94-10975. Control of Air Pollution; Emission Standards for New Nonroad Spark-ignition Engines at or Below 19 Kilowatts  

  • [Federal Register Volume 59, Number 93 (Monday, May 16, 1994)]
    [Unknown Section]
    [Page 0]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 94-10975]
    
    
    [[Page Unknown]]
    
    [Federal Register: May 16, 1994]
    
    
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    ENVIRONMENTAL PROTECTION AGENCY
    40 CFR Part 90
    
    [FRL-4881-5]
    RIN 2060 AE29
    
     
    
    Control of Air Pollution; Emission Standards for New Nonroad 
    Spark-ignition Engines at or Below 19 Kilowatts
    
    AGENCY: Environmental Protection Agency (EPA).
    
    ACTION: Notice of proposed rulemaking.
    
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    SUMMARY: Today's action proposes emission standards for new nonroad 
    spark-ignition engines at or below 19 kilowatts (25 horsepower). This 
    action is authorized by section 213(a)(3) of the Clean Air Act as 
    amended. The proposed standards are expected to result in a 32 percent 
    reduction in hydrocarbon emissions and a 14 percent reduction in carbon 
    monoxide emissions from these engines by the year 2020 when complete 
    fleet turnover is projected.
    DATES: Comments must be received on or before July 15, 1994. A public 
    hearing will be held on June 21, at 10 a.m.; requests to present oral 
    testimony must be received on or before June 15, 1994.
    
    ADDRESSES: Interested parties may submit written comments (in 
    triplicate, if possible) for EPA consideration by addressing them as 
    follows: EPA Air and Radiation Docket, Attention: Docket Number A-93-
    25, 401 M Street SW., Washington, DC 20460. Materials relevant to this 
    rulemaking are contained in this docket and may be viewed at this 
    location from 8 a.m. until 4 p.m. Monday through Friday. As provided in 
    40 CFR part 2, a reasonable fee may be charged by EPA for photocopying. 
    The public hearing will be held at Dominos Farm, Ulrich room, lobby E, 
    24 Frank Lloyd, Ann Arbor, MI 48104.
    FOR FURTHER INFORMATION CONTACT: Lucie Audette, Office of Mobile 
    Sources, Certification Division, (313) 741-7878.
    
    SUPPLEMENTARY INFORMATION:
    
    I. Obtaining Copies of the Regulatory Language
    
        EPA has not included in this document the proposed regulatory 
    language or the draft Regulatory Support Document (RSD). Electronic 
    copies (on 3.5'' diskettes) of both the proposed regulatory language 
    and the draft RSD may be obtained free of charge by visiting, calling, 
    or writing the Environmental Protection Agency, Certification Division, 
    2565 Plymouth Road, Ann Arbor, MI 48105, (313) 741-7878. Refer to 
    Docket A-93-25. A copy is available for inspection in the docket (see 
    ADDRESSES).
        The proposed regulatory language and the draft RSD are also 
    available electronically on the Technology Transfer Network (TTN). TTN 
    is an electronic bulletin board system (BBS) operated by EPA's Office 
    of Air Quality Planning and Standards. Users are able to access and 
    download TTN files on their first call. After logging onto TTN BBS, to 
    navigate through the BBS to the files of interest, the user must enter 
    the appropriate command at each of a series of menus. The steps 
    required to access information on this rulemaking are listed below. The 
    service is free, except for the cost of the phone call.
    
    TTN BBS: 919-541-5742 (1,200-14,400 bps, no parity, eight data bits, 
    one stop bit) Voice help: 919-541-5384 Internet address: TELNET 
    ttnbbs.rtpnc.epa.gov Off-line: Mondays from 8:00 - 12:00 Noon ET
        1. Technology Transfer Network Top Menu: GATEWAY TO TTN 
    TECHNICAL AREAS (Bulletin Boards) Command: T
        2. TTN TECHNICAL INFORMATION AREAS  OMS - Mobile Sources 
    Information Command: M
        3. OMS BBS ==== MAIN MENU FILE TRANSFERS  Rulemaking & Reporting 
    Command: K
        4. RULEMAKING PACKAGES <6> Non-Road Command: 6
        5. Non-Road Rulemaking Area: File area #2 * * * Non-Road Engines 
    Command: 2
        6. Non-Road Engines
    
        At this stage, the system will list all available nonroad engine 
    files. To download a file, select a transfer protocol which will match 
    the terminal software on your own computer, then set your own software 
    to receive the file using that same protocol.
        If unfamiliar with handling compressed (i.e., ZIP'ed) files, go to 
    the TTN topmenu, System Utilities (Command: 1) for information and the 
    necessary program to download in order to unZIP the files of interest 
    after downloading to your computer. After getting the files you want 
    onto your computer, you can quit TTN BBS with the oodbye command.
    
    II. Contents
    
    III. Statutory Authority and Background
        A. Statutory Authority
        B. Background
    IV. Requirements of the Proposed Rule
        A. Overview
        B. General Enforcement Provisions
        C. Program Description and Rationale
    V. Discussion of Issues
        A. Use of Metric Units
        B. Use of Power Rating as Cutoff for Applicability
        C. Exclusion of Compression-ignition Engines
        D. Exclusion of Recreational Propulsion Engines
        E. Exclusion of Marine Propulsion Engines
        F. Nonroad Engine and Vehicle Definitions
        G. Definition of Handheld Equipment
        H. Requirements Applicable to Vehicle and Equipment 
    Manufacturers
        I. Effective Date
        J. Selection of Worst Case Emitter
        K. Adequacy of Test Cycle
        L. Alternative, Oxygenated, and Reformulated Fuels
        M. HC + NOX Standard for Class I and II Engines
        N. CO Standard for Handheld Engines Over 50 cc
        O. Cap on Noise
        P. Applicability of In-Use Standards
        Q. In-Use Testing Requirement
        R. Absence of Averaging, Banking, and Trading Programs
        S. Engine Manufacturer Requirement--Disclosure of Maximum 
    Exhaust Pressure and Minimum Inlet Pressure
        T. Direct Health Effects of Air Toxics and CO
        U. Catalyst Durability
        V. Test Procedure Requirements
        W. Duration of Certificates of Conformity, Definition of Model 
    Year, Annual Production Period
    VI. Environmental Benefit Assessment
        A. Estimated Emissions Impact of Proposed Regulation
        B. Health and Welfare Effects of HC Emissions
        C. Health and Welfare Effects of CO Emissions
        D. Roles of HC and NOX in Ozone Formation
        E. Health and Welfare Effects of Tropospheric Ozone
    VII. Technology Assessment
        A. Achievability of Proposed Emission Standards
        B. Proposed Emission Standards are Lowest Feasible
        C. Impact on Equipment
        D. Energy, Noise, and Safety
        E. Per Engine Cost Estimates Due to Proposed Standards
    VIII. Economic Effects
        A. Consumer Cost
        B. Incremental Economic Impacts
    IX. Cost-Effectiveness
    X. Administrative Requirements
        A. Administrative Designation and Regulatory Analysis
        B. Paperwork Reduction Act
        C. Impact on Small Entities
    
    III. Statutory Authority and Background
    
    A. Statutory Authority
    
        Authority for the actions proposed in this notice is granted to EPA 
    by sections 203, 204, 205, 206, 207, 208, 209, 213, 215, 216, and 
    301(a) of the Clean Air Act (CAA or Act) as amended (42 U.S.C. 7522, 
    7523, 7524, 7525, 7541, 7542, 7543, 7547, 7549, 7550, and 7601(a)).
        CAA section 213(a) directs EPA to: (1) Conduct a study of emissions 
    from nonroad engines and vehicles; (2) determine whether emissions of 
    carbon monoxide (CO), oxides of nitrogen (NOX), and volatile 
    organic compounds (VOCs) from nonroad engines and vehicles are 
    significant contributors to ozone or CO concentrations in more than one 
    area that has failed to attain the National Ambient Air Quality 
    Standards (NAAQS) for ozone and CO; and (3) regulate those categories 
    or classes of new nonroad engines and vehicles that, in EPA's judgment 
    cause or contribute to such air pollution. Under CAA section 213(a)(4), 
    EPA may also regulate emissions other than CO, NOX, and VOCs from 
    new nonroad engines and vehicles if EPA determines that such other 
    emissions significantly contribute to air pollution that may reasonably 
    be anticipated to endanger public health or welfare. The Nonroad Engine 
    and Vehicle Emission Study (hereafter, ``Nonroad Study'') required by 
    section 213(a)(1) was completed in November 1991. The Nonroad Study is 
    available in docket A-91-24. The determination of the significance of 
    emissions from nonroad engines and vehicles in more than one NAAQS 
    nonattainment area, required by section 213(a)(2), was proposed on May 
    17, 1993 (58 FR 28809) and is incorporated by reference into this 
    proposal. At the same time, the first set of regulations for a class or 
    category of nonroad engines that contribute to air pollution, required 
    by section 213(a)(3), was proposed (58 FR 28809) for new nonroad 
    compression-ignition (CI) engines at or above 37 kilowatts (kW). 
    Today's action continues to implement section 213(a)(3); it proposes 
    emission standards for nonroad spark-ignition (SI) engines at ornd 
    below 19 kW (25 horsepower) (hereafter, ``small SI engines''), another 
    class or category of nonroad engines that contributes to air pollution.
    
    Background
    
        On the basis of the Nonroad Study, EPA has proposed its 
    determination that emissions of CO, NOX, and VOCs from nonroad 
    engines and vehicles contribute significantly to ozone or CO in more 
    than one NAAQS nonattainment area (see 58 FR 28809, May 17, 1993). 
    According to the Nonroad Study, nonroad engines and vehicles contribute 
    an average of ten percent of summer VOCs in the 19 ozone nonattainment 
    areas included in the study. Small SI engines are the source of half of 
    those nonroad summer VOC emissions. In the 16 CO nonattainment areas 
    included in the study, nonroad engines and vehicles account on average 
    for nine percent of winter CO emissions. Small SI engines are the 
    source of 56 percent of the nonroad winter CO contribution, according 
    to the study.
        Since March 1992, EPA has held several public workshops and 
    meetings to solicit information on technical characteristics, 
    emissions, potential regulatory strategies, and general regulatory 
    issues related to small SI engines. Public notice of such meetings may 
    be found in the docket for this rulemaking.
        At the March 1992 public workshop, the Engine Manufacturers 
    Association and the Outdoor Power Equipment Institute encouraged 
    federal regulation of nonhandheld small SI engines and expressed 
    interest in working in a cooperative program with EPA to develop 
    regulations by November 1993. Likewise, the Portable Power Equipment 
    Manufacturers Association encouraged federal regulation of portable 2-
    stroke power equipment and expressed interest in working cooperatively 
    with EPA.
        Industry's interest in federal regulation of small SI engines may 
    be traced to California's efforts to develop a statewide regulatory 
    program. CAA section 209(e)(2) authorizes California to enforce 
    emission standards for certain nonroad engines if: (1) California 
    determines that such standards will be, in the aggregate, at least as 
    protective of public health and welfare as applicable Federal 
    standards, and such standards are not arbitrary and capricious, (2) 
    California needs such standards to meet compelling and extraordinary 
    conditions, and (3) California standards and accompanying enforcement 
    procedures are consistent with section 209(e)(2). (See 58 FR 45866, 
    September 6, 1991, for EPA's Notice of Proposed Rulemaking for 
    implementing section 209(e). This rulemaking is ongoing and the exact 
    criteria for EPA granting an authorization to California will be 
    prescribed in the final section 209(e) rule. Definitions of farm and 
    construction equipment are also provided in this section 209(e) rule.) 
    CAA section 209(e)(2) also authorizes other states to opt into 
    California standards. The California Air Resources Board (CARB) has 
    adopted standards for nonroad lawn and garden and utility SI and CI 
    engines from 0-25 horsepower (0-19 kilowatts). EPA is currently 
    reviewing CARB's section 209(e) authorization request for its lawn and 
    garden and utility rule. A decision will be issued once EPA's section 
    209(e) procedural rule is finalized. There is potential for other 
    states to adopt the California standards, which are scheduled to become 
    effective in 1995, if EPA decides to approve California's waiver 
    request.
        Following the March 1992 workshop, EPA determined that setting 
    emission standards for the small SI engine category might be suitable 
    for a consultative approach to rulemaking, such as negotiated 
    rulemaking. The Negotiated Rulemaking Act (5 U.S.C. 581-590) 
    establishes a framework for conducting negotiated rulemaking. Under 
    that Act, in deciding whether to conduct a negotiated rulemaking, the 
    head of an agency must consider several factors, including whether, at 
    the preproposal stage of development, the number of identifiable 
    parties who would come to the negotiating table is relatively limited, 
    the number of specific issues for which sufficient information and 
    technology is in hand for resolution is limited, and a time-forcing 
    factor exists that lends an air of urgency to issuance of the rule in 
    question. Negotiations are conducted through a committee chartered 
    under the Federal Advisory Committee Act (5 U.S.C. App. II section 
    9(c)). The goal of a regulatory negotiation committee is to reach 
    consensus on the language or issues involved in a rule. If consensus is 
    reached, it is used as the basis of the Agency's proposal.
        EPA initiated a convening process to determine the best way to work 
    with industry and other interested parties in developing regulations 
    for small SI engines. The conveners interviewed individuals in 
    leadership roles in key organizations identified by EPA to determine 
    what parties were interested in these regulations, what issues were 
    important to interested parties, and whether a consultative rulemaking 
    process would be feasible and appropriate. A copy of the convening 
    report, dated August 24, 1992, is available in the docket for this 
    rulemaking.
        The convening report recommended an exploratory meeting of 
    interested parties to discuss, but not initiate, a consultative 
    process. EPA determined that the number of parties who would come to 
    the negotiating table would be relatively limited, the number of 
    specific issues for resolution would be limited, sufficient information 
    and technology would be in hand or could be timely developed for 
    resolution of issues, and time-forcing factors existed. (See 58 FR 
    34389, June 25, 1993, for a complete discussion of the application of 
    the factors in this case.) Time-forcing factors lending an air of 
    urgency to issuance of the rule include the potential threat to 
    industry of patchwork regulation if a number of states opt into 
    California's program in order to attain national air quality goals. 
    More recently, an air of urgency has been created by the settlement of 
    Sierra Club v. Browner, Civ. No. 93-0197 NHJ (D.D.C. 1993), which 
    requires EPA to propose emission standards for small SI engines by 
    April 1994 and to promulgate such standards by May 1995.
        The exploratory meeting recommended in the convening report was 
    held in Ann Arbor, Michigan on November 16-17, 1992. Participants 
    decided that state and public interest representatives needed more 
    technical information to fully understand some of the regulatory issues 
    participants might face. It was also decided that another meeting was 
    necessary to discuss the potential design of a consultative process for 
    a small SI engine rulemaking. The technical briefing for state and 
    public interest representatives was conducted in Ann Arbor on December 
    16, 1992. On January 28-29, 1993, a meeting to discuss consultative 
    process design was held in Ann Arbor.
        At the January meeting, it was suggested that EPA consider a two-
    phased approach to regulation of small SI engines. In the suggested 
    first phase, EPA would propose regulations for new small SI engines 
    through the normal regulatory process rather than a consultative 
    process. It was suggested that Phase 1 regulations could be similar to 
    California's Regulation for 1995 and Later Utility and Lawn and Garden 
    Equipment Engines, modified as necessary to meet CAA requirements. (For 
    example, EPA's proposal could modify CARB's program by including 
    engines preempted from regulation in California.) The Phase 1 proposal 
    would be completed as soon as possible, but no later than the spring of 
    1994. The final rule would be promulgated no later than spring of 1995. 
    The suggested second phase of regulation could be developed through the 
    consultative process of regulatory negotiation. It could include issues 
    such as useful life, in-use emissions, evaporative emissions, refueling 
    emissions, test procedure, and market-based incentive programs. 
    Negotiations could begin in Fall 1993 and continue for approximately 18 
    months.
        EPA has decided to proceed with the phased approach. Today's action 
    proposes the first phase of regulation for new small SI engines. The 
    data that supports the proposed emission standards and the technology, 
    cost, and benefits assessments for this proposal are outlined herein 
    and in the draft Regulatory Support Document (RSD), a copy of which is 
    located in the public docket for this rulemaking. EPA does not 
    currently have sufficient data to establish useful life standards or an 
    in-use liability program. However, rather than lose the potential early 
    emission benefits while EPA develops the data necessary to establish 
    useful life and in-use liability, EPA is choosing to claim those early 
    benefits in this first phase of new small SI engine regulation and to 
    continue developing the data necessary for the second phase of small SI 
    engine regulation. EPA believes that the potential for early benefits 
    to public health and the environment provided by the first phase of 
    emission standards is of sufficient magnitude to postpone 
    determinations of useful life and in-use liability until the second 
    phase of rulemaking. The phased approach to regulation of small SI 
    engines is incorporated in the Sierra Club v. Browner settlement, a 
    copy of which is available in the public docket for this rulemaking.
    
    IV. Requirements of the Proposed Rule
    
        The general provisions of this rule, as well as the rationale for 
    the key parts of this proposal, are briefly described in the following 
    section.
    
    A. Overview
    
        EPA proposes to regulate emissions of hydrocarbons (HC), NOX, 
    and CO from certain new nonroad spark-ignition engines that have a 
    gross power output at and below 19 kW.\1\ A spark-ignition engine is an 
    internal combustion engine in which the air/fuel mixture is ignited in 
    the combustion chamber by an electric spark.
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        \1\To convert kilowatts to horsepower multiply kW by 1.34 and 
    round to the same number of significant digits. For example 3.5 
    kW x 1.34=4.7 hp.
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        The scope of this rule would encompass a broad range of small SI 
    engine applications, including farm and construction equipment, which 
    individual states are preempted from regulating under section 209(e)(1) 
    of the CAA. Exclusions from the rule are detailed below.
        Under this proposal, exhaust emissions from new small SI engines 
    could not exceed levels for a given engine class as listed in Table 1. 
    Engine classes would be specified both by engine displacement, as 
    measured in cubic centimeters (cc), and by the type of equipment the 
    engine powered--either handheld or nonhandheld. Five engine classes are 
    being proposed today. Each has a unique set of emission standards. 
    Nonhandheld engine classes would be: Class I--engines less than 225 cc 
    in displacement; and Class II--engines greater than or equal to 225 cc 
    in displacement. Engines powering equipment defined as handheld would 
    be classified as Class III, IV, or V: Class III--engines less than 20 
    cc in displacement; Class IV--engines equal to or greater than 20 cc 
    and less than 50 cc in displacement; and Class V--engines equal to or 
    greater than 50 cc in displacement. Emission standards being proposed 
    today are considered Phase 1 new small SI engine standards. 
    
                       Table 1--Exhaust Emission Standards                  
                            [Grams per kilowatt hour]                       
    ------------------------------------------------------------------------
                                Hydrocarbon                          Oxides 
           Engine class         plus oxides  Hydrocarbon   Carbon      of   
                                of nitrogen               monoxide  nitrogen
    ------------------------------------------------------------------------
    I.........................       16.1    ...........       402  ........
    II........................      113.4    ...........       402  ........
    III.......................  ...........        295         805      5.36
    IV........................  ...........        241         805      5.36
    V.........................  ...........        161         402      5.36
    ------------------------------------------------------------------------
    
        The rule would explicitly exclude from regulation the following 
    small SI engines:
        (1) Engines used to propel marine vessels as defined in the General 
    Provisions of the United States Code, 1 U.S.C. 3 (1992). A ``vessel'' 
    includes every description of watercraft or other artificial 
    contrivance used, or capable of being used, as a means of 
    transportation on water. 1 U.S.C. 3 (1992).
        (2) Engines used in underground mining or engines used in 
    underground mining equipment and regulated by the Mining Safety and 
    Health Administration (MHSA). See 30 CFR parts 7, 31, 32, 36, 56, 57, 
    70, and 75.
        (3) Engines used in motorcycles and regulated in 40 CFR part 86, 
    subpart E.
        (4) Engines used in aircraft as that term is defined in 40 CFR 
    87.1(a).
        (5) Engines used in recreational vehicles, which are defined as 
    engines which have no installed speed governor and which have a rated 
    speed of greater than or equal to 5,000 revolutions per minute (RPM). 
    Engines used in recreational vehicles are not used to propel marine 
    vessels and do not meet the criteria to be categorized as a Class III, 
    IV, or V engine under this rule.
        This rule proposes the following regulatory scheme:
         Designation of product lines into groups of engines with 
    similar emission characteristics (such groups are called engine 
    families),
         Manufacturer emission testing of selected engines with a 
    specified test procedure to demonstrate compliance with new engine 
    emission standards,
         Labeling of engines, and alternatively, equipment labeling 
    if the engine label becomes obscured when placed in the equipment,
         Submission of an application for certification for each 
    engine family,
         Inclusion of various certification requirements such as 
    the prohibition of defeat devices,
         Issuance of an emission certificate of conformity for each 
    engine family,
         Prohibition against offering for sale in the United States 
    engines not certified by EPA,
         Requirement that equipment manufacturers use the 
    appropriate handheld or nonhandheld certified engine in their 
    equipment,
         Recordkeeping and reporting requirements,
         EPA Administrator testing provisions,
         Design warranty provisions and prohibition on tampering,
         Inclusion of all farm and construction engines, state 
    regulation of which is preempted under the CAA,
         Development of an engine manufacturer's program to 
    evaluate in-use emission deterioration,
         Requirement that if catalysts are used in an engine 
    family, catalyst durability must be confirmed by means of the 
    evaluation procedure that is specified in this notice,
         Defect reporting and voluntary recall,
         Importation provisions,
         General prohibitions and enforcement provisions, and
         Production line Selective Enforcement Auditing (SEA). 
    Certain elements of EPA's on-highway program are not being proposed for 
    this Phase I rule including:
         No certification requirement for engine durability 
    demonstration,
         No performance warranty,
         No averaging, banking, and trading program, and
         No useful life determination and no in-use enforcement.
    
    B. General Enforcement Provisions
    
        EPA, as authorized in the CAA, would enforce nonroad standards in a 
    manner similar to on-highway standards. Section 213(d) of the Act 
    provides that the standards promulgated under 213 ``shall be subject to 
    sections (206, 207, 208, and 209), with such modifications of the 
    applicable regulations implementing such sections as the Administrator 
    deems appropriate, and shall be enforced in the same manner as 
    standards prescribed under section (202).'' Section 206 specifies 
    requirements for motor vehicles and motor vehicle engine compliance 
    testing and certification; section 207 requires manufacturers to 
    warrant compliance by motor vehicles and motor vehicle engines in 
    actual use; section 208 requires recordkeeping by manufacturers of new 
    motor vehicles or new motor vehicle engines and authorizes EPA to 
    collect information and require reports; and section 209 preempts 
    states and political subdivisions from adopting or enforcing standards 
    relating to emission control, certification, or inspection of new motor 
    vehicles or new motor vehicle engines, unless specifically authorized 
    to do so by EPA.
        Pursuant to this authority, EPA is proposing in today's action 
    regulations that require manufacturers of new small SI engines to 
    obtain certification and that subject them to Selective Enforcement 
    Auditing. Any manufacturer of a new small SI engine would be 
    responsible for obtaining from the Administrator a certificate of 
    conformity covering any engine introduced into commerce in the United 
    States.
        The Agency is also proposing certain prohibited acts and general 
    enforcement provisions similar to those for on-highway vehicles under 
    sections 203, 204, 205, and 208 of the CAA.
        Section 203 specifies prohibited acts; section 204 provides for 
    federal court injunctions of violations of section 203(a); section 205 
    provides for assessment of civil penalties for violations of section 
    203; and section 208 provides the Agency with information collection 
    authority. The general enforcement language of section 213(d) provides 
    the Agency's authority for applying section 203, 204, 205, and 208 of 
    the CAA to new small SI engines and equipment.
        As applied to nonroad engines, vehicles and equipment under section 
    213(d), Phase 1 prohibited acts would include, but would not be limited 
    to:
         An engine manufacturer's introduction into commerce of new 
    small SI engines that are not covered by a certificate of conformity 
    issued by EPA,
         The introduction into commerce of new small SI equipment 
    and vehicles which do not incorporate the appropriate nonhandheld or 
    handheld certified nonroad engine,
         Tampering with emission control devices or elements of 
    design installed on or in a small SI engine, and
         Failure to provide information to the Agency if requested.
    
    EPA is also proposing regulations, under the authority of section 205 
    of the Act, which set forth the maximum statutory penalties for 
    violating the prohibitions.
        EPA is proposing general information collection provisions similar 
    to current on-highway provisions under section 208 of the Act which 
    would include, but would not be limited to, the manufacturer's 
    responsibility to provide information to EPA, perform testing if 
    requested by EPA, and maintain records. In addition, EPA is proposing 
    emission system defect reporting regulations which require 
    manufacturers to report to EPA emission system-related defects that 
    affect a given class or category of engines. EPA enforcement personnel 
    would be authorized to gain entry and access to various facilities 
    under section 208 and today's action proposes these entry and access 
    provisions.
        This rule's information requirements are similar to those proposed 
    in the nonroad large compression-ignition (CI) rule,\2\ but reduced 
    from the on-highway program requirements. EPA requests comment on 
    whether patterning the small SI engine information requirements after 
    the nonroad large CI rule is appropriate for the manufacturers of small 
    nonroad engines. In particular, EPA request comments on whether there 
    are more efficient or more effective ways than those proposed for 
    manufacturers to create, maintain, and report this information; whether 
    electronic data interchange (EDI) is a common practice within this 
    industrial sector; and whether EPA should consider using EDI or any 
    other technology in its information collection to reduce the burden and 
    costs of compliance.
    ---------------------------------------------------------------------------
    
        \2\See Control of Air Pollution; Emissions of Oxides of Nitrogen 
    and Smoke From New Nonroad Compression-Ignition Engines at or above 
    50 Horsepower, 58 FR 28809 and 51595 (May 17, 1993).
    ---------------------------------------------------------------------------
    
        EPA is authorized under section 217 of the CAA to establish fees to 
    recover compliance program costs associated with section 206 and 207. 
    EPA will propose to establish fees for today's nonroad compliance 
    program at some future time, after this rule has been promulgated and 
    associated costs are determined.
    
    C. Program Description and Rationale
    
        This section describes several features of EPA's proposed Phase 1 
    small SI engine, vehicle and equipment compliance program and EPA's 
    rationale for including these features in the program. Specific issues 
    related to the proposed program which require in- depth discussion are 
    presented in ``V. Discussion of Issues.''
    1. Applicability
        This rule would apply to new nonroad spark-ignition engines that 
    have a gross power output at or below 19 kW and are manufactured after 
    August 1, 1996 for use in the United States. New engines that would be 
    covered by this rule are used in a large and varied assortment of 
    vehicles and equipment including lawnmowers, string trimmers, edgers, 
    chain saws, commercial turf equipment, small construction equipment, 
    and lawn and garden tractors.
        EPA estimates that in the first year of regulation approximately 
    16,525,000 new engines, or approximately 19.4 percent of the in-use 
    fleet, would be subject to this regulation. See Chapter 4 of the draft 
    Regulatory Support Document (hereafter, draft RSD) for this 
    rulemaking.\3\
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        \3\A copy of the draft RSD may be found in the docket for this 
    rulemaking.
    ---------------------------------------------------------------------------
    
        EPA is proposing to require certification of new small SI engines, 
    not the vehicle or equipment which houses such engines. First, small SI 
    engines are used in a variety of applications. EPA believes it is 
    inappropriate to mandate that a specific SI engine be manufactured for 
    any given application. Second, the number of manufacturers and the 
    diversity of vehicles and equipment in which small SI engines are used 
    would present clear administrative problems. Regulating primarily by 
    vehicle or equipment type would dramatically increase administrative 
    cost associated with this rule with no comparable reduction in 
    emissions. EPA is, however, proposing to require that vehicle and 
    equipment manufacturers and importers use the appropriate certified 
    nonroad engines in their vehicles and equipment. This requirement is 
    discussed in ``V.H. Requirements Applicable to Vehicle and Equipment 
    Manufacturers.''
        EPA also considered, but rejected, the idea of including SI engines 
    above 19 kW in this Phase 1 rule. Engines above the proposed 19 kW 
    cutoff tend to exhibit different operating cycle characteristics than 
    small SI engines. This difference necessitates the development of 
    additional test procedures. EPA does not have sufficient data to 
    undertake such a development within the timeframe of this Phase 1 rule. 
    As part of the Sierra Club v. Browner settlement, EPA will determine by 
    November 1996 whether to undertake a rulemaking which targets emissions 
    from SI engines over 19 kW.
        Certain small SI engines which otherwise would be subject to this 
    rule would be explicitly excluded from regulation:
        (1) Engines used to propel marine ``vessels'' as such term is 
    defined in 1 U.S.C. 3 (1992). EPA is not including these engines 
    because they are currently subject to safety regulations by the U.S. 
    Coast Guard (See 46 U.S.C. 331 and 46 U.S.C. 4302.), and EPA is 
    developing a separate rulemaking which will propose appropriate methods 
    of regulating emissions from these engines.
        (2) Engines regulated by the Mining Safety and Health 
    Administration (MSHA) for underground use. EPA is not including in this 
    proposal engines that are used in underground mining or engines used in 
    underground mining equipment as regulated by MSHA under the authority 
    of 30 CFR parts 7, 31, 32, 36, 56, 57, 70, and 75. MSHA is responsible 
    for protecting miners from unhealthy levels of air pollution in 
    underground mines and has issued air quality standards for mines and 
    standards for NOX and CO emissions from some types of mining 
    equipment. Although EPA considered applying EPA regulations to these 
    engines, EPA chose not to include them at this time in order to avoid 
    dual regulation of these engines.
        (3) Engines used in motorcycles and regulated in 40 CFR part 86, 
    subpart E. EPA has regulated emissions from motorcycles since 1978. A 
    motorcycle means any motor vehicle with a headlight, taillight, and 
    stoplight and having two wheels or three wheels and a curb mass less 
    than or equal to 680 kilograms.
        (4) Engines used in aircraft as that term is defined in 40 CFR 
    87.1(a).
        (5) Engines used in recreational vehicles which are defined as 
    follows: (1) The engine has no installed speed governor; (2) the 
    engine's rated speed is greater than or equal to 5,000 RPM; (3) the 
    engine is not used for the propulsion of a marine vessel; and (4) the 
    engine does not meet the criteria to be categorized as a Class III, IV, 
    or V engine under this regulation. Recreational vehicles include: All-
    terrain vehicles, off-road motorcycles, snowmobiles, and go-karts. 
    These engines are being excluded for several reasons: First, the duty 
    cycle is completely different from most small SI engine applications. 
    These engines experience highly transient operation and likely will 
    require completely different test procedures for purposes of emission 
    control testing. Second, they are designed to emphasize power output; 
    thus, they are typically designed to run at much higher RPMs than other 
    small SI engines. EPA invites comments on other criteria which may be 
    utilized in defining the class of nonroad engines which propel 
    recreational vehicles.
    2. Exclusions and Exemptions to Today's Proposal
        Pursuant to section 203(b)(1) of the CAA, the Agency is proposing 
    additional categories of exemptions from new small SI engine regulation 
    similar to the exclusions and exemptions that exist for on-highway 
    engines and that have been proposed in the nonroad large CI engine 
    rule. These include exemptions for purposes of research, 
    investigations, studies, demonstrations, training, or for reasons of 
    national security. Exemptions would be obtained either categorically, 
    that is without application to the Administrator, or by submitting a 
    written application to the Administrator. Export exemptions and 
    manufacturer-owned engine exemptions would be granted without 
    application. Testing exemptions, display exemptions, and national 
    security exemptions would be obtained by application.
        Exclusions from this regulation include nonroad engines that are 
    used solely for competition or for combat.
        Exemptions and exclusions are justified in these cases because the 
    sources are limited in number or scope, so minimal environmental harm 
    results; the particular use of the source is determined to further air 
    quality research; and/or the exemption is vital to the security of the 
    nation. (See 39 FR 10601, March 21, 1974.)
    3. Effective Date for Certification
        EPA is proposing that certification of new small SI engines begin 
    in 1996. Manufacturers of engines produced on or after August 1, 1996, 
    would be required to obtain from the Administrator a certificate of 
    conformity covering the engine family. The certificate would be 
    obtained prior to selling, offering for sale, introducing into 
    commerce, or importing into the United States the new engine.
        While the small SI engines affected by this proposal include a 
    broad range of engine types, EPA believes that the effective date for 
    the proposed standards is reasonable and technologically feasible and 
    that engine manufacturers will be able to implement these regulations 
    within the short lead time provided under this rule. This issue is 
    discussed, in detail, in ``V.I. Effective Date.'' Further, an August 1, 
    1996 effective date is consistent with the Congressional mandate found 
    in section 213(c) of the Clean Air Act which requires that, ``Standards 
    * * * shall take effect at the earliest possible date considering lead 
    time necessary to permit the development and application of the 
    requisite technology * * *''
    4. Emission Standards
        Section 213(a)(3) of the CAA states that nonroad emissions 
    standards:
    
        * * * shall achieve the greatest degree of emission reduction 
    achievable through the application of technology which the 
    Administrator determines will be available for the engines or 
    vehicles to which such standards apply, giving appropriate 
    consideration to the cost of applying such technology within the 
    period of time available to manufacturers and to noise, energy, and 
    safety factors associated with the application of such technology. 
    In determining what degree of reduction will be available, the 
    Administrator shall first consider standards equivalent in 
    stringency to standards for comparable motor vehicles or engines (if 
    any) regulated under section 7521 of this title, taking into account 
    the technological feasibility, costs, safety, noise, and energy 
    factors associated with achieving, as appropriate, standards of such 
    stringency and lead time * * *.
    
    The emission standards being proposed for this Phase 1 small engine 
    regulation are listed in Table 1 in the Overview Section. The proposed 
    emission standards result in significant emission reductions in the 
    near term while work is going on to develop more stringent Phase 2 
    standards and while manufacturers work to design engines and equipment 
    capable of meeting lower standards at a later date.
        EPA believes these proposed emission standards represent the 
    greatest emission reductions achievable given the short lead time prior 
    to this rule's effective date and the technology available during this 
    period. Requiring more stringent Phase 1 emission standards than those 
    proposed today would necessarily delay implementation of new small SI 
    engine standards by at least two years. This additional lead time would 
    be needed to allow manufacturers time to redesign engines and equipment 
    to accommodate requirements of more sophisticated technologies. Air 
    quality benefits which will accrue under the proposed emission 
    standards are large and meet the statutory criteria for nonroad 
    standards required by the CAA. These benefits are discussed in Section 
    VI of this preamble.
        In determining the appropriate level of emission standards to 
    propose, EPA initially considered, as required in the CAA, comparable 
    motor vehicle standards. Due to technological constraints present in 
    small engines, EPA believes that promulgating emission standards 
    comparable with motor vehicle standards in a Phase 1 rule is not 
    technologically achievable. See chapter 1 of the draft RSD for further 
    discussion of small SI engine technological constraints.
        In proposing these emission standards, EPA has also considered 
    potential safety and noise issues. Of concern is 36 CFR 261.52 which 
    directs the Forest Service to prohibit the operation or use of any 
    handheld internal or external combustion engine without a spark-
    arresting device properly installed, maintained, and in effective 
    working order. The Forest Service also requires that multipositional 
    small engines used on federal park lands have exposed exhaust system 
    surface temperatures not exceeding 550  deg.C. Exhaust gas temperatures 
    may not exceed 475  deg.C.
        The type of engine changes EPA expects as a result of the proposed 
    emission standards will not present a safety concern. Only catalytic 
    converters designed to produce high conversion efficiencies can 
    generate sufficient exotherms to raise exhaust system skin temperatures 
    to a level that might present a safety problem. Manufacturers have 
    indicated that they will not use catalytic converters to meet the 
    proposed emission standards for most product lines. EPA estimates that 
    up to 30 percent of engines in Class I may need low efficiency 
    catalysts to meet the standards. However, one manufacturer stated that 
    the exotherm generated by these low efficiency catalysts will not 
    affect exhaust system skin temperatures sufficiently to warrant more 
    advanced heat dissipation and heat shield technologies.
        Noise levels of small SI engines will not be allowed to increase as 
    a result of the proposed emission standards. The type of engine changes 
    EPA expects to see among current engine designs to meet the proposed 
    emission standards are not expected to impact noise levels. The primary 
    source of noise from nonroad small engines originates from combustion 
    and the moving parts in the engine, such as the piston, valve train, 
    and so forth. Noise from combustion is controlled primarily through the 
    engine muffler. EPA believes the principal method to be used by all 
    engine manufacturers to meet the proposed emission regulation will be 
    leaner air/fuel ratios. Noise levels in future engines which meet the 
    proposed regulations must, therefore, not exceed that of current 
    production engines.
        EPA requests comment on the possible impact of this proposed 
    regulation on both engine noise and safety.
        In EPA's judgment, section 213(a)(3)'s requirement that EPA 
    regulate emissions from those classes or categories of new nonroad 
    engines which cause, or contribute to concentrations of ozone in 
    nonattainment areas allows EPA to set emission standards for HC, rather 
    than VOCs in general, as EPA believes that HC emissions from small 
    gasoline engines are those that cause or contribute to ozone 
    nonattainment concentrations. In addition, regulating HC rather that 
    VOCs would be consistent with on-highway practice. EPA requests comment 
    on this proposed approach.
        In the Nonroad Study, EPA described VOCs as any compounds 
    containing carbon and hydrogen or containing carbon and hydrogen in 
    combination with any other element which has a vapor pressure of 1.5 
    pounds per square inch absolute or greater under actual storage 
    conditions.
        HCs contain both hydrogen atoms and carbon atoms but no other atoms 
    and are a subset of VOCs. For small SI engines, based on engines tested 
    by Southwest Research Institute under contract with EPA, HCs make up 
    more than 99 percent of the VOCs emitted from these engines. Less than 
    one percent of the measured VOC emissions are from constituents other 
    than HC emissions (aldehydes and ketones were the measured non-
    hydrocarbon constituents in this case).
        In general, the types of emission controls employed to reduce HC 
    emissions also reduce emissions of non-hydrocarbon VOCs. Therefore, in 
    the case of small SI engines, setting emission limits for HC emission 
    accomplishes essentially the same overall reduction in VOC emission as 
    would setting emission limits for VOCs. Of course reductions in the 
    individual non- hydrocarbon VOC species varies, as does the individual 
    hydrocarbon species.
    5. Engine Classes
        The category of small SI engines is very complex and comprises a 
    wide range of engines used in a broad spectrum of equipment. EPA 
    proposes to adopt a ``class'' structure for this Phase 1 regulation. In 
    determining which class of emission standards a particular engine must 
    meet, an engine's end use or application must be determined. This rule 
    proposes two broad use categories--nonhandheld and handheld. 
    Nonhandheld engines would be required to meet either Class I or Class 
    II standards while handheld engines would have to meet either Class 
    III, IV, or V emission standards. Once the applicable use category is 
    determined, the engine class would be selected on the basis of engine 
    displacement as measured in cubic centimeters (cc).
        Each engine class would have unique emission standards. EPA is 
    proposing five engine classes: Class I--small nonhandheld engines less 
    than 225 cc in displacement; Class II--small nonhandheld engines 
    greater than or equal to 225 cc in displacement; Class III--small 
    handheld engines less than 20 cc in displacement; Class IV--small 
    handheld engines equal to or greater than 20 cc to less than 50 cc in 
    displacement; Class V-- small handheld engines equal to or greater than 
    50 cc in displacement.
        Class I engines are overwhelmingly found in lawnmowers. Class II 
    engines primarily include engines used in generator sets, garden 
    tractors, and commercial lawn and garden equipment.
        Only engines used in equipment defined as handheld would be allowed 
    to meet Class III, IV, or V emission standards. Class III includes 
    engines used in consumer handheld products, such as small string 
    trimmers, edgers, and brush cutters. Class IV encompasses engines used 
    in both residential and commercial settings and includes large 
    trimmers, edgers, blowers, and chain saws. Class V includes a majority 
    of engines utilized in commercial chain saws.
        EPA is proposing five separate engine classes based on a number of 
    factors. First, some types of equipment are currently powered 
    exclusively by 2-stroke engines. EPA estimates that as much as 90 
    percent of 2-stroke engines are utilized in handheld equipment. These 
    current handheld 2-stroke engines incorporate a technology which is 
    inherently more polluting than current 4-stroke engine technology and 
    which results in 2-stroke engines experiencing a higher concentration 
    of hydrocarbons in their exhaust. EPA's view is that it is not 
    technologically feasible to apply the nonhandheld Class I and II engine 
    standards to handheld engines in this Phase 1 rule; therefore the need 
    arises for Class III, IV, and V handheld engine standards. Differences 
    in stringency between classes III, IV, and V are due to the fact that 
    energy-specific emissions generally increase as engine size decreases. 
    This principle is also true in the case of engines used in nonhandheld 
    applications and meeting emission standards of either classes I or II. 
    See discussion in the draft RSD. Finally, the engine classification 
    approach for Phase 1 harmonizes federal small engine regulations with 
    California's lawn and garden regulations.
        In summary, it is EPA's view that the emission standards proposed 
    today for handheld and nonhandheld engines and reflected in the five 
    engine class categories represent the greatest emission reduction 
    achievable for this Phase 1 rule.
    6. Handheld Engine Qualifications
        To qualify as a handheld engine under this proposal, the small SI 
    engine would be required to meet at least one of the following three 
    requirements:
        (1) The engine must be used in a piece of equipment that is carried 
    by the operator throughout the performance of its intended function(s). 
    This is meant to encompass such equipment as lightweight leafblowers, 
    trimmers (both string and hedge), and cutters.
        (2) The engine must be used in a piece of equipment that must 
    operate multipositionally, such as upside down and sideways, to 
    complete its intended function(s). EPA intends this category to include 
    all types of chain saws as well as items already listed in the first 
    requirement.
        (3) The engine must be used in a piece of equipment for which the 
    combined engine and equipment dry weight is under 14 kilograms, no more 
    than two wheels are present, and at least one of the following 
    attributes is also present:
        (a) The operator must alternately provide support or carry the 
    equipment throughout the performance of its intended function(s). This 
    allows lightweight snowblowers that are carried up stairs, or edgers 
    which are picked up and supported during operation to qualify for 
    handheld status.
        (b) The operator must provide support or attitudinal control for 
    the equipment throughout the performance of its intended function(s). 
    This attribute will allow equipment such as lightweight tillers, 
    augers, cutoff/concrete saws, and edgers to qualify for handheld 
    status.
        (c) The engine is used exclusively in a hand-portable generator or 
    pump.
        For purposes of this section ``support'' would mean that the 
    operator holds the equipment in position so as to prevent it from 
    falling, slipping, or sinking. It would not be necessary for the entire 
    weight of the equipment to be borne by the operator. ``Attitudinal 
    control'' would mean that the operator regulates either the horizontal 
    or vertical position of the equipment, or both. ``Carry'' would mean 
    that the operator completely bears the weight of the equipment, 
    including the engine.
        Section ``V.G. Definition of Handheld Engines'' provides additional 
    discussion on this issue. EPA believes that this proposed handheld 
    definition adequately covers those categories of engines which should 
    be allowed to meet the less stringent handheld engine standards.
        EPA requests information regarding specific engine applications 
    which are not clearly identifiable as handheld or nonhandheld under the 
    proposed definition. EPA also requests alternative language which could 
    be incorporated in this definition to clarify the distinction between 
    handheld and nonhandheld. EPA is particularly concerned that 
    manufacturers of 2-stroke lawnmowers may attempt to qualify for 
    handheld status utilizing the second requirement--multiposition 
    operation. It is not EPA's intent that pushing a lawnmower up and down 
    hills would qualify as multiposition operation.
    7. Standards for Classes I and II
        EPA is proposing to adopt one of two options under consideration 
    for setting standards applicable to Class I and II engines. EPA 
    requests comments on each of these options.
        Option 1: Phase 1 would adopt a combined HC + NOX standard for 
    engine classes I and II. While engines in classes I and II have high HC 
    emission rates, most currently produce extremely low levels of 
    NOX. Due to technological constraints of all small SI engines, HC 
    reductions would generally come at the expense of increased NOX. 
    See ``VII. Technology Assessment'' for a discussion of this phenomenon. 
    However, the resultant overall increase in NOX emission 
    inventories would be slight relative to the NOX produced by 
    sources such as nonroad large CI engines. The sensitivity of NOX 
    emissions to HC control varies greatly between engine designs. EPA 
    believes that a Phase 1 approach which allows incremental tradeoffs 
    between HC and NOX controls through a combined standard would be 
    consistent with EPA's statutory mandate that nonroad engine emission 
    standards reflect the greatest emission reductions achievable. See 
    ``VII. Technology Assessment'' for further discussion.
        To meet the combined standard, a manufacturer would add its HC 
    emission test result to the NOX test result. This combined number 
    would then be submitted to EPA. Individual levels of these pollutants 
    would not be established. The manufacturer would also be required to 
    meet this combined level during Administrator testing and the SEA 
    enforcement program. EPA believes that this approach would be workable 
    for a Phase 1 rule. Setting separate standards for HC and NOX 
    would be addressed in EPA's Phase 2 regulatory negotiations. For 
    further discussion of this issue, see ``V. M. HC + NOX Standard 
    for Class I, II Engines.''
        EPA is reluctant to set such a combined standard because it is 
    extremely concerned that no precedent be set for promulgating combined 
    emission standards in future rulemakings. EPA's past practice has been 
    to set separate pollutant standards. EPA is considering the combined 
    standard approach only for this Phase 1 small SI engine rule because of 
    limited data availability, the aggressive timeframe of this rule, and 
    to harmonize with the California lawn and garden regulation.
        Option 2: Under this option EPA would set separate Class I and II 
    emission levels for HC and NOx. Based on information currently 
    available to EPA, the NOx standard would be approximately 136 percent 
    higher than current new engine levels, while the HC standard would be 
    approximately equal to the difference between those levels and the HC + 
    NOx standards proposed in option 1. EPA requests comment on this 
    specific option, including industry data which addresses the 
    appropriate level of both HC and NOx if separate standards were to be 
    promulgated.
    8. Engine Family Categorization
        For the purpose of demonstrating emission compliance, EPA is 
    proposing that manufacturers of small SI engines divide their product 
    line into groups of engines, called engine families, which are composed 
    of engines having similar emission characteristics. Small SI engine 
    families would be determined by using the same criteria (type of fuel, 
    method of air aspiration, number of cylinders, and so forth) currently 
    used to define on-highway motorcycle engine families.
        To be placed in the same engine family, engines would be required 
    to be identical in all the following applicable respects:
        (1) Combustion cycle,
        (2) Cooling mechanism,
        (3) The cylinder configuration (inline, vee, opposed bore spacings, 
    and so forth),
        (4) The number of cylinders,
        (5) The engine class,
        (6) The number of catalytic converters (location, volume, and 
    composition), and
        (7) The thermal reactor characteristics.
        At the manufacturer's option, engines identical in all the above 
    respects could be further divided into different engine families if the 
    Administrator determined that such engines were expected to have 
    different emission characteristics. This determination would be based 
    on a number of features, such as the intake and exhaust valve or port 
    size, the fuel system, exhaust system, and method of air aspiration.
        EPA requests comment on the appropriateness of adding governed 
    engine RPM range as a criterion for the determination of an engine 
    family. EPA is concerned that a wide-governed RPM spread in the same 
    engine family, that is one engine configuration has a no-load governed 
    speed at 3,200 RPM and another engine configuration has a rated no-load 
    governed speed of 2,200 RPM, may be a sufficient reason to break up one 
    engine family into more than one engine family.
    9. Compliance With Emission Standards
        The test engine(s) representing an engine family would be required 
    to demonstrate that emissions are less than or equal to each separate 
    emission standard. If a test engine exceeded any one emission standard 
    in the applicable class, the engine family would be deemed not in 
    compliance with emission standards of that class.
        EPA is proposing that if catalysts are used in an engine family to 
    meet the emission standards of this regulation, the engine manufacturer 
    must affirm that the durability of the catalysts has been confirmed on 
    the basis of the evaluation procedure that is specified in this notice.
    10. Useful Life Period, In-use Enforcement, and Development of an In-
    use Testing Program
        EPA is not proposing a small SI engine useful life period or an in-
    use enforcement program in today's proposal. However, EPA believes that 
    a critical element in the success of its nonroad program is assuring 
    that manufacturers build engines that continue to meet emission 
    standards throughout the engine's useful life. While section 213(d) of 
    the CAA authorizes EPA to enforce emission standards in-use, EPA is 
    proposing to postpone setting a useful life period and an in-use 
    enforcement program for small SI engines until the Phase 2 regulations 
    become effective and, instead, to require in this Phase 1 regulation 
    that manufacturers test in-use engines. The Phase 2 rulemaking for 
    small SI engines is under a court-ordered deadline and must be 
    promulgated by April 30, 1997.
        EPA is not proposing a Phase 1 useful life period for several 
    reasons. Only limited testing data is currently available on in-use 
    performance of small SI engines. Additional data would be provided by 
    the in-use testing program described below. Second, EPA does not 
    believe that emission controls proposed for Phase 1 will experience 
    significant deterioration beyond normal engine deterioration, although 
    this area needs more research. For further discussion of these issues 
    see ``V.P. Applicability of In-Use Standards'' and ``V.Q. In-Use 
    Testing Requirements.''
        The proposed in-use testing requirement is intended to parallel in-
    use testing previously or currently conducted by industry. While 
    manufacturers and their associations have proposed that EPA adopt a 
    cooperative testing program, EPA believes cooperative programs would 
    not adequately or as effectively achieve the goals of this in-use 
    program. See ``V.Q. In-Use Testing Requirements.''
        EPA is proposing that engine manufacturers test a sample of in-use 
    engines. In the absence of in-use emission standards, EPA believes this 
    testing requirement would be invaluable for manufacturers and EPA to 
    learn about in-use emissions and emission deterioration. Although EPA 
    would not enforce in-use emission standards for Phase 1 engines, EPA 
    expects that manufacturers would take appropriate actions to prevent 
    recurrence of in-use noncompliance and to also remedy in-use 
    noncompliance when it was discovered.
        At the time of certification the engine manufacturer would propose 
    which engine families are to be included in the in-use test program. 
    The certificate of conformity issued by EPA for engine families 
    included in the in-use testing program would be conditional based on 
    completion of the test program for that family. EPA would approve a 
    manufacturer's test program if the selected engine families represented 
    an adequate consideration of the elements discussed below.
        Number of engines to be tested: The number of small SI engines to 
    be tested by a manufacturer would be determined by the following 
    method:
        For an engine manufacturer with total projected annual production 
    of more than 75,000 small SI engines, the minimum number of engines to 
    be tested will be the lowest of the numbers determined in (1), (2), or 
    (3) below:
        (1) Divide the manufacturer's total projected annual production of 
    small SI engines by 50,000, and round to the nearest whole number,
        (2) Test five engines each from 25 percent of all small SI engine 
    families certified in that model year,
        (3) Test three engines each from 50 percent of all small SI engine 
    families certified in that model year.
        An engine manufacturer with total projected annual production of 
    75,000 small SI engines or less must test a minimum of two engines.
        Criteria for selecting test engines: An engine manufacturer would 
    be required to select test engines from engine families utilizing the 
    following criteria and in the order specified:
        (1) Engine families using emission technology which may be used on 
    phase 2 engines,
        (2) Engine families using aftertreatment,
        (3) Engine families certified to different emission standards,
        (4) Different engine designs (such as side valve versus overhead 
    valve engines),
        (5) Engine families using emission control technology specifically 
    installed to achieve compliance with Phase 1 standards,
        (6) The engine family with the highest projected annual sales, and
        (7) Engine families which meet the above criteria, but have not 
    been included in prior model year in-use testing programs as required 
    by these provisions.
        Collection and testing of in-use engines: An engine manufacturer 
    would be required to procure in-use engines which have been operated 
    for between half and three-quarters of the engine's advertised (or 
    projected) useful life. All testing would be completed within three 
    years after the certificate is issued or is effective, whichever is 
    later, for an engine family which requires in-use testing.
        A test engine would be procured from sources not associated with 
    the engine manufacturer or equipment manufacturer, except that, with 
    prior approval of the Administrator, an engine manufacturer with annual 
    sales of less than 50,000 engines might obtain in-use engines 
    associated with itself or its equipment manufacturer.
        A test engine would be required to have a maintenance history 
    representative of actual in-use conditions. To comply with this 
    requirement a manufacturer would question the end user regarding the 
    accumulated usage, maintenance, operating conditions, and storage of 
    the test engine.
        The manufacturer would perform minimal set-to-spec maintenance on a 
    test engine. Maintenance would include only what is listed in the 
    owner's instructions for engines with the amount of service and age of 
    the acquired test engine. One valid emission test would be required for 
    each in-use engine. Finally, if a selected in-use engine failed to 
    comply with any applicable certification emission standards, the 
    manufacturer would be responsible for determining the reason for 
    noncompliance.
        In-use test program reporting requirements: The manufacturer would 
    be required to submit to the Administrator by January 30 of each 
    calendar year all emission testing results generated from the in-use 
    testing program. At the Administrator's request, a manufacturer would 
    be required to provide documents used in the procurement process, 
    including criteria used in the procurement screening process and 
    information from the end user(s) related to use, maintenance, and 
    storage of the selected engines.
        EPA is aware that engine manufacturers may have near-term concerns 
    regarding testing capacity and the burden this type of program may 
    impose on a newly regulated industry. EPA requests comments on the lack 
    of in-use standards, the lack of in-use enforcement, all elements of 
    this proposed testing requirement, and on possible alternative designs 
    of in-use testing programs (such as a joint program between 
    manufacturers and EPA) or enforcement that may be more effective, 
    giving consideration to the limited lead time and duration of the Phase 
    1 program.
    11. Certificate of Conformity, Requirements of Certification
        Any manufacturer of a small SI engine would be responsible for 
    obtaining from the Administrator a certificate of conformity covering 
    any engine introduced into commerce in the United States, before such 
    an engine is sold, offered for sale, introduced or delivered for 
    introduction into commerce, or imported into the United States.
        Section 203 of the CAA does not prohibit the production of vehicles 
    or engines before a certificate of conformity is issued. Vehicles or 
    engines produced prior to the effective date of a certificate of 
    conformity might also be covered by the certificate if the following 
    conditions were met:
         The engine conformed in all respects to the engines 
    described in the application for the certificate of conformity.
         The vehicles or engines were not sold, offered for sale, 
    introduced into commerce, or delivered for introduction into commerce 
    prior to the effective date of the certificate of conformity.
         The Agency was notified prior to the beginning of 
    production when such production would start, and the Agency was 
    provided full opportunity to inspect and/or test the engines during and 
    after their production. For example, the Agency would have the 
    opportunity to conduct SEA production line testing as if the engines 
    had been produced after the effective date of the certificate.
        EPA is proposing that a number of requirements be met by the engine 
    manufacturer prior to granting a certificate of conformity. As is the 
    case for on-highway vehicles and engines, the proposed regulations 
    would make it illegal for any person to use a device on a nonroad 
    engine which senses operation outside normal emission test conditions 
    and reduces the ability of the emission control system to control the 
    engine's emissions. To guard against use of these devices, EPA would 
    reserve the right to require testing of a certification test engine 
    over a modified test procedure if EPA suspected a defeat device was 
    being used by an engine manufacturer on a particular engine. In 
    addition, use of defeat devices would be considered a prohibited act 
    subject to civil penalties.
        Engines equipped with adjustable operating parameters would have to 
    comply with all the regulations with the parameters adjusted to any 
    setting in the full range of adjustment. For example, this could 
    include adjustment of the high-speed needle for alteration of the air/
    fuel ratio or adjustment of the speed set screw. This would ensure that 
    changes to the adjustable operating parameters that might readily occur 
    in use would not cause the engine to fail to comply with these 
    regulations.
        EPA is proposing to require that manufacturers label each engine 
    and that the label meet the same requirements with respect to 
    durability and visibility as required in the current on-highway 
    program. The engine manufacturer would be responsible for proper 
    labeling of engines from each engine family. In addition, EPA is 
    proposing labeling requirements for vehicle and equipment manufacturers 
    if the engine label is obscured.
        EPA is also proposing that each engine must have a unique engine 
    identification number which may be part of the engine label or engraved 
    on the engine. Such identification is necessary for tracking individual 
    engines. Use of engine identification numbers would facilitate setting 
    up a tracking system and allow manufacturers to sample in-use engines 
    for their programs. This identification would be essential for 
    development of a long-term in-use durability program. EPA requests 
    comment on the labeling proposal as well as on current engine 
    identification practices within the industry.
        Finally, EPA also proposes to require that all engine crankcases 
    must be closed to preclude the emissions that occur when a crankcase is 
    vented to the atmosphere. Since most currently produced engines do have 
    closed crankcases, EPA believes this requirement would impact 
    relatively few manufacturers. Finally, small SI engine noise levels 
    would not be allowed to increase as a result of this rule.
        EPA requests comment on these proposed certification requirements. 
    While EPA is today proposing vehicle and equipment manufacturer 
    labeling responsibilities, EPA is considering whether to instead make 
    engine manufacturers responsible for ensuring that the emission control 
    label is visible once the certified engine is incorporated into a given 
    piece of nonroad equipment. EPA requests comment on this specific issue 
    as well.
    12. Vehicle/Equipment Manufacturer Requirements
        Commencing on this rule's effective date, manufacturers of small SI 
    vehicles and equipment and importers would be prohibited from 
    introducing into U.S. commerce any vehicle or equipment powered by a 
    small SI engine which does not incorporate the appropriate certified 
    handheld or nonhandheld engine. Failure to do so would make the 
    equipment manufacturer liable for the assessment of civil penalties. 
    EPA is proposing this requirement because it is concerned that engines 
    certified to meet handheld engine standards may in fact be used in 
    nonhandheld equipment. This would significantly and negatively impact 
    air quality benefits which are to accrue as a result of this rule. Due 
    to the potential for engines in different categories to be substituted 
    for one another, this prohibition would ensure that the regulated 
    engines are used in appropriate applications.
        As noted above, EPA is proposing to require that the original 
    emission control engine label is visible once the certified engine is 
    placed in the vehicle or equipment. If the engine label is obscured as 
    a result of the vehicle or equipment manufacturer's placement of the 
    engine in the nonroad vehicle or equipment, the vehicle or equipment 
    manufacturer would be required to attach an identical but supplemental 
    label, in a readily visible location on a part necessary for normal 
    vehicle or equipment operation before it is introduced into United 
    States commerce.
        Section 213 gives EPA the authority to require nonroad equipment 
    manufacturers to use certified nonroad engines. For further discussion, 
    see ``V.F. Nonroad Engine and Vehicle Definitions.''
    13. Certification Procedures--Application Process
        The engine manufacturer would be required to submit an application 
    to EPA requesting a certificate of conformity for each engine family 
    for every model or calendar year. Certificates would be issued to cover 
    production for a single model year. See ``V. W. Duration of 
    Certificates of Conformity, Definition of Model Year, Annual Production 
    Period'' for further discussion of these issues. An application for a 
    certificate would be submitted every model year even when the engine 
    family does not change from the previous certificate, although 
    representative test data could be reused in the succeeding model year's 
    application. If the emissions from the test engine were below the 
    applicable standards and EPA believed that all other requirements of 
    the regulation were met, EPA would issue a certificate of conformity 
    for that engine family.
        The application would need to provide EPA with sufficient 
    information to determine the appropriate test results and emission 
    characteristics of the engine family. It would also allow EPA to 
    determine test engine compliance with the applicable emission standards 
    in a timely manner. It would be important that the engine manufacturer 
    succinctly, fully, and accurately submit all pertinent information to 
    EPA and maintain internal records which could be easily accessed if 
    such access is determined to be necessary by EPA.
        If changes to an engine family configuration occur after the 
    application is submitted which cause the changed version to be the 
    engine family's worst case emitter, then emission testing of the 
    changed version is required. Additionally, the Administrator may 
    require a manufacturer to conduct testing to demonstrate compliance.
        The application would be submitted to the United States 
    Environmental Protection Agency, Certification Division, Office of 
    Mobile Sources, 2565 Plymouth Road, Ann Arbor, MI 48105. A second copy 
    of the application would be forwarded to Manufacturers Operation 
    Division, Office of Mobile Sources, 401 M St., SW (Mail Code 6405J), 
    Washington, DC 20460. The application would include the following 
    information:
         A description of the basic engine design including engine 
    family specifications,
         A complete description and explanation of how the emission 
    control system operates, including a detailed description of all 
    emission control components, and a listing of the engine and emission 
    control calibrations,
         Part numbers for all emission control components which 
    might reasonably be expected to affect emissions,
         Proposed test engine selection and the rationale for such 
    a selection,
         A description of the test engine starting instructions, 
    fuel, and lubricants to be used,
         A description of the operating cycle and the service 
    accumulation period necessary to break in the test engine,
         A description of all adjustable operating parameters,
         Information relating why the physical limits or stops used 
    to establish the physically adjustable range of each parameter were 
    effective,
         A description of the rated speed(s) and power(s) within 
    the engine family,
         Fuel flow rates for each configuration within the engine 
    family,
         The proposed maintenance instructions, the emission 
    warranty, and emission control label,
         All test data obtained by the manufacturer on the test 
    engine,
         A description of the test facilities, test equipment, and 
    test procedures,
         A section which incorporated any revisions or amendments 
    to the application, including any production changes,
         A list of official manufacturer contacts, organizational 
    chart, and individual designated to receive the certificate of 
    conformity,
         The projected annual sales for the engine family,
         A statement indicating which information in the 
    application was confidential, and
         An unconditional statement certifying that all engines in 
    the engine family complied with all the requirements of the Clean Air 
    Act and this regulation.
    14. Certification Procedures--Testing Overview and Preliminaries
        EPA is proposing that the emission level used to certify an engine 
    family be equal to the highest emission test level reported for any 
    engine configuration in that family. The engine manufacturer would be 
    responsible for selecting and testing one engine from each engine 
    family which is most likely to be that engine family's worst case 
    emitter. The criterion for selecting the worst case engine would be 
    that engine configuration which has the highest weighted brake-specific 
    fuel consumption over the appropriate engine test cycle. EPA could 
    verify the test results by requiring Administrator testing of this 
    engine. EPA would also have the option to test any available test 
    engine representing other configurations in the engine family.
        Before emission testing was carried out, the manufacturer would 
    perform service accumulation on each test engine over the dynamometer 
    hour accumulation cycle of its choice based on good engineering 
    practices (for example, a cycle representative of typical ``break-in'' 
    operation of a new production engine in actual use). For each engine 
    family, the manufacturer would determine the number of hours required 
    to stabilize the emissions of the test engine. However, the number of 
    hours which the manufacturer chose could not exceed 12 hours. EPA does 
    not believe a break-in time greater that 12 hours is necessary to 
    stabilize new engine emissions. In addition, this cutoff is necessary 
    to ensure that EPA gets an equitable view of stabilized emissions over 
    all engine families which may vary with respect to HC and CO emission 
    degradation and NOX emission improvement with time. The 
    manufacturer would maintain, and provide in its application to the 
    Administrator, a record of the rationale used both in making the 
    dynamometer cycle selection and in making the service accumulation 
    hours determination.
        The manufacturer would be required to conduct emission tests of 
    selected engine(s) using the proposed test procedure discussed herein. 
    Finally, the proposed rule does provide for Administrator approval of 
    special test procedures if the small SI engine is not capable of being 
    satisfactorily tested under the proposed test procedures.
    15. Certification Procedures--Emission Test Procedure for HC, CO, and 
    NOX
        EPA is proposing a single test procedure with three different test 
    cycles for measuring HC, CO, and NOx. One cycle would be for all 
    Class III, IV, and V engines (Cycle C), while two cycles would be 
    possible for Class I and II engines (Cycles A and B).
        Cycle B would only be used for those Class I and II engine families 
    in which 100 percent of the engines were sold with a governor which 
    maintained engine speed within  two percent of rated speed 
    (rated speed means the speed at which the manufacturer specifies the 
    maximum rated power of an engine) under all operating conditions. Cycle 
    B would be a 6-mode steady state cycle consisting of five power modes 
    at rated speed and one no-load mode at idle speed. For all other Class 
    I and II engines, the test cycle to be used would be Cycle A. Cycle A 
    would be identical to Cycle B, except the five power modes would be run 
    at intermediate engine speed (intermediate speed is defined as 85 
    percent of rated speed).
        For Class III, IV, and V engines, the engine manufacturer would be 
    required to use Cycle C. Cycle C is a 2-mode steady state cycle 
    consisting of one power mode (at rated speed) and one no-load mode at 
    idle speed. The test modes for each cycle would be run in a prescribed 
    order.
        The three test cycles (modes and power settings) documented in the 
    proposed regulations are based on work performed by the Society of 
    Automotive Engineer's (SAE) Small Engine Committee. The SAE Small 
    Engine Committee has published a recommended practice for measuring 
    gaseous exhaust emissions from small utility engines typically less 
    than 20 kW. This recommended procedure is known as SAE J1088. Test 
    Cycles A, B, and C are all taken from J1088. The mode weighting factors 
    are taken from work performed by CARB.
        In addition, the International Standards Organization (ISO) has 
    published recommended test cycles for measuring exhaust emissions from 
    reciprocating internal combustion engines. Recommended exhaust gas 
    measurement procedures and test cycles for reciprocating internal 
    combustion engines are contained in ISO 8178, Part 4. ISO has three 
    test cycles for spark-ignition engines less than 20 kW termed G1, G2, 
    and G3 which are identical to SAE Cycles A, B, and C, respectively.
        EPA believes the proposed test procedures are adequate for the 
    proposed emission standards. The purpose of a certification test 
    procedure is to adequately represent the emission levels produced by 
    the test engine when it is used in actual operation. The test procedure 
    in this proposed rule does this. The 6-mode test cycles (Cycle A and 
    Cycle B) used for Class I and II engines and the 2-mode cycle (Cycle C) 
    used for Class III, IV, and V engines were developed by the Society of 
    Automotive Engineer's Small Engine Committee to cover the broad range 
    of engine operating conditions seen by small engines. The weighting 
    factors were developed by CARB using data supplied by the small engine 
    industry. The weighting factors are intended to be representative of 
    the modes (speed and power conditions) used by the broad range of small 
    gasoline engines. The Agency believes these weighting factors are 
    sufficient for this proposed rule.
        The methods used to measure the gaseous emissions of HC, CO, and 
    NOX for all small engines would be independent of the type of 
    engine and test cycle. EPA proposes to allow manufacturers to sample 
    emissions using either the Raw Gas Method (raw) or the Constant Volume 
    Sampling Method (CVS). Using either method, each test engine would be 
    stabilized at each mode before emission measurement began. After 
    stabilizing the power output during each mode, the concentration of 
    each pollutant, exhaust volume, and fuel flow would be determined. The 
    measured values would be weighted and then used to calculate the grams 
    of exhaust pollutant emitted per kilowatt-hour.
        SAE J1088 contains a recommended procedure for the measurement of 
    gaseous emissions using the Raw Gas Method. A recommended testing 
    procedure, such as SAE J1088 or ISO 8178, by definition allows 
    sufficient flexibility for individual manufacturers to develop unique 
    features in their test procedures while still being within the 
    allowable guidance. This flexibility is not a desirable feature in a 
    regulatory program where both manufacturers and EPA want to ensure 
    uniformity between test labs, since conformity and compliance testing 
    decisions are binding on the parties involved. For this reason, the 
    test procedures proposed by EPA are not identical to SAE J1088 or ISO 
    8178, but are compatible with those procedures.
        EPA understands the importance of compatibility between the EPA 
    proposed test procedures and those used to demonstrate emission 
    compliance for other regulatory agencies within the U.S. and throughout 
    the world. Compatibility allows a manufacturer to exercise the cost 
    efficiencies of using one engine configuration to demonstrate emission 
    compliance in more than one market. EPA has tried to establish a test 
    procedure that is compatible with both CARB's utility engine test 
    procedure and with ISO 8178. As a result, EPA expects that a 
    manufacturer using the resultant EPA procedure would also meet the CARB 
    and ISO requirements. However, since the SAE and ISO procedures are 
    recommended practices and do not have stringent test parameter 
    tolerances, a manufacturer using the SAE or ISO procedure may or may 
    not meet EPA requirements.
    16. Administrator Testing
        EPA is proposing Administrator testing provisions that allow EPA 
    flexibility in determining when and where engine testing may occur. 
    This is necessary given EPA's limited testing facilities.
        Specifically, this provision would allow EPA to require test engine 
    testing at any given location, including at a manufacturer's facility. 
    The Administrator would be empowered to require the manufacturer to 
    make available such instrumentation and equipment that was specified by 
    the Administrator. Any testing conducted at a manufacturer's facility 
    would be scheduled by the manufacturer as promptly as possible. 
    Authorized EPA personnel would be given access to the facilities to 
    observe such testing.
    17. Catalyst Durability
        EPA expects the emission controls used to meet the exhaust emission 
    standards specified in this rulemaking to be durable so that emission 
    reduction benefits are realized not only when the engines are new, but 
    also during operation in-use, over time. Although EPA is not proposing 
    full emission control system durability demonstration requirements in 
    this notice, manufacturers are fully expected to design such systems to 
    be effective under normal in-use operating conditions over time. Full 
    emission control system durability demonstration requirements are 
    expected to be included in the Phase 2 regulations for small SI 
    engines. However, EPA has concerns that certain emission control 
    components, namely catalysts, warrant separate consideration. 
    Therefore, EPA is proposing durability demonstration requirements for 
    catalysts in this notice as discussed in greater detail in ``V. U. 
    Catalyst Durability.''
    18. Information Requirements, Application for Certificate of 
    Conformity, Amendments
        This rule's information retention requirements are similar to those 
    proposed in the nonroad large CI rule. EPA believes that the proposed 
    information requirements are sufficient to adequately determine 
    compliance with this regulation and the appropriateness of awarding a 
    certificate of conformity.
        A manufacturer would be responsible for retaining certain 
    information applicable to each test engine along with copies of the 
    submitted applications for individual certificates of conformity. A 
    manufacturer would also be required to submit an amendment(s) to the 
    application or certificate of conformity whenever additional small SI 
    engines were added to an engine family or changes were made to a 
    product line covered by a certificate of conformity. Notification 
    normally would occur prior to either producing such engines or making 
    such changes to a product line.
    19. Selective Enforcement Auditing Program
        EPA is proposing to conduct a Selective Enforcement Auditing (SEA) 
    program of small SI engines as authorized by section 213 of the CAA. 
    The small engine SEA program would be an emission compliance program 
    for new production small SI engines in which manufacturers would be 
    required to test engines as they leave the assembly line, with EPA 
    oversight. Through SEA testing, EPA could determine with reasonable 
    statistical certainty whether or not tested engine families were in 
    compliance with the Act.
        EPA believes that an SEA program is necessary to verify that 
    production engines comply with applicable regulations. Since 
    certification would be based on preproduction prototype engines which 
    often contain specially built and installed components, production 
    engines could still fail to meet emission standards if quality control 
    was inadequate. SEAs would provide a means to test actual production 
    engines as they came off the assembly line. Since no in-use enforcement 
    program is being proposed for small SI engines, SEA provides the only 
    opportunity for EPA to determine the compliance of production engines.
        EPA would assign a limit to the number of SEAs each manufacturer 
    could receive during a model year. As in the on-highway SEA program, 
    this annual limit would be used to provide assurance to manufacturers 
    that EPA would not significantly overburden a manufacturer with an 
    unreasonable number of audits during the model year.
        Each SEA would be an audit of one engine family, and each passing 
    audit would count toward the manufacturer's annual limit. EPA is 
    proposing an annual limit of two for each manufacturer with projected 
    annual production of less than 100,000 engines. For manufacturers with 
    annual production of 100,000 or more engines the annual limit would be 
    the greater of either two or the number determined by dividing the 
    number of engine families certified in that model year by five, and 
    rounding to the nearest whole number. For example, a manufacturer with 
    a projected annual United States production of 600,000 engines with 13 
    certified engine families would have an annual limit of three, and a 
    manufacturer with a projected annual production of 300,000 small SI 
    engines and 22 engine families would have an annual limit of four.
        EPA believes this method of determining annual limits is most 
    appropriate for the small SI engine industry. EPA is proposing the 
    minimum annual limit of two because manufacturers may change production 
    during the model year. If a manufacturer passed an SEA early in a model 
    year, the manufacturer might subsequently implement changes in its 
    production process which could increase engine emissions. With an 
    annual limit of two, EPA would have the flexibility to audit a 
    manufacturer early in the model year, and then return later in the 
    model year if that manufacturer implemented a change in production 
    which could increase engine emissions.
        As described above, EPA is also proposing that manufacturers with 
    projected annual production of 100,000 small SI engines or more may 
    have an annual limit of more than two. EPA believes it might be 
    necessary to conduct more than two SEAs on larger engine manufacturers 
    when they have a large variety of engine families. When manufacturers 
    have a variety of engine families, an SEA might only check a small 
    portion of the manufacturers' production. Therefore, by dividing the 
    number of engine families certified by larger manufacturers by five, 
    EPA could establish a higher annual limit for those manufacturers with 
    a variety of engine families with different emission characteristics. 
    Manufacturers with lower production should be assured that EPA would 
    not overburden its limited test facilities with SEAs.
        Annual limits would act as a cap and would not necessarily be the 
    actual number of audits a manufacturer received. EPA would not exceed a 
    manufacturer's annual limit unless the Agency had reason to believe 
    noncompliance was occurring. EPA requests comment on the proposed 
    method for determining annual limits. The SEA program strives to 
    encourage manufacturers to perform self-auditing and promptly remedy 
    the emission noncompliance it discovers. Therefore, EPA would consider 
    reducing the number of audits conducted by the Agency, minimizing 
    audits of engine families which are unusually burdensome to audit, or 
    both options, if the manufacturer provided substantial data to 
    demonstrate conformity of actual production engines with the applicable 
    emission standards. EPA suggests that manufacturers unfamiliar with 
    self-auditing review existing on-highway programs, such as CARB's 
    Quality Audit Program or the manufacturers' Assembly Line Test Data, 
    for guidance in implementing an in-house auditing program. Examples of 
    audit programs are available in the docket for this rulemaking.
        EPA would review self-audit data and procedures used in acquiring 
    the data to assess the validity and representativeness of each 
    manufacturer's self-audit program. The primary criteria EPA would use 
    in evaluating the in-house programs are sample size, randomness within 
    the family of the audited engine(s), frequency of testing, and the 
    applicable required test procedures. EPA would discount the value of 
    any self-audit data if the Agency received indications of noncompliance 
    or concluded that the data were invalid, incomplete, unrepresentative, 
    or insufficient. In addition, manufacturers with a comprehensive self-
    audit program would be subject to spot checks with EPA oversight to 
    provide EPA assurance of compliance. EPA requests comment on this 
    issue.
        Manufacturers would be notified of an SEA by means of a test order. 
    This test order would specify the engine family to be audited. EPA 
    might also specify an engine configuration or range of configurations 
    from a family to be audited. However, EPA would reserve the option to 
    select all configurations within an engine family for an SEA. To 
    minimize the burden on manufacturers, EPA would consider requests by 
    manufacturers to exclude particular engines or engine configurations 
    from a test sample. Justification for such requests could be to avoid a 
    delay in shipment of urgent customer-ordered engines or to minimize 
    test cell set-up time by selecting engines of similar physical 
    configurations.
        Test orders would include information relevant to the SEA. The test 
    order would indicate any specific procedures, such as the time to begin 
    selecting engines, during the course of the audit. Additionally, the 
    test order would authorize EPA enforcement officers, upon presentation 
    of enforcement credentials, to inspect engine production, test 
    facilities, storage facilities, and records necessary to establish 
    compliance with nonroad regulations.
        Due to differences between the small SI industry and the on-highway 
    industry, EPA is proposing that some aspects of the on-highway SEA 
    program be modified for small SI engines. Historically, on-highway 
    engine SEAs have been conducted on engine configurations: a specific 
    engine family, an engine code, a rated speed and an emission control 
    system. EPA believes that making an entire small engine family subject 
    to an audit would lead manufacturers to use extra care when grouping 
    engines in a family. Consequently, EPA is proposing that nonroad SEAs 
    be conducted by sampling engines from within an engine family. EPA 
    requests comments on this aspect of the program.
        SEA engines would typically be selected from a point of final 
    engine assembly or from a storage or shipping facility. Most often, 
    this selection point would be at the end of the engine assembly line, 
    where no further quality control procedures happen or parts would be 
    installed on the engines. Selection of imported engines could occur at 
    a port of entry. SEA engines could not receive any additional 
    inspections or quality control other than that of normal production 
    engines and pre-test safety checks. Engines would be tested in the same 
    order as they were selected. EPA requests comment on the feasibility of 
    selecting equipment, then removing the engine for audit testing.
        EPA proposes to include ports of entry or storage locations in the 
    United States as locations for EPA selection of foreign- produced small 
    SI engines for SEA emission testing at laboratories in the United 
    States. The location of these selections could be designated by the 
    manufacturer to minimize disruption and shipping costs. The 
    manufacturer would be responsible for ensuring that a test facility in 
    the United States was available for SEA testing.
        ``Port selection'' would assist the Agency in reducing its travel 
    costs. Recently, in the on-highway program, EPA has had requests from 
    light-duty vehicle manufacturers to conduct port selection during SEAs. 
    These audits were performed and ran smoothly. EPA might permit 
    reasonable maintenance and inspections of port-selected engines to 
    address problems that could result from long-term storage, ocean 
    shipping, or repeated handling. EPA requests comments on the port 
    selection aspect of the SEA program.
        Prior to testing SEA engines, manufacturers could operate engines 
    to break in engine components. This break-in or service accumulation of 
    an SEA engine family would follow the same procedures and could be up 
    to 12 hours or the same number of break-in hours accumulated for that 
    family's emission data engine during certification. Service 
    accumulation would be performed expeditiously and in a manner using 
    good engineering judgment.
        Audit engines would be tested using the same test cycle, either 
    Test Cycle A, B, or C, as was used in certification; however, 
    deviations allowed in certification from the full test procedures as 
    described in proposed 40 CFR part 90 would not be permitted in SEAs.
        EPA is proposing that small SI engines will be selected for SEA 
    testing at a rate of at least four engines per day, unless production 
    is less than four engines per day. To minimize delays in shipment of 
    engines to customers, manufacturers could test the first engines 
    selected for an audit while additional engines were produced.
        The total number of engines tested in an SEA would be dictated by 
    the number of engines required to reach the statistically acceptable 
    pass/fail decision within the sampling plan applied. EPA is proposing a 
    sequential sampling plan for small SI engine SEAs. These sampling plans 
    have been designed to meet a 40 percent Acceptable Quality Level (AQL) 
    and to ensure low statistical risks of incorrect pass/fail 
    determinations. The maximum theoretical percentage of failing engines 
    for passing an SEA is 40 percent. EPA is proposing a 40 percent AQL for 
    the small SI engine SEA program. EPA has used this AQL since the 1970s 
    for the on-highway program, and EPA currently has no reason to propose 
    a different AQL for a nonroad program. EPA is proposing that the small 
    SI engine SEA program use the same sampling plans used for the on-
    highway heavy-duty engine SEA program.
        EPA proposes that engine manufacturers with projected United States 
    annual sales of 7,500 or greater must complete a minimum of two engine 
    tests per day during an SEA. Engine manufacturers with projected United 
    States annual sales of less than 7,500 would be required to complete a 
    minimum of one engine test per day during an SEA. A valid emission test 
    or a voided test would each count as one test toward meeting the 
    requirement. EPA requests comments on this aspect of the proposal.
        A test engine's pass or fail determination would be made by 
    comparing final test results to the applicable federal emission 
    standard. Within five working days of the conclusion of an audit, 
    manufacturers would be required to submit a report to EPA summarizing 
    engine test results, test procedures, and audit events such as the 
    date, time, and location of each test, repairs to engines, and the 
    reason for the repair.
        Failure of an SEA could result in suspension or revocation of the 
    certificate of conformity for that family. To have the certificate 
    reinstated subsequent to a suspension, or reissued subsequent to a 
    revocation, the manufacturer would be required to demonstrate, by 
    showing passing data, that improvements, modifications, or replacement 
    had brought the family into compliance. The proposed regulations 
    include hearing provisions which allow the manufacturer to challenge 
    EPA's suspension or revocation decision based on application of the 
    sampling plans or the manner in which tests were conducted.
    20. Importation of Nonconforming Small SI Engines
        EPA is proposing certain restrictions on the importation of 
    nonconforming small SI engines. Such restrictions are based in part on 
    the existing regulations for the importation of nonconforming motor 
    vehicles and motor vehicle engines.
        While EPA provides for an Independent Commercial Importer (ICI) 
    program for motor vehicles and motor vehicle engines, EPA is not 
    certain that an ICI program is necessary or practical for small SI 
    engines. For the on-highway program, ICIs are responsible for all 
    aspects of compliance required of manufacturers (e.g., certification, 
    testing, labeling, warranty, recall, maintaining records). EPA solicits 
    comment on the need for an ICI program for small SI engines. Due to the 
    uncertainty about the need for an ICI program, EPA is proposing in the 
    alternative both to have an ICI program that parallels that of the on-
    highway program, and to have no ICI program in the final rule. EPA 
    currently favors no ICI program for small SI engines; if the Agency 
    determines not to promulgate an ICI program, the proposed regulatory 
    language will be deleted from the final rule.
        This proposal includes a special provision for individuals to 
    import a limited number of nonconforming small SI engines for personal 
    use. EPA expects that individuals may not know of the regulations 
    applicable to small SI engines and, without this once in a lifetime 
    exemption, individuals may be stopped at a port of entry with small SI 
    engines and equipment included with their personal possessions. 
    Additionally, this exemption would relieve a significant burden on EPA 
    and the U.S. Customs Service. EPA is proposing that, at least for Phase 
    1 of these regulations, individuals be permitted to import up to three 
    nonconforming small SI engines and not have these engines brought into 
    compliance with the proposed standards. This is a one-time exemption 
    (for one importation) in which individuals are permitted to import 
    these engines for personal use and not for purposes of resale. This 
    exemption would not require prior EPA written approval. Additional 
    small SI engines, after an individual's limit of three, would not be 
    permitted to be imported under the proposal unless otherwise provided 
    under another exemption or exclusion. All small SI engines imported for 
    purposes of resale would be required to be imported and modified by an 
    ICI. If EPA does not finalize an ICI program, such engines may not be 
    imported for resale. EPA requests comment on this proposed exemption.
        Today's proposal also provides certain exemptions to the 
    restrictions on importing nonconforming small SI engines. These include 
    exemptions for repairs and alterations, testing, precertification, 
    display, national security, hardship, small SI engines greater than 20 
    original production years old, and certain small SI engines proven to 
    be identical, in all material respects, to their corresponding United 
    States certified versions. These exemptions would also include the 
    exclusion of nonconforming engines used solely in competition.
        EPA is not proposing to include provisions for a catalyst control 
    program for small SI engines. The catalyst control program for motor 
    vehicles consists of a special provision for catalyst-equipped vehicles 
    to be operated in countries where the catalyst may be poisoned by the 
    use of leaded fuel. In the on-highway catalyst control program, owners 
    may either have the catalyst removed while the vehicle is operated 
    outside of the United States or, if the vehicle is driven only in 
    countries that have a wide availability of unleaded gasoline, 
    demonstrate by using a plumbtesmo test that the vehicle was not 
    operated on leaded fuel. EPA is not proposing a catalyst control 
    program for small SI engines because EPA does not expect that U.S. 
    certified small SI engines equipped with catalysts will be used in 
    countries that do not have a wide availability of unleaded fuel and 
    then imported into the United States. Additionally, EPA has no 
    knowledge of the extent to which catalysts will be used on Phase 1 
    small SI engines. EPA requests comments on the absence of a catalyst 
    control program and the need for such a program for Phase 1 engines.
        Finally, EPA is not proposing to include a provision for small SI 
    engine Designated Canadian Importer (DCI). EPA's motor vehicle import 
    program has a special provision in which DCIs may import and sell 
    Canadian vehicles that were manufactured to be identical in all 
    material respects to U.S. certified counterparts. Because EPA has no 
    indication that Canada will adopt EPA's Phase 1 small SI engine 
    standards, engines imported from Canada into the United States will 
    likely be nonconforming engines and thus would not be eligible to be 
    imported by a small SI engine DCI. Consequently, EPA expects that 
    provisions for small SI engine DCI are unnecessary. EPA requests 
    comment on the absence of a DCI program and the need for such a program 
    for Phase 1 engines.
        Importation regulations are joint regulations between EPA and the 
    United States Department of the Treasury (Customs Service). The 
    citation for United States Customs Service, Department of Treasury 
    regulations governing import requirements is reserved. The citation 
    will be inserted upon promulgation by the United States Customs Service 
    of the applicable regulations.
    21. Defect Reporting and Voluntary Recall
        EPA is proposing that a manufacturer of small SI engines file a 
    defect information report whenever a manufacturer identifies the 
    existence of a specific emission-related defect in 25 or more engines 
    in a single engine family manufactured in the same model year. However, 
    no report would need to be filed if the defect was corrected prior to 
    the sale of the affected engines to the ultimate purchaser. These 
    proposed reporting requirements are similar to the requirements found 
    in the on-highway program. EPA is currently revising the on-highway 
    reporting program and new regulations will shortly be proposed. The new 
    regulations may encompass both on-highway and the nonroad sector.
        EPA is also proposing that individual manufacturers establish, when 
    appropriate, voluntary recall programs. EPA is proposing limited 
    guidelines which engine manufacturers would follow when undertaking 
    such a program. EPA invites comments on how such a voluntary program 
    might be effectively structured.
    22. Emission Defect Warranty Requirements
        EPA is proposing that engine manufacturers provide an emission 
    warranty for the first two years of engine use. The two-year warranty 
    period was adopted from California's lawn and garden regulations to 
    reduce the burden on manufacturers of administering two different 
    warranty programs.
        EPA is also considering ``hours of engine use'' as an alternative 
    measure for the warranty period. Under this option, an engine 
    manufacturer would need to install some form of metering device to 
    track the hours of use for an engine. EPA solicits comments on this 
    metering option, the feasibility of outfitting small engines with such 
    devices, and the feasibility of employing the useful life hours 
    generated in the Nonroad Study as a measure for an hours-based warranty 
    period.
        EPA believes that a warranty program is necessary to ensure the 
    quality of emission control components and systems that are used on or 
    in nonroad engines and also to protect consumers from costly repairs 
    that result from manufacturing defects. Furthermore, a warranty program 
    gives the engine owner/operator the incentive to get emission-related 
    system failures repaired, since failures to the emission control system 
    do not always affect the ability of an engine to work.
        The warranty requirements proposed today are consistent with 
    emission defect warranty policies developed for on-highway vehicles, 
    located in section 207(a) of the Act. Manufacturers of new nonroad 
    engines would warrant to the ultimate purchaser and each subsequent 
    purchaser that such engine was (1) designed, built, and equipped so as 
    to conform at the time of sale with applicable regulations under 
    section 213 of the Act, and (2) free from defects in materials and 
    workmanship which cause such engine to fail to conform with applicable 
    regulations for its warranty period. The related parts and components 
    covered by section 207(a) are detailed in an advisory parts list issued 
    by EPA on July 15, 1991, and encompass parts and systems which are or 
    may be used on small SI engines. A copy of the parts list is in the 
    public docket for this rulemaking. EPA invites comments on this parts 
    list and its applicability to small SI engines.
        EPA is currently developing more detailed regulations that will 
    further clarify manufacturers' responsibilities under section 207(a) 
    for both on-highway and nonroad engines. EPA will rely on the existing 
    207(a) practices until those regulations are finalized.
    23. Tampering Enforcement
        Today's action would make it illegal for any person to tamper with 
    any emission-related component or system installed on or in a small SI 
    engine. EPA believes that an engine would more likely continue to meet 
    the applicable emissions standards in-use if the engine maintained its 
    certified configuration. Therefore, EPA believes it is necessary to 
    impose antitampering provisions for such engines and is proposing that 
    the existing policies developed for on-highway tampering also apply to 
    engines included in this rule. See Office of Enforcement and General 
    Counsel; Mobile Source Enforcement Memorandum No. 1A, June 25, 1974. A 
    copy of this memorandum is in the public docket for this rulemaking.
    
    V. Discussion of Issues
    
        This section contains further discussion of a number of issues 
    raised during the development of this proposal.
    
    A. Use of Metric Units
    
        Metric units are used throughout the proposed rule without English 
    equivalents. This is done in compliance with the Metric Conversion Act 
    of 1975, as amended, and Executive Order 12770, July 25, 1981, which 
    directs all federal agencies to use metric as the primary unit in 
    regulations by September 30, 1992 and to only provide English 
    equivalents when the affected party(s) uses English as the primary 
    unit.
        EPA acknowledges slight differences between the two systems and the 
    use of mixed units by CARB. Comments are solicited on the impact of 
    using only metric units or the need for including the English 
    equivalent.
    
    B. Use of Power Rating as Cutoff for Applicability
    
        EPA is proposing to limit the applicability of this action to 
    engines at or below 19 kW (25 horsepower) rated power as compared to 
    CARB's 25 horsepower limit. EPA considered limiting the regulation's 
    applicability based instead on a total displacement, but has chosen to 
    propose a power-based cutoff for consistency with CARB.
        EPA is aware that the measurement of rated power is subject to 
    engine configuration and test conditions, and that a cutoff based on 
    power might create an incentive for manufacturers with engines just 
    below the cutoff to change engine and/or test procedure parameters to 
    result in a higher measured power.
        In examining data from Power Systems Research (PSR),\4\ EPA has 
    identified a relationship between total displacement and rated power 
    which suggests that a one-liter total displacement cutoff would affect 
    nearly an identical group of engines as a 19 kW cutoff. However, using 
    such a cutoff would cause a limited number of engines to be included 
    that would not be included using a 19 kW cutoff (that is, engines above 
    19 kW but less than one liter displacement). Examples include larger 
    two-stroke engines. A limited number of engines would also go 
    unregulated under this scenario (that is, engines under 19 kW but 
    greater than one liter). Examples include larger industrial four-stroke 
    engines.
    ---------------------------------------------------------------------------
    
        \4\Power Systems Research (PSR), Engindata North America and 
    Parts Link Aftermarket, 1992, St. Paul-Minneapolis, Minnesota.
    ---------------------------------------------------------------------------
    
        Because of the differences in applicability between a power- and 
    displacement-based cutoff, EPA has chosen to propose the former despite 
    the potential advantages of the latter. EPA requests comment on the 
    appropriateness of instead limiting this regulation to engines under 
    one-liter total displacement (or a different displacement limit), or 
    limiting the applicability to engines that are below displacement or 
    power cutoffs. Comments should address the relative market and 
    environmental impact of the alternative approaches, as well as the 
    relative enforceability.
    
    C. Exclusion of Compression-ignition Engines
    
        EPA is not proposing to regulate small CI engines in this action. 
    As part of the Sierra Club v. Browner settlement, EPA will determine by 
    November 1996 whether to undertake a rulemaking which targets emissions 
    from small CI engines. CI engines have different emission 
    characteristics from the engines addressed by this proposal, emitting 
    much lower levels of HC and considerably higher levels of NOx than 
    small SI engines.
        In contrast to the current proposal, which is focused on achieving 
    reductions in emissions of HC, a regulation addressing CI engines would 
    likely focus on NOx. EPA lacks sufficient data regarding baseline 
    emissions and control technologies for nonroad CI engines in this power 
    range to determine appropriate standards at this time. Therefore EPA 
    has chosen to exclude these engines from the current proposal, which is 
    aimed at achieving significant reductions in small engine HC emissions 
    on an expedited basis.
        EPA is raising this as an issue because of the potential that 
    unregulated CI engines could be substituted for post-control SI 
    engines. In EPA's view, while this may occur in some cases (for 
    example, small agricultural tractors), the most price-sensitive 
    products such as string trimmers and lawnmowers are unlikely to shift 
    significantly toward CI engines due to technological limitations, 
    consumer preference, or both.
        The Agency solicits comment on the exclusion of compression-
    ignition engines, and on the appropriate test procedure and standards 
    that should be applied to CI engines if they were to instead be covered 
    by this regulation.
    
    D. Exclusion of Recreational Propulsion Engines
    
        EPA is proposing to exclude engines used in recreational vehicles, 
    examples of which include snowmobiles, off-road motorcycles, and all-
    terrain vehicles. Golf carts do not qualify as recreational vehicles 
    under this proposal, and they would be subject to the emission 
    standards of this rule. Engines used in such recreational vehicles are 
    defined by the following characteristics: Use of a continuously 
    variable throttle (as opposed to a governor), rated engine speeds in 
    excess of 5,000 RPM, and wide variations in both engine load and speed.
        EPA's primary reason for this exclusion is the extremely transient 
    operation of the products in which these engines are used, which limits 
    the ability of the proposed steady state test procedure to adequately 
    represent exhaust emissions. This exclusion is not based on a 
    determination that these engines do not contribute to air pollution and 
    therefore need not be controlled. EPA has chosen to exclude engines 
    used in recreational vehicles in order that it may proceed quickly with 
    a program for other small SI engines. As part of the Sierra Club v. 
    Browner settlement, EPA will determine by November 1996 whether to 
    undertake a rulemaking which targets emissions from engines used in 
    recreational vehicles.
        EPA solicits comment on the exclusion of engines used in 
    recreational vehicles, on the criteria used to identify such engines, 
    and on the appropriate test procedure and emission standards if EPA 
    were to include such engines in this proposal.
    
    E. Exclusion of Marine Propulsion Engines
    
        EPA proposes to exclude marine propulsion engines, examples of 
    which, in this power range, include outboard marine engines. EPA is 
    developing emission standards for marine propulsion engines in a 
    separate action. However, small SI engines used on marine vessels for 
    purposes other than propulsion, such as generators and pumps, are not 
    excluded in this proposal.
    
    F. Nonroad Engine and Vehicle Definitions
    
        EPA is proposing to incorporate in this rule the nonroad engine 
    definition proposed in the large CI rule. EPA will include in this rule 
    any changes to that definition included in the final large CI rule. EPA 
    is also proposing to amend the definition of nonroad vehicle proposed 
    there by adding the following sentence: ``Nonroad vehicle also includes 
    equipment that is powered by nonroad engines.''
        The statutory definition of nonroad vehicle adopted by Congress in 
    the 1990 CAA Amendments provides little guidance as to what is a 
    nonroad vehicle. Rather, statutory language describes only what is not 
    a nonroad vehicle, namely, motor vehicles and vehicles used solely for 
    competition. A review of the Conference Report, the Statement of Senate 
    Managers, and the Statement of House Managers does not provide any 
    additional guidance. It is necessary to examine both the House and 
    Senate Committee Reports of the original legislation before this issue 
    is discussed.
        The United States House of Representatives, Committee on Energy and 
    Commerce, Report on H.R. 3030, offers some insight into the meaning of 
    both nonroad engine and vehicle. In part the report states, ``(T)he 
    term `nonroad engine' is defined for purposes of this section to 
    include certain internal combustion engines not used in a motor vehicle 
    or a competition vehicle, while a nonroad vehicle is a vehicle powered 
    by (a) nonroad engine that is not a motor vehicle and not used solely 
    for competition. Stationary internal combustion engines are to be 
    regulated under Title I of the Clean Air Act amendments of 1990, and 
    are not subject to the requirements of this section.''\5\
    ---------------------------------------------------------------------------
    
        \5\H. Rep., Legislative History of the 1990 Amendments to the 
    Clean Air Act of 1990, Committee on Energy and Commerce to accompany 
    H.R. 3030, May 17, 1990, at 310.
    ---------------------------------------------------------------------------
    
        Equally enlightening is the report of S. 1630 from the United 
    States Senate, Committee of Environment and Public Works, which 
    discusses at some length the Committee's understanding of what the 
    terms nonroad engine and nonroad vehicle mean. A pertinent part of the 
    report states,
    
    * * * ``non-road engines'' include a wide range of engine uses and 
    vehicles. The term includes, for example, diesel locomotives, farm 
    and construction equipment, utility engines such as lawn and garden 
    equipment, marine vessels, forklifts and airport vehicles. The 
    definition in the bill for non-road vehicles is an inclusive one 
    that covers all engines that are not used in motor vehicles, or in a 
    vehicle used solely for competition in vehicle racing, that are not 
    regulated by standards promulgated under section 111 of the Act, and 
    that are not subject to regulation under part B of title I of the 
    Act, related to aircraft.\6\
    ---------------------------------------------------------------------------
    
        \6\S. Rep. Legislative History of the 1990 Amendments to the 
    Clean Air Act, Committee on Environment and Public Works to 
    accompany S. 1630, December 20, 1989, at 104-105.
    ---------------------------------------------------------------------------
    
        EPA believes that Congress used the terms ``non-road engine,'' 
    ``equipment,'' and ``vehicle'' interchangeably. It is EPA's belief that 
    Congress intended nonroad vehicles and nonroad engines to be inclusive 
    terms covering all manner of equipment not defined as motor vehicles, 
    vehicles for competition, and stationary sources. Furthermore, there is 
    a practical interrelationship between an engine and the equipment that 
    houses it or is powered by it. Equipment or vehicle characteristics may 
    have a significant impact on the emissions associated with the 
    operation of the engine. The nonroad engine definition proposed in the 
    large CI rule and incorporated in this rulemaking relies to a great 
    extent on this interrelationship between an engine and a piece of 
    equipment to determine whether an engine is a nonroad engine. In future 
    development of a small SI engine program, it may become necessary and 
    appropriate to regulate aspects of equipment to control fuel spillage, 
    evaporative emissions, or refueling emissions. EPA believes that CAA 
    section 213 provides authority for such regulation.
    
    G. Definition of Handheld Equipment
    
        EPA is proposing that engines intended for use in equipment defined 
    as handheld be certified to standards much less stringent than those 
    applicable to engines used in nonhandheld equipment. However, on a 
    percentage basis, the reductions obtained from handheld and nonhandheld 
    engines will be of similar magnitude. Because of the unique 
    characteristics of handheld 2-stroke engines, it is not feasible, given 
    the timing of this proposal and the unique performance requirements of 
    handheld equipment, to require that all engines covered in this 
    proposal meet emission levels that can be achieved by 4-stroke engines 
    used in nonhandheld equipment.
        This distinction is based, in part, on the substantial difference 
    between emissions from current 4-stroke and 2-stroke engines, which is 
    an inherent result of the design differences of these engines. Because 
    of scavenging losses, current 2-stroke engines generally emit 
    approximately ten times more unburned HC (on an energy-specific basis) 
    than their 4-stroke counterparts.
        However, current 2-stroke engines are generally lighter than 
    current 4-stroke engines of the same rated power and can be operated in 
    any orientation. As a result, applications requiring that the operator 
    pick up and/or carry the device while using it (for example, chain 
    saws), are nearly exclusively powered by 2- stroke engines. On the 
    other hand, nonhandheld applications such as lawnmowers, which are 
    currently sold in both 2-stroke and 4-stroke versions, can clearly be 
    powered by 4-stroke engines. Approximately 90 percent of the lawnmowers 
    sold in the United States are powered by 4-stroke engines. Section VII 
    discusses the present market mix of small engines.
        EPA is proposing to distinguish between ``handheld'' and 
    ``nonhandheld'' equipment in a manner that is similar to that adopted 
    by CARB. However, EPA proposes to clarify and expand on California's 
    handheld definition.
        First, in cases where the operator carries all of the equipment's 
    weight during engine operation, the equipment would be classified as 
    handheld. Second, where the equipment is clearly required to operate in 
    any position the equipment would also be classified as handheld. 
    California's handheld definition requires that the equipment must both 
    be carried and used multipositionally in order to qualify for handheld 
    status. EPA requests comment on whether this approach may preclude 
    equipment which is in practice ``handheld'' from qualifying for 
    handheld status. The proposed federal definition does not require that 
    both stated criteria be present for a given piece of equipment to 
    qualify as handheld. One criterion is sufficient. It is EPA's intent 
    that the preceding two criteria allow leafblowers, trimmers (both 
    string and hedge), cutters, or chain saws to qualify for handheld 
    status.
        In addition, EPA is proposing that engines be allowed to meet Class 
    III, IV, or V standards if the dry weight of the equipment they are 
    used in, including engine weight, is under 14 kg, there are no more 
    than two wheels present on the equipment, and at least one of the 
    following three attributes is also present: (1) The operator 
    alternately provides support or carries the equipment throughout its 
    performance; (2) the operator provides support and attitudinal control 
    for the equipment throughout its performance; (3) the engine is used 
    exclusively in a generator or pump.
        EPA believes that a weight-based criterion is an appropriate 
    initial determinant of whether a 2-stroke engine can be handheld. 
    Industry data show clear weight distinctions between those engines 
    which are ``lightweight'' and made for handheld operations and those 
    which are not. For example, review of industry brochures revealed that 
    2-stroke engines were almost always found in equipment under 14 kg. In 
    addition, the presence of not more than two wheels in a given piece of 
    equipment is another important indicator of the need for an operator to 
    either support, carry, or provide attitudinal control for the 
    equipment.
        The first attribute seeks to classify as ``handheld'' equipment 
    which is either carried or supported by the operator throughout the 
    entire engine operation. An operator carries equipment when the full 
    weight of the equipment is borne by the operator. Support means that 
    the operator holds the equipment in position so as to prevent it from 
    falling, slipping, or sinking. The entire weight of the equipment is 
    not necessarily borne by the operator. Legitimate sources of support 
    might include the ground, ice, wood, or concrete. EPA intends that 
    lightweight snowblowers, edgers, and augers qualify for handheld status 
    under this first attribute.
        The second attribute classifies as ``handheld'' equipment which 
    requires either operator support or attitudinal control during the 
    entire operation. Attitudinal control means the operator regulates 
    either the horizontal or vertical position of the equipment. This 
    definition is meant to allow certain lightweight tillers, augers, or 
    edgers to qualify for handheld status. Both ice and earth augers must 
    be carried to each drill site by the operator, and must be supported by 
    the operator during operation. In addition, the operator must control 
    the vertical attitude of the equipment during operation including 
    pulling upward after each hole is drilled. Tillers without wheels or 
    with no more than two wheels are designed to be supported or picked up 
    frequently during operation while maneuvering between rows in a garden. 
    Likewise, the vertical and horizontal position of the tiller is 
    controlled by the operator.
        Finally, the third attribute acknowledges that engines used in 
    lightweight pumps and generators should be allowed to meet the handheld 
    emission standards. Like augers, lightweight generators and pumps are 
    carried to the work site by the operator and may operate at significant 
    distances from electrical-power outlets.
        All other equipment would be classified as nonhandheld equipment. 
    Examples of nonhandheld equipment include lawnmowers, compressors, lawn 
    tractors, garden tractors, tillers with wheels, chippers/grinders, and 
    log splitters.
        EPA believes that the proposed handheld definition identifies 
    sufficient criteria by which all handheld equipment types may be 
    classified. However, it may still be possible that certain equipment 
    types which are in practice handheld applications would not meet this 
    definition. EPA is considering whether to institute a ``case-by-case 
    review process'' so that, where appropriate in the Administrator's 
    judgment, engines used in specific types of nonhandheld equipment would 
    either be reclassified as handheld or would be allowed to meet the 
    handheld emission standards as if that type of equipment was classified 
    as handheld. In such cases, the Administrator might consider factors 
    including, but not necessarily limited to the following: Equipment 
    function and design (for example, handle placement); equipment 
    capability; equipment weight; engine weight; rated power; 
    multipositional operating requirements; presence and number of wheels; 
    presence of other weight supports; availability of similar 4-stroke, 
    electric, and/or nonpowered models by the same manufacturer or 
    competitors; typical operating profiles (including season of use), and 
    nationwide annual industry-wide sales. The manufacturer requesting such 
    a review might be required to demonstrate, based on these and any other 
    pertinent factors, that a 2-stroke engine clearly was a necessary 
    design feature of the equipment concerned.
        EPA is currently aware of at least one type of equipment that, in 
    EPA's view, might need to be evaluated through such a process. Unlike 
    CARB, EPA is not allowing all currently produced 2-stroke snowthrowers 
    to meet standards applicable to engines used in handheld equipment. In 
    approving its regulations, California accepted arguments that 
    nonhandheld 2-stroke snowthrowers should be allowed an exemption from 
    the nonhandheld standards to meet emission standards for handheld 
    engines. In EPA's view, at least two factors could have formed a basis 
    for this decision: First, snowthrowers are operated in the winter, 
    which means that they do not significantly impact ozone nonattainment 
    and thus need not be subject to stringent control aimed at improving 
    ambient air quality; and second, at least some of the lightweight 2-
    stroke snowthrowers that were exempted from nonhandheld standards 
    appear to be designed to be picked up while in operation (for example, 
    to clear porch steps), implying that the use of a 4-stroke engine would 
    significantly limit critical performance features.
        While the first of these factors raises questions regarding the 
    need to control emissions at all from products that are clearly only 
    used in the winter, regardless of their classification as handheld or 
    nonhandheld, those questions must also be weighed against the need to 
    address CO emissions, and the need to protect the health of equipment 
    operators. The second factor reveals potential problems with CARB's 
    definition of ``handheld.'' Specifically, CARB's action with regard to 
    snowthrowers raises questions regarding other ``fringe'' products.
        EPA believes that it would be appropriate to classify as handheld 
    equipment lightweight snowthrowers under 14 kg which have no more than 
    two wheels and which would either be carried or supported during 
    operation. All other snowthrowers would be classified as nonhandheld 
    and required to meet the standards that were generally applicable to 
    engines used in nonhandheld equipment. EPA solicits comment on this 
    proposal.
        Under EPA's proposed definitions, lawnmowers will be classified as 
    nonhandheld equipment and thus engines used in lawnmowers must meet the 
    more stringent nonhandheld emission standards. Manufacturers of 2-
    stroke lawnmower engines have raised concerns over their economic 
    survival if required to meet nonhandheld standards, based on their 
    doubt that cost-effective technology now exists to bring their 2-stroke 
    engines into timely compliance. EPA requests comment on the ability of 
    2-stroke lawnmower engine manufacturers to meet the nonhandheld 
    standards, the impact such a requirement would have on such 
    manufacturers, the need for relief for such manufacturers, and the 
    impact such relief might have on the environmental benefits of this 
    proposal.
        EPA further requests comment on the following options for providing 
    relief to 2-stroke lawnmower engine manufacturers: (1) Provide an 
    extended effective date, such as 1998, for 2-stroke lawnmower engines 
    to meet the nonhandheld standards; (2) allow 2- stroke lawnmower 
    engines to meet the handheld engine standards until the effective date 
    of the second phase of small SI engine regulations; (3) cap the number 
    of 2-stroke lawnmowers allowed to certify to the handheld standards to 
    the number sold in the year this proposal is published or promulgated 
    until the effective date of the second phase of small SI engine 
    regulations; or (4) allow a declining percentage of 2-stroke lawnmower 
    engines to meet the handheld standards, such as 100 percent in 1996, 75 
    percent in 1997, 50 percent in 1998, and 25 percent in 1999, so that by 
    the year 2000, all 2-stroke lawnmower engines sold would meet the 
    nonhandheld emission standards.
        EPA solicits comment on the proposed definition of handheld 
    equipment and on the potential process for handling those types of 
    equipment that may pose difficulties to classification. EPA also 
    requests comment on the specific cases discussed. Finally, EPA solicits 
    comment on alternative definitions that may be appropriate. Alternative 
    definitions of ``handheld equipment'' might include, but need not be 
    limited to, the following elements:
         Lack of wheels or other means of support (other than 
    operator), I11 Overall weight below some limit such as 10 kg or 
    20 kg, and
         Portion of overall weight attributable to current engine 
    above some minimum, such as 75 percent.
    Conversely, alternative definitions of ``nonhandheld equipment'' could 
    include elements such as:
         Presence of wheels or other means of support other than 
    operator,
         Overall weight above some minimum such as 10 kg or 20 kg, 
    and
         Portion of overall weight attributable to current engine 
    below some limit such as 75 percent.
        It should be recognized that recent engineering developments may 
    eventually obviate the need to provide different standards for handheld 
    and nonhandheld equipment engines. Future technical solutions may 
    provide engines used in all applications with comparable emission 
    performance capability. For example, one firm has recently announced 
    plans to begin marketing portable string trimmers, traditionally 
    powered by either electricity or 2-stroke gasoline engines, that are 
    instead powered by lightweight, high-speed 4-stroke engines. This 
    company claims to achieve emission rates much lower than either current 
    2-stroke engines or engines that would meet the handheld standards 
    proposed in this rulemaking. Numerous efforts are also under way to 
    develop direct injection systems applicable to larger 2-stroke engine-
    systems that may be able to bring emissions from engines such as those 
    used for outboard marine engines down to levels equivalent to a well-
    calibrated 4-stroke engine in the same power range. However, the 
    applicability of direct injection systems to small engines used in 
    handheld applications has not yet been investigated. In developing 
    Phase 2 standards, EPA intends to revisit this issue in its entirety 
    and may combine all engines under one set of standards, modify the 
    definitions of nonhandheld and handheld equipment, as well as the 
    applicable standards, or may promulgate an entirely different 
    regulatory structure.
    
    H. Requirements Applicable to Vehicle and Equipment Manufacturers
    
        EPA is proposing to require that vehicle and equipment 
    manufacturers and importers use the appropriate handheld or nonhandheld 
    certified engine in their vehicles and equipment. Section 213 gives EPA 
    the authority to require nonroad vehicle and equipment manufacturers 
    and importers to use certified nonroad engines. EPA has determined that 
    the most effective way to ensure that certified engines are used in 
    nonroad vehicles and equipment is to require that manufacturers and 
    importers use such engines. Without such a requirement, there would be 
    no penalty for vehicle and equipment manufacturers that knowingly 
    purchase noncomplying engines, thus undercutting the entire program.
        EPA is proposing that vehicle and equipment manufacturers and 
    importers be subject to the prohibition, injunction, and penalty 
    provisions of CAA sections 203, 204, and 205, except that only the 
    nonroad engine in the vehicle or equipment, rather than the vehicle or 
    equipment itself, would need to be certified for compliance. Although 
    engine manufacturers will bear the burden of certification under this 
    proposal, the focus of enforcement will fall to some extent on vehicle 
    and equipment manufacturers because they determine whether a handheld 
    or nonhandheld engine is appropriate for use in their vehicle or 
    equipment and will ensure that those engines are certified.
        No federal paperwork or reporting burden would be imposed on 
    vehicle and equipment manufacturers by the requirement that certified 
    nonroad engines be used. This is consistent with the nonroad large CI 
    engine proposal (58 FR 28809 at 28815 (May 17, 1993) and 58 FR 51595 at 
    51597 (October 4, 1993)).
        Only new engines manufactured on or after the effective date of 
    this rule would be subject to the provisions of this rule. For example, 
    rebuilt engines originally manufactured prior to the effective date of 
    this rule would not be subject to this rule. Rebuilt engines originally 
    manufactured after the effective date of this rule would be subject 
    only to the tampering provisions. New replacement engines manufactured 
    after the effective date would be subject to this rule. EPA requests 
    comment on whether there is any need for manufacturers to produce 
    replacement engines for use in pre-1996 equipment, and the extent of 
    such a need, if any.
        Labeling requirements proposed in this notice may also impact 
    nonroad vehicle and equipment manufacturers and importers.
    
    I. Effective Date
    
        EPA is proposing an effective date of August 1, 1996 for this 
    rulemaking. This midyear effective date coincides with model changeover 
    in the small SI engine industry. Engines manufactured on or after 
    August 1, 1996 for use within the United States would have to meet the 
    standards and requirements included in this rulemaking.
        Vehicle and equipment manufacturers that use regulated engines 
    would be required to use appropriate certified nonroad engines in their 
    vehicles and equipment after August 1, 1996. EPA requests comment on 
    whether a separate effective date for nonroad vehicle and equipment 
    manufacturers should be established and, if so, whether that date 
    should be three months after the August 1, 1996 effective date for 
    nonroad engine manufacturers (that is, November 1, 1996). It appears, 
    based on best available data, that the start of large volume equipment 
    production is approximately November 1 of every year. EPA is 
    considering this separate effective date because it is concerned that 
    equipment manufacturers have small inventories of noncertified engines 
    that could not be incorporated into equipment by the August 1 effective 
    date. EPA would consider extending this flexibility to six months, that 
    is, February 1, 1997, if manufacturers could quantitatively demonstrate 
    that the increased risk of stockpiling noncertified engines by the 
    equipment manufacturers would be minimal and the inventory buildup 
    would be normal. EPA also requests comment on whether a separate 
    effective date for equipment manufacturers should be based on 
    introduction of equipment into commerce, rather than the date of 
    equipment manufacture.
        The August 1996 effective date allows engine manufacturers over two 
    years of lead time from the date of this proposal, and more than one 
    year beyond the 1995 implementation date imposed by CARB. EPA is not 
    proposing the same effective date as CARB in order to allow 
    manufacturers some lead time between the CARB and federal effective 
    dates to bring preempted engines into compliance; however, EPA requests 
    comment on the feasibility of a 1995 effective date for federal 
    standards, particularly for those engines that are not preempted from 
    state regulation.
        While EPA acknowledges the need for sufficient lead time to perform 
    research, develop testing capacity, apply emission control technology, 
    and manufacture clean engines, EPA's view is that engine manufacturers 
    have been aware for a considerable period of time that emission 
    regulations were likely to impact their products in the near future. In 
    1990, CARB was required under the California Clean Air Act (CCAA) to 
    develop emission standards for lawn and garden and utility equipment 
    engines by December of 1990. In November of 1990, Congress amended the 
    federal Clean Air Act, requiring that EPA study emissions of nonroad 
    engines and vehicles by November of 1991 and promulgate applicable 
    regulations by November of 1992 if these sources were found to 
    contribute significantly to air pollution. At a public workshop held in 
    March of 1992, EPA discussed the importance of emissions from small SI 
    engines, announcing its intent to develop applicable regulations. 
    Consequently, manufacturers have known since March 1992, at the latest, 
    that EPA was planning to develop standards applicable to their 
    products, and have already had more than two years to assess emission 
    control technologies and develop testing capacity.
        Several state and environmental interest groups have expressed 
    concerns that a 1996 effective date delays the realization of 
    reductions of in-use air pollutant emissions unnecessarily and limits 
    the ability of many states to adhere to the schedules mandated in the 
    CAA for reasonable further progress toward volatile organic compound 
    reductions from 1990 levels and for attainment of the ozone National 
    Ambient Air Quality Standard. Manufacturers have argued that a 1996 
    effective date offers too little lead time given that this proposed 
    rule covers various categories of equipment that California is 
    preempted from regulating.
        Both the Outdoor Power Equipment Institute and the Engine 
    Manufacturers Association have requested that EPA extend the effective 
    date to 1997 for all engines. The Portable Power Equipment 
    Manufacturers Association has requested that EPA extend it to 1997 for 
    engines regulated and sold in California and to 1999 for preempted 
    engines and engines discontinued in California. These industry 
    association requests are available in the docket for this rulemaking. 
    In all cases, these associations have argued that more lead time is 
    needed to apply these standards to nationwide sales.
        EPA requests comment on the impact of its proposed effective date 
    on both engine and equipment manufacturers. EPA also requests comment 
    on alternative effective dates, including phased effective dates, such 
    as 1996 for nonpreempted engines and 1997 for preempted engines, or a 
    phase-in by engine size where Class I, II, III, IV, and V engines would 
    meet the applicable standards at different times based on environmental 
    impact and lead time constraints.
    
    J. Selection of Worst Case Emitter
    
        EPA is proposing to use the criteria of highest weighted brake-
    specific fuel consumption (BSFC) over the appropriate engine test cycle 
    to determine that engine configuration within an engine family which 
    will be selected as the certification test engine. EPA believes that 
    BSFC is an appropriate criterion for selecting a worst case emitter. In 
    particular, EPA believes that an engine configuration with high BSFC 
    will generally emit higher levels of hydrocarbons and carbon monoxide 
    than a second configuration in the same engine family which has a lower 
    BSFC. EPA solicits comments on the appropriateness of weighted BSFC as 
    the criterion to be used for selecting the worst case emitter.
        EPA considered one alternative method of selecting the worst case 
    emitter. EPA considered leaving the selection of the worst case emitter 
    up to the engine manufacturer with the guideline that the engine 
    manufacturer must test that engine configuration within an engine 
    family which is most likely to exceed any emission standard. EPA 
    solicits comment on the appropriateness of this approach for selecting 
    the worst case emitter.
    
    K. Adequacy of Test Cycle
    
        The test procedure proposed in this notice is capable of predicting 
    emission reductions at the level of proposed emission standards. The 
    proposed test cycles are based on the Society of Automotive Engineers 
    (SAE) recommended practice #J1088. This is a procedure that measures 
    emissions over a number of steady state operating modes or conditions 
    (speed/load points) and determines average emissions over the entire 
    test cycle by weighting the modes relative to their likely occurrence 
    in actual use. Much of the emission assessment work to date has 
    occurred using the J1088 test procedures.
        EPA has determined that the types of technology that will be forced 
    by setting standards using the proposed test cycle will result in real 
    emission reductions in actual use. The current feasible technologies 
    are analogue in nature. Thus, when a technology is demonstrated to 
    reduce emissions on six discrete points on the engine speed/load 
    performance curve, EPA expects these technologies will perform in a 
    continuum between those test points. No large emission spikes will 
    occur under operating conditions that were not specifically tested.
        No time is available to develop a more accurate test cycle. While 
    improvements can be made and must be studied before proposing more 
    stringent emission standards that require more sophisticated 
    technologies, EPA has determined this test cycle is adequate to produce 
    the desired emission reductions expected by the proposed emission 
    standards.
        As part of the Phase 2 emission regulation process, EPA has 
    identified three test modes of the test cycle that it intends to study. 
    First, EPA wants to evaluate whether the test procedure should be run 
    using the engine's governor to control throttle. Second, EPA wants to 
    evaluate the method by which the load points used in the test cycle are 
    determined. Third, EPA wants to study the sensitivity of emissions to 
    the operating conditions not used in the test cycle to ensure emission 
    benefits are not being overlooked.
        Operating the engine directly on the governor as opposed to on the 
    throttle is allowed in the current test procedure as proposed. However, 
    it is optional and most manufacturers choose to run the test by 
    directly controlling the throttle. Manufacturers do this to reduce the 
    factors that can add variability to the test. EPA believes that, since 
    engines in use are controlled by the governor, a test cycle that 
    simulates actual operation as closely as possible has the potential to 
    predict real in-use emissions more accurately. Before such a change is 
    adopted, EPA intends to analyze the validity of this hypothesis.
        The average power generated during the test cycle has a large 
    impact on the emission result. The emission standards are based on the 
    mass emission generated for the amount of work accomplished (g/kWh). 
    Since power is a factor in how much work can be accomplished, it weighs 
    heavily in the final mass emission result. EPA wants to ensure that the 
    test cycle does not reflect how much power (and thus work) the engine 
    is capable of achieving, but is reflective of how much power the 
    equipment actually commands from the engine as it does its work. EPA is 
    concerned that the actual power drawn by equipment in actual use is 
    lower than the average power drawn from the engine during the proposed 
    test procedures. EPA does not have time to adequately verify this 
    hypothesis within the timeline of this rule, but intends to do this 
    during the Phase 2 rulemaking process.
        Finally, EPA has not verified that the operating modes in the 
    proposed test procedures are the optimal representation of what happens 
    in actual use. Any test cycle is at best an approximation of the 
    operating conditions experienced by engines in actual use. Indeed, any 
    one engine will be installed in a range of equipment types and will 
    experience a different operating environment in each application. To 
    determine if the test procedures are doing the best possible job at 
    estimating real world operation, EPA intends to collect data on a full 
    range of operating conditions that are not represented in the current 
    test cycle. Manufacturers have presented histograms of a range of 
    equipment operations such that, for purposes of this notice, the test 
    cycle is directionally acceptable. Further investigation may result in 
    a determination that the current cycle adequately covers the range of 
    operation. However, time is not available to make that determination in 
    this proposal.
        Any of the above mentioned changes to the current proposed test 
    cycle or procedures would require extensive testing and development. 
    All emission data to date is based on the proposed test procedures. 
    Before introducing any change in the test procedures EPA would have to 
    develop emission standards based on the revised procedures and would 
    have to assess emission impact on the procedures. The current timeline 
    constraints provide neither adequate time to properly assess whether 
    any of these changes would benefit the program, nor adequate time to 
    develop appropriate emission standards using the revised procedures. 
    Faced with these constraints, EPA believes that the proposed test 
    procedures are the best available to ensure early emission reduction 
    from the engines covered in this notice.
    
    L. Alternative, Oxygenated, and Reformulated Fuels
    
        EPA is not proposing the requirement of any specific type of fuel 
    to be used in engines produced to meet the proposed emission standards. 
    EPA's proposal would require that all SI engines under 19 kW meet the 
    proposed standards. This includes SI engines which run on 
    ``alternative'' fuels, such as liquid petroleum gas (LPG) and natural 
    gas. A few research papers have been published which indicate well 
    calibrated spark-ignition engines running on LPG fuel may be able to 
    meet the proposed emission standards with less difficulty than an 
    equivalent engine running on gasoline. EPA proposes to let the engine 
    manufacturer decide what type of fuel a given engine application will 
    use and not require any specific engine to use a ``cleaner'' fuel.
        EPA's proposal would not allow engines which are designed to run on 
    gasoline to perform certification emission testing using an alternative 
    fuel. EPA understands that oxygenated and reformulated gasoline fuel is 
    currently available in different areas around the United States. 
    However, availability of oxygenated and reformulated fuels varies 
    widely across the country. EPA does not have information that would 
    provide adequate assurance that the alternative fuel, and not gasoline, 
    would be used in these engines in actual use. Faced with the difficulty 
    of tracking small SI engine owners, EPA does not have adequate 
    resources, nor an adequate tracking mechanism to enforce a requirement 
    that small SI engine owners use only the specified alternative fuel. At 
    the same time, preliminary tests performed on small engines using 
    reformulated and oxygenated fuels show approximately a three to five 
    percent improvement in exhaust emission levels of CO and total HC. See 
    the draft RSD in the docket for further discussion of this issue. 
    Reformulated fuel was designed to lower HC levels from on-highway 
    vehicles, primarily engines with fuel injection and catalytic 
    convertors. EPA is not convinced it can reasonably expect the same type 
    of benefit from carbureted single and two-cylinder engines. EPA 
    solicits comment on the feasibility of requiring small SI engines to 
    run only on oxygenated or reformulated fuels.
    
    M. HC + NOX Standard for Class I and II Engines
    
        EPA is considering two options for setting Class I and II HC and 
    NOx standards. Option 1 would consist of setting a combined standard 
    for emissions of HC and NOX for Class I and II engines. Under 
    option 2, EPA would set separate HC and NOX emission levels for 
    Class I and II engines.
        Regardless of which option EPA chooses, it anticipates that 
    NOX emission rates from engines meeting this proposed rule's 
    standards will be generally higher than those extremely low NOX 
    levels emitted by current engines. The Agency views this as an 
    inevitable consequence of the level of HC reduction being achieved in 
    this rule. Furthermore, EPA estimates that the resulting increase in 
    NOX emission inventories would be slight enough in this particular 
    case to be warranted given the much greater decrease in HC emission 
    inventories. See ``VI. Environmental Benefit Assessment'' in this 
    preamble.
        Nonroad small SI engines currently operate on an extremely rich 
    fuel and air mixture--in other words, one that contains a very high 
    proportion of fuel relative to that used by, for example, automotive 
    engines. Because this results both in less complete combustion and much 
    lower peak combustion temperatures, exhaust concentrations of unburned 
    HC are extremely high, while concentrations of NOX are extremely 
    low. As a result, small SI engines contribute appreciably to HC 
    emission inventories, but very little to NOX emission inventories.
        In the 19 ozone nonattainment areas studied by EPA in the 1991 
    Nonroad Study, emissions from all nonroad sources, on average, 
    represented ten percent of total HC emissions and 17 percent of total 
    NOX emissions. Of those contributions, small SI engines 
    contributed an average of 50 percent of total HC from nonroad sources, 
    but only one percent of total NOX. In contrast, nonroad large CI 
    engines, for which EPA has proposed NOX standards, contributed an 
    average of ten percent of total HC from nonroad sources and 75 percent 
    of total NOX. Consequently, EPA's primary focus in developing 
    emission standards for small SI engines is achieving sizeable 
    reductions in HC emission rates.
        Given the extremely rich operation of small SI engines, EPA does 
    not believe that small engine technology is available to prevent 
    NOX levels from increasing while HC levels decrease substantially 
    within the short lead time period set forth in this proposal. While it 
    may be possible in some isolated cases to employ automotive-type 
    emission control systems relying on closed-loop operation and three-way 
    catalytic converters, the state of development of such technology is 
    not ready for small engine application in the short lead time proposed. 
    Furthermore, the sensitivity of such systems to in-use deterioration 
    and malmaintenance would greatly lessen their in-use effectiveness 
    given the state of the service industry available to these engines.
        EPA has estimated that by the year 2020, when current equipment 
    turnover is projected, the proposed emission standards would result in 
    approximately a 32 percent reduction in HC emission from current 
    levels, or 356,710 tons per year. Under the same timeframe, in-use 
    NOX emission rates would be expected to increase 1.36-fold, or 
    34,000 tons per year. Given the magnitude of the relative contribution 
    of these small SI engines to HC and NOX emission inventories in 
    ozone nonattainment areas, EPA believes this projected decrease in HC 
    and increase in NOX levels would be consistent with EPA's 
    statutory mandate that emissions standards reflect the greatest 
    emission reductions achievable. This is especially the case in light of 
    the fact that this rule would increase the national NOX inventory 
    by about one quarter of one percent, while EPA's nonroad large CI 
    engine regulations would reduce the national NOX inventory by 
    about four percent.
        EPA anticipates that, given the magnitude of the HC reduction 
    proposed, emission rates would be marginally sensitive enough that 
    near-term compliance with separate emission standards at the proposed 
    level of stringency could be difficult in some cases, whereas 
    compliance with a combined standard is expected to be achievable.
        However, EPA is concerned that establishing a combined standard 
    might be viewed as setting a precedent for future rulemakings. EPA does 
    not intend to establish any such precedent, and is considering a 
    combined standard for Phase 1 only due to the present lack of available 
    data for setting a separate NOX standard, the current lack of 
    technology for achieving NOX reductions simultaneously with HC 
    reductions for the subject engines and vehicles, the need to achieve HC 
    reductions as soon as possible under the Phase 1 rule, and the desire 
    to harmonize with California's standards.
        EPA requests comment on a combined standard (option 1). EPA also 
    requests comments and data supporting separate numerical standards for 
    HC and NOX (option 2). Based on information currently available to 
    EPA, if it were necessary to develop separate standards, the NOX 
    standard would be approximately 136 percent higher than current new 
    engine levels, while the HC standards would be approximately equal to 
    the difference between those levels and the proposed HC+NOX 
    standards.
    
    N. CO Standard for Handheld Engines Over 50 cc
    
        EPA is concerned that the CO levels for handheld engines be kept as 
    low as possible. The operators of equipment using these engines are in 
    close proximity to the exhaust pipe. The Class V engines are a large 
    concern. The majority of these engines are used on large commercial 
    chain saws used in logging operations. The high power and high load 
    factors associated with this equipment mean the operator is potentially 
    exposed to a high CO rate from the engine and could experience high CO 
    intake during operation.
        EPA is proposing to limit CO emissions from large (Class V) 
    handheld engines to 402 g/kWh. In comparison, smaller (Class III, IV) 
    handheld engines would be required to meet the higher standard of 804 
    g/kWh. The larger Class V engines have technical advantages over 
    smaller engines, with respect to fuel metering and combustion chamber 
    boundary layer conditions, that would allow them to achieve these lower 
    levels of CO emission. This technical rationale is discussed at length 
    in the draft RSD in the docket. In addition to the technical rationale 
    that the Class V engines are capable of lower CO emission levels, a 
    number of engines were tested by the Portable Power Equipment 
    Manufacturers Association (PPEMA) and an individual manufacturer, 
    modified for a six percent enleanment over current production 
    calibration. Approximately 20 to 30 percent of these engines met the 
    402
    g/kWh CO standard, achieving average CO levels of eight percent below 
    the standard. The remaining engines tested did not meet either the HC 
    or the CO emission standards. (See data in the draft RSD.) EPA observed 
    that, in general, port design may affect the ease with which engines 
    can meet emission standards. EPA requests comment and data on whether 
    there is a supportable technical rationale why it would not be feasible 
    to further optimize these engines to bring both the HC and CO emissions 
    into line with the engines capable of achieving the proposed standards.
        PPEMA has argued that the 402
    g/kWh level is too stringent, but did not focus on Class V engines at 
    the time California rules were being considered since its members 
    anticipated limited regulation of the Class V engines in California due 
    to preemption of many of the products in which these engines are used. 
    In a letter to EPA, a copy of which is included in the docket for this 
    rulemaking, PPEMA suggests that a standard of 603 g/kWh would be more 
    appropriate. EPA would need further data and information that 
    establishes 603 g/kWh as the appropriate technical limit and addresses 
    the need for this higher CO standard as noted above.
        Based on the data currently available, EPA does not see the need 
    for the higher standard and believes that the proposed standard is 
    achievable. However, EPA is requesting additional information and data 
    that would verify the need for the higher standard and justify why all 
    engines cannot be designed to meet the CO levels achieved by the 20 to 
    30 percent of engines tested by PPEMA that met all proposed standards.
    
    O. Cap on Noise
    
        EPA is proposing to require that engine noise levels not increase 
    as a result of this rulemaking. The type of engine changes which EPA 
    believes will be used to meet the proposed exhaust gaseous emission 
    standards should not increase engine noise above current levels. EPA is 
    aware that several European nations currently have sound level 
    standards for different classes of nonroad equipment, some of which are 
    powered by SI engines less than 19 kW. EPA lacks the necessary 
    information to determine if regulating engine noise without regard to 
    the type of equipment in which the engine will eventually be used is a 
    sensible technical approach. EPA requests data and comments on this 
    issue.
    
    P. Applicability of In-Use Standards
    
        The proposed rule does not require that small engines meet in-use 
    standards over a useful life period for several reasons. First, limited 
    emission testing of in-use engines has been performed. Additional data 
    will be provided by the in-use testing program described in ``IV.C. 
    Program Description and Rationale.'' Second, EPA does not believe that 
    emission controls proposed for Phase 1 will experience significant 
    deterioration beyond normal engine deterioration, although this area 
    needs more research. EPA does acknowledge its responsibility to achieve 
    enforceable reductions of in-use emissions and plans to develop such 
    measures in its long-term Phase 2 program.
        Until such measures are developed, EPA proposes to maintain 
    regulatory language in the Phase 1 rule that commits EPA to setting in-
    use standards and useful life periods by April 1997. In developing 
    Phase 2 regulations, EPA intends to amend this language, replacing it 
    with regulatory language specifying programs that are developed to meet 
    this commitment.
        EPA solicits comment on the lack of in-use standards and on the 
    appropriate level of in-use standards, useful life period, and 
    enforcement measures if EPA were to make these a requirement of Phase 
    1. EPA also invites comment on the regulatory language in the Phase 1 
    rule that commits EPA to developing these requirements by April 1997. 
    This language states, ``A useful life period for engines subject to the 
    provisions of subpart A of this part will be set by the Agency and will 
    be promulgated no later than the year 1997.''
    
    Q. In-Use Testing Requirement
    
        This proposal requires that manufacturers procure and test a sample 
    of in-use engines and report the results to EPA. In developing this 
    program, EPA considered manufacturer suggestions that any in-use 
    testing program be conducted jointly between EPA, manufacturers, and 
    manufacturers' organizations. EPA is concerned that a joint program 
    would not as efficiently address the goals of the proposed in-use 
    testing program.
        EPA is proposing the in-use testing requirement with two main goals 
    in mind. Primarily, EPA believes that a critical element in the success 
    of its nonroad program is assuring that manufacturers build engines 
    that continue to meet emission standards beyond the certification and 
    production stages. By requiring manufacturers to test and report 
    results, EPA expects that manufacturers would act responsibly to avoid 
    or correct in-use emission problems.
        EPA's authority to recall engines which do not comply with emission 
    standards in use provides an important incentive to on-highway 
    manufacturers to design and build durable engines and vehicles. 
    However, at this time, EPA has limited data by which to propose in-use 
    standards for small SI engines under section 213(d) of the CAA, 
    subjecting nonroad engine manufacturers to the requirements of section 
    207(c) of the CAA. Because EPA is not proposing to establish in-use 
    emission standards in this rulemaking, it is necessary to require that 
    manufacturers test in-use engines to gain important knowledge about the 
    emission deterioration of their engines and report the results to EPA. 
    EPA expects that this knowledge will be critical to developing more 
    durable emission control systems and achieving better in-use compliance 
    with Phase 2 engines.
        An auxiliary outcome of this Phase 1 testing program would be that 
    manufacturers, by working closely with EPA to evaluate in-use emissions 
    and identify solutions to problems, would be preparing for the Phase 2 
    in-use compliance program. This Phase 1 testing program would permit 
    issues associated with a variety of maintenance and use conditions to 
    be identified and resolved prior to Phase 2.
        As stated previously, EPA is concerned that these goals may not be 
    as fully achieved with joint testing programs involving several 
    manufacturers and their respective organizations. By requiring direct 
    communication with EPA, manufacturers would have to individually 
    provide test data showing in-use performance. EPA's experience has been 
    that aggregate data (sorted by organizations and stripped of engine 
    identification) is not effective in identifying specific in-use 
    problems. The generated Phase 1 in-use data would improve estimates of 
    in-use emissions, thereby enhancing the basis for emission inventories 
    used to support the State Implementation Plan (SIP) development 
    process.
        Given the critical feedback the in-use testing program would 
    provide, EPA believes it is compelled to ensure the fulfillment of the 
    obligation to perform in-use testing. For engine families where in-use 
    testing would be required, certification is proposed to be conditioned 
    upon the completion of a number of in-use tests as agreed upon by EPA 
    and the manufacturer at the time of certification. Completion of the 
    number of valid in-use tests as agreed, regardless of the test results, 
    would satisfy this condition.
        Under this proposal, a manufacturer's failure to fully execute the 
    in-use tests would be considered a failure to satisfy the conditions 
    under which the certificate was issued. An engine would be considered 
    to be covered by the certificate only if the manufacturer fulfilled the 
    conditions upon which the certificate was issued. Thus, failure to 
    satisfy the conditions of the certificate could subject a manufacturer 
    to the imposition of civil penalties. However, EPA recognizes that a 
    manufacturer, notwithstanding its best efforts, might fail to perform 
    the required testing due to circumstances beyond its control. Thus EPA 
    would consider all relevant factors when determining whether to view an 
    engine as not being covered by a certificate based on failure of a 
    manufacturer to fully execute the test program condition of the 
    certificate.
        EPA requests comment on the proposed in-use testing program.
    
    R. Absence of Averaging, Banking, and Trading Programs
    
        EPA is not proposing an averaging, banking, and trading program 
    (ABT) for small SI engines at this time. ABT programs, which EPA uses 
    in its on-highway heavy-duty engine program and proposed for the 
    nonroad large CI engine program, provide manufacturers flexibility in 
    meeting the emission standards. EPA is increasingly using market-based 
    incentive programs such as ABT because such programs can reduce the 
    cost of controlling emissions. An ABT trading program can also reduce 
    the burden of regulation on small manufacturers by providing them 
    flexibility in meeting requirements.
        At this time, EPA has not been able to construct an ABT program, 
    given the uncertainties surrounding projected in-use emission levels. 
    These uncertainties will be resolved as part of the Phase 2 regulatory 
    negotiations. However, as part of the requirements of approving an ABT 
    program, EPA must know the in- use emission characteristics of engine 
    families in order to implement an ABT standard, unless all engine 
    families deteriorate at the same rate.
        The lifetime emissions of engine families must be averaged together 
    in order to compute the average emission level of a manufacturer's 
    product line. Use of lifetime emissions is necessary because it may be 
    the case that the emissions of one type of engine deteriorate at a 
    higher rate than another type, or a smaller engine may deteriorate at a 
    higher rate than a larger engine of the same type. EPA is not in a 
    position to determine what the in-use emission level is presently or 
    would be under this Phase 1 regulation. EPA's initial assessment is 
    that the emissions of these engines deteriorate somewhat over time and 
    likely deteriorate at different rates between engine families, but more 
    research is necessary. However, even if engine families deteriorate at 
    different rates, if such deterioration is not systematically biased, it 
    may not undermine the validity of an ABT program. EPA requests comment 
    on this point.
        Phase 2 will directly assess in-use emission characteristics of 
    engine families and incorporate enforcement of in-use emission levels. 
    Once in-use emission levels are known with more confidence, EPA expects 
    that market-based programs such as ABT will be viewed favorably by the 
    regulatory negotiation committee during policy development.
        EPA requests comment on the absence of an ABT program.
    
    S. Engine Manufacturer Requirement--Disclosure of Maximum Exhaust 
    Pressure and Minimum Inlet Pressure
    
        The design of the exhaust system can influence emissions. Most 
    small engines are supplied with both an air inlet system and an exhaust 
    system which are tested as part of the engine package, and the entire 
    package is used by the equipment manufacturer. However, some engines 
    are designed to be installed in a chassis with more complex packaging 
    requirements where the equipment manufacturer may supply and/or install 
    the exhaust system, or part of it, and even the air inlet system. In 
    these latter cases, EPA is considering a requirement that the engine 
    manufacturer would need to specify to the equipment manufacturer the 
    maximum exhaust pressure and the minimum inlet pressure, and the 
    equipment manufacturer would be required to adhere to those 
    specifications. EPA requests both engine and equipment manufacturer 
    comments regarding this issue.
    
    T. Direct Health Effects of Air Toxics and CO
    
        In addition to the concern of the role of HC and CO in ozone and CO 
    nonattainment, EPA is concerned about direct health effects of air 
    toxics and CO exposure. The concentrations and direct health effects of 
    toxic pollutants in exhaust are especially important because the 
    operator of a small SI engine application is typically near the 
    equipment as it functions. In some applications, the operator must be 
    adjacent to the exhaust outlet and is in the direct path of the exhaust 
    as it leaves the engine. See ``VI. Environmental Benefit Assessment'' 
    for further discussion of this issue. The Agency requests additional 
    information on the effects of air toxics and CO exposure associated 
    with the use of small SI engines.
    
    U. Catalyst Durability
    
        Relative to all other types of emission-related engine components, 
    catalysts are unique in that:
         Relatively small changes in chemical and/or physical 
    characteristics of a catalyst can result in very large deleterious 
    changes in operational characteristics.
         The engine manufacturer is not likely to be involved in 
    the design or fabrication of the catalysts nor be able to verify the 
    acceptability of vendor-supplied catalysts by means of the simple 
    checks and tests that are adequate for other engine components.
         The satisfactory operational durability of catalysts are 
    much more dependent on the catalyst manufacturer's proprietary 
    techniques and processes than is the case with other emission control 
    system components.
         Since it is the last component in the emission control 
    system, a catalyst can compensate for sub-standard performances by 
    other emission control components, but it is not itself supported by 
    any other back-up component that is able to compensate for a reduction 
    in catalyst performance capability.
         Substantial reductions in performance can result from:
    
    --Abrasion or fracturing as a result of relative motion between the 
    catalyst and its protective outer metal jacket,
    --Poisoning as a result of fuel contaminants (such as lead),
    --Glazing as a result of excessive quantities of lubricating oil in the 
    exhaust, and
    --Thermal degradation as a result of exposure to excessively high 
    temperatures for prolonged periods.
    
        Catalytic converters designed for small SI engines in the short 
    term will be low efficiency catalysts to address safety concerns. The 
    catalysts designed for potential Phase 1 use would have conversion 
    efficiencies on the order of approximately 30 percent for HC and CO 
    emission. The design constraint that dictates these low efficiencies is 
    the need to limit the increase in exhaust temperatures, since the 
    exhaust is in close proximity to the operator in handheld equipment. 
    Efficiencies much higher than 30 percent begin to generate exotherms 
    that can substantially increase exhaust temperatures. Since the 
    industry has not yet developed the necessary solutions, such as 
    creative small-scale insulation approaches, to control the added 
    temperature, only low efficiency catalysts would be available for Phase 
    1 use.
        While adequate durability of catalysts is a concern relative to 
    catalytic converters used in on-highway engine applications, EPA is 
    less concerned with the emission impact of failures of the catalytic 
    converters expected to be used for engines regulated by this rule. This 
    is because the conversion efficiency of catalysts used in small SI 
    engines would not exceed approximately 30 percent for reasons discussed 
    in the previous paragraph. Faced with this constraint, an engine 
    manufacturer would need to modify its base engine to realize 
    substantial emission reduction of engine-out emissions even before the 
    exhaust was converted further by the catalytic converter. Should such a 
    low efficiency catalyst fail in use, the increase in emissions would 
    not be as large as occurs when a high efficiency on-highway vehicle 
    catalyst fails.
        The preceding discussion underscores the need for some means to 
    validate the adequacy of catalysts that would be added to engines to 
    provide compliance with the emission standards during in-use operation. 
    Various approaches could be used for ensuring that the ``long term'' 
    conversion capabilities of catalysts would be adequate. For example, 
    certification engines could be tested with catalysts which had been 
    subjected to some type of ``aging'' process to substantiate that the 
    catalysts were adequately designed and fabricated. Alternatively, 
    certification engines could be tested with new catalysts that had been 
    proven to be satisfactory by meeting the requirements of a catalyst 
    certification procedure that would be separate from the engine emission 
    certification test.
        The main advantage of a validation approach involving the use of 
    ``aged'' catalysts on certification engines would be its simplicity. 
    The aging process would be carried out by either the engine 
    manufacturers or the catalyst vendors. In either case, there would be 
    no requirements for special catalyst performance testing and, hence, no 
    need for the establishment of performance standards that would be 
    needed for evaluating the test results.
        The main disadvantage of this approach is the possible negative 
    impact on catalyst usage that might result from a Phase 1 certification 
    process which imposed durability testing requirements on catalysts but 
    not on certification engines or any other engine components involved in 
    their construction. On one hand, the dependence of successful 
    certification of engine families on the performance capabilities of 
    aged catalysts might result in engine manufacturers being reluctant to 
    use catalysts to meet the applicable emission standards. Also, given 
    that there is limited field data on small engine catalysts, it would be 
    extremely difficult to design a fair aging procedure that could be 
    evaluated by the certification engine test and accompanying emission 
    standards.
        Such possibly adverse results would be avoided by the engine 
    manufacturer's use of a new catalyst that was ``certified'' by the 
    supplier or the engine manufacturer as having design and fabrication 
    details that resulted in specific long-term conversion performance 
    capabilities. This approach would have the disadvantage of being more 
    complicated in that it additionally involves the establishment of 
    limits on the amount of efficiency loss that would be acceptable and 
    would require a test procedure for determining compliance with such 
    limits.
        As a consequence of concerns regarding possible negative impacts on 
    catalyst development for small engines that might result from a 
    provision requiring the certification of engines with aged catalysts, 
    EPA is not proposing such a requirement in this notice. Instead, EPA is 
    proposing that for systems utilizing catalysts, the certification 
    engine configuration to be tested must be equipped with a new catalyst 
    of a design that has been ``certified.'' A ``certified'' catalyst 
    design would be one which had successfully met the requirements of a 
    separate catalyst durability demonstration procedure which is described 
    in more detail in the following paragraphs. This approach ensures that 
    durable catalysts are used on small engines while avoiding excessive 
    requirements that could discourage the development of very promising 
    catalyst technology.
        Comments regarding this proposal are requested. Also requested are 
    comments regarding the advantages and disadvantages of this 
    requirement, as well as the alternative requirement for the use of 
    preconditioned or aged catalysts during engine emission certification 
    testing.
        The use of an oven exposure procedure for evaluating catalyst 
    resistance to thermal degradation is proposed in this notice. This 
    procedure would involve the heating of the test catalyst in air to a 
    temperature of 1,000  deg.C for six hours. Prior to heating the 
    catalyst to 1,000  deg.C, an optional pre- heating procedure is 
    proposed to be allowed to remove the ``green'' effect of the catalyst. 
    This optional procedure would consist of heating the catalyst to no 
    more than 500  deg.C for no more than two hours.
        The oven exposure procedure described above is proposed in lieu of 
    procedures which involve exposure to synthetic or actual exhaust gas 
    mixtures because EPA believes that the oven aging procedure 
    aggressively and directly stresses the catalyst and is the best method 
    for assessing the most major catalyst durability concern: thermal 
    stability. Another advantage of this method is that it is much less 
    complex than the other exposure procedures.
        For example, in the case of the procedure which involves exposure 
    to synthetic exhaust gas mixtures, information is lacking regarding the 
    most appropriate test parameters, such as the temperature of the 
    mixtures and the duration of the exposure. Similarly, with respect to 
    the procedure which involves exposure to actual exhaust gas mixtures, 
    information is needed regarding a number of test variables that are 
    related to the engine that is used to generate the exhaust gas mixture, 
    such as its combustion cycle and power output, the manner in which it 
    is operated and the operating times that are involved in each phase of 
    the operating cycle.
        General comments regarding the applicability and suitability of the 
    proposed oven exposure procedure are requested. Specific comments are 
    also requested regarding variation in the procedure, such as: The use 
    of an oven atmosphere other than air; if flow through the catalyst is 
    recommended; and the composition and flow rate of the gas or gaseous 
    mixture that is used.
        Regardless of which method is used to age the catalyst, some means 
    must be used to determine the effects of the aging process. With 
    respect to the intended purpose of this process, the most 
    straightforward evaluation would involve the determination of the 
    extent to which the performance characteristics of the test catalyst 
    had been adversely affected. Of particular significance would be the 
    adverse effect on the catalyst's conversion capabilities with respect 
    to the oxidation of HC and CO and/or the reduction of NOX.
        The use of a procedure which uses a synthetic exhaust gas mixture 
    for evaluating the effects of thermal stressing is being proposed for 
    several reasons. One of the main reasons is the relative simplicity of 
    such a procedure. For example, it would not involve the questions 
    regarding the in-use representativeness of test parameters, such as the 
    temperature of the mixture and the duration of the test, that arise 
    when a synthetic exhaust gas mixture is used for actually thermally 
    stressing a catalyst. For evaluation purposes, any fixed temperature 
    which allowed the conversion reactions of interest to occur could be 
    specified. The specification of a particular exposure time would not be 
    required since the conversion efficiency existing as a result of the 
    previous thermal stressing would be involved rather than a time-related 
    change in efficiency. Furthermore, a procedure which used synthetic 
    exhaust gas would be simpler than a procedure that used actual exhaust 
    gas. Using synthetic exhaust gas mixtures alleviates the need for 
    detailed information not readily available at this time. Another reason 
    for proposing the use of synthetic exhaust gas mixtures is the 
    standardization that results; all catalysts would be aged under the 
    specific conditions that are proposed in subpart E of the proposed 
    regulations. The composition of the synthetic exhaust gas mixture that 
    is specified in this subpart is comparable to compositions of synthetic 
    exhaust gas mixtures currently used by catalyst manufacturers for 
    testing related to the kinds of engines covered by the proposal.
        Comments are solicited concerning these specifications, 
    particularly with regard to the chemical composition and temperature of 
    the synthetic exhaust mixture and its flow rate as it enters the test 
    catalyst.
        A fixed catalyst efficiency loss limit of 20 percent for HC, CO, 
    and NOX is proposed in this notice on the basis of on-highway 
    experience and the absence of information at this time regarding the 
    conversion efficiencies that will be used with small engines. To 
    illustrate this loss limit, a catalyst with initial HC conversion 
    efficiency of 50 percent would be required to maintain at least a 
    conversion efficiency of 40 percent after thermal aging.
        Comments are requested regarding the use of a different fixed 
    deterioration limit. Comments are also requested regarding the relative 
    advantages and disadvantages of one fixed limit versus several limits 
    that are proportional to initial conversion efficiency.
    
    V. Test Procedure Requirements
    
        EPA received a technical review of an early draft of the test 
    procedure from the Small Engine Committee of the Society of Automotive 
    Engineers (SAE) in September 1993. EPA requests comment on several 
    points mentioned in SAE's comments.
        EPA is proposing that during each mode of the emission test cycle, 
    engine manufacturers collect and analyze exhaust constituents and 
    measure engine parameters during a period of time referred to as the 
    ``sampling period.'' EPA is proposing that the sampling period be a 
    minimum of four minutes long. The SAE recommended test procedure J1088 
    recommends the sampling period be ``* * * at least two minutes. Longer 
    averaging times may be required to ascertain the true time averaged 
    emissions if data variability over time is significant.'' Based on 
    EPA's experience with several small (two to four kW) engines, a two-
    minute averaging time for idle modes is not sufficient to make accurate 
    fuel flow measurements. EPA requests comment on the appropriateness of 
    a four minute averaging time, including any available test data to 
    substantiate an averaging time less than four minutes.
        EPA is proposing that for the final calculation of the brake-
    specific emission rate (gr/kWh), any power measured during the idle 
    mode not be included in the calculation for the reported brake-specific 
    emission rate. EPA believes the idle mode is, by definition, that 
    engine operating mode during which no useful work is performed. Any 
    power measured during this mode is a result of the frictional losses 
    resulting from the dynamometer. EPA is concerned that an engine 
    manufacturer using an inappropriately large dynamometer with a large 
    frictional loss would not provide an accurate measurement of the engine 
    idle mode. EPA believes it is inappropriate to include power generated 
    by the engine to overcome the windage losses of the dynamometer in the 
    calculation of emissions during the idle mode. EPA requests comment on 
    the appropriateness of including power measured by the dynamometer in 
    the calculation of the final brake-specific emission rate.
    
    W. Duration of Certificates of Conformity, Definition of Model Year, 
    Annual Production Period
    
        EPA is considering adopting one of the following three options for 
    defining model year, annual production period, and duration of the 
    certificate of conformity. Regardless of the option selected, EPA is 
    also proposing in this notice that it would be a prohibited act to 
    introduce an uncertified small SI engine into commerce after August 1, 
    1996. Furthermore, it would be a prohibited act to introduce a specific 
    model year engine into commerce prior to or after the model year for 
    which the certificate of conformity was issued and in effect. EPA 
    requests comment on each of these three alternatives.
        Option 1: EPA would incorporate the on-highway definition of model 
    year, annual production period, and duration of a certificate of 
    conformity.
        The model year would include January 1 of the calendar year for 
    which it is designated and would not include a January 1 of any other 
    calendar year. Thus, the maximum duration of a model year would be one 
    calendar year plus 364 days.
        The ``annual production period'' for any specific model within an 
    engine family would begin either: (1) When such an engine was first 
    produced, or (2) on January 2 of the calendar year preceding the year 
    for which the model year was designated, whichever date was later. The 
    annual production period would end either: (1) When the last engine was 
    produced, or (2) on December 31 of the calendar year for which the 
    model year was named, whichever date was sooner.
        A certificate of conformity would be issued to cover engines 
    introduced into commerce for a single model year. Under option 1, the 
    1997 model year certificate could cover production between January 2, 
    1996 and December 31, 1997, although engines regulated under this 
    proposal would be manufactured after August 1, 1996.
        Interested parties may wish to consult OMS Advisory Circular A/C 
    No. 6B, issued December 31, 1987, which summarizes the on-highway 
    treatment of model year, annual production period, and duration of the 
    certificate of conformity. A copy of the circular has been placed in 
    the docket for this rulemaking.
        Option 2: This option represents a variation of Option 1. EPA 
    believes that the dates selected for the commencement of model year and 
    the annual production period more closely parallel the experience of 
    the small engine industry.
        Under option 2, the model year would include August 1 of the 
    preceding calendar year for which it was designated and would not 
    include an August 1 of any other calendar year. The maximum duration of 
    a model year would remain one calendar year plus 364 days.
        The ``annual production period'' for a specific model within an 
    engine family would begin either: (1) When such an engine was first 
    produced, or (2) on August 2 of two calendar years preceding the year 
    for which the model year was designated, whichever date was later. The 
    annual production period would end either: (1) When the last engine was 
    produced, or (2) on July 31 of the calendar year for which the model 
    year was named, whichever date was sooner.
        The certificate of conformity would be issued to cover production 
    for a single model year. For example, the 1997 model year could cover 
    production between August 2, 1995 through July 31, 1997.
        The proposed extended coverage period described in options 1 and 2 
    for a certificate of conformity (that is, up to one year plus 364 days) 
    is primarily intended to allow flexibility in the production of new 
    models. Under no circumstances should it be interpreted that existing 
    models could ``skip'' yearly certification by pulling ahead the 
    production of every other model year. While this situation, to our 
    knowledge, has not occurred in the on-highway program in the past, a 
    practice of producing small SI engines for a two year period would 
    violate Congress' intent of annual certification based upon an annual 
    production period. EPA is not currently proposing rules for how to 
    determine when abuse has occurred since this has not been a problem to 
    date. However, manufacturers should note EPA's concern in this area and 
    should use normal yearly production periods for existing models.
        Option 3: Under this option, the certificate of conformity would be 
    issued to cover production from August 1 of a given calendar year 
    through July 31 of the subsequent calendar year for which it was 
    issued. EPA would retain the model year concept found in on-highway 
    programs but would define it as follows: ``Model year means the 
    manufacturer's annual production period which includes August 1 of a 
    given calendar year through July 31 of the subsequent calendar year.'' 
    Thus the maximum duration of a model year would be 365 days.
    
    VI. Environmental Benefit Assessment
    
        National Ambient Air Quality Standards (NAAQS) have been set for 
    criteria pollutants which adversely affect human health, vegetation, 
    materials, and visibility. Concentrations of ozone (O3) are 
    impacted by HC emissions and, to a lesser extent, emissions of CO. 
    Ambient concentrations of CO are, of course, impacted by CO emissions. 
    EPA has determined that the standards set in this rule would reduce 
    emissions of HC and CO and, despite also increasing emissions of 
    NOX, help most areas come into compliance with the NAAQS for ozone 
    and, to a lesser extent, CO. The following provides a summary of the 
    emission reductions expected and the health effects of HC components, 
    CO, and ozone. A discussion of the roles of HC and NOX in ozone 
    formation is also presented. The underlying analysis is described in 
    greater detail in the draft RSD, a copy of which is in the public 
    docket for this rulemaking.
    
    A. Estimated Emissions Impact of Proposed Regulation
    
        The emission standards proposed in today's action should reduce 
    average per-engine HC and CO emission from small SI engines by 32 
    percent and 14 percent, respectively, by the year 2020, when complete 
    fleet turnover is projected. This would result in annual nationwide 
    reductions of roughly 350,000 tons of HC and 2,000,000 tons of CO by 
    the year 2020. In-use NOX emission rates are expected to increase, 
    roughly, from 7,000 to 34,000 tons per year. This increase represents 
    one quarter of one percent of the national NOX inventory, and is 
    small compared to the substantial NOX reductions achieved in the 
    nonroad large CI proposal (58 FR 28809).
        In addition to control of HC, the proposed standards should be 
    effective in reducing emissions of air toxics, including benzene and 
    1,3-butadiene. However, the magnitude of reduction would depend on 
    whether the control technology reduces the individual toxics in the 
    same proportion to total hydrocarbons.
        These emission reduction estimates for HC and CO are based on 
    population projections using estimates of annual engine consumption 
    (that is, sales), engine attrition (that is, scrappage), activity 
    indicator, and current and proposed in-use emission factors. Data on 
    activity indicators and the baseline emission factors were obtained 
    from the Nonroad Study. Estimates of annual engine consumption for 
    years from 1973 to 1992 were based on engine consumption data available 
    from the PSR databases and industry data from OPEI,\7\ PPEMA,\8\ and 
    Booz Allen & Hamilton.\9\ Future consumption estimates are for the most 
    part based on estimates of population growth for the United States. 
    Attrition rates (that is, likelihood, as a function of engine age, that 
    an engine remains in service) for all engines included in this analysis 
    were developed on the assumption that equipment attrition is described 
    by a two-parameter form of the Weibull cumulative distribution 
    function.
    ---------------------------------------------------------------------------
    
        \7\Outdoor Power Equipment Institute's historical national 
    shipment data.
        \8\Portable Power Equipment Manufacturers Association's shipment 
    data for selected equipment.
        \9\Booz Allen & Hamilton, 1990 Report to California Air Resource 
    Board.
    ---------------------------------------------------------------------------
    
        For the analysis summarized in Tables 2 and 3, the emission 
    inventories were developed for the five regulated engine classes as 
    well as for all pieces of equipment using engines covered by this 
    proposed rule. Using estimated engine consumption and attrition, EPA 
    projected the total in-service engine population for each year from 
    1973 through 2020. EPA projected the total annual nationwide HC, CO, 
    and NOX emissions from small SI engines included in the current 
    proposal under the baseline (that is, no controls applied) and 
    controlled scenarios.
        For the controlled scenario, EPA assumed that new engines sold 
    beginning in 1996 would meet the proposed standards. For both 
    scenarios, in-use emission rates were determined so as to account for 
    deterioration by adjusting the difference between new engine and in-use 
    engine emission rates by a factor which is a function of age of the 
    specific engine and its B-50 or median life expressed in years.
    
                                   Table 2.--Projected Annual Nationwide HC Emissions                               
                                                      [tons/year]                                                   
    ----------------------------------------------------------------------------------------------------------------
                                                                                                            Percent 
                            Year                              Baseline      With proposed  Reduction from      of   
                                                                              controls        baseline      baseline
    ----------------------------------------------------------------------------------------------------------------
    1990.................................................         729,458         729,458  ..............  .........
    1996.................................................         813,575         733,597          79,978      9.8  
    2000.................................................         871,723         618,876         252,847     29.0  
    2005.................................................         938,275         636,769         301,506     32.1  
    2010.................................................       1,002,164         676,759         325,405     32.5  
    2015.................................................       1,058,864         716,899         341,965     32.3  
    2020.................................................       1,112,630         755,920         356,710     32.0  
    ----------------------------------------------------------------------------------------------------------------
    
    
                                   Table 3.--Projected Annual Nationwide CO Emissions                               
                                                       [tons/year]                                                  
    ----------------------------------------------------------------------------------------------------------------
                                                                                                            Percent 
                            Year                              Baseline      With proposed  Reduction from      of   
                                                                              controls        baseline      baseline
    ----------------------------------------------------------------------------------------------------------------
    1990.................................................       8,109,097       8,109,097  ..............  .........
    1996.................................................       9,499,739       9,112,559         387,180      4.1  
    2000.................................................      10,384,195       9,107,279       1,276,916     12.3  
    2005.................................................      11,379,821       9,807,781       1,572,040     13.8  
    2010.................................................      12,320,136      10,591,294       1,728,842     14.0  
    2015.................................................      13,153,741      11,303,418       1,850,323     14.1  
    2020.................................................      13,939,000      11,977,377       1,961,623     14.1  
    ----------------------------------------------------------------------------------------------------------------
    
    B. Health and Welfare Effects of HC Emissions
    
        The focus of today's action is reduction of HC emission as a part 
    of the solution to the ozone nonattainment problem. However, direct 
    health effects are also a reason for concern due to direct human 
    exposure to emissions from small SI engines during operation of 
    equipment using such engines. Of specific concern is the emission of 
    air toxics. In some applications, the operator must be adjacent to the 
    exhaust outlet and is in the direct path of the exhaust as it leaves 
    the engine. Today's regulations should be effective in reducing air 
    toxics such as benzene and 1,3-butadiene.
        Based on data from the Nonroad Study, the exhaust and crankcase 
    emissions from a 2.9 kW lawnmower with a 4-stroke engine contain 3.5 
    grams of benzene per hour. Exhaust emission of a 2.9 kW, 2-stroke 
    lawnmower contains 17 grams of benzene per hour. A small, 2.2 kW 
    chainsaw emits 28.2 grams of benzene per hour, compared to a large, 4.5 
    kW chainsaw that emits 40.8 grams per hour.
        Also, according to data from the Nonroad Study, 1,3- butadiene 
    content in exhaust and crankcase emissions from a 2.9 kW, 4-stroke 
    lawnmower is approximately 1.5 grams per hour. For a 2.9 kW, 2-stroke 
    lawnmower, 1,3-butadiene content in exhaust is 7.0 grams per hour. 
    Butadiene emitted from a small, 2.2 kW chainsaw is approximately 12.2 
    grams per hour, and is 17.7 grams per hour from a large 4.5 kW 
    chainsaw.
        Benzene is a clear, colorless aromatic hydrocarbon which is both 
    volatile and flammable. Benzene is present in both exhaust and 
    evaporative emissions. Health effects caused by benzene emissions 
    differ based on concentration and duration of exposure.
        1,3-butadiene is a colorless, flammable gas at room temperature. 
    This suspected human carcinogen is insoluble in water and its two 
    conjugated double bonds make it highly reactive. 1,3-Butadiene is 
    formed in internal combustion engine exhaust by the incomplete 
    combustion of the fuel and is assumed not present in evaporative and 
    refueling emissions.
        Since air toxic levels generally decrease in proportion to overall 
    emissions once emission control technology is applied, the amount of 
    benzene and 1,3-butadiene produced by new small SI engines should 
    diminish after this rule becomes effective. Consequently, exposure to 
    air toxics from new small SI engines will be reduced, as will 
    associated health effects.
        There is little data on direct health effects of small SI engine 
    emissions. No study has been conducted involving the health effects of 
    air toxic emissions specifically from small SI engines. The Agency 
    requests additional information on this topic.
    
    C. Health and Welfare Effects of CO Emissions
    
        Carbon monoxide (CO) is a colorless, odorless gas which can be 
    emitted into ambient air as a result of both natural processes and 
    human activity. Although CO exists as a trace element in the 
    troposphere, much of human exposure resulting in elevated levels of 
    carboxyhemoglobin (COHb) in the blood is due to incomplete fossil fuel 
    combustion, as occurs in small SI engines.
        The concentration and direct health effect of CO exposure are 
    especially important in small SI engines because the operator of a 
    small SI engine application is typically near the equipment as it 
    functions. In some applications, the operator must be adjacent to the 
    exhaust outlet and is in the direct path of the exhaust as it leaves 
    the engine. According to numbers published in the Nonroad Study, a 4-
    stroke, 2.9 kW lawnmower engine emits 1051.1 g/hr CO, while a 2-stroke, 
    2.9 kW engine emits 1188.4 g/hr CO.
        Although no studies measuring the human health effects of CO 
    emanating from small SI engine exhaust have been conducted, ample 
    research results are available concerning general health effects of 
    exposure to CO. The toxicity of CO effects on blood and tissues, and 
    how these effects manifest themselves as organ function changes have 
    been topics of substantial research efforts. However, most of these 
    involved higher, more constant exposure concentration levels of CO than 
    are likely to be produced under normal operations of these small SI 
    engines. Such studies provided information for establishing the 
    National Ambient Air Quality Standard for CO. The current primary and 
    secondary NAAQS for CO are 9 parts per million for the one-hour average 
    and 35 parts per million for the eight-hour average.
    
    D. Roles of HC and NOX in Ozone Formation
    
        Both HC and NOX contribute to the formation of tropospheric 
    ozone through a complex series of reactions. In general, the ratio 
    between the ambient concentrations of HC and NOX in a localized 
    area is an indicator of the likely effectiveness of HC and/or NOX 
    reductions as ozone control measures. If the level of HC is high 
    relative to the level of NOX (that is, in a ratio of 20 to one), 
    ozone formation is limited by the amount of NOX present, making 
    reduction of NOX emission an effective strategy for reducing ozone 
    levels. Alternatively, if the level of HC is low relative to the level 
    of NOX (that is, in a ratio of eight to one), efforts to control 
    HC would be expected to be a more effective means of reducing ozone 
    concentration. In a recent report, researchers emphasize that both HC 
    and NOX controls are needed in most areas of the United 
    States.\10\
    ---------------------------------------------------------------------------
    
        \10\National Research Council, Rethinking the Ozone Problem in 
    Urban and Regional Air Pollution, National Academy Press, 1991.
    ---------------------------------------------------------------------------
    
    E. Health and Welfare Effects of Tropospheric Ozone
    
        EPA's primary reason for controlling emissions from small SI 
    engines is the role of HC in forming ozone. Of the major air pollutants 
    for which NAAQS have been designated under the CAA, the most widespread 
    problem continues to be ozone, which is the most prevalent 
    photochemical oxidant and an important component of smog. Ozone is a 
    product of the atmospheric chemical reactions involving oxides of 
    nitrogen and other compounds. These reactions occur as atmospheric 
    oxygen and sunlight interact with hydrocarbons and oxides of nitrogen 
    from both mobile and stationary sources.
        A critical part of this problem is the formation of ozone both in 
    and downwind of large urban areas. Under certain weather conditions, 
    the combination of NOX and HC can result in urban and rural areas 
    exceeding the national ambient ozone standard by a factor of three. The 
    ozone NAAQS represents the maximum level considered protective of 
    public health by the EPA.
        Ozone is a powerful oxidant causing lung damage and reduced 
    respiratory function after relatively short periods of exposure 
    (approximately one hour). The oxidizing effect of ozone can irritate 
    the nose, mouth, and throat causing coughing, choking, and eye 
    irritation. In addition, ozone can also impair lung function and 
    subsequently reduce the respiratory system's resistance to disease, 
    including bronchial infections such as pneumonia.
        Elevated ozone levels can also cause aggravation of pre-existing 
    respiratory conditions such as asthma.\11\ Ozone can cause a reduction 
    in performance during exercise even in healthy persons. In addition, 
    ozone can also cause alterations in pulmonary and extrapulmonary 
    (nervous system, blood, liver, endocrine) function.
    ---------------------------------------------------------------------------
    
        \11\United States Environmental Protection Agency, Review of the 
    National Ambient Air Quality Standards for Ozone--Assessment of 
    Scientific and Technical Information: OAQPS Staff Paper, EPA-450/2-
    92-001, June 1989, pp. VI-11 to 13.
    ---------------------------------------------------------------------------
    
        The current NAAQS for ozone of 0.12 part per million (ppm) is set 
    at a level that, with an adequate margin of safety, is protective of 
    public health. However, ozone has also been shown to damage forests and 
    crops, watershed areas, and marine life.\12\ The NAAQS for ozone is 
    frequently violated across large areas in the United States, and after 
    20 years of efforts aimed at reducing ozone-forming pollutants, 
    although EPA has reported a trend toward lower average ozone 
    concentrations from 1982 to 1989,\13\ the ozone standard has proven to 
    be exceptionally difficult to achieve. High levels of ozone have been 
    recorded even in relatively remote areas, since ozone and its 
    precursors can travel hundreds of miles and persist for several days in 
    the lower atmosphere. Ozone damage to plants, including both natural 
    forest ecosystems and crops, occurs at ozone levels between 0.06 and 
    0.12 ppm.\14\ Repeated exposure to ozone levels above 0.04 ppm can 
    cause reductions in the yields of some crops above ten percent.\15\ 
    While strains of some crops are relatively resistant to ozone, many 
    crops experience a loss in yield of 30 percent at ozone concentrations 
    below the NAAQS.\16\ The value of crops lost to ozone damage, while 
    difficult to estimate precisely, is on the order of $2 billion per year 
    in the United States.\17\ The effect of ozone on complex ecosystems 
    such as forests is even more difficult to quantify. However, there is 
    evidence that some forest types are negatively affected by ambient 
    levels of ozone.\18\ Specifically, in the San Bernadino Mountains of 
    southern California, ozone is believed to be the agent responsible for 
    the slow decline and death of ponderosa pine trees in these forests 
    since 1962.\19\
    ---------------------------------------------------------------------------
    
        \12\U.S. EPA, Review of NAAQS for Ozone.
        \13\NRC, Rethinking the Ozone Problem, p. 61.
        \14\U.S. EPA, Review of NAAQS for Ozone, p. X-10.
        \15\U.S. EPA, Review of NAAQS for Ozone, p. X-10.
        \16\U.S. EPA, Review of NAAQS for Ozone, p. X-10.
        \17\U.S. EPA, Review of NAAQS for Ozone, p. X-22.
        \18\U.S. EPA, Review of NAAQS for Ozone, p. X-27.
        \19\U.S. EPA, Review of NAAQS for Ozone. p. X-29.
    ---------------------------------------------------------------------------
    
        Finally, by trapping energy radiated from the earth, tropospheric 
    ozone may contribute to heating of the earth's surface, thereby 
    contributing to global warming (that is, the greenhouse effect,\20\ 
    although tropospheric ozone is also known to reduce levels of UVB 
    radiation reaching the earth's surface, the increase of which is 
    expected to result from depletion of stratospheric ozone.\21\
    ---------------------------------------------------------------------------
    
        \20\NRC, Rethinking the Ozone Problem, p. 22.
        \21\The New York Times, September 15, 1992, p. C4.
    ---------------------------------------------------------------------------
    
    VII. Technology Assessment
    
        In the draft RSD, EPA presents a comprehensive technology 
    assessment supporting the emission standards proposed for each class of 
    engines in this notice. This assessment demonstrates that small SI 
    engine manufacturers will be technically capable of achieving the 
    proposed emission standards and will not be capable of achieving lower 
    emission standards in this Phase 1 rule. This assessment also considers 
    factors of noise, energy, and safety as outlined in section 213(a)(3) 
    of the CAA. The public docket for this rulemaking contains a lengthier 
    version of this Technology Assessment section.
        The levels of the proposed emission standards under this rule are 
    in large part driven by the aggressive timeline of Phase 1. EPA agreed 
    to promulgate Phase 1 small SI engine standards to realize early 
    emission reduction benefits while a more comprehensive long-term 
    program will be developed for Phase 2.
    
    A. Achievability of Proposed Emission Standards
    
        EPA believes that the proposed Phase l emission standards are the 
    lowest standards for Class I-V engines achievable by the 1996 model 
    year.
        The engines covered by this proposed regulation are divided into 
    five classes with unique emission standards proposed for each class. 
    The lowest level of emission standards achievable was determined for 
    each class of engines. The unique standards for each class are driven 
    by differences in emission reduction capability of engines with 
    different combustion cycles and different displacements.
        Class I and II engines represent nonhandheld engines that, in large 
    part, use 4-stroke combustion cycle engines, as opposed to Class III-V 
    engines which represent handheld engines that, in large part, use 2-
    stroke combustion cycle engines. Within the time constraints for 
    compliance with this rule, Class I and II engines will be capable of 
    achieving a lower HC + NOX composite emission standard and lower 
    CO emission standard than the Class III-V engines are capable of 
    achieving. Furthermore, within each combustion cycle type, the larger 
    displacement classes will be capable of achieving lower HC + NOX, 
    HC, and CO emission standards. A full discussion of the technical 
    rationale for these limitations is set forth in the draft RSD.
        EPA's belief that the proposed emission standards for Classes I-V 
    are the lowest achievable standards is based on emission data provided 
    on nonoptimized prototype configurations of engines that meet the 
    proposed standards, technical discussions with manufacturers, and EPA 
    analysis of information on technologies collected from a range of 
    sources. The following is a summary of these analyses. A complete 
    analysis is provided in the draft RSD.
        EPA has compiled emission data on selected Class I-V engines and 
    prototypes that were tested at either an independent or industry 
    laboratory and met the proposed emission standards. These prototypes 
    represent the greatest degree of emission control technology achievable 
    given the aggressive timeline for earliest possible introduction of 
    these engines into commerce at reasonable cost (one of the parameters 
    for achievability listed in CAA section 213(a)(3)). Data was compiled 
    and reported on three Class I engines, two Class II engines, one Class 
    III engine, two Class IV engines plus one data point representing the 
    aggregate of 27 Class IV engines, and one Class V engine plus one data 
    point representing the aggregate of 18 Class V engines. These data and 
    the specific technologies used on each are presented in Chapter 1 of 
    the draft RSD.
        Additional support for the proposed emission standards being the 
    lowest achievable standards is provided by EPA's analytical summary of 
    confidential discussions with manufacturers and information on 
    technologies collected from a range of sources. EPA used this summary 
    information to compile and predict the expected percentage usage of 
    each emission control technology discussed.
        For Class I and II engines, EPA predicts that manufacturers will 
    use different combinations of the following technologies: Carburetor 
    enleanment and/or modifications; fuel system modifications; ignition 
    timing modifications; valve system and valve timing modifications; 
    combustion chamber modifications; cooling system modifications; some 
    conversion from side valve to overhead valve engines; and some 
    conversion from 2-stroke to 4- stroke engines.
        For Class III, IV, and V engines, EPA predicts that manufacturers 
    will use combinations of the following technologies: Carburetor 
    enleanment and/or modifications; carburetor limiter cap installation; 
    fuel system modifications; combustion chamber modifications; port 
    timing and scavenging modifications; cooling system modifications; and 
    some conversion from 2-stroke to 4-stroke engines. The estimated 
    percent usage of each technology by engine class is presented and 
    discussed in the draft RSD.
        In addition to the technologies listed, the use of catalytic 
    converters, exhaust gas recirculation (EGR), and air injection 
    technology may occur on a limited basis or not at all in the 1996 model 
    year. EPA estimates that manufacturers will meet proposed Phase 1 
    emission standards without the use of catalysts. However, some 
    manufacturers are developing low efficiency catalysts in case some 
    marginally acceptable engine family should need this technology to meet 
    the standards. If catalysts were to be used, EPA estimates that their 
    use would occur on no more than 30 percent of Class I engines and one 
    percent of all Class II-V engines. EPA requests information on the 
    likelihood that catalyst, EGR, or air injection systems will be used 
    and, if so, any additional information on percent usage.
    
    B. Proposed Emission Standards Are Lowest Feasible
    
        EPA believes that three specific emission control technologies, 
    while allowing engines to meet lower standards than those proposed 
    today, cannot be developed within the timeline of this rule or at 
    reasonable cost. Technologies such as high efficiency catalytic 
    converters, low cost fuel injection systems, and low cost electronic 
    control systems are currently either available on only a limited basis 
    or are in the early design phase. These technologies cannot be used on 
    the vast majority of engines by the proposed implementation date. These 
    technologies have the potential to develop much greater emission 
    reductions than those technologies determined to be achievable for this 
    rule. As discussed in Chapter 1 of the draft RSD, a number of technical 
    barriers and safety issues must still be overcome before standards can 
    be set that would reflect general or blanket use of these technologies.
    
    C. Impact on Equipment
    
        EPA estimates that the proposed emission standards can be met with 
    the identified engine emission control technologies with minimal impact 
    on equipment design. However, EPA also believes that to propose more 
    stringent emission standards in today's rule than those already 
    proposed would necessitate equipment redesign to accommodate more 
    sophisticated technologies, such as high efficiency catalysts.
        It has been EPA's past experience that, given the latitude to 
    change either the engine or equipment, most manufacturers will choose 
    to modify the engine. EPA estimates that most engine models will 
    require only internal modifications (such as tighter tolerances and 
    fuel mixture enleanment strategies) to meet the proposed standards. 
    These modifications will have little, if any, effect on equipment 
    design.
        EPA estimates that few engine models will be discontinued as a 
    result of the proposed standards. Models that may be discontinued 
    represent older engine designs and low volume sales. Since this market 
    generally has a large number of engine models, substitutions should be 
    readily available for these few incidents of model discontinuation.
        Catalytic converter use is not predicted for the Phase 1 rule. 
    However, if catalysts should be used on a small percentage of 
    equipment, EPA has estimated the equipment impact of catalyst use in 
    terms of additional shielding as a result of higher exhaust skin 
    temperatures.
        The draft RSD summarizes EPA's estimates of equipment impacts as a 
    result of this rulemaking. EPA requests comment or additional 
    information with respect to the estimations concerning impact of the 
    proposed standards on equipment.
    
    D. Energy, Noise, and Safety
    
        Section 213(a)(3) of the Act requires that EPA also give 
    appropriate consideration to energy, noise, and safety factors 
    associated with the application of technologies. Energy factors include 
    engine fuel consumption and power. Noise factors are self explanatory, 
    and safety factors include safety for the user as well as compliance 
    with other existing regulations in this country and abroad.
        In Chapter 1 of the draft RSD, EPA has analyzed the likely average 
    fuel consumption change considering all factors that would impact the 
    final figure in actual use. EPA estimates that a reduction in fuel 
    consumption is likely to be seen in actual use and will average 
    approximately 13 percent for handheld engines and 26 percent for 
    nonhandheld engines. Since this is a desirable impact, little 
    additional design effort will be expended to optimize fuel consumption 
    effects.
        Manufacturers will also optimize final designs such that the 
    expected power loss on resulting production engines will be minimized. 
    Based on analyses in Chapter 1 of the draft RSD, EPA estimates that the 
    resulting average power change in actual use will be a gain of 
    approximately five percent for Class I and II engines and a three 
    percent reduction for Class III-V engines. The major contributors to 
    this gain for Class I and II are changes in technology for Class I side 
    valve engines which make up a large majority of engines in this 
    rulemaking.
        Although overall power may increase, some engines may experience a 
    decrease in power availability. However, real time data collected on 
    equipment in actual use demonstrate that many engines do not need their 
    full power capability in actual use. This is especially true in the 
    case of nonhandheld engines. The operators of these engines will likely 
    experience no performance impact as a result of this rule.
        Engine noise level is expected to stay at current levels. Further 
    discussion of this issue can be found in ``V.O. Cap on Noise.''
        Many safety regulations and recommendations have been established 
    for small engines and their related use in equipment. These regulations 
    will affect the feasibility of using some technologies on handheld 
    engines. One example is a regulation requiring spark arresters on 
    equipment used on certain federal lands. See 36 CFR part 261. The 
    regulation results in a temperature limit on exhaust and exhaust 
    surfaces which, to date, has resulted in a limitation on the 
    feasibility of the use of catalysts for handheld engines due to the 
    high heat levels emitted during conversion of pollutants as seen when 
    applied to these engines.
        Safety recommendations and regulations also have an impact on the 
    end use of the engines. Some small SI equipment have operating 
    restrictions of certain speeds and loads. One example is ANSI standard 
    B71.1 which contains information for measuring mower blade tip speed 
    and a description of the use of safety brake systems. A summary of 
    safety regulations and recommendations is presented in the draft RSD. 
    EPA requests further information on additional safety regulations or 
    requirements which may impact engines covered by this rulemaking.
    
    E. Per Engine Cost Estimates Due to Proposed Standards
    
        The technical solutions required to meet the emission standards 
    proposed in this notice will be cost-effective. Further discussion is 
    presented in ``IX. Cost-Effectiveness.'' While this summary presents 
    only aggregate costs for nonhandheld and handheld engines, the draft 
    RSD gives cost estimates by technology and by engine displacement 
    class.
        The retail price of equipment which uses nonhandheld engines ranges 
    from $90 to $9,000. On average, the cost to the engine manufacturer to 
    install the necessary emission control technology on these engines will 
    be approximately $0.80 to $1.13 per engine. The retail price of 
    equipment which uses handheld engines ranges from $60 to $1,000. On 
    average, the cost to install the necessary control technology on all 
    handheld equipment engines, hardware variable costs, and production 
    costs will be approximately $2.05 to $2.20 per engine to the engine 
    manufacturer. Tables in the draft RSD list the Agency's estimated 
    variable hardware and production cost broken out by engine technology 
    for each engine class.
        EPA's cost estimate assumes that catalytic converters will not be 
    needed to comply with proposed standards. However, as discussed 
    previously, engine manufacturers may voluntarily decide to use 
    catalysts on a percentage of engines at risk of only marginally 
    complying. Should catalysts actually be used, EPA estimates that the 
    additional variable hardware costs for nonhandheld engines will be 
    $1.09 per engine and for handheld engine will be $0.10 per engine, with 
    an additional $0.24 per engine for equipment modifications and $0.20 
    per potential heat shielding. The Agency requests additional comment on 
    these cost estimates for application of catalyst technology and 
    equipment impacts.
    
    VIII. Economic Effects
    
        The total national average annual cost of this rule is estimated to 
    be $55 million. If catalysts become necessary, the average annual cost 
    estimate becomes $73 million.
        EPA's economic analysis of the proposed rule's likely impact on 
    consumers and industry indicates that reducing pollution from these 
    engines will result in offsetting costs to consumers. Consumers will 
    find small increases in retail prices for most equipment powered by 
    these engines. The initial purchase price to the consumer will, 
    however, be partially offset by savings in fuel and maintenance costs. 
    Thus, over time, environmentally friendly, alternatively powered 
    equipment such as electric powered trimmers, chain saws, and lawnmowers 
    will become less costly to consumers. Industry will bear pollution 
    control costs that are moderate (roughly six percent for handheld and 
    two percent for nonhandheld equipment) relative to current production 
    costs. (The level of pollution control costs is largely due to the high 
    levels of pollution emitted by these engines, especially 2-stroke 
    engines, and the relatively outdated state of the technology compared 
    to on-highway engines.) However, the costs are small in absolute terms, 
    and it is anticipated that these costs will be passed through to 
    consumers in higher product prices. The complete economic analysis can 
    be found in Chapter 3 of the draft RSD.
    
    A. Consumer Cost
    
        EPA estimated the increase in consumer cost of the equipment 
    powered by these engines. In assessing consumer cost, three areas were 
    analyzed: change to the retail cost of the engine, cost of fuel, and 
    cost of maintenance.
    1. Retail Cost
        The increase in retail price of the equipment to the consumer is 
    estimated using a percentage increase over the average amortized and 
    discounted per engine manufacturers' cost, weighted by the sales mix. 
    As such, the estimated sales-weighted average increase in retail cost 
    to the consumer due to the proposed rule in 1996 is $4.04 for handheld 
    equipment and $2.35 for nonhandheld equipment. If catalysts are 
    necessary, the estimated sales-weighted average increase in retail cost 
    to the consumer due to the proposed rule in 1996 is $4.30 for handheld 
    equipment and $3.68 for nonhandheld equipment.
        The retail price effects for specific engines may be more or less 
    than the costs shown here, depending on the specific technology of the 
    engine. However, the price increases shown here reflect the relative 
    price increases considering all types of engines in the market. 
    Therefore, these estimates are not indicative of the price increase 
    specific to any particular manufacturer's engine or equipment.
    2. Fuel Cost
        This rule is expected to decrease fuel consumption significantly. 
    The average sales-weighted handheld engine is expected to experience a 
    13 percent decrease in fuel consumption and the average sales-weighted 
    nonhandheld engine is expected to experience a 26 percent decrease in 
    fuel consumption. However, these decreases are translated into small 
    discounted lifetime sales-weighted fuel savings of approximately $0.22 
    for a handheld engine and $2.79 for a nonhandheld engine.
    3. Maintenance Cost
        EPA estimates that the engines produced to meet the proposed 
    emission standards will be higher quality: the parts and raw materials 
    will be more durable and less likely to malfunction. See Chapter 2 of 
    the draft RSD for further discussion of this phenomenon. This will 
    result in equipment which is operational a higher percentage of the 
    time and which lasts longer. EPA is unable to estimate the increase in 
    useful life or the decrease in maintenance costs at this time. EPA 
    requests comment on the potential decrease in maintenance costs and 
    potential increase in useful life.
    4. Lifetime Consumer Cost Impact
        The lifetime consumer cost impact was assessed by considering the 
    decrease in maintenance cost and the fuel savings along with the 
    increase in retail price of the average, sales- weighted engine. The 
    increase in price of an engine will be mitigated somewhat by these 
    other impacts. Applying the lifetime savings in fuel costs, the average 
    sales-weighted handheld engine's lifetime increase in cost will be 
    adjusted to $3.82 and the average sales-weighted nonhandheld engine's 
    lifetime cost impact will be a savings of $0.44. If catalysts are 
    necessary this will be $4.08 for a handheld engine and $.89 for a 
    nonhandheld engine. EPA requests comments on lifetime consumer costs. 
    Submission of quantified estimates would be beneficial.
    
    B. Incremental Economic Impacts
    
        EPA considered the potential incremental economic impacts due to 
    today's proposal. EPA estimates the net present value of pollution 
    control capital costs to be approximately $27 million. EPA estimates 
    that there will be no long run negative impacts on employment as a 
    result of this rule. Costs can be recovered through increased prices. 
    Any potential decreases in employment that might occur due to 
    obsolescence of product line should be offset by increased production 
    of engines meeting emission standards. Total demand for these products 
    has traditionally been relatively inelastic, and thus industry sales 
    volume is not expected to decrease. Energy impacts will be positive, 
    freeing up approximately $9 million for other uses in the economy.
    
    IX. Cost-Effectiveness
    
        Based upon the costs and benefits in the previous discussion, EPA 
    has prepared a cost-effectiveness analysis and has performed a 
    Regulatory Impact Analysis (RIA) for this proposal. See ``X.A. 
    Administrative Requirements'' for an explanation of the mandate for an 
    RIA. Because the benefits of this proposal are not easily monetized, a 
    cost-effectiveness analysis has been prepared. The complete RIA is 
    contained in the draft RSD. Presented here is a summary of the cost-
    effectiveness of the proposed small SI engine Phase 1 program.
        If all program costs are allocated to HC reductions, today's 
    proposal has a cost-effectiveness of $197 per ton of HC reduced. 
    Alternatively, if all program costs are allocated to CO reductions, the 
    cost-effectiveness would be $37 per ton.
        If the costs of the program were equally split between HC and CO, 
    the cost-effectiveness of HC reduction would be $99 per ton and the 
    cost-effectiveness of CO would be $19 per ton.
        These cost-effectiveness numbers are significantly lower than costs 
    per ton of other available control strategies. The cost-effectiveness 
    estimates, underlying quantitative methodology, and comparisons to 
    other available control strategies discussed above are explained 
    further in the draft RSD/RIA.
        In summary, the cost-effectiveness of the standard included in the 
    current proposal is favorable relative to the cost- effectiveness of 
    several other control measures required under the Clean Air Act. To the 
    extent that cost-effective nationwide controls are applied to small SI 
    engines, the need may be reduced to apply in the future more expensive 
    additional controls to mobile and stationary sources that also 
    contribute to ozone nonattainment, nutrient loading, and visibility.
    
    X. Administrative Requirements
    
    A. Administrative Designation and Regulatory Analysis
    
        Under Executive Order 12866, (58 Federal Register 51,735 (October 
    4, 1993)) the Agency must determine whether the regulatory action is 
    ``significant'' and therefore subject to OMB review and the 
    requirements of the Executive Order. The order defines ``significant 
    regulatory action'' as one that is likely to result in a rule that may: 
    (1) Have an annual effect on the economy of $100 million or more or 
    adversely affect in a material way the economy, a sector of the 
    economy, productivity, competition, jobs, the environment, public 
    health or safety, or State, local, or tribal governments or 
    communities; (2) create a serious inconsistency or otherwise interfere 
    with an action taken or planned by another agency; (3) materially alter 
    the budgetary impact of entitlement, grants, user fees, or loan 
    programs or the rights and obligations of recipients thereof; (4) raise 
    novel legal or policy issues arising out of legal mandates, the 
    President's priorities, or the principles set forth in the Executive 
    Order.
        Pursuant to the terms of Executive Order 12866, it has been 
    determined that this rule is a ``significant regulatory action'' 
    because this rulemaking adversely affects in a material way a sector of 
    the economy, namely manufacturers of small SI engines, particularly the 
    manufacturers who specialize in the production of small handheld 
    engines. Further, EPA believes that an RIA is important for this rule 
    because small SI engines have not previously been regulated. As such, 
    this action was submitted to OMB for review. Changes made in response 
    to OMB suggestions or recommendations will be documented in the public 
    record.
    
    B. Paperwork Reduction Act
    
        The information collection requirements in this proposed rule have 
    been submitted for approval to the Office of Management and Budget 
    (OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. Copies 
    of the ICR document may be obtained from Sandy Farmer, Information 
    Policy Branch, EPA, 401 M Street, SW (PM-223Y), Washington, DC 20460 or 
    by calling (202) 260-2740.
        Table 4 provides a listing of this proposed rulemaking's 
    information collection requirements along with the appropriate 
    information collection request (ICR) numbers. The cost of this burden 
    has been incorporated into the cost estimate for this rule.
        EPA has estimated that the public reporting burden for the 
    collection of information required under this proposed rule would 
    average approximately 6,100 hours annually for a typical engine 
    manufacturer. The hours spent by a manufacturer on information 
    collection activities in any given year would be highly dependent upon 
    manufacturer specific variables, such as the number of engine families, 
    production changes, emission defects, etc. 
    
                        Table 4. Public Reporting Burden                    
    ------------------------------------------------------------------------
      EPA ICR                                                    OMB control
       No.                    Type of information                    No.    
    ------------------------------------------------------------------------
    N/A         Certification..................................    2060-0104
    0282        Emission defect information....................    2060-0048
    N/A         Importation of nonconforming engines...........          N/A
    N/A         Selective enforcement auditing.................          N/A
    0012        Engine exclusion determination.................    2060-0124
    0095.03     Precertification and testing exemption.........    2060-0007
    N/A         In-use testing.................................         N/A 
    ------------------------------------------------------------------------
    
        Send comments regarding the burden estimate or any other aspect of 
    this collection of information, including suggestions for reducing this 
    burden to Chief, Information Policy Branch, EPA, 401 M Street, SW (PM-
    223Y), Washington, DC 20460; and to the Office of Information and 
    Regulatory Affairs, Office of Management and Budget, Washington, DC 
    20503, marked ``Attention: Desk Officer for EPA.'' The final rule will 
    contain response to OMB or public comments on the information 
    collection requirements contained in this proposal.
    
    C. Impact on Small Entities
    
        The Regulatory Flexibility Act of 1980 requires federal agencies to 
    identify potentially adverse impacts of federal regulations upon small 
    entities. In instances where significant impacts are possible on a 
    substantial number of these entities, agencies are required to perform 
    a Regulatory Flexibility Analysis (RFA). The RFA explores options for 
    minimizing those impacts.
        EPA has recently adopted a new approach to regulatory 
    flexibility\22\ for purposes of EPA's implementation of the Act, any 
    impact is a significant impact, and any number of small entities is a 
    substantial number. Thus, EPA will consider regulatory options for 
    every regulation subject to the Act that can reasonably be expected to 
    have an impact on small entities.
    ---------------------------------------------------------------------------
    
        \22\Habiicht, F. Henry II, Deputy Administrator, Internal EPA 
    Memorandum, ``Revised Guidelines for Implementing the Regulatory 
    Flexibility Act,'' April 9, 1992.
    ---------------------------------------------------------------------------
    
        Therefore, in light of this new approach, EPA has determined that 
    this rule will have a significant effect on a substantial number of 
    small entities. As a result, EPA has tailored this rule to minimize the 
    cost burdens imposed on smaller engine manufacturers.
        The proposed regulations contain certification requirements for new 
    engines, in-use testing requirements for controlled engines, Selective 
    Enforcement Auditing provisions for the testing of production engines, 
    and prohibitions on incorrect engine use for equipment manufacturers.
        The certification program has been structured in this proposal such 
    that all manufacturers may take advantage of a more simplified 
    certification process than that currently mandated in the on-highway 
    program. Testing requirements for test engines are reduced. The 
    application and certification process is more straightforward.
        The in-use testing program is structured such that manufacturers 
    with lower annual production volumes have a lower minimum number of 
    engines which must be tested. This places the burden of the in-use 
    testing mostly on manufacturers with high production volumes. 
    Provisions are also allowed for manufacturers whose number of product 
    lines are limited. Also, manufacturers with very low production volumes 
    are allowed maximum flexibility in procuring engines to be tested. 
    Refer to ``IV.C.10. In-use Testing Program'' for a more detailed 
    discussion.
        The SEA program is structured such that the annual limit on the 
    number of SEA's that EPA may perform is lower for manufacturers with 
    lower projected annual production. Additionally, manufacturers with 
    high projected annual production but fewer engine families will have a 
    lower annual limit. Furthermore, manufacturers with low projected 
    annual production may perform fewer audit tests per day to minimize the 
    SEA burden on its test facilities. Refer to ``IV.C.19. Selective 
    Enforcement Auditing Program'' for a more detailed discussion.
        EPA is proposing that equipment manufacturers must correctly use 
    engines that are certified upon implementation of these regulations. 
    However, EPA has decided to make the use of non- certified engines for 
    United States-marketed equipment a prohibited act rather than requiring 
    equipment manufacturers to report to EPA that they are using certified 
    engines in their equipment being consumed in the United States. 
    Further, it is a prohibited act for equipment manufacturers to 
    incorrectly use an engine certified as handheld in nonhandheld 
    equipment marketed in the United States. EPA decided to make these 
    provisions prohibited acts in order to reduce any potential reporting 
    or recordkeeping burden for engine and equipment manufacturers. 
    Manufacturers who attempt to sell equipment to the United States market 
    which uses noncertified engines or uses handheld engines in nonhandheld 
    equipment will be voluntarily reported to EPA by their competitors. EPA 
    has proposed stiff fines on prohibited acts. Competition should 
    effectively police these prohibited acts as competitors have a 
    competitive incentive to make sure that no equipment manufacturer is 
    dumping equipment with lower cost, unlawful, noncertified, or 
    incorrectly used engines (that is, the use of a handheld engine in 
    nonhandheld equipment) into the U.S. market.
        EPA considered, but rejected, the notion of exempting small 
    manufacturers from enforcement programs or from the regulation 
    entirely. A more proportionate sharing of cost burden was deemed 
    appropriate. The pollution emitted by each of these engines not only 
    contributes to ambient air quality problems but also has health impacts 
    on the user of the equipment who is in close proximity to the exhaust 
    emissions. See ``VI. Environmental Benefit Assessment'' for a 
    discussion of the health impacts of the related exhaust pollutants.
    
    List of Subjects in 40 CFR Part 90
    
        Environmental protection, Administrative practice and procedure, 
    Air pollution control, Confidential business information, Environmental 
    protection, Imports, Incorporation by reference, Labeling, Nonroad 
    source pollution, Reporting and recordkeeping requirements.
    
        Dated: April 29, 1994.
    Carol M. Browner,
    Administrator.
    [FR Doc. 94-10975 Filed 5-13-94; 8:45 am]
    BILLING CODE 6560-50-P
    
    
    

Document Information

Published:
05/16/1994
Department:
Environmental Protection Agency
Entry Type:
Uncategorized Document
Action:
Notice of proposed rulemaking.
Document Number:
94-10975
Dates:
Comments must be received on or before July 15, 1994. A public hearing will be held on June 21, at 10 a.m.; requests to present oral testimony must be received on or before June 15, 1994.
Pages:
0-0 (1 pages)
Docket Numbers:
Federal Register: May 16, 1994, FRL-4881-5
RINs:
2060 AE29
CFR: (1)
40 CFR 90