99-14640. Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of Certain Chemicals of Interest to Occupational Safety and Health Administration  

  • [Federal Register Volume 64, Number 110 (Wednesday, June 9, 1999)]
    [Proposed Rules]
    [Pages 31074-31090]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 99-14640]
    
    
    
    [[Page 31073]]
    
    _______________________________________________________________________
    
    Part VI
    
    
    
    
    
    Environmental Protection Agency
    
    
    
    
    
    _______________________________________________________________________
    
    
    
    40 CFR Part 799
    
    
    
    Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of 
    Certain Chemicals of Interest to Occupational Safety and Health 
    Administration; Proposed Rule
    
    Federal Register / Vol. 64, No. 110 / Wednesday, June 9, 1999 / 
    Proposed Rules
    
    [[Page 31074]]
    
    
    
    ENVIRONMENTAL PROTECTION AGENCY
    
    40 CFR Part 799
    
    [OPPTS-42196; FRL-5760-3]
    RIN 2070-AB07
    
    
    Proposed Test Rule for In Vitro Dermal Absorption Rate Testing of 
    Certain Chemicals of Interest to Occupational Safety and Health 
    Administration
    
    AGENCY: Environmental Protection Agency (EPA).
    
    ACTION: Proposed rule.
    
    -----------------------------------------------------------------------
    
    SUMMARY: EPA is proposing a test rule under section 4(a) of the Toxic 
    Substances Control Act (TSCA) to require manufacturers, importers, and 
    processors of 47 chemical substances of interest to the Occupational 
    Safety and Health Administration (OSHA) to conduct in vitro dermal 
    absorption rate testing. These chemicals, and others, were designated 
    for in vitro dermal absorption rate testing in the 31st, 32nd, and 35th 
    Reports of the TSCA Section 4(e) Interagency Testing Committee (ITC) to 
    the EPA Administrator. The dermal absorption rate data obtained under 
    this testing program would be used to support OSHA's development of 
    ``skin designations'' for the chemical substances included in this 
    proposed rule. Skin designations are used by OSHA to provide specific 
    guidance to employers concerning whether changes should be made to 
    processes involving chemical substances in order to reduce the hazard 
    of systemic toxicity from dermal absorption of these chemicals. Changes 
    to a process might include changes in engineering controls or changes 
    in the use of or type of personal protective equipment. Skin 
    designations alert industrial hygienists, employers, and workers to 
    potential adverse health effects resulting from dermal exposure to 
    chemicals in the workplace. Persons who export or intend to export any 
    chemical substance included in the final rule based on this proposed 
    rule will be subject to the export notification requirements in TSCA 
    section 12(b)(1).
    
    DATES: Comments, identified by docket control number OPPTS-42196, must 
    be received by EPA on or before August 9, 1999. Your request to present 
    oral comments must be in writing and must be received by EPA on or 
    before July 9, 1999.
    
    ADDRESSES: Comments may be submitted by mail, electronically, or in 
    person. Follow the detailed instructions for each method as provided in 
    Unit I.C. of the ``SUPPLEMENTARY INFORMATION'' section of this 
    preamble. To ensure proper receipt by EPA, your comments must identify 
    docket control number OPPTS-42196 in the subject line on the first page 
    of your response.
    
    FOR FURTHER INFORMATION CONTACT: For general information: Christine 
    Augustyniak, Associate Director, Environmental Assistance Division 
    (7408), Office of Pollution Prevention and Toxics, Environmental 
    Protection Agency, 401 M St., SW., Washington, DC 20460; telephone 
    number: (202) 554-1404; TDD: (202) 554-0551; e-mail address: TSCA-
    Hotline@epa.gov.
        For technical information: Keith Cronin, Project Manager, Chemical 
    Control Division (7405), Office of Pollution Prevention and Toxics, 
    Environmental Protection Agency, 401 M St., SW., Washington, DC 20460; 
    telephone number: (202) 260-8157; fax number: (202) 260-1096; e-mail 
    address: cronin.keith@epa.gov.
    
    SUPPLEMENTARY INFORMATION:
    
    I. General Information
    
    A. Does This Action Apply To Me?
    
        You may be affected by this action, if you manufacture (defined by 
    statute to include import) or process any of the chemical substances 
    that are listed in Table 2 of this unit. Use of the term 
    ``manufacture'' in this preamble will encompass ``import,'' unless 
    otherwise stated. In addition, as described in Unit VI. of this 
    preamble, once the Agency issues the final rule, any person who 
    exports, or intends to export, one of these chemical substances will be 
    subject to the export notification requirements in 40 CFR part 707, 
    subpart D. The export notification requirements do not apply until the 
    Agency issues a final test rule, and then, only apply to exports of the 
    chemical substances that are contained in the final test rule. 
    Therefore, entities potentially affected by this proposed rule may 
    include, but are not limited to:
    
    
                      Table 1.-- Entities Potentially Affected by the Proposed Testing Requirements
    ----------------------------------------------------------------------------------------------------------------
                                                                                             Examples of potentially
               Type of entity                       SIC                     NAICS               affected entities
    ----------------------------------------------------------------------------------------------------------------
    Chemical manufacturers and importers  28, 2911                 325, 32411               Persons who manufacture
                                                                                             (defined by statute to
                                                                                             include import) one or
                                                                                             more of the subject
                                                                                             chemical substances
    -------------------------------------
    Chemical processors                   28, 2911                 325, 32411               Persons who process one
                                                                                             or more of the subject
                                                                                             chemical substances.
    ----------------------------------------------------------------------------------------------------------------
    
    
        This listing is not intended to be exhaustive, but rather provides 
    a guide for readers regarding entities likely to be affected by this 
    action. Other types of entities not listed in Table 1 of this unit 
    could also be affected. The Standard Industrial Classification (SIC) 
    codes and the North American Industrial Classification System (NAICS) 
    codes have been provided to assist you and others in determining 
    whether this action might apply to certain entities. To determine 
    whether you or your business is affected by this action, you should 
    carefully examine the applicability provisions in Unit V.C. of this 
    preamble entitled ``Would I Be Required To Test Under This Rule?'' and 
    consult the proposed regulatory text in Sec. 799.5115. If you have any 
    questions regarding the applicability of this action to a particular 
    entity, consult the technical person listed in ``FOR FURTHER 
    INFORMATION CONTACT'' at the beginning of the preamble.
        If you are an entity identified in Table 1 of this unit, you would 
    only be subject to the testing requirements contained in this proposed 
    rule if you manufacture or process any of the 47 chemical substances 
    that are listed in Table 2 of this unit.
    
    
           Table 2.--List of Chemical Substances Proposed for Testing
    ------------------------------------------------------------------------
                     CAS No.                         Chemical substance
    ------------------------------------------------------------------------
    60-29-7                                    Ethyl ether
    74-96-4                                     Ethyl bromide
    75-05-8                                    Acetonitrile
    75-15-0                                    Carbon disulfide
    75-35-4                                    Vinylidene chloride
    77-73-6                                     Dicyclopentadiene
    77-78-1                                     Dimethyl sulfate
    78-59-1                                     Isophorone
    78-83-1                                     Isobutyl alcohol
    78-87-5                                     Propylene dichloride
    78-92-2                                    sec-Butyl alcohol
    79-20-9                                     Methyl acetate
    79-46-9                                     2-Nitropropane
    91-20-3                                     Naphthalene
    
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    92-52-4                                     Biphenyl
    95-49-8                                     o-Chlorotoluene
    95-50-1                                    o-Dichlorobenzene
    97-77-8                                     Disulfiram
    98-29-3                                     tert-Butylcatechol
    99-99-0                                    p-Nitrotoluene
    100-00-5                                   p-Nitrochlorobenzene
    100-01-6                                   p-Nitroaniline
    100-44-7                                    Benzyl chloride
    106-42-3                                    p-Xylene
    106-46-7                                    p-Dichlorobenzene
    107-06-2                                    Ethylene dichloride
    107-31-3                                    Methyl formate
    108-03-2                                    1-Nitropropane
    108-90-7                                    Chlorobenzene
    108-93-0                                    Cyclohexanol
    109-66-0                                    Pentane
    109-99-9                                    Tetrahydrofuran
    110-12-3                                    Methyl isoamyl ketone
    111-84-2                                    Nonane
    120-80-9                                    Catechol
    121-69-7                                    Dimethylaniline
    122-39-4                                    Diphenylamine
    123-42-2                                    Diacetone alcohol
    126-99-8                                    beta-Chloroprene
    127-19-5                                    Dimethyl acetamide
    142-82-5                                   n-Heptane
    150-76-5                                    p-Methoxyphenol
    528-29-0                                   o-Dinitrobenzene
    628-63-7                                    n-Amyl acetate
    768-52-5                                   N-Isopropylaniline
    25013-15-4                                  Vinyl toluene
    34590-94-8                                  Dipropylene glycol methyl
                                                ether
    ------------------------------------------------------------------------
    
    
    B. How Can I Get Additional Information or Copies of This Document or 
    Other Documents?
    
        1. Electronically. You may obtain electronic copies of this 
    document and other documents from the EPA Internet EPA Home Page at 
    http://www.epa.gov/. On the Home Page select ``Law and Regulations'' 
    and then look up the entry for this document under ``Federal Register--
    Environmental Documents.'' You can also go directly to the Federal 
    Register listings at http://www.epa.gov/fedrgstr/.
        2. In person . The official record for this proposed rule, which 
    includes the public version, has been established under docket control 
    number OPPTS-42196. The official record consists of the documents 
    referenced in this preamble (see Unit VIII. of this preamble), as well 
    as the public comments that will be received during the comment period, 
    and other information related to this rulemaking, including information 
    claimed as Confidential Business Information (CBI). This official 
    record includes the documents that are physically located in the 
    docket, as well as all documents that are referenced in those 
    documents. The public version of the offical record does not include 
    any information claimed as CBI. The public version of the official 
    record, which includes printed, paper versions of any electronic 
    comments that may be submitted as described in Unit I.C. and D. of this 
    preamble, is available for inspection in the TSCA Nonconfidential 
    Information Center, Rm. NE B-607, 401 M St., SW., Washington, DC. The 
    Center is open from 12 noon to 4 p.m., Monday through Friday, excluding 
    legal holidays. The telephone number of the Center is (202) 260-7099.
    
    C. How and To Whom Do I Submit Comments?
    
        You may submit comments through the mail, in person, or 
    electronically. To ensure proper receipt by EPA, your comments must 
    identify docket control number OPPTS-42196 in the subject line on the 
    first page of your response.
        1. By mail. Submit comments to: Document Control Office (7407), 
    Office of Pollution Prevention and Toxics, Environmental Protection 
    Agency, 401 M St., SW., East Tower, Rm. G-099, Washington, DC 20460.
        2. In person or by courier. Deliver comments to: Document Control 
    Office, Office of Pollution Prevention and Toxics, Environmental 
    Protection Agency, 401 M St., SW., East Tower, Rm. G-099, Washington, 
    DC. The telephone number for the OPPT Document Control Office is (202) 
    260-7093.
        3. Electronically. Submit your comments electronically by e-mail 
    to: oppt.ncic@epa.gov, or you may mail or deliver your computer disk to 
    the addresses identified in Units I.C.1. or 2. of this preamble. Do not 
    submit any information electronically that you consider to be CBI. 
    Submit comments as an ASCII file, avoiding the use of special 
    characters and any form of encryption. Comments will also be accepted 
    on standard disks in WordPerfect 5.1/6.1 or ASCII file format. All 
    copies of electronic comments must be identified by docket control 
    number OPPTS-42196. Electronic comments may be filed online at many 
    Federal Depository Libraries.
    
    D. How Should I Handle CBI Information That I Want To Submit To The 
    Agency?
    
        Do not submit any information electronically that you consider to 
    be CBI. You may claim information that you submit in response to this 
    document as CBI by marking any part or all of that information as CBI. 
    Information so marked will not be disclosed except in accordance with 
    procedures set forth in 40 CFR part 2. In addition to one complete 
    version of the comments that include any information claimed as CBI, a 
    copy of the comments that does not contain the information claimed as 
    CBI must be submitted for inclusion in the public version of the 
    official record. Information not marked confidential will be included 
    in the public version of the official record by EPA without prior 
    notice. If you have any questions about CBI or the procedures for 
    claiming CBI, consult the technical person identified in ``FOR FURTHER 
    INFORMATION CONTACT''at the beginning of this preamble.
    
    E. Can I Request An Opportunity To Present Oral Comments To The Agency?
    
        You may submit a request for an opportunity to present oral 
    comments. This request must be in writing. If such a request is 
    received on or before July 9, 1999, EPA will hold a public meeting on 
    this proposed rule in Washington, DC. This written request must be 
    submitted to the address provided in Unit I.C. of this preamble. If 
    such a request is received, EPA will announce the scheduling of the 
    public meeting in a subsequent Federal Register document. If a public 
    meeting is announced, and if you are interested in attending or 
    presenting oral and/or written comments at the public meeting, you 
    should follow the instructions provided in the subsequent Federal 
    Register document announcing the public meeting.
    
    F. What Should I Consider as I Prepare My Comments For EPA?
    
        We invite you to provide your views on the various options we 
    propose, new approaches we have not considered, the potential impacts 
    of the various options (including possible unintended consequences), 
    and any data or information that you would like the Agency to consider 
    during the development of the final rule. You may find the following 
    suggestions helpful for preparing your comments:
          Explain your views as clearly as possible.
          Describe any assumptions that you used.
          Provide copies of any technical information and/or data 
    you used that support your views.
          If you estimate potential burden or costs, explain how 
    you arrived at the estimate.
          Provide specific examples to illustrate your concerns.
          Offer alternative ways to improve the rule or collection 
    activity.
    
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          Make sure to submit your comments by the deadline in this 
    document.
          At the beginning of your comments, be sure to properly 
    identify the document you are commenting on. To ensure proper receipt 
    by EPA, your comments must identify the docket control number assigned 
    to this action in the subject line on the first page of your response. 
    You may also provide the name, date, and Federal Register citation.
    
    G. Are There Issues On Which EPA Is Particularly Interested In 
    Receiving Comment?
    
        EPA invites comment on any aspect of this proposed rule. EPA is 
    particularly interested in specific comments on the approach discussed 
    in Unit V.C. of this preamble, entitled ``Would I Be Required To Test 
    Under This Rule?''
    
    II. Authority
    
        This document proposes a test rule under TSCA section 4(a) (15 
    U.S.C 2603(a)) that would require an in vitro dermal absorption rate 
    test for 47 of the chemical substances designated by the ITC for this 
    testing.
        Section 2(b)(1) of TSCA (15 U.S.C. 2601(b)(1)) states that it is 
    the policy of the United States that ``adequate data should be 
    developed with respect to the effect of chemical substances and 
    mixtures on health and the environment and that the development of such 
    data should be the responsibility of those who manufacture and those 
    who process such chemical substances and mixtures [.]'' To implement 
    this policy, TSCA section 4(a) mandates that EPA require by rule that 
    manufacturers and processors of chemical substances and mixtures 
    conduct testing if the Administrator finds that:
    
        (1)(A)(i) the manufacture, distribution in commerce, processing, 
    use, or disposal of a chemical substance or mixture, or that any 
    combination of such activities, may present an unreasonable risk of 
    injury to health or the environment,
        (ii) there are insufficient data and experience upon which the 
    effects of such manufacture, distribution in commerce, processing, 
    use, or disposal of such substance or mixture or of any combination 
    of such activities on health or the environment can reasonably be 
    determined or predicted, and
        (iii) testing of such substance or mixture with respect to such 
    effects is necessary to develop such data; or
        (B)(i) a chemical substance or mixture is or will be produced in 
    substantial quantities, and (I) it enters or may reasonably be 
    anticipated to enter the environment in substantial quantities or 
    (II) there is or may be significant or substantial human exposure to 
    such substance or mixture,
        (ii) there are insufficient data and experience upon which the 
    effects of the manufacture, distribution in commerce, processing, 
    use, or disposal of such substance or mixture or of any combination 
    of such activities on health or the environment can reasonably be 
    determined or predicted, and
        (iii) testing of such substance or mixture with respect to such 
    effects is necessary to develop such data [.]
    
        If EPA makes these findings for a chemical substance or mixture, 
    the Administrator must require by rule that testing be conducted on 
    that chemical substance or mixture. The purpose of the testing would be 
    to develop data about the substance or mixture's health and 
    environmental effects for which there is an insufficiency of data and 
    experience, and which are relevant to a determination that the 
    manufacture, distribution in commerce, processing, use, or disposal of 
    the substance or mixture, or any combination of such activities, does 
    or does not present an unreasonable risk of injury to health or the 
    environment.
        Once the Administrator has made a finding under TSCA section 
    4(a)(1)(A)(i) (i.e., a finding that a chemical substance may present an 
    unreasonable risk of injury to health or the environment) or a finding 
    under TSCA section 4(a)(1)(B)(i) (i.e., a finding that a chemical 
    substance is or will be produced in substantial quantities and either 
    it may enter the environment in substantial quantities or there may be 
    significant or substantial human exposure to the chemical substance), 
    EPA may require any type of health or environmental effects testing 
    necessary to address unanswered questions about the effects of the 
    chemical substance. EPA need not limit the scope of testing required to 
    the factual basis for the TSCA section 4(a)(1)(A)(i) or (B)(i) 
    findings, as long as EPA also finds that there are insufficient data 
    and experience upon which the effects of the manufacture, distribution 
    in commerce, processing, use, or disposal of such substance or mixture 
    or of any combination of such activities on health or the environment 
    can reasonably be determined or predicted, and that testing is 
    necessary to develop such data. This approach is explained in more 
    detail in EPA's statement of policy for making findings under TSCA 
    section 4(a)(1)(B) (frequently described as the ``B'' policy) in the 
    Federal Register of May 14, 1993 (58 FR 28736, 28738-28739).
        In this proposed rule, EPA intends to use its broad TSCA section 
    4(a) authority to obtain dermal absorption rate data necessary to 
    support OSHA's development of ``skin designations'' (see Unit III.C. of 
    this preamble) for the 47 chemical substances included in the proposed 
    rule. EPA has made preliminary findings for these chemicals under TSCA 
    section 4(a)(1)(B) that: They are produced in substantial quantities; 
    there is or may be substantial human exposure to them; existing data 
    are insufficient to determine or predict their health effects; and 
    testing is necessary to develop such data.
        Under TSCA section 10(b), EPA is responsible, through an 
    interagency committee, for collecting data and disseminating the data 
    to other Federal agencies, such as OSHA, as the Agency is proposing in 
    this document. EPA has used its TSCA section 4(a) authority in the past 
    to support regulatory programs of other EPA offices as well as other 
    Federal agencies needing health and/or environmental effects test data. 
    See, e.g., the final test rule for the Office of Water Chemicals (58 FR 
    59667, 59673 November 10, 1993).
    
    III. Background
    
    A. Why Is EPA Proposing To Take This Action?
    
        Under TSCA section 4(e)(1), the ITC is responsible for recommending 
    chemical substances and mixtures to the EPA Administrator for priority 
    testing consideration. The chemical substances and mixtures so 
    designated by the ITC comprise a list called the Priority Testing List. 
    OSHA nominated 658 chemical substances and mixtures for ITC review in 
    September 1991. The results of the ITC's review were published in the 
    Federal Register issues of May 5, 1993 (58 FR 26898, 26900) and July 
    16, 1993 (58 FR 38490, 38492-38493). OSHA requested that the ITC assess 
    the availability of data relevant to dermal absorption for these 
    chemical substances and mixtures and determine the need for further 
    testing (58 FR 26898, 26900, May 5, 1993). OSHA indicated to the ITC 
    that it needed quantitative measures of dermal absorption to evaluate 
    the potential hazard of these chemicals to workers (58 FR 38490, 38492, 
    July 16, 1993). These quantitative measures are expressed as the dermal 
    absorption rate for a particular chemical (59 FR 35720, 35725, July 13, 
    1994).
        In its 31st, 32nd, and 35th ITC Reports to the EPA Administrator 
    (58 FR 26898, May 5, 1993; 58 FR 38490, July 16, 1993; and 59 FR 67596, 
    December 29, 1994, respectively), the ITC designated for in vitro 
    dermal absorption rate testing a total of 83 of the chemical substances 
    nominated by OSHA. In reducing OSHA's list of 658 chemicals to 83 
    chemicals, the ITC
    
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    grouped the nominated chemicals into categories as a means of 
    prioritizing the chemicals for consideration. Chemicals that were 
    assigned to categories such as polymers, pesticides, and 
    chloroflurocarbons were eliminated from consideration by the ITC. They 
    were eliminated because, among other reasons, they are regulated under 
    other Federal authorities or because EPA, under TSCA, does not have the 
    authority to require the testing of certain chemicals (58 FR 26898, 
    26900-26902 and 58 FR 38490, 38493). The remaining chemicals were then 
    grouped by production volume, and literature searches were performed.
        The ITC performed searches for data relating to the chemicals on 
    the following data bases: RTECS (Registry of Toxic Effects of Chemical 
    Substances), TOXLINE (TOXicology information onLINE), MEDLINE (MEDlars 
    onLINE), TOXLIT (TOXicology LITerature from special sources), CECATS 
    (OPPT/Risk Assessment Division/Chemical Screening Branch's Existing 
    Chemical Assessment Tracking System), TSCATS (Toxic Substances Control 
    Act Test Submissions), and INDEX MEDICUS. The search strategy was 
    designed to identify any toxicological tests that used the dermal route 
    of exposure. The information from the searches was collected and the 
    chemicals were subcategorized based on the number of postings (58 FR 
    38490, 38493).
        The 83 chemicals designated by the ITC were identified as follows: 
    The ITC first ascertained those chemicals having no dermal information 
    postings in any of the data bases searched, and, in its 31st ITC 
    Report, the ITC designated this group of 24 chemicals for priority 
    testing consideration (58 FR 26898, 26900). A second group of chemicals 
    with limited dermal toxicity or dermal absorption data (as determined 
    by the searches described in this unit) from which dermal absorption 
    rate could not be estimated was then identified by the ITC, which 
    designated this group of 34 chemicals in its 32nd ITC Report (Ref. 1) 
    (58 FR 38490, 38492, 38494). Another 25 chemicals were designated in 
    the 35th ITC Report, after the ITC reviewed the dermal data of 63 high 
    production volume chemicals with slightly larger information bases (59 
    FR 67596, 67598). These data were insufficient to estimate dermal 
    absorption rate because dermal absorption rate could not be calculated 
    on the basis of the dermal absorption data which were available to the 
    ITC.
        The ITC then reviewed data from TSCA section 8(a) and 8(d) rules 
    which were promulgated by EPA for these 83 chemical substances included 
    in the 31st, 32nd, and 35th ITC Reports (40 CFR 712.30(e) (58 FR 68311, 
    December 27, 1993; 59 FR 5956, February 9, 1994; 60 FR 34879, July 5, 
    1995)). These rules required the reporting to EPA of certain 
    production, use and exposure-related information, and unpublished 
    health and safety data concerning these 83 chemicals.
        In reviewing the available data relating to these 83 chemicals, the 
    ITC determined that the dermal absorption rate data for methyl 
    methacrylate (Ref. 2), diethyl phthalate (Ref. 3), and cyclohexanone 
    (Ref. 4) would meet OSHA's data needs for the chemicals (59 FR 35720, 
    35722, July 13, 1994; 60 FR 42982, 42985, August 17, 1995). 
    Accordingly, the ITC withdrew its designation for these 3 chemicals: 
    Methyl methacrylate and diethyl phthalate in the 34th ITC Report (59 FR 
    35720, 35725, July 13, 1994), and cyclohexanone in the 36th ITC Report 
    (60 FR 42982, 42987, August 17, 1995).
        Eighty of the chemical substances nominated by OSHA are thus 
    currently designated by the ITC for in vitro dermal absorption rate 
    testing under TSCA. In the Federal Register notices containing the 
    31st, 32nd, and 35th ITC Reports, EPA additionally solicited proposals 
    for TSCA section 4 enforceable consent agreements (ECAs) for dermal 
    absorption rate testing of the 80 chemical substances. EPA received no 
    proposals for ECAs for dermal absorption rate testing in response to 
    these solicitations.
        On April 3, 1996 (61 FR 14773), EPA again solicited interested 
    parties to submit proposals for ECAs. On June 26, 1996, EPA received a 
    proposal for the development of an ECA for tert-butyl alcohol from the 
    ARCO Chemical Company (ARCO). On March 26, 1998, EPA received a study 
    entitled ``[14C]-t-Butyl Alcohol: Topical Application: 
    Dermal Absorption Study in the Male Rat,'' from ARCO (Ref. 5). This 
    study was reviewed and found acceptable as a means of determining the 
    dermal absorption rate for tert-butyl alcohol (Ref. 6). Accordingly, 
    this action does not propose testing of tert-butyl alcohol.
        In this action, EPA is proposing in vitro dermal absorption rate 
    testing of 47 chemical substances of interest to OSHA. These chemical 
    substances are listed in Table 2 of Unit I.A. of this preamble, 
    entitled ``List of Chemical Substances Proposed for Testing,'' and in 
    Table 2 of Sec. 799.5115(i) of the proposed regulatory text, entitled 
    ``Required Testing: Chemical Substances Designated for In Vitro Dermal 
    Absorption Rate Testing.'' EPA has selected these 47 chemicals for 
    testing because the Agency believes that the production volumes of 
    these chemicals are higher than the production volumes of the 32 
    chemicals remaining out of the 80 chemicals currently designated by the 
    ITC. Testing of the latter chemicals for dermal absorption rate will be 
    addressed at a later date.
    
    B. How Was the Test Standard Developed For EPA's Use in This Proposed 
    Rule?
    
        In the solicitations discussed in Unit III.A. of this preamble, EPA 
    referenced an in vitro dermal absorption rate test protocol for review 
    by potential submitters in developing their proposed protocols (Ref. 
    7). The draft protocol was developed by a group of scientists from EPA 
    in conjunction with ITC member and liaison agencies (Consumer Product 
    Safety Commission (CPSC), Department of Defense (DoD), Food and Drug 
    Administration (FDA), National Institute for Occupational Safety and 
    Health (NIOSH), and OSHA) and consisted of the methods of Bronaugh and 
    Collier (Ref. 7). EPA received public comments on the proposed protocol 
    and entered them, along with the protocol itself, into the dockets for 
    the 31st, 32nd, and 35th ITC Reports, as appropriate (docket control 
    numbers OPPTS-41038, OPPTS-41039, and OPPTS-41042, respectively). In 
    addition, the Chemical Manufacturers Association (CMA) submitted a 
    proposed protocol outlining an alternative method (Ref. 8). Scientists 
    from EPA and other Federal agencies represented on the ITC (including 
    OSHA) reviewed the public comments and the CMA proposal. Based on their 
    review of the Bronaugh and Collier protocol, public comments, and the 
    CMA proposal, EPA and ITC scientists developed the in vitro dermal 
    absorption rate test method which is the test standard used in this 
    proposed rule.
    
    C. How Will The Data Developed Under This Test Rule Be Used?
    
        This proposed rule would require the development of quantitative 
    measures of dermal absorption rate to assist in evaluating the 
    potential contribution of dermal absorption of the chemical substances 
    proposed for testing to total exposures to workers from chemicals in 
    the workplace. The dermal absorption rate data obtained under this 
    testing program would be used to support OSHA's development of ``skin 
    designations'' for the chemical substances included in this proposed 
    rule.
        OSHA assigns a skin designation to a chemical if it determines that 
    cutaneous exposure (through the skin, eyes, and mucous membranes) to 
    the chemical may result in systemic toxicity. Skin
    
    [[Page 31078]]
    
    designations are used by OSHA to provide specific guidance to employers 
    concerning whether changes should be made to processes involving 
    chemical substances in order to reduce the hazard of systemic toxicity 
    from dermal absorption of these chemicals. Changes to a process might 
    include changes in engineering controls or changes in the use or type 
    of personal protective equipment. Skin designations alert industrial 
    hygienists, employers, and workers to potential adverse health effects 
    resulting from dermal exposure to chemicals in the workplace.
        The information that would be developed under this test rule would 
    not only support OSHA's activities, but also would support chemical 
    risk assessment activities at EPA as well as at other Federal agencies. 
    In particular, these data would provide input for chemical risk 
    assessments involving environmental exposure scenarios which include 
    intentional or incidental skin contact.
    
    IV. EPA Findings
    
    A. What Is The Basis For EPA's Proposal To Test These Chemical 
    Substances?
    
        As indicated in Unit II. of this preamble, in order to develop a 
    rule under TSCA section 4(a) requiring the testing of chemical 
    substances or mixtures, EPA must make certain findings for those 
    chemicals regarding either:
        1. Hazard (TSCA section 4(a)(1)(A)(i)); or
        2. Production and either chemical release or human exposure (TSCA 
    section 4(a)(1)(B)(i)).
    EPA is proposing to require testing of the chemical substances included 
    in this test rule based on its findings under TSCA section 
    4(a)(1)(B)(i) relating to ``substantial'' production and ``substantial 
    human exposure,'' as well as findings under TSCA sections 
    4(a)(1)(B)(ii) and (iii).
        In EPA's ``B'' policy, discussed in Unit II. of this preamble, 
    ``substantial'' production of a chemical substance or mixture is 
    generally interpreted to be aggregate production (including import) 
    volume equaling or exceeding one million pounds (lbs) per year of that 
    chemical substance or mixture (58 FR 28736, 28746, May 14, 1993). The 
    ``B'' policy sets out the numeric threshold for ``substantial human 
    exposure'' of workers to a chemical substance or mixture of 1,000 
    workers annually being exposed to that chemical substance or mixture. 
    Id. See EPA's ``B'' policy (58 FR 28736, May 14, 1993) for further 
    discussion on how EPA makes decisions under TSCA section 4(a)(1)(B)(i).
        EPA has found preliminarily that, under TSCA section 4(a)(1)(B)(i), 
    each of the 47 chemical substances proposed for dermal absorption rate 
    testing is produced in ``substantial quantities'' and there is or may 
    be ``substantial human exposure'' to each chemical substance. In 
    addition, under TSCA section 4(a)(1)(B)(ii), EPA believes that there 
    are insufficient data and experience to reasonably determine or predict 
    the effects of the manufacturing, processing, or use of these chemical 
    substances, or of any combination of such activities, on human health. 
    In particular, as discussed in Unit IV.D. of this preamble, EPA has 
    determined that there are insufficient data relating to dermal 
    absorption rate resulting from human exposure to these chemicals. EPA 
    also finds that testing the substances identified in this document is 
    necessary to develop such data (TSCA section 4(a)(1)(B)(iii)). EPA has 
    not identified any ``additional factors'' as discussed in the ``B'' 
    policy (58 FR 28736, 28746, May 14, 1993) to cause the Agency to use 
    decisionmaking criteria other than those described in the policy.
        The specific chemical substances included in this proposed test 
    rule are listed in Table 2 of Unit I.A. of this preamble, and in 
    Sec. 799.5115(i) of the proposed regulatory text.
    
    B. Are These Chemical Substances Produced in Substantial Quantities?
    
        Each of the chemical substances included in this proposal is 
    produced in an amount equal to or greater than one million lbs per year 
    (Ref. 9), based on information gathered pursuant to the 1994 TSCA 
    section 8(a) Inventory Update Rule (40 CFR part 710) and contained in 
    the TSCA Chemical Update System. Their production volumes range from 
    over one million to well over one billion lbs annually. Assuming the 
    continued accuracy of these figures, EPA believes that these annual 
    production volumes are ``substantial'' as that term is used with 
    reference to production in TSCA section 4(a)(1)(B)(i). See 58 FR 28736, 
    28746, May 14, 1993.
    
    C. Are a Substantial Number Of Workers Exposed To These Chemicals?
    
        EPA finds that the manufacturing, processing, and use of the 
    chemical substances included in this document result or may result in 
    exposure of a substantial number of workers. Table 3, entitled 
    ``Exposure Information for Chemical Substances Included in This 
    Proposed Test Rule,'' in Unit IV.C. of this preamble contains an 
    estimate of the actual and potential worker exposure to these chemical 
    substances (Ref. 10). These chemical substances are used in a wide 
    variety of applications as industrial solvents, which result in 
    potential exposures of workers as described in the exposure support 
    document for this proposed rule (Ref. 10). EPA believes that the 
    exposure to each chemical substance of 1,000 workers or more (Table 3 
    of this unit) is or may be ``substantial'' as that term is used with 
    reference to ``human exposure'' in TSCA section 4(a)(1)(B)(i). See 58 
    FR 28376, 28746, May 14, 1993.
    
    
     Table 3.--Exposure Information for Chemical Substances Included in This
                               Proposed Test Rule
    ------------------------------------------------------------------------
                                                           Number of workers
                 CAS No.                Chemical name         exposed\1\
    ------------------------------------------------------------------------
    60-29-7                          Ethyl ether           272,746
    74-96-4                          Ethyl bromide         12,285
    75-05-8                          Acetonitrile          31,341
    75-15-0                           Carbon disulfide    45,761
    75-35-4                          Vinylidene chloride  2,679
    77-73-6                           Dicyclopentadiene    6,247
    77-78-1                          Dimethyl sulfate     10,482
    78-59-1                          Isophorone           47,097
    78-83-1                          Isobutyl alcohol     256,975
    78-87-5                          Propylene            2,944
                                      dichloride
    78-92-2                          sec-Butyl alcohol    126,200
    79-20-9                          Methyl acetate       20,455
    79-46-9                          2-Nitropropane        9,817
    91-20-3                          Naphthalene          112,695
    92-52-4                          Biphenyl             32,000
    
    [[Page 31079]]
    
     
    95-49-8                          o-Chlorotoluene      11,617
    95-50-1                           o-Dichlorobenzene   92,248
    97-77-8                           Disulfiram           53,525
    98-29-3                          tert-Butylcatechol    27,528
    99-99-0                           p-Nitrotoluene       4,354
    100-00-5                          p-                   2,949
                                      Nitrochlorobenzene
    100-01-6                          p-Nitroaniline       1,448
    100-44-7                          Benzyl chloride      41,075
    106-42-3                          p-Xylene             20,367
    106-46-7                         p-Dichlorobenzene     33,980
    107-06-2                          Ethylene             83,245
                                      dichloride
    107-31-3                          Methyl formate       7,739
    108-03-2                          1-Nitropropane       21,535
    108-90-7                          Chlorobenzene        18,049
    108-93-0                          Cyclohexanol         112,366
    109-66-0                          Pentane              38,464
    109-99-9                          Tetrahydrofuran      356,041
    110-12-3                          Methyl isoamyl       18,835
                                      ketone
    111-84-2                          Nonane               7,277
    120-80-9                          Catechol             13,517
    121-69-7                          Dimethylaniline      30,479
    122-39-4                          Diphenylamine        155,673
    123-42-2                         Diacetone alcohol     264,660
    126-99-8                         beta-Chloroprene      17,752
    127-19-5                          Dimethyl acetamide   28,944
    142-82-5                          n-Heptane            449,487
    150-76-5                         p-Methoxyphenol       250,088
    528-29-0                          o-Dinitrobenzene     1,358
    628-63-7                         n-Amyl acetate        265,435
    768-52-5                         N-Isopropylaniline   >1,000\2\
    25013-15-4                        Vinyl toluene        25,353
    34590-94-8                        Dipropylene glycol   210,735
                                      methyl ether
    ------------------------------------------------------------------------
    \1\National Occupational Exposure Survey (NOES) conducted by the NIOSH
      (1981-1983), unless otherwise indicated. These data are the most
      recent available to the Agency (Ref. 10).
    \2\Not listed in NOES data base. The exposure analysis for this chemical
      is attached to Reference 10.
    
    
    D. Do Sufficient Data Exist For These Chemical Substances?
    
        As discussed in this preamble, dermal absorption rate is an 
    important factor in ascertaining the effects of the 47 chemicals in 
    this proposed rule on human health. EPA has determined that there are 
    no dermal absorption rate data for the chemicals in this proposed rule 
    and, therefore, existing data are insufficient to reasonably determine 
    or predict the human health effects relating to dermal absorption rate 
    that result from manufacturing, processing, or use of the subject 
    chemical substances. This finding is based on the review and analysis 
    of relevant data by the ITC (which included EPA participation), as 
    described in Unit III.A. of this preamble.
    
    E. Is Testing Necessary For These Chemical Substances?
    
        EPA believes that the proposed testing of the 47 subject chemical 
    substances is necessary to develop dermal absorption rate data. This 
    testing is needed to determine if the manufacturing, processing, or use 
    of these chemical substances presents an unreasonable risk of injury to 
    human health.
    
    V. Proposed Rule
    
    A. How Would the Studies Proposed Under This Test Rule Be Conducted?
    
        EPA is proposing specific testing and reporting requirements for 
    the chemical substances specified in Table 2 in Sec. 799.5115(i) of the 
    proposed regulatory text according to the in vitro dermal absorption 
    rate test standard set forth at Sec. 799.5115(h) of the proposed 
    regulatory text.
        The test standard that would be required under this rule was 
    developed as described in Unit III.B. of this preamble. This standard 
    describes the procedures for measuring a permeability constant (Kp) and 
    a short-term absorption rate for chemicals in liquid form. Measurement 
    of short-term absorption rates is only required when a Kp cannot be 
    obtained using this test standard. For most chemicals, a Kp is useful 
    in estimating skin permeation. However, for ``harsh'' chemicals, i.e., 
    those that may damage the skin more severely with prolonged contact, it 
    is more appropriate to obtain a short-term absorption rate measurement.
        This test standard utilizes established in vitro diffusion cell 
    techniques that allow absorption rate studies to be conducted using 
    human skin (see the proposed regulatory text at Sec. 799.5115(h)). The 
    in vitro approach was chosen for practical considerations because it is 
    efficient in terms of labor and materials and can be performed easily 
    by a variety of laboratories. In addition, in vitro diffusion cell 
    studies are necessary for measuring a Kp (Ref. 7).
        The in vitro dermal absorption rate test standard allows use of 
    cadaver skin and static diffusion cells to maintain the viability of 
    the skin, thus more closely simulating in vivo conditions. This test 
    method also requires the use of radiolabelled chemical substances 
    unless the test sponsor can demonstrate that alternative, non-
    radiolabelled methods provide sensitivity sufficient to detect the 
    parent chemical (and its major metabolites in those cases in which skin 
    viability is maintained). The first six parameters that are discussed 
    (choice of membrane, preparation of membrane, diffusion cell design, 
    temperature, testing hydrophobic chemicals, and vehicle) are similar 
    for determination of either of the two percutaneous absorption rate 
    values. In
    
    [[Page 31080]]
    
    contrast, the remaining two parameters (i.e., dose and study duration) 
    are different for the two percutaneous absorption rate values.
        Testing under this proposed rule must be conducted in accordance 
    with TSCA Good Laboratory Practice (GLP) Standards (40 CFR part 792).
    
    B. What Substances Would Be Tested Under This Rule?
    
        EPA is proposing that the chemical substances listed in Table 2 in 
    Sec. 799.5115(i) of the proposed regulatory text be tested at a purity 
    of at least 99%.
    
    C. Would I Be Required To Test Under This Rule?
    
        Under TSCA section 4(a)(1)(B), EPA has made preliminary findings 
    that there are insufficient data and experience to reasonably determine 
    or predict health effects resulting from the manufacturing, processing, 
    or use of the chemical substances listed in this proposed rule. As a 
    result, under TSCA section 4(b)(3)(B), manufacturers and processors of 
    these substances would be subject to the rule with regard to those 
    listed chemicals which they manufacture or process.
        1. Would I be subject to this rule? You would be subject to this 
    rule and may be required to test if you manufacture (which is defined 
    by statute to include import) or process, or intend to manufacture or 
    process, one or more chemical substances listed in this proposed rule 
    during the time period discussed in Unit V.C.2. of this preamble, 
    entitled ``When would my manufacturing or processing (or my intent to 
    do so) cause me to be subject to this rule?'' However, if you do not 
    know or cannot reasonably ascertain that you manufacture or process a 
    listed test substance (based on all information in your possession or 
    control, as well as all information that a reasonable person similarly 
    situated might be expected to possess, control, or know, or could 
    obtain without unreasonable burden), you would not be subject to the 
    rule.
        2. When would my manufacturing or processing (or my intent to do 
    so) cause me to be subject to this rule? You would be subject to this 
    rule if you manufacture or process, or intend to manufacture or 
    process, a substance listed in the rule at any time from the effective 
    date of the final test rule to the end of the test data reimbursement 
    period.
        The term reimbursement period is defined at 40 CFR 791.3(h) and may 
    vary in length for each substance to be tested under a final TSCA 
    section 4(a) test rule, depending on what testing is required and when 
    testing is completed. See Unit V.C.4. of this preamble, entitled ``How 
    do the reimbursement procedures work?''
        3. Would I be required to test if I were subject to the rule? It 
    depends on the nature of your activities. All persons who would be 
    subject to this TSCA section 4(a) test rule, which incorporates EPA's 
    generic procedures applicable to TSCA section 4(a) test rules 
    (contained within 40 CFR part 790), would fall into one of two groups, 
    designated here as Tier 1 and Tier 2. Persons in Tier 1 (those who 
    would have to initially comply with the rule) must either: Submit to 
    EPA letters of intent to conduct testing, conduct this testing, and 
    submit the test data to EPA or apply to and obtain from EPA exemptions 
    from testing. Persons in Tier 2 (those who would not have to initially 
    comply with the rule) need not take any action unless they are notified 
    by EPA that they are required to do so, as described in Unit V.C.3.d. 
    of this preamble, entitled ``What would my obligations be if I were in 
    Tier 2?'' Note that persons in Tier 1 who obtain exemptions and persons 
    in Tier 2 would nonetheless be subject to providing reimbursement to 
    persons who do actually conduct the testing, as described in Unit 
    V.C.4. of this preamble, entitled ``How do the reimbursement procedures 
    work?''
        a. Who would be in Tier 1 and Tier 2? All persons subject to this 
    rule would be considered to be in Tier 1 unless they fall within Tier 
    2. The following table describes who is in Tier 1 and Tier 2.
    
    
      Table 4.-- Persons Subject to the Rule: Persons in Tier 1 and Tier 2
    ------------------------------------------------------------------------
     Tier 1 (Persons initially required to    Tier 2 (Persons not initially
                    comply)                        required to comply)
    ------------------------------------------------------------------------
    Persons that manufacture (as     Persons that
     defined at TSCA section 3(7)), or        manufacture (as defined at
     intend to manufacture, a test rule       TSCA section 3(7)) or intend
     substance who are not listed under       to manufacture a test rule
     Tier 2                                   substance solely as one or
                                              more of the following:
                                             --As a byproduct (as defined at
                                              40 CFR 791.3(c));
                                             --As an impurity (as defined at
                                              40 CFR 790.3);
                                             --As a naturally occurring
                                              substance (as defined at 40
                                              CFR 710.4(b));
                                             --As a non-isolated
                                              intermediate (as defined at 40
                                              CFR 704.3);
                                             --As a component of a Class 2
                                              substance (as described at 40
                                              CFR 720.45(a)(1)(i));
                                             --In amounts of less than 500
                                              kilograms (kg) (1,100 lbs)
                                              annually (as described at 40
                                              CFR 790.42(a)(4)); or
                                             --In small quantities solely
                                              for research and development
                                              (as described at 40 CFR
                                              790.42(a)(5)).
                                             Persons that process
                                              (as defined at TSCA section
                                              3(10)) or intend to process a
                                              test rule substance (see 40
                                              CFR 790.42(a)(2))
    ------------------------------------------------------------------------
    
    
        b. When would it be appropriate for a person in Tier 1 to apply for 
    an exemption rather than to submit a letter of intent to conduct 
    testing? You may apply for an exemption if you believe that the 
    required testing will be performed by another person (or a consortium 
    of persons formed under TSCA section 4(b)(3)(A)) in Tier 1. You can 
    find procedures relating to exemptions in 40 CFR 790.80 through 790.99, 
    and in the proposed regulatory text at Sec. 799.5115(c)(2), (c)(5), and 
    (c)(7). In this rule, EPA would not require equivalence data (i.e., 
    data demonstrating that your substance is equivalent to the substance 
    actually being tested) as a condition for approval of your exemption. 
    EPA is interested in evaluating the effects attributable to each listed 
    substance itself and has specified almost pure substances for testing.
        c. What would happen if I were in Tier 1 and I submitted an 
    exemption application? EPA believes that requiring the collection of 
    duplicative data is unnecessarily burdensome. As a result, if EPA has 
    received a letter of intent to test from another source or has received 
    (or expects to receive) the test data that would be required under this 
    rule, the Agency would conditionally approve your exemption application 
    under 40 CFR 790.87. The Agency would
    
    [[Page 31081]]
    
    terminate conditional exemptions, if a problem occurs with the 
    initiation, conduct, or completion of the required testing or the 
    submission of the required data to EPA. EPA may then require you to 
    submit a notice of intent to test or an exemption application. See 40 
    CFR 790.93 and the proposed regulatory text at Sec. 799.5115(c)(6). 
    Persons in Tier 1 who obtain exemptions and persons in Tier 2 would 
    nonetheless be subject to providing reimbursement to persons who do 
    actually conduct the testing, as described in Unit V.C.4. of this 
    preamble, entitled ``How do the reimbursement procedures work?.''
        d. What would my obligations be if I were in Tier 2? If you are in 
    Tier 2, you would be subject to the rule and you would be responsible 
    for providing reimbursement to persons in Tier 1, as described in Unit 
    V.C.4. of this preamble. You are considered to have an automatic 
    conditional exemption. You would not need to take any action unless you 
    are notified by EPA that you are required to do so.
        If a problem occurs with the initiation, conduct, or completion of 
    the required testing, or the submission of the required data to EPA, 
    the Agency may require you to submit a notice of intent to test or an 
    exemption application. See 40 CFR 790.93 and the proposed regulatory 
    text at Sec. 799.5115(c)(6).
        In addition, you would need to submit a notice of intent to test or 
    an exemption application if:
        i. No manufacturer in Tier 1 has notified EPA of its intent to 
    conduct testing and
        ii. EPA has published a Federal Register document directing all 
    persons in Tier 2 to submit to EPA letters of intent to conduct testing 
    or exemption applications. See 40 CFR 790.48(b) and the proposed 
    regulatory text at Sec. 799.5115(c)(4) and (c)(5).
    The Agency would conditionally approve an exemption application under 
    40 CFR 790.87, if EPA has received a letter of intent to test or has 
    received (or expects to receive) the test data required under this 
    rule.
         e.  How did EPA decide who would be in Tier 1 and Tier 2 and who 
    would be excluded from the rule? Under 40 CFR 790.2, EPA may establish 
    procedures applying to specific test rules that differ from the generic 
    procedures governing TSCA section 4(a) test rules in 40 CFR part 790. 
    For purposes of this proposed rule, EPA is proposing to set forth 
    certain requirements that differ from those under 40 CFR part 790.
         Under 40 CFR part 790, in TSCA section 4(a) test rules EPA 
    traditionally has treated the following persons as being in Tier 2. 
    (These rules are found at 40 CFR part 799, subparts B and D).
        Processors (40 CFR 790.42(a)(2));
        Manufacturers of less than 500 kg (1,100 lbs) per year 
    (``small-volume manufacturers'') (40 CFR 790.42(a)(4)); and
         Manufacturers of small quantities for research and 
    development (``R&D manufacturers'') (40 CFR 790.42(a)(5)).
         EPA has historically placed processors in Tier 2 because the 
    Agency ``expected that, in most cases, testing will be performed by the 
    manufacturers and that part of the cost of testing will be passed on to 
    processors through the pricing mechanism, thereby enabling them to 
    share in the costs of testing'' (50 FR 20652, 20654, May 17, 1985). In 
    addition, ``[t]here are so many processors that it would be difficult 
    to include them all in the technical decisions about the tests and in 
    the financial decisions about how to allocate the costs'' (48 FR 31786, 
    31789, July 11, 1983).
         EPA has historically placed small-volume manufacturers and R&D 
    manufacturers in Tier 2 because this type of manufacturing ``normally 
    represents a small percentage of the overall production volume [and] 
    test sponsors are not expected to expend the administrative resources 
    to recover the small proportional amounts of the testing costs from 
    these manufacturers'' (55 FR 18881, May 7, 1990).
         In this proposed test rule, EPA has reconfigured the tiers in 40 
    CFR 790.42. EPA has added the following persons to Tier 2: Byproduct 
    manufacturers; impurity manufacturers; manufacturers of naturally 
    occurring substances; manufacturers of non-isolated intermediates; and 
    manufacturers of components of Class 2 substances. The Agency took 
    administrative burden and complexity into account in determining who 
    was to be in Tier 1 in this proposed rule. EPA believes that those 
    persons in Tier 1 who would conduct testing under this rule, when 
    finalized, would generally be large chemical manufacturers who, in the 
    experience of the Agency, have traditionally conducted testing or 
    participated in testing consortia under previous TSCA section 4(a) test 
    rules.
         The Agency also believes that byproduct manufacturers, impurity 
    manufacturers, manufacturers of naturally occurring substances, 
    manufacturers of non-isolated intermediates, and manufacturers of 
    components of Class 2 substances have not themselves historically 
    participated in testing or contributed to reimbursement of those 
    persons who have conducted testing. EPA understands that these may 
    include persons for whom the marginal transaction costs involved in 
    negotiating and administering testing arrangements are deemed likely to 
    raise the expense and burden of testing to a level that is 
    disproportional to the additional benefits of including these persons 
    in Tier 1. Therefore, EPA does not believe that the likelihood of the 
    persons proposed to be added to Tier 2 actually doing the testing is 
    sufficiently high to justify burdening these persons with Tier 1 
    requirements (e.g., submitting requests for exemptions). Nevertheless, 
    these persons, along with all other persons in Tier 2, would be subject 
    to providing reimbursement to persons who do actually conduct the 
    testing, as described in Unit V.C.4. of this preamble, entitled ``How 
    do the reimbursement procedures work?''
         Section 4(b)(3)(B) of TSCA requires all manufacturers and 
    processors of a chemical substance to test that chemical substance if 
    EPA has made findings for that chemical substance, and therefore issued 
    a TSCA section 4(a) test rule requiring testing. However, practicality 
    must be a factor in determining who is subject to a particular test 
    rule. Thus, persons who do not know or cannot reasonably ascertain that 
    they are manufacturing or processing the substances subject to this 
    proposed rule, e.g., manufacturers or processors of the substances as 
    trace contaminants who are not aware of these activities, would not be 
    subject to the rule. See Unit V.C.1 of this preamble and 
    Sec. 799.5115(b)(2) of the proposed regulatory text.
         EPA is soliciting comment on who should be included in Tier 1 and 
    Tier 2. The Agency may define these categories differently in response 
    to comments received. EPA is also soliciting comment on who should not 
    be subject to the rule. The latter persons are described at Unit V.C.1 
    of this preamble and Sec. 799.5115(b)(2) of the proposed regulatory 
    text.
        f. Should EPA prioritize which persons in Tier 2 would be required 
    to perform testing? EPA is considering subdividing Tier 2 to enable the 
    Agency to prioritize which persons in Tier 2 would be required to 
    perform testing, if needed. This would involve subdividing Tier 2 into:
        i. Tier 2A. Those who manufacture, or intend to manufacture, a test 
    rule substance solely as one or more of the following: A byproduct; an 
    impurity; a naturally occurring substance; a non-isolated intermediate; 
    a component of a Class 2 substance; in amounts less than 1,100 lbs. 
    annually; or in small quantities solely for research and development.
    
    [[Page 31082]]
    
        ii. Tier 2B. Those who process, or intend to process, a test rule 
    substance.
    If the Agency needed testing from persons in Tier 2, EPA would seek 
    testing from persons in Tier 2A before proceeding to Tier 2B. EPA 
    believes that, if the Agency were to subdivide Tier 2, persons in Tier 
    2A should be required to submit letters of intent to test or exemption 
    applications before processors are called upon because testing costs 
    are traditionally passed by manufacturers along to processors.
        EPA is soliciting comment on whether this subtiering scheme should 
    be applied in the final rule.
        4. How do the reimbursement procedures work? In the past, persons 
    subject to test rules have independently worked out among themselves 
    their respective financial contributions to those persons who have 
    actually conducted the testing. However, if persons are unable to agree 
    privately on reimbursement, they may take advantage of EPA's 
    reimbursement procedures at 40 CFR part 791, promulgated under the 
    authority of TSCA section 4(c). These procedures include: The 
    opportunity for a hearing with the American Arbitration Association; 
    publication by EPA of a Federal Register document concerning the 
    request for a hearing; and the appointment of a hearing officer to 
    propose an order for fair and equitable reimbursement. The hearing 
    officer may base his or her proposed order on the production volume 
    formula set out at 40 CFR 791.48, but is not obligated to do so. Under 
    this proposed rule, amounts manufactured as impurities would be 
    included in production volume (40 CFR 791.48(b)), subject to the 
    discretion of the hearing officer (40 CFR 791.40(a)). The hearing 
    officer's proposed order may become the Agency's final order, which is 
    reviewable in Federal court (40 CFR 791.60).
    
    D. What Are the Reporting Requirements Proposed Under This Test Rule?
    
        You would be required to submit interim progress reports for each 
    test every 6 months, beginning 6 months after the effective date of the 
    final rule. You would be required to submit a final report for a 
    specific test by the deadline indicated as the number of months after 
    the effective date that would be shown in Table 2 in Sec. 799.5115(i) 
    of the proposed regulatory text.
    
    E. Would There Be Sufficient Test Facilities and Personnel To Undertake 
    the Testing in This Test Rule?
    
        EPA has conducted a study to assess the availability of test 
    facilities and personnel to handle the additional demand for testing 
    services created by TSCA section 4(a) test rules and has found that 
    test facilities and personnel would adequately accommodate the testing 
    specified in this proposed rule (Ref. 11).
    
    F. Might EPA Seek Further Testing of the Chemicals in This Proposed 
    Test Rule?
    
        If EPA determines that it needs additional data regarding any of 
    the chemical substances included in this proposed rule, the Agency 
    might seek further health and/or environmental effects testing for 
    these chemicals. Should the Agency decide to seek such additional 
    testing, EPA would initiate a separate action for this purpose.
    
    VI. Export Notification
    
        Any person who exports, or intends to export, one of the chemical 
    substances contained in this proposed rule in any form will be subject 
    to the export notification requirements in TSCA section 12(b)(1) and 40 
    CFR part 707, subpart D, but only after the final rule is issued and 
    only if the chemical is contained in the final rule. However, 
    notification of export would generally not be required for articles, as 
    provided by 40 CFR 707.60(b).
    
    VII. Materials in the Official Record
    
        The official record for this proposed rule has been established 
    under docket control number OPPTS-42196. The following is a listing of 
    the documents that have already been placed in the official record for 
    this proposed rule:
    
    A. Supporting Documentation
    
        1. Federal Register documents:
        a. Notice containing the 31st ITC Report to the EPA Administrator 
    (58 FR 26898, May 5, 1993 (FRL-4583-4)).
        b. Notice containing the TSCA section 4(a)(1)(B) Final Statement of 
    Policy (58 FR 28736, May 14, 1993 (FRL-4059-9)).
        c. Notice containing the 32nd ITC Report to the EPA Administrator 
    (58 FR 38490, July 16, 1993 (FRL-4630-2)).
        d. TSCA Sections 8(a) and 8(d) Final Rules for Chemicals Contained 
    in the 31st ITC Report to the EPA Administrator (58 FR 68311, December 
    27, 1993 (FRL-4644-1)).
        e. TSCA Sections 8(a) and 8(d) Final Rules for Chemicals Contained 
    in the 32nd ITC Report to the EPA Administrator (59 FR 5956, February 
    9, 1994 (FRL-4745-5)).
        f. Notice containing the 34th ITC Report to the EPA Administrator 
    (59 FR 35720, July 13, 1994 (FRL-4870-4)).
        g. Notice containing the 35th ITC Report to the EPA Administrator 
    (59 FR 67596, December 29, 1994 (FRL-4923-2)).
        h. TSCA Sections 8(a) and 8(d) Final Rules for Chemicals Contained 
    in the 35th ITC Report to the EPA Administrator (60 FR 34879, July 5, 
    1995 (FRL-4954-9)).
        i. Notice containing the 36th ITC Report to the EPA Administrator 
    (60 FR 42982, August 17, 1995 (FRL-4965-6)).
        j. Small Business Size Standards; Final Rule, issued by the Small 
    Business Administration (SBA) (61 FR 3280, January 31, 1996).
        k. Notice containing EPA's Solicitation of Interested Parties for 
    Proposals for Enforceable Consent Agreements for Testing of 80 
    Chemicals of Interest to OSHA (61 FR 14773, April 3, 1996 (FRL-5359-
    3)).
        2. Correspondence:
        a. ARCO Chemical Company. Letter to Charles M. Auer, USEPA. 
    Proposal for Development of ECA for Tert-Butyl Alcohol (June 26, 1996).
        b. ARCO Chemical Company. Letter to Keith Cronin, USEPA. Letter 
    transmitting a Dermal Absorption Rate Study in the Male Rat for Tert-
    Butyl Alcohol (March 23, 1998).
        3. Other support documentation:
        EPA. ``EPA Interim Guidance for Implementing the Small Business 
    Regulatory Enforcement Fairness Act and Related Provisions of the 
    Regulatory Flexibility Act.'' EPA SBREFA Task Force (February 5, 1997).
    
    B. References
    
        1. ITC. Chemicals Under Consideration for the 32nd ITC Report; 
    Summary of Skin Absorption Data on OSHA Tier 2 Chemicals (September 22, 
    1993).
        2. Zeneca. Methyl Methacrylate: In Vitro Absorption through Human 
    Epidermis. Zeneca Central Toxicology Report No. CTL/P/4025 provided by 
    the Methacrylate Producers Association, Washington, D.C. (1993).
        3. Scott, R.C., Dugard, P.H., Ramsey, J.D., and Rhodes, C. In Vitro 
    Absorption of Some o-Phthalate Diesters through Human and Rat Skin. 
    Environmental Health Perspectives. 74:223-227 (1987).
        4. Mraz, J., Galova, E., Nohova, H., and Vitkova, D. Uptake, 
    Metabolism and Elimination of Cyclohexanone in Humans. International 
    Archives of Occupational Environmental Health. 66:203-208 (1994).
        5. ARCO Chemical Company. [14C]-t-Butyl Alcohol: Topical 
    Application: Dermal Absorption Study in the Male Rat. Huntington Life 
    Sciences (January 7, 1998).
        6. OSHA. Review of [14C]-t-Butyl Alcohol: Topical 
    Application: Dermal Absorption Study in the Male Rat. (June 24, 1998).
    
    [[Page 31083]]
    
        7. Bronaugh, R.L., and Collier, S.W. Protocol for In Vitro 
    Percutaneous Absorption Studies. In Vitro Percutaneous Absorption: 
    Principles, Fundamentals, and Applications. R.L. Bronaugh and H.I. 
    Maibach, Eds. CRC Press, Boca Raton, FL. pp. 237-241 (1991).
        8. Chemical Manufacturers Association (CMA). Letter to Charles M. 
    Auer, USEPA. (October 21, 1994).
        9. EPA. Economic Impact Analysis and Small Entity Impact Analysis 
    of Proposed TSCA Section 4(a) Test Rule for 47 Chemicals Targeted for 
    In Vitro Dermal Absorption Rate Testing. OPPT/EETD/EPAB, Washington, DC 
    (May 5, 1999).
        10. EPA. CEB Support to the OSHA Chemicals Test Rule--Number of 
    Workers Exposed and TRI Release Data. OPPT/EETD/CEB, Washington, DC 
    (March 1998).
        11. EPA. EPA Census of TSCA Testing Laboratories. Washington, DC 
    (October 10, 1996).
        12. EPA. Laboratory Cost Estimate for In Vitro Dermal Absorption 
    Rate Testing. OPPT/EETD/EPAB, Washington, DC (April 14, 1999).
        13. EPA. ``Treatment of 12(b) Export Notification Unit Costs for 
    Section 4 Test Rule Analyses.'' OPPT/EETD/EPAB, Washington, DC (April 
    1, 1999).
        14. EPA. ``Economic Analysis in Support of the TSCA 12(b) 
    Information Collection Request.'' OPPT/EETD/EPAB, Washington, DC 
    (October 30, 1998).
    
    VIII. Regulatory Assessment Requirements
    
    A. Executive Order 12866
    
        Under Executive Order 12866, entitled Regulatory Planning and 
    Review (58 FR 51735, October 4, 1993), this is not a ``significant 
    regulatory action'' subject to review by the Office of Management and 
    Budget (OMB), because this action is not likely to result in a rule 
    that meets any of the criteria for a ``significant regulatory action'' 
    provided in section 3(f) of the Executive Order.
        EPA has prepared an economic analysis of the potential impact of 
    this proposed rule, which is contained in a document entitled 
    ``Economic Impact Analysis and Small Entity Impact Analysis of Proposed 
    TSCA Section 4(a) Test Rule for 47 Chemicals Targeted for In Vitro 
    Dermal Absorption Rate Testing'' (Ref. 9). This document is available 
    as a part of the public version of the official record for this action 
    (instructions for accessing this document are contained in Unit I.B. of 
    this preamble), and is briefly summarized here. The costs developed in 
    the economic impact analysis are based on laboratory test cost 
    estimates that have been placed in the docket for this proposed rule 
    (Ref. 12).
        While legally subject to this test rule, processors of a subject 
    chemical would only be required to comply with the requirements of the 
    rule if they are directed to do so by EPA as described in 
    Sec. 799.5115(c)(5) and (c)(6) of the proposed regulatory text. EPA 
    would only require processors to test if no person in Tier 1 has 
    submitted a notice of its intent to conduct testing, or if, under 40 
    CFR 790.93, a problem occurs with the initiation, conduct, or 
    completion of the required testing, or the submission of the required 
    data to EPA. Because EPA has identified at least one manufacturer in 
    Tier 1 for each subject chemical, the Agency assumes that, for each 
    chemical in this proposed rule, at least one such person will submit a 
    letter of intent to conduct the required testing and that that person 
    will conduct such testing and will submit the test data to EPA. Because 
    processors would not need to comply with the rule initially, the 
    economic analysis does not address processors.
        To evaluate the potential economic impact of testing on 
    manufacturers of the chemical substances in this proposed rule, EPA 
    estimated the impact of testing requirements as a percentage of each 
    chemical's sale price. This measure compares the annualized testing 
    costs per pound (based on the conservative assumption that all 
    chemicals are produced in volumes of one million lbs), to the price per 
    pound for each chemical. First, annualized testing costs (including 
    laboratory and administrative expenditures) are calculated by 
    converting the total testing costs in the first year into an equivalent 
    series of expenditures over 15 years using a 7% discount rate. Second, 
    annualized testing costs are divided by one million lbs (the assumed 
    production volume per chemical) to derive the annualized unit (per 
    pound) testing cost. The price impacts--testing costs as a percentage 
    of each chemical's price--are calculated by dividing the annualized 
    unit testing cost by each unit price and multiplying by 100. The 
    Agency's estimated total costs of testing (including both laboratory 
    and administrative costs), annualized testing cost, price impacts, and 
    public reporting burden hours for the chemicals are presented in the 
    economic analysis (Ref. 9).
        Based on the economic analysis, the total one-time cost of this 
    action, if finalized as proposed, is estimated to be $1.55 million. 
    When this cost is annualized over 15 years using a 7% discount rate, 
    the total annualized cost is estimated to be $170,576, with an 
    estimated annualized cost of $3,628 per chemical. In addition, the 
    estimated cost of the TSCA section 12(b)(1) export notification, which, 
    in the final rule, would be required for the first export to a 
    particular country of a chemical subject to the rule, is estimated to 
    be $83.38 for the first time that an exporter must comply with TSCA 
    section 12(b)(1) export notification requirements, and $19.08 for each 
    subsequent export notification submitted by that exporter (Ref. 9, 13, 
    and 14).
        The economic impacts of the testing, expressed as a percentage of 
    each chemical's sale price, range from 0.09% to 3.3%, with an average 
    impact of 0.64%. EPA estimates that 5 of the 35 chemicals for which 
    price data are available will experience an adverse impact of 1% or 
    greater under the assumption that production volumes for these 
    chemicals are one million lbs. In fact, these chemicals are all 
    manufactured or imported in excess of 10 million lbs, reducing the 
    estimated impact by a factor of 10 to less than 1%. For the remaining 
    12 chemicals without price data, EPA estimates that with annualized 
    testing costs of $3,628 per chemical and one million lbs production 
    volumes each, an economic impact of 1% or greater would occur only at a 
    sales price below $0.36 per lb. Given that the average price for the 
    other 35 chemicals is $0.97 per lb (prices range from $0.11 to $3.96 
    per lb), that the unavailability of price data for these 12 chemicals 
    may indicate that they are higher priced specialty chemicals, and that 
    their production volumes are likely to be higher than the one million 
    lbs minimum, the likelihood of an adverse impact is low.
    
    B. Executive Order 12898
    
        This proposed rule does not involve special considerations of 
    environmental-justice related issues pursuant to Executive Order 12898, 
    entitled Federal Actions to Address Environmental Justice in Minority 
    Populations and Low-Income Populations (59 FR 7629, February 16, 1994).
    
    C. Executive Order 13045
    
        Executive Order 13045, entitled Protection of Children from 
    Environmental Health Risks and Safety Risks (62 FR 19885, April 23, 
    1997), does not apply to this proposed rule, because it is not 
    ``economically significant'' as defined under Executive Order 12866; 
    and does not concern an
    
    [[Page 31084]]
    
    environmental health or safety risk that may have a disproportionate 
    effect on children. This proposed rule would require the development of 
    quantitative measures of dermal absorption rate to assist in evaluating 
    the potential contribution of the chemical substances proposed for 
    testing to total exposures to adult workers. The public is invited, 
    however, to submit or identify peer-reviewed studies and data, of which 
    EPA may not be aware, that assess results of early life exposure to the 
    47 chemicals proposed for testing in this document.
    
    D. Regulatory Flexibility Act
    
        Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA), 
    5 U.S.C. 601 et seq., the Agency hereby certifies that this rule, if 
    promulgated as proposed, will not have a significant economic impact on 
    a substantial number of small entities. The factual basis for the 
    Agency's determination is presented in the small entity impact analysis 
    prepared as part of the economic analysis for this proposed rule (Ref. 
    9), and is briefly summarized here. The costs developed in the small 
    entity impact analysis are based on the laboratory test cost estimates 
    that have been placed in the docket for this proposed rule (Ref. 12).
        For the purpose of analyzing potential impacts on small entities, 
    EPA used the RFA definition of small entities in RFA section 601(6). 
    Under this section, a small entity may be a small government, a small 
    non-profit organization, or a small business. Because EPA does not 
    believe that governments or non-profit organizations are likely to be 
    burdened by testing requirements under this proposed rule, EPA's 
    analysis presents only the estimated potential impacts on small 
    businesses.
        Section 601(3) of the RFA establishes as the default definition of 
    small business the definition used in section 3 of the Small Business 
    Act (15 U.S.C. 632) under which the SBA establishes small business size 
    standards (13 CFR 121.201). For this proposed rule, EPA has analyzed 
    the potential small business impacts using the size standards 
    established under the RFA section 601(3) definition.
        In addition, in analyzing potential impacts, the RFA recognizes 
    that it may be appropriate at times for Federal agencies to use an 
    alternate definition of small business. As such, RFA section 601(3) 
    also provides that an agency may establish a different definition of 
    small business after consultation with the SBA Office of Advocacy and 
    after notice and an opportunity for public comment. Even though the 
    Agency has used the default SBA definition of small business to conduct 
    its analysis of potential small entity impacts for this proposed rule, 
    EPA does not believe that the SBA size standards are generally the best 
    size standards to use in assessing potential small entity impacts with 
    regard to TSCA section 4(a) test rules.
        The SBA size standards, which are primarily intended to define 
    whether a business entity is eligible for Federal government programs 
    and preferences reserved for small businesses (13 CFR 121.101), ``seek 
    to ensure that a concern that meets a specific size standard is not 
    dominant in its field of operation'' (13 CFR 121.102(b)). See section 
    632(a)(1) of the Small Business Act. The SBA size standard is generally 
    based on the number of employees an entity in a particular industrial 
    sector may have. For example, in the chemical manufacturing industrial 
    sector (i.e., SIC 28 and SIC 29), approximately 98% of the industries 
    would be classified as small businesses under the default SBA 
    definition. The SBA size standard for 75% of this industry sector is 
    500 employees, and the size standards for 23% of this industry sector 
    are 750, 1,000, or 1,500 employees. As a result, when assessing the 
    potential impacts of test rules on chemical manufacturers, EPA believes 
    that a standard based on total annual sales may provide a more 
    appropriate means to judge the ability of a chemical manufacturing firm 
    to support chemical testing without significant costs or burdens.
        EPA is currently determining what level of annual sales would 
    provide the most appropriate size cutoff with regard to various 
    segments of the chemical industry usually impacted by TSCA section 4(a) 
    test rules, but has not yet reached a determination. As stated in this 
    unit, therefore, the factual basis for the RFA determination for this 
    proposed rule is based on an analysis using the default SBA size 
    standards. Although EPA is not proposing to establish an alternate 
    small business definition in the small entity impact analysis conducted 
    for this proposed rule, the analysis includes the results of 
    calculations using a size standard based on total annual sales. EPA is 
    interested in receiving comments on whether the Agency should consider 
    establishing an alternate small business definition to use in the small 
    entity impact analyses for future TSCA section 4(a) test rules, and 
    what size cutoff may be appropriate.
        Based on the Agency's estimated total costs for this proposed rule, 
    which are summarized in Unit VIII.A. of this preamble, EPA estimates 
    that the annualized cost for the testing in this proposed rule will be 
    $3,628 per chemical. As discussed previously, EPA was unable to obtain 
    any price information on 12 of the 47 chemicals in this proposed test 
    rule. Nevertheless, EPA provides an estimate of the price of these 
    chemicals in the economic analysis, and concludes that the total cost 
    of testing these 47 chemicals as proposed, will not result in a 
    significant impact on the chemical manufacturers subject to the 
    proposed rule, regardless of their size. EPA identified a total of 102 
    ultimate corporate entities (UCEs) that would be potentially impacted 
    by the proposed test rule. None of these manufacturers would experience 
    a significant impact as a result of the rule.
        In addition, the estimated cost of the TSCA section 12(b)(1) export 
    notification, which, as a result of the final rule, would be required 
    for the first export to a particular country of a chemical subject to 
    the rule, is estimated to be $83.38 for the first time that an exporter 
    must comply with TSCA section 12(b)(1) export notification 
    requirements, and $19.08 for each subsequent export notification 
    submitted by that exporter (Ref. 9, 13, and 14). EPA has concluded that 
    the costs of TSCA section 12(b)(1) export notification would have a 
    negligible impact on exporters of the chemicals in the final rule, 
    regardless of the size of the exporter.
        The Agency has also examined the standard practices that industry 
    uses in carrying out chemical testing in response to test rules, such 
    as this one. Based on that examination, EPA believes that:
        1. Small businesses do not perform the testing themselves, nor do 
    they participate in the organization of the testing effort, because 
    health effects testing of chemical substances is generally carried out 
    by consortia of the large manufacturers or importers of the chemical 
    substances;
        2. A small business would experience only very minor costs, if any, 
    in securing an exemption from testing requirements, because exemption 
    request requirements, described generally at 40 CFR 790.80 through 
    790.99 and the proposed regulatory text at Sec. 799.5115(c)(2), (c)(5), 
    and (c)(7), are minimal and EPA does not charge a fee for filing such a 
    request; and
        3. Small businesses are unlikely to be affected by the 
    reimbursement requirements because under the reimbursement provisions 
    described in 40 CFR part 791, manufacturers and importers with a 
    significant share of production or importation are the entities that 
    will likely pay the highest share of testing costs, and the marginal
    
    [[Page 31085]]
    
    benefit of securing reimbursement from small contributors may not be 
    worth the cost.
        Information relating to this determination has been included in the 
    public version of the official record for the proposed rule. This 
    information will also be provided to the SBA Chief Counsel for Advocacy 
    upon request. Any comments regarding the impacts that this action may 
    impose on small entities, or regarding whether the Agency should 
    consider establishing an alternate definition of small business to be 
    used for analytical purposes for future test rules and what size cutoff 
    may be appropriate, should be submitted to the Agency in the manner 
    specified in Unit I.C. of this preamble.
    
    E. Paperwork Reduction Act
    
        Pursuant to the Paperwork Reduction Act (PRA) (44 U.S.C. 3501 et 
    seq.), an Agency may not conduct or sponsor, and a person is not 
    required to respond to, a collection of information that is subject to 
    approval under the PRA, unless it displays a currently valid OMB 
    control number. The OMB control numbers for EPA's regulations, after 
    appearing in the preamble of the final rule, are listed in 40 CFR part 
    9, and included on the related collection instrument. The information 
    collection activities related to chemical testing under TSCA section 
    4(a) have already been approved under OMB control number 2070-0033 (EPA 
    ICR# 1139), and the information collection activities related to export 
    notification under TSCA section 12(b)(1) are already approved under OMB 
    control number 2070-0030 (EPA ICR# 0795). Since this proposed rule does 
    not contain any new information collection activities, additional 
    review and approval of these activities by OMB under the PRA is not 
    necessary.
        Although the information collection activities contained in this 
    proposed rule have already been approved by OMB, the total burden hours 
    currently approved for the information collection activities related to 
    chemical testing in general include an average burden estimate to cover 
    future test rules. As described in the information collection 
    instrument for chemical testing, the Agency's total burden estimate 
    specifically accounts for the potential issuance of approximately 7 
    final test rules during the approval period, with an estimated burden 
    of less than 20,000 burden hours each. EPA believes that the existing 
    approval includes a sufficient burden hour allocation to cover the 
    estimated burden related to this proposed rule, if finalized as 
    proposed. When the final rule is issued, EPA will verify that the 
    approved burden hours will cover the estimated burden for the final 
    rule, or request that the total approved burden hour allocation be 
    increased accordingly.
        The standard chemical testing program involves the submission of 
    letters of intent to test (or exemption applications), study plans, 
    semi-annual progress reports, and test results. For this proposed rule, 
    EPA estimates that the information collection activities related to 
    chemical testing would result in 105.4 burden hours for each chemical, 
    for a total estimated burden increase of 4,954 hours (Ref. 9). The 
    estimated burden of the information collection activities related to 
    export notification is 0.5-1.5 burden hours for each chemical/country 
    combination (Ref. 9). In estimating the total burden hours approved for 
    the information collection activities related to export notification, 
    the Agency has included sufficient burden hours to accommodate any 
    export notifications that may be required by the Agency's issuance of 
    final chemical test rules (Ref. 9, 13, and 14). As such, EPA does not 
    expect to need to request an increase in the total burden hours 
    approved by OMB for export notifications.
        As defined by the PRA and 5 CFR 1320.3(b), burden means the total 
    time, effort, or financial resources expended by persons to generate, 
    maintain, retain, or disclose or provide information to or for a 
    Federal agency. This includes the time needed to review instructions; 
    develop, acquire, install, and utilize technology and systems for the 
    purposes of collecting, validating, and verifying information, 
    processing and maintaining information, and disclosing and providing 
    information; adjust the existing ways to comply with any previously 
    applicable instructions and requirements; train personnel to be able to 
    respond to a collection of information; search data sources; complete 
    and review the collection of information; and transmit or otherwise 
    disclose the information.
        Comments are requested on the Agency's need for this information, 
    the accuracy of the provided burden estimates, and any suggested 
    methods for minimizing respondent burden, including through the use of 
    automated collection techniques. Send comments to EPA as part of your 
    overall comments on this proposed action in the manner specified in 
    Unit I.C. of this preamble. In the final rule, the Agency will address 
    any comments received regarding the information collection requirements 
    contained in this proposal.
    
    F. Unfunded Mandates Reform Act
    
        Pursuant to Title II of the Unfunded Mandates Reform Act of 1995 
    (UMRA), Pub. L. 104-4, EPA has determined that this proposed rule does 
    not contain a Federal mandate that may result in expenditures of $100 
    million or more for State, local, and tribal governments, in the 
    aggregate, or the private sector in any 1 year. It is estimated that 
    the total one-time cost of the rule, which is summarized in Unit 
    VIII.A. of this preamble, is $1.55 million, with the total annualized 
    cost estimated to be $170,576, and the estimated annual cost per 
    chemical to be $3,628. In addition, EPA has determined that this 
    proposed rule does not significantly or uniquely affect small 
    governments. Accordingly, today's proposed rule is not subject to the 
    requirements of UMRA sections 202, 203, 204, or 205.
    
     G. Executive Order 12875
    
         Under Executive Order 12875, entitled  Enhancing the 
    Intergovernmental Partnership  (58 FR 58093, October 28, 1993), EPA may 
    not issue a regulation that is not required by statute and that creates 
    a mandate upon a State, local, or tribal government, unless the Federal 
    government provides the funds necessary to pay the direct compliance 
    costs incurred by those governments, or EPA consults with those 
    governments. If EPA complies by consulting, Executive Order 12875 
    requires EPA to provide to OMB a description of the extent of EPA's 
    prior consultation with representatives of affected State, local, and 
    tribal governments, the nature of their concerns, any written 
    communications from the governments, and a statement supporting the 
    need to issue the regulation. In addition, Executive Order 12875 
    requires EPA to develop an effective process permitting elected 
    officials and other representatives of State, local, and tribal 
    governments ``to provide meaningful and timely input in the development 
    of regulatory proposals containing significant unfunded mandates.''
         EPA does not believe the today's proposed rule under TSCA section 
    4(a) creates a Federal mandate on State, local, or tribal governments, 
    and thus, EPA does not believe that the requirements of section 1(a) of 
    Executive Order 12875 apply to this rule. The Agency does not know of 
    any State, local, or tribal governments that would be subject to the 
    requirements of the rule if it were promulgated as proposed. In the 
    history of the TSCA section 4(a) testing program, the Agency has never 
    received a letter of intent to
    
    [[Page 31086]]
    
    test or an exemption application from a State, local, or tribal 
    government. EPA is requesting comment on whether any State, local, or 
    tribal government would be subject to the requirements of the proposed 
    rule. If, on the basis of these comments, EPA determines that the rule 
    would create a Federal mandate, the Agency will consult with 
    representatives of affected State, local, or tribal governments in 
    accordance with the Executive Order prior to promulgating the final 
    rule.
    
    H. Executive Order 13084
    
        Under Executive Order 13084, entitled Consultation and Coordination 
    with Indian Tribal Governments (63 FR 27655, May 19, 1998), EPA has 
    determined that this proposed rule does not significantly or uniquely 
    affect the communities of Indian tribal governments. This determination 
    is based on the Agency's belief that, as a practical matter, the burden 
    of chemical testing under TSCA section 4(a) rules has traditionally 
    fallen on large, private sector manufacturers rather than on tribal 
    governments. Accordingly, the requirements of section 3(b) of Executive 
    Order 13084 do not apply to this proposed rule.
    
    I. National Technology Transfer and Advancement Act
    
        Section 12(d) of the National Technology Transfer and Advancement 
    Act of 1995 (NTTAA) (15 U.S.C. 272 note), directs EPA to use voluntary 
    consensus standards in its regulatory activities unless to do so would 
    be inconsistent with applicable law or otherwise impractical. Voluntary 
    consensus standards are technical standards (e.g., materials 
    specifications, test methods, sampling procedures, and business 
    practices) that are developed or adopted by voluntary consensus 
    standards bodies. The NTTAA directs EPA to provide Congress, through 
    OMB, explanations when the Agency decides not to use available and 
    applicable voluntary consensus standards.
        If the Agency has made findings under TSCA section 4(a), EPA is 
    required by TSCA section 4(b) to include specific standards for the 
    development of data in test rules. The testing that would be required 
    under this rule would be conducted according to the enforceable in 
    vitro dermal absorption rate test standard proposed in this document. 
    This test standard was developed by EPA in conjunction with ITC member 
    and liaison agencies (CPSC, DoD, FDA, NIOSH, and OSHA). It was based on 
    the methods of Bronaugh and Collier (Bronaugh, R.L., and Collier, S.W., 
    Protocol for In Vitro Percutaneous Absorption Studies, In Vitro 
    Percutaneous Absorption: Principles, Fundamentals, and Applications. 
    R.L. Bronaugh and H.I. Maibach, Eds. CRC Press, Boca Raton, FL. pp. 
    237-241 (1991)) (Ref. 7) , and modified in response to public comments. 
    The group of scientists that developed this test standard did so based 
    on their experience with the methodologies available for conducting 
    this type of testing. As a result of their collective expertise in 
    these methodologies, they considered the method developed for this 
    testing program to be an effective and efficient method for testing a 
    large number of chemicals to determine an in vitro dermal absorption 
    rate using human cadaver skin.
        EPA is not aware of any potentially applicable voluntary consensus 
    standards which needed to be considered in lieu of the in vitro dermal 
    absorption rate test standard included in this proposed rule. The 
    Agency invites comment on the potential use of voluntary consensus 
    standards in this proposed rule, and, specifically, invites the public 
    to identify potentially applicable voluntary consensus standard(s) and 
    to explain why such standard(s) should be used here.
    
    List of Subjects in 40 CFR Part 799
    
         Environmental protection, Chemicals, Hazardous substances, 
    Reporting and recordkeeping requirements, Laboratories.
    
        Dated: June 1, 1999.
    
    Susan H. Wayland,
    
    Acting Assistant Administrator for Prevention, Pesticides and Toxic 
    Substances.
        Therefore, it is proposed that 40 CFR chapter I, subchapter R, be 
    amended as follows:
    
    PART 799--[AMENDED]
    
        1. The authority citation for part 799 would continue to read as 
    follows:
    
        Authority: 15 U.S.C. 2603, 2611, 2625.
    
        2. By adding Sec. 799.5115 to subpart D to read as follows:
    
    
     Sec. 799.5115  Chemical testing requirements for certain chemicals of 
    interest to the Occupational Safety and Health Administration.
    
        (a) What substances will be tested under this section? Table 2 in 
    paragraph (i) of this section identifies the chemical substances that 
    must be tested under this section. The purity of each test substance 
    must be 99% or greater unless otherwise specified in this section.
        (b) Am I subject to this section? (1) If you manufacture (including 
    import) or intend to manufacture, or process or intend to process, any 
    chemical substance listed in Table 2 of paragraph (i) of this section 
    at any time from the effective date specified in Table 2 of paragraph 
    (i) of this section to the end of the test data reimbursement period as 
    defined in 40 CFR 791.3(h), you are subject to this section with 
    respect to that chemical substance.
        (2) If you do not know or cannot reasonably ascertain that you 
    manufacture or process a chemical substance listed in Table 2 of 
    paragraph (i) of this section during the time period described in 
    paragraph (b)(1) of this section (based on all information in your 
    possession or control, as well as all information that a reasonable 
    person similarly situated might be expected to possess, control, or 
    know, or could obtain without unreasonable burden), you are not subject 
    to this section with respect to that chemical substance.
        (c) If I am subject to this section, when must I comply with it? 
    (1)(i) Persons subject to this section are divided into two groups, as 
    set forth in Table 1 of this paragraph: Tier 1 (persons initially 
    required to comply) and Tier 2 (persons not initially required to 
    comply). If you are subject to this section, you must determine if you 
    fall within Tier 1 or Tier 2, based on Table 1 of this paragraph.
    
    [[Page 31087]]
    
    
    
       Table 1.--Persons Subject to the Rule: Persons in Tier 1 and Tier 2
    ------------------------------------------------------------------------
     Persons initially required to comply  Persons not initially required to
          with this section (Tier 1)       comply with this section (Tier 2)
    ------------------------------------------------------------------------
    Persons not otherwise          Persons that manufacture
     specified in column 2 of this table    (as defined at TSCA section
     that manufacture (as defined at TSCA   3(7)) or intend to manufacture a
     section 3(7)) or intend to             chemical substance included in
     manufacture a chemical substance       this section solely as one or
     included in this section.              more of the following:
                                           --As a byproduct (as defined at
                                            40 CFR 791.3(c));
                                           --As an impurity (as defined at
                                            40 CFR 790.3);
                                           --As a naturally occurring
                                            substance (as defined at 40 CFR
                                            710.4(b));
                                           --As a non-isolated intermediate
                                            (as defined at 40 CFR 704.3);
                                           --As a component of a Class 2
                                            substance (as described at 40
                                            CFR 720.45(a)(1)(i));
                                           --In amounts of less than 500
                                            kilograms (kg) (1,100 lbs)
                                            annually (as described at 40 CFR
                                            790.42(a)(4)); or
                                           --For research and development
                                            (as described at 40 CFR
                                            790.42(a)(5)).
                                           Persons that process (as
                                            defined at TSCA section 3(10))
                                            or intend to process a chemical
                                            substance included in this
                                            section (see 40 CFR
                                            790.42(a)(2)).
    ------------------------------------------------------------------------
    
    
        (ii) Table 1 of paragraph (c)(1)(i) of this section expands the 
    list of persons specified in Sec. 790.42(a)(2), (a)(4), and (a)(5) of 
    this chapter, who, while legally subject to this section, must comply 
    with the requirements of this section only if directed to do so by EPA 
    under the circumstances set forth in paragraphs (c)(4) and (c)(5) of 
    this section.
        (2) If you are in Tier 1 with respect to a chemical substance 
    listed in Table 2 of paragraph (i) of this section, you will be 
    required to comply with this section with regard to that chemical 
    substance, as described in paragraph (d) of this section, no later than 
    30 days after the effective date specified in Table 2 of paragraph (i) 
    of this section for that chemical substance. Sections 790.45(a) and 
    790.80(b)(1) of this chapter do not apply to this section.
        (3) If you are in Tier 2 with respect to a chemical substance 
    listed in Table 2 of paragraph (i) of this section, you are considered 
    to have an automatic conditional exemption and you will be required to 
    comply with this section with regard to that chemical substance only if 
    directed to do so by EPA under paragraphs (c)(5) or (c)(6) of this 
    section.
        (4) If no person in Tier 1 has notified EPA of its intent to 
    conduct one or more of the tests required by this section on any 
    chemical substance listed in Table 2 of paragraph (i) of this section 
    within 30 days after the effective date in Table 2 of paragraph (i) of 
    this section, EPA will publish a Federal Register document that will 
    specify the test and the chemical substance for which no letter of 
    intent has been submitted. Section 790.48(b)(2) of this chapter does 
    not apply to this section.
        (5) If you are in Tier 2 with respect to a chemical substance 
    listed in Table 2 of paragraph (i) of this section, and if you 
    manufacture or process this chemical as of the effective date specified 
    in Table 2 of paragraph (i) of this section, or within 30 days after 
    publication of the Federal Register document described in paragraph 
    (c)(4) of this section, you must do the following: For each test on 
    that chemical specified in the Federal Register document described in 
    paragraph (c)(4) of this section, either notify EPA by letter of your 
    intent to test or submit to EPA an exemption application. You must 
    comply within 30 days after the date of publication of the Federal 
    Register document described in paragraph (c)(4) of this section. 
    Sections 790.48(b)(3), and 790.80(a)(2) and (b)(1) of this chapter do 
    not apply to this section.
        (6) If a problem occurs with the initiation, conduct, or completion 
    of the required testing or the submission of the required data with 
    respect to a chemical substance listed in Table 2 of paragraph (i) of 
    this section, under the procedures in 40 CFR 790.93 and 790.97, EPA 
    will terminate all testing exemptions with respect to that substance 
    and may notify persons in Tier 1 and Tier 2 that they are required to 
    submit letters of intent to test or exemption applications within a 
    specified period of time. A notification will be given by certified 
    letter or by publication of a Federal Register document.
        (7) If you are required to comply with this section, but your 
    manufacturing or processing of a chemical substance listed in Table 2 
    of paragraph (i) of this section begins after the applicable compliance 
    date referred to in paragraphs (c)(2), (c)(5) or (c)(6) of this 
    section, you must comply by submitting a letter of intent to test or an 
    exemption application as of the day you begin manufacturing or 
    processing. Sections 790.45(d)(1) and (d)(2), and 790.80(b)(2) and 
    (b)(3) of this chapter do not apply to this section.
        (d) What must I do to comply with this section? (1) To comply with 
    this section you must either:
        (i) Submit to EPA a letter of intent to test, conduct the testing 
    specified in Table 2 of paragraph (i) of this section, and submit the 
    test data to EPA; or
        (ii) Apply to and obtain from EPA an exemption from testing.
        (2) You must also comply with the procedures governing test rule 
    requirements in part 790 of this chapter, including the submission of 
    letters of intent to test or exemption applications, the conduct of 
    testing, and the submission of data; part 792 of this chapter; and this 
    section.
        (e) If I do not comply with this section, when will I be considered 
    in violation of it? You will be considered in violation of this section 
    as of 1 day after the date by which you are required to comply with 
    this section. Sections 790.45(e) and (f) of this chapter do not apply 
    to this section.
        (f) How are EPA's data reimbursement procedures affected for 
    purposes of this section? If persons subject to this section are unable 
    to agree on the amount or method of reimbursement for test data 
    development for one or more chemical substances included in this 
    section, any person may request a hearing as described in 40 CFR part 
    791. In the determination of fair reimbursement shares under this 
    section, if the hearing officer chooses to use a formula based on 
    production volume, the total production volume amount will include 
    amounts of a chemical substance produced as an impurity.
        (g) Who must comply with the export notification requirements? Any 
    person who exports, or intends to export, a chemical substance listed 
    in Table 2 of paragraph (i) of this section is subject to part 707, 
    subpart D, of this chapter.
        (h) What test standard must I follow? The chemical substances 
    identified by Chemical Abstract Service (CAS) registry number and 
    chemical name in Table 2 of paragraph (i) of this section must be 
    tested as follows:
    
    [[Page 31088]]
    
        (1) Applicability. This in vitro dermal absorption rate test 
    standard must be used for all testing conducted under this section.
        (2) Source. The source used to develop this test standard is the 
    ``Protocol for In Vitro Percutaneous Absorption Studies,'' (Referenced 
    in paragraph (h)(8)(i)(A) of this section).
        (3) Purpose. In the assessment and evaluation of the 
    characteristics of a chemical substance or mixture (test substance), 
    determination of the rate of absorption of the chemical substance where 
    dermal exposure to the chemical substance in the workplace may result 
    in systemic toxicity is important. This test standard is designed to 
    develop data on the rate at which chemicals are absorbed through the 
    skin so that the body burden of chemical resulting from dermal exposure 
    in the workplace can be better evaluated.
        (4) Principles of the test method. This test standard describes 
    procedures for measuring a permeability constant (Kp) and a short-term 
    in vitro absorption rate for chemical substances in liquid form. The 
    test standard utilizes in vitro diffusion cell techniques which allow 
    absorption studies to be conducted with human skin. In vitro diffusion 
    studies are necessary for measuring a Kp. This test standard specifies 
    the use of cadaver skin and static diffusion cells to maintain the 
    viability of the skin, thus, more closely simulating in vivo 
    conditions. It also requires the use of radiolabeled test chemicals 
    unless it can be demonstrated that procedures utilizing a non-
    radiolabeled test substance are able to measure the substance with a 
    sensitivity equivalent to the radiolabeled method.
        (5) Test procedure--(i) Choice of membrane--(A) Skin selection. 
    Human cadaver skin must be used in all testing conducted under this 
    test standard. The most accurate absorption-rate data for regulatory 
    concerns related to human health would be obtained with live human 
    skin. Because this test standard requires the use of static diffusion 
    cells, maintenance of skin viability is not necessary. However, the 
    time elapsed between death and harvest of the tissue must be reported.
        (B) Number of samples. Data from a total of at least six samples 
    obtained from at least three human subjects must be averaged to allow 
    for biological variation among subjects.
        (C) Anatomical region. In order to minimize the variability in skin 
    absorption measurements for these tests, samples of human skin must be 
    obtained from the abdominal region of human subjects of known source 
    and disease state. Variability in skin permeation is well known to 
    occur in different anatomical regions. The trunk and its extremities 
    have reasonably similar barrier properties (less than 2-fold 
    differences). Enhanced absorption can be observed in regions of the 
    face (4-fold) and the scrotum (20-fold). Small differences in regional 
    absorption may not be significant compared to intersubject variability
        (D) Validation of human skin barrier. Barrier properties of human 
    skin must be pretested with a standard compound such as tritiated water 
    prior to conducting an experiment with the test chemical because 
    barrier alteration can result from surgery or topical scrubbing, as 
    discussed in the reference in paragraph (h)(8)(i)(B) of this section.
        (ii) Preparation of membrane. Full thickness skin must not be used. 
    Because chemicals are taken up by blood vessels directly beneath the 
    epidermis in vivo, this in vitro test standard must be conducted using 
    a membrane with most of the dermis removed. This is particularly 
    important for hydrophobic chemicals that diffuse slowly through the 
    dermis. A suitable membrane must be prepared from skin with a dermatome 
    at a thickness of 200 to 500 millimeters (mm). The microtomed skin 
    samples can be stored frozen for up to 2 weeks, if necessary, provided 
    that they are frozen quickly and the barrier properties of the samples 
    are confirmed.
        (iii) Diffusion cell design. Static diffusion cells must be used in 
    these studies. The testing laboratory must verify that the difference 
    in the concentration of the test compound across the skin membrane does 
    not decrease by more than 10% during the experiment. This will ensure 
    that the test compound concentration in the receptor fluid does not 
    alter the penetration rate. Concentration of the neat liquid must be 
    taken as the density of the compound.
        (iv) Temperature. Skin must be maintained at a physiological 
    temperature of 32 deg. Celsius.
        (v) Testing hydrophobic chemicals. Chemicals with water solubility 
    less than about 10 milligrams/liter do not freely partition from skin 
    into aqueous receptor fluid. To increase the water solubility of such 
    hydrophobic chemicals, polyethoxyoleate (polyethylene glycol (PEG) 20 
    oleyl ether) must be added to the receptor fluid at a concentration of 
    6%. To ensure that an increase in concentration of the chemical in the 
    receptor fluid does not alter penetration rate, the concentration 
    difference across the membrane must not decrease by more than 10% 
    during the experiment.
        (vi) Vehicle. If the test chemical is a liquid at room temperature 
    and does not damage the skin during the determination of Kp, it must be 
    applied neat. If the chemical cannot be applied neat because it is a 
    solid at room temperature or because it damages the skin when applied 
    neat, it must be dissolved in water. If the concentration of a 
    hydrophobic chemical in water is not high enough so that a steady-state 
    absorption can be obtained, the chemical must be dissolved in isopropyl 
    myristate. A sufficient volume of liquid must be used to completely 
    cover the skin and provide the amount of test chemical needed as 
    described in paragraph (h)(5)(vii) of this section.
        (vii) Dose--(A) Kp. An ``infinite dose'' of the test chemical must 
    be applied to the skin to achieve the steady-state rate of absorption 
    necessary for calculation of a Kp. The actual concentration required to 
    give an undepletable reservoir on the surface of the skin depends on 
    the rate of penetration of the test chemical. Preliminary studies may 
    be necessary to determine this concentration. The diffusion cell tops 
    must be covered with a stopper or with parafilm 7 to ensure that 
    significant evaporation of the vehicle or test chemical does not occur. 
    The skin barrier integrity must be verified at the end of the 
    experiment by measuring the absorption of a standard compound such as 
    tritiated water, as discussed in the reference in paragraph 
    (h)(8)(i)(B) of this section.
        (B) Short-term absorption rate. Short-term absorption rates must be 
    determined for all test chemicals. The dose of test chemical applied to 
    the skin must be sufficient to completely cover the exposed skin 
    surface. A minimum of four to six diffusion cells must be set up using 
    skin from a single subject and two to three of these shall be 
    terminated at 10 and 60 minutes. Skin absorption at each sampling time 
    is the sum of the receptor-fluid levels and the absorbed chemical that 
    remains in the skin, as discussed in the reference in paragraph 
    (h)(8)(i)(C) of this section. Unabsorbed chemical must be removed from 
    the skin surface by washing gently with soap and water. This procedure 
    must be repeated with skin from two additional subjects. In order to 
    ensure reliable short-term absorption rates, the diffusion cell tops 
    must be covered with a stopper or with parafilm 7 to prevent 
    evaporation of the test chemical.
        (viii) Study duration--(A) Kp. This in vitro dermal absorption rate 
    test must be performed until at least four absorption measurements are 
    obtained during the steady state absorption portion of the procedure. A 
    preliminary study may be
    
    [[Page 31089]]
    
    useful to establish time points for sampling. The required absorption 
    measurements can be accomplished in an hour or two with fast-
    penetrating chemicals but require 24 hours or longer for slow-
    penetrating chemicals. Unabsorbed material need not be removed from the 
    surface of the skin.
        (B) Short-term exposure rate. The test chemical must be applied to 
    skin for durations of at least 10 and 60 minutes. At the end of the 
    study, the unabsorbed material must be removed from the surface of the 
    skin with soap and water and the amount absorbed into the skin and 
    receptor fluid must be determined, as discussed in the reference in 
    paragraph (h)(8)(i)(C) of this section.
        (6) Results--(i) Kp. The Kp must be calculated by dividing the 
    steady-state rate of penetration (measured in micrograms x 
    hr-1 x centimeters (cm)-2) by the concentration 
    of the test chemical (measured in micrograms x cm-3) applied 
    to the skin. For example, if the steady-state rate is 1 microgram x 
    hr-1 x cm-2 and the concentration applied to the 
    skin is 1,000 micrograms x cm-3, then the Kp value is 
    calculated to be 0.001 cm x hr-1.
        (ii) Short-term exposure rate. The rates of penetration (micrograms 
    x hr-1 x cm-2 ) must be determined from the total 
    amount of test chemical found in the receptor fluid and skin after the 
    10- and 60-minute exposures.
        (7) Test reports. In addition to compliance with the TSCA Good 
    Laboratory Practice (GLP) Standards at 40 CFR part 792, the following 
    specific information must be collected and reported under paragraph (i) 
    of this section:
        (i) Test systems and test methods. (A) A description of the date, 
    time, and location of the test, the name(s) of the person(s) conducting 
    the test, the location of records pertaining to the test, as well as a 
    GLP statement. These statements must be certified by the signatures of 
    the individuals performing the work and their supervisors.
        (B) A description of the source, identity, and purity of the test 
    chemical and the source, identity, and handling of the test skin. There 
    must be a detailed description of the test procedure and all materials, 
    devices used and doses tested, as well as a detailed description and 
    illustration of flow-cell design. There must also be a description of 
    the skin preparation method including measurements of the skin membrane 
    thickness.
        (C) A description of the analytical techniques to be used, 
    including their accuracy, precision, and detection limits (in 
    particular for non-radiolabeled tests), and, if a radiolabel is used, 
    there must be a description of the radiolabel (e.g., type, location of, 
    and radiochemical purity of the label).
        (D) All data must be clearly identified as to dose and specimen. 
    Derived values (means, permeability coefficient, graphs, charts, etc.) 
    are not sufficient.
        (ii) Conduct of study. Data must be collected and reported on the 
    following:
        (A) Monitoring of testing parameters.
        (B) Temperature of chamber.
        (C) Receptor fluid pH.
        (D) Barrier property validation.
        (E) Analysis of receptor fluid for radioactivity or test chemical.
        (iii) Results. The Kp or short-term absorption rate must be 
    presented. In addition, all raw data from each individual diffusion 
    cell must be maintained to support the calculations of Kp and short-
    term exposure rates. When radiolabeled compounds are used, a full 
    balance of the radioactivity must be presented, including cell rinsing 
    and stability of the test substance in the donor compartment.
        (8) References. (i) For background information on this test 
    standard, the following references should be consulted. These 
    references are available at the TSCA Nonconfidential Information 
    Center, Rm. NE B-607, Environmental Protection Agency, 401 M St., SW., 
    Washington, DC, 12 noon to 4 p.m., Monday through Friday, except legal 
    holidays.
        (A) Bronaugh, R.L., and Collier, S.W. Protocol for In Vitro 
    Percutaneous Absorption Studies. In Vitro Percutaneous Absorption: 
    Principles, Fundamental, and Applications. R.L. Bronaugh and H.I. 
    Maibach, Eds. CRC Press, Boca Raton, FL. pp. 237-241 (1991).
        (B) Bronaugh, R.L., Stewart, R.F., and Simon, M. Methods for In 
    Vitro Percutaneous Absorption VII: Use of Excised Human Skin. Journal 
    of Pharmaceutical Sciences. Vol. 75, pp. 1094-1097 (1986).
        (C) Bronaugh, R.L., Stewart, R.F., and Storm, J.E. Extent of 
    Cutaneous Metabolism during Percutaneous Absorption of Xenobiotics. 
    Toxicology and Applied Pharmacology. Vol. 99, pp. 534-543 (1989).
        (ii) Two additional documents consulted in developing this test 
    standard are:
        (A)Walker, J.D., Whittaker, C. and McDougal, J.N. Role of the TSCA 
    Interagency Testing Committee in Meeting the U.S. Government Data 
    Needs: Designating Chemicals for Percutaneous Absorption Rate Testing. 
    Dermatoxicology. F. Marzulli and H. Maibach, Eds. Taylor & Francis, 
    Washington, DC. pp. 371-381 (1996).
        (B) Bronaugh, R.L. Stewart, R.F. Methods for In Vitro Percutaneous 
    Absorption Studies IV: The Flow-Through Diffusion Cell. Journal of 
    Pharmaceutical Sciences. Vol. 74, pp. 64-67 (1985).
        (i) Reporting requirements. The reports submitted under this 
    section must include the information specified in paragraph (h)(7) of 
    this section. Interim progress reports for each test must be submitted 
    every 6 months, beginning 6 months after the effective date of any 
    specific test listed in Table 2 of this paragraph. A final report for a 
    specific test must be submitted by the deadline indicated as the number 
    of months after the effective date shown in Table 2 of this paragraph.
    
    
         Table 2.--Required Testing: Chemical Substances Designated for In Vitro Dermal Absorption Rate Testing
    ----------------------------------------------------------------------------------------------------------------
                                                                               Number of Interim
                 CAS No.                 Chemical name    Deadline for final   (6 month) reports    Effective date
                                                                report             required
    ----------------------------------------------------------------------------------------------------------------
    60-29-7                            Ethyl ether                 9                   1
    74-96-4                            Ethyl bromide               9                   1
    75-05-8                            Acetonitrile                9                   1
    75-15-0                            Carbon disulfide            9                   1
    75-35-4                            Vinylidene                  9                   1
                                       chloride
    77-73-6                           Dicyclopentadiene            9                   1
    77-78-1                            Dimethyl sulfate            9                   1
    78-59-1                            Isophorone                  9                   1
    78-83-1                            Isobutyl alcohol            9                   1
    78-87-5                            Propylene                   9                   1
                                       dichloride
    78-92-2                            sec-Butyl alcohol           9                   1
    
    [[Page 31090]]
    
     
    79-20-9                            Methyl acetate              9                   1
    79-46-9                            2-Nitropropane              9                   1
    91-20-3                            Naphthalene                 9                   1
    92-52-4                           Biphenyl                     9                   1
    95-49-8                            o-Chlorotoluene             9                   1
    95-50-1                            o-Dichlorobenzene           9                   1
    97-77-8                            Disulfiram                  9                   1
    98-29-3                            tert-                       9                   1
                                       Butylcatechol
    99-99-0                           p-Nitrotoluene               9                   1
    100-00-5                          p-                           9                   1
                                       Nitrochlorobenzen
                                       e
    100-01-6                          p-Nitroaniline               9                   1
    100-44-7                          Benzyl chloride              9                   1
    106-42-3                           p-Xylene                    9                   1
    106-46-7                           p-Dichlorobenzene           9                   1
    107-06-2                          Ethylene                     9                   1
                                       dichloride
    107-31-3                           Methyl formate              9                   1
    108-03-2                           1-Nitropropane              9                   1
    108-90-7                           Chlorobenzene               9                   1
    108-93-0                           Cyclohexanol                9                   1
    109-66-0                           Pentane                     9                   1
    109-99-9                           Tetrahydrofuran             9                   1
    110-12-3                           Methyl isoamyl              9                   1
                                       ketone
    111-84-2                           Nonane                      9                   1
    120-80-9                           Catechol                    9                   1
    121-69-7                           Dimethylaniline             9                   1
    122-39-4                           Diphenylamine               9                   1
    123-42-2                          Diacetone alcohol            9                   1
    126-99-8                          beta-Chloroprene             9                   1
    127-19-5                          Dimethyl acetamide           9                   1
    142-82-5                          n-Heptane                    9                   1
    150-76-5                          p-Methoxyphenol              9                   1
    528-29-0                           o-Dinitrobenzene            9                   1
    628-63-7                          n-Amyl acetate               9                   1
    768-52-5                          N-Isopropylaniline           9                   1
    25013-15-4                        Vinyl toluene                9                   1
    34590-94-8                         Dipropylene                 9                   1
                                       glycol methyl
                                       ether
    ----------------------------------------------------------------------------------------------------------------
    
    
    [FR Doc. 99-14640 Filed 6-8-99; 8:45 am]
    BILLING CODE 6560-50-F
    
    
    

Document Information

Published:
06/09/1999
Department:
Environmental Protection Agency
Entry Type:
Proposed Rule
Action:
Proposed rule.
Document Number:
99-14640
Dates:
Comments, identified by docket control number OPPTS-42196, must be received by EPA on or before August 9, 1999. Your request to present oral comments must be in writing and must be received by EPA on or before July 9, 1999.
Pages:
31074-31090 (17 pages)
Docket Numbers:
OPPTS-42196, FRL-5760-3
RINs:
2070-AB07: Test Rules; Generic Entry for Proposed Decisions
RIN Links:
https://www.federalregister.gov/regulations/2070-AB07/test-rules-generic-entry-for-proposed-decisions
PDF File:
99-14640.pdf
CFR: (2)
40 CFR 799.5115(i)
40 CFR 799.5115