95-21525. Control of Air Pollution From Heavy-Duty Engines  

  • [Federal Register Volume 60, Number 169 (Thursday, August 31, 1995)]
    [Proposed Rules]
    [Pages 45580-45604]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 95-21525]
    
    
    
    
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    Part IV
    
    
    
    
    
    Environmental Protection Agency
    
    
    
    
    
    _______________________________________________________________________
    
    
    
    40 CFR Parts 80, 86, and 89
    
    
    
    Control of Air Pollution From Heavy-Duty Engines; Proposed Rule
    
    Federal Register / Vol. 60, No. 169 / Thursday, August 31, 1995 / 
    Proposed Rules 
    
    [[Page 45580]]
    
    
    ENVIRONMENTAL PROTECTION AGENCY
    
    40 CFR Parts 80, 86, and 89
    
    [AMS-FRL-5288-4]
    RIN 2060-AF76
    
    
    Control of Air Pollution From Heavy-Duty Engines
    
    AGENCY: Environmental Protection Agency.
    
    ACTION: Advance notice of proposed rule.
    
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    SUMMARY: This advance notice of proposed rule (ANPRM) reviews the need 
    and potential for additional reductions in emissions of oxides of 
    nitrogen (NOX), hydrocarbons (HC), and particulate matter (PM) 
    from mobile source heavy-duty engines (HDEs), announces EPA's intent to 
    establish new emission controls for highway heavy-duty engines, and 
    also describes EPA's plans to work cooperatively with engine and 
    equipment manufacturers to consider additional reductions from nonroad 
    (off-highway) heavy-duty engines. Ozone pollution poses a serious 
    threat to the health and well-being of millions of Americans and a 
    large burden to the U.S. economy. Many ozone nonattainment areas face 
    great difficulties in reaching and maintaining attainment of the ozone 
    health-based air quality standards in the years ahead. Recognizing this 
    challenge, states, local governments and others have called on EPA to 
    promulgate additional national measures to reduce NOX and HC in 
    order to protect the public from the serious health effects of ozone 
    pollution. The control of PM emissions from HDEs is also a priority for 
    these stakeholders.
        In response to the need for national pollution reduction measures, 
    EPA has initiated discussions with engine manufacturers regarding 
    future emission controls for HDEs. EPA, the California Air Resources 
    Board (CARB), and HDE manufacturers recently signed a Statement of 
    Principles (SOP) calling for significantly tighter NOX and non-
    methane hydrocarbon (NMHC) standards for on-highway HDEs starting with 
    model year 2004. The SOP calls on manufacturers to achieve these ozone 
    precursor reductions without increasing PM emissions, even though 
    current diesel technology typically results in increased PM (and HC) 
    emissions when NOX emissions are reduced. The parties plan to 
    continue their discussions and to invite others to join them, with a 
    goal of reaching a similar SOP for nonroad HDEs.
    DATES: EPA requests comment on this ANPRM no later than October 2, 
    1995. Should a commenter miss the requested deadline, EPA will try to 
    consider any comments that it receives prior to publication of the 
    expected NPRM regarding additional highway heavy-duty engine emission 
    controls. There will also be an opportunity to comment on any NPRM that 
    EPA publishes.
    
    ADDRESSES: Materials relevant to this ANPRM are contained in Public 
    Docket A-95-27, located at room M-1500, Waterside Mall (ground floor), 
    U.S. Environmental Protection Agency, 401 M Street SW., Washington, DC 
    20460. The docket may be inspected from 8 a.m. until 5:30 p.m., Monday 
    through Friday. A reasonable fee may be charged by EPA for copying 
    docket materials.
    
        Comments on this ANPRM should be sent to Public Docket A-95-27 at 
    the above address. EPA requests that a copy of comments also be sent to 
    Tad Wysor, U.S. EPA, Regulation Development and Support Division, 2565 
    Plymouth Road, Ann Arbor, MI 48105.
    
        This ANPRM is available electronically on the Technology Transfer 
    Network (TTN), which is an electronic bulletin board system (BBS) 
    operated by EPA's Office of Air Quality Planning and Standards. The 
    service is free of charge, except for the cost of the phone call. Users 
    are able to access and download TTN files on their first call using a 
    personal computer and modem: TTN BBS, (919) 541-5742; Voice Helpline, 
    (919) 541-5384.
    
    FOR FURTHER INFORMATION CONTACT: Tad Wysor, U.S. EPA, Regulation 
    Development and Support Division, 2565 Plymouth Road, Ann Arbor, MI 
    48105. Telephone: (313) 668-4332.
    
    SUPPLEMENTARY INFORMATION: EPA is issuing this ANPRM to invite 
    comment from all interested parties on the need and potential for 
    additional reduction of NOX, HC and PM emissions from HDEs and 
    EPA's plans to achieve such reductions. After reviewing the 
    comments, EPA intends to issue a Notice of Proposed Rulemaking 
    (NPRM) proposing standards for Model Year 2004 and later heavy-duty 
    highway engines in accordance with the SOP. In addition, comments 
    received regarding reduction in emissions from nonroad HDEs will 
    inform any EPA discussions with manufacturers regarding additional 
    emission reductions.
    
    I. Introduction
    
        Poor air quality represents a serious threat to the health and 
    well-being of millions of Americans and a large burden to the U.S. 
    economy. This threat exists despite the fact that, over the past two 
    decades, great progress has been made at the local, state and national 
    levels in controlling emissions from many sources of air pollution. As 
    a result of this progress, many individual emission sources, both 
    stationary and mobile, pollute at only a fraction of their pre-control 
    rates. However, continued industrial growth and expansion of motor 
    vehicle usage threaten to reverse these past achievements. Today, more 
    than four years after the passage of major amendments to the Clean Air 
    Act (CAA or Act),1 many states are still finding it difficult to 
    meet the air quality standards by the CAA deadlines. Furthermore, other 
    states which are approaching or have reached attainment of National 
    Ambient Air Quality Standards (NAAQS) may see those gains lost if 
    current trends persist.
    
        \1\ See 42 U.S.C. 7401 et seq.
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        In recent years, efforts to improve air quality have focused 
    largely on ground-level ozone and its main precursors, nitrogen oxides 
    (NOX) and volatile organic compounds (VOCs, consisting mostly of 
    hydrocarbons, HC). In addition, airborne particulate matter (PM) has 
    been a major air quality concern in many regions. As discussed below, 
    NOX, ozone, and PM have all been linked to a range of serious 
    respiratory health problems and a variety of adverse environmental 
    effects.
        At this time, ozone levels remain unacceptably high in many areas 
    across the country. For many years, control of VOCs was the main 
    strategy employed in efforts to reduce ground-level ozone. VOC 
    reductions were more cost effective (on a per-ton basis) and more 
    readily achievable than NOX reductions. In addition, it was 
    generally believed that greater ozone benefits could be achieved 
    through VOC reductions. More recently, it has become clear that 
    NOX controls are often the most effective strategy for reducing 
    ozone, especially where ozone is high over a large region (as in the 
    Midwest and Northeast). As a result, attention has turned to NOX 
    emissions as the key to improving air quality in many areas of the 
    country.
        Current projections show a slight decrease in total NOX 
    emissions during the next few years as stationary and mobile source 
    control programs promulgated under the 1990 CAA are phased in. However, 
    downward trends in NOX pollution will begin to reverse and 
    NOX emission inventories begin to rise by the early 2000s, due to 
    growth in stationary and mobile source activity, and emissions from 
    heavy-duty highway and nonroad engines are projected to represent a 
    significant fraction of mobile 
    
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    source NOX emissions by the middle of the next decade. In some 
    areas, the rise in NOX emissions can be expected to be accompanied 
    by a significant increase in ground-level ozone. Levels of PM are also 
    expected to rise, both because of the expected increase in numbers of 
    PM sources and because in the atmosphere, NOX is transformed into 
    fine acidic nitrate particles which account for a substantial fraction 
    of the airborne particulate in some areas of the country (``secondary 
    particulate formation'').
        Given these expected trends, and in the absence of new emission 
    control initiatives, some of the nation's hard-won air quality 
    improvements will begin to be seriously threatened in the early 2000s. 
    In response to widespread urging by states, municipalities, health 
    officials, and concerned citizens in virtually every region of the 
    country,2 EPA has intensified its efforts to understand and 
    respond to today's stubborn air quality challenges. Over the past 
    decade, ambient air measurements and computer modeling studies have 
    repeatedly demonstrated that ozone and its precursors, NOX and 
    VOC, are transported across large distances. Thus, while there is a 
    role for all levels of government to address these issues, EPA's state 
    and local partners generally agree that only with new initiatives at 
    the regional and national level can long-term clean air goals be 
    achieved.
    
        \2\ See Section VI for more detailed discussion of the comments 
    received by EPA to date.
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        States are assigned the jurisdiction by the CAA for implementing 
    most stationary source emission controls. In most regions of the 
    country, states are implementing stationary source NOX control 
    options (as well as stationary source VOC controls) for the control of 
    acid rain, ozone, or both. However, in many areas these controls will 
    not be sufficient for reaching and/or maintaining the ozone standard 
    without significant additional NOX reductions from mobile sources. 
    California can establish emission control standards for new motor 
    vehicles, and other states may adopt California's programs.3 
    Traditionally, however, nationwide VOC and NOX control programs 
    for new motor vehicles are initiated at the federal level. Similarly, 
    mobile sources of PM emissions, especially the direct and indirect PM 
    from diesel engines, are a major consideration to local and state 
    officials in areas facing current and future air quality problems. 
    Thus, those charged with delivering cleaner air to the citizens of 
    their states are looking to the national mobile source emission control 
    program as a necessary complement to their efforts to reduce NOX, 
    PM, HC, and other emissions. Common emission standards for mobile 
    sources across the nation are also strongly supported by manufacturers, 
    which often face serious production inefficiencies when different 
    requirements apply to engines/vehicles sold in different states or 
    areas.
    
        \3\ A similar relationship applies to new nonroad engines and 
    vehicles, although states may not set standards for certain classes 
    of these engines and vehicles. See Sections 209 and 213 of the Act.
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        Motor vehicle emission control programs have a history of 
    technological success that, in the past, has largely offset the 
    pressure from constantly growing numbers of vehicles and miles traveled 
    in the U.S. The per-vehicle rate of emissions from new passenger cars 
    and light trucks has been reduced to very low levels. As a result, 
    increasing attention is now being focused on heavy-duty trucks (ranging 
    from large pickups to tractor-trailers), buses, and nonroad equipment. 
    For purposes of this ANPRM, the Agency is primarily interested in the 
    component of nonroad sources greater than 50 horsepower (37 kilowatts), 
    which is termed ``heavy-duty nonroad'' in this Notice. (Nonroad engines 
    greater than 50 hp represent the single largest contributor to total 
    nonroad NOX emissions.) EPA is addressing other off-highway 
    sources, such as small nonroad engines, locomotives, aircraft and 
    marine engines in separate actions.
        Since the 1970s, manufacturers of heavy-duty engines for highway 
    use have developed new technological approaches in response to 
    increasingly stringent emission standards. However, the technological 
    characteristics of heavy-duty engines, particularly diesel engines, 
    have to date prevented the achievement of emission levels comparable to 
    today's light-duty gasoline vehicles. While diesel engines provide 
    advantages in terms of fuel efficiency, reliability, and durability, 
    control of NOX emissions is a much greater challenge for diesel 
    engines than for gasoline engines. Similarly, control of PM emissions, 
    which are at very low levels for gasoline engines, represents a 
    substantial challenge for diesel engines.
        Despite these technological challenges, there is emerging agreement 
    that heavy-duty highway engines offer the potential for substantial 
    additional emission reductions. In their successful efforts to reach 
    lower NOX and PM levels over the past 20 years, heavy-duty highway 
    diesel engine manufacturers have identified new technologies and 
    approaches that today offer promise for significant new reductions. New 
    technological options are available to manufacturers of heavy-duty 
    gasoline engines as well. The emerging technological potential for much 
    cleaner highway heavy-duty engines is discussed further in Section VIII 
    below.
        In addition, many engines used in highway trucks have similar 
    counterparts that are used in certain nonroad equipment applications. 
    The first emission control regulations covering these heavy-duty 
    nonroad engines have been only recently established; these new 
    standards are less stringent than current standards for similar heavy-
    duty engines intended for highway use. A strong potential exists for 
    current highway engine emission control technology to be applied in 
    many cases to heavy-duty nonroad engines (even though differences in 
    application and usage complicate direct translation of the technology), 
    representing a future avenue for additional mobile source emission 
    reductions.
        Recognizing the need for additional NOX (and PM) control 
    measures at the national level to address air quality concerns in a 
    number of parts of the country and the growing contribution of the 
    heavy-duty engine sector to ozone (and PM) problems, EPA recently held 
    a series of discussions with the California Air Resources Board (CARB) 
    and representatives of the heavy-duty engine manufacturing industry. 
    The purpose of these discussions was to exchange views on the 
    appropriateness and feasibility of new emission standards for heavy-
    duty engines. Based on these discussions, a Statement of Principles 
    (SOP) regarding highway heavy-duty engines has been signed by these 
    parties.
        The SOP is described in more detail in Section VII of this notice 
    and is attached as an Appendix. It addresses NOX, PM, and NMHC 
    standards for highway heavy-duty engines starting in model year 2004, 
    the important role that fuel may play in achieving these standards, a 
    procedure to reevaluate the appropriateness of these standards in 1999, 
    the intent of the parties to undertake development of a joint industry/
    government research program aimed at meeting and exceeding the NOX 
    and PM levels discussed in the SOP, and the intent of the parties to 
    continue discussions with others with the goal of signing a similar SOP 
    with respect to nonroad heavy-duty engines. Other important elements of 
    the SOP are also discussed in Section VII.
        The main purposes of today's ANPRM are to provide an early focus 
    for an open and comprehensive discussion of the issues involved in 
    achieving additional emission reductions from heavy-duty engines and to 
    make the SOP available to the public for comment on specific 
    
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    emission reductions from highway heavy-duty engines.4 The rest of 
    the ANPRM is organized as follows: Section II summarizes the public 
    health and welfare needs for this initiative and trends in overall 
    nationwide NOX, VOC, and PM emissions; Section III describes the 
    contribution of HDEs to overall emissions; Section IV summarizes the 
    need for control of heavy-duty engines; Section V provides the history 
    and status of highway heavy-duty engine emission standards; Section VI 
    summarizes a range of requests for action that EPA has received to 
    date; Section VII reviews the development and content of the Statement 
    of Principles; Section VIII discusses some approaches to highway HDE 
    emission control; and Section IX describes EPA's plans for involving 
    the public in the upcoming rulemaking process. The complete text of the 
    Statement of Principles is included as an Appendix to today's Notice.
    
        \4\ Also, in a letter to certain organizations related to clean 
    air issues in California, EPA agreed that it would issue an ANPRM 
    regarding national standards for highway HDEs.
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    II. Health Concerns and Air Quality Issues: NOX, VOC, Ozone, 
    and Particulate Matter
    
    A. Health and Environmental Effects Related to NOX, VOC, and Ozone 
    5
    
        \5\ Information cited in this section and other related 
    information on health effects of NOX, VOC and Ozone are 
    available from Docket A-95-27.
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        Oxides of nitrogen comprise a family of highly reactive gaseous 
    compounds that contribute to air pollution in both urban and rural 
    environments. Because NOX emissions are produced during the 
    combustion of fuels at high temperatures, the primary sources of 
    atmospheric NOX include both stationary sources, such as power 
    plants and industrial boilers, and mobile sources, such as light- and 
    heavy-duty vehicles as well as construction, agricultural, and other 
    nonroad equipment. NOX is directly harmful to human health and the 
    environment, contributes to particulate pollution, and plays a critical 
    role in the formation of atmospheric ozone. The current primary 
    (health-based) and secondary (welfare-based) national ambient air 
    quality standards (NAAQS) for NO2 are both set at a concentration 
    of 0.053 parts per million (ppm), on an annual average.
        Exposure to NO2 can reduce pulmonary function and increase 
    airway irritation in healthy subjects as well as people with pre-
    existing pulmonary conditions. In children, exposure to NO2 at or 
    near the level of the ambient standard appears to increase the risk of 
    respiratory illness.6 NOX and its transformation products 
    (e.g., nitric acid, peroxyacetyl nitrate (PAN) and nitrate particles) 
    also contributes to a number of adverse environmental impacts such as 
    the overgrowth of algae and oxygen depletion (eutrophication).7 
    NOX and its products contribute to acid rain, which affects both 
    terrestrial and aquatic ecosystems, including acidification of surface 
    waters, reduction in fish populations, damage to forests and associated 
    wildlife, soil degradation, damage to materials, monuments, buildings, 
    etc., and reduced visibility.8
    
        \6\ Air Quality Criteria Document for Oxides of Nitrogen, EPA-
    600/8-91/049aF-cF, August 1993 (NTIS #: PB92-17-6361/REB,-6379/REB-
    6387/REB).
        \7\ Deposition of Air Pollutants Into the Great Waters: First 
    Report to Congress, EPA-453/r-93-055, May 1994.
        \8\ ``Acid Deposition Standard Feasibility Study, A Report to 
    Congress,'' prepared for the U.S. Environmental Protection Agency by 
    the Cadmus Group, Inc., under Contract Number 68-D2-0168, February 
    1995.
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        NOX is also a primary precursor to atmospheric ozone 
    (O3). (Volatile organic compounds (VOC), composed of a very large 
    number of different hydrocarbons (HC) and other organic compounds, are 
    also primary precursors to ozone. Their effects as a class of compounds 
    on health are generally considered in terms of ozone health effects; 
    health implications of individual toxic compounds are not separately 
    addressed in this Notice.) The rate of ozone creation depends on highly 
    complex interactions between VOCs and NOX in the presence of 
    sunlight. However, in areas with high VOC to NOX ratios, which 
    includes most of the area covering the eastern United States, ozone 
    formation is NOX limited, and NOX reductions will reduce 
    ozone levels. Areas with lower VOC to NOX ratios (particularly the 
    core of many large highly urbanized nonattainment areas) are VOC 
    limited and NOX emissions will interact with ozone to reduce ozone 
    levels. However, in NOX limited areas, downwind of these same 
    areas, NOX reductions will reduce ozone levels.
        Ozone is a highly reactive chemical compound which can affect both 
    biological tissues and man-made materials. Ozone can affect human 
    pulmonary and respiratory health--symptoms include chest pain, 
    coughing, and shortness of breath.9 Studies, to date, indicate 
    that at the current standard these effects are reversible when exposure 
    stops.
    
        \9\ Air Quality Criteria Document for Ozone and Related 
    Photochemical Oxidants (External Review Draft), EPA-600/AP-93/004a-
    c, February, 1995 (NTIS #: PB94-17-3127, -3135, -3143).
        The presence of elevated levels of ozone is of concern in rural 
    areas as well. Because of its high chemical reactivity, ozone causes 
    damage to vegetation. Estimates based on experimental studies of the 
    major commercial crops in the U.S. suggest that ozone may be 
    responsible for significant agricultural crop yield losses. In 
    addition, ozone causes noticeable leaf damage in many crops, which 
    reduces marketability and value. Finally, there is evidence that 
    exposures to ambient levels of ozone which exist in many parts of the 
    country are also responsible for forest and ecosystem damage. Such 
    damage may be exhibited as leaf damage, reduced growth rate, and 
    increased susceptibility to insects, disease, and other environmental 
    stresses and has been reported to occur in areas that attain the 
    current standard. There are complexities associated with evaluating 
    such effects due to the wide range of species and biological systems 
    introduce significant uncertainties.
    
    B. Health and Other Effects Related to Particulate Matter 10
    
        Air pollutants collectively called particulate matter (PM) include 
    dust, dirt, soot, smoke and liquid droplets directly emitted into the 
    air by sources such as factories, power plants, cars, trucks, 
    woodstoves/fireplaces, construction activity, forest fires, 
    agricultural activities such as tillage, and natural windblown dust. 
    Particles formed secondarily in the atmosphere by condensation or the 
    transformation of emitted gases such as SO2, NOX, and VOCs 
    are also considered particulate matter.
    
        \10\ Information cited in this section and other related 
    information on the health effects of particulate matter are 
    available for the public from Docket A-95-27.
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        Based on studies of human populations exposed to high 
    concentrations of particles (sometimes in the presence of SO2), 
    and laboratory studies of animals and humans, there are major human 
    health concerns associated with PM. These include deleterious effects 
    on breathing and respiratory systems, aggravation of existing 
    respiratory and cardiovascular disease, alterations in the body's 
    defense systems against foreign materials, damage to lung tissue, 
    carcinogenesis, and premature death. The major subgroups of the 
    population that appear to be most sensitive to the effects of 
    particulate matter include individuals with chronic obstructive 
    pulmonary or cardiovascular disease, 
    
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    those with influenza, asthmatics, the elderly, and children. 
    Particulate matter also soils and damages materials, and fine particles 
    are a major cause of visibility impairment in the United States.11
    
        \11\ Air Quality Criteria for Particulate Matter (External 
    Review Draft), EPA-600/AP-95/001a-c, April 1995 (NTIS #PB95-22-1727, 
    -1735, -1743).
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    C. Need for NOX and VOC Control; Ozone and Other Air Quality 
    Management Issues
    
        States are obligated under the Clean Air Act to submit State 
    Implementation Plans (SIPs) demonstrating how each nonattainment area 
    will reach attainment of the ozone NAAQS. For nonattainment areas 
    designated as serious or worse, this obligation involves the use of 
    photochemical grid modeling (e.g., Urban Airshed Modeling, or UAM) for 
    each nonattainment area. Although these attainment demonstrations were 
    due November 15, 1994, the magnitude of this modeling task, especially 
    for areas which are significantly affected by transport of ozone and 
    precursors generated outside of the nonattainment area, has delayed 
    many states in submitting complete modeling results.
        Recognizing these challenges, EPA recently issued guidance on ozone 
    demonstrations,12 based on a two-phase approach for the submittal 
    of ozone SIP attainment demonstrations. Under the first phase, the 
    state is required to submit a plan implementing a set of specific 
    control measures to obtain major reductions in ozone precursors along 
    with limited UAM modeling. The second phase includes a two-year process 
    during which EPA, the states, regional associations, and other 
    interested parties can improve emission inventories and modeling and 
    better assess regional and local impacts and control strategies on 
    ozone attainment. These analyses are then to be used by states as their 
    basis for demonstrating ozone attainment plans in their phase II SIPs.
    
        \12\ Memorandum from Mary D. Nichols, Assistant Administrator 
    for Air and Radiation, to EPA Regional Administrators, re Ozone 
    Attainment Demonstrations, March 2, 1995.
        Modeling results already available and the need for two-phased 
    ozone attainment plans highlight the fact that ozone pollution is a 
    regional problem, not simply a local or state problem. Ozone itself and 
    its precursors are transported long distances by winds and 
    meteorological events. Thus, achieving ozone attainment for an area and 
    thereby protecting its citizens from ozone-related health effects often 
    depends on the ozone and/or precursor emission levels of upwind areas. 
    Local stationary source NOX and VOC controls will assist 
    nonattainment areas toward their ozone reduction goals, but for many 
    areas with persistent ozone problems, attainment of the ozone NAAQS 
    will require broader control strategies for both NOX and VOC. As a 
    result, effective national ozone control requires an integrated 
    strategy which combines cost-effective approaches in both the mobile 
    and stationary source arenas at both the local and national levels.
        The rate of ozone creation depends on highly complex interactions 
    between VOCs and NOX in the presence of sunlight. While regional 
    concentrations and transport of precursor pollutants have a significant 
    role in determining the rate of ozone production in many areas, local 
    conditions are also important and may be predominant factors in some 
    cases. Generally, the formation of ozone in locations with low VOC to 
    NOX ratios tends to be VOC limited. Low VOC to NOX ratios are 
    characteristic of the central core of many highly urbanized 
    nonattainment areas, which may thus be dependent on VOC control for 
    effective ozone reduction. On the other hand, in areas with higher VOC 
    to NOX ratios, ozone formation is NOX limited, and NOX 
    reduction strategies are required for effective ozone control. Such 
    conditions occur over broad regions of the U.S., including many areas 
    downwind of large urban centers. As concluded in a recent report by the 
    National Research Council (NRC), ``the optimal set of controls relying 
    on VOCs, NOX, or, most likely, reductions of both, will vary from 
    one place to the next.'' 13
    
        \13\ National Research Council. Rethinking the Ozone Problem in 
    Urban and Regional Air Pollution. National Academy Press, 
    Washington, D.C., 1991.
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        While both NOX and VOC emissions are subject to various 
    stationary and mobile source regulations, VOCs have often been the 
    primary focus of past ozone abatement strategies, and specific air 
    quality issues regarding NOX emissions have received somewhat less 
    attention. Accordingly, the next sections describe some of the key 
    regional ozone and other air quality problems around the country for 
    which additional NOX controls will be beneficial.
    1. Eastern United States
        There is a growing body of evidence that reduction of regional 
    ozone levels holds the key to the ability of a number of the most 
    seriously polluted areas in the Eastern United States, in both the 
    Southeast and the Northeast, to meet the ozone NAAQS. Regional Oxidant 
    Modeling (ROM) studies conducted by EPA (called the ROMNET and Matrix 
    studies 14) strongly suggest that reducing NOX emissions is 
    the most effective approach for reducing ozone over large geographical 
    areas. (In contrast, as described below, local NOX controls may or 
    may not be helpful in individual nonattainment areas.) At the same 
    time, these studies, as well as ongoing UAM modeling by states, suggest 
    that reduction in VOC emissions may be key to reducing locally 
    generated peak ozone concentrations. Additional NOX control will 
    also contribute to addressing the problems of year-round NOX 
    deposition in the Chesapeake Bay and other nitrogen-limited estuaries 
    15 and acid rain in the eastern part of the country.
    
        \14\ See Regional Ozone Modeling for Northeast Transport 
    (ROMNET), EPA Doc. EPA-450/4-91-002a (June 1991), and Chu, S.H., 
    E.L. Meyer, W.M. Cox, R.D. Scheffe, ``The Response of Regional Ozone 
    to VOC and NOX Emissions Reductions: An Analysis for the 
    Eastern United States Based on Regional Oxidant Modeling,'' 
    Proceedings of U.S. EPA/AWMA International Specialty Conference on 
    Tropospheric Ozone: Nonattainment and Design Value Issues, AWMA TR-
    23, 1993.
        \15\ Deposition of Air Pollutants Into the Great Waters: First 
    Report to Congress, EPA-453/r-93-055, May 1994.
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        In its analysis supporting the approval of a Low Emission Vehicle 
    program in the eastern and northeast states comprising the Ozone 
    Transport Region (OTR),16 EPA reviewed existing work and performed 
    new analysis to evaluate in detail the degree NOX controls are 
    needed.17 These studies showed that 50-75 percent reductions in 
    NOX from 1990 levels would be needed throughout the OTR. These 
    studies also showed that 50-75 percent reductions in VOC would be 
    needed in and near the portion of the OTR comprising the Northeast 
    urban corridor. The studies also concluded that transport of ozone and 
    precursors from upwind areas is a significant contributor to ozone 
    exceedances downwind in essentially all nonattainment areas in the OTR.
    
        \16\ Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, 
    Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, 
    District of Columbia, and northern Virginia.
        \17\ Environmental Protection Agency, Low Emission Vehicle 
    Program for Northeast Ozone Transport Region; Final Rule, 60 FR 
    48673, January 24, 1995.
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        More recently, three new studies have become available which 
    confirm the conclusions of the earlier studies. In one of these, the 
    Agency performed new ROM analyses evaluating the eastern third of the 
    U.S. and southern Canada.18 
    
    [[Page 45584]]
    Taken together, these studies strongly support the view that NOX 
    emission reductions in the range of 50-75 percent will be needed in 
    each state in the OTR and VOC reductions in the range of 50-75 percent 
    will be needed in and near the Northeast urban corridor to reach and 
    maintain attainment.
    
        \18\ Environmental Protection Agency, ``Summary of EPA Regional 
    Oxidant Model Analyses of Various Regional Ozone Control 
    Strategies,'' November 28, 1994; Kuruville, John et al., ``Modeling 
    Analyses of Ozone Problem in the Northeast,'' prepared for EPA, EPA 
    Document No. EPA-230-R-94-108, 1994; Cox, William M. and Chu, Shao-
    Hung, ``Meteorologically Adjusted Ozone Trends in Urban Areas: A 
    Probabilistic Approach,'' Atmospheric Environment, Vol. 27B, No. 4, 
    pp 425-434, 1993.
    2. Other Regions
        A recent Southern Oxidant Study (SOS) report 19 describes the 
    results of research showing that, in the south, relatively high 
    concentrations of ozone accumulate in both rural and urban areas. 
    Although the rural ozone levels tend to be lower than in urban areas, 
    and are generally in compliance with the current ozone NAAQS, the rural 
    ozone concentrations are still high enough to inhibit photosynthesis, 
    thus reducing agricultural yields and causing damage to forests and 
    ornamental plants.
    
        \19\ The State of the Southern Oxidant Study (SOS): Policy-
    Relevant Findings in Ozone Pollution Research, 1988-1994. North 
    Carolina State University, April 1995.
    ---------------------------------------------------------------------------
    
        These rural concentrations of ozone and its precursors create a 
    relatively high ozone background on which the ozone plumes from 
    stationary and area sources in urban areas are superimposed. As a 
    result, modeling in the Atlanta metropolitan area, designated as a 
    serious ozone nonattainment area, suggests that a 90 percent decrease 
    in NOX emissions will be required to achieve the current NAAQS in 
    Atlanta.
        Modeling studies performed to date for the states surrounding Lake 
    Michigan (Wisconsin, Illinois, Indiana, and Michigan) indicate that 
    reducing ozone transported into this region has a significant effect on 
    the number and stringency of local control measures likely to be needed 
    to meet the ozone NAAQS. Without such reductions, these studies suggest 
    that the necessary degree of local control will be very difficult to 
    achieve. The EPA Matrix study referenced above also indicates that 
    NOX control will be effective in reducing regional ozone in the 
    Midwest. This suggests that new reductions in NOX emission will be 
    helpful in meeting the NAAQS in the Lake Michigan area, even though 
    NOX control in the immediate vicinity of and within major 
    nonattainment areas near Lake Michigan do not appear to contribute to 
    attainment in these areas.
        The ozone SIP that the State of California has submitted to EPA for 
    approval relies on NOX and VOC reductions for most California 
    nonattainment areas to demonstrate compliance with the NAAQS. 
    Specifically, the revised SIP projects that the following NOX 
    reductions will be required: South Coast, 59 percent; Sacramento, 40 
    percent; Ventura, 51 percent; San Diego, 26 percent; and San Joaquin 
    Valley, 40 percent. For VOC, the required reductions will be the 
    following: South Coast, 79 percent; Sacramento, 38 percent; Ventura, 48 
    percent; San Diego, 26 percent; and San Joaquin Valley, 40 percent. 
    Transported ozone and precursor emissions are also an important factor 
    in California's need for additional NOX controls.20
    
        \20\ In addition, the revised SIP concludes that secondary 
    formation of nitrate particulate from NOX (primarily ammonium 
    nitrate) contributes to the particulate problem in the South Coast 
    Air Basin and the San Joaquin Valley. Reduction of this fraction of 
    the total PM will require additional NOX emission reductions.
    ---------------------------------------------------------------------------
    
        The Agency requests comment on these studies and the application of 
    their findings to the planned actions in this Notice as well as any 
    additional data or analysis that would inform any future actions.
    4. Waivers of Local Stationary Source NOX Control Requirements
        In some cases, states with nonattainment areas subject to NOX 
    Reasonably Available Control Technology (RACT) requirements for 
    stationary sources have petitioned EPA for a waiver from these 
    requirements. EPA guidance on such waivers provides that waivers may be 
    granted if states show that reducing NOX in a nonattainment area 
    would not contribute to attainment of the ozone NAAQS within the same 
    nonattainment area.21 EPA's policy is to limit the assessment of 
    the petitions to the effect that NOX reductions within a 
    nonattainment area have on that specific area's ability to meet the 
    NAAQS (i.e., an assessment of pollutant transport outside the area is 
    not made). EPA has separate authority under the CAA to require a state 
    to reduce emissions from sources where there is evidence showing that 
    such emissions would contribute significantly to nonattainment or 
    interfere with maintenance of attainment in other states.
    
        \21\ ``Section 182(f) Nitrogen Oxides (NOX) Exemptions-- 
    Revised Process and Criteria,'' EPA Memo from John S. Seitz, 
    Director, OAQPS, to Regional Air Directors, February 8, 1995.
    ---------------------------------------------------------------------------
    
        EPA's approval of a NOX exemption is granted on a contingent 
    basis.22 That is, a monitoring-based exemption lasts for only as 
    long as the area's monitoring data continue to demonstrate attainment 
    and a modeling-based exemption lasts for only as long as the area's 
    modeling continue to demonstrate attainment without NOX reductions 
    from major stationary sources.23
    
        \22\ ``Section 182(f) Nitrogen Oxides (NOX) Exemptions-- 
    Revised Process and Criteria,'' EPA Memo from John S. Seitz, 
    Director, OAQPS, to Regional Air Directors, May 27, 1994.
        \23\ NOX Supplement to the General Preamble, 57 FR 55628 
    (Nov. 25, 1992).
    ---------------------------------------------------------------------------
    
        Given these circumstances, EPA's approval of NOX waivers for 
    certain areas should not be viewed as contradictory to the 
    consideration of regional and national measures to reduce NOX 
    emissions. As discussed above, new regional and/or national NOX 
    controls are needed to obtain the NAAQS designed to protect the public 
    health.
    5. National NOX and VOC Emissions Trends 24
    
        \24\ For today's notice, EPA has assembled data available to 
    date projecting emissions from various sources into the future. The 
    data comes from the EPA ``Trends Document'' (National Air Pollutant 
    Emission Trends, 1900-1993, EPA-454/R-94-027, October 1994), MOBILE5 
    emissions modeling, and work performed under EPA's contract with 
    E.H. Pechan and Associates. EPA expects to continue to revise and 
    improve its projections of emissions and will discuss and rely on 
    such updated information in future rulemakings.
    ---------------------------------------------------------------------------
    
        Figure 1 displays projected total NOX emissions over the time 
    period 1990 to 2020 as well as stationary and mobile source components 
    over the same period. Figure 2 presents similar data for VOC emissions 
    for the period 1990 to 2010 (later-year projections for VOC are under 
    development).25 As the figures show, a similar pattern is 
    projected for both of these ozone precursor emissions. Initially, the 
    projections indicate that the national inventories will decrease over 
    the next few years as a result of continued implementation of existing 
    CAA stationary and mobile-source NOX control programs. After the 
    year 2000, however, as the implementation of new CAA programs is 
    completed and the 
    
    [[Page 45585]]
    pressure of growth continues, these downward trends are expected to 
    reverse, and national VOC and NOX emissions are both expected to 
    rise again.
    
        \25\  The data in these and the succeeding figures in this ANPRM 
    take into account the expected effects of various CAA control 
    programs which have been promulgated to date, including Tier I 
    tailpipe standards, new evaporative emission test procedures, 
    enhanced inspection and maintenance requirements, reformulated 
    gasoline, oxygenated fuels, and California LEV (Low Emission 
    Vehicle) requirements. Nonroad NOX emission projections also 
    reflect the future effects of existing nonroad emission regulations. 
    The potential effects of contemplated National LEV requirements are 
    not reflected in the data. In these figures, nonroad emission data 
    includes emissions from a broad range of off-highway sources 
    including, locomotives, aircraft and marine vessels.
    ---------------------------------------------------------------------------
    
        Figures 1 and 2 present emissions data for the entire country. In 
    nonattainment areas, the fraction of NOX and VOC total emissions 
    contributed by mobile sources on average is greater than in the 
    nationwide assessment and is in excess of the stationary source 
    contribution.
    
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    D. Need for PM Control; PM Air Quality Issues and Emission Trends
    
        The overwhelming proportion of PM-10 emissions is created by wind 
    erosion, accidental fires, fugitive dust emissions (from road surfaces, 
    agricultural tilling, construction sites, etc.), and other 
    miscellaneous sources. As much as 85 percent of PM-10 in nonattainment 
    areas can be composed of these ``crustal'' and miscellaneous materials. 
    Since these sources are not readily amenable to regulatory standards 
    and controls, when considering the need for PM controls it is 
    appropriate to focus on the ``controllable'' portion of the particulate 
    pollution problem. The result is shown in Figure 3, which displays 
    national trends in PM-10 levels from stationary and mobile sources, 
    projected for the twenty year period 1990 to 2010. Similar to the 
    pattern discussed above for VOC and NOX emissions, the figure 
    shows that total PM from these sources will decline slightly as the 
    beneficial effects of the 1990 CAA Amendments continue to be felt. 
    However, in the absence of additional controls, mobile source and 
    industrial source emissions of PM-10 levels are expected to rise after 
    2000.
    
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        Currently, there are 44 PM-10 nonattainment areas in 18 states. 
    More generally, diesel emissions contribute significantly to higher 
    than average PM levels that tend to occur in high-population, high-
    traffic urban settings. These areas frequently have elevated ambient 
    levels of other air pollutants as well. To the extent that higher PM 
    exposures result from these factors, control of PM emissions from 
    diesel engines could be expected to provide public health and welfare 
    benefits for a relatively large number of individuals.
    
    III. Contribution of Heavy-Duty Engines to National NOX, VOC, 
    and PM Emissions
    
        Heavy-duty highway and nonroad engines contribute significantly to 
    levels of NOX and are also an important source of VOC (as a result 
    of HC emissions) and PM in most parts of the country. This section 
    describes the current and expected future role of HDEs in contributing 
    to the nation's major air pollution problems.
    
    A. HDE Contribution to National NOX Emissions
    
        Figure 4 shows the total mobile source NOX inventory by 
    emission source (light-duty highway vehicles, heavy-duty highway 
    vehicles, and nonroad engines), projected over the next 25 years.
    
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    [[Page 45592]]
    
    
    B. HDE Contribution to National VOC Emissions
    
        Figure 5 shows the total mobile source VOC inventory by emission 
    source. The figure shows that light-duty vehicle emissions can be 
    expected to decline for some years but then begin rising in the 2005 
    time frame. VOC emissions from highway heavy-duty engine and nonroad 
    sources are projected to rise slightly throughout this period.
    
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    C. HDE Contribution to National PM Emissions
    
        Projected mobile source trends for PM-10 are shown in Figure 
    6.26 The figure shows that, over the next 15 years, the 
    contribution of highway sources including HDEs to PM-10 emissions are 
    expected to decrease and then remain relatively constant well into the 
    next decade, while PM emissions from nonroad sources are expected to 
    increase.
    
        \26\ Environmental Protection Agency, ``National Air Pollutant 
    Emission Trends, 1900-1993,'' EPA-454/4-94-027, October 1994.
    
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    IV. The Need for New Heavy-Duty Engine Emission Control
    
        The Agency believes several factors combine to support rulemaking 
    to reduce NOX, HC, and PM emissions from highway and nonroad 
    heavy-duty engines in the next decade. First, HDE emission controls 
    offer a means to address at the national level the need for new 
    approaches to NOX, HC, and PM reductions that is described in 
    Section II. As explained more fully above, local measures alone to 
    control NOX, HC and PM will prove insufficient if all areas of the 
    country are to achieve and maintain attainment of the ozone and PM 
    NAAQS in the years ahead. Heavy-duty engines, like other mobile 
    sources, represent an emissions source that crosses attainment areas 
    and state boundaries; trucks and buses often travel long distances 
    while nonroad heavy-duty engines power a variety of equipment used in 
    both urban and rural areas, and are often relocated to different 
    regions of the country as needed.
        Second, the projections in Section III above show that heavy-duty 
    engines contribute in varying degrees to the national inventory of 
    NOX, HC, and PM emissions.27 Third, an effort now to 
    implement national HDE controls may prevent a patchwork of regulation 
    where some states require HDE controls while other states do not. 
    Indeed, engine manufacturers felt it was very important that the new 
    program which EPA expects to propose regarding highway HDEs (see 
    Section VII below) provide for the harmonization of requirements 
    between EPA and CARB, resulting in a single set of heavy-duty standards 
    applicable in all 50 states. A national program thus appears to offer 
    the most efficient way for states, engine manufacturers, and EPA to 
    implement additional HDE controls. Fourth, since states must soon 
    finalize SIPs demonstrating attainment in the years ahead, action on 
    additional HDE controls will allow states to incorporate the expected 
    reductions from HDE controls in their SIPs.
    
        \27\ For PM emissions, the projections show that the mobile 
    source contribution is growing; available data shows that heavy-duty 
    highway and nonroad engines represent significant fractions of 
    mobile source emissions.
    ---------------------------------------------------------------------------
    
        Fifth, with respect to highway HDEs, cost effective technology 
    options now appear to be within reach which can achieve very large 
    NOX emission reductions from new highway HDEs manufactured in 
    model year 2004 and subsequent years (see Section VIII below for a more 
    detailed discussion of this issue). The Agency is optimistic that, with 
    continued investment in research and development by the highway HDE 
    manufacturers, and with cooperation between EPA, CARB, the 
    manufacturers, and the oil refining industry, technological barriers 
    which have prevented NOX emissions from diesel HDEs from reaching 
    levels characteristic of gasoline engines will be overcome. For the 
    benefits of these NOX reductions to be realized to a significant 
    degree in the next decade, the Agency believes that this work must 
    begin soon.
        Finally, with respect to nonroad heavy-duty engines, EPA believes 
    that there is the potential to apply current highway HDE emission 
    control technology to many nonroad HDEs, providing an avenue for 
    significant additional mobile source emission reductions. Only recently 
    have the first emission controls been applied to heavy-duty nonroad 
    engines, and standards are currently set at levels significantly higher 
    than current highway heavy-duty engine standards. While control of some 
    or all nonroad heavy-duty engines raises special issues such as the 
    lack of a vehicle registration system and the potential difficulty of 
    ``packaging'' engines on a variety of equipment types, many engines 
    used in highway trucks have similar counterparts that are used in 
    nonroad equipment applications. It therefore makes sense to explore 
    ways to apply highway HDE emission control technology to nonroad HDEs.
        The Agency is interested in comment on the role of NOX 
    emissions in contributing to high ozone levels over broad areas and the 
    need for national HDE controls to address NOX and ozone levels. In 
    addition the Agency solicits comment on other approaches such as local 
    and regional controls.
    
    V. Background on Highway Heavy-Duty Engine Standards
    
        Under EPA's classification system, vehicles with a gross vehicle 
    weight rating (GVWR) over 8,500 pounds are considered heavy-duty 
    vehicles. (The State of California classifies the lighter end of EPA's 
    heavy-duty class as ``medium-duty vehicles.'') Heavy-duty engines are 
    used in a wide range of heavy-duty vehicle categories, from small 
    utility vans to large trucks. Because one type of heavy-duty engine may 
    be used in many different applications, EPA emission standards for 
    heavy-duty vehicles are based on the emissions performance of the 
    engine (and any associated aftertreatment devices) separate from the 
    vehicle chassis. Testing of a heavy-duty engine consists of exercising 
    the engine over a prescribed duty cycle of engine speeds and loads 
    using an engine dynamometer.
        Emissions from heavy-duty engines are measured in grams of 
    pollutant per brake horsepower-hour (g/bhp-hr) or, in more recent 
    regulations, in grams per kilowatt hour (g/kw-hr). These units for 
    emission rates recognize that the primary purpose of heavy-duty engines 
    is to perform work and that there is a large variation in work output 
    among the engines used in heavy-duty applications. Under this system, 
    standards per unit of work are the same for all heavy-duty engines.
        Emission standards have been in place for highway diesel and 
    gasoline heavy-duty engines since the early 1970s. The first 
    regulations focused on control of emissions of smoke. Subsequent 
    regulations broadened emission control requirements to include gaseous 
    and particulate emissions. The 1990 amendments to the Clean Air Act 
    required EPA to set more stringent standards for NOX emissions 
    from all heavy-duty highway engines and for PM from buses. 42 U.S.C. 
    7521(a)(3), 7521(f), 7554(b).
        The current exhaust emission standards for highway heavy-duty 
    diesel and gasoline engines are presented in Table 1. Standards for 
    ``urban buses'' (large transit buses), which specify more stringent PM 
    levels than those applying to other heavy-duty engines, are displayed 
    separately in the table.
    
                                                                            
    
    [[Page 45597]]
                                     Table 1.--Highway Heavy-Duty Emission Standards                                
    ----------------------------------------------------------------------------------------------------------------
                                                                                    Oxides of            Diesel     
                    Year                   Hydrocarbons (g/   Carbon Monoxide    nitrogen (g/bhp-   particulate (g/ 
                                               bhp-hr)           (g/bhp-hr)            hr)              bhp-hr)     
    ----------------------------------------------------------------------------------------------------------------
    Diesel:                                                                                                         
        1991-93.........................                1.3               15.5                5.0               0.25
        1994-97.........................                1.3               15.5                5.0               0.10
        1998............................                1.3               15.5                4.0               0.10
    Urban buses:                                                                                                    
        1991-92.........................                1.3               15.5                5.0               0.25
        1993............................                1.3               15.5                5.0               0.10
        1994-95.........................                1.3               15.5                5.0               0.07
        1996-97.........................                1.3               15.5                5.0              *0.05
        1998............................                1.3               15.5                4.0              *0.05
    Gasoline:                                                                                                       
    1991-97:                                                                                                        
        (A).............................                1.1               14.4                5.0                4.0
        (B).............................                1.9               37.1                5.0                4.0
    1998:                                                                                                           
        (A).............................                1.1               14.4                4.0                3.0
        (B).............................                1.9               37.1                4.0               4.0 
    ----------------------------------------------------------------------------------------------------------------
    Note: ``(A)'' denotes the standard for engines in trucks  14,000 lbs. GVWR.                          
    ``(B)'' denotes the standard for engines in trucks  14,000 lbs. GVWR.                                
    *.07 g/bhp-hr in-use.                                                                                           
    
    
        Under Section 202(a)(3), emission standards for heavy-duty highway 
    engines are set at the ``greatest degree of emission reduction 
    achievable through the application of technology which the 
    Administrator determines will be available for the model year to which 
    such standards apply, giving appropriate consideration to cost, energy, 
    and safety factors associated with the application of such technology'' 
    (42 U.S.C. 7521(a)(3)(A)). In addition, Section 202(a)(3) provides that 
    highway heavy-duty engine manufacturers will have four model years of 
    lead time before any new emission standards may be implemented (42 
    U.S.C. 7521(a)(3)(C)). The Act also provides that standards for heavy-
    duty engines apply for at least three model years to provide stability 
    to any heavy-duty standards. Id. Finally, the Act precludes new 
    NOX emission standards for heavy-duty highway engines before the 
    model year 2004. 42 U.S.C. 7521(b)(1)(C).
    
    VI. Summary of Public Support for EPA To Take Action
    
        Several states, public interest groups and environmental 
    organizations, trucking associations, and others have strongly 
    encouraged EPA to pursue additional NOX, HC, and PM emissions 
    reductions from HDEs through national programs. The Agency has received 
    numerous letters encouraging EPA to move forward with a national 
    program to reduce heavy-duty engine emissions. In December of 1994, 
    several organizations including the American Lung Association and the 
    Natural Resources Defense Council sent a letter to the EPA Assistant 
    Administrator for Air and Radiation requesting that EPA tighten the 
    heavy-duty engine standards to 0.05 g/bhp-hr for particulates and 2.0 
    g/bhp-hr for NOX.28 Jim Edgar, Governor of Illinois, sent a 
    letter to U. S. Senator Paul Simon in March of 1995, urging him to 
    request that EPA implement national rules to reduce ozone precursor 
    emissions from, among other sources, heavy-duty engines. The California 
    Air Resources Board signed a Memorandum of Understanding with EPA in 
    April, 1995 to undertake joint efforts in support of EPA's development 
    of a national program for the control of NOX, PM, and HC emissions 
    from heavy-duty engines. In addition, the ozone SIP submitted by the 
    State of California relies on EPA to set national standards for highway 
    heavy-duty engines at the level of 2.0 g/bhp-hr and requests such 
    action. During May and June of 1995 the Administrator received letters 
    from the State and Territorial Air Pollution Program Administrators/
    Association of Local Air Pollution Control Officials (STAPPA/ALAPCO), 
    the Northeast States for Coordinated Air Use Management (NESCAUM), and 
    the Mid-Atlantic Regional Air Management Association (MARAMA) on behalf 
    of their member states, requesting that EPA implement new national 
    controls for heavy-duty engine emissions. The Northeast Ozone Transport 
    Commission adopted a resolution on June 13, 1995 supporting EPA's 
    efforts to control diesel engine emissions. EPA also received support 
    for reducing the heavy-duty engine NOX standard from the 
    Manufacturers of Emission Controls Association (MECA). On June 22, 
    1995, the Appalachian Mountain Club, a conservation and recreation 
    group with 65,000 members in eleven regional areas, sent a letter to 
    the Administrator that supports EPA's initiative as critical for 
    controlling ozone, PM, acid deposition, and regional haze in the 
    Northeast. In addition to written requests, EPA has received numerous 
    positive comments from concerned individuals, municipalities, and other 
    organizations endorsing a new national control program to reduce 
    emissions from heavy-duty engines.
    
        \28\ Copies of all letters cited and received to date can be 
    obtained from Docket A-95-27, as described at the beginning of this 
    Notice.
    ---------------------------------------------------------------------------
    
    VII. Summary of Government/Industry Statement of Principles
    
        EPA initiated discussions with engine manufacturers, California's 
    Air Resources Board (CARB), and others to begin to explore what 
    additional controls could be implemented to further reduce emissions 
    from heavy-duty engines. As a result of these discussions, EPA, 
    individual members of the highway heavy-duty engine industry, and CARB 
    have signed a Statement of Principles (SOP) regarding future highway 
    HDE emission reductions. The manufacturer signatories 29 represent 
    more than 95 percent of sales by the highway heavy-duty engine 
    industry. With this SOP, presented in its entirety as an Appendix to 
    this notice, the heavy-duty engine 
    
    [[Page 45598]]
    industry has stepped forward to become a leader in environmental 
    protection, and industry and government will work as partners to bring 
    about cleaner air. The following presents a summary of the key elements 
    of this Statement of Principles.
    
        \29\ Caterpillar, Inc., Cummins Engine Company, Inc., Detroit 
    Diesel Corporation, Ford Motor Company, General Motors Corporation, 
    Hino Motors, Ltd., Isuzu Motors America, Inc., Mack Trucks, Inc., 
    Mitsubishi Motors America, Inc., Navistar International, and Volvo 
    Truck Corporation.
    ---------------------------------------------------------------------------
    
        The goal of all Signatories to the SOP is to reduce NOX 
    emissions from highway HDEs to levels approximating 2.0 g/bhp-hr 
    beginning in model year (MY) 2004, while also achieving reductions in 
    HC. Accordingly, the Signatories concur that EPA would issue a notice 
    of proposed rulemaking (NPRM) proposing to implement (1) a combined 
    NOX plus non-methane hydrocarbon (NMHC) standard of 2.4 g/bhp-hr 
    and (2) a combined NOX plus NMHC standard of 2.5 g/bhp-hr together 
    with a NMHC cap of 0.5 g/bhp-hr, with flexibility for an engine family 
    to comply with either of these standards as the manufacturer 
    determines. The Signatories expect that these standards will result in 
    emissions comparable to a NOX standard of 2.0 g/bhp-hr as well as 
    reduced NMHC emissions. In order to facilitate the rulemaking process 
    and solicit additional views, the SOP Signatories concur with EPA's 
    desire to precede the issuance of the NPRM with this ANPRM.
        The Signatories acknowledge that fuel composition 30 has a 
    significant effect on emissions, and commit to making improvements in 
    HDE fuel as appropriate under the CAA to meet the MY2004 emission 
    standards, taking into consideration costs and other relevant factors. 
    The Signatories also recognize that any changes to both certification 
    and commercial fuel specifications would have to become effective no 
    later than October 2003 to ensure fuel availability at the time the 
    MY2004 engine standards would go into effect.
    
        \30\ Representatives of the fuel industry are not parties to 
    this agreement as noted above. EPA will continue to engage the fuel 
    industry in discussions as we proceed to implement the SOP, 
    including identifying formal ways to cooperate with all parties 
    affected by potential heavy-duty engine changes.
    ---------------------------------------------------------------------------
    
        In accordance with the SOP, EPA would in 1999 review any rulemaking 
    adopting the MY2004 standards by issuing a notice providing the 
    opportunity for public comment on whether or not the MY2004 standards 
    are technologically feasible and otherwise appropriate under the CAA. 
    EPA would review the need, feasibility, and cost of the standards under 
    the criteria imposed by the CAA, and would assess whether any fuel 
    improvements that are needed to assist heavy-duty engines in complying 
    with the MY2004 standards would be available nationwide by the 
    appropriate date. After receiving public comment, EPA would take final 
    Agency action. Depending on the results of EPA's review, the MY2004 
    standards would remain at the levels described above or EPA would 
    propose to adjust them. The Signatories expect any adjustment of the 
    standards would not exceed (1) 2.9 g/bhp-hr NOX plus NMHC and (2) 
    3.0 g/bhp-hr NOX plus NMHC with a proportional increase in the 
    NMHC cap (to 0.6 g/bhp-hr), unless improvements to fuel quality are 
    needed but not made.
        Both EPA and California recognize in the SOP the benefits of 
    harmonizing state and federal regulations regarding highway HDEs. 
    California confirms its intent to hold a public hearing regarding 
    harmonization of its regulations for dynamometer-certified engines 
    greater than 8500 lbs. GVWR with the federal regulations adopted under 
    the SOP, provided such action would not compromise California's 
    obligations to comply with state and federal law.
        Neither PM nor CO emission standards change under the SOP. Also, 
    the SOP is premised on the assumption that EPA will not alter federal 
    test procedures for heavy-duty highway engines. With respect to 
    durability, the Signatories commit to work to develop appropriate 
    measures which ensure that emission gains are maintained in-use.
        As part of the SOP, EPA and CARB commit to work cooperatively with 
    industry to develop improved averaging, banking, and trading programs 
    that will create more incentive for early introduction of cleaner 
    engines. At a minimum EPA would, in the NPRM on the MY2004 standards, 
    propose to eliminate any limitations on credit life, propose to 
    eliminate all credit discounts, and solicit comment on the merits of 
    allowing cross-fuel, cross-subclass, and cross-category credit 
    exchanges, to the extent permitted under the CAA.
        A key purpose of the SOP is to provide the HDE industry with 
    increased certainty and stability for their business planning. Without 
    such certainty and stability, industry would not commit to the enormous 
    investment that the SOP standards will require. EPA and CARB in turn 
    acknowledge that industry will be making a commitment and investment 
    that will require more than the minimum period of stability of three 
    years set forth in the CAA.
        The SOP also outlines a plan to undertake a joint industry/
    government research program with the goal of developing engine and fuel 
    technologies which can meet and exceed the MY2004 standards. Pursuant 
    to a separate research agreement, the SOP Signatories and possibly 
    others will try to reduce NOX emissions to 1.0 g/bhp-hr and PM 
    emissions to 0.05 g/bhp-hr while maintaining current highway diesel 
    engine attributes such as performance, reliability, durability, safety, 
    and efficiency.
        Finally, while the SOP focuses on highway HDEs, the SOP Signatories 
    commit to participate in discussions with nonroad HDE and equipment 
    manufacturers to develop a separate SOP by October 1995 addressing 
    emission standards for nonroad HDEs.
        The SOP plan offers a flexible means of achieving a 50 percent 
    reduction in NOX emissions from the 4.0 g/bhp-hr NOX standard 
    that goes into effect beginning in model year 1998. Figure 7 shows the 
    estimated national NOX inventory for highway heavy-duty engines 
    with and without the potential control measures articulated in the SOP. 
    These projections are based on preliminary analysis of available 
    information and subject to revision as EPA continues to analyze such 
    factors as the future growth and turnover of the heavy-duty fleet, in-
    use emission performance, expedited or delayed introduction of new 
    emission reduction technology and other factors.
    
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        For hydrocarbons, EPA expects the NMHC plus NOX standards in 
    the SOP to be equivalent to about half or less of the current HC 
    standards (1.3 g/bhp-hr for diesel engines and 1.1-1.9 g/bhp-hr for 
    gasoline engines). Further, the standards ensure continued control of 
    PM emissions from highway HDEs at current levels (0.1 g/bhp-hr), 
    despite a tendency for PM emissions from diesel HDEs to increase when 
    NOX emissions decrease. Ambient PM reductions may also result from 
    the NOX emission reductions, since NOX contributes to 
    secondary particulate.
        EPA will actively seek to work with both the Signatories to the SOP 
    and the oil refining industry to evaluate the role of fuel improvements 
    in achieving the MY2004 standards. EPA believes the joint industry/
    government research program with the goal of achieving highway HDE 
    emissions of just 1.0 g/bhp-hr NOX and 0.05 g/bhp-hr PM offers an 
    unusual opportunity to work collaboratively for the benefit of the 
    environment. EPA will also continue discussions with the Signatories 
    and others with the aim of achieving an SOP on nonroad heavy-duty 
    engines comparable to this SOP regarding highway heavy-duty engines.
    
    VIII. Approaches to Highway Heavy-Duty Engine Emission Control
    
        Highway heavy-duty engine manufacturers are engaged in ongoing 
    efforts to design and produce the cleaner engines envisioned in the 
    SOP. As with any motor vehicle engine technology, control of emissions 
    from heavy-duty highway engines can come from changes in the design of 
    engines and related hardware, changes to fuels, or some combination of 
    the two. While EPA and the engine manufacturing industry are not yet 
    certain which types of technologies in which combinations might be 
    necessary for manufacturers to reach the standards under consideration, 
    several promising approaches have been identified to date. EPA has 
    prepared a document that describes the causes of highway HDE emissions 
    and several engine-based approaches and exhaust aftertreatment devices 
    to control emissions. This document is available in Docket A-95-27.
        Changes in engine technology or aftertreatment which can reduce HC, 
    NOX and PM emissions must be evaluated with respect to, and bear a 
    close relationship to, the fuel composition the engines will be using. 
    The petroleum industry has changed fuels a number of times in the past 
    either to reduce the emissions from existing vehicles (e.g., gasoline 
    volatility, reformulated gasoline) or to make it possible for engine 
    manufacturers to employ new engine designs or emission control 
    technologies that are sensitive to fuel characteristics (e.g., unleaded 
    gasoline to facilitate the use of catalytic converters, low-sulfur 
    diesel). EPA intends to work jointly with the petroleum industry and 
    the highway HDE manufacturers to develop emission and cost data to help 
    EPA assess the potential role of fuel changes in achieving the 
    standards set forth in the SOP (Section VII above). EPA request comment 
    on the planned approach for assessing the potential role of fuels. In 
    addition, engines designed to use non-petroleum alternative fuels may 
    provide another avenue for manufacturers to comply with more stringent 
    standards.
        EPA is interested in exploring programs and approaches which have 
    the potential to help achieve the goals of the planned regulatory 
    program in the most effective ways, including cost considerations. The 
    Agency expects to continue a broad and open discussion of such 
    potential approaches. The sections below briefly discusses an initial 
    set of ideas which may improve this program; EPA solicits comments on 
    these ideas and encourages suggestions for others.
    
    A. In-Use Emissions Control Elements
    
        Historically, EPA has viewed in-use emissions deterioration as a 
    problem associated more with gasoline engines than diesel engines. EPA 
    believes that deterioration of emissions for diesel engines, especially 
    NOX, has tended to be less than that of gasoline engines because 
    diesel engines currently use fewer aftertreatment or other devices 
    susceptible to in-use degradation. Diesel engine emissions standards 
    have historically been met mainly through overall improvements to the 
    engine and fuel system. These improvements have provided performance, 
    fuel economy, and durability benefits as well.
        As standards are reduced and diesel HDE manufacturers introduce new 
    technologies such as catalysts and exhaust gas recirculation (EGR) 
    solely for emissions control purposes, long-term emissions performance 
    becomes a greater concern. The controls may not function as long as the 
    engines and there may be little incentive for vehicle owners to conduct 
    the repairs on these items needed to ensure emissions control during 
    the very long life of the engines. The HDE engine market has demanded 
    longer-lasting engines, and manufacturers have been successful in 
    increasing engine life. It has been brought to EPA's attention that 
    some current engines accumulate in excess of 600,000 miles before the 
    first rebuild and are often rebuilt many times; the current regulatory 
    ``useful life'' is 290,000 miles. Failure of emissions controls early 
    in the engine's life would offset much of the benefit associated with 
    the expected more stringent standards.
        Programs which encourage manufacturers to design and build engines 
    with very durable emission controls and programs to encourage the 
    proper maintenance and repair of engines and emissions controls are 
    important in achieving the full benefit of emissions standards. The 
    goal is for engines to maintain ``new'' engine performance throughout 
    their in-use operation. EPA is considering changes to current 
    manufacturer emissions durability-related programs to further encourage 
    the design and production of durable emission control systems. Possible 
    changes include extending the period over which manufacturers are 
    responsible for meeting emissions standards (the ``useful life'') and 
    adjusting the regulations relating to the emission-related maintenance 
    that is required of owners by manufacturers to maintain the engine's 
    emissions warranty. EPA is also interested in exploring a program where 
    manufacturers would perform in-use compliance testing and could take 
    advantage of an averaging, banking, and trading program to help achieve 
    in-use compliance. Under such a program, manufacturers would test a set 
    percentage of their in-use engine families each year and could 
    potentially generate emission credits (or take on liabilities) 
    depending on the results of in-use tests relative to the Family 
    Emission Limits established for the engine families involved. EPA 
    believes such a program could offer a cost-effective means of achieving 
    better assurance that standards are being met in-use.
        Proper maintenance and repairs are likely to be important for 
    durable emissions controls, especially for engines designed for a 
    million or more miles. Therefore, EPA is also interested in approaches 
    that involve increased responsibility of the vehicle owner. One 
    approach EPA is considering and on which it invites comment is whether 
    the incorporation of onboard diagnostic systems for emissions 
    monitoring into heavy-duty engine designs would be appropriate. With 
    the increasing availability of sophisticated computer controls, there 
    is a potential to monitor emission control performance and components. 
    EPA is also considering establishing requirements relating to the 
    rebuilding of HDEs as a way of ensuring 
    
    [[Page 45601]]
    that engines and emission controls remain in their proper working 
    condition throughout their full operating life. See 42 U.S.C. 
    7521(a)(3)(D).
    B. Elements to Add Compliance Flexibility
    
        EPA desires to implement any new regulatory programs in ways that 
    minimize the complexity and cost of compliance and maximize flexibility 
    for the regulated industry in complying with the requirements. EPA's 
    chief goal with such approaches would be to encourage the early 
    introduction of cleaner engines whenever possible. EPA may explore a 
    number of options for increasing flexibility to comply with more 
    stringent emissions standards for highway HDEs. The following presents 
    some of the ideas that EPA may consider.
        Averaging, Banking and Trading Program. Currently, an averaging, 
    banking, and trading (ABT) program is in place for heavy-duty highway 
    engines which allows heavy-duty highway engine manufacturers to average 
    the emissions of their various engine families and to generate credits 
    when they introduce cleaner engine families than are required by law. 
    Under this program, a manufacturer may choose to certify an engine 
    family slightly higher or lower than the standard so long as the 
    average emission level for all engine families produced by the 
    manufacturer is at or below the standard. Credit for selling engines 
    that are cleaner than is required can be used immediately, ``banked'' 
    for later use, or traded to another manufacturer.
        Along with the standards discussed above, EPA expects to propose an 
    expanded ABT program that would apply for these new standards. Because 
    exceeding the requirements of the standards under consideration will be 
    very challenging, EPA will propose revisions to the current program 
    which are expected to encourage aggressive emission control development 
    efforts on the part of manufacturers and the early implementation of 
    new technology. EPA will propose changes to the ABT program which would 
    eliminate the discounting of credits over time and would extend the 
    life of the credits indefinitely. EPA will also seek comment on other 
    changes to the ABT programs such as trading between highway and nonroad 
    engines, among the four heavy-duty diesel subclasses, and between 
    heavy-duty diesel and gasoline engines, to the extent permitted under 
    the Act. Such approaches could be difficult to develop in an equitable 
    way given the very different emissions characteristics of these engine 
    types and the fact that the manufacturers' product lines vary.
        Non-Conformance Penalties. In addition to the ABT program described 
    above, another existing program which serves to increase the 
    flexibility for manufacturers of heavy-duty highway engines facing new 
    emission standards is non-conformance penalties (NCPs). The Clean Air 
    Act (Section 206(g)) requires EPA to allow a heavy-duty engine 
    manufacturer to receive a certificate of compliance for an engine which 
    exceeds the standard (but does not exceed an upper limit) if the 
    manufacturer pays an NCP established by EPA through rulemaking. NCPs 
    increase periodically to discourage long-term nonconformance. EPA 
    expects to consider establishing NCPs related to the new heavy-duty 
    emission standards that EPA plans to propose.
        Incentive-Based Approaches. EPA is aware of several program 
    initiatives that could potentially supplement the emission reductions 
    from improved design of new heavy-duty engines. Some of these are 
    described briefly in the following paragraphs. EPA encourages these 
    activities, and in some cases will be supporting their development. Any 
    actions to develop these initiatives, however, will progress in 
    parallel with the planned rulemaking to revise highway heavy-duty 
    engine emission standards, rather than being incorporated into that 
    rule directly.
        Incentive-based approaches to emission control generally seek to 
    provide some credit or reward to encourage businesses to make voluntary 
    changes in operations or procedures to reduce air emissions. In the 
    case of heavy-duty engines, EPA desires incentives that would encourage 
    early introduction of cleaner engines. The ongoing effort to establish 
    these policies must focus on designing a program to ensure that a 
    business's emission reductions are voluntary, quantifiable, and 
    enforceable. Open market trading, which is currently under development 
    by EPA, could be designed to include the credits generated under these 
    programs.
        One potential incentive program would encourage fleets to buy 
    cleaner truck engines earlier than required or buy cleaner engines than 
    otherwise required and make these credits available as Mobile Emissions 
    Reduction Credits. Another idea is to design a program to encourage 
    truck fleet owners to accelerate the turnover of their fleets to newer 
    engines. Typically, this would involve an encouragement to scrap old 
    engines and purchase new lower-emitting engines. Another possibility is 
    to rebuild heavy-duty engines with upgraded components so the ``new'' 
    engine has the emission control capability of a more recent model year.
        Other Approaches. Changes to vehicle operation may also reduce 
    emissions. For example, trucks are frequently allowed to idle for 
    several hours to power accessories such as air conditioners during 
    extended stops. The potential for electrical hookup at truck stops, 
    rest areas, etc., in combination with changes to engine and vehicle 
    designs, could reduce the contribution of extended idling to engine 
    emissions without inconveniencing drivers. Similarly, a program to 
    limit the operating speeds of heavy-duty vehicles, through engine 
    design or other changes, would reduce the excess NOx emissions caused 
    by vehicle operation at high speeds. The reduced fuel consumption 
    associated with these measures would represent a secondary benefit to 
    fleet owners.
        Finally, EPA is working with the freight transportation industry to 
    identify potential infrastructure or regulatory changes that could 
    increase system efficiencies. Any move to improve the efficiency of 
    freight transportation, while reducing costs to industry, would reduce 
    emissions by decreasing the total mileage driven by heavy-duty trucks.
    
    IX. Public Participation
    
        EPA intends for this Notice to provide the basis for the beginning 
    of a broad-based public discussion of the issues surrounding more 
    stringent standards for heavy-duty highway engines presented in the 
    Statement of Principles signed by EPA, CARB, and heavy-duty engine 
    manufacturers. Specifically, the Agency requests comment on the need 
    for heavy-duty engine controls, the proposed timing for Agency action, 
    and on whether the standards and other regulatory provisions planned in 
    the SOP are reasonable and appropriate. EPA also requests comment on 
    the planned approach for dealing with fuels. The Agency requests 
    comment on the plan and need to pursue nonroad heavy-duty engine 
    standards through cooperative discussions with engine and equipment 
    manufacturers and CARB. The Agency also requests any emissions data, 
    technical information, or analyses of technical feasibility which can 
    be used to inform the planned actions. Finally, the Agency requests 
    comment and information on the economic feasibility, including cost 
    considerations for the planned actions.
        EPA expects to issue a Notice of Proposed Rulemaking in the near 
    future 
    
    [[Page 45602]]
    proposing new emission standards for highway heavy-duty engines in 
    accordance with the SOP. The Agency is committed to a full and open 
    regulatory process and looks forward to input from a wide range of 
    interested parties as the rulemaking process develops. These 
    opportunities will likely include meetings and workshops in addition to 
    the minimum required process involving a formal public comment period 
    and a public hearing. EPA encourages all interested parties to become 
    involved in this process as it develops.
    
    X. Statutory Authority
    
        Section 202(a)(3) authorizes EPA to establish emissions standards 
    for new heavy-duty motor vehicle engines. See 42 U.S.C. 7521(a)(3). 
    These standards are to reflect the greatest reduction achievable 
    through the application of technology which the Administrator 
    determines will be available, giving appropriate consideration to cost, 
    energy, and safety factors associated with the application of such 
    technology. This provision also establishes the lead time and stability 
    requirements for these standards, and in addition authorizes EPA to 
    establish requirements to control rebuilding practices for heavy-duty 
    engines. Pursuant to Sections 202(a)(1) and 202(d), these emissions 
    standards apply for the useful life period established by the Agency. 
    See 42 U.S.C. 7521(a)(1), 7521(d).
        Section 213 authorizes EPA to establish emissions standards for new 
    heavy-duty nonroad engines where EPA determines that they cause or 
    contribute to ozone or carbon monoxide air pollution in more than one 
    area that is in nonattainment for ozone or carbon monoxide, or where 
    EPA determines that emissions of other pollutants significantly 
    contribute to air pollution which may reasonably be anticipated to 
    endanger public health or welfare. As with heavy-duty motor vehicle 
    engines, the emissions standards apply for the useful life established 
    by the Agency. See 42 U.S.C. 7547.
        Section 211(c) authorizes EPA to establish controls or prohibitions 
    on fuels and fuel additives for use in highway and nonroad vehicles and 
    engines. EPA may issue such regulations if it determines that (1) any 
    emission product of the fuel or fuel additive causes or contributes to 
    air pollution which may reasonably be anticipated to endanger the 
    public health or welfare, or (2) emissions products of a fuel or fuel 
    additive will impair to a significant degree the performance of any 
    emissions control device or system which is in general use or which the 
    Administrator finds has been developed to a point where in a reasonable 
    time it would be in general use were such regulation promulgated. See 
    42 U.S.C. 7545(c).
        EPA's authority to issue a certificate of conformity upon payment 
    of a non-compliance penalty established by regulations is found in 
    Section 206(g) of the Act. See 42.U.S.C. 7525(g). Other provisions of 
    Title II of the Act, along with Section 301, are additional authority 
    for the measures discussed in this ANPRM.
    
    XI. Unfunded Mandates Reform Act
    
        Under Section 202 of the Unfunded Mandates Reform Act of 1995 
    (``UMRA''), P.L. 104-4, EPA must prepare a budgetary impact statement 
    to accompany any general notice of proposed rulemaking or final rule 
    that includes a Federal mandate which may result in estimated costs to 
    State, local, or tribal governments in the aggregate, or to the private 
    sector, of $100 million or more. Under Section 205, for any rule 
    subject to Section 202 EPA generally must select the least costly, most 
    cost-effective, or least burdensome alternative that achieves the 
    objectives of the rule and is consistent with statutory requirements. 
    Under Section 203, before establishing any regulatory requirements that 
    may significantly or uniquely affect small governments, EPA must take 
    steps to inform and advise small governments of the requirements and 
    enable them to provide input.
        EPA has determined that the requirements of UMRA do not extend to 
    advance notices of proposed rulemaking such as this notice regarding 
    potential controls for heavy-duty engines.
    
    XII. Administrative Designation and Regulatory Analysis
    
        Under Executive Order 12866 (58 FR 51735 (Oct. 4, 1993)), the 
    Agency must determine whether this regulatory action is ``significant'' 
    and therefore subject to OMB review and the requirements of the 
    Executive Order. The order defines ``significant regulatory action'' as 
    any regulatory action (including an advanced notice of proposed 
    rulemaking) 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 entitlements, 
    grants, user fees, or loan programs or the rights and obligations of 
    recipients thereof; or,
        (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.
    
        This Advance Notice was submitted to the Office of Management and 
    Budget (OMB) for review as required by Executive Order 12866. Any 
    written comments from OMB and any EPA response to OMB comments are in 
    the public docket for this Notice.
    
    List of Subjects in 40 CFR Parts 80, 86, and 90
    
        Environmental protection, Administrative practice and procedure, 
    Air pollution control, Diesel fuel, Motor vehicles, Motor vehicles 
    pollution, Reporting and recordkeeping requirements, Research.
    
        Dated: August 24, 1995.
    Carol M. Browner,
    Administrator.
    
    Appendix: Statement of Principles
    
    Statement of Principles
    
        Members of the heavy-duty engine industry, the U.S. 
    Environmental Protection Agency (``EPA''), and the California Air 
    Resources Board (``CARB'') (collectively, the ``Signatories'') 
    recognize the importance of preserving the environment while 
    maintaining a strong industry. This Statement of Principles 
    (``SOP'') increases certainty and stability for the heavy-duty 
    engine industry which is vital for their business planning. It also 
    ensures cleaner air in a manner which is both realistic for industry 
    and responds to environmental needs. With this SOP, the heavy-duty 
    engine industry has stepped forward to become a leader in 
    environmental protection, and industry and government will work as 
    partners to bring about cleaner air.
        This SOP outlines the joint understanding of all Signatories, 
    including issuance by EPA of a Notice of Proposed Rulemaking 
    (``NPRM'') which would be consistent with the points outlined in 
    this document. EPA intends to issue the NPRM in 1995 and plans to 
    promulgate a final rule by the end of 1996. However, this SOP does 
    not change the importance of EPA demonstrating the need for the 
    standards described below and EPA's obligation to meet the criteria 
    of the Clean Air Act (the ``Act'' or ``CAA'') in finalizing any 
    rule, including complying with all applicable rulemaking procedures. 
    In order to facilitate the rulemaking process and to solicit 
    additional views, EPA will precede the issuance of the NPRM with an 
    Advanced Notice of Proposed Rulemaking (``ANPRM'') announcing this 
    SOP.
        1. National Standards for On-Highway Heavy-Duty Engines: For 
    more than two decades, as public concerns about air pollution and 
    smog caused by emissions from heavy-duty trucks and buses have 
    increased, both the industry and the government have responded to 
    protect public health and the environment. Standards have 
    
    [[Page 45603]]
    dropped from levels of 16.0 grams per brake-horsepower/hour (``g/bhp-
    hr'') for Hydrocarbons (``HC'')+Oxides of Nitrogen (``NOX'') in 
    1974 to just 5.0 g/bhp-hr NOX and 1.3 g/bhp-hr HC for heavy-
    duty diesel engines today. The NOX standard will fall again to 
    4.0 g/bhp-hr in 1998. California also has NOX standards of 5.0 
    g/bhp-hr for these engines today and plans to adopt the federal 4.0 
    g/bhp-hr standard for 1998 models.
        Much of the recent focus on improving emissions from diesel 
    engines has centered around reducing smoke and soot from the 
    exhaust. Particulate matter (``PM'') standards for heavy-duty diesel 
    engines have dropped from 0.6 g/bhp-hr in 1988 to just 0.1 g/bhp-hr 
    today. The current PM standards represent a 90% reduction from 
    unregulated levels. The 0.1 g/bhp-hr standard applies both in the 
    California and federal programs. Urban buses have even tighter 
    standards.
        Heavy-duty engine manufacturers have certified vehicles to 
    operate on clean alternative fuels such as natural gas and methanol 
    and continue to research the emissions benefits of alternative and 
    renewable fuels. Clearly, the industry has worked hard to improve 
    technology and provide cleaner vehicles and engines.
        However, in recent years, concern over the role of NOX and 
    HC emissions in causing ozone formation has grown considerably, and 
    reducing both has become an important goal. The opportunity to 
    reduce overall emissions of these pollutants by producing cleaner 
    heavy-duty engines is significant.
        The goal of all Signatories to this SOP is to reduce NOX 
    emissions from on-highway heavy-duty engines to levels approximating 
    2.0 g/bhp-hr beginning in 2004. The Signatories also recognize the 
    need to reduce HC emissions. Because of the air quality importance 
    of reducing hydrocarbon emissions to the maximum extent feasible and 
    in order to maximize industry's ability to achieve low NOX 
    levels, EPA will propose for all heavy-duty engines as part of the 
    NPRM: (1) a combined Non-methane Hydrocarbon (``NMHC'')+NOX 
    standard of 2.4 g/bhp-hr and (2) a combined NMHC+NOX standard 
    of 2.5 g/bhp-hr together with a NMHC cap of 0.5 g/bhp-hr 
    (collectively, the ``Standards''), with flexibility for an engine 
    family to comply with either one of these Standards as the 
    manufacturer determines. It is expected that the Standards would 
    result in emissions comparable to a NOX standard of 2.0 g/bhp-
    hr (i.e., half of the 1998 NOX standard), and also significant 
    reductions in HC emissions.
        While this SOP focuses on NOX and NMHC emissions, the 
    Signatories recognize it does not affect other existing emission or 
    safety standards which pertain to heavy-duty engines. Specifically, 
    all Signatories concur that the feasibility of the Standards would 
    be affected by any changes in PM standards. Thus, this SOP is 
    premised on EPA not changing the 0.1 g/bhp-hr diesel particulate 
    standard currently in effect (or the lower PM standards for urban 
    buses). Further, all Signatories concur that any changes in Carbon 
    Monoxide (``CO'') standards could affect compliance for spark-
    ignited engines. Thus, this SOP is premised on EPA not changing the 
    CO standards currently in effect for heavy-duty engines.
        2. Fuel Improvements: All Signatories acknowledge that fuel 
    composition has a significant effect on emissions and that changes 
    in the composition and improvements in the quality of fuel may be 
    needed to make the Standards technologically feasible and otherwise 
    appropriate under the Act. As part of the focus on reducing 
    NOX, and in cooperation with the fuels industry, the 
    Signatories are committed to making improvements in diesel fuel (and 
    other fuels used in heavy-duty engines) as appropriate under the Act 
    to meet the 2004 Standards, taking into consideration costs and 
    other relevant factors. Such efforts may include evaluation of the 
    contribution of fuel parameters to heavy-duty engine emissions, 
    including a higher cetane number and lower levels of aromatics and 
    sulfur. The Signatories recognize fuel improvements are important 
    and may be essential in reaching low NOX levels in the most 
    efficient manner, considering costs and other factors. The 
    Signatories also recognize that any changes to both the 
    certification and commercial fuel specification would have to become 
    effective no later than October 2003 to ensure fuel availability at 
    the time the Standards take effect.
        3. Feasibility: To assess the progress of industry efforts to 
    meet the Standards set forth in this SOP and to assure the lowest 
    appropriate standards in 2004, in 1999 EPA shall review any 
    rulemaking adopting the Standards discussed herein by issuing a 
    notice providing the opportunity for public comment on whether or 
    not the Standards are technologically feasible and otherwise 
    appropriate under the CAA. After receiving public comment, EPA shall 
    take final Agency action on the review under Sec. 307 of the CAA, 
    and shall revise the rule if the Agency determines that the 
    Standards are not technologically feasible or are otherwise not 
    appropriate under the CAA. The evaluation will consider the status 
    of heavy-duty engine technology in that year and its projection to 
    2004. In addition, the evaluation will include an assessment of 
    whether any fuel improvements (see item #2) that are needed to 
    assist heavy-duty engines in complying with the Standards will be 
    available nationwide.
        In reviewing the rulemaking as set forth above, EPA shall review 
    the need, feasibility and cost of the Standards under the criteria 
    imposed on EPA by the Act, including, without limitation, the need 
    to provide engine manufacturers no less than four full model years 
    of lead-time. If EPA determines compliance with the Standards in 
    2004 is not technologically feasible or is otherwise not in 
    accordance with the Act, then the Administrator will adjust the 
    standard. If an adjustment is deemed necessary, the Standards for 
    2004 are not expected to be raised beyond a cap of: (1) 2.9 g/bhp-hr 
    NMHC+NOX and (2) 3.0 g/bhp-hr NMHC+NOX with a proportional 
    increase in the NMHC cap. However, if improvements to fuel quality 
    are needed but not made, the Standards are not expected to be raised 
    beyond a cap of: (1) 3.4 g/bhp-hr NMHC+NOX and (2) 3.5 g/bhp-hr 
    NMHC+NOX with a proportional increase in the NMHC cap.
        The Signatories shall meet periodically to provide updates on 
    their efforts and progress in complying with the SOP.
        4. California Standards: The California State Implementation 
    Plan (``SIP'') includes a proposed control measure to establish a 
    2.0 g/bhp-hr NOX emission standard for new engines used in on-
    highway trucks sold in California in 2002 and thereafter. Both EPA 
    and California recognize the benefits of harmonizing state and 
    federal regulations. California confirms its intent to notice a 
    public hearing to consider action to harmonize its regulations for 
    dynamometer-certified engines greater than 8,500 lbs. GVWR with the 
    federal regulations adopted under this SOP, provided such action 
    would not compromise California's obligations to comply with state 
    and federal law including the SIP. The Signatories recognize that 
    California regulations establishing separate emission standards and 
    test procedures for gasoline chassis-certified vehicles are not 
    affected by this SOP.
        5. Test Procedures: While there has been some discussion of 
    current test procedures for heavy-duty engines, the SOP and the 
    subsequent NPRM are premised on EPA not altering federal test 
    procedures. It is possible that the Agency may evaluate changes for 
    testing heavy-duty engines in the future, but it is recognized that 
    the SOP is made in the context of current test procedures. Further, 
    all Signatories recognize that any test cycle changes or additions 
    would likely complicate and delay industry's ability to research, 
    design, test, and produce engines that comply with the Standards by 
    2004. Any changes to test procedures used to determine compliance 
    with the Standards for purposes of EPA certification or enforcement 
    programs could also affect industry's ability to meet the Standards.
        6. Durability: All Signatories recognize that it is important 
    that emissions from cleaner heavy-duty engines be maintained 
    throughout the life of the engine. To meet this goal, the 
    Signatories will work to develop appropriate measures which ensure 
    that emission gains are maintained in-use.
        7. Averaging, Banking, and Trading Incentives: As part of this 
    SOP, EPA and CARB will work cooperatively with industry to develop 
    improved national averaging, banking, and trading (``AB&T'') 
    programs that will create more incentive for the early introduction 
    of cleaner engines. At a minimum, EPA will propose to modify the 
    existing AB&T program to eliminate any limitations on credit life 
    and to eliminate all credit discounts. The Signatories acknowledge 
    that an improved AB&T program may be critical in making the 
    Standards feasible in 2004, and would provide an incentive for early 
    introduction of cleaner technology.
        In addition, EPA shall solicit comments in the NPRM on the 
    merits of allowing cross-fuel, cross-subclass, and cross-category 
    (e.g. on-highway and nonroad) credit exchanges, to the extent 
    permitted under the Act.
        8. Scope: These standards will apply to all on-highway heavy-
    duty engines, including those operating on diesel, gasoline, or 
    alternative fuels or fuel blends. It is recognized that EPA and 
    California place a 
    
    [[Page 45604]]
    high priority on the need for additional nonroad heavy-duty engine 
    standards, and that additional nonroad heavy-duty engine standards 
    may be required. The Signatories intend to participate in 
    discussions with nonroad heavy-duty engine and equipment 
    manufacturers to develop a separate SOP by approximately October 
    1995 addressing emissions standards for heavy-duty nonroad engines.
        9. Stability: One of the key principles of the SOP is to provide 
    industry with increased certainty and stability for their business 
    planning. Without such certainty and stability, industry would not 
    commit to the enormous investment that the Standards will require. 
    And, without such certainty and stability, those investments might 
    never be recouped. EPA and California recognize the huge investment 
    that will be required of industry. Under the Act, the minimum period 
    of stability that EPA must provide for new on-highway heavy-duty 
    engine emissions standards is three years. However, EPA and 
    California acknowledge that under this SOP industry will be making a 
    commitment and investment that will require more than the minimum 
    period of stability.
        10. Research Agreement: The Signatories recognize the benefits 
    of a joint industry/government research program with the goal of 
    developing engine and fuel technologies which can meet and exceed 
    the standards for heavy-duty on-highway engines outlined in this 
    SOP. The Signatories will undertake development of a separate 
    research agreement with goals of reducing NOX emissions to 1.0 
    g/bhp-hr and PM emissions to 0.05 g/bhp-hr while maintaining 
    attributes of current on-highway diesel engines such as performance, 
    reliability, durability, safety, and efficiency. These 
    characteristics have allowed current diesel engines to serve as the 
    pillar of the international trucking industry. This research 
    agreement would include certain of the industry signatories below, 
    EPA, CARB, and other organizations, such as the U.S. Department of 
    Energy, as are approved by the participants.
    
        Signed July 11, 1995, Chicago, Illinois.
    Mary D. Nichols,
    U.S. Environmental Protection Agency.
    John D. Dunlap,
    California Air Resources Board.
    
    Members of the Engine Manufacturer Association
    
    Caterpillar, Inc.
    Cummins Engine Company
    Detroit Diesel Corporation
    Ford Motor Company
    General Motors Corporation
    Hino Motors, Ltd.
    Mack Trucks, Inc.
    Mitsubishi Motors America, Inc.
    Navistar International
    Volvo Truck Corporation
    Environmental Protection Agency (Mary D. Nichols)
    California Air Resources Board (John Dunlap)
    
    [FR Doc. 95-21525 Filed 8-30-95; 8:45 am]
    BILLING CODE 6560-50-P
    
    

Document Information

Published:
08/31/1995
Department:
Environmental Protection Agency
Entry Type:
Proposed Rule
Action:
Advance notice of proposed rule.
Document Number:
95-21525
Dates:
EPA requests comment on this ANPRM no later than October 2, 1995. Should a commenter miss the requested deadline, EPA will try to consider any comments that it receives prior to publication of the expected NPRM regarding additional highway heavy-duty engine emission controls. There will also be an opportunity to comment on any NPRM that EPA publishes.
Pages:
45580-45604 (25 pages)
Docket Numbers:
AMS-FRL-5288-4
RINs:
2060-AF76: Control of Emissions of Air Pollution From Highway Heavy-Duty Engines and Diesel Engines
RIN Links:
https://www.federalregister.gov/regulations/2060-AF76/control-of-emissions-of-air-pollution-from-highway-heavy-duty-engines-and-diesel-engines
PDF File:
95-21525.pdf
CFR: (3)
40 CFR 80
40 CFR 86
40 CFR 89