    utilize this critical piece of personal protective equipment. Moreover, 
    as discussed in the section on Hearing protector effectiveness, MSHA 
    has concluded that there is no standardized objective method to 
    determine whether an additional or different hearing protector would 
    provide the miner with greater protection. MSHA requests further 
    comment on this issue.
    
    [[Page 66444]]
    
    Review Effectiveness of Controls
        Upon the finding of an STS, MSHA would require, under 
    Sec. 62.180(c) of the proposal, the mine operator to review the 
    effectiveness of any engineering and administrative controls. The mine 
    operator would need to correct any deficiencies. The implementation and 
    maintenance of either engineering or administrative controls or a 
    combination of such controls above the PEL is the primary method for 
    reducing a miner's noise exposure and, thus, reducing the risk of 
    hearing loss. OSHA's current noise regulation does not require a review 
    of the effectiveness of engineering and administrative controls when an 
    STS is found.
        The inadequacy of engineering or administrative controls or a 
    combination of such controls may well be the contributing factor in the 
    development of a miner's STS. Thus, the proposal would require the mine 
    operator to review the effectiveness of controls and update or modify 
    them, as necessary and feasible, to reduce the miner's noise exposure.
    Miner Transfer
        The Federal Mine Safety and Health Act of 1977 (30 U.S.C. 811) 
    requires health standards to include, as appropriate, provisions for 
    removing a miner from hazardous exposure where that miner may suffer 
    material impairment of health or functional capacity. MSHA has decided 
    not to include such a provision in its proposal.
        MSHA's current noise standards do not contain such a transfer 
    provision. Nor does the OSHA noise standard have such a requirement.
        In its ANPRM, MSHA requested comments regarding the need for a 
    transfer provision in the proposed rule for a miner with a diagnosed 
    occupational hearing loss. In response, many commenters stated that a 
    miner transfer provision is not appropriate. Some of the concerns 
    expressed by the commenters included: the negotiation of disability 
    accommodation sections in labor contracts; problems with rate retention 
    and seniority provisions in existing contracts; the contribution of 
    non-occupational noise exposure to the hearing loss; uncertainty as to 
    the etiology of the hearing loss; and the impracticality in small 
    operations. However, several commenters disagreed, indicating that the 
    transfer of a miner is appropriate when other efforts to halt the 
    progression of the hearing loss have failed. They added that the safety 
    of a miner with a hearing loss would be jeopardized, due to the 
    inability to hear warning signals and/or understand verbal instructions 
    in the noisy environment (a hazard to other miners as well).
        Several of the U.S. Armed Forces, and some other countries, allow 
    for removal or transfer of employees from noisy areas.
        Although MSHA would encourage mine operators to transfer miners who 
    have incurred a hearing impairment, MSHA believes that a miner transfer 
    provision would not be feasible, at the vast majority of small mining 
    operations, because of limited personnel and non-noise exposed 
    occupations. At larger mines transfer may be feasible; however, MSHA 
    believes that the obligation to utilize all feasible administrative (as 
    well as engineering controls) would reduce miner exposure time to 
    harmful noise in much the same way as a transfer provision but without 
    unwarranted complexity.
    
    Section 62.190  Notification of Results; Reporting Requirements
    
        This section of the proposal would require that miners be notified 
    of audiometric test findings, and that the Agency be notified of any 
    instances of ``reportable hearing loss.''
        The proposal would require the mine operator, within 10 working 
    days of receiving the results of an audiogram, or the results of a 
    follow-up evaluation pursuant to Sec. 62.170(a)--those follow-ups on 
    which the mine operator would receive results--to notify the miner in 
    writing of the results and interpretations, including any finding that 
    an STS or reportable hearing loss has occured. The notification would 
    include an explanation of the need and reasons for any further testing 
    or evaluation that may be required.
        MSHA believes that informing miners of the results of their 
    audiometric tests in a timely manner is critical to the success of an 
    HCP. Immediate feedback upon completion of the testing provides the 
    greatest benefit.
        The proposal would require mine operators to inform MSHA of any 
    reportable hearing loss, unless the physician or audiologist has 
    determined the loss is neither work-related nor aggravated by 
    occupational noise exposure. This essentially restates for noise the 
    requirements of 30 CFR part 50, but with an explicit definition of 
    reportable hearing loss for the first time. Having a uniform definition 
    will ease reporting burdens on mine operators while promoting the 
    development of an improved data base on hearing loss in the mining 
    community.
        The proposal would define a reportable hearing loss as a change in 
    hearing acuity for the worse relative to the miner's baseline audiogram 
    of an average of 25 dB or more at 2000, 3000, and 4000 Hz in either 
    ear. Should an annual audiogram actually indicate an improvement in 
    hearing at any time, this audiogram would, pursuant to Sec. 62.140, 
    become the baseline for purposes of determining whether a reportable 
    hearing loss has occurred. As noted herein, MSHA is seeking comment on 
    whether part 50 should collect information on harm on less dramatic 
    shifts in hearing acuity, and how reporting should be accomplished in 
    cases in which an operator lacks audiometric data.
    Notification of the Miner
        Section 62.190(a) of MSHA's proposal would require that within 10 
    working days of receiving the results of an audiogram or follow-up 
    evaluation, the mine operator shall notify the miner in writing of--
        (1) the results and interpretation of an audiometric test, 
    including any finding of an STS or a reportable hearing loss; and
        (2) if applicable, the need and reasons for any further testing or 
    evaluation.
        MSHA has no current requirements in this area. The proposed time 
    frame is consistent with the time frame for notification to the Agency, 
    under part 50, of cases of reportable hearing loss. MSHA's proposal 
    would differ from OSHA's standard in this regard and in several other 
    respects: the miner would be informed of the need and reason for 
    further medical evaluations, and the miner would be informed of the 
    finding of a reportable hearing loss. Moreover, OSHA's requirement does 
    not specify how long, following the annual audiogram, an employer can 
    take to make this determination.
        All commenters on this issue favored notifying the employee of the 
    results of audiometric testing and follow-up examinations. They 
    differed, however, as to the time to be allotted for such notification 
    and the requirements of such notification.
        Many commenters endorsed OSHA's requirements. One commenter agreed 
    that written notification be provided within 21 days, the same as OSHA, 
    but recommended that such notice be provided for all audiometric test 
    results. This commenter stated:
    
        It is our policy to notify all employees of the results of their 
    audiometric tests in writing. An appropriate time frame would be 21 
    days from the time the employee's facility is made aware of the 
    results. If the time frame for notification is 21 days from the time 
    of the actual test, many problems may arise. If a mobile testing 
    service is utilized, the results may not be sent in for analysis for 
    at least
    
    [[Page 66445]]
    
    a week. Our audiological staff reviews all of our audiograms in-
    house rather than relying on outside services for analysis. Some of 
    our testing services microfilm the tests or analyze them separately 
    which means that a delay of a few weeks may occur. The purpose 
    should be that the employee receive results in a timely enough 
    fashion so that they are meaningful.
    
        One commenter recommended that written notification be provided to 
    the miner within 30 days of determining a confirmed STS. Another 
    commenter recommended that miners be notified of an STS, including any 
    optional retest, within 30 days of the testing. This commenter stated 
    that:
    
        Service providers have taken undue advantage of a perceived 
    grace period in the OSHA Hearing Conservation Amendment to inform 
    employees of a shift in hearing. By the time audiometric tests are 
    administered, entered into a computer, returned to an employer, and 
    then finally returned to the employee, the lag time may total six to 
    eight weeks. This is a disservice to the employee, and is certainly 
    preventable.
        Notification of STS, including the optional retest of STS-
    affected employees, should be completed within a 30-day period 
    following testing. OSHA's time limit of 21 days following 
    notification to the employer creates a loophole which makes the 
    employee wait all too long for feedback regarding STS.
    
    Other commenters recommended notifying miners of the results of their 
    audiometric tests, but did not specify a time frame.
        The U.S. Armed Forces regulations, and standards of some members of 
    the international community, vary on the time frame for notification.
        The time frame in MSHA's proposal is shorter than the time frame 
    for notification in OSHA's standard, but is consistent with MSHA's 
    requirement that the Agency be notified of reportable hearing losses 
    within 10 working days. MSHA's proposal would also differ from OSHA's 
    standard in that the miner would be informed of the need and reason for 
    further medical evaluations; and the miner would be informed of the 
    finding of a reportable hearing loss. In addition, pursuant to 
    Sec. 62.170(b), MSHA's proposal would require the mine operator to 
    instruct the physician to notify the miner of the need for an 
    otological examination based upon a medical pathology of the ear that 
    is unrelated to the affected miner's noise exposure or the wearing of 
    hearing protectors. MSHA believes that miners have a right to know the 
    results of any medical tests conducted on them.
        MSHA believes that it is appropriate to require written 
    notification. Under proposed Sec. 62.200, the miner would in any event 
    have access to all required records under this part upon written 
    request. Providing the notices in writing would ensure there are no 
    misunderstandings on the part of miners as to the severity of the 
    problem.
        MSHA believes that informing miners of the results of their 
    audiometric tests in a timely manner is critical to the success of an 
    HCP. Immediate feedback upon completion of the testing provides the 
    greatest benefit. Generally, the employee shows the most interest and 
    concern regarding the effects of noise on his/her hearing immediately 
    following testing. Providing the results several weeks or months later 
    may have less of an impact. In many cases, however, it may not be 
    feasible or practical to inform miners immediately of the results of 
    their audiometric tests. The proposal, consequently, would allow mine 
    operators up to 10 working days to inform the miner (the same time 
    period as provided under part 50 for notification of MSHA of cases of 
    reportable hearing loss). Because the proposal would allow up to 30 
    calendar days to evaluate audiograms, it could be as long as 44 days 
    following testing before the miner is informed of the results. In the 
    case of an audiometric retest, it could be as long as 104 days before 
    the miner is informed of the results of the retest. MSHA believes that 
    it is necessary to specify a maximum time frame for informing miners of 
    the audiometric test results in order to prevent undue delays.
    Reporting Noise-Induced Hearing Loss (NIHL)
        Section 62.190(b) of this proposal would require the mine operator 
    to report hearing loss under 30 CFR part 50, if the results of an 
    audiogram or follow-up evaluation indicate that a miner has incurred a 
    ``reportable hearing loss.'' This section is designed to refine, in 
    light of this proposal, MSHA's existing reporting requirements for 
    injuries and illnesses in 30 CFR part 50, so as to ease reporting 
    burdens on employers while promoting the development of an improved 
    data base on hearing loss in the mining community.
        The current reporting requirements provide that mine operators 
    report a hearing loss whenever a physician determines that it is work 
    related, or whenever an award of compensation is made. NIHL is 
    specifically listed among the examples of occupational illnesses to be 
    reported when it is work related. The proposal would establish the 
    reporting definition for this purpose: but the report would only be 
    required under part 50 if the hearing loss is suspected to be work 
    related.
        OSHA does not have reporting requirements: i.e., a level which 
    triggers notification to the agency so that it can intervene. It does, 
    however, have recording requirements for noise, so that information is 
    gathered about NIHL and is available to employers, employees, and 
    agency personnel. In June 1991, OSHA issued its current policy (1991) 
    for reporting NIHL (on the OSHA Form 200). This policy requires 
    employers to record a work-related shift in hearing of 25 dB or more in 
    either ear from the original baseline audiogram averaged over 2000, 
    3000, and 4000 Hz. The recording criteria use identical evaluation 
    frequencies as required for determining an STS. The policy allows a 
    correction for presbycusis when determining reportability. In January 
    1996, OSHA published a proposal to revise agency recordkeeping 
    standards. Under the proposal's mandatory Appendix B, the recording 
    requirement would drop to a work-related shift in hearing of 15 dB or 
    more in either ear. OSHA notes it is proposing this change to ensure 
    the recording of any STS (a 10 dB shift under OSHA's standard), with 
    some allowance made for instrumentation variance.
        In its ANPRM, MSHA discussed the problems that the Agency is 
    experiencing with its existing reporting requirements. Of the 
    commenters addressing this issue, many recommended that MSHA require 
    reporting of a 10-dB average loss in either ear at 2000, 3000, and 4000 
    Hz (the OSHA STS criteria). One commenter favored reporting any job-
    related loss and another stated that the criteria of reporting an STS 
    was too high because ``* * * the worker['s] hearing loss has progressed 
    too far with this shift to be a reliable preventative measure.'' Other 
    commenters stated that the STS criteria represent a slight change in 
    hearing and is not meaningful for reporting purposes. Two commenters 
    recommended that the criteria for reporting be that used for defining 
    impairment (the AAO-HNS 1979 criteria).
        Some hearing conservation associations have opposed OSHA's current 
    policy, arguing that employers should record the NIHL when the employee 
    incurs an STS. Driscoll and Morrill (1987) presented the position of 
    the American Industrial Hygiene Association (AIHA) in a paper entitled 
    ``A Position Paper on a Recommended Criterion for Recording 
    Occupational Hearing Loss on OSHA Form 200''. AIHA concluded that ``a 
    confirmed STS which results from workplace noise exposure is considered 
    an appropriate
    
    [[Page 66446]]
    
    measure for surveillance or recordkeeping purposes.''
        The National Hearing Conservation Association (NHCA) in a letter 
    from their President, Susan Cooper Megerson (1994), to Joseph Dear, 
    Assistant Secretary of Labor for Occupational Safety and Health, urged 
    OSHA to require the recording of an occupational hearing loss when an 
    STS was confirmed. NHCA contends that recording hearing loss after it 
    reaches an average of 25 dB or more at 2000, 3000, and 4000 Hz is 
    ``dangerously underprotective and not technically well founded.''
        Suter (1994) in a letter to Sue Andrei of OSHA's Policy Directorate 
    urged OSHA to adopt a policy of recording persistent occupational 
    hearing loss at an STS instead of at an average of 25 dB or more at 
    2000, 3000, and 4000 Hz.
        MSHA's proposal would define a ``reportable hearing loss'' as a 
    change in hearing threshold relative to the miner's original baseline 
    audiogram of an average of 25 dB or more in either ear at 2000, 3000, 
    and 4000 Hz. If a physician determines that the hearing loss is neither 
    work-related nor aggravated by occupational noise exposure, then it 
    would not be considered a reportable illness under part 50. As 
    discussed in connection with proposed Sec. 62.140, if an audiological 
    exam showed a significant improvement in hearing acuity, the original 
    baseline would be supplemented to reflect this: a correction which 
    would then affect the reportability of hearing loss. Furthermore, as 
    noted in the discussion of proposed Sec. 62.160, the proposal would 
    allow the correction of audiograms for presbycusis when determining the 
    reportability of shifts in hearing threshold levels.
        In selecting its reporting criteria, MSHA took into account that a 
    loss of this magnitude is one that diminishes quality of life and the 
    ability to understand speech in noisy environments. MSHA's reporting 
    criteria, although not impairment per se, represent a substantial loss 
    which would provide a reliable indication of the effectiveness of 
    MSHA's rule and enforcement programs. Moreover, the calculation would 
    be the same as that used to determine an STS and, thus, not an extra 
    burden. The use of other criteria, such as the AAO-HNS 1979 criteria 
    for impairment, would require an additional set of calculations at 
    different frequencies.
        MSHA is concerned, however, that reporting only losses of 25 dB may 
    not provide MSHA a full picture of hearing loss in the mining industry. 
    A loss of 25 dB is used by many states as a basis for making disability 
    awards. Some have recommended that any STS (10 dB loss) should be 
    captured in a hearing loss data base. OSHA, which currently requires 
    any 25 dB loss to be captured in an employer's log, has proposed to 
    capture any 15 dB loss. MSHA accordingly solicits comment on this 
    point.
        An important goal of the proposal is to clarify the level of 
    hearing loss which is reportable. MSHA believes that its current 
    reporting requirements are vague; consequently, cases of NIHL are 
    inconsistently reported or not reported. Some mine operators have 
    reported even a small loss, while others only reported when a miner 
    received an award of compensation. In other cases, mine operators have 
    not reported when an award of compensation was granted because the 
    miners had retired. Inconsistent reporting also results because worker 
    compensation regulations vary from state to state, i.e., the same 
    hearing loss would be compensable and thus reportable in some states 
    and not in others. For these reasons, current hearing loss data 
    reported to MSHA under part 50 cannot be used to accurately 
    characterize either the prevalence or the degree of hearing loss in the 
    mining industry.
        Reporting at a specified level, as required by the proposal, would 
    eliminate reliance on workers' compensation awards as a criteria for 
    defining NIHL to be reported. Nevertheless, part 50 would still require 
    that awards of compensation be reported in those cases when the loss 
    had not been previously reported. Two general examples of such cases 
    are (1) if the miner had incurred the loss before the current mine 
    operator conducted the baseline or pre-employment audiogram and 
    subsequent testing did not measure a reportable loss, and (2) if the 
    miner had not been in an HCP or had not received an audiometric test 
    while employed by the operator.
        In this regard, MSHA would like comment on how to define 
    ``reportable'' hearing loss for those operators who do not have 
    audiometric test data. Not all mine operators will be required to 
    obtain audiometric test data under the proposed rule; thus, such 
    operators may not be able to use a definition of reportable hearing 
    loss defined in this manner. MSHA also requests specific suggestions on 
    how to capture data on work-related NIHL: (1) that is not discovered 
    until after the miner's employment is terminated; and (2) that the 
    miner had accumulated from work with several employers.
        MSHA does not expect mine operators to report the same reportable 
    hearing loss each year that a miner works at the mine. The next 
    reportable hearing loss would not be reported until the miner incurs 
    another 25 dB shift (50 dB shift from the original baseline). MSHA does 
    intend for each ear to be treated independently in terms of a 
    reportable event, unless the reportable loss occurs in both ears during 
    a particular year. (For example, 28.7 dB, left ear, 25.9 dB, right ear, 
    not corrected for presbycusis.) Although not specifically required in 
    its proposal, MSHA anticipates that mine operators would indicate when 
    reporting to MSHA--
        (1) the actual average hearing loss;
        (2) in which ear(s) the loss occurred; and
        (3) whether the audiograms were corrected for presbycusis. (For 
    example, 28.7 dB, left ear, corrected for presbycusis.)
    
    Section 62.200  Access to Records
    
        Authorized representatives of the Secretaries of Labor and Health 
    and Human Services would have immediate access to all records required 
    under this part.
        Moreover under the proposal, a miner or former miner, or his/her 
    designated representative with written consent, would have access to 
    all the records that the mine operator is required to maintain under 
    this part for that individual miner or former miner. Also, the miners' 
    representative is in all cases to have access, for miners they 
    represent, to noise training records and notices required under 
    Sec. 62.120(f) to be given to miners exposed to noise above various 
    levels.
        The mine operator would have 15 days from receipt of a written 
    request to provide such access. The proposal would define ``access'' as 
    the right to examine and copy records. The first copy of any record 
    requested by a person is to be provided without cost to that person, 
    and any additional copies requested by that person are to be provided 
    at reasonable cost.
        Upon termination of employment, mine operators would be required to 
    provide a miner without cost an actual copy of all his/her own records 
    (those required under this part).
        MSHA has no uniform records access provision that address these 
    issues--though the Agency and NIOSH do have statutory rights to access. 
    The provisions proposed here are similar to those in other health 
    standards proposed in recent years by the Agency.
        Section 103(c) of the Mine Act states that:
    
    
    [[Page 66447]]
    
    
        The Secretary, in cooperation with the Secretary of Health, 
    Education, and Welfare, [now Health and Human Services] shall issue 
    regulations requiring operators to maintain accurate records of 
    employee exposures to potentially toxic materials or harmful 
    physical agents which are required to be monitored or measured under 
    any applicable mandatory health or safety standard promulgated under 
    this Act. Such regulations shall provide miners or their 
    representatives with an opportunity to observe such monitoring or 
    measuring, and to have access to the records thereof. Such 
    regulations shall also make appropriate provisions for each miner or 
    former miner to have access to such records as will indicate his own 
    exposure to toxic materials or harmful physical agents.
    
        OSHA's requirements for access to records incorporate its standards 
    for ``Access to Employee Exposure and Medical Records'' [29 CFR 
    Sec. 1910.20(a)-(e) and (g)-(i)]. OSHA's requirements and MSHA's 
    proposal are essentially the same.
        All of the commenters addressing this issue favored providing 
    affected miners with reasonable access to required records. Most of 
    these commenters also recommended that the request for access to 
    records be in writing.
        The Agency agrees, after reviewing comments and related 
    regulations, that access to noise records by both employees and the 
    government is essential, and does not believe the costs of providing 
    such access will be significant. As noted by OSHA, in its preamble to 
    its proposed Hearing Conservation Amendment (46 FR 4161)--
    
        Such access will serve to educate employees as to the state of 
    their hearing and the effectiveness of the program, and will 
    encourage their conscientious participation in it. The information 
    in the records will be invaluable to the Assistant Secretary in the 
    enforcement of the amendment and will be useful in research into the 
    effects of occupational noise exposure. The Director of NIOSH will 
    also be primarily interested in the records for research purposes.
    
        MSHA also agrees that requests from miners, miner's designated 
    representatives, and miner's representatives be in writing. This 
    requirement would benefit both the miners and mine operators by 
    protecting them in matters of dispute regarding the date on which the 
    request was submitted. MSHA's access to records requirements would not 
    preclude the mine operators from requiring the requester to sign a 
    receipt after receiving the records. In addition, the definition of 
    miner's ``designated representative'' specifies that such person have 
    written authorization to request records for each miner or former miner 
    represented. Because requested records may contain personal, private 
    information, MSHA intends that the miner's designated representative 
    would present such authorization to the mine operator when requesting 
    records on behalf of a miner or former miner.
        According to the proposal the mine operator would have 15 days to 
    provide the miner, former miner, or miner's designated representative 
    access to the requested records. MSHA believes that it is reasonable to 
    require the mine operator to provide access because the proposal would 
    require the records to be maintained at the mine site.
        The mine operator has some choice as to how to provide records 
    requested by an employee or representative. The mine operator could 
    provide a copy, make available mechanical copying facilities, or loan 
    the record to the requester for a reasonable time to enable a copy to 
    be made. The proposal provides that if a copy is requested, however, it 
    shall be provided, and the first copy shall be at no cost. If a copy of 
    the record had been provided previously without cost, the proposal 
    would allow the mine operator to charge reasonable, non-discriminatory 
    administrative costs for providing an additional copy of the record. 
    The mine operator, however, could not charge for the first copy of new 
    information which subsequently had been added to the record.
        MSHA believes that its proposed requirements for access to records 
    are both reasonable and necessary to meet its mandate under the Mine 
    Act. MSHA would welcome comments on what actions are required, if any, 
    to facilitate the maintenance of records in electronic form by those 
    mine operators who desire to do so, while ensuring access in accordance 
    with these proposed requirements.
    
    Section 62.210  Transfer of Records
    
        The proposed standard would require mine operators to transfer all 
    records (or a copy thereof) required by this part to any successor mine 
    operator. The successor mine operator would be required to receive 
    these records and maintain them for the period required. Additionally, 
    the successor mine operator would be required to use the baseline 
    audiogram obtained from the original mine operator (or supplemental 
    baseline audiogram as appropriate) for determining an STS and 
    reportable hearing loss.
        MSHA's existing noise standards do not address the transfer of 
    records, nor does MSHA have general standards on this point. The 
    provisions proposed here are similar to those in other health standards 
    proposed in recent years by the Agency. OSHA's standard requires 
    transfer of records and, in addition, incorporates by reference 
    transfer provisions found in its ``Access to Employee Exposure and 
    Medical Records'' standards (29 CFR 1910.20 (h)). MSHA's proposal 
    regarding the transfer of records is essentially the same as in OSHA's 
    regulations.
        MSHA's ANPRM did not address the transfer of records and no 
    comments were received on this subject. MSHA considered OSHA's 
    requirements and believes that they are both reasonable and necessary 
    to ensure that records are maintained for the required periods of time 
    when a mine operator ceases to do business.
        Requiring successor mine operators to use the prior baseline 
    audiogram will provide the miners with a greater degree of protection 
    by assuring that an STS or reportable hearing loss is based on the 
    original or supplemental baseline taken under the original mine 
    operator, instead of based on a new baseline. Generally if a new 
    baseline would be established by a successor mine operator, the miner 
    would need to lose additional hearing acuity before the corrective 
    action triggered by the occurrence of an STS is implemented or a 
    hearing loss is required to be reported.
    
    IV. Feasibility
    
        MSHA has tentatively concluded that it is feasible for the mining 
    industry to take the actions specified in the proposed rule. MSHA has 
    also tentatively concluded that at this time, it may not be feasible 
    for the mining industry to comply with two changes that would otherwise 
    be warranted to further reduce the risk of impairment from occupational 
    NIHL--reducing the PEL to a TWA8 of 85 dBA, and reducing the 
    exchange rate from 5-dB to 3-dB.
        As background, this part begins with a review of the pertinent 
    legal requirements for setting health standards under the Mine Act and 
    an economic profile of the mining industry.
    
    Pertinent Legal Requirements
    
        Section 101(a)(6)(A) of the Mine Act requires the Secretary to set 
    standards which most adequately assure, on the basis of the best 
    available evidence, that no miner will suffer material impairment of 
    health over his/ her working lifetime. In addition, the Mine Act 
    requires that the Secretary, when promulgating mandatory standards 
    pertaining to toxic materials or harmful physical agents, consider 
    other factors, such as the latest scientific data in the field, the 
    feasibility of the standard and experience gained under the Act and 
    other health and safety laws. Thus, the
    
    [[Page 66448]]
    
    Mine Act requires that the Secretary, in promulgating a standard, 
    attain the highest degree of health and safety protection for the 
    miner, based on the ``best available evidence,'' with feasibility a 
    consideration.
        Feasibility in this context refers to both economic and 
    technological feasibility. It also refers to what is feasible for an 
    entire industry, not an individual mine operator; although for this 
    purpose, MSHA has considered independently the situations of the coal 
    mining sector and the metal and nonmetal mining sector.
        In relation to feasibility, the legislative history of the Mine Act 
    states that:
    
        * * * This section further provides that ``other 
    considerations'' in the setting of health standards are ``the latest 
    available scientific data in the field, the feasibility of the 
    standards, and experience gained under this and other health and 
    safety laws.'' While feasibility of the standard may be taken into 
    consideration with respect to engineering controls, this factor 
    should have a substantially less significant role. Thus, the 
    Secretary may appropriately consider the state of the engineering 
    art in industry at the time the standard is promulgated. However, as 
    the circuit court of appeals have recognized, occupational safety 
    and health statutes should be viewed as ``technology-forcing'' 
    legislation, and a proposed health standard should not be rejected 
    as infeasible when the necessary technology looms in today's 
    horizon. (AFL-CIO v. Brennan, 530 F.2d 109); (CA 3 1975) Society of 
    Plastics Industry v. OSHA, 509 F.2d 1301 (CA 2), cert. denied, 427 
    U.S. 992 (1975).
        Similarly, information on the economic impact of a health 
    standard which is provided to the Secretary of Labor at a hearing or 
    during the public comment period, may be given weight by the 
    Secretary. In adopting the language of [this section], the Committee 
    wishes to emphasize that it rejects the view that cost benefit 
    ratios alone may be the basis for depriving miners of the health 
    protection which the law was intended to insure. S. Rep. No. 95-181, 
    95th Cong., 1st Sess. 21 (1977).
    
        Thus, standards may be economically feasible even though industry 
    considers them economically burdensome.
        Though the Mine Act and its legislative history are not specific in 
    defining feasibility, the courts have clarified the meaning of 
    feasibility. The Supreme Court, in American Textile Manufacturers' 
    Institute v. Donovan (OSHA Cotton Dust), 452 U.S. 490, 508-509 (1981), 
    defined the word ``feasible'' as ``capable of being done, executed, or 
    effected.'' The Court stated that a standard would not be considered 
    economically feasible if an entire industry's competitive structure was 
    threatened. According to the Court, the appropriate inquiry into a 
    standard's economic feasibility is whether the standard is capable of 
    being achieved.
        Courts do not expect hard and precise predictions from agencies 
    regarding feasibility. Under the ``arbitrary and capricious standard,'' 
    used in judicial review of agency rulemaking under the Administrative 
    Procedures Act, an agency need only base its predictions on reasonable 
    inferences drawn from the existing facts. An agency is required to 
    produce a reasonable assessment of the likely range of costs that a new 
    standard will have on an industry. The agency must show that a 
    reasonable probability exists that the typical firm in an industry will 
    be able to develop and install controls that will meet the standard. 
    United Steelworkers of America v. Marshall, 647 F.2d 1189 (D.C. Cir. 
    1980).
        In developing a new health standard, an agency must also show that 
    modern technology has at least conceived some industrial strategies or 
    devices that are likely to be capable of meeting the standard, and 
    which industry is generally capable of adopting. United Steelworkers of 
    America v. Marshall, supra at 1272. If only the most technologically 
    advanced companies in an industry are capable of meeting the standard, 
    then that would be sufficient demonstration of feasibility (this would 
    be true even if only some of the operations met the standard for some 
    of the time). American Iron and Steel Institute v. OSHA, 577 F. 2d 825 
    (3d Cir. 1978) at 832-835, see also Industrial Union Dep't., AFL-CIO v. 
    Hodgson, 499 F. 2d 467 (D.C. Cir. 1974).
        In evaluating the feasibility of particular requirements under 
    these legal tests, MSHA took into account how it anticipates 
    interpreting those requirements. For example, in the case of the 
    requirement that mine operators use all feasible engineering and 
    administrative controls, the Agency considered legal guidance from the 
    Federal Mine Safety and Health Review Commission as to what MSHA must 
    consider, for enforcement purposes, as a feasible noise control at a 
    particular mine. This guidance is discussed in the ``Questions and 
    Answers'' in part I (see Question 12). MSHA also used its expert 
    knowledge of particular equipment or methods of noise control available 
    in the industry, and considered exposure data indicating the extent to 
    which the industry would be out of compliance should a particular 
    proposal be adopted.
    
    Industry Profile
    
        Determining the feasibility of controls for the mining sector 
    requires consideration of the composition and economics of that sector. 
    The following information is reprinted from MSHA's preliminary 
    Regulatory Impact Analysis (RIA), and was considered by the Agency in 
    reaching preliminary conclusions.
    
    Overall Structure of the Mining Industry
    
        MSHA divides the mining industry into two major segments based on 
    commodity, the coal mining industry and the metal and nonmetal mining 
    industry. These major industry segments are further divided based on 
    type of operation (underground mines, surface mines, and independent 
    mills, plants, shops, and yards). MSHA maintains its own data on mine 
    type, size, and employment. MSHA also collects data on the number of 
    contractors and contractor employees by major industry segment.
        MSHA categorizes mines as to size based on employment. For the 
    purpose of analyzing this proposed rule, MSHA defines small mines to be 
    those having fewer than 20 employees and large mines to be those having 
    at least 20 employees. Table IV-1 presents the number of small and 
    large mines and the corresponding number of miners, excluding 
    contractors, by major industry segment and mine type. Although MSHA 
    does not maintain a data base of the numbers of miners by job title, 
    Table IV-2 presents an estimate of the numbers of miners by job title 
    groups based in part on research conducted by the U.S. Department of 
    the Interior, Bureau of Mines. The Agency does not maintain a data base 
    which would allow determination of the types of services provided by 
    independent contractors or the job titles of contractor employees. 
    Table IV-3, however, presents MSHA data on the numbers of independent 
    contractors and the corresponding numbers of employees by major 
    industry segment and the size of the operation based on employment.
    
    [[Page 66449]]
    
    
    
    Table IV-1.--Distribution of Operations and Employment (Excluding Contractors) by Mine Type, Commodity, and Size
    ----------------------------------------------------------------------------------------------------------------
                                             Small (<20 ees)="" large="" (="">20 EES)                Total         
                                       -----------------------------------------------------------------------------
                 Mine type               Number of    Number of    Number of    Number of    Number of    Number of 
                                           mines        miners       Mines        Miners       Mines        Miners  
    ----------------------------------------------------------------------------------------------------------------
    Coal:                                                                                                           
        Underground...................          466        4,630          606       49,370        1,072       54,000
        Surface.......................          875        5,337          396       30,173        1,271       35,510
        Shp/Yrd/Mll/Plnt..............          421        2,701          132        5,169          553        7,870
        Office workers................  ...........          752  ...........        5,030  ...........        5,782
                                       -----------------------------------------------------------------------------
        Coal Subtotal.................        1,762       13,420        1,134       89,742        2,896      103,162
                                       =============================================================================
    Metal/nonmetal (M/NM):                                                                                          
        Underground...................          141        1,191          134       16,736          275       17,927
        Surface.......................        8,838       49,214        1,192       79,230       10,030      128,444
        Shp/Yrd/Mll/Plnt..............          288        2,146          223       18,889          511       21,035
        Office workers................  ...........        8,530  ...........       18,644  ...........       27,174
                                       -----------------------------------------------------------------------------
        M/NM Subtotal.................        9,267       61,081        1,549      133,499       10,816      194,580
                                       =============================================================================
                Total all mines.......       11,029       74,501        2,683      223,241       13,712      297,742
    ----------------------------------------------------------------------------------------------------------------
    Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and  
      Variances, based on preliminary 1995 MIS data (quarter 1-quarter 4, 1995). MSHA estimates assume that operator
      office workers are distributed the same as non-office workers.                                                
    
    
     Table IV-2.--Mining Workforce Estimates by Job Title Groups (Including Office Workers and Excluding Contractor 
                                                       Employees)                                                   
    ----------------------------------------------------------------------------------------------------------------
                                               Coal mining               M/NM mining                  Total         
             Job title groups          -----------------------------------------------------------------------------
                                          Percent       Miners      Percent       Miners      Percent       Miners  
    ----------------------------------------------------------------------------------------------------------------
    Backhoe-crane-dragline-shovel                                                                                   
     operator.........................          1.9        2,004          2.5        4,938          2.3        6,942
    Beltman-belt cleaner (coal)-belt                                                                                
     repairman........................          3.4        3,473          0.4          800          1.4        4,273
    Blaster...........................          0.8          810          0.3          605          0.5        1,415
    Continuous miner & related machine                                                                              
     operator.........................          4.2        4,282        (\1\)        (\1\)          1.4        4,282
    Deckhand-barge & dredge operator..          0.2          156          0.6        1,103          0.4        1,259
    Dozer-heavy & mobile equipment                                                                                  
     operator.........................          6.8        7,038          2.7        5,289          4.1       12,326
    Driller-auger operator (coal)-rock                                                                              
     bolter (m/nm)....................          1.9        1,910          1.9        3,700          1.9        5,611
    Electrician-wireman (coal)-lampman          4.0        4,127          1.9        3,780          2.7        7,908
    Front-end loader-forklift (m/nm)                                                                                
     operator.........................          2.8        2,876          7.2       13,943          5.7       16,820
    Grader-scraper operator...........          1.6        1,636          0.7        1,323          1.0        2,959
    Laborer-miner-utility man.........         15.0       15,477         10.3       20,021         11.9       35,498
    Longwall operator.................          0.7          689        (\1\)        (\1\)          0.2          689
    Manager-foreman-supervisor........         11.1       11,423         10.1       19,685         10.5       31,108
    Mechanic-welder-oiler-machinist...         15.0       15,457         14.7       28,546         14.8       44,003
    Mine technical support............          4.4        4,521          6.7       13,039          5.9       17,561
    Office workers....................          5.6        5,782         14.0       27,174         11.1       32,956
    Plant operator-warehouseman.......          3.8        3,921         14.0       27,315         10.5       31,236
    Roof bolter-rock driller (coal)...          5.3        5,459            0            0          1.8        5,459
    Scoop tractor operator-motorman                                                                                 
     (coal)...........................          3.4        3,510            0            0          1.2        3,510
    Shuttle car-tram (m/nm) operator..          3.6        3,756          0.8        1,607          1.8        5,363
    Stone cutter-finisher.............            0            0          0.5          879          0.3          879
    Truck driver......................          4.7        4,854         10.7       20,832          8.6       25,686
                                       -----------------------------------------------------------------------------
          Total.......................          100      103,162          100      194,580          100     297,742 
    ----------------------------------------------------------------------------------------------------------------
    \1\ Continuous miner and longwall operators at metal/nonmetal mines are included in the job group ``laborer-    
      miner-utility man.''                                                                                          
    Extrapolated from U.S. Bureau of Mines, Characterization of the 1986 Coal Mining Workforce (IC 9192) and        
      Characterization of the 1986 Metal and Nonmetal Mining Workforce (IC 9193), 1988.                             
    
    
      Table IV-3.-- Distribution of Contractors (Contr) and Contractor Employees (Miners) by Major Industry Segment 
                                                  and Size of Operation                                             
    ----------------------------------------------------------------------------------------------------------------
                                               Small (<20) large="">20)             Total         
                                       -----------------------------------------------------------------------------
                Contractors              Number of    Number of    Number of    Number of    Number of    Number of 
                                           contr.       miners       contr.       miners       contr.       miners  
    ----------------------------------------------------------------------------------------------------------------
    Coal:                                                                                                           
        Other than office.............        3,580       14,310          291       12,863        3,871       27,173
    
    [[Page 66450]]
    
                                                                                                                    
        Office workers................  ...........        1,291  ...........        1,160  ...........        2,451
                                       -----------------------------------------------------------------------------
          Coal Subtotal...............        3,580       15,601          291       14,023        3,871       29,624
                                       =============================================================================
    Metal/nonmetal (M/NM):                                                                                          
        Other than office.............        2,656       12,921          352       20,975        3,008       33,896
        Office workers................  ...........          734  ...........        1,191  ...........        1,925
        M/NM Subtotal.................        2,656       13,655          352       22,166        3,008       35,821
                                       -----------------------------------------------------------------------------
          Total.......................        6,236       29,256          643       36,189        6,879      65,445 
    ----------------------------------------------------------------------------------------------------------------
    Source: U.S. Department of Labor, Mine Safety and Health Administration, Office of Standards, Regulations, and  
      Variances, based on preliminary 1995 MIS data (quarter 1-quarter 4, 1995). MSHA estimates assume that         
      contractor office workers are distributed the same as non-office workers.                                     
    
    Economic Characteristics
    
        The U.S. mining industry's 1995 production is worth in excess of 
    $58 billion in raw mineral resources. Coal mining contributed about $20 
    billion to the Gross Domestic Product in 1995 and metal and nonmetal 
    mining contributed about $38 billion. Another $17 billion is reclaimed 
    annually from recycled metal and mineral materials such as scrap iron, 
    aluminum, and glass.
        The Agency obtained financial information on the various mineral 
    commodities primarily from the U.S. Department of the Interior, Bureau 
    of Mines, and the U.S. Department of Energy, Energy Information 
    Administration.
    
    Structure of the Coal Mining Industry
    
        MSHA separates the U.S. coal mining industry into two major 
    commodity groups, bituminous and anthracite. The bituminous group 
    includes the mining of subbituminous coal and lignite. Bituminous 
    operations represent over 93% of the coal mining operations, employ 
    over 98% of the coal miners, and account for over 99% of the coal 
    production. About 60% of the bituminous operations are large; whereas 
    about 90% of the anthracite operations are small.
        Underground bituminous mines are more mechanized than anthracite 
    mines in that most, if not all, underground anthracite mines still 
    hand-load. Over 70% of the underground bituminous mines use continuous 
    mining and longwall mining methods. The remaining use drills, cutters, 
    and scoops. Although underground coal mines generally use electrical 
    equipment, a growing number of underground coal mines use diesel 
    haulage equipment.
        Surface mining methods include drilling, blasting, and hauling and 
    are similar for all commodity types. Most surface mines use front-end 
    loaders, bulldozers, shovels, or trucks for coal haulage. A few still 
    use rail haulage. Although some coal may be crushed to facilitate 
    cleaning or mixing, coal processing usually involves cleaning, sizing, 
    and grading.
        Preliminary data for 1995 indicate that there are about 2900 active 
    coal mines of which 1760 are small mines (about 61% of the total) and 
    1130 are large mines (about 39% of the total).
        These data indicate employment at coal mines to be about 103,200 of 
    which about 13,400 (13% of the total) worked at small mines and 89,700 
    (87% of the total) worked at large mines. MSHA estimates that the 
    average employment is 8 miners at small coal mines and 79 miners at 
    large coal mines.
    
    Structure of the Metal/Nonmetal Mining Industry
    
        The metal and nonmetal mining industry consists of about 70 
    different commodities including metals, industrial minerals, stone, and 
    sand and gravel. Preliminary data for 1995 indicate that there are 
    about 10,820 active metal and nonmetal mines of which 9270 are small 
    mines (about 86% of the total) and 1550 are large mines (about 14% of 
    the total).
        These data indicate employment at metal and nonmetal mines to be 
    about 194,600 of which about 61,100 (31% of the total) worked at small 
    mines and 133,500 (69% of the total) worked at large mines. MSHA 
    estimates that the average employment is 7 miners at small metal and 
    nonmetal mines and 86 miners at large metal and nonmetal mines. Table 
    II-4 presents the number of metal and nonmetal mines and miners by 
    major commodity category, mine size, and employment. In addition, MSHA 
    estimates that about 350 mines are owned by state, county, or city 
    governments.
    
                        Table IV-4.--Estimated Distribution of Metal/Nonmetal Mines and Miners 1                    
    ----------------------------------------------------------------------------------------------------------------
                                             Small (<20 ees)="" large="" (="">20 EES)                Total         
                                       -----------------------------------------------------------------------------
                 Commodity               Number of    Number of    Number of    Number of    Number of    Number of 
                                           Mines        Miners       Mines        Miners       Mines        Miners  
    ----------------------------------------------------------------------------------------------------------------
    Metal.............................          176        1,199          193       46,296          369       47,495
    Nonmetal..........................          546        3,496          231       25,436          777       28,932
    Stone.............................        2,640       23,003          894       53,157        3,534       76,160
    Sand and Gravel...................        5,905       33,383          231        8,610        6,136       41,993
                                       -----------------------------------------------------------------------------
          Total.......................        9,267       61,081        1,549      133,499       10,816     194,580 
    ----------------------------------------------------------------------------------------------------------------
    1 Includes office workers. Excludes contractors.                                                                
    
    
    [[Page 66451]]
    
    Metal Mining
        Metal mining in the U.S. consists of about 25 different 
    commodities. Most metal commodities include only one or two mining 
    operations. Metal mining operations represent about 3% of the metal and 
    nonmetal mines, employ about 24% of the metal and nonmetal miners, and 
    account for about 35% of the value of metal and nonmetal minerals 
    produced in the U.S. About 48% of the metal mining operations are 
    small.
        Underground metal mining uses a few basic mining methods, such as 
    stope, room and pillar, and block caving with primary noise sources 
    being diesel haulage equipment, pneumatic drills, and mills. Larger 
    underground metal mines use more hydraulic drills and track-mounted 
    haulage; whereas, smaller underground metal mines use more hand-held 
    pneumatic drills. Stope mining uses more hand-held equipment. Surface 
    metal mines include some of the largest mines in the world. Surface 
    mining methods (drill, blast, haul) use the largest equipment and are 
    similar for all commodity types.
    Nonmetal Mining
        For enforcement and statistical purposes, MSHA separates stone and 
    sand and gravel mining from other nonmetal mining. There are about 35 
    different nonmetal commodities, not including stone or sand and gravel. 
    About half of the nonmetal commodities include less than 10 mining 
    operations; some include only one or two mining operations. Nonmetal 
    mining operations represent about 7% of the metal and nonmetal mines, 
    employ about 15% of the metal and nonmetal miners, and account for 
    about 34% of the value of metal and nonmetal minerals produced in the 
    U.S. About 70% of the nonmetal mining operations are small.
        Nonmetal mining uses a wide variety of underground mining methods. 
    For example, potash mines use continuous miners similar to coal mining; 
    oil shale uses in-situ retorting; and gilsonite uses hand-held 
    pneumatic chippers. Some nonmetal commodities use kilns and dryers in 
    ore processing. Others use crushers and mills similar to metal mining. 
    Underground nonmetal mining operations generally use more block caving, 
    room and pillar, and retreat mining methods; less hand-held equipment; 
    and more electrical equipment than metal mining operations. As with 
    underground mining, surface mining methods vary more than for other 
    commodity groups. In addition to drilling, blasting, and hauling, 
    surface nonmetal mining methods include other types of mining methods, 
    such as evaporation beds and dredging.
    Stone Mining
        There are basically only eight different stone commodities of which 
    seven are further classified as either dimension stone or crushed and 
    broken stone. Stone mining operations represent about 33% of the metal 
    and nonmetal mines, employ about 39% of the metal and nonmetal miners, 
    and account for about 19% of the value of metal and nonmetal minerals 
    produced in the U.S. About 75% of the stone mining operations are 
    small.
        Stone generally is mined from quarries using only a few different 
    methods and diesel haulage to transfer the ore from the quarry to the 
    mill. Crushed stone mines typically drill and blast; whereas, dimension 
    stone mines typically use channel burners, drills, or wire saws. 
    Milling typically includes jaw crushers, vibratory crushers, and 
    vibratory sizing screens.
    Sand and Gravel Mining
        Based on the number of mines, sand and gravel mining represents the 
    single largest commodity group in the U.S. mining industry. About 57% 
    of the metal and nonmetal mines are sand and gravel operations. They 
    employ about 22% of the metal and nonmetal miners and account for about 
    11% of the value of metal and nonmetal minerals produced in the U.S. 
    Over 95% of the sand and gravel operations are small.
        Construction sand and gravel is generally gathered from surface 
    deposits using dredges or draglines and only washing and screening 
    milling methods. As in other surface mining operations, sand and gravel 
    uses diesel haulage equipment, such as front-end loaders, trucks, and 
    bulldozers. In addition, industrial sand and silica flour operations 
    mill the ore using crushers, ball mills, screens, and classifiers.
    
    Economic Characteristics of the Coal Mining Industry
    
        The U.S. Department of Energy, Energy Information Administration, 
    reported that the U.S. coal industry produced a record 1.03 billion 
    tons of coal in 1994 with a value of about $20 billion. Of the several 
    different types of coal commodities, bituminous and subbituminous coal 
    account for 91% of all coal production (940 million tons). The 
    remainder of U.S. coal production is lignite (86 million tons) and 
    anthracite (4 million tons). Although anthracite offers superior 
    burning qualities, it contributes only a small and diminishing share of 
    total coal production. Less than 0.4% of U.S. coal production in 1994 
    was anthracite.
        Mines east of the Mississippi account for about 53% of the current 
    U.S. coal production. For the period 1949 through 1995, coal production 
    east of the Mississippi River fluctuated relatively little from a low 
    of 395 million tons in 1954 to 630 million tons in 1990. (It was 568 
    million tons in 1994.) During this same period, however, coal 
    production west of the Mississippi increased each year from a low of 20 
    million tons in 1959 to a record 490 million tons in 1995. The growth 
    in western coal is due in part to environmental concerns that led to 
    increased demand for low-sulfur coal, which is concentrated in the 
    West. In addition, surface mining, with its higher average 
    productivity, is much more prevalent in the West.
        Preliminary MSHA data for 1995 indicate that small mines produced 
    about 4% of the total coal mine production (about 44 million tons) and 
    large mines produced about 96% of the total (983 million tons). MSHA 
    calculations indicate that the average total production per miner for 
    1995 was about 3,500 tons at small mines and 11,400 tons at large 
    mines. The average total coal production for 1995 was about 25,000 tons 
    per small mine and 867,000 tons per large mine.
        The 1994 estimate of the average value of coal at the point of 
    production is about $19 per ton for bituminous coal and lignite, and 
    $36 per ton for anthracite. MSHA chose to use $19 per ton as the value 
    for all coal production because anthracite contributes such a small 
    amount to total production that the higher value per ton of anthracite 
    does not greatly impact the total value. The total value of coal 
    production in 1995 was about $20 billion of which about $0.9 billion 
    was produced by small mines and $19.1 billion was produced by large 
    mines. On a per mine basis, the average coal production was valued at 
    $0.5 million per small mine and $17 million per large mine.
        Coal is used for several purposes including the production of 
    electricity. The predominant consumer of coal is the U.S. electric 
    utility industry which used 829 million tons of coal in 1995 or 80% of 
    the coal produced. Other coal consumers include coke plants (33 million 
    tons), residential and commercial consumption (6 million tons), and 
    miscellaneous other industrial uses (73 million tons). This last 
    category includes the use of coal products in the manufacturing of 
    other products, such as plastics, dyes, drugs, explosives, solvents, 
    refrigerants, and fertilizers.
    
    [[Page 66452]]
    
        The current rate of U.S. coal production exceeds U.S. consumption 
    by roughly 90 million tons annually. In 1995, 89 million tons of this 
    excess production was exported and the remainder was stockpiled. Japan 
    (11.8 million tons), Canada (9.4 million tons), and Italy (9.1 million 
    tons) were the top three importers of U.S. coal. Year-to-year 
    fluctuations in exports of U.S. coal vary more than domestic 
    consumption. During the 1990's, changes in exports from the previous 
    year varied from a 24% increase to a 27% decrease; whereas, changes in 
    domestic consumption only varied from a 4% increase to a 1% decrease.
        The U.S. coal industry enjoys a fairly constant domestic demand. 
    Its demand by electric utilities continues to increase annually. MSHA 
    does not expect a substantial change in coal demand by utilities in the 
    near future because of the high conversion costs of changing a fuel 
    source in the electric utility industry. Energy experts predict that 
    coal will continue to be the dominant fuel source of choice for power 
    plants built in the future. Nuclear and hydropower currently comprise, 
    and are anticipated in the future to comprise, a small fraction of fuel 
    sources for utilities.
        The international market for coal was marked by several notable 
    events in the 1990's. The breakup of the Soviet Union (USSR), a new 
    political regime in South Africa, and economic policy changes in the 
    United Kingdom and Germany contributed to price and demand changes in 
    coal's global marketplace; newly independent, former USSR republics 
    provided competition to U.S. companies for a share of the European coal 
    market; and the deep European recession of 1993-1994 caused exports of 
    coal to decrease. Similarly, the cessation of the economic boycott of 
    South Africa, and its new political leadership, has led to new interest 
    in South African exports. South Africa ranks third after Australia and 
    the U.S. in coal exports. Its coal exploration and mining have the 
    nation poised to maintain its global position. The privatization of 
    British power companies and the elimination of coal subsidies in 
    Germany have led to an increased interest in U.S. coal. These 
    international economic policy changes are predicted to create a 
    substantial export opportunity for U.S. coal over the long term.
        The net effect of these aforementioned international activities 
    appears to be a continued demand for U.S. coal at or near current 
    level. The U.S. can expect additional competition, however, from other 
    current coal producing countries (e.g., Australia, South Africa, former 
    USSR republics, Poland), as well as from new suppliers in Colombia, 
    Venezuela, China, and Indonesia. The U.S. coal industry has vast 
    reserves of unmined coal which is predicted to sustain coal's demand 
    for another half millennium if mined at the current rate.
        The economic health of the coal industry may be summarized as a 
    fairly stable market which may be subject to periodic price and demand 
    fluctuations. These fluctuations are largely functions of domestic 
    supply disruptions and increased international competition. The 1993 
    average profit as a percent of revenue for the coal mining industry was 
    about 3-4% after taxes.
    
    Economic Characteristics of the Metal and Nonmetal Mining Industry: 
    Summary
    
        The 1995 value of all metal and nonmetal mining output is about $38 
    billion. Metal mining contributes $13.2 billion to this total and 
    includes metals such as aluminum, copper, gold, and iron. Nonmetal 
    mining is valued at $12.9 billion and includes commodities such as 
    cement, clay, and salt. Stone mining contributes about $7.2 billion and 
    sand and gravel contributes about $4.3 billion to this total.
        The entire metal and nonmetal mining industry is markedly diverse 
    not only in terms of the breadth of minerals, but also in terms of each 
    commodity's usage. For example, metals such as iron and aluminum are 
    used to produce vehicles and other heavy duty equipment, as well as 
    consumer goods such as household equipment and soda pop cans. Other 
    metals, such as uranium and titanium, have limited uses. Nonmetals like 
    cement are used in construction while salt is used as a food additive 
    and on roads in the winter. Soda ash, phosphate rock, and potash also 
    have a wide variety of commercial uses. Stone and sand and gravel are 
    used in numerous industries including the construction of roads and 
    buildings.
        A detailed economic picture of the metal and nonmetal mining 
    industry is difficult to develop because most mines are either 
    privately held corporations or sole proprietorships, or subsidiaries of 
    publicly owned companies. Privately held corporations and sole 
    proprietorships do not make their financial data available to the 
    public. Further, parent companies are not required to separate 
    financial data for subsidiaries in their reports to the Securities and 
    Exchange Commission. As a result, financial data are available for only 
    a few metal and nonmetal companies and these data are not 
    representative of the entire industry. Each commodity has a unique 
    market demand structure. The following discussion focuses on market 
    forces on a few specific commodities of the metal and nonmetal 
    industry.
    Metal Mining
        Historically, the value of metals production has exhibited 
    considerable instability. In the early 1980's, excess capacity, large 
    inventories, and weak demand depressed the international market for 
    metals while the strong dollar placed U.S. producers at a competitive 
    disadvantage with foreign producers. Reacting to this, many metal 
    mining companies reduced work forces, eliminated marginal facilities, 
    sold non-core businesses, and restructured. At the same time, new 
    mining technologies were developed and wage increases were restrained. 
    As a result, the metal mining firms now operating are more efficient 
    and have lower break-even prices than those that operated in the 
    1970's.
        For the purposes of this analysis, MSHA uses the Standard and 
    Poor's methodology of dividing metal mining into two categories: iron 
    ore and alloying metals, and copper and precious metals. Metal mine 
    production is valued in excess of $13 billion. Copper, aluminum, gold, 
    and iron are the highest revenue producers of the metal industry.
        Variations in the prices for iron and alloying metals, such as 
    nickel, aluminum, molybdenum, vanadium, platinum, and lead, coincide 
    closely with fluctuations in the market for durable goods, such as 
    vehicles and heavy duty equipment. As a result, the market for these 
    metals is cyclical in nature and is impacted directly by changes in 
    aggregate demand and the economy in general.
        Both nickel and aluminum have experienced strong price fluctuations 
    over the past few years; however, with the U.S. and world economies 
    improving, demand for such alloys is improving and prices have begun to 
    recover. It must be noted that primary production of aluminum will 
    continue to be impacted by the push to recycle. Recycling of aluminum 
    now accounts for 30% of the aluminum used and this percent is expected 
    to rise in the coming years. Due to the increase in aluminum recycling, 
    prices have been falling and inventories rising since the mid to late 
    1980's.
        The market for copper and precious metals, such as gold and silver, 
    is marked by great uncertainty and price volatility. Prices for gold 
    and silver fluctuated by as much as 17 to 25%, respectively, during 
    1993. The copper market recovered substantially during
    
    [[Page 66453]]
    
    1994, posting a 3.7% growth in demand by 1995. The gold and silver 
    markets, however, continue to be marred with speculative demand spurs; 
    consistent recovery and growth have been difficult to achieve due to 
    uncertainty of U.S. buyers and shifts in production in South Africa and 
    Russia. In 1993, Russia began to cut back its gold production which had 
    generated low prices in the global market since 1990.
        Overall, the production from metal mining increased by about 5.5% 
    from 1987 to 1995; 1995 estimates put capacity utilization at 84%. MSHA 
    expects that the net result for the metal mining industry may be 
    reduced demand but sustained prices. The 1993 average profit as a 
    percent of revenue for the metal mining industry was about a 1.3% loss 
    after taxes.
    Nonmetal Mining, Including Stone and Sand and Gravel
        Nonmetal mine production is valued at more than $24 billion. 
    Included in this figure is the production of granite, limestone, 
    marble, slate, and other forms of crushed and broken or dimension 
    stone. Other prosperous commodities in the nonmetal category include 
    salt, clay, phosphate rock, and soda ash. Market demand for these 
    products tends not to vary greatly with fluctuations in aggregate 
    demand. Stone is the leading revenue generator with 1994 production 
    valued at $7.2 billion. Construction sand and gravel and industrial 
    sand 1995 production is valued at about $4.3 billion.
        Evaluating financial information for nonmetal mining operations is 
    particularly difficult. Financial data are available only for 
    relatively large mining operations and these often engage in a wide 
    variety of activities of which mining is typically only a small part. 
    Many large mining firms have financial interests in mines or mills of 
    different commodities, thereby making it difficult to evaluate the 
    financial aspects of any specific commodity. Publicly held firms are 
    not required to separate financial data for their subsidiaries in their 
    reports to the Securities and Exchange Commission and financial data 
    are not available for most of the small mines because they are not 
    publicly owned. (About 98% of the small metal and nonmetal mining 
    operations are stone, sand and gravel, or other nonmetal operations.) 
    This discussion of the economic characteristics of the nonmetal mining 
    industry does not separately address sand and gravel, stone, and 
    miscellaneous other nonmetal mining operations as was done in the 
    discussion of the nonmetal mining industry's structure.
        Sand and gravel and stone products, including cement, have a 
    cyclical demand structure. As a recession intensifies, demand for these 
    products sharply decreases. Some stability in the market was achieved 
    during 1993 and early 1994. Demand for stone, particularly cement, is 
    expected to grow by as much as 4.8% and demand for sand and gravel is 
    expected to grow by as much as 2.3%.
        The U.S. is the largest soda ash producer in the world with its 
    1994 production valued at about $650 million. Soda ash is used in the 
    production of glass, soap and detergents, paper, and food. Both salt 
    and soda ash have a fairly constant demand structure due to the 
    products' uses and the lack of suitable substitutes. A 1994 industry 
    analysis indicates shifts in the world demand for salt. European 
    demand, impelled by the economic breakdown of Central and Eastern 
    Europe, has declined; however, growth in demand has increased in Asia 
    and the Far East.
        Phosphate rock, which is used primarily to manufacture fertilizer, 
    has an unusual market structure. U.S. production and exports of 
    phosphate rock have declined in recent years and imports from Morocco 
    increased by 180% from 1991 to 1992.
        The remaining nonmetal commodities which include boron fluorspar, 
    oil shale, and other minerals are produced typically by a small number 
    of mining operations. Despite this fact, annual production of pumice, 
    perlite, vermiculite, and some others is valued at the tens of millions 
    of dollars for each product.
        Overall, the production from nonmetal mining remained relatively 
    stable from 1987 to 1995; 1995 estimates put capacity utilization for 
    stone and earth minerals at about 97%. The net result for the nonmetal 
    mining industry may be higher demand for stone and various other 
    commodities and increased prices. The 1993 average profit as a percent 
    of revenue was about 3-4% for nonmetal mine production, excluding stone 
    and sand and gravel; about 8% for stone mining; and about 5% for sand 
    and gravel.
    
    Feasibility of Requiring the Use of Engineering and Administrative 
    Controls at a TWA8 of 90 dBA
    
        In this proposal, MSHA has determined that the Mine Act's objective 
    to protect miners from material impairment of health can be met by 
    requiring mine operators to use all feasible engineering and 
    administrative controls. This approach is close to that already 
    required in the metal and nonmetal sector of the industry. In the coal 
    sector, attenuation of hearing protectors have been considered in 
    determining compliance with the PEL, and in practice this has meant 
    that few mine operators have had to institute engineering or 
    administrative controls.
        The approach gives mine operators flexibility to choose those 
    controls or combinations of controls which would be the most effective 
    in reducing exposure to noise. If the institution of administrative 
    controls does not adequately protect the miners in a given work 
    situation, MSHA will require the implementation of feasible engineering 
    controls. Under this approach, the Agency has to determine in the 
    particular situation that the proposed engineering controls are 
    feasible prior to requiring their implementation. Likewise, if the 
    engineering controls prove inadequate, the Agency will require the 
    implementation of feasible administrative controls.
        In the metal and nonmetal industry where this approach is currently 
    implemented, smaller operations predominate. As a result, 
    administrative controls are seldom feasible, and engineering controls 
    may not be economically feasible for some operations. Moreover, given 
    the technology available in this sector, in a few cases complete 
    engineering solutions may not be technologically feasible. However 
    based on the information on available controls reviewed in part III, 
    including methods developed by the former Bureau of Mines, MSHA 
    believes there are few cases in which noise cannot be significantly 
    reduced through some sort of engineering control (including miner 
    isolation). The Agency has specifically solicited comments on the 
    feasibility of controls for metal and nonmetal equipment and operations 
    identified as generating sound levels above a TWA8 of 105 dBA; as 
    noted in part III, exposures exceeding this level constitute less than 
    one-quarter of one percent of all exposures, and many mine operators do 
    manage to control the exposures from such equipment. And the Agency 
    welcomes comments on other specific feasibility concerns. Based on its 
    review, MSHA believes most metal and nonmetal mine operators will find 
    feasible engineering controls that meet their requirements.
        In the coal industry, many mine operators are larger and the 
    technology is different. Many coal mine operators are large enough to 
    be able to use administrative controls where engineering controls are 
    not economically feasible. Moreover, based
    
    [[Page 66454]]
    
    on the information reviewed in part III, MSHA is confident that 
    engineering solutions are available that can significantly reduce noise 
    in almost all situations in which coal mining noise exceeds the PEL. 
    Moreover, the Agency notes that the available engineering solutions are 
    constantly changing--for example, it may be easier today than it used 
    to be to find retrofit cabs for older equipment. Even in problem areas 
    like coal preparation plants and highwall areas there are available 
    solutions. In coal preparation plants, motor enclosures, operator 
    control booths, material dampening of chutes and transfer points, and 
    process area enclosures can bring about significant reductions in 
    exposure; for highwall areas, exhaust mufflers and compressor barriers 
    can do the same. The Agency would be interested in comments on problems 
    encountered in controlling noise in coal operations and on solutions 
    that have proved effective.
        In concluding that such requirements are feasible in the mining 
    industry, MSHA takes into account that the proposed rule would require 
    a mine operator to use all feasible engineering and administrative 
    controls. On the one hand this means that MSHA will require mine 
    operators to consider all possible controls so as to find a combination 
    that will in fact reduce noise as much as possible. MSHA's enforcement 
    policy in this regard has been noted earlier in this section (and in 
    the Question and Answer section in part I). On the other hand, there 
    may be situations where no combination of engineering and 
    administrative controls to reduce exposures to the PEL is economically 
    or technologically feasible. In such cases, the proposed standard 
    specifies the other actions a mine operator must take to protect 
    workers to the maximum extent possible--including the use of 
    engineering and administrative controls to reduce exposures to the 
    maximum extent that is feasible.
        Following is further discussion of the feasibility of 
    administrative controls and engineering controls, respectively.
    
    Feasibility of Administrative Controls
    
        Administrative controls refers to the practice of limiting the 
    exposure of individual miners to a noise source. Administrative 
    controls reduce exposure through such actions as rotation of miners to 
    areas having lower sound levels, rescheduling of tasks, modifying work 
    activities, or limiting the amount of time that a miner is exposed to 
    noise.
        The feasibility of administrative controls to solve particular 
    noise problems in any mine may be limited by a number of factors: 
    limitations on the number of qualified miners capable of handling a 
    specific task, labor/management agreements affecting duty assignments, 
    or difficulty in ensuring that miners adhere to the administrative 
    controls. Further, because the effectiveness of administrative controls 
    is based on adherence to these strict time periods, mine operators may 
    find it difficult to verify compliance with the administrative 
    procedures.
        As explained in the discussion of proposed Sec. 62.120(c), it is 
    MSHA's experience that administrative controls are relatively more 
    feasible for mines with many employees and relatively less feasible for 
    mines with fewer employees. As demonstrated by the industry profile, 
    the mines in the coal industry are generally larger mines. It is MSHA's 
    experience that many coal mine operators may prefer administrative 
    controls as the primary noise control. This is, in fact, the reasons 
    proposed Sec. 62.120(c) was designed to preserve mine operator choice. 
    The use of such controls is much less feasible in the smaller mines 
    that characterize the metal and nonmetal industry.
    
    Feasibility of Engineering Controls
    
        If administrative controls are not feasible, or cannot by 
    themselves reduce noise to the PEL, mine operators are to use all 
    feasible engineering controls. This discussion is divided into two 
    parts: the technological feasibility of such controls, and the economic 
    feasibility of such controls.
    Technological Feasibility of Engineering Controls
        MSHA is an active and knowledgeable partner in continually refining 
    and improving existing noise control technology. At the request of 
    MSHA's Coal Mine Safety and Health or Metal and Nonmetal Mine Safety 
    and Health, MSHA's Technical Support actively assists mine operators in 
    developing noise controls. Based upon this knowledge, and MSHA's 
    experience, the Agency has determined that feasible engineering 
    controls exist for the majority of equipment used in mining.
        MSHA has evaluated under actual mining conditions newly developed 
    noise controls for surface self-propelled equipment, underground diesel 
    powered haulage equipment, jumbo drills, track drills, hand-held 
    percussive drills, draglines/shovels, portable crushers, channel 
    burners, and mills, and has found them to be effective in reducing 
    miners' noise exposure. Some of these feasible engineering controls are 
    already designed into new equipment. In many cases, effective and 
    feasible controls are available through retrofitting or the proper use 
    of noise barriers. A more detailed discussion regarding the 
    availability of these controls is contained in part III of this 
    preamble (see Engineering Noise Controls for Mining Equipment, in the 
    discussion of proposed Sec. 62.120(c) in part III). Part V of this 
    preamble contains a list of publications of the former USBOM evaluating 
    noise controls for various types of mining equipment.
        As noted previously, there are some instances where current noise 
    control technology still cannot reduce sound levels to within a 
    TWA8 of 90 dBA and where quieter replacement equipment may not be 
    feasible. An example of this is a pneumatic jackleg drill used in 
    hardrock mining. MSHA's data on equipment producing high levels of 
    noise are discussed in part III (see the discussion of a possible dose 
    ceiling in proposed Sec. 62.120(e)).
    Economic Feasibility of Engineering Controls
        The data from MSHA's dual-threshold survey, presented in Tables II-
    11 and II-12 in part II of this preamble, indicate that even with the 
    proposed new threshold level (80 dBA), almost three-quarters of the 
    metal and nonmetal samples, and almost two-thirds of the coal samples, 
    already are below the PEL. No additional controls would be required in 
    these cases.
        The Agency has determined that the incremental costs of the 
    requirements for engineering controls would be $3.5 million a year for 
    ten years, of which $2.2 million is allocable to the coal sector and 
    $1.3 million to the metal and nonmetal sector. (The additional costs to 
    the metal and nonmetal sector reflect in part the proposed lowering of 
    the threshold, which will result in the measurement of more 
    overexposures than at present.)
        As described in more detail in the Agency's preliminary RIA, to 
    calculate the costs for engineering controls, MSHA evaluated various 
    engineering controls and their related costs.
        In determining which engineering controls the metal and nonmetal 
    industry will have to use under the proposed rule, MSHA considered the 
    engineering controls that are used under the current rule. MSHA 
    believes that metal and nonmetal mine operators may generally have 
    exhausted the least costly engineering controls to comply with the 
    current rule for some job groups. Compliance with the proposed rule for 
    these job groups would require
    
    [[Page 66455]]
    
    that the mine operator use more expensive controls--specifically, 
    retrofitting equipment--or purchase new equipment. For other job 
    groups, however, mine operators may have used only those controls 
    necessary to comply with the PEL and the less costly controls may still 
    be available. To determine the cost of engineering controls, MSHA 
    looked at the average cost of such engineering controls.
        For the coal industry, HPDs have generally been substituted for 
    engineering and administrative controls, so the industry has not 
    exhausted the use of relatively inexpensive controls which have been 
    demonstrated to be capable of bringing about significant reductions of 
    sound levels. Even though the average cost of such controls would be 
    less than for the metal and nonmetal industry, the change in approach 
    would require controls be used much more often than at present. This is 
    why the industry would experience a relatively higher expense for 
    engineering controls.
        MSHA believes the requirements for engineering and administrative 
    controls clearly meet the feasibility requirements of the law. Based on 
    the comments received in response to its ANPRM and discussed below, 
    MSHA believes some in the industry may misunderstand the nature of the 
    engineering controls required. In many cases, inexpensive controls may 
    effectively eliminate overexposures.
    
    Comments on Feasibility of Engineering and Administrative Controls
    
        MSHA received numerous comments indicating that engineering 
    controls were not feasible to reduce a miner's noise exposure to within 
    the PEL for many types of mining equipment. Several commenters stated 
    that engineering controls are most effective when they are designed 
    into equipment versus applied by retrofitting. Other commenters stated 
    that retrofit noise controls are often not as durable or effective as 
    controls installed by the equipment manufacturer. One commenter 
    suggested that MSHA establish approval and certification procedures for 
    equipment noise emissions, similar to those established in part 18 for 
    permissible equipment used in gassy mines.
        In response to the commenters who indicated that engineering 
    controls were not feasible for many types of mining equipment, MSHA 
    would point out that significant progress has been made in developing 
    quieter mining equipment since the mid-1970's when MSHA's existing 
    noise standards were promulgated. Currently, almost all pneumatic drill 
    manufacturers offer exhaust mufflers where few were available in the 
    early 1970's. Similarly, almost all manufacturers of mobile surface 
    equipment offer environmental and/or acoustically treated cabs. Some 
    manufacturers also offer acoustically treated cabs for underground 
    mining equipment, such as jumbo drills and scoop trams. As noted, the 
    availability of feasible engineering noise controls is discussed in 
    greater detail in the section of the preamble on Engineering Noise 
    Controls for Mining Equipment.
        MSHA does not agree with the commenter who suggested that MSHA 
    establish approval and certification for equipment noise emissions 
    similar to part 18. Such a process could be more costly and limit a 
    mine operator's flexibility in implementing noise control procedures.
        The most cited disadvantage of engineering controls is cost. In 
    particular, some commenters are concerned that they would be required 
    to install controls that would not, by themselves, be adequate to 
    attain compliance. If this occurs, the proposal would also require that 
    administrative controls be used to reduce exposure to the PEL; 
    moreover, if a combination of controls does not reduce exposures to the 
    PEL, hearing protectors must be worn and the affected miners enrolled 
    in an HCP. These commenters believe that in such cases, costs to 
    install engineering controls are wasted since they still may have to 
    resort to these additional controls. More significantly, mine operators 
    are concerned that requiring engineering controls will usually require 
    the purchase of new equipment.
        The first concern is misplaced. Controlling noise requires the 
    hierarchy of requirements proposed by Sec. 62.120(c). A mine operator 
    has a choice as to what mix of engineering and administrative controls 
    to use as long as together they reduce noise exposures to the PEL or as 
    close thereto as feasible. Hearing protectors and enrollment in a 
    hearing conservation program are helpful when nothing more can feasibly 
    be done to reduce noise exposure, but they are not a substitute.
        MSHA generally agrees with the commenters who stated that 
    engineering controls are most effective when factory installed. The 
    Agency would encourage mine operators to purchase mining machinery 
    equipped with appropriate noise controls offered by the original 
    equipment manufacturer rather than retrofitting noise controls. Almost 
    every piece of mining equipment currently manufactured has optional 
    noise control packages. Based on comments and MSHA's experience in 
    noise control, the Agency has concluded that engineering controls 
    designed and installed by the manufacturer for a particular unit will 
    generally be more effective and durable than a retrofit control of 
    similar design. Additionally, the cost of such controls may in some 
    cases be substantially higher if it is purchased from the equipment 
    manufacturer on a retrofit basis, rather than at the time the unit was 
    originally built.
        At the same time, as discussed in part III, MSHA has determined 
    that some retrofit controls may be as effective as controls offered by 
    equipment manufacturers. Examples of engineering controls which are 
    routinely retrofitted onto existing mining equipment include: 
    environmental cabs; control booths; sound barriers and baffles; exhaust 
    mufflers; and the application of acoustical materials to equipment 
    firewalls and the inside walls of cabs and control booths. Moreover, 
    many successful retrofit noise controls (e.g., cabs, barrier shields, 
    and drill exhaust mufflers) were developed by operators using materials 
    readily available. Often the miners who use the equipment offer 
    valuable suggestions on improving the design and effectiveness of these 
    controls. Some of the controls developed by the mine operators have 
    been adopted by manufacturers for use on both existing and new 
    equipment. MSHA has determined that allowing the mine operator to 
    develop controls provides the mine operator with maximum flexibility in 
    complying with the standard thereby eliminating the need in those cases 
    to purchase manufacturer installed controls.
    Infeasibility of PEL at TWA8 of 85 dBA
        MSHA seriously considered lowering the PEL to a TWA8 of 85 dBA 
    because of its conclusion that there is a significant risk of material 
    impairment from noise exposures at or above this level. The Agency has 
    tentatively concluded, however, that it may not be feasible at this 
    time for the mining industry to reduce noise to that level.
        Exposure data collected by MSHA indicate that with a PEL at a 
    TWA8 of 85 dBA and an 80 dBA threshold, over two-thirds of the 
    mine operators in the metal and nonmetal industry, and over three-
    quarters of the mine operators in the coal industry, would need to use 
    engineering and administrative controls to reduce current exposures. 
    (See Tables II-11 and II-12 in part II.)
        Moreover, the engineering controls needed to reduce those exposures 
    would be more expensive, because they would have to reduce the 
    exposures further than with a PEL set at a TWA8 of 90 dBA. 
    Accordingly, the Agency
    
    [[Page 66456]]
    
    does not believe it can demonstrate that a reasonable probability 
    exists that the typical mine operator will currently be able to develop 
    and install controls that will meet such a standard.
        It is true that the proposed standard only requires that individual 
    mine operators use those controls which are feasible for that mine 
    operator. The feasibility requirement under the statute, however, is 
    that the Agency make a reasonable prediction, based on the ``best 
    available evidence,'' as to whether an industry can generally comply 
    with a standard within an allotted period of time. The Agency must show 
    that a reasonable probability exists that the typical mine operator 
    will be able to develop and install controls that will meet the 
    standard. Accordingly, MSHA believes that if most mine operators are 
    unlikely to be able to use engineering and administrative controls to 
    bring noise levels to a TWA8 of 85 dBA, the standard is not 
    feasible for the industry as a whole.
    Infeasibility of Exchange Rate of 3-dB
        The exchange rate is a measure of how quickly the dose of noise 
    doubles. Accordingly, the measure is the rate determining how much a 
    miner's exposure must be limited to compensate for increasing dose. For 
    example, at a 5-dB exchange rate, the exposure permitted at a sound 
    level of 90 dBA is half that permitted at a sound level of 85 dBA; a 
    miner gets the same noise dose in 4 hours at 90 dBA as at 8 hours at 85 
    dBA.
        The Agency gave serious consideration to changing the exchange rate 
    from 5-dB to 3-dB, and is specifically seeking comment on this 
    important matter. There is a consensus in the recent literature that 
    noise dose actually doubles more quickly than measured by the 5-dB 
    rate, and in particular consensus for an exchange rate of 3-dB. 
    Moreover, MSHA has concluded that the type of noise exposure in the 
    mining environment tends to warrant an exchange rate that does not 
    assume significant time for hearing to recover from high sound levels--
    the current exchange rate incorporates such an assumption. A full 
    discussion of the scientific merits of various exchange rates, and of 
    the rates used by various regulatory authorities, can be found in part 
    III of the Preamble (as part of the discussion of proposed 
    Sec. 62.120(a), dose determination).
        Nevertheless, the Agency is proposing to retain the existing 5-dB 
    exchange rate because of feasibility considerations. Changing to a 3-dB 
    rate from a 5-dB rate would significantly reduce the amount of time 
    that miners could be exposed to higher sound levels without exceeding 
    the permissible exposure limit. For example, MSHA estimates that the 
    percentage of miners whose exposure would be in violation of a PEL set 
    at a TWA8 of 90 dBA would about double if a 3-dB exchange rate is 
    used. (See Table III-3 in the exchange rate discussion in part III. The 
    table also indicates what would happen if the PEL were set at a 
    TWA8 of 85 dBA). This means mine operators would have to utilize 
    controls to reduce exposures to the PEL more frequently. Moreover, more 
    expensive controls would often be required, since the need to reduce 
    exposures more to get them down to the PEL.
        The feasibility requirement under the statute is that the Agency 
    make a reasonable prediction, based on the ``best available evidence,'' 
    as to whether an industry can generally comply with a standard within 
    an allotted period of time. The Agency must show that a reasonable 
    probability exists that the typical mine operator will be able to 
    develop and install controls that will meet the standard. The exposure 
    data noted indicate it may be difficult for MSHA to make such a 
    showing.
        Furthermore, if a 3-dB exchange rate is used, it is extremely 
    difficult to reduce the noise exposures to below the PEL with currently 
    available engineering or administrative noise controls or a combination 
    thereof.
        Accordingly, MSHA has tentatively concluded that moving the 
    industry to a 3-dB exchange rate may not be feasible at this time.
    
    Conclusion
    
        Based on the information before it, the Agency has tentatively 
    concluded that the proposed rule meets the statutory requirements for 
    feasibility, and that it may not be feasible for the mining industry, 
    as a whole, at this time, to require a more protective regimen.
        The Agency is particularly interested in receiving additional data 
    that would be relevant in making final determinations on the points 
    discussed above.
    
    V. References
    
    ``A Code of Practice for Noise Control in the Workplace,'' Occupational 
    Health, Safety and Welfare Commission on Western Australia, August 
    1991.
    Abel, Sharon M. and Caroline A. Haythornthwaite, ``The Progression of 
    Noise-Induced Hearing Loss,'' Journal of Otolaryngology, 13:1-36, 1984.
    Abel, Sharon M., ``Noise-Induced Hearing Loss and Hearing Protective 
    Devices,'' Canadian Journal of Public Health, 77(1):104-107, May-June 
    1986.
    Abel, Sharon M. and Diane Rokas, ``The Effect of Wearing Time on 
    Hearing Protector Attenuation,'' Journal of Otolaryngology, 15(5):293-
    297, 1986.
    Acoustical Society of America, ``American National Standard Method for 
    the Measurement of Real-Ear Protection of Hearing Protectors and 
    Physical Attenuation of Ear Muffs,'' ANSI S3.19-1974 (R-1979), (ASA 1-
    1975), American Institute of Physics, New York, NY, pp. 1-9, August 14, 
    1974.
    Acoustical Society of America, ``American National Standard Methods for 
    Manual Pure-Tone Threshold Audiometry,'' ANSI S3.21-1978 (ASA 19-1978), 
    American Institute of Physics, New York, NY, pp. 1-7, June 7, 1978.
    Acoustical Society of America, ``American National Standard 
    Specification for Sound Level Meters,'' ANSI S1.4-1983 (ASA 47-1983), 
    American Institute of Physics, New York, NY, pp. 1-18, February 17, 
    1983.
    Acoustical Society of America, ``American National Standard Methods for 
    Measurement of Impulse Noise,'' ANSI S12.7-1986 (ASA 62-1986), American 
    Institute of Physics, New York, NY, pp. 1-9, February 20, 1986.
    Acoustical Society of America, ``American National Standard Evaluating 
    The Effectiveness of Hearing Conservation Programs,'' ANSI S12.13-1991 
    (ASA 72-1991), American National Standards Institute, Inc., New York, 
    NY, pp. 1-56, (Draft date January 12, 1990).
    Acoustical Society of America, ``American National Standard 
    Specification for Personal Noise Dosimeters,'' ANSI S1.25-1991 (ASA 98-
    1991), American Institute of Physics, New York, NY, pp. 1-10, October 
    24, 1991.
    Acoustical Society of America, ``American National Standard Maximum 
    Permissible Ambient Noise Levels for Audiometric Test Rooms,'' ANSI 
    S3.1-1991 (ASA 99-1991), American Institute of Physics, New York, NY, 
    pp. 1-14, December 24, 1991.
    Acoustical Society of America, ``American National Standard 
    Specification for Audiometers,'' ANSI S3.6-1996, American National 
    Standards Institute, Inc., New York NY, pp. 1-33, January 12, 1996.
    
    [[Page 66457]]
    
    Adera, T. et al., ``Assessment of the Proposed Draft American National 
    Standard Method for Evaluating the Effectiveness of Hearing 
    Conservation Programs,'' Journal Of Occupational Medicine, 35(6):568-
    573, June 1993.
    Aljoe, William W. et al., U.S. Bureau of Mines, ``The Bureau of Mines 
    Noise-Control Research Program--A 10-Year Review,'' Bureau of Mines 
    Information Circular IC 9004, pp. 1-85, 1985.
    Ambasankaran, M. et al., ``Occupational Noise Exposure and Hearing 
    Levels,'' American Industrial Hygiene Association Journal,  42:551-555, 
    July 1981.
    American Academy of Ophthalmology and Otolaryngology, Committee on 
    Conservation of Hearing, ``Guide for the Evaluation of Hearing 
    Impairment,'' Transactions of the American Academy of Ophthalmology and 
    Otolaryngology, 63:236-238, March-April 1959.
    American Academy of Otolaryngology, Committee on Hearing and 
    Equilibrium, and the American Council of Otolaryngology Committee on 
    the Medical Aspects of Noise, ``Guide for the Evaluation of Hearing 
    Handicap,'' Journal of the American Medical Association, 241(19):2055-
    2059, May 11, 1979.
    American Conference of Governmental Industrial Hygienists Inc. (ACGIH), 
    ``Documentation of the Threshold Limit Values and Biological Exposure 
    Indices,'' (5th Ed.) pp. 662-666, 1986.
    American Conference of Governmental Industrial Hygienists Inc. (ACGIH), 
    ``Threshold Limit Values for Chemical Substances and Physical Agents 
    and Biological Exposures Indices,'' American Conference of Governmental 
    Industrial Hygienists, pp. 104-109, 1993-1994.
    American Conference of Governmental Industrial Hygienists Inc. (ACGIH), 
    ``Threshold Limit Values for Chemical Substances and Physical Agents 
    and Biological Exposures Indices,'' American Conference of Governmental 
    Industrial Hygienists, pp. 104-105, 1994-1995.
    American Industrial Hygiene Association (AIHA), Letter to EPA; ``Revise 
    Hearing Protection Device Labeling,'' Federal News, The Synergist, 
    November 1995.
    American Iron and Steel Institute v. OSHA, 577 F. 2d 825 (3d Circuit 
    1978).
    American Textile Manufacturers Institute, Inc., v. Donovan, Secretary 
    of Labor, et al., 452 U.S. 490, 508-509 (1981).
    Barham, T.D. et al., ``Improving the Protection Afforded by Earmuffs to 
    Employees Who Are Exposed to Noise,'' Noise Control Engineering 
    Journal, 33(2):67-76, September-October 1989.
    Bartholomae, Roy C. and Robert P. Parker, ``Mining Machinery Noise 
    Control Guidelines, 1983,'' U.S. Department of the Interior, U.S. 
    Bureau of Mines Handbook, 1983.
    Bartsch, R. et al., ``High-Frequency Audiometry in the Evaluation of 
    Critical Noise Intensity,'' International Archives of Occupational and 
    Environmental Health, 61(5):347-351, March 1989.
    Baughn, W.L., ``Relation Between Daily Noise Exposure and Hearing Loss 
    Based on the Evaluation of 6,835 Industrial Noise Exposure Cases,'' 
    AMRL-TR-73-53 (AD 767 204), Aerospace Medical Research Laboratory, 
    Wright-Patterson Air Force Base, OH, p. 28, June 1973.
    Behar, Alberto, ``Field Evaluation of Hearing Protectors,'' Noise 
    Control Engineering Journal, 24(1):13-18, January-February 1985.
    Berger, Elliott H., ``The Effects of Hearing Protectors on Auditory 
    Communications,'' E*A*R*LOG 3, E*A*R Division, Cabot Corporation, 
    Indianapolis, IN, 1980.
    Berger, E.H., ``Hearing Protector Performance: How They Work--and--What 
    Goes Wrong in the Real World,'' EARLOG 5, E*A*R Division, Cabot 
    Corporation, Indianapolis, IN, 1980.
    Berger, E.H., ``Extra-Auditory Benefits of a Hearing Conservation 
    Program,'' EARLOG 6, E*A*R Division, Cabot Corporation, Indianapolis, 
    IN, 1981.
    Berger, E.H., ``Responses to Questions and Complaints Regarding Hearing 
    and Hearing Protection (Part I),'' EARLOG 8, E*A*R Division, Cabot 
    Corporation, Indianapolis, IN, 1981.
    Berger, E.H., ``Attenuation of Earplugs Worn in Combination With 
    Earmuffs,'' EARLOG 13, E*A*R Division, Cabot Corporation, Indianapolis, 
    IN, 1984.
    Berger, E.H., ``Ear Infection and the Use of Hearing Protection,'' 
    EARLOG 17, E*A*R Division, Cabot Corporation, Indianapolis, IN, 1985.
    Berger, E.H., ``Tips for Fitting Hearing Protectors,'' EARLOG 19, E*A*R 
    Division, Cabot Corporation, Indianapolis, IN, 1988.
    Berger, E.H., et al., ``Presumed Noise-Induced Permanent Threshold 
    Shift Resulting from Exposure to an A-weighted Leq of 89 dB,'' 
    Journal of the Acoustical Society of America, 64(1):192-197, July 1978.
    Berger, E.H., ``Details of Real World Hearing Protector Performance as 
    Measured in the Laboratory,'' Noise-Con 81 Raleigh, North Carolina pp. 
    147-152, June 1981.
    Berger, E.H., ``Using the NRR to Estimate the Real World Performance of 
    Hearing Protectors,'' Sound and Vibration, 17(1):18, January 1983.
    Berger, E.H., ``Hearing Protection Devices,'' Ch. 10 in Noise & Hearing 
    Conservation Manual (4th Edition), ed. Elliott H. Berger et al., 
    American Industrial Hygiene Association, Akron, OH, 1986, pp. 319-381.
    Berger, E.H., ``Development of a Laboratory Procedure for the 
    Estimation of the Field Performance of Hearing Protectors,'' 
    Proceedings 1992 Hearing Conservation Conference, UKY BU156, University 
    of Kentucky and NIOSH, Lexington, KY, p. 44, April 1992.
    Bertrand, Robert A. and Jean Zeidan, ``Retrospective Field Evaluation 
    Of HPD Based On Evolution Of Hearing,'' Proceedings of the 6th 
    International Congress, Nice, France, pp. 21-24, July 1993.
    Bies, David A. and Colin H. Hansen, ``An Alternative Mathematical 
    Description of the Relationship between Noise Exposure and Hearing 
    Loss,'' Journal of the Acoustical Society of America, 88(6):2743-2754, 
    December 1990.
    British Occupational Hygiene Society Committee on Hygiene Standards, 
    ``Hygiene Standard for Impulse Noise,'' Annals of Occupational Hygiene, 
    19:179-191, 1976.
    Bruhl, P. and A. Ivarsson, ``Noise-exposed Male Sheet-metal Workers 
    Using Hearing Protectors,'' A Longitudinal Study of Hearing Threshold 
    Shifts Covering 15 Years, Scandinavian Audiology, 23:123-128, 1994.
    Bruhl, P., et al., ``Noise-induced Hearing Loss in an Automobile Sheet-
    metal Pressing Plant,'' A Retrospective Investigation Covering 25 
    Years, Scandinavian Audiology, 23:83-91, 1994.
    Burks, J.A. and R.C. Bartholomae, ``Noise Reduction Potential of a 
    Variable Speed Driven Coal Mining Conveyor,'' Proceedings of the 
    Symposium held at the SME Annual Meeting, Phoenix, Arizona, February 
    24-27, 1992.
    Burns, W. and D.W. Robinson, ``Hearing and Noise in Industry,'' 
    Department of Health and Social Security, London: Her Majesty's 
    Stationary Office, 1970.
    
    [[Page 66458]]
    
    Canadian Standards Association, ``Procedures for the Measurement of 
    Occupational Noise Exposure,'' CAN/CAS-Z107.56-M86, December 1986.
    Carter, N.L. and G. Upfold, ``Comparison of Earphone and Sound Field 
    Methods for Estimating Noise Attenuation of Foam Earplugs,'' National 
    Acoustic Laboratories, pp. 307-312, June 1993.
    Casali, John G. and Siu T. Lam, ``Effects of User Instructions on 
    Earmuff/Earcap Sound Attenuation,'' Sound and Vibration, pp. 26-27, May 
    1986.
    Casali, John G. and James F. Grenell, ``An Exploratory Study of 
    Moderate Physical Activity and Selected Design Attribute Effects on 
    Earmuff Attenuation,'' American Industrial Hygiene Association Journal, 
    50:480-485, September 1989.
    Casali, John G. and Min-Young Park, ``A Regression-Based Methodology 
    for Efficient Prediction of Broadband Attenuation of Hearing 
    Protectors,'' Noise Control Engineering Journal, 38(3):97-108, May-June 
    1992.
    Chiusano, Stephen V., et al., ``An Occupational Noise Exposure 
    Assessment for Headset-Wearing Communications Workers,'' Applied 
    Occupational Environmental Hygiene, 10(5):476-481, May 1995.
    Chung, David Y. and Richard Hardie, ``The Performance of Circumaural 
    Hearing Protectors by Dosimetry,'' Journal of Occupational Medicine, 
    25(9):679-682, September 1983.
    Cluff, Gordon L., ``Noise Dose from Impulse and Continuous Noise,'' 
    Sound and Vibration, pp. 18-21, March 1982.
    Cluff, Gordon L., ``Is the Five dB Doubling Rule an Accurate Basis for 
    Noise Limits?,'' Occupational Health & Safety, pp. 45-49, July-August 
    1984.
    Cluff, Gordon L., ``Insert-Type Hearing Protector Stability as a 
    Function of Controlled Jaw Movement,'' American Industrial Hygiene 
    Association Journal, 50:147-151, March 1989.
    Coleman, G.J., et al., ``Communications in Noisy Environments,'' Final 
    Report on CEC Contract 7206/00/8/09, Institute of Occupational 
    Medicine, pp. 1-168, June 1984.
    Coles, R. Ross A., et al., ``Criteria for Assessing Hearing Damage Risk 
    from Impulse-Noise Exposure,'' U.S. Army Technical Memorandum 13-67, 
    AMCMS Code 5011.11.84100, Human Engineering Laboratory, Aberdeen 
    Proving Ground, MD, August 1967.
    Committee on Hearing, Bioacoustics, and Biomechanics (CHABA), 
    Commission on Behavioral and Social Sciences and Education, National 
    Research Council, ``Hazardous Exposure to Steady- State and 
    Intermittent Noise.'' National Academy Press, Washington, D.C., 1993.
    Council Directive of May 12, 1986, ``On The Protection Of Workers From 
    The Risks Related To Exposure To Noise At Work,'' Official Journal of 
    the European Communities, (86/188/EEC), pp. 35-41, May 12, 1986.
    Council of the South African Bureau of Standards, South African 
    Standard, Code of Practice for ``The Measurement and Assessment of 
    Occupational Noise of Hearing Conservation Purposes,'' SABS 083-1983 
    (as amended 1986 and 1989) 1989.
    Crawford, D.R. and R.J. Nozza, ``Field Performance Evaluation of 
    Wearer-Molded Ear Inserts,'' Presented at the American Industrial 
    Hygiene Association Conference, Portland, Oregon, May 29, 1981.
    Dear, Terrence A., ``Noise Criteria Regarding Risk and Prevention of 
    Hearing Injury in Industry,'' Ch. 18 in Occupational Hearing Loss, ed. 
    Robert Thayer Sataloff and Joseph Sataloff, Marcel Dekker, Inc., New 
    York, NY, pp. 485-507, 1987.
    Driscoll, Dennis P., and Jeffrey C. Morrill, ``A Position Paper on a 
    Recommended Criterion for Recording Occupational Hearing Loss on the 
    OSHA Form 200,'' American Industrial Hygiene Association Journal, pp. 
    714-716, November 1987.
    Durkt, George and Leonard C. Marraccini, ``Hearing Protector 
    Effectiveness in Mines: A Retrospective Study,'' Annals of the American 
    Conference of Governmental Industrial Hygienists, 14:565-573, 1986.
    Durkt, George, Jr., ``Field Evaluation of Hearing Protective Devices at 
    Surface Mining Environments,'' MSHA Informational Report IR 1213, pp. 
    1-31, 1993.
    Eden, David, ``Australian Mining Industry Experience In Hearing 
    Conservation,'' Noise & Man '93, Noise as a Public Health Problem, 
    Proceedings of the 6th International Congress, Nice, France, pp. 47-50, 
    July 1993.
    Embleton, Tony F.W., Report by the International Institute of Noise 
    Control Engineering Working Party on ``Upper Limits on Noise in the 
    Workplace,'' Noise/News International, pp. 230-237, December 1994.
    Evans, W.A. and Hui Yat Ming, ``Industrial Noise-Induced Hearing Loss 
    in Hong Kong--A Comparative Study,'' Annals of Occupational Hygiene, 
    25(1):63-80, 1982.
    Fechter, Laurence D., ``Combined Effects of Noise and Chemicals,'' 
    Occupational Medicine, 10(3):609-621, July-September 1995.
    Fodor, William J. and Arthur Oleinick, ``Workers' Compensation for 
    Occupational Noise-Induced Hearing Loss: A Review of Science and the 
    Law, and Proposed Reforms,'' Saint Louis University Law Journal, 
    30:719-729, 1986.
    Franks, John R., et al., ``Analysis of a Hearing Conservation Program 
    Data Base: Factors Other Than Workplace Noise,'' Ear and Hearing 
    10(5):273-280, 1989.
    Giardino, Dennis A. and George Durkt, ``Evaluation of Muff-Type Hearing 
    Protectors as Used in the Mining Industry,'' U.S. Department of Labor, 
    Informational Report IR 1222, pp. 1-21, June 1994.
    Giardino, Dennis A. and George Durkt, ``Evaluation of Muff-Type Hearing 
    Protectors as Used in the Mining Industry,'' American Industrial 
    Hygiene Association Journal, 57:264-271, 1996.
    Goff, Richard J. and William J. Blank, ``A Field Evaluation of Muff-
    Type Hearing Protection Devices,'' Sound and Vibration, 18:16-22, 
    October 1984.
    Goff, Richard J., et al., ``Muff-Type Hearing Protectors--How Well Do 
    They Perform in the Field,'' Annals of the American Conference of 
    Governmental Industrial Hygienists, 14:545-555, 1986.
    Gosztonyi, R.E., Jr., ``The Effectiveness of Hearing Protective 
    Devices,'' Journal of Occupational Medicine, 17(9):569-580, September 
    1975.
    Green, William W., et al., ``Effectiveness of Insert-Type Hearing 
    Protectors (Earplugs) in the Workplace,'' Proceedings 1989 Industrial 
    Hearing Conservation Conference, UKY BU149, University of Kentucky and 
    NIOSH, Lexington, KY, p. 30, April 1989.
    Guidelines for the Conduct of an Occupational Hearing Conservation 
    Program,'' Journal of Occupational Medicine, 29:981-982, December 1987.
    Guidelines for the Implementation and Control of a Hearing Conservation 
    Programme in the South African Mining Industry Chamber of Mines of 
    South Africa, 1988.
    
    [[Page 66459]]
    
    Hempstock, T.I. and E. Hill, ``The Attenuations of Some Hearing 
    Protectors As Used In The Workplace,'' American Occupational Hygiene 
    Association Journal, 34(5):453-470, 1990.
    Henderson, Donald, ``Acoustic Parameters of Hazardous Noise 
    Exposures,'' Noise and Hearing Loss, NIH Consensus Development 
    Conference, pp. 43-45, January 22-24, 1990.
    Hodge, David C. and G. Richard Price, ``Hearing Damage Risk Criteria,'' 
    Ch. 6 in Noise and Audiology, ed. David M. Lipscomb, University Park 
    Press, Baltimore, MD, 1978, pp. 167-191.
    Holmgren, G., et al., ``Noise and Hearing of a Population of Forest 
    Workers,'' pp. 35-42, 1971.
    Hopkinson, Norma T., ``Prevalence of Middle Ear Disorders in Coal 
    Miners,'' U.S. Department of Health and Human Services DHHS (NIOSH) 
    Publication No. 81-101, June 1981.
    Industrial Union Dep't., AFL-CIO v. Hodgson, 499 F. 2d 467 (D.C. 
    Circuit 1974).
    Institut National De Recherche Et De Securite, ``Etude Des Risques 
    Auditifs Auxquels Sont Soumis Les Salaries Agricoles En Exploitstions 
    Forestieres Et En Scieries,'' May 1978.
    International Organization for Standardization, ``Acoustics--
    Determination of Occupational Noise Exposure and Estimation of Noise-
    Induced Hearing Impairment,'' ISO 1999-1990.
    Jansen, Gerd, ``Physiological Effects of Noise,'' Ch. 25 in Handbook of 
    Acoustical Measurements and Noise Control, (3rd edition), ed. Cyril M. 
    Harris, McGraw-Hill, Inc., pp. 1-25, 1991.
    Johansson, B., et al., ``Evaluation of The Hearing Damage Risk from 
    Intermittent Noise According to the ISO Recommendation,'' Proceedings 
    of the International Congress on Noise as a Public Health Problem, pp. 
    201-210, May 13-18, 1973.
    Johnson, Daniel L. and Thomas R. Schori, ``How Safe is 115 dB for 15 
    Minutes?'' Journal of the Acoustical Society of America, 61(1):S76, 
    Spring 1977.
    Kasden, Stephen D. and Anthony D'Aniello, ``Changes in Attenuation of 
    Hearing Protectors During Use,'' Noisexpo New York, NY, March 29-31, 
    1976.
    Kasden, S.D. and A. D'Aniello, ``Changes in Attenuation of Hearing 
    Protectors During Use,'' Audiology and Hearing Education, pp. 18-19, 
    August-September 1978.
    Kogut, Jon and Richard J. Goff, ``Analysis of Noise Reduction with 
    Earmuff Hearing Protectors under Field Conditions,'' Informational 
    Report IR 1221, pp. 1-31, 1994.
    Krutt, M.A. and Marvin Mazor, ``Attenuation Changes During the Use of 
    Mineral Down and Polymer Foam Insert-type Hearing Protectors,'' 
    Audiology and Hearing Education, pp. 13-14, Winter 1980-1981.
    Kryter, K.D. et al., ``Hazardous Exposure to Intermittent and Steady-
    State Noise,'' Journal of the Acoustical Society of America, 39(3):451-
    464, 1966.
    Kryter, K.D., ``Damage Risk from Exposure to Noise,'' Ch. Five in The 
    Effects of Noise on Man, Academic Press, Inc., New York, NY, pp. 139-
    205, 1970.
    Kryter, K.D., ``Physiological, Psychological, and Social Effects of 
    Noise,'' National Aeronautics and Space Administration (NASA), NASA 
    Reference Publication 1115, N84-29465, pp. 175-341, 1984.
    Lancaster, G.K., ``Personal Noise Exposure,'' Colliery Guardian, 
    234(5):213-216, March 1986.
    Lempert, Barry L. and T.L. Henderson, ``Occupational Noise and Hearing 
    1968-1972,'' HEW Publication No. (NIOSH) 74-116, U.S. Department of 
    Health, Education, and Welfare, U.S. Government Printing Office, 
    Washington, DC, pp. 1-51, 1973.
    Lempert, Barry L. and Richard G. Edwards, ``Field Investigations of 
    Noise Reduction Afforded by Insert-Type Hearing Protectors,'' American 
    Industrial Hygiene Association Journal, 441(12):894-902, December 1983.
    Lercher, Peter et al., ``Work Noise Annoyance and Blood Pressure: 
    Combined effects with stressful working conditions,'' International 
    Archives of Occupational Environmental Health, 65:23-28, 1993.
    Lescouflair, G. et al., ``Hearing Loss Among Miners Claiming 
    Compensation,'' Archives of Otolaryngology, 106:602-609, October 1980.
    Macrae, J.H., ``Presbycusis and Noise-Induced Permanent Threshold 
    Shift,'' Journal of the Acoustical Society of America, 90(5):2513-2516, 
    November 1991.
    Maraccini, Leonard C., et al., ``Summary of Noise Control For Mining 
    Machinery,'' Mine Safety and Health Administration, U.S. Department of 
    Labor, pp. 1-183, 1986.
    Maraccini, Leonard C., ``Comparison of Hearing Protector Rating Methods 
    and Recommendations for Use in the Mining Industry,'' Informational 
    Report IR 1176, Mine Safety and Health Administration, U.S. Department 
    of Labor, pp. 1-28, 1987.
    Martin, R.H. et al., ``Occupational Hearing Loss Between 85 and 90 
    dBA,'' Journal of Occupational Medicine, 17(1):13-18, January 1975.
    McRobert, H. and W.D. Ward, ``Damage-Risk Criteria: The Trading 
    Relation Between Intensity and the Number of Nonreverberant Impulses,'' 
    Journal of the Acoustical Society of America, 53(5):1297-1300, 1973.
    Melamed, Samuel and Shelly Bruhis, ``The Effects of Chronic Industrial 
    Noise Exposure on Urinary Cortisol, Fatigue, and Irritability,'' 
    Journal of Occupational and Environmental Medicine, 38(3):252-256, 
    1996.
    Melnick, William et al., Occupational Noise--Volume I, The Ohio State 
    University Research Foundation Final Report, RF Project 761779/712233, 
    for the U.S. Department of Labor Contract No. J-9-E-9-0166, pp. 1-290, 
    December 1980.
    Melnick, William et al., Occupational Noise--Volume II, The Ohio State 
    University Research Foundation Final Report, RF Project 761779/712233, 
    for the U.S. Department of Labor Contract No. J-9-E-9-0166, pp. 1-200, 
    December 1980.
    Melnick, William, ``Damage Risk Criteria,'' Ch. 12 in Forensic 
    Audiology, ed. M.B. Kramer and J.M. Armbruster, University Park Press, 
    Baltimore, MD, pp. 223-258, 1982.
    Merry, Carol J. et al., ``The Effect of Fitting Procedure on Hearing 
    Protector Attenuation,'' Ear and Hearing, 13(1):11-18, 1992.
    Michael, Paul L., ``Industrial Noise and Conservation of Hearing,'' Ch. 
    23 in Patty's Industrial Hygiene and Toxicology, ed., George D. Clayton 
    and Florence E. Clayton, John Wiley & Sons, Inc., pp. 937-1039, 1991.
    Miller, Maurice H., ed., Council for Accreditation in Occupational 
    Hearing Conservation Manual (2nd Edition) Association Management 
    Corporation, Springfield, NJ, pp. 79-143, 1985.
    Mines Accident Prevention Association Ontario, ``An Analysis of 
    Occupational Diseases In The Ontario Mining Industry 1985-1989,'' 
    Report No. 9102, February 1991.
    
    [[Page 66460]]
    
    Morata, Thais C., ``Study of the Effects of Simultaneous Exposure to 
    Noise and Carbon Disulfide on Workers' Hearing,'' Scandinavian 
    Audiology, 18:53-58, 1989.
    Morata, Thais C. et al., ``Effects of Occupational Exposure to Organic 
    Solvents and Noise on Hearing,'' Scandinavian Journal of Work 
    Environmental Health, 19(4):245-254, 1993.
    Morata, Thais C., et al., ``Auditory and vestibular functions after 
    Single or Combined Exposure to Toluene: A Review,'' Archives of 
    Toxicology,'' 69:431-443, 1995.
    Moretz, Sandy, ``Decibel Damage,'' Occupational Hazards, pp. 41-44, 
    September 1990.
    MSHA, Noise; Advance Notice of Proposed Rulemaking, December 4, 1989.
    MSHA, Program Policy Manual, Volume IV, PART 56/57, April 1, 1990, pp. 
    41-41a.
    National Hearing Conservation Association, ``Comments to the Department 
    of Labor on OSHA's Proposed Rule on Noise Standards,'' March 1994.
    National Institutes of Health (NIH), National Consensus Statement, NIH 
    Consensus Development Conference, 8(1):3-24, January 22-24, 1990.
    Nilsson, R. et. al., ``Noise Exposure and Hearing Impairment in the 
    Shipbuilding Industry,'' Scandinavian Audiology, 6:59-68, 1977.
    NIOSH, ``Criteria for a Recommended Standard * * * Occupational 
    Exposure to Noise,'' HSM 73-11001, U.S. Department of Health, 
    Education, and Welfare, U.S. Government Printing Office, Washington, 
    D.C., pp. 1-142, 1972.
    NIOSH, ``List of Personal Hearing Protectors and Attenuation Data,'' 
    HEW Publication No. (NIOSH) 76-120, September 1975.
    NIOSH, ``Survey of Hearing Loss in the Coal Mining Industry,'' HEW 
    Publication No. (NIOSH) 76-172, June 1976.
    NIOSH, ``Health Hazard Evaluation Report (Firefighters Studies),'' HETA 
    81-059-1045, Newburgh Fire Department, Newburgh, NY, pp. 1-41, February 
    1982.
    NIOSH, ``A Proposed National Strategy for the Prevention of Noise- 
    Induced Hearing Loss,'' DHHS (NIOSH) Publication No. 89-135, pp. 1-13, 
    1988.
    NIOSH/Association of Schools of Public Health, ``Proposed National 
    Strategies for the Prevention of Leading Work-Related Diseases and 
    Injuries Part 2,'' pp. 51-63, 1988.
    NIOSH, ``Compendium of Hearing Protection Devices,'' Franks, John R. et 
    al., Cincinnati, Ohio, pp. 1-78, October 1994.
    NIOSH, Letter to James R. Petrie, from Richard Niemeier, ``Hierarchy of 
    Controls for MSHA's Noise Standard,'' pp. 1-3, December 16, 1994, and 
    cover letter to Andrea Hricko from Linda Rosenstock, August 14, 1996.
    NIOSH, Letter to James R. Petrie, from Linda Rosenstock, ``The 
    Development of the Noise Proposed Standard,'' pp. 1-29 NIOSH Building, 
    Washington, DC, March 13, 1995.
    NIOSH, Letter to James R. Petrie, from Richard Niemeier, ``State Worker 
    Compensation Data Relating to Occupational Noise-Induced Hearing Loss 
    in Miners,'' pp. 1-6, and ``A Survey of States' Workers' Compensation 
    Practices for Occupational Hearing Loss,'' pp. 2-8, NIOSH Building, 
    Cincinnati, Ohio, April 13, 1995.
    NIOSH, ``Analysis of Audiograms for a Large Cohort of Noise-Exposed 
    Miners'', John Franks, pp. 1-7, and cover letter to Davitt McAteer, 
    from Linda Rosenstock, August 6, 1996.
    National Occupational Health and Safety Commission, ``National Standard 
    for Occupational Noise,'' [NOHSC:1007(1993)], (Australia).
    National Occupational Health and Safety Commission, ``National Code of 
    Practice for Noise Management and Protection of Hearing at Work,'' 
    [NOHSC:2009(1993)], (Australia).
    Nixon, C.W. and E.H. Berger, ``Hearing Protection Devices,'' Ch. 21 in 
    Handbook of Acoustical Measurements and Noise Control (3rd edition) ed. 
    Cyril M. Harris, McGraw-Hill, Inc., pp. 1-24, 1991.
    Nixon, J.C. and A. Glorig, ``Noise-Induces Permanent Threshold Shift at 
    2000 cps and 4000 cps,'' Journal of the Acoustical Society of America, 
    33(7):904-908, July 1961.
    Noise Standard for Brazil June 1978.
    Occupational Safety and Health Administration (OSHA), Occupational 
    Noise Exposure Proposal, October 24, 1974 [39 FR 37773-37778].
    Office of Technology and Assessment, ``Preventing Illness and Injury in 
    the Workplace,'' Ch. 9. Hierarchy of Controls, OTA Publication No. OTA-
    H-256, Washington, D.C., pp. 175-185, April 1985.
    OSHA (OSHA), Form 200, June 4, 1991.
    OSHA, Hearing Conservation Amendment, January 16, 1981 [46 FR 4078-
    4179].
    OSHA, Hearing Conservation Amendment, March 8, 1983 [46 FR 9738-9784].
    OSHA, Occupational Noise Exposure, 29 CFR 1910.95.
    OSHA's Field Operations Manual, OSHA Instruction CPL 2.45A CH-12, pp. 
    IV-32-IV-34, September 21, 1987.
    Park, Min-Yong and John G. Casali, ``A Controlled Investigation of In-
    Field Attenuation Performance of Selected Insert, Earmuff, and Canal 
    Cap Hearing Protectors,'' Human Factors, 33:693-714, December 1991.
    Passchier-Vermeer, W., ``Noise-Induced Hearing Loss from Exposure To 
    Intermittent and Varying Noise,'' Proceedings of the International 
    Congress on Noise as a Public Health Problem, U.S. Environmental 
    Protection Agency, pp. 169-200, May 13-18, 1973.
    Passchier-Vermeer, W., ``Hearing Loss Due To Continuous Exposure To 
    Steady-State Broad-Band Noise,'' Acoustical Society of America, 
    56(5):1595-1593, November 1974.
    Pell, Sidney, ``An Evaluation of a Hearing Conservation Program,'' 
    American Industrial Hygiene Association Journal, 33:60-70, February 
    1972.
    Pell, Sidney ``An Evaluation of a Hearing Conservation Program--A Five 
    Year Longitudinal Study,'' American Industrial Hygiene Association 
    Journal, 34:82-91, February 1973.
    Pell, Sidney and Terrence A. Dear, ``Evaluation of a 20-Year Hearing 
    Conservation Program,'' Noise as a Public Health Problem, Vol. II, 
    Swedish Council for Building Research, Stockholm, Sweden, pp. 159-164, 
    1988.
    Pell, Sidney and Terrence A. Dear, ``Evaluation of a 20-Year Hearing 
    Conservation Program,'' Proceedings 1989 Industrial Hearing 
    Conservation Conference, UKY BU149, University of Kentucky and NIOSH, 
    Lexington, KY, pp. 47-50, April 1989.
    Pfeiffer, Bodo H., ``Real-World Effectiveness of Hearing Protection 
    Devices in German Industry,'' 1992 Hearing Conservation Conference, 
    University of Kentucky, pp. 21-24, April 1-4, 1992.
    Phoon, W.H. and H.S. Lee, ``Hearing Protection Plans Require Proper Ear 
    Plug Selection, Usage,'' Occupational Health and Safety, May 1993.
    
    [[Page 66461]]
    
    Plog, Barbara A. et al., ``Fundamentals of Industrial Hygiene,'' 4th 
    Edition, National Safety Council, p. 206, 1995.
    Prout, James H. et al., ``A Study of Roof Warning Signals and the Use 
    of Personal Hearing Protection in Underground Coal Mines,'' The 
    Pennsylvania State University, December 15, 1973, pp. 1-239.
    Regan, Donald E.: ``Real Ear Attenuation of Personal Ear Protective 
    Devices Worn in Industry.'' Ph.D. diss., Kent State University, 1975.
    Rink, Timothy L., ``Hearing Protection Works,'' Occupational Health and 
    Safety, October 1996, pp. 59-64.
    Rop, I. et al., ``Study of the Hearing Losses of Industrial Workers 
    with Occupational Noise Exposure, Using Statistical Methods for the 
    Analysis of Qualitative Data,'' Audiology, 18:181-196, 1979.
    Royster, Julia D. and Larry H. Royster, ``Hearing Protection Devices,'' 
    Ch. 6 in Key Topics In Hearing Conservation: Program Organization, 
    Hearing Protection, and Audiometric Data Base Analysis and Dealing With 
    and Preventing Compensation for Noise-Induced Hearing Loss, pp. 103-
    149, 1988.
    Royster, Julia D. and Larry H. Royster, ``Hearing Conservation 
    Programs,'' Practical Guidelines for Success, Lewis Publishers, Inc., 
    Chelsea, MI, p. 51, 1990.
    Royster, Julia D., ``Evaluation of Different Criteria for Significant 
    Threshold Shift in Occupational Hearing Conservation Programs,'' Report 
    from Environmental Noise Consultants, Inc., NIOSH, 1992.
    Royster, Julia D. et al., ``Development of a new standard laboratory 
    protocol for estimating the field attenuation of hearing protection 
    devices. Part I. Research of Working Group 11, Accredited Standards 
    Committee S12, Noise,'' Journal of the Acoustical Society of America, 
    99(3):1506-1526, March 1996.
    Royster, Larry H. et al., ``Potential Hearing Compensation Cost By Race 
    and Sex,'' Journal of Occupational Medicine, 20(12):801-806, December 
    1978.
    Royster, Larry H. et al., ``Guidelines for Developing an Effective 
    Hearing Conservation Program,'' Sound and Vibration, 16(5), May 1982.
    Royster, Larry H., ``Recommendations for the Labeling of Hearing 
    Protectors,'' Sound and Vibration, pp. 16-19, July 1995.
    Sataloff, Joseph et al., ``Hearing Loss From Exposure to Interrupted 
    Noise,'' Archives of Environmental Health, 18:972-981, June 1969.
    Sataloff, Joseph et al., ``Hearing Loss and Intermittent Noise 
    Exposure,'' Journal of Occupational Medicine, 26(9):649-656, September 
    1984.
    Savell, James F. and Edwin H. Toothman, ``Group Mean Hearing Threshold 
    Changes in a Noise-Exposed Industrial Population Using Personal Hearing 
    Protectors,'' American Industrial Hygiene Association Journal, pp. 23-
    27, January 1987.
    Savich, M.U., ``Attenuation Of Ear Muffs In Canadian Mines,'' CIM 
    Bulletin, pp. 58-65, December 1979.
    Scheiblechner, H., ``The Validity of the `Energy Principle' for Noise-
    Induced Hearing Loss'', Audiology, 13:93-111, 1974.
    Schmidek, Mark et al., ``Evaluation of Proposed Limits Intermittent 
    Noise Exposures with Temporary Threshold Shift as a Criterion,'' 
    American Industrial Hygiene Association Journal, August 1972.
    Schmidt, Jo Ann W. et al., ``Impact Of An Industrial Hearing 
    Conservation Program On Occupational Injuries For Males And Females,'' 
    Paper presented at the 99th Meeting of the Acoustical Society of 
    America, Atlanta, Georgia, April 21-25, 1980.
    Schneider, E.J. et al., ``The Progression of Hearing Loss from 
    Industrial Noise Exposures'', American Industrial Hygiene Association 
    Journal, 31:368-376, May-June 1970.
    Schwetz, F. et al., ``The Critical Intensity for Occupational Noise,'' 
    Acta Otolaryngol, 89:358-361, 1980.
    Scott, H.H., ``Noise Measuring Techniques,'' Ch. 17 in Handbook of 
    Noise Control, ed. C.M. Harris, McGraw-Hill Book Company, New York, NY, 
    pp. 1-36, 1957.
    Secretary of Labor, Mine Safety and Health Administration (MSHA) v. 
    Callanan Industries, Inc., 5 FMSHRC 1900 (November 1983).
    Secretary of Labor, Mine Safety and Health Administration (MSHA) v. A. 
    H. Smith, 6 FMSHRC 199 (February 1984).
    Seiler, John P. and Dennis A. Giardino, ``Calibration of Acoustical 
    Instruments for Noise Exposure Measurements,'' Sound and Vibration, 
    March 1996.
    Shaw, Edgar A.G., ``Occupational Noise Exposure and Noise-Induced 
    Hearing Loss: Scientific Issues, Technical Arguments and Practical 
    Recommendations,'' APS 707, NRCC/CNRC No. 25051, Prepared for the 
    Special Advisory Committee on the Ontario Noise Regulation, National 
    Research Council Canada, Division of Physics, pp. 1-64, October 30, 
    1985.
    Simpson, Thomas H. et al., ``Performance Evaluation of Hearing 
    Conservation Program Data in Small Companies,'' 1992 Hearing 
    Conservation Conference, University of Kentucky, Lexington, KY, pp. 25-
    32, April 1-4, 1992.
    Simpson, Thomas H. et al., ``Early Indicators of Hearing Conservation 
    Program Performance,'' Journal of the American Academy of Audiology, 
    5(5):300-306, September 1994.
    Sliney, David H., ``Review of the Threshold Limit Value for Noise,'' 
    Applied Occupational Environmental Hygiene, 8(7):618-623, July 1993.
    Smith, Curtis R., Letter to Larry Rabius, ``26% of the Mining Industry 
    Workers have Material Hearing Impairment,'' Industrial Hearing 
    Conservation Services Consultants, Auburn, Alabama, December 5, 1994.
    Standards Australia Acoustics-Hearing Conservation, AS 1269-1989, pp. 
    32.
    Stekelenburg, M., ``Noise at Work--Tolerable Limits and Medical 
    Control,'' American Industrial Hygiene Association Journal, 43:403-410, 
    June 1982.
    Sulkowski, Wieslaw J., Industrial Noise Pollution and Hearing 
    Impairment Problems of Prevention, Diagnosis and Certification 
    Criteria, National Technical Information Service pp. 1-243, 1980.
    Sulkowski, W.J. and Adam Lipowczan, ``Impulse Noise-Induced Hearing 
    Loss in Drop Forge Operators and the Energy Concept,'' Noise Control 
    Engineering, 18(1):24-29, January-February 1982.
    Suter, Alice H., ``The Relationship of the Exchange Rate to Noise-
    Induced Hearing Loss,'' Final Report of JRB Associates, McLean, VA, 
    December 13, 1983.
    Suter, Alice H., ``Hearing Conservation,'' Ch. 1 in Noise & Hearing 
    Conservation Manual (4th Edition), ed. Elliott H. Berger et al., 
    American Industrial Hygiene Association, Akron, OH, pp. 1-18, 1986.
    Suter, Alice H., ``The Development of Federal Noise Standards and 
    Damage Risk Criteria,'' Ch. 5 in Hearing Conservation in Industry, 
    Schools, and the Military, ed. D.M. Lipscomb, Little, Brown, and Co., 
    Boston, MA, pp. 45-66, 1988.
    Suter, Alice, ``Comments to the Department of Labor on OSHA's
    
    [[Page 66462]]
    
    Proposed Rule on Noise Standards,'' November 1994.
    Talbott, Evelyn O. et al., ``Noise-Induced Hearing Loss: A Possible 
    Marker for High Blood Pressure in Older Noise-Exposed Populations,'' 
    Journal of Occupational Medicine, 32(8):690-697, August 1990.
    Todilto Exploration and Development Corporation v. Secretary of Labor, 
    5 FMSHRC 1894 (1983).
    Tomei, Francesco et al., ``Vascular Effects of Noise,'' Angiology-
    Journal of Vascular Diseases, Rome, Italy, November 1992.
    United States Air Force, ``Air Force Occupational Safety and Health 
    Standard,'' AFOSH Standard 161-20, pp. 1-46, October 15, 1991.
    United States Air Force, ``Air Force Occupational Safety and Health 
    Standard,'' AFOSH Standard 48-19, pp. 1-48, December 17, 1993.
    United States Army, ``Hearing Conservation,'' Pamphlet 40-501, 
    Headquarters, Department of the Army, Washington, DC, pp. 1-15, August 
    27, 1991.
    United States Army Environmental Hygiene Agency, ``Noise Dosimetry and 
    Risk Assessment,'' USAEHA TG 181, May 1994.
    United States Department of Defense, ``Noise Limits for Army 
    Material,'' Washington, DC, Military Standard, MIL-STD-1474B (MI), pp. 
    1-44, June 18, 1979.
    United States Department of the Interior, U.S. Bureau of Mines, 
    ``Bulldozer Noise Control,'' Pittsburgh Research Center, Bolt, Beranek, 
    B. and Newman Inc., pp. 1-265, May 1980.
    United States Department of the Interior, U.S. Bureau of Mines, 
    ``Loader Noise Control,'' Pittsburgh Research Center, Bolt, Beranek, B. 
    and Newman Inc., pp. 1-133, June 1981.
    United States Navy, ``Hearing Conservation and Noise Abatement,'' 
    OPNAVINST 5100.23D Ch. 18, October 11, 1994.
    United Steelworkers of America, v. Marshall, 647 F. 2d 1189 (August 
    1980).
    Valoski, Michael P., ``The Magnitude of the Noise-Induced Hearing Loss 
    Problem in the Mining Industries,'' U.S. Department of Labor, 
    Informational Report IR 1220, March 1994.
    Villeneuve, E.O. and M. Caza, ``Noranda's Experience with a Hearing 
    Conservation Program, Part 1: Quebec Mining Operations,'' Annals of the 
    American Conference of Governmental Industrial Hygienists, 14:529-538, 
    1986.
    Ward, W. Dixon, ``Auditory Effects of Noise,'' Ch. 6 in Noise & Hearing 
    Conservation Manual (4th Edition), ed. Elliott H. Berger et al., 
    American Industrial Hygiene Association, Akron, OH, pp. 213-214, 1986.
    Ward, W. Dixon, ``Impulse/Impact Vs. Continuous Noise,'' Noise and 
    Hearing Loss, NIH Consensus Development Conference, pp. 47-49, January 
    22-24, 1990.
    Ward, Dixon and Christopher Turner, ``The Total Energy Concept as a 
    Unifying Approach to the Prediction of Noise Trauma and Its Application 
    to Exposure Criteria,'' in New Perspectives on Noise-Induced Hearing 
    Loss, ed. Roger P. Hamernik et al., Raven Press, New York, pp. 423-435, 
    1982.
    Wright, Mark, ``Education: The Key to Preventing Hearing Loss,'' 
    Occupational Health and Safety, pp. 38-39, January 1980.
    Government Publications by MESA/MSHA/USBOM
    Aljoe, William W. et al., ``The Bureau of Mines Noise-Control Research 
    Program--A 10-Year Review,'' U.S. Bureau of Mines Information Circular 
    IC 9004, pp. 1-85,1985.
    Aljoe, William W. et al., ``Test Apparatus for Measuring Sound Power 
    Levels of Drills,'' IC 9166, pp. 1-35, 1987.
    Bartholomae, Roy C. and Robert P. Parker, ``Mining Machinery Noise 
    Control Guidelines,'' U.S. Department of the Interior, A Bureau of 
    Mines Handbook, pp. 1-85, 1983.
    Bartholomae, Roy C. and R.S. Becker, ``Coal Cutting Mechanics and Noise 
    Generation,'' U.S. Department of the Interior, Bureau of Mines, Report 
    of Investigations RI 8743, pp. 1-27, 1983.
    Bartholomae, Roy C. et al., ``Measuring Noise from a Continuous Mining 
    Machine,'' U.S. Department of the Interior, Bureau of Mines, 
    Information Circular IC 8922, pp. 1-17, 1983.
    Bartholomae, Roy C., ``Active Noise Cancellation-Performance in a 
    Hearing Protector Under Ideal and Degraded Conditions,'' U.S. 
    Department of the Interior, Bureau of Mines, Report of Investigations 
    RI 9506, pp. 1-12, 1994.
    Bobick, Thomas G. and Dennis A. Giardino, ``The Noise Environment of 
    the Underground Coal Mine,'' U.S. Department of the Interior, Mining 
    Enforcement and Safety Administration, MESA Informational Report IR 
    1034, pp. 1-26, 1976.
    Bureau of Mines Staff, ``Noise Control,'' U.S. Department of the 
    Interior, Bureau of Mines, Information Circular IC 8986, pp. 1-141, 
    1984.
    Burks, Alton J. et al., ``Effects of Selected Physical Agents on the 
    Performance of Acoustically Absorptive Materials,'' U.S. Department of 
    the Interior, Bureau of Mines, Report of Investigations RI 9298, pp. 1-
    21, 1990.
    Chester, J.W. et al., ``Noise from Pneumatic Rock Drills Shape and Exit 
    Noise of an Exhaust Muffler,'' U.S. Department of the Interior, Bureau 
    of Mines, Report of Investigations, RI 6450, pp. 1-11, 1964.
    Daniel, J.H. et al., ``The Noise Exposure of Operators of Mobile 
    Machines in U.S. Surface Coal Mines,'' U.S. Department of the Interior, 
    Bureau of Mines, Information Circular IC 8841, pp. 1-24, 1981.
    Daniel, J.H. et al., ``Noise Control of Diesel-Powered Underground 
    Mining Machines,'' U.S. Department of the Interior, Bureau of Mines, 
    Information Circular IC 8837, pp. 1-29, 1981.
    Derzay, Raymond, ``Hearing Conservation for the Mineral Industry,'' 
    U.S. Department of the Interior, Bureau of Mines, Information Circular 
    IC 8564, pp. 1-42, 1972.
    DeWoody, R.T. et al., ``Noise from Pneumatic Rock Drills Analogy 
    Studies of Muffler Designs,'' U.S. Department of the Interior, Bureau 
    of Mines, Report of Investigations RI 6345, pp. 1-24, 1964.
    Durkt, George Jr., ``Field Evaluation of Hearing Protection Devices at 
    Surface Mining Environments,'' U.S. Department of Labor, Mine Safety 
    and Health Administration IR 1213, pp. 1-29, 1993.
    Giardino, Dennis A. and John P. Seiler, ``Noise Dosimeters: Past, 
    Present, and Future,'' U.S. Department of the Interior, Mining 
    Enforcement and Safety Administration, MESA Informational Report IR 
    1049, pp. 1-11, 1976.
    Giardino, Dennis A. et al., ``Noise Control of an Underground 
    Continuous Miner, Auger-Type,'' U.S. Department of the Interior, Mining 
    Enforcement and Safety Administration, MESA Informational Report IR 
    1056, pp. 1-57, 1977.
    Giardino, Dennis A. et al., ``MSHA Test Procedures and Acceptability 
    Criteria for Noise Dosimeters,'' U.S. Department of Labor, Mine Safety 
    and Health Administration,
    
    [[Page 66463]]
    
    Informational Report IR 1072, pp. 1-11, 1978.
    Giardino, Dennis A., ``Underground Noise Interference Effects of the 
    Personal Respirable Coal Mine Dust Sampler,'' U.S. Department of Labor, 
    Mine Safety and Health Administration, Informational Report IR 1127, 
    pp. 1-7, 1981.
    Giardino, Dennis A. and Leonard C. Marraccini, ``Noise in the Mining 
    Industry--An Overview,'' U.S. Department of Labor, Mine Safety and 
    Health Administration, Informational Report IR 1129, pp. 1-10, 1981.
    Giardino, Dennis A. and George Durkt, Jr., ``Evaluation of Muff Type 
    Hearing Protectors as Used in the Mining Industry,'' U.S. Department of 
    Labor, Mine Safety and Health Administration, Informational Report IR 
    1222, pp. 1-21, 1994.
    Kinevy, Paul T., ``In Plant Partial Noise Enclosures for the Mining 
    Industry,'' U.S. Department of Labor, Mine Safety and Health 
    Administration, Informational Report IR 1154, pp. 1-18, 1993.
    Kogut, Jon and Richard J. Goff, ``Analysis of Noise Reduction with 
    Earmuff Hearing Protectors under Field Conditions,'' U.S. Department of 
    Labor, Mine Safety and Health Administration, Information Report IR 
    1221, pp. 1-14, 1994.
    Lamonica, J.A. et al., ``Noise in Underground Coal Mines,'' U.S. 
    Department of the Interior, Bureau of Mines, Report of Investigations 
    RI 7550, pp. 1-11, 1971.
    Marraccini, Leonard C., ``Comparison of Hearing Protector Rating 
    Methods and Recommendations for Use in the Mining Industry,'' U.S. 
    Department of Labor, Mine Safety and Health Administration, 
    Informational Report IR 1176, pp. 1-28, 1987.
    Miller, William C., ``Noise from Pneumatic Rock Drills: Measurement and 
    Significance,'' U.S. Department of the Interior, Bureau of Mines, 
    Report of Investigations RI 6165, pp. 1-30, 1963.
    Muldoon, Terry L., ``Response Variations of a Microphone Worn on the 
    Human Body,'' U.S. Department of the Interior, Bureau of Mines, Report 
    of Investigation RI 7810, pp. 1-37, 1973.
    Pettitt, Mark R. and William W. Aljoe, ``Fabrication Manual for a 
    Reduced-Noise Auger Miner Cutting Head,'' U.S. Department of the 
    Interior, Bureau of Mines, Information Circular IC 8971, pp. 1-9, 1984.
    Pokora, R.J. et al., ``Retrofit Noise Control Modifications for 
    Crushing and Screening Equipment in the Nonmetallic Mining Industry, An 
    Applications Manual,'' U.S. Department of the Interior, Bureau of 
    Mines, Information Circular IC 8975, pp. 1-24, 1984.
    Seiler, J.P. et al., ``Noise Exposure in U.S. Coal Mines,'' U.S. 
    Department of Labor, Mine Safety and Health Administration, 
    Informational Report IR 1214, pp. 1-46, 1994.
    Seiler, John P. and Dennis A. Giardino, ``The Effect of Threshold on 
    Noise Dosimeter Measurements and Interpretation of their Results,'' 
    U.S. Department of Labor, Mine Safety and Health Administration, 
    Informational Report IR 1224, pp. 1-16, 1994.
    Stein, Robert R. and William W. Aljoe, ``Noise Test Report: Handheld 
    Pneumatic Rotary Drill,'' U.S. Department of the Interior, Bureau of 
    Mines, RI 9269, 1989.
    Stein, Robert R., ``Measuring the Sound Power Level of Percussion 
    Drills,'' U.S. Department of the Interior, Bureau of Mines, Report of 
    Investigations RI 9524, pp. 1-6, 1994.
    Stewart, Kenneth C. and Timothy Y. Yen,''Noise Dosimeter Performance,'' 
    U.S. Department of the Interior, Bureau of Mines, Report of 
    Investigations RI 7876, pp. 1-38, 1974.
    Summers, C.R. and J.N. Murphy, ``Noise Abatement of Pneumatic Rock 
    Drill,'' U.S. Department of the Interior, Bureau of Mines, Report of 
    Investigations RI 7998, pp. 1-45, 1974.
    U.S. Department of the Interior, Mining Enforcement Safety 
    Administration, Proceedings of the MESA Noise Control Conference, St. 
    Louis, Missouri, November 11-12, 1975, pp. 1-148.
    Valoski, Michael P., ``Improving Barrier Insertion Loss,'' U.S. 
    Department of Labor, Mine Safety and Health Administrration, 
    Informational Report IR 1117, pp. 1-17, 1980.
    Valoski, Michael P., ``The Magnitude of the Noise-Induced Hearing Loss 
    Problem in the Mining Industries,'' U.S. Department of Labor, Mine 
    Safety and Health Administration, Informational Report IR 1220, pp. 1-
    18, 1994.
    Valoski, Michael P. et al., ``Comparison of Noise Exposure Measurements 
    Conducted with Sound Level Meters and Noise Dosimeters under Field 
    Conditions,'' U.S. Department of Labor, Mine Safety and Health 
    Administration, Informational Report IR 1230, pp. 1-31, 1995.
    Yen, Timothy Y. and Kenneth C. Stewart, ``Noise Dosimeter Performance--
    A Second Evaluation,'' U.S. Department of Interior, Bureau of Mines, 
    Information Circular IC 8754, pp. 1-39, 1977.
    USBOM Noise Papers Presented in Public Forums or Published in Public 
    Access Publications
    Aljoe, William W. et al., ``Coal Cutting Noise Control,'' Paper 
    presented at Noise-Con 87, at State College, Pennsylvania, June 8-10, 
    1987, pp. 181-186.
    Bartholomae, Roy C. and John G. Kovac, ``USBM Develops a Low Noise 
    Percussion Drill,'' Paper presented at Inter-Noise 80, Miami, Florida, 
    December 8-10, 1980, pp. 317-320.
    Bartholomae, R.C. et al., ``Flammability Evaluation of Noise Control 
    Products for Use in Underground Coal Mines,'' Paper presented at Inter-
    Noise 80, Miami, Florida, December 8-10, 1980, pp. 637-640.
    Bartholomae, Roy C. and J. Alton Burks, ``U.S. Surface Coal Mine Mobile 
    Equipment: Operator Noise Exposures and Noise Controls,'' Annals of the 
    American Conference of Governmental Industrial Hygienists, 14:575-590, 
    1986.
    Bartholomae, Roy C. and Gerald W. Redmond, ``Noise-Induced Hearing 
    Loss--A Review,'' Annals of the American Conference of Governmental 
    Industrial Hygienists, 14:41-61, 1986.
    Bartholomae, Roy C. and Robert R. Stein, ``Noise Reducing Technologies 
    for Newly Designed Mining Percussion Drills,'' Paper presented at 
    Noise-Con 88, West Lafayette, Indiana, June 20-22, 1988, pp. 123-128.
    Bartholomae, Roy C. and Robert R. Stein, ``ANC vs Standard Hearing 
    Protectors Performance--Ideal & Non-Ideal Conditions,'' Paper presented 
    at Noise-Con 91, Tarrytown, New York, July 14-16, 1991, pp. 239-244.
    Bartholomae, Roy C. and James P. Rider, ``Active Noise Cancellation--
    Effectiveness for Auxiliary Mine Ventilation Systems,'' Paper presented 
    at Noise-Con 93, Williamsburg, Virginia, May 2-5, 1993, pp. 297-302.
    Bartholomae, Roy C. and J. Alton Burks, ``Impact of Anticipated Changes 
    in Mine Noise Regulations on the Coal Mining Industry,'' Paper 
    presented at Noise-Con 94, Ft. Lauderdale,
    
    [[Page 66464]]
    
    Florida, May 1-4, 1994, pp. 1017-1022.
    Bartholomae, Roy C. and J. Alton Burks, ``Impact of Anticipated Changes 
    in Mine Noise Regulations on Longwall Mining,'' Paper presented at 
    Longwall Show 1994, pp. 246-250.
    Bartholomae, Roy C., ``Small Diameter In-The-Hole Percussion Drilling 
    Tool for Percussion Drill Noise Control,'' Paper presented at Noise-Con 
    94, Ft. Lauderdale, Florida, May 1-4, 1994, pp. 175-180.
    Bartholomae, Roy C. and J. Alton Burks, ``Occupational Noise Exposures 
    in Underground Longwall Coal Mines,'' Paper presented at Inter-Noise 
    95, Newport Beach, California July 10-12, 1995, pp. 833-836.
    Bender, Erich K. et al., ``Noise Control of Jumbo-Mounted Percussive 
    Drills,'' Noise Control Engineering Journal 15(3): 128-137, November-
    December 1980.
    Burks, J.A. and E.R. Spencer, ``Measurement of Normal Incidence 
    Absorption Coefficient Using Sound Intensity,'' Paper presented at 
    Inter-Noise 89, Newport Beach, California, December 4-6, 1989, pp. 
    1077-1080.
    Burks, J.A. and E.R. Spencer, ``Effect of Fluids on the Performance of 
    Acoustical Materials,'' Paper presented at Noise-Con 91, Tarrytown, New 
    York, July 14-16, 1991, pp. 1-6.
    Burks, J.A. and Roy C. Bartholomae, ``Noise Reduction Potential of a 
    Variable Speed Driven Coal Mining Conveyor,'' Paper presented at 
    Proceeding of the SME Annual Meeting, Phoenix, Arizona, February 24-27, 
    1992, pp. 43-50.
    Burks, J.A. and Roy C. Bartholomae, ``Evaluation of Cap-Mounted and 
    Over-The-Head Earmuffs,'' Paper presented at Inter-Noise 92, Toronto, 
    Ontario, Canada, July 20-22, 1992, pp. 303-306.
    Casali, John G. et al., ``Physical vs. Psychophysical Measurement of 
    Hearing Protector Attenuation--a.k.a. MIRE vs. REAT,'' Sound and 
    Vibration, pp. 20-27, July 1995.
    Dixon, Nicholas R. and Roy S. Bartholomae, ``Front-End Loader Noise 
    Control,'' Paper presented at Inter-Noise 82, San Francisco, 
    California, May 17-19, 1982, pp. 277-280.
    Dutta, Piyush K. et al., ``Measurement and Analysis of the Stress Wave 
    Generated Rod Noise in Percussive Rock Drill,'' Paper presented at the 
    Proceedings of the Society for Experimental Stress Analysis Meeting, 
    Dearborn, Michigan, May 31-June 4, 1981, pp. 218-226.
    Dutta, Piyush K. et al., ``Development of a Low Noise Coal Mine Stoper 
    Drill,'' Paper presented at Noise-Con 81, Raleigh, North Carolina, June 
    8-10, 1981, pp. 245-248.
    Dutta, Piyush K. and Roy C. Bartholomae, ``Development of a Quiet Jumbo 
    Drill: Evaluation of Design Concepts,'' Paper presented at Noise-Con 
    83, Cambridge, Massachusetts, 1983, pp. 169-176.
    Galaitsis, A. et al., ``Noise Reduction of Chain Conveyors,'' Paper 
    presented at Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 
    169-172.
    Grant, Douglas C. et al., ``Computer Model Simulates Screening Process 
    under Variety of Conditions Part I Semi-empirical Approach Allows 
    Researchers more Latitude,'' Pit & Quarry, pp. 59-63, November 1982.
    Grant, Douglas C. et al., ``Computer Model Simulates Screening Process 
    under Variety of Conditions Part II Semi-empirical Approach Allows 
    Researchers more Latitude,'' Pit & Quarry, pp. 67-68, December 1982.
    Hawkes, I. and J.A. Burks, ``Investigation of Noise and Vibration in 
    Percussive Drill Rods,'' Int. J. Rock Mech. Sci. & Geomech. 16:363-376, 
    1979.
    Kohler, Jeffrey L. et al., ``A Real-Time Engineering Control for the 
    Reduction of Chain-Conveyor Noise,'' Paper presented at Noise-Con 93, 
    Williamsburg, Virginia, May 2-5, 1983, pp. 91-96.
    Kovac, John G., et al., ``Bulldozer Noise Control,'' SAE Technical 
    Paper Series, Paper presented at the International Off-Highway Meeting 
    and Exposition, MECCA, Milwaukee, September 8-11, 1980, pp. 1-6.
    Kovac, J.G. et al., ``Bulldozer Noise Control,'' Paper presented at 
    Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 457-460.
    Redmond, Gerald W. et al., ``Comparison of Earmuff Attenuation as 
    Measured by Psychophysical and Physical Methods,'' Paper presented at 
    Inter-Noise 80, Miami, Florida, December 8-10, 1980, pp. 659-662.
    Redmond, Gerald W. and J. Alton Burks, ``The Ambient Noise Floor in an 
    Earcup of a Hearing Protector Worn by a Human Subject,'' Annals of the 
    American Conference of Governmental Industrial Hygienists 14:557-563, 
    1986.
    Robertson, J. et al., ``Continuous Miner Noise,'' Transactions of the 
    American Society of Mechanical Engineers, 103:282-292, August 1981.
    Stein, Robert R. and William W. Aljoe, ``Concentric Drill Steels for 
    Noise Reduction of Percussion Drilling,'' Paper presented at Inter-
    Noise 86, Cambridge, USA, July 21-23, 1986, pp. 333-336.
    Stein, Robert R. and William W. Aljoe, ``Developing a Relationship 
    between Power Input and Sound Power Output for Percussion Drills,'' 
    Paper presented at Noise-Con 87, State College, Pennsylvania, June 8-
    10, 1987, pp. 177-180.
    Stein, Robert R. and Roy C. Bartholomae, ``Comparison of Sound Power 
    Measurement Techniques for Mining Drills: Sound Intensity vs ISO 
    3741,'' Paper presented at Inter-Noise 89, Newport Beach, California, 
    December 4-6, 1989, pp. 1021-1024.
    Stein, Robert R. and Roy C. Bartholomae, ``An Investigation of Sound 
    Intensity Techniques Applied to Impact Noise,'' Paper presented at 
    Noise-Con 90, Austin, Texas, October 15-17, 1990, pp. 403-408.
    Stein, Robert R. and Roy C. Bartholomae, ``Active Noise Control of Mine 
    Auxiliary Ventilation Fans,'' Paper presented at Noise-Con 91, 
    Tarrytown, New York, July 14-16, 1991, pp. 133-140.
    Stein, Robert R. and J. Alton Burks, ``Controlling Worker Exposure to 
    Noise on Longwall Faces,'' Paper presented at Proceeding of the SME 
    Annual Meeting, Phoenix, Arizona, February 24-27, 1992, pp. 279-285.
    Stephan, Robert W. et al., ``A Mathematical Model to Predict the 
    Potential Impact of Noise Control Measure on Reducing Miner 
    Overexposures,'' Annals of the American Conference of Governmental 
    Industrial Hygienists, 14:631-642, 1986.
    Wright, William H. and John G. Casali, ``The Effect of Passive and 
    Electronic Amplitude-Sensitive Hearing Protectors on the Detection of a 
    Warning Signal,'' NVLAP Report, March 1994.
    
    List of Subjects
    
    30 CFR Parts 56 and 57
    
        Metal and nonmetal, Mine safety and health, Noise.
    
    30 CFR Part 62
    
        Mine safety and health, Noise.
    
    30 CFR Parts 70 and 71
    
        Coal, Mine safety and health, Noise.
    
    
    [[Page 66465]]
    
    
        Dated: November 26, 1996.
    J. Davitt McAteer,
    Assistant Secretary for Mine Safety and Health.
    
        It is proposed to amend Chapter I of Title 30 of the Code of 
    Federal Regulations as follows:
    
    PART 56--[AMENDED]
    
        1. The authority citation for part 56 continues to read as follows:
    
        Authority: 30 U.S.C. 811, 957, 961.
    
        2. Section 56.5050 and the undesignated center heading preceding it 
    are removed.
    
    PART 57--[AMENDED]
    
        3. The authority citation for part 57 continues to read as follows:
    
        Authority: 30 U.S.C. 811, 957, 961.
    
        4. Section 57.5050 and the undesignated center heading preceding it 
    are removed.
    
    PART 70--[AMENDED]
    
        5. The authority citation for part 70 continues to read as follows:
    
        Authority: 30 U.S.C. 811 and 961.
    
        6. Subpart F (Secs. 70.500-70.511) is removed.
    
    PART 71--[AMENDED]
    
        7. The authority citation for part 71 continues to read as follows:
    
        Authority: 30 U.S.C. 811, 951, 957, 961.
    
        8. Subpart I (Secs. 71.800-71.805) is removed.
        9. Subchapter M is redesignated as subchapter I, subchapter N is 
    redesignated as subchapter K, and Subchapter N is reserved.
        10. A new Subchapter M is added, ``Uniform Mine Health 
    Regulations.''
        11. A new part 62 is added to new Subchapter M to read as follows:
    
    PART 62--OCCUPATIONAL NOISE EXPOSURE
    
    Sec.
    62.100  Purpose and scope; effective date.
    62.110  Definitions.
    62.120  Limitations on noise exposure.
    62.125  Hearing protectors.
    62.130  Training.
    62.140  Audiometric testing program.
    62.150  Audiometric test procedures.
    62.160  Evaluation of audiogram.
    62.170  Follow-up evaluation when audiogram invalid.
    62.180  Follow-up corrective measures when STS detected.
    62.190  Notification of results; reporting requirements.
    62.200  Access to records.
    62.210  Transfer of records.
    
        Authority: 30 U.S.C. 811, 857, 861.
    
    
    Sec. 62.100  Purpose and scope; effective date.
    
        The purpose of these standards is the prevention of occupational 
    noise-induced hearing loss among miners. This part sets forth mandatory 
    health standards for each surface and underground metal, nonmetal, and 
    coal mine subject to the Federal Mine Safety and Health Act of 1977. 
    The provisions of this part shall take effect (one year from the date 
    of publication of the final rule).
    
    
    Sec. 62.110  Definitions.
    
        The following definitions apply in this part:
        Access. The right to examine and copy records.
        Audiologist. A professional, specializing in the study and 
    rehabilitation of hearing, who is certified by the American Speech-
    Language-Hearing Association (ASHA) or licensed by a state board of 
    examiners.
        Baseline audiogram. The audiogram recorded pursuant to Sec. 62.140 
    against which subsequent audiograms are compared to determine the 
    extent of hearing loss, except in those specific situations in which 
    this part requires the use of a supplemental baseline audiogram for 
    such a purpose.
        Criterion level. The sound level which if constantly applied for 8 
    hours results in a dose of 100% of that permitted by the standard.
        Decibel (dB). A unit of measure of sound levels. MSHA defines 
    decibel in two different ways depending upon the use.
        (1) For measuring sound pressure levels, the decibel is 20 times 
    the common logarithm of the ratio of the measured sound pressure to the 
    standard reference pressure of 20 micropascals (Pa), which is 
    the threshold of normal hearing acuity at 1000 Hz.
        (2) For measuring hearing threshold levels, the decibel is the 
    difference between audiometric zero (reference pressure equal to 0 
    hearing threshold level) and the threshold of hearing of the individual 
    being tested at each test frequency.
        Decibel, A-weighted (dBA). Sound levels measured using the A-
    weighting network. A-weighting refers to the frequency response network 
    closely corresponding to the frequency response of the human ear. This 
    network attenuates sound energy in the lower and upper frequencies 
    (<1000 and="">5000 Hz) and slightly amplifies those frequencies between 
    1000 and 5000 Hz to which the ear is more sensitive.
        Designated representative. Any individual or organization to whom a 
    miner gives written authorization to exercise a right of access to 
    records.
        Exchange rate. The amount of increase in sound level, in decibels, 
    which would require halving of the allowable exposure time to maintain 
    the same noise dose.
        Hearing conservation program (HCP). The term is used in this part 
    as a generic reference to the requirements of Secs. 62.140 through 
    62.190, such as audiometric testing, evaluation and follow-up 
    examinations.
        Hearing protector. Any device or material, capable of being worn on 
    the head or in the ear canal, sold wholly or in part on the basis of 
    its ability to reduce the level of sound entering the ear, and that has 
    a scientifically accepted indicator of noise reduction value.
        Hertz (Hz). Unit of measurement of frequency numerically equal to 
    cycles per second. The audible range of frequencies for humans with 
    normal hearing is 20 to 20000 Hz.
        Medical pathology. A condition or disease affecting the ear.
        Qualified technician. A technician who has been certified by the 
    Council for Accreditation in Occupational Hearing Conservation (CAOHC) 
    or by another recognized organization offering equivalent 
    certification.
        Reportable hearing loss. A change in hearing acuity for the worse, 
    relative to the miner's baseline audiogram or, in the case of a 
    supplemental baseline audiogram established pursuant to 
    Sec. 62.140(d)(2), relative to such supplemental baseline audiogram, of 
    an average of 25 dB or more at 2000, 3000, and 4000 Hz in either ear.
        Sound level. The sound pressure level measured in decibels using a 
    weighting network (e.g., A-weighted) and exponential time averaging 
    (e.g., slow response). The A-weighting network and the slow response 
    time are defined in ANSI S1.4-1983, ``American National Standard 
    Specification for Sound Level Meters.''
        Standard threshold shift (STS). A change in hearing acuity for the 
    worse relative to the miner's baseline audiogram, or relative to the 
    most recent supplemental baseline audiogram where one has been 
    established, of an average of 10 dB or more at 2000, 3000, and 4000 Hz 
    in either ear.
        Supplemental baseline audiogram. An annual audiogram designated, as 
    a result of the circumstances set forth in Sec. 62.140(d)(1) or those 
    set forth in Sec. 62.140(d)(2), to be utilized in lieu of a miner's 
    original baseline audiogram in measuring changes in hearing acuity.
    
    [[Page 66466]]
    
        Time-weighted average-8 hour (TWA8). That sound level, which 
    if constant over 8 hours, would result in the same noise dose as is 
    measured.
    
    
    Sec. 62.120  Limitations on noise exposure.
    
        (a) Dose determination.
        (1) A miner's noise dose (D) is computed by the formula: D = 
    100(C1/T1 + C2/T2 + * * * + Cn/Tn), where 
    Cn is the total time of exposure at a specified sound level, and 
    Tn is the reference duration of exposure at that sound level set 
    forth in Table 62-1.
        (2) Table 62-2 is to be utilized when converting noise measurements 
    from dosage readings to equivalent TWA8 readings.
    
                         Table 62-1.--Reference Duration                    
    ------------------------------------------------------------------------
                                                                  Reference 
                 L (dBA, slow-response sound level)              Duration, T
                                                                    (hour)  
    ------------------------------------------------------------------------
    85.........................................................         16.0
    86.........................................................         13.9
    87.........................................................         12.1
    88.........................................................         10.6
    89.........................................................          9.2
    90.........................................................          8.0
    91.........................................................          7.0
    92.........................................................          6.1
    93.........................................................          5.3
    94.........................................................          4.6
    95.........................................................          4.0
    96.........................................................          3.5
    97.........................................................          3.0
    98.........................................................          2.6
    99.........................................................          2.3
    100........................................................          2.0
    101........................................................          1.7
    102........................................................          1.5
    103........................................................          1.3
    104........................................................          1.1
    105........................................................          1.0
    106........................................................         0.87
    107........................................................         0.76
    108........................................................         0.66
    109........................................................         0.57
    110........................................................         0.50
    111........................................................         0.44
    112........................................................         0.38
    113........................................................         0.33
    114........................................................         0.29
    115........................................................         0.25
    ------------------------------------------------------------------------
    Note: For any value, the reference duration (T) in hours is computed by:
      T = 8/2(L-90)/5, where L is the measured A-weighted, slow-response    
      sound level.                                                          
    
    
            Table 62-2.--Conversion From ``Dose'' to Equivalent TWA8        
    ------------------------------------------------------------------------
                   Dose (percent noise exposure)                     TWA8   
    ------------------------------------------------------------------------
    25.........................................................         80.0
    29.........................................................         81.0
    33.........................................................         82.0
    38.........................................................         83.0
    44.........................................................         84.0
    50.........................................................         85.0
    57.........................................................         86.0
    66.........................................................         87.0
    76.........................................................         88.0
    87.........................................................         89.0
    100........................................................         90.0
    115........................................................         91.0
    132........................................................         92.0
    152........................................................         93.0
    174........................................................         94.0
    200........................................................         95.0
    230........................................................         96.0
    264........................................................         97.0
    303........................................................         98.0
    350........................................................         99.0
    400........................................................        100.0
    460........................................................        101.0
    530........................................................        102.0
    610........................................................        103.0
    700........................................................        104.0
    800........................................................        105.0
    920........................................................        106.0
    1056.......................................................        107.0
    1213.......................................................        108.0
    1393.......................................................        109.0
    1600.......................................................        110.0
    1838.......................................................        111.0
    2111.......................................................        112.0
    2425.......................................................        113.0
    2786.......................................................        114.0
    3200.......................................................        115.0
    3676.......................................................        116.0
    4222.......................................................        117.0
    4850.......................................................        118.0
    5572.......................................................        119.0
    6400.......................................................        120.0
    ------------------------------------------------------------------------
    Interpolate between the values found in this Table, or extend the table,
      by using the formula: TWA8 = 16.61 log10 (D/100) + 90.                
    
        (3) A miner's noise exposure measurement shall:
        (i) Not be adjusted on account of the use of any hearing protector;
        (ii) Integrate all sound levels from 80 dBA to at least 130 dBA 
    during the miner's full workshift;
        (iii) Use a 90 dBA criterion level and a 5-dB exchange rate; and
        (iv) Use an A-weighting and a slow-response instrument setting.
        (b) Action level. When a miner's noise exposure exceeds a TWA8 
    of 85 dBA during any workshift, or equivalently a dose of 50%, the 
    operator shall take the actions specified in paragraphs (b)(1) and (2) 
    of this section and, at the request of the miner, also take the actions 
    specified in paragraph (b)(3) of this section.
        (1) An operator shall provide the miner training that includes the 
    instruction required by Sec. 62.130, at the time exposure exceeds the 
    action level and every 12 months thereafter that exposure continues to 
    exceed the action level.
        (2) An operator shall enroll the miner in a hearing conservation 
    program which shall meet the requirements of Secs. 62.140 through 
    62.190. Moreover, the operator shall, with respect to any miner 
    enrolled in such program, provide hearing protection in accordance with 
    the requirements of Sec. 62.125 until such time as a baseline audiogram 
    has been obtained. If it takes more than 6 months to conduct the 
    baseline audiogram, or if the miner is determined to have incurred an 
    STS, the operator shall ensure that the hearing protection is provided 
    to the miner and worn by the miner.
        (3) At the request of any miner, the operator shall provide hearing 
    protection to the miner in accordance with the requirements of 
    Sec. 62.125.
        (c) Permissible exposure level (PEL). No miner shall be exposed to 
    noise exceeding a TWA8 of 90 dBA (PEL) during any workshift, or 
    equivalently a dose of 100%.
        (1) If a miner's noise exposure exceeds the PEL, the operator 
    shall, in addition to taking the actions required under paragraph (b) 
    of this section, use all feasible engineering and administrative 
    controls to reduce the miner's noise exposure to the PEL. When 
    administrative controls are used to reduce a miner's exposure, the 
    operator shall post these procedures on the mine bulletin board and 
    provide a copy to affected miners.
        (2) If a miner's noise exposure exceeds the PEL despite the use of 
    the controls required by paragraph (c)(1) of this section, the operator 
    shall take the actions required by this paragraph for that miner.
        (i) The operator shall use the controls required by paragraph 
    (c)(1) of this section to reduce the miner's noise exposure to as low a 
    level as is feasible.
        (ii) The operator shall ensure that a miner whose exposure exceeds 
    the PEL takes the hearing examinations offered through enrollment in 
    the hearing conservation program.
        (iii) The operator shall provide hearing protection to a miner 
    whose exposure exceeds the PEL and shall ensure the use thereof. The 
    hearing protection shall be provided and used in accordance with the 
    requirements of Sec. 62.125.
        (d) Dual hearing protection level. Whenever a miner's noise 
    exposure exceeds a TWA8 of 105 dBA during any workshift, or 
    equivalently a dose of 800%, the operator shall ensure that the miner 
    is provided and uses both ear plug and ear muff type protectors 
    pursuant to Sec. 62.125.
        (e) Ceiling level. At no time shall a miner be exposed to sound 
    levels exceeding 115 dBA.
    
    [[Page 66467]]
    
        (f) Operator exposure evaluation; employee notification.
        (1) Operators shall establish a system of monitoring which 
    effectively evaluates each miner's noise exposure.
        (2) Whenever a miner's exposure is determined to exceed the action 
    level, the permissible exposure level, the dual hearing protection 
    level, or the ceiling level established by this section, according to 
    exposure evaluations conducted either by the operator or by 
    representatives of the Secretary of Labor, and the miner has not 
    received notification of exposure at such level within the prior 12 
    months, the operator shall, within 15 calendar days, notify the miner 
    in writing of the exposure determination and the corrective action 
    being taken. The operator shall maintain at the mine site a copy of any 
    such miner notification, or a list on which the relevant information 
    about that miner's notice is recorded, for the duration of the affected 
    miner's exposure above the action level and for at least 6 months 
    thereafter.
    
    
    Sec. 62.125  Hearing protectors.
    
        When hearing protection is required pursuant to this part, an 
    operator shall:
        (a) Allow the miner, after such miner has received the training 
    specified by Sec. 62.130 at least once, to choose a hearing protector 
    from at least one muff type and one plug type, and in the event dual-
    hearing protection is required, to choose one of each type;
        (b) In those cases in which the operator is required to ensure the 
    use by a miner of hearing protection, ensure that the protector is worn 
    by the miner when exposed to sound levels which are required to be 
    integrated into a miner's noise exposure measurement;
        (c) Ensure that the hearing protection is fitted and maintained in 
    accordance with the manufacturer's instructions;
        (d) Provide the hearing protectors and necessary replacements at no 
    cost to the miner; and
        (e) Allow the miner to choose a different hearing protector if 
    wearing the selected protector is subsequently precluded due to medical 
    pathology of the ear.
    
    
    Sec. 62.130  Training.
    
        (a) Miner training required by this part shall include the 
    following instruction:
        (1) The effects of noise on hearing;
        (2) The purpose and value of wearing hearing protectors;
        (3) The advantages and disadvantages of the hearing protectors to 
    be offered;
        (4) The care, fitting, and use of the hearing protector worn by the 
    miner and the various types of hearing protectors offered by the 
    operator;
        (5) The general requirements of this part;
        (6) The operator's and miner's respective tasks in maintaining mine 
    noise controls; and
        (7) The purpose and value of audiometric testing and a summary of 
    the procedures.
        (b) The training requirement under this part shall only be met if 
    the operator certifies the date and type of training given each miner. 
    The type of training may be initial noise training of a miner, annual 
    retraining of a miner, or special retraining required for a miner as a 
    result of the detection of an STS. The certification shall be signed by 
    the person conducting the training. The operator shall maintain the 
    miner's most recent certification at the mine site for as long as the 
    miner is exposed to noise above the level which required the training 
    and for at least 6 months thereafter.
    
    
    Sec. 62.140  Audiometric testing program.
    
        (a) Audiometric tests performed pursuant to this part shall be 
    conducted by a physician, an audiologist, or a qualified technician 
    under the direction or supervision of a physician or an audiologist, 
    and pursuant to the procedures set forth in Sec. 62.150.
        (b) Baseline audiogram. A miner enrolled in a hearing conservation 
    program shall be offered a valid baseline audiogram of the miner's 
    hearing acuity against which subsequent annual audiograms can be 
    compared.
        (1) The valid baseline audiogram shall be offered within 6 months 
    of enrolling the miner in an HCP, except that where mobile test vans 
    are used to meet the audiometric test requirements of this section, the 
    valid baseline audiogram shall be offered within 12 months of enrolling 
    the miner in an HCP. An existing audiogram of the miner's hearing 
    acuity may be used as the baseline audiogram if it meets the 
    audiometric testing requirements of this part.
        (2) The operator shall not expose the miner to workplace noise for 
    at least 14 hours before conducting the baseline audiogram. Hearing 
    protectors shall not be used as a substitute for this quiet period.
        (3) The operator shall notify miners of the need to avoid high 
    levels of noise during the 14-hour quiet period before taking the 
    baseline audiogram.
        (4) The operator shall not revise either a miner's baseline 
    audiogram, or supplemental baseline audiogram where one has been 
    established, due to changes in enrollment status in the HCP except for 
    periods of unemployment exceeding 6 consecutive months.
        (c) Annual audiogram. After establishing the baseline audiogram, 
    the operator shall offer a subsequent valid audiogram at intervals not 
    exceeding 12 months for as long as the miner remains in the HCP.
        (d) Supplemental baseline audiogram. An annual audiogram shall be 
    deemed to be a supplemental baseline audiogram when, in the judgment of 
    the audiologist or physician:
        (1) The standard threshold shift (STS) revealed by the audiogram is 
    permanent; or
        (2) The hearing threshold shown in the annual audiogram indicates 
    significant improvement over the baseline audiogram.
    
    
    Sec. 62.150  Audiometric test procedures.
    
        (a) The operator shall assure that all audiometric testing required 
    under this part is conducted in accordance with scientifically 
    validated procedures. Audiometric tests shall be pure tone, air 
    conduction, hearing threshold examinations, with test frequencies 
    including as a minimum 500, 1000, 2000, 3000, 4000, and 6000 Hz. Each 
    ear shall be tested separately.
        (b) The operator shall obtain from the physician, audiologist, or 
    qualified technician who conducts an audiometric test required under 
    this part, a certification that the testing was conducted in accordance 
    with paragraph (a) of this section.
        (c) The operator shall compile an audiometric test record for each 
    miner tested. Such record shall include the following:
        (1) Name and job classification of the miner who has undergone the 
    audiometric test(s);
        (2) A copy of all of the miner's audiograms required under this 
    part;
        (3) Certification(s) as required under paragraph (b) of this 
    section;
        (4) Any exposure determination for the miner; and
        (5) The results of any follow-up examination(s).
        (d) Audiometric test records shall be maintained at the mine site 
    for the duration of the affected miner's employment plus at least 6 
    months.
    
    
    Sec. 62.160  Evaluation of audiogram.
    
        (a) The operator shall:
        (1) Inform persons evaluating audiograms of the requirements of 
    this part and provide them with a copy of the miner's audiometric test 
    records;
        (2) Have a physician, an audiologist, or a qualified technician who 
    is under the direction or supervision of a physician or audiologist:
        (i) Determine if the audiogram is valid; and
    
    [[Page 66468]]
    
        (ii) Determine if an STS or a reportable hearing loss, as defined 
    in this part, has occurred;
        (3) Instruct the physician or audiologist not to reveal to the 
    operator any specific findings or diagnoses unrelated to the miner's 
    exposure to noise or wearing of hearing protectors without the written 
    consent of the miner; and
        (4) Obtain the results, and the interpretation of the results of 
    any audiogram conducted under this part within 30 calendar days of 
    conducting the audiogram.
        (b)(1) The operator shall conduct an audiometric retest within 30 
    calendar days of receiving a determination that a required audiogram is 
    invalid and that any medical pathology has improved to the point that a 
    valid audiogram may be obtained.
        (2) If the results of an annual audiogram demonstrate that the 
    miner has incurred an STS or reportable hearing loss, the operator may 
    conduct one retest within 30 calendar days of receiving the results of 
    the audiogram and consider the results of the retest as the annual 
    audiogram.
        (c) In determining whether an STS or reportable hearing loss has 
    occurred, allowance may be made for the contribution of aging 
    (presbycusis) to the change in hearing level by adjusting the 
    audiograms used in making those determinations according to the 
    following procedures:
        (1) Determine from Tables 62-3 or 62-4 the age correction values 
    for the miner by:
        (i) Finding the age at which the baseline audiogram, or 
    supplemental baseline audiogram as appropriate, was taken, and 
    recording the corresponding values of age corrections at 2000, 3000, 
    and 4000 Hz; and
        (ii) Finding the age at which the most recent audiogram was taken 
    and recording the corresponding values of age corrections at 2000, 
    3000, and 4000 Hz.
        (2) Subtract the value determined in paragraph (c)(1)(i) of this 
    section from the value determined in paragraph (c)(1)(ii) of this 
    section. The differences calculated represent that portion of the 
    change in hearing that may be due to aging.
        (3) Subtract the value determined in paragraph (c)(2) of this 
    section from the hearing threshold level found in the annual audiogram 
    to obtain the adjusted annual audiogram hearing threshold level.
        (4) Subtract the hearing threshold in the baseline audiogram or 
    supplemental baseline audiogram from the adjusted annual audiogram 
    hearing threshold level determined in paragraph (c)(3) of this section 
    to obtain the age-corrected threshold shift.
    
             Table 62-3.--Age Correction Value in Decibels for Males        
    ------------------------------------------------------------------------
                                                        Audiometric test    
                                                        frequencies (Hz)    
                        Years                     --------------------------
                                                     2000     3000     4000 
    ------------------------------------------------------------------------
    20 or younger................................        3        4        5
    21...........................................        3        4        5
    22...........................................        3        4        5
    23...........................................        3        4        6
    24...........................................        3        5        6
    25...........................................        3        5        7
    26...........................................        4        5        7
    27...........................................        4        6        7
    28...........................................        4        6        8
    29...........................................        4        6        8
    30...........................................        4        6        9
    31...........................................        4        7        9
    32...........................................        5        7       10
    33...........................................        5        7       10
    34...........................................        5        8       11
    35...........................................        5        8       11
    36...........................................        5        9       12
    37...........................................        6        9       12
    38...........................................        6        9       13
    39...........................................        6       10       14
    40...........................................        6       10       14
    41...........................................        6       10       14
    42...........................................        7       11       16
    43...........................................        7       12       16
    44...........................................        7       12       17
    45...........................................        7       13       18
    46...........................................        8       13       19
    47...........................................        8       14       19
    48...........................................        8       14       20
    49...........................................        9       15       21
    50...........................................        9       16       22
    51...........................................        9       16       23
    52...........................................       10       17       24
    53...........................................       10       18       25
    54...........................................       10       18       26
    55...........................................       11       19       27
    56...........................................       11       20       28
    57...........................................       11       21       29
    58...........................................       12       22       31
    59...........................................       12       22       32
    60 or older..................................       13       23       33
    ------------------------------------------------------------------------
    
    
            Table 62-4.--Age Correction Value in Decibels for Females       
    ------------------------------------------------------------------------
                                                        Audiometric test    
                                                        frequencies (Hz)    
                        Years                     --------------------------
                                                     2000     3000     4000 
    ------------------------------------------------------------------------
    20 or younger................................        4        3        3
    21...........................................        4        4        3
    22...........................................        4        4        4
    23...........................................        5        4        4
    24...........................................        5        4        4
    25...........................................        5        4        4
    26...........................................        5        5        4
    27...........................................        5        5        5
    28...........................................        5        5        5
    29...........................................        5        5        5
    30...........................................        6        5        5
    31...........................................        6        6        5
    32...........................................        6        6        6
    33...........................................        6        6        6
    34...........................................        6        6        6
    35...........................................        6        7        7
    36...........................................        7        7        7
    37...........................................        7        7        7
    38...........................................        7        7        7
    39...........................................        7        8        8
    40...........................................        7        8        8
    41...........................................        8        8        8
    42...........................................        8        9        9
    43...........................................        8        9        9
    44...........................................        8        9        9
    45...........................................        8       10       10
    46...........................................        9       10       10
    47...........................................        9       10       11
    48...........................................        9       11       11
    49...........................................        9       11       11
    50...........................................       10       11       12
    51...........................................       10       12       12
    52...........................................       10       12       13
    53...........................................       10       13       13
    54...........................................       11       13       14
    55...........................................       11       14       14
    56...........................................       11       14       15
    57...........................................       11       15       15
    58...........................................       12       15       16
    59...........................................       12       16       16
    60 or older..................................       12       16       17
    ------------------------------------------------------------------------
    
    Sec. 62.170  Follow-up evaluation when audiogram invalid.
    
        (a) If a valid audiogram cannot be obtained due to a suspected 
    medical pathology of the ear which the physician or audiologist 
    believes was caused or aggravated by the miner's exposure to noise or 
    the wearing of hearing protectors, the operator shall refer the miner 
    for a clinical audiological evaluation or an otological examination, as 
    appropriate, at no cost to the miner.
        (b) The operator shall instruct the physician or audiologist that 
    if a valid audiogram cannot be obtained due to a suspected medical 
    pathology of the ear which the physician or audiologist concludes is 
    unrelated to the miner's exposure to noise or the wearing of hearing 
    protectors, the physician or audiologist shall inform the miner of the 
    need for an otological examination.
        (c) The operator shall instruct the physician or audiologist not to 
    reveal to the operator any specific findings or diagnoses unrelated to 
    the miner's exposure to noise or the wearing of hearing protectors 
    without the written consent of the miner.
    
    [[Page 66469]]
    
    Sec. 62.180  Follow-up corrective measures when STS detected.
    
        Unless a physician or audiologist determines that an STS is neither 
    work-related nor aggravated by occupational noise exposure, the 
    operator shall within 30 calendar days of receiving evidence of an STS 
    or receiving the results of a retest confirming an STS:
        (a) Retrain the miner, including the instruction required by 
    Sec. 62.130;
        (b) Provide the miner with the opportunity to select a hearing 
    protector, or a different hearing protector if the miner has previously 
    selected a hearing protector, from among those offered by the operator 
    pursuant to Sec. 62.125; and
        (c) Review the effectiveness of any engineering and administrative 
    controls to identify and correct any deficiencies.
    
    
    Sec. 62.190  Notification of results; reporting requirements.
    
        (a) Within 10 working days of receiving the results of an 
    audiogram, or receiving the results of a follow-up evaluation required 
    under Sec. 62.170(a), the operator shall notify the miner in writing 
    of:
        (1) The results and interpretation of the audiometric test, 
    including any finding of an STS or reportable hearing loss; and
        (2) If applicable, the need and reasons for any further testing or 
    evaluation.
        (b) If evaluation of the audiogram shows that a miner has incurred 
    a reportable hearing loss as defined in this part, the operator shall 
    report such loss to MSHA as a noise-induced hearing loss in accordance 
    with part 50 of this title unless a physician or audiologist has 
    determined that the loss is neither work-related nor aggravated by 
    occupational noise exposure.
    
    
    Sec. 62.200  Access to records.
    
        (a) The authorized representatives of the Secretaries of Labor and 
    Health and Human Services shall have access to all records required 
    under this part. Upon written request, the operator shall provide, 
    within 15 calendar days of the request, access to records as indicated 
    below:
        (1) The miner, former miner, or, with the miner's written consent, 
    the miner's designated representative shall have access to all records 
    that the operator is required to maintain for that individual miner 
    under this part; and
        (2) The miners' representative shall in all cases have access to 
    training records compiled pursuant to section Sec. 62.130, and to 
    copies of notices made pursuant to Sec. 62.120(f)(2), for the miners 
    whom they represent.
        (b) Upon termination of a miner's employment, the operator shall 
    provide the miner without cost with a copy of all records that the 
    operator is required to maintain for that individual miner under this 
    part.
        (c) If a person who has access to certain records under this 
    section requests a copy of a record, the operator shall provide the 
    first copy of such record requested by a person at no cost to that 
    person, and any additional copies requested by that person at 
    reasonable cost.
    
    
    Sec. 62.210  Transfer of records.
    
        (a) Whenever an operator ceases to do business, that operator shall 
    transfer all records required to be maintained by this part, or a copy 
    thereof, to any successor operator who shall receive these records and 
    maintain them for the required period.
        (b) The successor operator shall use the baseline audiogram, or 
    supplemental baseline audiogram as appropriate, obtained by the 
    original operator for determining the existence of an STS or reportable 
    hearing loss.
    
    [FR Doc. 96-30733 Filed 12-16-96; 8:45 am]
    BILLING CODE 4510-43-P
    
    
    

Document Information

Published:
12/17/1996
Department:
Mine Safety and Health Administration
Entry Type:
Proposed Rule
Action:
Proposed rule.
Document Number:
96-30733
Dates:
Comments must be received on or before February 18, 1997. Submit written comments on the information collection requirements by February 18, 1997.
Pages:
66348-66469 (122 pages)
RINs:
1219-AA53: Noise Standard
RIN Links:
https://www.federalregister.gov/regulations/1219-AA53/noise-standard
PDF File:
96-30733.pdf
CFR: (34)
30 CFR 62.125)
30 CFR 62.125.)
30 CFR 62.120(a)
30 CFR 62.120(a)
30 CFR 1910.20(a)-(e)
More ...