[Federal Register: October 5, 2001 (Volume 66, Number 194)]
[Proposed Rules]               
[Page 51097-51146]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05oc01-53]                         
 

[[Page 51097]]

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Part II

Environmental Protection Agency

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40 CFR Part 89, 90, 91, etc.

Control of Emissions From Nonroad Large Spark Ignition Engines and 
Recreational Engines (Marine and Land-Based); Proposed Rule

[[Page 51098]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 89, 90, 91, 94, 1048, 1051, 1065, and 1068

[AMS-FRL-7058-8]
RIN 2060-AI11

 
Control of Emissions From Nonroad Large Spark Ignition Engines 
and Recreational Engines (Marine and Land-Based)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

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SUMMARY: In this action, we are proposing emission standards for 
several groups of nonroad engines that cause or contribute to air 
pollution but that have yet to be regulated by EPA. These engines 
include large spark-ignition engines such as those used in forklifts 
and airport tugs; recreational vehicles using spark-ignition engines 
such as off-highway motorcycles, all-terrain vehicles, and snowmobiles; 
and recreational marine diesel engines. Nationwide, engines and 
vehicles in these various categories contribute to ozone, CO, and PM 
nonattainment. These pollutants cause a range of adverse health 
effects, especially in terms of respiratory impairment and related 
illnesses. The proposed standards will help states achieve air quality 
standards. In addition, the proposed standards will help reduce acute 
exposure to CO, air toxics, and PM for operators and other people close 
to the emission source. They will also help address other environmental 
problems, such as visibility impairment in our national parks.
    We expect that manufacturers will be able to maintain or even 
improve the performance of their products when producing engines and 
equipment meeting the proposed standards. In fact, many engines will 
substantially reduce their fuel consumption, partially or completely 
offsetting any costs associated with the emission standards. Overall, 
we estimate the gasoline-equivalent fuel savings associated with the 
anticipated changes in technology resulting from this rule would be 
about 730 million gallons per year once the program is fully phased in. 
The proposal also has several provisions to address the unique 
limitations of small-volume manufacturers.

DATES: Comments: Send written comments on this proposed rule by 
December 19, 2001. See Section X.B for more information about written 
comments.
    Hearings: We will hold a public hearing in the Washington, DC area 
on October 24. We will hold a second public hearing on October 30 in 
Denver, CO. See Section X.B for more information about public hearings.

ADDRESSES: Comments: You may send written comments in paper form or by 
e-mail. We must receive them by the date indicated under DATES above. 
Send paper copies of written comments (in duplicate if possible) to the 
contact person listed below. You may also submit comments via e-mail to 
``NRANPRM@epa.gov.'' In your correspondence, refer to Docket A-2000-01. 
See Section X.B for more information on comment procedures.
    Docket: EPA's Air Docket makes materials related to this rulemaking 
available for review in Public Docket No. A-2000-01 at the following 
address: U.S. Environmental Protection Agency (EPA), Air Docket (6102), 
Room M-1500 (on the ground floor in Waterside Mall), 401 M Street, SW., 
Washington, DC 20460 between 8 a.m. to 5:30 p.m., Monday through 
Friday, except on government holidays. You can reach the Air Docket by 
telephone at (202) 260-7548, and by facsimile (202) 260-4400. We may 
charge a reasonable fee for copying docket materials, as provided in 40 
CFR part 2.
    Hearings: We will hold a public hearing on October 24, 2001 at 
Washington Dulles Airport Marriott, Dulles, VA 20166 (703-471-9500). We 
will hold a second public hearing October 30, 2001 at Doubletree Hotel, 
3203 Quebec Street, Denver, CO 80207 (303-321-3333). If you want to 
testify at a hearing, notify the contact person listed below at least 
ten days before the date of the hearing. See Section X.B for more 
information on the public-hearing procedures.

FOR FURTHER INFORMATION CONTACT: Margaret Borushko, U.S. EPA, National 
Vehicle and Fuels Emission Laboratory, 2000 Traverwood, Ann Arbor, MI 
48105; Telephone (734) 214-4334; Fax: (734) 214-4816; E-mail: 
borushko.margaret@epa.gov.

SUPPLEMENTARY INFORMATION:

Regulated Entities

    This proposed action would affect companies that manufacture or 
introduce into commerce any of the engines or vehicles that would be 
subject to the proposed standards. These include: spark-ignition 
industrial engines such as those used in forklifts and airport tugs; 
recreational vehicles such as off-highway motorcycles, all-terrain 
vehicles, and snowmobiles; and recreational marine diesel engines. This 
proposed action would also affect companies buying engines for 
installation in nonroad equipment. There are also proposed requirements 
that apply to those who rebuild any of the affected nonroad engines. 
Regulated categories and entities include:

------------------------------------------------------------------------
                            NAICS                Examples of potentially
        Category           codes a    SIC codes     regulated entities
------------------------------------------b-----------------------------
Industry...............      333618        3519  Manufacturers of new
                                                  nonroad SI engines,
                                                  new marine engines.
      Do...............      333111        3523  Manufacturers of farm
                                                  equipment.
      Do...............      333112        3531  Manufacturers of
                                                  construction
                                                  equipment,
                                                  recreational marine
                                                  vessels.
      Do...............      333924        3537  Manufacturers of
                                                  industrial trucks.
      Do...............      811310        7699  Engine repair and
                                                  maintenance.
      Do...............      336991  ..........  Motorcycles and
                                                  motorcycle parts
                                                  manufacturers.
      Do...............      336999  ..........  Snowmobiles and all-
                                                  terrain vehicle
                                                  manufacturers.
      Do...............      421110  ..........  Independent Commercial
                                                  Importers of Vehicles
                                                  and Parts.
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a North American Industry Classification System (NAICS).
b Standard Industrial Classification (SIC) system code.

    This list is not intended to be exhaustive, but rather provides a 
guide regarding entities likely to be regulated by this action. To 
determine whether particular activities may be regulated by this 
action, you should carefully examine the proposed regulations. You may 
direct questions regarding the applicability of this action to the 
person listed in FOR FURTHER INFORMATION CONTACT.

[[Page 51099]]

Obtaining Electronic Copies of the Regulatory Documents

    The preamble, regulatory language, Draft Regulatory Support 
Document, and other rule documents are also available electronically 
from the EPA Internet Web site. This service is free of charge, except 
for any cost incurred for internet connectivity. The electronic version 
of this proposed rule is made available on the day of publication on 
the primary web site listed below. The EPA Office of Transportation and 
Air Quality also publishes Federal Register notices and related 
documents on the secondary web site listed below.

1. http://www.epa.gov/docs/fedrgstr/EPA-AIR/ (either select desired 
date or use Search feature)
2. http://www.epa.gov/otaq/ (look in What's New or under the specific 
rulemaking topic)

    Please note that due to differences between the software used to 
develop the documents and the software into which the document may be 
downloaded, format changes may occur.

Table of Contents

I. Introduction
    A. Overview
    B. How Is This Document Organized?
    C. What Categories of Vehicles and Engines Are Covered in This 
Proposal?
    D. What Requirements Are We Proposing?
    E. Why Is EPA Taking This Action?
    F. Putting This Proposal Into Perspective
II. Public Health and Welfare Effects of Emissions From Covered 
Engines
    A. Background
    B. What Are the Public Health and Welfare Effects Associated 
With Emissions From Nonroad Engines Subject to the Proposed 
Standards?
    C. What Is the Inventory Contribution From the Nonroad Engines 
and Vehicles That Would Be Subject to This Proposal?
    D. Regional and Local-Scale Public Health and Welfare Effects
III. Nonroad: General Concepts
    A. Scope of Application
    B. Emission Standards and Testing
    C. Demonstrating Compliance
    D. Other Concepts
IV. Large SI Engines
    A. Overview
    B. Large SI Engines Covered by This Proposal
    C. Proposed Standards
    D. Proposed Testing Requirements and Supplemental Emission 
Standards
    E. Special Compliance Provisions
    F. Technological Feasibility of the Standards
V. Recreational Marine Diesel Engines
    A. Overview
    B. Engines Covered by This Proposal
    C. Proposed Standards for Marine Diesel Engines
    D. Proposed Testing Requirements
    E. Special Compliance Provisions
    F. Technical Amendments
    G. Technological Feasibility
VI. Recreational Vehicles and Engines
    A. Overview
    B. Engines Covered by this Proposal
    C . Proposed Standards
    D. Proposed Testing Requirements
    E. Special Compliance Provisions
    F. Technological Feasibility of the Standards
VII. General Nonroad Compliance Provisions
    A. Miscellaneous Provisions (Part 1068, Subpart A)
    B. Prohibited Acts and Related Requirements (Part 1068, Subpart 
B)
    C. Exemptions (Part 1068, Subpart C)
    D. Imports (Part 1068, Subpart D)
    E. Selective Enforcement Audit (Part 1068, Subpart E)
    F. Defect Reporting and Recall (Part 1068, Subpart F)
    G. Public Hearings (Part 1068, Subpart G)
VIII. General Test Procedures
    A. General Provisions
    B. Laboratory Testing Equipment
    C. Laboratory Testing Procedures
IX. Projected Impacts
    A. Environmental Impact
    B. Economic Impact
    C. Cost per Ton of Emissions Reduced
    D. Additional Benefits
X. Public Participation
    A. How Do I Submit Comments?
    B. Will There Be a Public Hearing?
XI. Administrative Requirements
    A. Administrative Designation and Regulatory Analysis (Executive 
Order 12866)
    B. Regulatory Flexibility Act
    C. Paperwork Reduction Act
    D. Intergovernmental Relations
    E. National Technology Transfer and Advancement Act
    F. Protection of Children (Executive Order 13045)
    G. Federalism (Executive Order 13132)
    H. Energy Effects (Executive Order 13211)
    I. Plain Language

I. Introduction

A. Overview

    Air pollution is a serious threat to the health and well-being of 
millions of Americans and imposes a large burden on the U.S. economy. 
Ground-level ozone, carbon monoxide, and particulate matter are linked 
to potentially serious respiratory health problems, especially 
respiratory effects and environmental degradation, including visibility 
impairment in our precious national parks. Over the past quarter 
century, state and federal representatives have established emission-
control programs that significantly reduce emissions from individual 
sources. Many of these sources now pollute at only a small fraction of 
their precontrol rates. This proposal further addresses these air-
pollution concerns by proposing national emission standards for several 
types of nonroad engines and vehicles that are currently unregulated. 
These include industrial spark-ignition engines such as those used in 
forklifts and airport tugs; recreational vehicles such as off-highway 
motorcycles, all-terrain vehicles, and snowmobiles; and recreational 
marine diesel engines.\1\ The proposed standards are a continuation of 
the process of establishing standards for nonroad engines and vehicles, 
as required by Clean Air Act section 213(a)(3). All the nonroad engines 
subject to this proposal are still unregulated emission sources.
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    \1\ Diesel-cycle engines, referred to simply as ``diesel 
engines'' in this document, may also be referred to as compression-
ignition (or CI) engines. These engines typically operate on diesel 
fuel, but other fuels may also be used. Otto-cycle engines (referred 
to here as spark-ignition or SI engines) typically operate on 
gasoline, liquefied petroleum gas, or natural gas.
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    Nationwide, these engines are a significant source of mobile-source 
air pollution. They currently account for about 13 percent of mobile-
source hydrocarbon (HC) emissions, 6 percent of mobile-source carbon 
monoxide (CO) emissions, 3 percent of mobile-source oxides of nitrogen 
( NOX) emissions, and 1 percent of mobile-source particulate 
matter (PM) emissions.\2\ The proposed standards will reduce exposure 
to these emissions and help avoid a range of adverse health effects 
associated with ambient ozone, CO, and PM levels, especially in terms 
of respiratory impairment and related illnesses. In addition, the 
proposed standards will help reduce acute exposure to CO, air toxics, 
and PM for persons who operate or who work with or are otherwise active 
in close proximity to these engines. They will also help address other 
environmental problems associated with these engines, such as 
visibility impairment in our national parks and other wilderness areas 
where recreational vehicles and marine engines are often used.
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    \2\ While we characterize emissions of hydrocarbons, this can be 
used as a surrogate for volatile organic compounds (VOC), which is a 
broader group of compounds.
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    This proposal follows a final finding published on December 7, 2000 
(65 FR 76790). Under this finding, EPA found that industrial spark-
ignition (SI) engines rated above 19 kilowatts (kW), as well as all 
land-based recreational nonroad spark-ignition engines, cause or 
contribute to air quality nonattainment in more than one ozone or 
carbon monoxide (CO) nonattainment area. We also found that particulate 
matter (PM) emissions from these engines cause or contribute to air 
pollution that may reasonably be anticipated to endanger public health 
or welfare.
    This proposal also follows EPA's Advance Notice of Proposed

[[Page 51100]]

Rulemaking (ANRPM) published on December 7, 2000 (65 FR 76797). In that 
Advance Notice, we provided an initial overview of possible regulatory 
strategies for the nonroad vehicles and engines and invited early input 
to the process of developing standards. We received comments on the 
Advance Notice from a wide variety of stakeholders, including the 
engine industry, the equipment industry, various governmental bodies, 
environmental groups, and the general public. The Advance Notice, the 
related comments, and other new information provide the framework for 
this proposal.

B. How Is This Document Organized?

    This proposal covers engines and vehicles that vary in design and 
use, and many readers may be interested in only one or two of the 
applications. For the purpose of this proposal, we have chosen to group 
engines by common application (e.g., recreational land-based engines, 
marine engines, large spark-ignition engines used in commercial 
applications). We have attempted to organize the document in a way that 
allows each reader to focus on the applications of particular interest. 
The Air Quality discussion in Section II is general in nature, however, 
and applies to all the categories covered by this proposal.
    The next four sections contain our proposal for the nonroad engines 
that are the subject of this action. Sections III contains some general 
concepts that are relevant to all of the nonroad engines covered by 
this proposal. Section IV through VI present information specific to 
each of the nonroad applications covered by the proposal, including 
standards, effective dates, testing information, and other specific 
requirements.
    Sections VII and VIII describe a wide range of compliance and 
testing provisions that apply generally to engines and vehicles from 
all the nonroad engine and vehicle categories included in this 
proposal. Several of these provisions apply not only to manufacturers, 
but also to equipment manufacturers installing certified engines, 
remanufacturing facilities, operators, and others. Therefore, all 
affected parties should read the information contained in this section.
    Section IX summarizes the projected impacts and a discussion of the 
benefits of this proposal. Finally, Sections X and XI contain 
information about public participation, how we satisfied our 
administrative requirements, and the statutory provisions and legal 
authority for this proposal.
    The remainder of this Section I summarizes important background 
information about this proposal, including the engines covered, the 
proposed standards, and why we are proposing them.

C. What Categories of Vehicles and Engines Are Covered in This 
Proposal?

    This proposal presents regulatory strategies for new nonroad 
vehicles and engines that have yet to be regulated under EPA's nonroad 
engine programs. This proposal covers the following engines:
     Land-based spark-ignition recreational engines, including 
those used in snowmobiles, off-highway motorcycles, and all-terrain 
vehicles. For the purpose of this proposal, we are calling this group 
of engines ``recreational vehicles,'' even though all-terrain vehicles 
can be used for commercial purposes.
     Land-based spark-ignition engines rated over 19 kW, 
including engines used in forklifts, generators, airport tugs, and 
various farm, construction, and industrial equipment. This category 
also includes auxiliary marine engines, but does not include engines 
used in recreational vehicles. For the purpose of this proposal, we are 
calling this group of engines ``Large SI engines.''
     Recreational marine diesel engines.
    This proposal covers new engines that are used in the United 
States, whether they are made domestically or imported.\3\ A more 
detailed discussion of the meaning of the terms ``new,'' ``imported,'' 
as well as other terms that help define the scope of application of 
this proposal, is contained in Section III of this preamble.
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    \3\ For this proposal, we consider the United States to include 
the States, the District of Columbia, the Commonwealth of Puerto 
Rico, the Commonwealth of the Northern Mariana Islands, Guam, 
American Samoa, the U.S. Virgin Islands, and the Trust Territory of 
the Pacific Islands.
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    We intended to include in this proposal emission standards for two 
additional vehicle categories: new exhaust emission standards for 
highway motorcycles and new evaporative emission standards for marine 
vessels powered by spark-ignition engines. Proposals for these two 
categories are not included in the September 14 deadline mandated by 
the courts, as is the case for the remaining contents that appear in 
today's proposed rule. We are committed to issue proposals regarding 
these categories within the next two to three months. Interested 
parties will have an opportunity to comment on issues associated with 
the proposed standards for these two categories during the public 
review period that will begin after a subsequent proposal or proposals 
are issued.

D. What Requirements Are We Proposing?

    The fundamental requirement for engines under Clean Air Act section 
213 is to meet EPA's emission standards. The Act requires that 
standards achieve the greatest degree of emission reduction achievable 
through the application of technology that will be available, giving 
appropriate consideration to cost, noise, energy, and safety factors. 
Other requirements such as applying for certification, labeling 
engines, and meeting warranty requirements define a process for 
implementing the proposed program in an effective way.
    With regard to Large SI engines, we are proposing a two-phase 
program. The first phase of the standards, to go into effect in 2004, 
are the same as those recently adopted by the California Air Resources 
Board. These standards will reduce combined HC and NOX 
emissions by nearly 75 percent, based on a steady-state test. In 2007, 
we propose to supplement these standards by setting limits that would 
require optimizing the same technologies but would be based on a 
transient test cycle. New requirements for evaporative emissions and 
engine diagnostics would also start in 2007.
    For recreational vehicles, we are proposing emission standards for 
snowmobiles separately from off-highway motorcycles and all-terrain 
vehicles. For snowmobiles, we are proposing a first phase of standards 
for HC and CO emissions based on the use of clean carburetion or 2-
stroke electronic fuel injection (EFI) technology, and a second phase 
of emission standards for snowmobiles that would involve significant 
use of direct fuel injection 2-stroke technology, as well as possible 
limited conversion to 4-stroke engines. For off highway motorcycles and 
all-terrain vehicles, we are proposing standards that would result in a 
50-percent reduction and is based mainly on moving these engines from 
2-stroke to 4-stroke technology. In addition, we are proposing a second 
phase of standards for all-terrain vehicles that would require some 
catalyst use.
    We are also proposing voluntary Blue Sky Series emission standards 
for recreational marine diesel engines and industrial spark-ignition 
engines. Blue Sky Series emission standards are intended to encourage 
the introduction and more widespread use of low-emission technologies. 
Manufacturers could be motivated to exceed emission

[[Page 51101]]

requirements either to gain early experience with certain technologies 
or as a response to market demand or local government programs. For 
recreational vehicles, we are proposing separate voluntary standards 
based more on providing consumers with an option of buying low-emission 
models.

E. Why Is EPA Taking This Action?

    There are important public health and welfare reasons supporting 
the standards proposed in this document. As described in Section II.B, 
these engines contribute to air pollution which causes public health 
and welfare problems. Emissions from these engines contribute to ground 
level ozone and ambient CO and PM levels. Exposure to ground level 
ozone, CO, and PM can cause serious respiratory problems. These 
emissions also contribute to other serious environmental problems, 
including visibility impairment.
    We believe existing technology that can be applied to these engines 
would reduce emissions of these harmful pollutants. Manufacturers can 
reduce 2-stroke engine emissions by improving fuel management and 
calibration. In addition, many of the existing 2-stroke engines in 
these categories can be converted to 4-stroke technology. Finally, 
there are modifications that can be made to 4-stroke engines, often 
short of requiring catalysts, that can reduce emissions even further.

F. Putting This Proposal Into Perspective

    This proposal should be considered in the broader context of EPA's 
nonroad emission-control programs; state-level programs, particularly 
in California; and international efforts. Each of these are described 
in more detail below.
1. EPA's Nonroad Emission-Control Programs
    a. EPA's nonroad process. Clean Air Act section 213(a)(1) directs 
us to study emissions from nonroad engines and vehicles to determine, 
among other things, whether these emissions ``cause, or significantly 
contribute to, air pollution that may reasonably be anticipated to 
endanger public health or welfare.'' Section 213(a)(2) further required 
us to determine whether emissions of CO, VOC, and NOX from 
all nonroad engines significantly contribute to ozone or CO emissions 
in more than one nonattainment area. If we determine that emissions 
from all nonroad engines were significant contributors, section 
213(a)(3) then requires us to establish emission standards for classes 
or categories of new nonroad engines and vehicles that in our judgment 
cause or contribute to such pollution. We may also set emission 
standards under section 213(a)(4) regulating any other emissions from 
nonroad engines that we find contribute significantly to air pollution.
    We completed the Nonroad Engine and Vehicle Emission Study, 
required by Clean Air Act section 213(a)(1), in November 1991.\4\ On 
June 17, 1994, we made an affirmative determination under section 
213(a)(2) that nonroad emissions are significant contributors to ozone 
or CO in more than one nonattainment area. We also determined that 
these engines make a significant contribution to PM and smoke emissions 
that may reasonably be anticipated to endanger public health or 
welfare. In the same document, we set a first phase of emission 
standards (now referred to as Tier 1 standards) for land-based nonroad 
diesel engines rated at or above 37 kW. We recently added a more 
stringent set of Tier 2 and Tier 3 emission levels for new land-based 
nonroad diesel engines at or above 37 kW and adopted Tier 1 standards 
for land-based nonroad diesel engines less than 37 kW. Our other 
emission-control programs for nonroad engines are listed in Table I.F-
1. This proposal takes another step toward the comprehensive nonroad 
engine emission-control strategy envisioned in the Act by proposing an 
emission-control program for the remaining unregulated nonroad engines.
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    \4\ This study is available in docket A-92-28.

                              Table I.F-1.--EPA's Nonroad Emission-Control Programs
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           Engine category                    Final rulemaking                           Date
----------------------------------------------------------------------------------------------------------------
Land-based diesel engines   56 FR 31306                    June 17, 1994.
 37 kW--Tier 1.
Spark-ignition engines  19  60 FR 34581                    July 3, 1995.
 kW--Phase 1.
Spark-ignition marine................  61 FR 52088                    October 4, 1996.
Locomotives..........................  63 FR 18978                    April 16, 1998.
Land-based diesel engines--Tier 1 and  63 FR 56968                    October 23, 1998.
 Tier 2 for engines  37 kW.
      --Tier 2 and Tier 3 for engines
  37 kW
Commercial marine diesel.............  64 FR 73300                    December 29, 1999.
Spark-ignition engines  19  64 FR 15208                    March 30, 1999.
 kW (Non-handheld)--Phase 2.
Spark-ignition engines  19  65 FR 24268                    April 25, 2000.
 kW (Handheld)--Phase 2.
----------------------------------------------------------------------------------------------------------------

    b. National standards for marine engines. In the October 1996 final 
rule for spark-ignition marine engines, we set standards only for 
outboard and personal watercraft engines. We decided not to finalize 
emission standards for sterndrive or inboard marine engines at that 
time. Uncontrolled emission levels from sterndrive and inboard marine 
engines were already significantly lower than the outboard and personal 
watercraft engines. We did, however, leave open the possibility of 
revisiting the need for emission standards for sterndrive and inboard 
engines in the future.
    In December 1999, we published emission standards for commercial 
marine diesel engines. To allow more time to evaluate the potential 
impact of the proposed emission limits on the recreational vessel 
industry, we did not include recreational propulsion marine diesel 
engines in that rulemaking.
    c. National standards for land-based spark-ignition engines. The 
standards we have set to date for land-based, spark-ignition nonroad 
engines apply to engines typically used in lawn and garden 
applications. In adopting these emission standards, we decided not to 
include engines rated over 19 kW or any engines used in recreational 
vehicles. The proposed emission-control program in this document 
addresses these remaining unregulated engines.
2. State Initiatives
    Under Clean Air Act section 209, California has the authority to 
regulate emissions from new motor vehicles and new motor vehicle 
engines. California may also regulate emissions from nonroad engines, 
with the exception of

[[Page 51102]]

new engines used in locomotives and new engines used in farm and 
construction equipment rated under 130 kW.\5\ So far, the California 
Air Resources Board (California ARB) has adopted requirements for four 
groups of nonroad engines: (1) Diesel- and Otto-cycle small off-road 
engines rated under 19 kW; (2) new land-based nonroad diesel engines 
rated over 130 kW; (3) land-based nonroad recreational engines, 
including all-terrain vehicles, snowmobiles, off-highway motorcycles, 
go-carts, and other similar vehicles; and (4) new nonroad SI engines 
rated over 19 kW. They have approved a voluntary registration and 
control program for existing portable equipment.
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    \5\ The Clean Air Act limits the role states may play in 
regulating emissions from new motor vehicles and nonroad engines. 
California is permitted to establish emission standards for new 
motor vehicles and most nonroad engines; other states may adopt 
California's programs (sections 209 and 177 of the Act).
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    Other states may adopt emission standards set by California ARB, 
but are otherwise preempted from setting emission standards for new 
engines or vehicles. In contrast, there is generally no federal 
preemption of state initiatives related to the way individuals use 
individual engines or vehicles.
    a. Industrial SI engines. California ARB in 1998 adopted 
requirements that apply to new nonroad engines rated over 25 hp 
produced for California starting in 2001. These standards phase in over 
three years, during which manufacturers show only that engines meet the 
standards before they start in service. Beginning in 2004, the 
standards apply to 100 percent of engines sold in California, including 
a requirement to show that an engine meets emission standards 
throughout its useful life. As described above, these standards do not 
apply to engines under 130 kW used in farm or construction equipment. 
Texas has adopted the California ARB emission standards statewide 
starting in 2004.
    b. Off-highway motorcycles and all-terrain vehicles. California 
established standards for off-highway motorcycles and all-terrain 
vehicles which took effect in January 1997 (1999 for vehicles with 
engines of 90 cc or less). The standards are 1.2 g/km HC and 15.0 g/km 
CO and are based on the highway motorcycle chassis test procedures. 
Manufacturers may certify all-terrain vehicles to optional standards, 
which are based on the utility engine test procedure.\6\ These 
standards are 12 g/hp-hr HC+NOX and 300 g/hp-hr CO, for all-
terrain vehicles with engine displacements less than 225 cubic 
centimeters (cc) and 10 g/hp-hr NC+NOX and 300 g/hp-hr CO, 
for all-terrain vehicles with engine displacement greater than 225 cc. 
The utility engine test procedure is the procedure over which Small SI 
engines are tested. The stringency level of the standards was based on 
the emissions performance of 4-stroke engines and advanced 2-stroke 
engines equipped with a catalytic converter. California anticipated 
that the standards would be met initially through the use of high 
performance 4-stroke engines.
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    \6\ Notice to Off-Highway Recreational Vehicle Manufacturers and 
All Other Interested Parties Regarding Alternate Emission Standards 
for All-Terrain Vehicles, Mail Out #95-16, April 28, 1995, 
California ARB (Docket A-2000-01, document II-D-06).
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    California revisited the program in the 1997 time frame because a 
lack of certified product from manufacturers was reportedly creating 
economic hardship for dealerships. The number of certified off-highway 
motorcycle models was particularly inadequate.\7\ In 1998, California 
revised the program, allowing the use of uncertified products in off-
highway vehicle recreation areas with regional/seasonal use 
restrictions. Currently, noncomplying vehicles can be legally sold in 
California and used in attainment areas year-round and in nonattainment 
areas during months when exceedances of the state ozone standard are 
not expected. For enforcement purposes, certified and uncertified 
products are identified respectively with green and red stickers. Only 
about one-third of off-highway motorcycles sold in California are 
certified.
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    \7\ Initial Statement of Reasons, Public Hearing to Consider 
Amendments to the California Regulations for New 1997 and Later Off-
highway Recreational Vehicles and Engines, California ARB, October 
23, 1998 (Docket A-2000-01, II-D-08).
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3. Actions in Other Countries
    a. European action--Recreational Marine Engines. The European 
Commission has proposed emission standards for recreational marine 
engines, including both diesel and gasoline engines. These requirements 
would apply to all new engines sold in member countries. The numerical 
emission standards for recreational diesel marine engines, shown in 
Table I.F-2, consist of the Annex VI NOX standard for small 
marine diesel engines, the rough equivalent of Nonroad Diesel Tier 1 
emission standards for HC and CO. Emission testing is to be conducted 
using the ISO D2 duty cycle for constant-speed engines and the ISO E5 
duty cycle for all other engines. Table I.F-2 also presents average 
baseline emissions based on data that we have collected. These data are 
presented in Chapter 4 of the Draft Regulatory Support Document. We 
have received comment that we should apply these standards in the U.S., 
but the proposed European emission standards for recreational marine 
diesel engines may not result in a decrease in emissions, and may even 
allow an increase in emissions from engines operated in the U.S.

   Table I.F-2.--Proposed European Emission Standards for Recreational
                          Marine Diesel Engines
------------------------------------------------------------------------
                                                     Emission   Baseline
                                                     standard  emissions
                     Pollutant                       (g/k W-    (g/k W-
                                                       hr)        hr)
------------------------------------------------------------------------
NOX...............................................        9.8        8.9
PM................................................        1.4        0.2
HC................................................    \a\ 1.5        0.3
CO................................................        5.0       1.3
------------------------------------------------------------------------
\a\ Increases slightly with increasing engine power rating.

    b. International Maritime Organization--CI Marine Engines. In 
response to growing international concern about air pollution and in 
recognition of the highly international nature of maritime 
transportation, the International Maritime Organization developed a 
program to reduce NOX and SOx emissions from marine vessels. 
No restrictions on PM, HC, or CO emissions were considered. The 
NOX provisions, contained in Regulation 13 of Annex VI to 
the International Convention on the Prevention of Pollution from Ships 
(MARPOL 73/78), specify that each diesel engine with a power output of 
more than 130 kW installed on a ship constructed on or after January 1, 
2000, or that undergoes a major conversion on or after January 1, 2000, 
must meet the NOX emission standards in Table I.F-3.\8\ The 
Annex does not distinguish between marine diesel engines installed on 
recreational or commercial vessels; all marine diesel engines above 130 
kW would be subject to the standards regardless of their use.
---------------------------------------------------------------------------

    \8\ Additional information about the MARPOL Annex VI 
NOX standards can be found in the documents for our 
commercial marine diesel standards, which can be found on our 
website (http://www.epa.gov/otaq/marine.htm). That website also 
contains facts sheets and other information about the Annex.

               Table I.F-3.--MARPOL Annex VI NOX Standards
------------------------------------------------------------------------
                                                             NOX  (g/kW-
           Engine speed  (n = engine speed, rpm)                 hr)
------------------------------------------------------------------------
n 130 rpm..................................................         17.0
130 rpmn2000 rpm................................   45*n(-0.2)

[[Page 51103]]

n  2000.........................................          9.8
------------------------------------------------------------------------

    After several years of negotiation, the Member States of the 
International Maritime Organization adopted a final version of Annex VI 
on September 26, 1997. As stipulated in Article 6 of the Agreement, the 
Annex will go into force when fifteen States, the combined merchant 
fleets of which constitute not less than 50 percent of the gross 
tonnage of the world's merchant shipping, have ratified it. As of 
today, three countries have ratified the Annex (Norway, Sweden, 
Singapore), representing about 7 percent of the world fleet.
    Pending entry into force, ship owners and vessel manufacturers are 
expected to install compliant engines on relevant ships beginning with 
the date specified in Regulation 13, January 1, 2000. In addition, ship 
owners are expected to bring existing engines into compliance if the 
engines undergo a major conversion on or after that date.\9\ As defined 
in Regulation 13 of Annex VI, a major conversion is defined to include 
those situations when the engine is replaced by a new engine, it is 
substantially modified, or its maximum continuous rating is increased 
by more than 10 percent. To facilitate this process, and to allow 
engine manufacturers to certify their engines before the Annex goes 
into force, we set up a process for manufacturers to obtain a Statement 
of Voluntary Compliance.\10\ This document will be exchangeable for an 
Engine International Air Pollution Prevention (EIAPP) certificate once 
the Annex goes into effect for the United States.
---------------------------------------------------------------------------

    \9\ As defined in Regulation 13 of Annex VI, a major conversion 
means the engine is replaced by a new engine, it is substantially 
modified, or its maximum continuous rating is increased by more than 
10 percent.
    \10\ For more information about our voluntary certification 
program, see ``guidance for Certifying to MARPOL Annex VI,'' VPCD-
99-02. This letter is available on our website: http://www.epa.gov/
otaq/regs/nonroad/marine/ci/imolettr.pdf.
---------------------------------------------------------------------------

II. Public Health and Welfare Effects of Emissions From Covered 
Engines

A. Background

    This proposal contains regulatory strategies for three sets of new 
nonroad vehicles and engines that cause or contribute to air pollution 
but that have not been regulated under EPA's nonroad engine programs. 
The three sets of nonroad vehicles and engines are:
     Large Industrial Spark Ignition Engines. These are spark-
ignition nonroad engines rated over 19 kW used in commercial 
applications. These include engines used in forklifts, electric 
generators, airport tugs, and a variety of other construction, farm, 
and industrial equipment. Many of these engines, such as those used in 
farm and construction equipment, are operated outdoors, predominantly 
during warmer weather and often in or near heavily-populated urban 
areas where they contribute to ozone formation and ambient CO and PM 
levels. These engines are also often operated in factories, warehouses, 
and large retail outlets throughout the year, where they contribute to 
high exposure levels to personnel who work with or near this equipment 
as well as to ozone formation and ambient CO and PM levels. For the 
purpose of this proposal, we are calling these ``Large SI engines.''
     Nonroad Spark-Ignition Recreational Engines. These are 
spark-ignition nonroad engines used primarily in recreational 
applications. These include off-highway motorcycles, all-terrain-
vehicles and snowmobiles. Some of these engines, particularly those 
used on all-terrain vehicles, are increasingly used for commercial 
purposes within urban areas, especially for mowing lawns and hauling 
loads. These vehicles are typically used in suburban and rural areas, 
where they contribute to ozone formation and ambient CO, and PM levels. 
All these vehicles, and snowmobiles in particular, contribute to 
visibility impairment problems in our national and state parks. For the 
purpose of this proposal, we are calling this group of engines 
``recreational vehicles.''
     Marine Engines. These are marine diesel engines that are 
used on recreational vessels such as yachts, cruisers, and other types 
of pleasure craft. Recreational marine engines are primarily used in 
warm weather and therefore contribute to ozone formation and PM levels, 
especially in marinas, which are often located in nonattainment areas.
    Nationwide, these engines and vehicles are a significant source of 
mobile-source air pollution. As described in Section II.C, below, they 
currently account for about 13 percent of national mobile-source HC 
emissions, 6 percent of mobile-source CO emissions, 3 percent of 
mobile-source NOX emissions, and 1 percent of mobile-source 
PM emissions. Recreational vehicles by themselves account for nearly 10 
percent of national mobile-source HC emissions and about 3 percent of 
national mobile-source CO emissions. Within national parks, snowmobiles 
are significant contributors to ambient concentrations of fine 
particulate matter, a leading component of visibility impairment. By 
reducing these emissions, the proposed standards would provide 
assistance to states facing ozone and CO air quality problems, which 
can cause a range of adverse health effects, especially in terms of 
respiratory impairment and related illnesses. States are required to 
develop plans to address visibility impairment in national parks, and 
the reductions proposed in this rule would assist states in those 
efforts.
    In addition, the proposed standards would help reduce acute 
exposure to CO and air toxics for forklift operators, snowmobile users, 
national and state park attendants, and other people who may be at 
particular risk because they operate or work or are otherwise active 
for long periods of time in close proximity to this equipment. 
Emissions from these vehicles and equipment can be very high on a per 
engine basis. In addition, the equipment (e.g., forklifts) is often 
used in enclosed areas. Similarly, exposure can be intensified for 
snowmobile riders who follow a group of other rides along a trail, 
since those riders are exposed to the emissions of all the other 
snowmobiles riding ahead. As summarized below and explained in greater 
detail in the Draft Regulatory Support Document for this proposal, CO 
emissions have been directly associated with cardisvascular and other 
health problems, and many types of hydrocarbons are also air toxics.
    The standards proposed in this document would require the use of 
cleaner emission-control technologies. For Large SI engines, we are 
proposing a two-phase program that will take fuel effects into account. 
The first phase consists of one set of standards that would apply to 
all engines regardless of fuel (i.e., gasoline, LPG, CNG). These 
standards are identical to those recently adopted by California Air 
Resources Board (CARB) and are based on a steady-state test. The second 
phase of standards is more stringent than the California standards. The 
numerical limits differ depending on fuel type and would require 
optimizing the same emission-control technologies used in Phase 1 but 
would be based on a transient duty test cycle. These standards would 
also include new requirements for evaporative emissions and engine 
diagnostics.
    For marine engines, we are proposing to set new standards that 
would require recreational diesel marine engines to adopt the emission-
control technology

[[Page 51104]]

that will be in use on commercial diesel marine engines.
    For nonroad recreational vehicles, we are proposing standards that 
would require snowmobiles to use cleaner 2-stroke technologies (e.g., 
clean carburetion, electronic fuel injection). For off-highway 
motorcycles and all-terrain vehicles, we are proposing standards that 
would effectively require manufacturers to use more 4-stroke technology 
for most engines. A second phase of proposed standards for all-terrain 
vehicles is based on catalyst technology.
    When the proposed emission standards are fully implemented in 2020, 
we expect a 79 percent reduction in HC emissions, 75 percent reduction 
in NOX emissions, and 56 percent reduction in CO emissions 
from these engines, equipment, and vehicles (see Section IX below for 
more details). These emission reductions will reduce ambient 
concentrations of ozone, CO, and PM fine, which is a health concern and 
contributes to visibility impairment. The standards will also reduce 
personal exposure for people who operate or who work with or are 
otherwise in close proximity to these engines and vehicles.
    For the nonroad engines covered by this proposal, the Agency has 
already established in several previous actions that they cause or 
contribute to ozone or carbon monoxide pollution in more than one 
nonattainment area. In three actions in 1996, 1999, and 2000, we made 
separate determinations that each category of nonroad engines covered 
by this proposal specifically contributes to ozone and CO 
nonattainment, and to adverse health effects associated with ambient 
concentrations of PM. These actions are summarized in Table II.A-1. In 
addition, pursuant to Section 213(a)(4) of the Act, we are proposing to 
find that nonroad engines, including construction equipment, farm 
tractors, boats, planes, locomotives, marine engines, and recreational 
vehicles (e.g., off-highway motorcycles, all-terrain-vehicles, and 
snowmobiles), significantly contribute to regional haze, and that these 
engines, particularly snowmobiles, are significant emitters of 
pollutants that are known to impair visibility in federal Class I 
areas. The discussion pertaining to this proposed finding is in Section 
II.D.1, below.

                             Table II.A-1.--Summary of Nonroad Air Quality Findings
----------------------------------------------------------------------------------------------------------------
            Source                 Date of finding       Pollutants covered   Emissions determined to contribute
----------------------------------------------------------------------------------------------------------------
CI Marine.....................  December 29, 1999, 64  Ozone, PM............  HC+NOX, PM, CO.
                                 FR 73300.
Large SI......................  December 7, 2000, 65   Ozone, CO, PM........  HC+NOX, CO, PM.
                                 FR 76790.
Recreational Vehicles.........  December 7, 2000, 65   Ozone, CO, PM........  HC+NOX, CO, PM.
                                 FR 76790.
----------------------------------------------------------------------------------------------------------------

B. What Are the Public Health and Welfare Effects Associated With 
Emissions From Nonroad Engines Subject to the Proposed Standards?

    The engines and vehicles that would be subject to the proposed 
standards generate emissions of HC, CO, PM and air toxics that 
contribute to ozone and CO nonattainment as well as adverse health 
effects associated with ambient concentrations of PM and air toxics. 
Elevated emissions from those recreational vehicles that operate in 
national parks (e.g., snowmobiles) contribute to visibility impairment. 
This section summarizes the general health effects of these substances. 
National inventory estimates are set out in Section II.B, and estimates 
of the expected impact of the proposed control programs are described 
in Section IX. Interested readers are encouraged to refer to the Draft 
Regulatory Support Document for this proposal for more in-depth 
discussions.
1. Health and Welfare Effects Associated With Ground Level Ozone and 
Its Precursors
    Volatile organic compounds (VOC) and NOX are precursors 
in the photochemical reaction which forms tropospheric ozone. Ground-
level ozone, the main ingredient in smog, is formed by complex chemical 
reactions of VOCs and NOX in the presence of heat and 
sunlight. Hydrocarbons (HC) are a large subset of VOC, and to reduce 
mobile-source VOC levels we set maximum emissions limits for 
hydrocarbon and particulate matter emissions.
    A large body of evidence shows that ozone can cause harmful 
respiratory effects including chest pain, coughing, and shortness of 
breath, which affect people with compromised respiratory systems most 
severely. When inhaled, ozone can cause acute respiratory problems; 
aggravate asthma; cause significant temporary decreases in lung 
function of 15 to over 20 percent in some healthy adults; cause 
inflammation of lung tissue; produce changes in lung tissue and 
structure; may increase hospital admissions and emergency room visits; 
and impair the body's immune system defenses, making people more 
susceptible to respiratory illnesses. Children and outdoor workers are 
likely to be exposed to elevated ambient levels of ozone during 
exercise and, therefore, are at a greater risk of experiencing adverse 
health effects. Beyond its human health effects, ozone has been shown 
to injure plants, which has the effect of reducing crop yields and 
reducing productivity in forest ecosystems.
    There is strong and convincing evidence that exposure to ozone is 
associated with exacerbation of asthma-related symptoms. Increases in 
ozone concentrations in the air have been associated with increases in 
hospitalization for respiratory causes for individuals with asthma, 
worsening of symptoms, decrements in lung function, and increased 
medication use, and chronic exposure may cause permanent lung damage. 
The risk of suffering these effects is particularly high for children 
and for people with compromised respiratory systems.
    Ground level ozone today remains a pervasive pollution problem in 
the United States. In 1999, 90.8 million people (1990 census) lived in 
31 areas designated nonattainment under the 1-hour ozone NAAQS.\73\ 
This sharp decline from the 101 nonattainment areas originally 
identified under the Clean Air Act Amendments of 1990 demonstrates the 
effectiveness of the last decade's worth of emission-control programs. 
However, elevated ozone concentrations remain a serious public health 
concern throughout the nation.
---------------------------------------------------------------------------

    \73\ National Air Quality and Emissions Trends Report, 1999, 
EPA, 2001, at Table A-19. This document is available at http://
www.epa.gov/oar/aqtrnd99/. The data from the Trends report are the 
most recent EPA air quality data that have been quality assured. A 
copy of this table can also be found in Docket No. A-2000-01, 
Document No. II-A-64.
---------------------------------------------------------------------------

    Over the last decade, declines in ozone levels were found mostly in 
urban areas, where emissions are heavily influenced by controls on 
mobile sources and their fuels. Twenty-three metropolitan areas have 
realized a decline in ozone levels since 1989, but at the same time 
ozone levels in 11 metropolitan areas with 7 million

[[Page 51105]]

people have increased.\74\ Regionally, California and the Northeast 
have recorded significant reductions in peak ozone levels, while four 
other regions (the Mid-Atlantic, the Southeast, the Central and Pacific 
Northwest) have seen ozone levels increase.
---------------------------------------------------------------------------

    \74\ National Air Quality and Emissions Trends Report, 1998, 
March, 2000, at 28. This document is available at http://
www.epa.gov/oar/aqtrnd98/. Relevant pages of this report can be 
found in Memorandum to Air Docket A-2000-01 from Jean Marie Revelt, 
September 5, 2001, Document No. II-A-63.
---------------------------------------------------------------------------

    The highest ambient concentrations are currently found in suburban 
areas, consistent with downwind transport of emissions from urban 
centers. Concentrations in rural areas have risen to the levels 
previously found only in cities. Particularly relevant to this 
proposal, ozone levels at 17 of our National Parks have increased, and 
in 1998, ozone levels in two parks, Shenandoah National Park and the 
Great Smoky Mountains National Park, were 30 to 40 percent higher than 
the ozone NAAQS over part of the last decade.\75\
---------------------------------------------------------------------------

    \75\ National Air Quality and Emissions Trends Report, 1998, 
March, 2000, at 32. This document is available at http://
www.epa.gov/oar/aqtrnd98/. Relevant pages of this report can be 
found in Memorandum to Air Docket A-2000-01 from Jean Marie Revelt, 
September 5, 2001, Document No. II-A-63.
---------------------------------------------------------------------------

    To estimate future ozone levels, we refer to the modeling performed 
in conjunction with the final rule for our most recent heavy-duty 
highway engine and fuel standards.\76\ We performed ozone air quality 
modeling for the entire Eastern U.S. covering metropolitan areas from 
Texas to the Northeast.\77\ This ozone air quality model was based upon 
the same modeling system as was used in the Tier 2 air quality 
analysis, with the addition of updated inventory estimates for 2007 and 
2030. The results of this modeling were examined for those 37 areas in 
the East for which EPA's modeling predicted exceedances in 2007, 2020, 
and/or 2030 and the current 1-hour design values are above the standard 
or within 10 percent of the standard. This photochemical ozone modeling 
for 2020 predicts exceedances of the 1-hour ozone standard in 32 areas 
with a total of 89 million people (1999 census) after accounting for 
light- and heavy-duty on-highway control programs.\78\ We expect the 
NOX and HC control strategies contained in this proposal for 
nonroad engines will further assist state efforts already underway to 
attain and maintain the 1-hour ozone standard.
---------------------------------------------------------------------------

    \76\ Additional information about this modeling can be found in 
our Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle 
Standards and Highway Diesel Fuel Sulfur Control Requirements, 
document EPA420-R-00-026, December 2000. Docket No. 1-2000-01, 
Document No. II-A-13. This document is also available at 
http://www.epa.gov/otaq/diesel.htm#documents.
    \77\ We also performed ozone air quality modeling for the 
western United States but, as described further in the air quality 
technical support document, model predictions were well below 
corresponding ambient concentrations for out heavy-duty engine 
standards and fuel sulfur control rulemaking. Because of poor model 
performance for this region of the country, the results of the 
Western ozone modeling were not relied on for that rule.
    \78\ Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle 
Standards and Highway Diesel Fuel Sulfur Control Requirements, US 
EPA, EPA420-R-00-026, December 2000, at II-14, Table II.A-2. Docket 
No. A-2000-01, Document Number II-A-13. This document is also 
available at http://www.epa.gov/otaq/diesel.htm#documents.
---------------------------------------------------------------------------

    In addition to the health effects described above, there exists a 
large body of scientific literature that shows that harmful effects can 
occur from sustained levels of ozone exposure much lower than 0.125 
ppm.\79\ Studies of prolonged exposures, those lasting about 7 hours, 
show health effects from prolonged and repeated exposures at moderate 
levels of exertion to ozone concentrations as low as 0.08 ppm. The 
health effects at these levels of exposure include transient pulmonary 
function responses, transient respiratory symptoms, effects on exercise 
performance, increased airway responsiveness, increased susceptibility 
to respiratory infection, increased hospital and emergency room visits, 
and transient pulmonary respiratory inflammation.
---------------------------------------------------------------------------

    \79\ Additional information about these studies can be found in 
Chapter 2 of ``Regulatory Impact Analysis: Heavy-Duty Engine and 
Vehicle Standards and Highway Diesel Fuel Sulfur Control 
Requirements,'' December 2000, EPA420-R-00-026. Docket No. A-2000-
01, Document Number II-A-13. This document is also available at 
http://www.epa.gov/otaq/diesel.htm#documents.
---------------------------------------------------------------------------

    Prolonged and repeated ozone concentrations at these levels are 
common in areas throughout the country, and are found both in areas 
that are exceeding, and areas that are not exceeding, the 1-hour ozone 
standard. Areas with these high concentrations are more widespread than 
those in nonattainment for that 1-hour ozone standard. Monitoring data 
indicate that 333 counties in 33 states exceed these levels in 1997-
99.\80\ The Agency's most recent photochemical ozone modeling forecast 
that 111 million people are predicted to live in areas that are at risk 
of exceeding these moderate ozone levels for prolonged periods of time 
in 2020 after accounting for expected inventory reductions due to 
controls on light- and heavy-duty on-highway vehicles.\81\
---------------------------------------------------------------------------

    \80\ A copy of these data can be found in Air Docket A-2000-01, 
Document No. II-A-80.
    \81\ Memorandum to Docket A-99-06 from Eric Ginsburg, EPA, 
``Summary of Model-Adjusted Ambient Concentrations for Certain 
Levels of Ground-Level Ozone over Prolonged Periods,'' November 22, 
2000, at Table C, Control Scenario--2020 Populations in Eastern 
Metropolitan Counties with Predicted Daily 8-Hour Ozone greater than 
or equal to 0.080 ppm. Docket A-2000-01, Document Number II-B-13.
---------------------------------------------------------------------------

2. Health Effects Associated With Carbon Monoxide
    Carbon monoxide (CO) is a colorless, odorless gas produced through 
the incomplete combustion of carbon-based fuels. Carbon monoxide enters 
the bloodstream through the lungs and reduces the delivery of oxygen to 
the body's organs and tissues. The health threat from CO is most 
serious for those who suffer from cardiovascular disease, particularly 
those with angina or peripheral vascular disease. Healthy individuals 
also are affected, but only at higher CO levels. Exposure to elevated 
CO levels is associated with impairment of visual perception, work 
capacity, manual dexterity, learning ability and performance of complex 
tasks.
    High concentrations of CO generally occur in areas with elevated 
mobile-source emissions. Peak concentrations typically occur during the 
colder months of the year when mobile-source CO emissions are greater 
and nighttime inversion conditions are more frequent. This is due to 
the enhanced stability in the atmospheric boundary layer, which 
inhibits vertical mixing of emissions from the surface.
    The current primary NAAQS for CO are 35 parts per million for the 
one-hour average and 9 parts per million for the eight-hour average. 
These values are not to be exceeded more than once per year. Air 
quality carbon monoxide value is estimated using EPA guidance for 
calculating design values. In 1999, 30.5 million people (1990 census) 
lived in 17 areas designated nonattainment under the CO NAAQS.\82\
---------------------------------------------------------------------------

    \82\ National Air Quality and Emissions Trends Report, 1999, 
EPA, 2001, at Table A-19. This document is available at http://
www.epa.gov/oar/aqtrnd99/. The data from the Trends report are the 
most recent EPA air quality data that have been quality assured. A 
copy of this table can also be found in Docket No. A-2000-01, 
Document No. II-A-64.
---------------------------------------------------------------------------

    Snowmobiles, which have relatively high per engine CO emissions, 
can be a significant source of ambient CO levels in CO nonattainment 
areas. Several states that contain CO nonattainment areas also have 
large populations of registered snowmobiles. This is shown in Table 
II.B-1. A review of snowmobile trail maps indicates that snowmobiles 
are used in these CO nonattainment

[[Page 51106]]

areas or in adjoining counties.\83\ These include the Mt. Spokane and 
Riverside trails near the Spokane, Washington CO nonattainment area; 
the Larimer trails near the Fort Collins, Colorado CO nonattainment 
area; and the Hyatt Lake, Lake of the Woods, and Cold Springs trails 
near the Klamath Falls and Medford, Oregon CO nonattainment area. There 
are also trails in Missoula County, Montana that demonstrate snowmobile 
use in the Missoula, Montana CO nonattainment area. While Colorado has 
a large snowmobile population, the snowmobile trails are fairly distant 
from the Colorado Springs CO nonattainment areas. EPA requests comment 
on the volume and nature of snowmobile use in these and other CO 
nonattainment areas. Of particular interest is information about the 
number of trails in and around CO nonattainment areas, the magnitude of 
snowmobile use on those trails, and the extent to which snowmobiles are 
used off-trail.\84\
---------------------------------------------------------------------------

    \83\ St. Paul, Minnesota was recently reclassified as being in 
attainment but is still considered a maintenance area. There is also 
a significant population of snowmobiles in Minnesota, with 
snowmobile trails in Washington County.
    \84\ The trail maps consulted for this proposal can be found in 
Docket No. A-2000-01, Document No. II-A-65.

                        Table II.B-1.--Snowmobile Use in Selected CO Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
                                                                                                    1998 State
              City and State                          CO nonattainment classification               snowmobile
                                                                                                  population \a\
----------------------------------------------------------------------------------------------------------------
Fairbanks, AK............................  Serious..............................................          12,997
Spokane, WA..............................  Serious..............................................          32,274
Colorado Springs, CO.....................  Moderate.............................................          28,000
Fort Collins, CO.........................  Moderate.............................................
Klamath Falls, OR........................  Moderate.............................................          13,426
Medford, OR..............................  Moderate.............................................
Missoula, MT.............................  Moderate.............................................         14,361
----------------------------------------------------------------------------------------------------------------
\a\ Source: Letter from International Snowmobile Manufacturers Association to US-EPA, July 8, 1999, Docket A-
  2000-01, Document No. II-G.

    Exceedances of the 8-hour CO standard were recorded in three of 
these seven CO nonattainment areas located in the northern portion of 
the country over the five year period from 1994 to 1999: Fairbanks, AK; 
Medford, OR; and Spokane, WA.\85\ Given the variability in CO ambient 
concentrations due to weather patterns such as inversions, the absence 
of recent exceedances for some of these nonattainment areas should not 
be viewed as eliminating the need for further reductions to 
consistently attain and maintain the standard. A review of CO monitor 
data in Fairbanks from 1986 to 1995 shows that while median 
concentrations have declined steadily, unusual combinations of weather 
and emissions have resulted in elevated ambient CO concentrations well 
above the 8-hour standard of 9 ppm. Specifically, a Fairbanks monitor 
recorded average 8-hour ambient concentrations at 16 ppm in 1988, 
around 9 ppm from 1990 to 1992, and then a steady increase in CO 
ambient concentrations at 12, 14 and 16 ppm during some extreme cases 
in 1993, 1994 and 1995, respectively.\86\
---------------------------------------------------------------------------

    \85\ Technical Memorandum to Docket A-2000-01 from Drew Kodjak, 
Attorney-Advisor, Office of Transportation and Air Quality, ``Air 
Quality Information for Selected CO Nonattainment Areas,'' July 27, 
2001, Docket Number A-2000-01, Document Number II-B-18.
    \86\ Air Quality Criteria for Carbon Monoxide, US EPA, EPA 600/
P-99/001F, June 2000, at 3-38, Figure 3-32 (Federal Bldg, AIRS Site 
020900002). Air Docket A-2000-01, Document Number II-A-29. This 
document is also available at http://www.epa.gov/ncea/
coabstract.htm.
---------------------------------------------------------------------------

    Nationally, significant progress has been made over the last decade 
to reduce CO emissions and ambient CO concentrations. Total CO 
emissions from all sources have decreased 16 percent from 1989 to 1998, 
and ambient CO concentrations decreased by 39 percent. During that 
time, while the mobile source CO contribution of the inventory remained 
steady at about 77 percent, the highway portion decreased from 62 
percent of total CO emissions to 56 percent while the nonroad portion 
increased from 17 percent to 22 percent.\87\ Over the next decade, we 
would expect there to be a minor decreasing trend from the highway 
segment due primarily to the more stringent standards for certain 
light-duty trucks (LDT2s).\88\ CO standards for passenger cars and 
other light-duty trucks and heavy-duty vehicles did not change as a 
result of other recent rulemakings). As described in Section II.C, 
below, the engines subject to this rule currently account for about 7 
percent of the mobile source CO inventory; this is expected to increase 
to 10 percent by 2020 without the emission controls proposed in this 
action.
---------------------------------------------------------------------------

    \87\ National Air Quality and Emissions Trends Report, 1998, 
March, 2000; this document is available at http://www.epa.gov/oar/
aqtrnd98/. National Air Pollutant Emission Trends, 1900-1998 (EPA-
454/R-00-002), March, 2000. These documents are available at Docket 
No. A-2000-01, Document No. II-A-72. See also Air Quality Criteria 
for Carbon Monoxide, US EPA, EPA 600/P-99/001F, June 2000, at 3-10. 
Air Docket A-2000-01, Document Number II-A-29. This document is also 
available at http://www.epa.gov/ncea/coabstract.htm.
    \88\ LDT2s are light light-duty trucks greater than 3750 lbs. 
loaded vehicle weight, up through 6000 gross vehicle weight rating.
---------------------------------------------------------------------------

    The state of Alaska recently submitted draft CO attainment SIPs to 
the Agency for the Fairbanks CO nonattainment area. Fairbanks is 
located in a mountain valley with a much higher potential for air 
stagnation than cities within the contiguous United States. Nocturnal 
inversions that give rise to elevated CO concentrations can persist 24-
hours a day due to the low solar elevation, particularly in December 
and January. These inversions typically last from 2 to 4 days (Bradley 
et al., 1992), and thus inversions may continue during hours of maximum 
CO emissions from mobile sources. Despite the fact that snowmobiles are 
largely banned in CO nonattainment areas by the state, the state 
estimated that snowmobiles contributed 0.3 tons/day in 1995 to 
Fairbanks' CO nonattainment area or 1.2 percent of a total inventory of 
23.3 tons per day in 2001.\89\ While Fairbanks has made significant 
progress in reducing ambient CO concentrations, existing climate 
conditions make achieving and maintaining attainment challenging. 
Fairbanks failed to attain the CO NAAQS by the applicable deadline of

[[Page 51107]]

December 21, 2000, and EPA approved a one-year extension in May of 
2001.\90\
---------------------------------------------------------------------------

    \89\ Draft Anchorage Carbon Monoxide Emission Inventory and Year 
2000 Attainment Projections, Air Quality Program, May 2001, Docket 
Number A-2000-01, Document II-A-40; Draft Fairbanks 1995-2001 Carbon 
Monoxide Emissions Inventory, June 1, 2001, Docket Number A-2000-01, 
Document II-A-39.
    \90\ 66 FR 28836, May 25, 2001. Clean Air Act Promulgation of 
Attainment Date Extension for the Fairbanks North Star Borough 
Carbon Monoxide Nonattainment Area, AK, Direct Final Rule.
---------------------------------------------------------------------------

    In addition to the health effects that can result from exposure to 
carbon monoxide, this pollutant also can contribute to ground level 
ozone formation.\91\ Recent studies in atmospheric chemistry in urban 
environments suggest CO can react with hydrogen-containing radicals, 
leaving fewer of these to combine with non-methane hydrocarbons and 
thus leading to increased levels of ozone. Few analyses have been 
performed that estimate these effects, but a study of an ozone episode 
in Atlanta, GA in 1988 found that CO accounted for about 17.5 percent 
of the ozone formed (compared to 82.5 percent for volatile organic 
compounds). While different cities may have different results, the 
effects of CO emissions on ground level ozone are not insignificant. 
The engines that are the subject of the proposed standards are 
contributors to these effects in urban areas, particularly because 
their per engine emissions are so high. For example, CO emissions from 
an off-highway motorcycle are high relative to a passenger car, (32 g/
mi compared to 4.2 g/mi). The CO controls contained in this proposal 
will further assist state efforts already underway to attain and 
maintain the CO NAAQS.
---------------------------------------------------------------------------

    \91\ U.S. EPA, Air Quality Criteria for Carbon Monoxide, EPA 
600/P-99.001F, June 2000, Section 3.2.3. Air Docket A-2000-01, 
Document Number II-A-29. This document is also available at http://
www.epa.gov/ncea/coabstract.htm.
---------------------------------------------------------------------------

3. Health and Welfare Effects Associated With Particulate Matter
    Nonroad engines and vehicles that would be subject to the proposed 
standards contribute to ambient particulate matter (PM) levels in two 
ways. First, they contribute through direct emissions of particulate 
matter. Second, they contribute to indirect formation of PM through 
their emissions of organic carbon, especially HC. Organic carbon 
accounts for between 27 and 36 percent of fine particle mass depending 
on the area of the country.
    Particulate matter represents a broad class of chemically and 
physically diverse substances. It can be principally characterized as 
discrete particles that exist in the condensed (liquid or solid) phase 
spanning several orders of magnitude in size. All particles equal to 
and less than 10 microns are called PM10. Fine particles can 
be generally defined as those particles with an aerodynamic diameter of 
2.5 microns or less (also known as PM2.5), and coarse 
fraction particles are those particles with an aerodynamic diameter 
greater than 2.5 microns, but equal to or less than a nominal 10 
microns.
    Particulate matter, like ozone, has been linked to a range of 
serious respiratory health problems. Scientific studies suggest a 
likely causal role of ambient particulate matter (which is attributable 
to several sources including mobile sources) in contributing to a 
series of health effects.\92\ The key health effects categories 
associated with ambient particulate matter include premature mortality, 
aggravation of respiratory and cardiovascular disease (as indicated by 
increased hospital admissions and emergency room visits, school 
absences, work loss days, and restricted activity days), aggravated 
asthma, acute respiratory symptoms, including aggravated coughing and 
difficult or painful breathing, chronic bronchitis, and decreased lung 
function that can be experienced as shortness of breath. Observable 
human noncancer health effects associated with exposure to diesel PM 
include some of the same health effects reported for ambient PM such as 
respiratory symptoms (cough, labored breathing, chest tightness, 
wheezing), and chronic respiratory disease (cough, phlegm, chronic 
bronchitis and suggestive evidence for decreases in pulmonary 
function). Symptoms of immunological effects such as wheezing and 
increased allergenicity are also seen. Exposure to fine particles is 
closely associated with such health effects as premature mortality or 
hospital admissions for cardiopulmonary disease.
---------------------------------------------------------------------------

    \92\ EPA (1996) Review of the National Ambient Air Quality 
Standards for Particulate Matter: Policy Assessment of Scientific 
and Technical Information OAQPS Staff Paper. EPA-452/R-96-013. 
Docket Number A-99-06, Documents Nos. II-A-18, 19, 20, and 23. The 
particulate matter air quality criteria documents are also available 
at http://www.epa.gov/ncea/partmatt.htm.
---------------------------------------------------------------------------

    PM also causes adverse impacts to the environment. Fine PM is the 
major cause of reduced visibility in parts of the United States, 
including many of our national parks. Other environmental impacts occur 
when particles deposit onto soils, plants, water or materials. For 
example, particles containing nitrogen and sulphur that deposit on to 
land or water bodies may change the nutrient balance and acidity of 
those environments. Finally, PM causes soiling and erosion damage to 
materials, including culturally important objects such as carved 
monuments and statues. It promotes and accelerates the corrosion of 
metals, degrades paints, and deteriorates building materials such as 
concrete and limestone.
    The NAAQS for PM10 were established in 1987. According 
to these standards, the short term (24-hour) standard of 150 
g/m3 is not to be exceeded more than once per year 
on average over three years. The long-term standard specifies an 
expected annual arithmetic mean not to exceed 50 g/
m3 over three years. The most recent PM10 
monitoring data indicate that 14 designated PM10 
nonattainment areas with a projected population of 23 million violated 
the PM10 NAAQS in the period 1997-99. In addition, there are 
25 unclassifiable areas that have recently recorded ambient 
concentrations of PM10 above the PM10 NAAQS.\93\
---------------------------------------------------------------------------

    \93\ EPA adopted a policy in 1996 that allows areas with 
PM10 exceedances that are attributable to natural events 
to retain their designation as unclassifiable if the State is taking 
all reasonable measures to safeguard public health regardless of the 
sources of PM10 emissions.
---------------------------------------------------------------------------

    Current 1999 PM2.5 monitored values, which cover about a 
third of the nation's counties, indicate that at least 40 million 
people live in areas where long-term ambient fine particulate matter 
levels are at or above 16 g/m3 (37 percent of the 
population in the areas with monitors).\94\ This 16 g/
m3 threshold is the low end of the range of long term 
average PM2.5 concentrations in cities where statistically 
significant associations were found with serious health effects, 
including premature mortality.\95\ To estimate the number of people who 
live in areas where long-term ambient fine particulate matter levels 
are at or above 16 g/m3 but for which there are no 
monitors, we can use modeling. According to our national modeled 
predictions, there were a total of 76 million people (1996 population) 
living in areas with modeled annual average PM2.5 
concentrations at or above 16 g/m3 (29 percent of 
the population).\96\
---------------------------------------------------------------------------

    \94\ Memorandum to Docket A-99-06 from Eric O. Ginsburg, Senior 
Program Advisor, ``Summary of 1999 Ambient Concentrations of Fine 
Particulate Matter,'' November 15, 2000. Air Docket A-2000-01, 
Document No. II-B-12.
    \95\ EPA (1996) Review of the National Ambient Air Quality 
Standards for Particulate Matter: Policy Assessment of Scientific 
and Technical Information OAQPS Staff Paper. EPA-452/R-96-013. 
Docket Number A-99-06, Documents Nos. II-A-18, 19, 20, and 23. The 
particulate matter air quality criteria documents are also available 
at http://www.epa.gov/ncea/partmatt.htm.
    \96\ Memorandum to Docket A-99-06 from Eric O. Ginsburg, Senior 
Program Advisor, ``Summary of Absolute Modeled and Model-Adjusted 
Estimates of Fine Particulate Matter for Selected Years,'' December 
6, 2000. Air Docket A-2000-01, Document No. II-B-14.
---------------------------------------------------------------------------

    To estimate future PM2.5 levels, we refer to the 
modeling performed in

[[Page 51108]]

conjunction with the final rule for our most recent heavy-duty highway 
engine and fuel standards, using EPA's Regulatory Model System for 
Aerosols and Deposition (REMSAD).\97\ The most appropriate method of 
making these projections relies on the model to predict changes between 
current and future states. Thus, we have estimated future conditions 
only for the areas with current PM2.5 monitored data (which 
cover about a third of the nation's counties). For these counties, 
REMSAD predicts the current level of 37 percent of the population 
living in areas where fine PM levels are at or above 16 g/
m3 to increase to 49 percent in 2030.\98\
---------------------------------------------------------------------------

    \97\ Additional information about the Regulatory Model System 
for Aerosols and Deposition (REMSAD) and our modeling protocols can 
be found in our Regulatory Impact Analysis: Heavy-Duty Engine and 
Vehicle Standards and Highway Diesel Fuel Sulfur Control 
Requirements, document EPA420-R-00-026, December 2000. Docket No. A-
2000-01, Document No. A-II-13. This document is also available at 
http://www.epa.gov/otaq/disel.htm#documents.
    \98\ Technical Memorandum, EPA Air Docket A-99-06, Eric O. 
Ginsburg, Senior Program Advisor, Emissions Monitoring and Analysis 
Division, OAQPS, Summary of Absolute Modeled and Model-Adjusted 
Estimates of Fine Particulate Matter for Selected Years, December 6, 
2000, Table P-2. Docket Number 2000-01, Document Number II-B-14.
---------------------------------------------------------------------------

    Emissions of HCs from snowmobiles contribute to secondary formation 
of fine particulate matter which can cause a variety of adverse health 
and welfare effects, including visibility impairment discussed in 
Section II.D.1(b) below. For 20 counties across nine states, snowmobile 
trails are found within or near counties that registered ambient PM 2.5 
concentrations at or above 15 g/m3, the level of 
the revised national ambient air quality standard for fine 
particles.\99\ Fine particles may remain suspended for days or weeks 
and travel hundreds to thousands of kilometers, and thus fine particles 
emitted or created in one county may contribute to ambient 
concentrations in a neighboring county.\100\ These counties are listed 
in Table II.B-2. To obtain the information about snowmobile trails 
contained in Table II.B-2, we consulted snowmobile trail maps that were 
supplied by various states.\101\
---------------------------------------------------------------------------

    \99\ Memo to file from Terence Fitz-Simons, OAQPS, Scott 
Mathias, OAQPS, Mike Rizzo, Region 5, ``Analyses of 1999 PM Data for 
the PM NAAQS Review,'' November 17, 2000, with attachment B, 1999 
PM2.5 Annual Mean and 98th Percentile 24-Hour Average 
Concentrations. Docket No. A-2000-01, Document No. II-B-17.
    \100\ Review of the National Ambient Air Quality Standards for 
Particulate Matter: Policy Assessment for Scientific and Technical 
Information, OAQPS Staff Paper, EPA-452/R-96-013, July, 1996, at IV-
7.
    \101\ The trail maps consulted for this proposal can be found in 
Docket No. A-2000-01, Document No. II-A-65.

         Table II.B-2.--Counties With Annual PM2.5 Levels Above 16 g/m\3\ and Snowmobile Trails
----------------------------------------------------------------------------------------------------------------
   State and PM2.5 exceedance county    County with snowmobile trails     Proximity to PM2.5 exceedance county
----------------------------------------------------------------------------------------------------------------
Ohio:
  Mahoning............................  Mahoning.....................
  Trumbull............................  Trumbull.....................
  Summit..............................  Summit.......................
  Montgomery..........................  Montgomery...................
  Portage.............................  Portage......................
  Franklin............................  Delaware.....................  Borders North.
  Marshall/Ohio (WV)..................  Belmont......................  Borders West.
Montana...............................  Lincoln......................  Lincoln
California:
  Tulane..............................  Tulane.......................
  Butte...............................  Butte........................
  Fresno..............................  Fresno.......................
  Kern................................  Kern.........................
Minnesota:
  Washington..........................  Washington...................
  Wright..............................  Wright.......................
Wisconsin:
  Waukesha............................  Waukesha.....................
  Milwaukee...........................  Milwaukee....................
Oregon:
  Jackson.............................  Douglas......................  Borders NNE.
  Klamath.............................  Douglas......................  Borders North.
Pennsylvania: Washington..............  Layette......................  Borders East.
                                        Somerset.....................
Illinois: Rock Island.................  Rock Island
                                        Henry........................  Borders East.
Iowa: Rock Island (IL)................  Dubuque......................  Borders West.
----------------------------------------------------------------------------------------------------------------

    We expect the PM control strategies contained in this proposal 
would further assist state efforts already underway to attain and 
maintain the PM NAAQS.
4. Health Effects Associated With Air Toxics
    In addition to the human health and welfare impacts described 
above, emissions from the engines covered by this proposal also contain 
several other substances that are known or suspected human or animal 
carcinogens, or have serious noncancer health effects. These include 
benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and acrolein. The 
health effects of these air toxics are described in more detail in 
Chapter 1 of the Draft Regulatory Support Document for this rule. 
Additional information can also be found in the Technical Support

[[Page 51109]]

Document for our final Mobile Source Air Toxics rule.102
---------------------------------------------------------------------------

    \102\ See our Mobile Source Air Toxics final rulemaking, 66 FR 
17230, March 29, 2001, and the Technical Support Document for that 
rulemaking. Docket No. A-2000-01, Documents Nos. II-A-42 and II-A-
30.
---------------------------------------------------------------------------

    The hydrocarbon controls contained in this proposal are expected to 
reduce exposure to air toxics and therefore may help reduce the impact 
of these engines on cancer and noncancer health effects.

C. What Is the Inventory Contribution From the Nonroad Engines and 
Vehicles That Would Be Subject to This Proposal?

    The contribution of emissions from the nonroad engines and vehicles 
that would be subject to the proposed standards to the national 
inventories of pollutants that are associated with the health and 
public welfare effects described in Section II.B are considerable. To 
estimate nonroad engine and vehicle emission contributions, we used the 
latest version of our NONROAD emissions model. This model computes 
nationwide, state, and county emission levels for a wide variety of 
nonroad engines, and uses information on emission rates, operating 
data, and population to determine annual emission levels of various 
pollutants. A more detailed description of the model and our estimation 
methodology can be found in the Chapter 6 of the Draft Regulatory 
Support Document.
    Baseline emission inventory estimates for the year 2000 for the 
categories of engines and vehicles covered by this proposal are 
summarized in Table II.C-1. This table shows the relative contributions 
of the different mobile-source categories to the overall national 
mobile-source inventory. Of the total emissions from mobile sources, 
the categories of engines and vehicles covered by this proposal 
contribute about 13 percent, 3 percent, 6 percent, and 1 percent of HC, 
NOX, CO, and PM emissions, respectively, in the year 2000. 
The results for industrial SI engines indicate they contribute 
approximately 3 percent to HC, NOX, and CO emissions from 
mobile sources. The results for land-based recreational engines reflect 
the impact of the significantly different emissions characteristics of 
two-stroke engines. These engines are estimated to contribute 10 
percent of HC emissions and 3 percent of CO from mobile sources. 
Recreational CI marine contribute less than 1 percent to NOX 
mobile source inventories. When only nonroad emissions are considered, 
the engines and vehicles that would be subject to the proposed 
standards would account for a larger share.
    Our draft emission projections for 2020 for the nonroad engines and 
vehicles subject to this proposal show that emissions from these 
categories are expected to increase over time if left uncontrolled. The 
projections for 2020 are summarized in Table II.C-2 and indicate that 
the categories of engines and vehicles covered by this proposal are 
expected to contribute 33 percent, 9 percent, 9 percent, and 2 percent 
of HC, NOX, CO, and PM emissions in the year 2020. 
Population growth and the effects of other regulatory control programs 
are factored into these projections. The relative importance of 
uncontrolled nonroad engines is higher than the projections for 2000 
because there are already emission control programs in place for the 
other categories of mobile sources which are expected to reduce their 
emission levels. The effectiveness of all control programs is offset by 
the anticipated growth in engine populations.

                                   Table II.C-1.--Modeled Annual Emission Levels for Mobile-Source Categories in 2000
                                                                  [Thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           NOX                   HC                    CO                    PM
                                                                 ---------------------------------------------------------------------------------------
                            Category                                          Percent               Percent               Percent               Percent
                                                                     Tons    of mobile     Tons    of mobile     Tons    of mobile     Tons    of mobile
                                                                               source                source                source                source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to proposed standards.................        343        2.6        985       12.9      4,870        6.3        8.3        1.2
                                                                 =======================================================================================
Highway Motorcycles.............................................          8        0.1         84        1.1        329        0.4        0.4        0.1
Nonroad Industrial SI > 19 kW...................................        306        2.3        247        3.2      2,294        3.0        1.6        0.2
Recreational SI.................................................         13        0.1        737        9.7      2,572        3.3        5.7        0.8
Recreation Marine CI............................................         24        0.2          1        0.0          4        0.0          1        0.1
Marine SI Evap..................................................          0        0.0         89        1.2          0        0.0          0        0.0
Marine SI Exhaust...............................................         32        0.2        708        9.3      2,144        2.8         38        5.4
Nonroad SI  19 kW...............................................        106        0.8      1,460       19.1     18,359       23.6         50        7.2
Nonroad CI......................................................      2,625       19.5        316        4.1      1,217        1.6        253       36.2
Commercial Marine CI............................................        977        7.3         30        0.4        129        0.2         41        5.9
Locomotive......................................................      1,192        8.9         47        0.6        119        0.2         30        4.3
                                                                 ---------------------------------------------------------------------------------------
Total Nonroad...................................................      5,275         39      3,635         48     26,838         35        420         60
Total Highway...................................................      7,981         59      3,811         50     49,811         64        240         34
Aircraft........................................................        178          1        183          2      1,017          1         39          6
                                                                 ---------------------------------------------------------------------------------------
Total Mobile Sources............................................     13,434        100      7,629        100     77,666        100        699        100
                                                                 =======================================================================================
Total Man-Made Sources..........................................     24,538  .........     18,575  .........     99,745  .........      3,095  .........
                                                                 =======================================================================================
Mobile Source percent of Total Man-Made Sources.................         55  .........         41  .........         78  .........         23  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 51110]]

                                   Table II.C-2.--Modeled Annual Emission Levels for Mobile-Source Categories in 2020
                                                                  [Thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           NOX                   HC                    CO                    PM
                                                                 ---------------------------------------------------------------------------------------
                            Category                                          Percent               Percent               Percent               Percent
                                                                     Tons    of mobile     Tons    of mobile     Tons    of mobile     Tons    of mobile
                                                                               source                source                source                source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to proposed standards.................        552        8.9      2,055       33.4      8,404        9.4       11.4        1.8
                                                                 =======================================================================================
Highway Motorcyles..............................................         14        0.2        144        2.3        569        0.6        0.8        0.1
Nonroad Industrial SI > 19 kW...................................        486        7.8        348        5.7      2,991        3.3        2.4        0.4
Recreational SI.................................................         27        0.4      1,706       27.7      5,407        3.3        7.5        1.2
Recreation Marine CI............................................         39        0.6          1        0.0          6        0.0        1.5        0.2
Marine SI Evap..................................................          0        0.0        102        1.4          0        0.0          0        0.0
Marine SI Exhaust...............................................         58        0.9        284        4.6      1,985        2.2         28        4.4
Nonroad SI  19 kW...............................................        106        1.7        986       16.0     27,352       30.5         77       12.2
Nonroad CI......................................................      1,791       28.8        142        2.3      1,462        1.6        261       41.3
Commercial Marine CI............................................        819       13.2         35        0.6        160        0.2         46        7.3
Locomotive......................................................        611        9.8         35        0.6        119        0.1         21        3.3
                                                                 ---------------------------------------------------------------------------------------
Total Nonroad...................................................      3,937         63      3,639         59     39,482         44        444         70
Total Highway...................................................      2,050         33      2,278         37     48,903         54        145         23
Aircraft........................................................        232          4        238          4      1,387          2         43          7
                                                                 ---------------------------------------------------------------------------------------
Total Mobile Sources............................................      6,219        100      6,155        100     89,772        100        632        100
                                                                 =======================================================================================
Total Man-Made Sources..........................................     16,195  .........     16,215  .........    113,440  .........      3,016  .........
                                                                 =======================================================================================
Mobile Source percent of Total Man-Made Sources.................         38  .........         38  .........         79  .........         21  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

D. Regional and Local-Scale Public Health and Welfare Effects

    The previous section describes national-scale adverse public health 
effects associated with the nonroad engines and vehicles covered by 
this proposal. This section describes significant adverse health and 
welfare effects arising from the usage patterns of snowmobiles, Large 
SI engines, and gasoline marine engines on the regional and local 
scale. Studies suggest that emissions from these engines can be 
concentrated in specific areas, leading to elevated ambient 
concentrations of particular pollutants and associated elevated 
personal exposures to operators and by-standers. Recreational vehicles, 
and particularly snowmobiles, are typically operating in rural areas 
such as national parks and wilderness areas, and emissions from these 
vehicles contribute to ambient particulate matter which is a leading 
component of visibility impairment.
1. Health and Welfare Effects Related to Snowmobiles
    In this section, we describe more localized human health and 
welfare effects associated with snowmobile emissions: visibility 
impairment and personal exposure to air toxics and CO. We describe the 
contribution of snowmobile HC emissions to secondary formation of fine 
particles, which are the leading component of visibility impairment and 
adverse health effects related to ambient PM2.5 concentrations greater 
than 16 ug/m3. We also discuss personal exposure to CO emissions and 
air toxics. Gaseous air toxics are components of hydrocarbons, and CO 
personal exposure measurements suggest that snowmobile riders and 
bystanders are exposed to unhealthy levels of gaseous air toxics (e.g., 
benzene) and CO.
    a. Nonroad Engines and Regional Haze. The Clean Air Act established 
special goals for improving visibility in many national parks, 
wilderness areas, and international parks. In the 1977 amendments to 
the Clean Air Act, Congress set as a national goal for visibility the 
``prevention of any future, and the remedying of any existing, 
impairment of visibility in mandatory class I Federal areas which 
impairment results from manmade air pollution'' (CAA section 
169A(a)(1)). The Amendments called for EPA to issue regulations 
requiring States to develop implementation plans that assure 
``reasonable progress'' toward meeting the national goal (CAA Section 
169A(a)(4)). EPA issued regulations in 1980 to address visibility 
problems that are ``reasonably attributable'' to a single source or 
small group of sources, but deferred action on regulations related to 
regional haze, a type of visibility impairment that is caused by the 
emission of air pollutants by numerous emission sources located across 
a broad geographic region. At that time, EPA acknowledged that the 
regulations were only the first phase for addressing visibility 
impairment. Regulations dealing with regional haze were deferred until 
improved techniques were developed for monitoring, for air quality 
modeling, and for understanding the specific pollutants contributing to 
regional haze.
    In the 1990 Clean Air Act amendments, Congress provided additional 
emphasis on regional haze issues (see CAA section 169B). In 1999 EPA 
finalized a rule that calls for States to establish goals and emission 
reduction strategies for improving visibility in all 156 mandatory 
Class I national parks and wilderness areas. In that rule, EPA also 
encouraged the States to work together in developing and implementing 
their air quality plans. The regional haze program is designed to 
improve visibility and air quality in our most treasured natural areas. 
At the same time, control strategies designed to improve visibility in 
the national parks and wilderness areas will improve visibility over 
broad geographic areas.
    Regional haze is caused by the emission from numerous sources 
located over a wide geographic area. Such sources include, but are not 
limited to, major and minor stationary sources, mobile sources, and 
area sources. Visibility impairment is caused by pollutants (mostly 
fine particles and precursor gases) directly emitted to the

[[Page 51111]]

atmosphere by several activities (such as electric power generation, 
various industry and manufacturing processes, truck and auto emissions, 
construction activities, etc.). These gases and particles scatter and 
absorb light, removing it from the sight path and creating a hazy 
condition.
    Some fine particles are formed when gases emitted to the air form 
particles as they are carried downwind (examples include sulfates, 
formed from sulfur dioxide, and nitrates, formed from nitrogen oxides). 
These activities generally span broad geographic areas and fine 
particles can be transported great distances, sometimes hundreds or 
thousands of miles. Consequently, visibility impairment is a national 
problem. Without the effects of pollution a natural visual range is 
approximately 140 miles in the West and 90 miles in the East. However, 
fine particles have significantly reduced the range that people can see 
and in the West the current range is 33-90 miles and in the East it is 
only 14 to 24 miles.
    Because of evidence that fine particles are frequently transported 
hundreds of miles, all 50 states, including those that do not have 
Class I areas, will have to participate in planning, analysis and, in 
many cases, emission control programs under the regional haze 
regulations. Even though a given State may not have any Class I areas, 
pollution that occurs in that State may contribute to impairment in 
Class I areas elsewhere. The rule encourages states to work together to 
determine whether or how much emissions from sources in a given state 
affect visibility in a downwind Class I area.
    The regional haze program calls for states to establish goals for 
improving visibility in national parks and wilderness areas to improve 
visibility on the haziest 20 percent of days and to ensure that no 
degradation occurs on the clearest 20 percent of days. The rule 
requires states to develop long-term strategies including enforceable 
measures designed to meet reasonable progress goals. Under the regional 
haze program, States can take credit for improvements in air quality 
achieved as a result of other Clean Air Act programs, including 
national mobile-source programs.
    Nonroad engines (including construction equipment, farm tractors, 
boats, planes, locomotives, recreational vehicles, and marine engines) 
contribute significantly to regional haze. This is because there are 
nonroad engines in all of the states, and their emissions contain 
precursors of fine PM and organic carbon that are transported and 
contribute to the formation of regional haze throughout the country and 
in Class I areas specifically. As illustrated in Table II.D-1, nonroad 
engines are expected to contribute 15 percent of national VOC 
emissions, 23 percent of national NOX emissions, 6 percent 
of national SOx emissions, and 14 percent of national PM10 emissions. 
Snowmobiles alone are estimated to emit 208,926 tons of total 
hydrocarbons (THC), 1,461 tons of NOX, 2,145 tons of SOx, 
and 5,082 tons of PM in 2007.

                                              Table II.D-1.--National Emissions of Various Pollutants--2007
                                                                 [Thousands short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    VOC                     NOX                     SOX                    PM10
                         Source                          -----------------------------------------------------------------------------------------------
                                                             Tons       Percent      Tons       Percent      Tons       Percent      Tons       Percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Heavy-Duty Highway......................................         413           3       2,969          14          24           0         115           4
Light-Duty Highway......................................       2,596          18       2,948          14          24           0          82           3
Nonroad.................................................       2,115          15       4,710          23       1,027           6         407          14
Electric General........................................          35           0       4,254          21      10,780          63         328          12
Point...................................................       1,639          11       3,147          15       3,796          22       1,007          36
Area....................................................       7,466          52       2,487          12       1,368           8         874          31
                                                         ------------            ------------            ------------            ------------
      Total.............................................      14,265                  20,516                  17,019                   2,814
--------------------------------------------------------------------------------------------------------------------------------------------------------

    b. Snowmobiles and Visibility Impairment. As noted above, EPA 
issued regulations in 1980 to address Class I area visibility 
impairment that is ``reasonably attributable'' to a single source or 
small group of sources. In 40 CFR Part 51.301 of the visibility 
regulations, visibility impairment is defined as ``any humanly 
perceptible change in visibility (light extinction, visual range, 
contrast, coloration) from that which would have existed under natural 
conditions.'' States are required to develop implementation plans that 
include long-term strategies for improving visibility in each class I 
area. The long-term strategies under the 1980 regulations should 
consist of measures to reduce impacts from local sources and groups of 
sources that contribute to poor air quality days in the class I area. 
Types of impairment covered by these regulations includes layered hazes 
and visible plumes. While these kinds of visibility impairment can be 
caused by the same pollutants and processes as those that cause 
regional haze, they generally are attributed to a smaller number of 
sources located across a smaller area. The Clean Air Act and associated 
regulations call for protection of visibility impairment in class I 
areas from localized impacts as well as broader impacts associated with 
regional haze.
    Visibility and particle monitoring data are available for 8 Class I 
areas where snowmobiles are commonly used. These are: Acadia, Boundary 
Waters, Denali, Mount Rainier, Rocky Mountain, Sequoia and Kings 
Canyon, Voyageurs, and Yellowstone.\103\ Visibility and fine particle 
data for these parks are set out in Table II.D-2. This table shows the 
number of monitored days in the winter that fell within the 20-percent 
haziest days for each of these eight parks. Monitors collect data two 
days a week for a total of about 104 days of monitored values. Thus, 
for a particular site, a maximum of 21 worst possible days of these 104 
days with monitored values constitute the set of 20-percent haziest 
days during a year which are tracked as the primary focus of regulatory 
efforts.\104\ With the exception of Denali in Alaska, we defined the 
snowmobile season as January 1 through March 15 and December 15 through 
December 31 of the same calendar year, consistent with the methodology 
used in the Regional Haze Rule, which is calendar-year based. For 
Denali in

[[Page 51112]]

Alaska, the snowmobile season is October 1 to April 30. The Agency 
would be interested in comments from the public on the start and end 
dates for the typical snowmobile season at each of these national 
parks.
---------------------------------------------------------------------------

    \103\ No data were available at five additional parks where 
snowmobiles are also commonly used: Black Canyon of the Gunnison, 
CO, Grant Teton, WY, Northern Cascades, WA, Theodore Roosevelt, ND, 
and Zion, UT.
    \104\ Letter from Debra C. Miller, Data Analyst, National Park 
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01, 
Document Number. II-B-28.

  Table II.D-2.--Winter Days That Fall Within the 20 Percent Haziest Days at National Parks Used by Snowmobiles
----------------------------------------------------------------------------------------------------------------
                                                                             Number of sampled wintertime days
                                                                              within 20 percent haziest days
             NPS Unit                             State(s)                     (maximum of 21 sampled days)
                                                                         ---------------------------------------
                                                                            1996      1997      1998      1999
----------------------------------------------------------------------------------------------------------------
Acadia NP........................  ME...................................        4         4         2         1
Denali NP and Preserve...........  AK...................................       10        10        12         9
Mount Rainier NP.................  WA...................................        1         3         1         1
Rocky Mountain NP................  CO...................................        2         1         2         1
Sequoia and Kings Canyon NP......  CA...................................        4         9         1         8
Voyageurs NP (1989-1992).........  MN...................................     1989      1990      1991      1992
                                                                                3         4         6         8
--Boundary Waters USFS Wilderness  MN...................................        2         5         1         5
 Area (close to Voyaguers with
 recent data).
Yellowstone NP...................  ID, MT, WY...........................        0         2         0        0
----------------------------------------------------------------------------------------------------------------
Source: Letter from Debra C. Miller, Data Analyst, National Park Service, to Drew Kodjak, August 22, 2001.
  Docket No. A-2000-01, Document Number. II-B-28.

    The information presented in Table II.D-2 shows that visibility 
data support a conclusion that there are at least eight Class I Areas 
(7 in National Parks and one in a Wilderness Area) frequented by 
snowmobiles with one or more wintertime days within the 20-percent 
haziest days of the year. For example, Rocky Mountain National Park in 
Colorado was frequented by about 27,000 snowmobiles during the 1998-
1999 winter. Of the monitored days characterized as within the 20-
percent haziest monitored days, two (2) of those days occurred during 
the wintertime when snowmobile emissions such as hydrocarbons 
contributed to visibility impairment. According to the National Park 
Service, ``[s]ignificant differences in haziness occur at all eight 
sites between the averages of the clearest and haziest days. 
Differences in mean standard visual range on the clearest and haziest 
days fall in the approximate range of 115-170 km.'' \105\
---------------------------------------------------------------------------

    \105\ Letter from Debra C. Miller, Data Analyst, National Park 
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01, 
Document Number. II-B-28.
---------------------------------------------------------------------------

    Ambient concentrations of fine particles are the primary pollutant 
responsible for visibility impairment. Five pollutants are largely 
responsible for the chemical composition of fine particles: sulfates, 
nitrates, organic carbon particles, elemental carbon, and crustal 
material. Hydrocarbon emissions from automobiles, trucks, snowmobiles, 
and other industrial processes are common sources of organic carbon. 
The organic carbon fraction of fine particles ranges from 47 percent in 
Western areas such as Denali National Park, to 28 percent in Rocky 
Mountain National Park, to 13 percent in Acadia National Park.\106\
---------------------------------------------------------------------------

    \106\ Letter from Debra C. Miller, Data Analyst, National Park 
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01, 
Document Number. II-B-28.
---------------------------------------------------------------------------

    The contribution of snowmobiles to elemental carbon and nitrates is 
small. Their contribution to sulfates is a function of fuel sulfur and 
is small and will decrease even more as the sulfur content of their 
fuel decreases due to our recently finalized fuel sulfur requirements. 
In the winter months, however, hydrocarbon emissions from snowmobiles 
can be significant, as indicated in Table II.D-3, and these HC 
emissions can contribute significantly to the organic carbon fraction 
of fine particles which are largely responsible for visibility 
impairment. This is because they are typically powered by two-stroke 
engines that emit large amounts of hydrocarbons. In Yellowstone, a park 
with high snowmobile usage during the winter months, snowmobile 
hydrocarbon emissions can exceed 500 tons per year, as much as several 
large stationary sources. Other parks with less snowmobile traffic are 
less impacted by these hydrocarbon emissions.\107\
---------------------------------------------------------------------------

    \107\ Technical Memorandum, Aaron Worstell, Environmental 
Engineer, National Park Service, Air Resources Division, Denver, 
Colorado, particularly Table 1. Docket No. A-2000-01, Document 
Number II-G-178.
---------------------------------------------------------------------------

    Table II.D-3 shows modeled tons of four pollutants during the 
winter season in five Class I national parks for which we have 
estimates of snowmobile use. The national park areas outside of Denali 
in Alaska are open to snowmobile operation in accordance with special 
regulations (36 CFR Part 7). Denali National Park permits snowmobile 
operation by local rural residents engaged in subsistence uses (36 CFR 
Part 13). Emission calculations are based on an assumed 2 hours of use 
per snowmobile visit at 16 hp with the exception of Yellowstone where 4 
hours of use at 16 hp was assumed. The emission factors used to 
estimate these emissions are identical to those used by the NONROAD 
model. Two-stroke snowmobile emission factors are: 111 g/hp-hr HC, 296 
g/hp-hr CO, 0.86 g/hp-hr NOX, and 2.7 g/hp-hr PM. These 
emission factors are based on several engine tests performed by the 
International Snowmobile Manufacturers Association (ISMA) and the 
Southwest Research Institute (SwRI). These emission factors are still 
under review, and the emissions estimates may change pending the 
outcome of that review.

[[Page 51113]]

                                Table II.D-3.--Winter Season Snowmobile Emissions
                                           [Tons; 1999 Winter Season]
----------------------------------------------------------------------------------------------------------------
                            NPS unit                                  HC          CO          NOX         PM
----------------------------------------------------------------------------------------------------------------
Denali NP & Preserve............................................        >9.8       >26.1       >0.08       >0.24
Grand Teton NP..................................................        13.7        36.6         0.1         0.3
Rocky Mountain NP...............................................       106.7       284.7         0.8         2.6
Voyageurs NP....................................................       138.5       369.4         1.1         3.4
Yellowstone NP..................................................       492.0     1,311.9         3.8       12.0
----------------------------------------------------------------------------------------------------------------
Source: Letter from Aaron J. Worstell, Environmental Engineer, National Park Service, Air Resources Division, to
  Drew Kodjak, August 21, 2001, particularly Table 1. Docket No. A-2000-01, Document No. II-G-178.

    Inventory analysis performed by the National Park Service for 
Yellowstone National Park suggests that snowmobile emissions can be a 
significant source of total annual mobile source emissions for the park 
year round. Table II.D-4 shows that in the 1998 winter season 
snowmobiles contributed 64 percent, 39 percent, and 30 percent of HC, 
CO, and PM emissions.\108\ It should be noted that the snowmobile 
emission factors used to estimate these contributions are currently 
under review, and the snowmobile emissions may be revised down. 
However, when the emission factors used by EPA in its NONROAD model are 
used, the contribution of snowmobiles to total emissions in Yellowstone 
remains significant: 59 percent, 33 percent, and 45 percent of HC, CO 
and PM emissions. The University of Denver used remote-sensing 
equipment to estimate snowmobile HC emissions at Yellowstone during the 
winter of 1998-1999, and estimated that snowmobiles contribute 77% of 
annual hydrocarbon emissions at the park.\109\ The portion of 
wintertime emissions attributable to snowmobiles is even higher, since 
all snowmobile emissions occur during the winter months.
---------------------------------------------------------------------------

    \108\ National Park Service, February 2000. Air Quality Concerns 
Related to Snowmobile Usage in National Parks. Air Docket A-2000-01, 
Document No. II-A-44.
    \109\ G. Bishop, et al., Snowmobile Contributions to Mobile 
Source Emissions in Yellowstone National Park, Environmental Science 
and Technology, Vol. 35, No. 14, at 2873. Docket No. A-2000-01, 
Document No. II-A-47.

                                        Table II.D-4.--1998 Annual HC Emissions (tpy), Yellowstone National Park
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    HC
                                                                    CO
                                                                    NOX
                                                                    PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source:
  Coaches...............................................        2.69          0%       24.29          1%        0.42          0%        0.01          0%
  Autos.................................................      307.17         33%    2,242.12         54%      285.51         88%       12.20         60%
  RVs...................................................       15.37          2%      269.61          6%       24.33          7%        0.90          4%
  Snowmobiles...........................................      596.22         64%    1,636.44         39%        1.79          1%        6.07         30%
  Buses.................................................        4.96          1%       18.00          0%       13.03          4%        1.07          5%
                                                         ------------            ------------            ------------            ------------
        Total...........................................       926.4                4,190.46                  325.08                   20.25
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: National Park Service, February 2000. Air Quality Concerns Related to Snowmobile Usage in National Parks. Air Docket A-2000-01, Document No. II-
  A-44.

    The information presented in this discussion indicates that 
snowmobiles are significant emitters of pollutants that are known to 
contribute to visibility impairment in some Class I areas. Annual and 
particularly wintertime hydrocarbon emissions from snowmobiles are high 
in the five parks considered in Table II.D-4, with two parks having HC 
emissions nearly as high as Yellowstone (Rocky Mountain and Voyageurs). 
The proportion of snowmobile emissions to emissions from other sources 
affecting air quality in these parks is likely to be similar to that in 
Yellowstone.
    c. Snowmobiles and personal exposure to air toxics and CO. 
Snowmobile users can be exposed to high air toxic and CO emissions, 
both because they sit very close to the vehicle's exhaust port and 
because it is common for them to ride their vehicles on groomed trails 
where they travel fairly close behind other snowmobiles. Because of 
these riding patterns, snowmobilers breathe exhaust emissions from 
their own vehicle, the vehicle directly in front, as well as those 
farther up the trail. This can lead to relatively high personal 
exposure levels of harmful pollutants. A study of snowmobile rider CO 
exposure conducted at Grand Teton National Park showed that a 
snowmobiler riding at distances of 25 to 125 feet behind another 
snowmobiler and traveling at speeds from 10 to 40 mph can be exposed to 
average CO levels ranging from 0.5 to 23 ppm, depending on speed and 
distance. The highest CO level measured in this study was 45 ppm, as 
compared to the current 1-hour NAAQS for CO of 35 ppm.\110\ While 
exposure levels can be less if a snowmobile drives 15 feet off the 
centerline of the lead snowmobile, the exposure levels are still of 
concern. This study led to the development of an empirical model for 
predicting CO exposures from riding behind snowmobiles.
---------------------------------------------------------------------------

    \110\ Snook and Davis, 1997, ``An Investigation of Driver 
Exposure to Carbon Monoxide While Traveling Behind Another 
Snowmobile.'' Docket No. A-2000-01, Document Number II-A-35.
---------------------------------------------------------------------------

    Hydrocarbon speciation for snowmobile emissions was performed for 
the State of Montana in a 1997 report.\111\ Using the empirical model 
for CO from the Grand Teton exposure study with benzene emission rates 
from the State of Montana's emission study, benzene exposures for 
riders driving behind a single snowmobile were predicted to range from 
1.2E+02 to 1.4E+03 g/m3. Using the same model to predict 
exposures when riding at the end of a line of six snowmobiles spaced 25 
feet apart yielded exposure predictions of 3.5E+03, 1.9E+03,

[[Page 51114]]

1.3E+03, and 1.2E+03 g/m3 benzene. at 10, 20, 30, and 40 mph, 
respectively.
---------------------------------------------------------------------------

    \111\ Emissions from Snowmobile Engines Using Bio-based Fuels 
and Lubricants, Southwest Research Institute, August, 1997, at 22. 
Docket No. A-2000-01, Document Number II-A-50.
---------------------------------------------------------------------------

    The cancer risk posed to those exposed to benzene emissions from 
snowmobiles must be viewed within the broader context of expected 
lifetime benzene exposure. Observed monitoring data and predicted 
modeled values demonstrate that a significant cancer risk already 
exists from ambient concentrations of benzene for a large portion of 
the US population. The Agency's 1996 National-Scale Air Toxics 
Assessment of personal exposure to ambient concentrations of air toxic 
compounds emitted by outside sources (e.g. cars and trucks, power 
plants) found that benzene was among the five air toxics that appear to 
pose the greatest risk to people nationwide. This national assessment 
found that for approximately 50% of the US population in 1996, the 
inhalation cancer risks associated with benzene exceeded 10 in one 
million. Modeled predictions for ambient benzene from this assessment 
correlated well with observed monitored concentrations of benzene 
ambient concentrations.
    Specifically, the draft National-Scale Assessment predicted 
nationwide annual average benzene exposures from outdoor sources to be 
1.4 g/m3.\112\ In comparison, snowmobile riders and those 
directly exposed to snowmobile exhaust emissions had predicted benzene 
levels two to three orders of magnitude greater than the 1996 national 
average benzene concentrations.\113\ These elevated levels are also 
known as air toxic ``hot spots,'' which are of particular concern to 
the Agency. Thus, total annual average exposures to typical ambient 
benzene concentrations combined with elevated short-term exposures to 
benzene from snowmobiles may pose a significant risk of adverse public 
health effects to snowmobile riders and those exposed on a frequent 
basis to exhaust benzene emissions from snowmobiles. We request comment 
on this issue.
---------------------------------------------------------------------------

    \112\ National-Scale Air Toxics Assessment for 1996, EPA-453/R-
01-003, Draft, January 2001.
    \113\ Technical Memorandum, Chad Bailey, Predicted benzene 
exposures and ambient concentrations on and near snowmobile trails, 
August 17, 2001. Air Docket A-2000-01, Document No. II-B-27.
---------------------------------------------------------------------------

    Since snowmobile riders often travel in large groups, the riders 
towards the back of the group are exposed to the accumulated exhaust of 
those riding ahead. These exposure levels can continue for hours at a 
time. An additional consideration is that the risk to health from CO 
exposure increases with altitude, especially for unacclimated 
individuals. Therefore, a park visitor who lives at sea level and then 
rides his or her snowmobile on trails at high-altitude is more 
susceptible to the effects of CO than local residents.
    In addition to snowmobilers themselves, people who are active in 
proximity to the areas where snowmobilers congregate may also be 
exposed to high CO levels. An OSHA industrial hygiene survey reported a 
peak CO exposure of 268 ppm for a Yellowstone employee working at an 
entrance kiosk where snowmobiles enter the park. This level is greater 
than the NIOSH peak recommended exposure limit of 200 ppm. OSHA's 
survey also measured employees' exposures to several air toxics. 
Benzene exposures in Yellowstone employees ranged from 67-600 
g/m3, with the same individual experiencing highest CO and 
benzene exposures. The highest benzene exposure concentrations exceeded 
the NIOSH Recommended Exposure Limit of 0.1 ppm for 8-hour 
exposures.\114\
---------------------------------------------------------------------------

    \114\ U.S. Department of Labor, OSHA, Billings Area Office, 
``Industrial Hygiene Survey of Park Employee Exposures During Winter 
Use at Yellowstone National Park,'' February 19 through February 24, 
2000. Docket No. A-2000-01, Document Number II-A-37; see also 
Industrial Hygiene Consultation Report prepared for Yellowstone 
National Park by Tim Radtke, CIH, Industrial Hygienist, June 1997. 
Docket A-2000-01, Document No. A-II-41.
---------------------------------------------------------------------------

    d. Summary. For all of the reasons described in this section, we 
continue to believe it is appropriate to set emission standards for 
snowmobiles. At the national level, these engines contribute to CO 
levels in several nonattainment areas. Snowmobiles contribute 
significantly to hydrocarbon emissions that are known to contribute to 
visibility impairment in Class I areas. In addition, snowmobilers 
riding in a trail formation, as well as park attendants and other 
bystanders can experience very high levels of CO and benzene for 
relatively long periods of time. The proposed standards will help 
reduce these emissions and help alleviate these concerns.
2. Recreational Marine
    As with snowmobiles, the usage patterns of recreational marine 
engine can lead to high personal exposure levels, particularly for CO 
emissions. The U.S. Coast Guard reported cases of CO poisoning caused 
by recreational boat usage.\115\ These Coast Guard investigations into 
recreational boating accident reports between 1989 to1998 show that 57 
accidents were reported, totaling 87 injuries and 32 fatalities, that 
involved CO poisoning. An article in the Journal of the American 
Medical Association also discusses CO poisoning among recreational boat 
users.\116\ This study reports 21 incidences of CO poisoning from 
sterndrive and inboard engines; two-thirds of these incidences occurred 
when the boat was cruising.
---------------------------------------------------------------------------

    \115\ Summarized in an e-mail from Phil Cappel of the U.S. Coast 
Guard to Mike Samulski of the U.S. Environmental Protection Agency, 
October 19, 2000. Docket A-2000-01, Document No. II-A-46.
    \116\ Silvers, S., Hampton, N., ``Carbon Monoxide Poisoning 
Among Recreational Boaters,'' JAM, November 22/29, 1995, Vol 274, 
No. 20. Docket A-2000-01, Document No. 11-A-45.
---------------------------------------------------------------------------

    The CO exposure to boaters comes from three general sources. First, 
CO may enter the engine compartment and cabin spaces from leaks in the 
exhaust system. Second, boaters may be exposed to CO if they are near 
the engine when it is idling such as swimming behind the boat. Third, 
CO may be drawn into the boat when it is cruising due to a back draft 
of air into the boat known as the ``station wagon effect.'' \117\
---------------------------------------------------------------------------

    \117\ United States Coast Guard, ``Boating Safety Circular 64,'' 
December 1986. Docket A-2000-01, Document No. II-A-43.
---------------------------------------------------------------------------

3. Large SI Engines
    Exhaust emissions from applications with significant indoor use can 
expose individual operators or bystanders to dangerous levels of 
pollution. Forklifts, ice-surfacing machines, sweepers, and carpet 
cleaning equipment are examples of large industrial spark-ignition 
engines that often operate indoors or in other confined spaces. 
Forklifts alone account for over half of the engines in this category. 
Indoor use may include extensive operation in a temperature-controlled 
environment where ventilation is kept to a minimum (for example, for 
storing, processing, and shipping produce).
    The principal concern for human exposure relates to CO emissions. 
One study showed several forklifts operating on liquefied petroleum gas 
(LPG) with measured CO emissions ranging from 10,000 to 90,000 ppm (1 
to 9 percent).\118\ The threshold limit value for a time-weighted 
average 8-hour workplace exposure set by the American Conference of 
Governmental Industrial Hygienists is 25 ppm. The recommended limit 
adopted by the National Institute for Occupational Safety and Health is 
35 ppm for 8-hour exposure and maximum instantaneous exposure of 200 
ppm. While these lower numbers refer to ambient concentrations, the 
very high documented exhaust concentrations

[[Page 51115]]

would quickly exceed the ambient levels in any operation in enclosed 
areas without extraordinary ventilation.
---------------------------------------------------------------------------

    \118\ ``Warehouse Workers' Headache, Carbon Monoxide Poisoning 
from Propane-Fueled Forklifts,'' Thomas A. Fawcett, et al, Journal 
of Occupational Medicine, January 1992, p.12. Docket A-2000-01, 
Document No. II-A-36.
---------------------------------------------------------------------------

    Large SI engines operating on any fuel can have very high CO 
emission levels. While our emission modeling estimates a significantly 
lower emission rate for engines fueled by LPG relative to gasoline, the 
study described above shows clearly that individual engines that should 
have low CO emissions can, through maladjustment or normal degradation, 
reach dangerous emission levels.
    Additional exposure concerns occur at ice rinks. Numerous papers 
have identified ice-surfacing machines with spark-ignition engines as 
the source of dangerous levels of CO and NO2, both for 
skaters and for spectators.\119\ This is especially problematic for 
skaters, who breathe air in the area where pollutant concentration is 
highest, with higher respiration rates resulting from their high level 
of physical activity. This problem has received significant attention 
from the medical community.
---------------------------------------------------------------------------

    \119\ ``Summary of Medical Papers Related to Exhaust Emission 
Exposure at Ice Rinks,'' EPA Memorandum from Alan Stout to Docket A-
2000-01. Docket A-2000-01, Document No. II-A-38.
---------------------------------------------------------------------------

    In addition to CO emissions, HC emissions from all Large SI engines 
can lead to increased exposure to harmful pollutants, particularly air 
toxic emissions. Since many gasoline or dual-fuel engines are in 
forklifts that operate indoors, reducing evaporative emissions could 
have additional health benefits to operators and other personnel. Fuel 
vapors can also cause odor problems.

III. Nonroad: General Concepts

    This section describes general concepts concerning the proposed 
emission standards and the ways in which a manufacturer would show 
compliance with these standards. Clean Air Act Section 213 requires us 
to set standards that achieve the greatest degree of emission reduction 
achievable through the application of technology that will be 
available, giving appropriate consideration to cost, noise, energy, and 
safety factors. In addition to emission standards, this document 
describes a variety of proposed requirements such as applying for 
certification, labeling engines, and meeting warranty requirements to 
define a process for implementing the proposed emission-control program 
in an effective way.
    The discussions in this section are general and are meant to cover 
all the nonroad engines and vehicles that would be subject to the 
proposed standards. Refer to the discussions of specific engine 
programs, contained in Sections IV through VI, for more information 
about specific requirements for different categories of nonroad engines 
and vehicles. We request comment on all aspects of these general 
program provisions.
    This section describes general nonroad provisions related to 
certification prior to sale or introduction into commerce. Section VII 
describes several proposed compliance provisions that apply generally 
to nonroad engines, and Section VIII similarly describes general 
testing provisions.

A. Scope of Application

    As noted in Section I.C.1, this proposal covers recreational marine 
diesel engines, nonroad industrial SI engines rated over 19 kW, and 
recreational vehicles introduced into commerce in the United States. 
The following sections describe generally when emission standards apply 
to these products. Refer to the specific program discussion below for 
more information about the scope of application and timing of the 
proposed standards.
1. Do the Standards Apply to All Engines and Vehicles or Only to New 
Engines and Vehicles?
    The scope of this proposal is broadly set by Clean Air Act section 
213(a)(3), which instructs us to set emission standards for new nonroad 
engines and new nonroad vehicles. Generally speaking, the proposed rule 
is intended to cover all new engines and vehicles in the categories 
listed above (including any associated equipment or vessels).\120\ Once 
the emission standards apply to a group of engines or vehicles, 
manufacturers must get a certificate of conformity from us before 
selling them in the United States.\121\ This includes importation and 
any other means of introducing engines and vehicles into commerce. We 
also require equipment manufacturers that install engines from other 
companies to install only certified engines once emission standards 
apply. The certificate of conformity (and corresponding engine label) 
provide assurance that manufacturers have met their obligation to make 
engines that meet emission standards over the useful life we specify in 
the regulations.
---------------------------------------------------------------------------

    \120\ For some categories, we are proposing vehicle-based or 
vessel-based standards. In these cases, the term ``engine'' in this 
document applies equally to the vehicles or vessels.
    \121\ The term ``manufacturer'' includes any individual or 
company introducing engines into commerce in the United States.
---------------------------------------------------------------------------

2. How Do I Know if My Engine or Equipment Is New?
    We are proposing to define ``new'' consistent with previous 
rulemakings. Under the proposed definition, a nonroad engine (or 
nonroad equipment) is considered new until its title has been 
transferred to the ultimate purchaser or the engine has been placed 
into service. This proposed definition would apply to both engines and 
equipment, so the nonroad equipment using these engines, including all-
terrain vehicles, snowmobiles, off-highway motorcycles, and other land-
based nonroad equipment would be considered new until their title has 
been transferred to an ultimate buyer. In Section III.B.1 we describe 
how to determine the model year of individual engines and vehicles.
    To further clarify the proposed definition of new nonroad engine, 
we are proposing to specify that a nonroad engine, vehicle, or 
equipment is placed into service when it is used for its intended 
purpose. We are therefore proposing that an engine subject to the 
proposed standards is used for its functional purpose when it is 
installed on an all-terrain vehicle, snowmobile, off-highway 
motorcycle, marine vessel, or other piece of nonroad equipment. We need 
to make this clarification because some engines are made by modifying a 
highway or land-based nonroad engine that has already been installed on 
a vehicle or other piece of equipment. For example, someone can install 
an engine in a recreational marine vessel after it has been used for 
its functional purpose as a land-based highway or nonroad engine. We 
believe this is a reasonable approach because the practice of adapting 
used highway or land-based nonroad engines may become more common if 
these engines are not subject to the standards in this proposal.
    In summary, an engine would be subject to the proposed standards if 
it is:

 Freshly manufactured, whether domestic or imported; this may 
include engines produced from engine block cores
 Installed for the first time in nonroad equipment after having 
powered a car or a category of nonroad equipment subject to different 
emission standards
 Installed in new nonroad equipment, regardless of the age of 
the engine
 Imported (new or used)
3. When Do Imported Engines Need To Meet Emission Standards?
    The proposed emission standards would apply to all new engines that 
are used in the United States. According to

[[Page 51116]]

Clean Air Act section 216, ``new'' includes engines that are imported 
by any person, whether freshly manufactured or used. Thus, the proposed 
program would include engines that are imported for use in the United 
States, whether they are imported as loose engines or if they are 
already installed on a marine vessel, recreational vehicle, or other 
piece of nonroad equipment, built elsewhere. All imported engines would 
need an EPA-issued certificate of conformity to clear customs, with 
limited exemptions (as described below).
    If an engine or marine vessel, recreational vehicle, or other piece 
of nonroad equipment that was built after emission standards take 
effect is imported without a currently valid certificate of conformity, 
we would still consider it to be a new engine, vehicle, or vessel. This 
means it would need to comply with the applicable emission standards. 
Thus, for example, a marine vessel manufactured in a foreign country in 
2007, then imported into the United States in 2010, would be considered 
``new.'' The engines on that piece of equipment would have to comply 
with the requirements for the 2007 model year, assuming no other 
exemptions apply. This provision is important to prevent manufacturers 
from avoiding emission standards by building vessels abroad, 
transferring their title, and then importing them as used vessels.
    With regard to recreational vehicles, the United States Customs 
Service currently allows foreign nationals traveling with their 
personal automobiles, trailers, aircraft, motorcycles, or boats to 
import such vehicles without having to pay a tariff, so long as they 
are used in the United States only for the transportation of such 
person.\122\ We propose to use this approach in our regulation of 
emissions from recreational vehicles (snowmobiles, off-highway 
motorcycles, and all-terrain vehicles). We propose to allow 
noncompliant recreational vehicles that are the personal property of 
foreign nationals to be imported into the United States as long as the 
foreign national bringing them into the country intends to use them 
only for his or her recreational purposes and they are not left here 
when the person leaves the country (they are either taken back or 
destroyed). In other words, such recreational vehicles would not be 
considered ``new'' for the purpose of determining whether they must 
comply with the proposed emission limits. We propose that a time limit 
of one year on this exemption so that recreational vehicles imported 
for more than that period of time would be considered imported, and 
therefore ``new'' and subject to the proposed emission limits. We are 
also proposing that this time period cannot be extended. This time 
limit is designed to prevent a person from using the exemption to 
effectively circumvent the standards.
---------------------------------------------------------------------------

    \122\ Harmonized Tariff Schedule of the United States (2001) 
(Rev. 1), subheading 9804.00.35. A copy of this document is included 
in Air Docket A-2000-01, at Document No. II-A-82.
---------------------------------------------------------------------------

    This exemption generally would not apply to any commercial engines 
that would be subject to emission standards. To import noncomplying 
engines for commercial applications, the importer would have to meet 
the requirements for a different exemption, as described in Section 
VII.
4. Do the Standards Apply to Exported Engines or Vehicles?
    Engines or vehicles intended for export would generally not be 
subject to the requirements of the proposed emission-control program. 
However, engines that are exported and subsequently re-imported into 
the United States would need to be certified. For example, this would 
be the case when a foreign company purchases engines manufactured in 
the United States for installation on a marine vessel, recreational 
vehicle, or other nonroad equipment for export back to the United 
States. Those engines would be subject to the emission standards that 
apply on the date the engine was originally manufactured. If the engine 
is later modified and certified (or recertified), the engine is subject 
to emission standards that apply on the date of the modification. So, 
for example, foreign boat builders buying U.S.-made engines without 
recertifying the engines will need to make sure they purchase complying 
engines for the products they sell in the U.S.
5. Are There Any New Engines or Vehicles That Would Not Be Covered?
    We are proposing to extend our basic nonroad exemptions to the 
engines and vehicles covered by this proposal. These include the 
testing exemption, the manufacturer-owned exemption, the display 
exemption, and the national security exemption. These exemptions are 
described in more detail in Section VII.C.
    In addition, the Clean Air Act does not consider stationary engines 
or engines used solely for competition to be nonroad engines, so the 
proposed emission standards do not apply to them. Refer to the program 
discussions below for a discussion of how these exclusions apply for 
different categories of engines.

B. Emission Standards and Testing

1. How Does EPA Determine the Emission Standards?
    Our general goal in designing the proposed standards is to develop 
a program that will achieve significant emission reductions. We are 
guided by Clean Air Act section 213(a)(3), which instructs us to 
``achieve the greatest degree of emission reduction achievable through 
the application of technology the Administrator determines will be 
available for the engines or vehicles to which such standards apply, 
giving appropriate consideration to the cost of applying such 
technology within the period of time available to manufacturers and to 
noise, energy, and safety factors associated with the application of 
such technology.'' The Act also instructs us to first consider 
standards equivalent in stringency to standards for comparable motor 
vehicles or engines (if any) regulated under section 202, taking into 
consideration technological feasibility, costs, and other factors.
    Engines subject to the proposed exhaust emission standards would 
have to meet the standards based on measured emissions of specified 
pollutants such as NOX, HC, or CO, though not all engines 
will have standards for each pollutant. Diesel engines generally must 
also meet a PM emission standard. In addition, there may be 
requirements for crankcase or evaporative emissions, as described 
below.
    The proposed emission standards would be effective on a model-year 
basis. We are proposing to define model year much like we do for 
passenger cars. It would generally mean either the calendar year or 
some other annual production period based on the manufacturer's 
production practices. For example, manufacturers could start selling 
2006 model year engines as early as January 2, 2005, as long as the 
production period extends until at least January 1, 2006. All of a 
manufacturer's engines from a given model year would have to meet 
emission standards for that model year. For example, manufacturers 
producing new engines in the 2006 model year would need to comply with 
the 2006 standards. Refer to the individual program discussions below 
or the regulations for additional information about model year periods, 
including how to define what model year means in less common scenarios, 
such as installing used engines in new equipment.

[[Page 51117]]

2. What Standards Would Apply to Crankcase and Evaporative Emissions?
    Due to blow-by of combustion gases and the reciprocating action of 
the piston, exhaust emissions can accumulate in the crankcase of four-
stroke engines. Uncontrolled engine designs route these vapors directly 
to the atmosphere, where they contribute to ambient levels of these 
pollutants. We have long required that automotive engines prevent 
emissions from their crankcases. Manufacturers generally do this by 
routing crankcase vapors through a valve into the engine's air intake 
system. We are proposing to require that engines prevent crankcase 
emissions. We request comment on this proposed requirement for 
individual types of engines, as described in those sections below.
    For industrial spark-ignition engines, we are proposing standards 
to limit evaporative emissions. Evaporative emissions result from 
heating gasoline (or other volatile fuels) in a tank that is vented to 
the atmosphere. See Section IV for additional information.
3. What Duty Cycles Is EPA Proposing for Emission Testing?
    Testing an engine for exhaust emissions typically consists of 
exercising it over a prescribed duty cycle of speeds and loads, 
typically using an engine or chassis dynamometer. The duty cycle used 
to measure emissions for certification, which simulates operation in 
the field, is critical in evaluating the likely emissions performance 
of engines designed to emission standards.
    Steady-state testing consists of engine operation for an extended 
period at several speed-load combinations. Associated with these test 
points are weighting factors that allow calculation of a single 
weighted-average steady-state emission level in g/kW. Transient testing 
involves a continuous trace of specified engine or vehicle operation; 
emissions are collected over the whole testing period for a single mass 
measurement.
    See Section VIII.C for a discussion of how we define maximum test 
speed and intermediate speed for engine testing. Refer to the program 
discussions below for more information about the type of duty cycle 
required for testing the various engines and vehicles.
4. How Do Adjustable Engine Parameters Affect Emission Testing?
    Many engines are designed with components that can be adjusted for 
optimum performance under changing conditions, such as varying fuel 
quality, high altitude, or engine wear. Examples of adjustable 
parameters include spark timing, idle speed setting, and fuel injection 
timing. While we recognize the need for this practice, we are also 
concerned that engines maintain a consistent level of emission control 
for the whole range of adjustability. We are therefore proposing to 
require manufacturers to show that their engines meet emission 
standards over the full adjustment range.
    Manufacturers would also have to provide a physical stop to prevent 
adjustment outside the established range. Operators would then be 
prohibited by the anti-tampering provisions from adjusting engines 
outside this range. Refer to the proposed regulatory text for more 
information about adjustable engine parameters. See especially the 
proposed sections 40 CFR 1048.115 for industrial SI engines and 40 CFR 
1051.115 for recreational vehicles.
5. What Are Voluntary Low-Emission Engines and Blue Sky Standards?
    Several state and environmental groups and manufacturers of 
emission controls have supported our efforts to develop incentive 
programs to encourage the use of engine technologies that go beyond 
federal emission standards. Some companies have already significantly 
developed these technologies. In the final rule for land-based nonroad 
diesel engines, we included a program of voluntary standards for low-
emitting engines, referring to these as ``Blue Sky Series'' engines (63 
FR 56967, October 23, 1998). We included similar programs in several of 
our other nonroad rules, including commercial marine diesel. The 
general purposes of such programs are to provide incentives to 
manfuacturers to produce clean products as well as create market 
choices and opportunities for environmental information for consumers 
regarding such products. The voluntary aspects of these programs, which 
in part provides an incentive for manufacturers willing to certify 
their products to more stringent standards than necessary, is an 
important part of the overall application of ``Blue Sky Series'' 
programs.
    We are proposing voluntary Blue Sky Series standards for many of 
the engines subject to this proposal. Creating a program of voluntary 
standards for low-emitting engines, including testing and durability 
provisions to help ensure adequate in-use performance, will be a step 
forward in advancing emission-control technologies. While these are 
voluntary standards, they become binding once a manufacturer chooses to 
participate. EPA certification will therefore provide protection 
against false claims of environmentally beneficial products. For the 
program to be most effective, however, incentives should be in place to 
motivate the production and sale of these engines. We solicit ideas 
that could encourage the creation of these incentive programs by users 
and state and local governments. We also request comment on additional 
measures we could take to encourage development and introduction of 
these engines. Finally, we request comment on the Blue Sky Series 
approach in general as it would apply to the engines covered by this 
proposed rule.

C. Demonstrating Compliance

    We are proposing a compliance program to accompany emission 
standards. This consists first of a process for certifying engine 
models. In addition to certification testing, we are proposing several 
provisions to ensure that emission-control systems continue to function 
over long-term operation in the field. Most of these certification and 
durability provisions are consistent with previous rulemakings for 
other nonroad engines. Refer to the discussion of the specific programs 
below for additional information about these requirements for each 
engine category.
1. How Would I Certify My Engines?
    We are proposing a certification process similar to that already 
adopted for other engines. Manufacturers generally test representative 
prototype engines and submit the emission data along with other 
information to EPA in an application for a Certificate of Conformity. 
If we approve the application, then the manufacturer's Certificate of 
Conformity allows the manufacturer to produce and sell the engines 
described in the application in the U.S.
    We are proposing that manufacturers certify their engine models by 
grouping them into engine families. Under this approach, engines 
expected to have similar emission characteristics would be classified 
in the same engine family. The engine family definition is fundamental 
to the certification process and to a large degree determines the 
amount of testing required for certification. The proposed regulations 
include specific engine characteristics for grouping engine families 
for each category of engines. To address a manufacturer's unique 
product mix, we may approve using broader or narrower engine families.

[[Page 51118]]

    Engine manufacturers are generally responsible to build engines 
that meet the emission standards over each engine's useful life. The 
useful life we adopt by regulation is intended to reflect the period 
during which engines are designed to properly function without being 
remanufactured. Useful life values, which are expressed in terms of 
years or amount of operation (in hours or kilometers), vary by engine 
category, as described in the following sections. Consistent with other 
recent EPA programs, we would generally consider this useful life value 
in amount of operation to be a minimum value and would require 
manufacturers to comply for a longer period in those cases where they 
design their engines to operate longer than the minimum useful life. As 
proposed, manufacturers would be required to estimate the rate of 
deterioration for each engine family over its useful life. 
Manufacturers would show that each engine family meets the emission 
standards after incorporating the estimated deterioration in emission 
control.
    The emission-data engine is the engine from an engine family that 
will be used for certification testing. To ensure that all engines in 
the family meet the standards, we are proposing that manufacturers 
select the engine most likely to exceed emission standards in a family 
for certification testing. In selecting this ``worst-case'' engine, the 
manufacturer uses good engineering judgment. Manufacturers would 
consider, for example, all engine configurations and power ratings 
within the engine family and the range of installed options allowed). 
Requiring the worst-case engine to be tested ensures that all engines 
within the engine family are complying with emission standards.
    We are proposing to require manufacturers to include in their 
application for certification the results of all emission tests from 
their emission-data engines, including any diagnostic-type measurements 
(such as ppm testing) and invalidated tests. This complete set of test 
data ensures that the valid tests that form the basis of the 
manufacturer's application are a robust indicator of emission-control 
performance, rather than a spurious or incidental test result. We 
request comment on these data-reporting requirements.
    Clean Air Act section 206(h) specifies that test procedures for 
certifying engines (including the test fuel) should adequately 
represent in-use operation. We are proposing test fuel specifications 
intended to represent in-use fuels. Engines would have to meet the 
standards on fuels with properties anywhere in the range of proposed 
test fuel specifications. The test fuel is generally to be used for all 
testing associated with the regulations proposed in this document, 
including certification, production-line testing, and in-use testing. 
Refer to the program discussions below for a discussion of the test 
fuel proposed for different categories of engines.
    We are proposing to require engine manufacturers to give engine 
buyers instructions for properly maintaining their engines. We are 
including limitations on the frequency of scheduled maintenance that a 
manufacturer may specify for emission-related components to help ensure 
that emission-control systems don't depend on an unreasonable 
expectation of maintenance in the field. These maintenance limits would 
also apply during any service accumulation that a manufacturer may do 
to establish deterioration factors. This approach is common to all our 
engine programs. It is important to note, however, that these 
provisions would not limit the maintenance an operator could perform. 
It would merely limit the maintenance that operators would be expected 
to perform on a regularly scheduled basis. Refer to the discussion of 
the specific programs below for additional information about the 
allowable maintenance intervals for each category of engines.
    Once an engine family is certified, we would require every engine a 
manufacturer produces from the engine family to have an engine label 
with basic identifying information. We request comment on the proposed 
requirements for the design and content of engine labels, which are 
detailed in Sec. 1048.135 and Sec. 1051.135 of the proposed regulation 
text.
2. What Warranty Requirements Apply to Certified Engines?
    Consistent with our current emission-control programs, we are 
proposing that manufacturers provide a design and defect warranty 
covering emission-related components. As required by the Clean Air Act, 
the proposed regulations would require that the warranty period must be 
longer than the minimum period we specify if the manufacturer offers a 
longer mechanical warranty for the engine or any of its components; 
this includes extended warranties that are available for an extra 
price. See the proposed regulation language for a description of which 
components are emission-related.
    If an operator makes a valid warranty claim for an emission-related 
component during the warranty period, the engine manufacturer is 
generally obligated to replace the component at no charge to the 
operator. The engine manufacturer may deny warranty claims if the 
operator failed to do prescribed maintenance that contributed to the 
warranty claim.
    We are also proposing a defect reporting requirement that applies 
separate from the emission-related warranty (see Section VII.F). In 
general, defect reporting applies when a manufacturer discovers a 
pattern of component failures, whether that information comes from 
warranty claims, voluntary investigation of product quality, or other 
sources.
3. Can I Meet Standards With Emission Credits?
    Many of our emission-control programs have a voluntary emission-
credit program to facilitate implementation of emission controls. An 
emission-credit program is an important factor we take into 
consideration in setting emission standards that are appropriate under 
Clean Air Act section 213. An emission-credit program can reduce the 
cost and improve the technological feasibility of achieving standards, 
helping to ensure the attainment of the standards earlier than would 
otherwise be possible. Manufacturers gain flexibility in product 
planning and the opportunity for a more cost-effective introduction of 
product lines meeting a new standard. Emission-credit programs also 
create an incentive for the early introduction of new technology, which 
allows certain engine families to act as trailblazers for new 
technology. This can help provide valuable information to manufacturers 
on the technology before they apply the technology throughout their 
product line. This early introduction of clean technology improves the 
feasibility of achieving the standards and can provide valuable 
information for use in other regulatory programs that may benefit from 
similar technologies.
    Emission-credit programs may involve averaging, banking, or 
trading. Averaging would allow a manufacturer to certify one or more 
engine families at emission levels above the applicable emission 
standards, as long as the increased emissions are offset by one or more 
engine families certified below the applicable standards. The over-
complying engines generate credits that are used by the under-complying 
engines. Compliance is determined on a total mass emissions basis to 
account for differences in production volume, power and useful life 
among engine families. The average of all emissions

[[Page 51119]]

for a particular manufacturer's production must be at or below that 
level of the applicable emission standards. This calculation generally 
factors in sales-weighted average power, production volume, useful 
life, and load factor. Banking and trading would allow a manufacturer 
to generate emission credits and bank them for future use in its own 
averaging program in later years or sell them to another company.
    In general, a manufacturer choosing to participate in an emission-
credit program would certify each participating engine family to a 
Family Emission Limit. In its certification application, a manufacturer 
would determine a separate Family Emission Limit for each pollutant 
included in the emission-credit program. The Family Emission Limit 
selected by the manufacturer becomes the emission standard for that 
engine family. Emission credits are based on the difference between the 
emission standard that applies and the Family Emission Limit. We would 
expect the manufacturer to meet the Family Emission Limit for all 
emission testing. At the end of the model year, manufacturers would 
generally need to show that the net effect of all their engine families 
participating in the emission-credit program is a zero balance or a net 
positive balance of credits. A manufacturer could generally choose to 
include only a single pollutant from an engine family in the emission-
credit program or, alternatively, to establish a Family Emission Limit 
for each of the regulated pollutants.
    An alternative approach to requiring manufacturers to choose Family 
Emission Limits would be for us to create a discrete number of emission 
levels or ``bins'' above and below the proposed standard that 
manufacturers could certify to. These bin levels would then replace the 
Family Emission Levels in the credit calculations. We request comment 
on whether we should consider this approach for the engines covered by 
this proposal. The advantage of bins are that they can be defined by 
step changes in technology, which gives more assurance of emission 
reduction than Family Emission Limits which can change slightly with 
only marginal changes to the engine.
    Refer to the program discussions below for more information about 
emission-credit provisions for individual engine categories. We request 
comment on all aspects of the emission-credit programs discussed in 
this proposal. In particular, we request comment on the structure of 
the proposed emission-credit programs and how the various provisions 
may affect manufacturers' ability to utilize averaging, banking, or 
trading to achieve the desired emission-reductions in the most 
efficient and economical way.
4. What Are the Proposed Production-Line Testing Requirements?
    We are proposing production-line testing for recreational marine 
diesel engines, recreational vehicles, and Large SI engines. According 
to these requirements, manufacturers would routinely test production-
line engines to help ensure that newly assembled engines control 
emissions at least as well as the emission-data engines tested for 
certification. Production-line testing serves as a quality-control 
step, providing information to allow early detection of any problems 
with the design or assembly of freshly manufactured engines. This is 
different than selective enforcement auditing, in which we would give a 
test order for more rigorous testing for production-line engines in a 
particular engine family (see Section VII.E). Production-line testing 
requirements are already common to several categories of engines as 
part of their emission-control program.
    A manufacturer's liability under the production-line testing 
program is limited to the test engine and any future production. If an 
engine fails to meet an emission standard, the manufacturer must modify 
it to bring that specific engine into compliance. If too many engines 
exceed emission standards, the engine family is determined to be in 
noncompliance and the manufacturer will need to correct the problem for 
future production. This correction may involve changes to assembly 
procedures or engine design, but the manufacturer must, in any case, do 
sufficient testing to show that the engine family complies with 
emission standards.
    The proposed production-line testing programs would depend on the 
Cumulative Sum (CumSum) statistical process for determining the number 
of engines a manufacturer needs to test (see the proposed regulations 
for the specific calculation methodology). Each manufacturer selects 
engines randomly at the beginning of a new sampling period. If engines 
must be tested at a facility where final assembly is not yet completed, 
manufacturers must randomly select engine components and assemble the 
test engine according to their established assembly instructions. A 
sampling period may be a quarter or a calendar year, depending 
generally on the size of the engine family. The Cumulative Sum program 
uses the emission results to calculate the number of tests required for 
the remainder of the sampling period to reach a pass or fail 
determination. If tested engines have relatively high emissions, the 
statistical sampling method calls for an increased number of tests to 
show that the engine family meets emission standards. The remaining 
number of tests is recalculated after the manufacturer tests each 
engine. Engines selected should cover the broadest range of production 
configurations possible. Tests should also be distributed evenly 
throughout the sampling period to the extent possible.
    Under the Cumulative Sum approach, individual engines can exceed 
the emission standards without bringing the whole engine family into 
noncompliance. Note, however, that we propose to require manufacturers 
to adjust or repair every failing engine and retest it to show that it 
meets the emission standards. Note also that all production-line 
emission measurements must be included in the periodic reports to us. 
This includes any type of screening or surveillance tests (including 
ppm measurements), all data points for evaluating whether an engine 
controls emissions ``off-cycle,'' and any engine tests that exceed the 
minimum required level of testing.
    We are proposing to further reduce the testing requirements for 
engine families that consistently meet emission standards. For engine 
families with no production-line tests exceeding emission standards for 
two consecutive years, the manufacturer may request a reduced testing 
rate. The minimum testing rate is one test per engine family for one 
year. Our approval for a reduced testing rate would apply only for a 
single model year.
    As we have concluded in other engine programs, some manufacturers 
may have unique circumstances that call for different methods to show 
that production engines comply with emission standards. We therefore 
propose to allow a manufacturer to suggest an alternate plan for 
testing production-line engines, as long as the alternate program is as 
effective at ensuring that the engines will comply. A manufacturer's 
petition to use an alternate plan should address the need for the 
alternative and should justify any changes from the regular testing 
program. The petition must also describe in detail the equivalent 
thresholds and failure rates for the alternate plan. If we approved the 
plan, we would use these criteria to determine when an engine family 
would become noncompliant. It is important to note that this allowance 
is intended only as a flexibility, and is not intended

[[Page 51120]]

to affect the stringency of the standards or the production-line 
testing program.
    Refer to the specific program discussions below for additional 
information about production-line testing for different types of 
engines.

D. Other Concepts

1. What Are the Proposed Emission-Related Installation Instructions?
    For manufacturers selling loose engines to equipment manufacturers, 
we are proposing to require the engine manufacturer to develop a set of 
emission-related installation instructions. This would include anything 
that the installer would need to know to ensure that the engine 
operates within its certified design configuration. For example, the 
installation instructions could specify a total capacity needed from 
the engine cooling system, placement of catalysts after final assembly, 
or specification of parts needed to control evaporative emissions. We 
would approve the installation instructions as part of the 
certification process. If equipment manufacturers fail to follow the 
established emission-related installation instructions, we would 
consider this tampering, which could subject them to significant civil 
penalties. Refer to the program discussions below for more information 
about specific provisions related to installation instructions.
2. What Is Consumer-Choice Labeling?
    California ARB has recently proposed consumer/environmental label 
requirements for outboard and personal-watercraft engines. Under this 
concept, manufacturers would label their engines or vehicles based on 
their certified emission level. California has proposed three different 
labels to differentiate varying degrees of emission control--one for 
meeting the EPA 2006 standard, one for being 20 percent lower, and one 
for being 65 percent below. More detail on this concept is provided in 
the docket.\123\
---------------------------------------------------------------------------

    \123\ ``Public Hearing to Consider Amendments to the Spark-
Ignition Marine Engine Regulations,'' Mail Out #MSC 99-15, June 22, 
1999 (Docket A-2000-01, Document II-A-27).
---------------------------------------------------------------------------

    We are considering a similar approach to labeling the engines 
subject to this proposal. This would apply especially to consumer 
products. Consumer-choice labeling would give people the opportunity to 
consider varying emission levels as a factor in choosing specific 
models. This may also give the manufacturer an incentive to produce 
more of their cleaner engine models. A difficulty in designing a 
labeling program is in creating a scheme that communicates information 
clearly and simply to consumers. Given the very different emission 
levels expected from the various engines, it would be difficult to 
create a consistent set of labels for different engines. Also, we are 
concerned that other organizations could use the labeling provisions to 
mandate certain levels of emission control, rather than relying on 
consumer choice as a market-based incentive. We request comment on this 
approach for recreational marine engines and vessels and for 
recreational vehicles.
    An alternative to the promotional-type label adopted by California 
ARB would be an approach that simply identifies an engine's certified 
emission levels on the emission-control label. This ``informational 
label'' could be used with or without defining voluntary emission 
standards. This would not provide a standardized way for manufacturers 
to promote their cleanest products, but it would give interested 
consumers the ability to make informed choices based on a vehicle's 
certified emission levels. We are proposing this approach of requiring 
an engine's certified emission levels to be on the emission-control 
label for engines and vehicles certified to voluntary low emission or 
Blue Sky standards. We request comment on this approach and whether we 
should extend this requirement to all vehicles and engines, not just 
those complying with voluntary low emission standards. Also, we request 
comment on the relative advantages of the different approaches to 
consumer-choice labeling just discussed.
3. Are There Special Provisions for Small Manufacturers of These 
Engines and Vehicles?
    The Regulatory Flexibility Act, 5 U.S.C. 601-612, was amended by 
the Small Business Regulatory Enforcement Act of 1996 (SBREFA), Public 
Law 104-121, to ensure that concerns regarding small entities are 
adequately considered during the development of new regulations that 
affect them. The scope of this proposal includes many engine and 
vehicle manufacturers that have not been subject to our regulations or 
certification process. Many of these manufacturers are small businesses 
for which a typical regulatory program may be very burdensome. The 
sections describing the proposed emission-control program include 
discussion of proposed special compliance provisions designed to 
address this for the different engine categories. Section XI.B gives an 
overview of the inter-agency process in which we developed these small-
volume provisions.

IV. Large SI Engines

A. Overview

    This section applies to most nonroad spark-ignition engines rated 
over 19 kW (``Large SI engines''). The companies producing Large SI 
engines are typically subsidiaries of automotive companies. In most 
cases, these companies modify car and truck engines for industrial 
applications. However, the Large SI industry has historically taken a 
much less centralized approach to designing and producing engines. 
Engine manufacturers often sell dressed engine blocks without manifolds 
or fuel systems. Fuel system suppliers have played a big role in 
designing and calibrating nonroad engines, sometimes participating 
directly in engine assembly. Several equipment manufacturers, mostly 
forklift producers, also play the role of an engine manufacturer by 
calibrating engine models and completing engine assembly.
    The proposed emission standards would achieve emission reductions 
of about 90 percent for CO, 85 percent for NOX, and 70 
percent for HC. Since the emission standards are based on engine 
testing with broadly representative duty cycles, these estimated 
reductions apply to all types of equipment using these engines. 
Reducing Large SI engine emissions will be especially valuable to 
individuals operating these engines in enclosed areas.
    The cost of applying the anticipated emission-control technology to 
these engines is offset by much greater cost savings from reduced fuel 
consumption over the engines' operating lifetime. The large estimated 
fuel and maintenance savings relative to the estimated incremental cost 
of producing low-emitting engines raise the question of why normal 
market forces have failed to induce manufacturers to design and sell 
engines with emission-control technologies on the basis of the expected 
performance improvements. As described in Chapter 5 of the Draft 
Regulatory Support Document, we believe this is largely accounted for 
by the difficulty of equipment purchasers to justify increased capital 
spending on industrial machines, even with the potential for net 
savings over the lifetime of the equipment. This in turn prevents 
manufacturers from developing or implementing technologies in light of 
the uncertain demand. We request comment on the market dynamics that 
would prevent the development of and demand for cost-saving 
technologies.
    This section describes the proposed requirements that would apply 
to engine manufacturers. See Section III for

[[Page 51121]]

a description of our general approach to regulating nonroad engines and 
how manufacturers show that they meet emission standards. See Section 
VII for additional proposed requirements for engine manufacturers, 
equipment manufacturers, and others.

B. Large SI Engines Covered by This Proposal

    Large SI engines covered in this section power nonroad equipment 
such as forklifts, sweepers, pumps, and generators. This would include 
marine auxiliary engines, but does not include marine propulsion 
engines or engines used in recreational vehicles (snowmobiles, off-
highway motorcycles, and all-terrain vehicles). These other nonroad 
applications are addressed elsewhere in this document.
    Even though some aircraft use engines similar to the Large SI 
engines described in this proposal, we are not proposing emission 
standards for aircraft. Aircraft are covered under a separate part of 
the Clean Air Act. EPA's current aircraft regulations define aircraft 
as needing airworthiness certification from the Federal Aviation 
Administration. However, neither ultra-light airplanes nor blimps are 
governed by emission standards under our aircraft regulations. Ultra-
light airplanes are exempt from the airworthiness-certification 
requirements in 14 CFR part 91. In contrast, blimps are subject to 
airworthiness certification, but EPA's emission standards for aircraft 
do not apply to them. Blimps are very likely to be able to use 
conventional land-based engines for propulsion and navigation. Our 
proposed definition of aircraft in these regulations would exclude all 
aircraft from emission standards, including aircraft that do not 
receive an airworthiness certificate from FAA. We may address this 
issue in a separate Federal Register notice.
    This proposal applies only to spark-ignition engines. Our most 
recent rulemaking for nonroad diesel engines finalized a definition of 
``compression-ignition'' that was intended to address the status of 
alternative-fuel engines (63 FR 56968, October 23, 1998). We are 
proposing to adopt updated definitions consistent with those already 
established in previous rulemakings to clarify that all reciprocating 
internal combustion engines are either spark-ignition or compression-
ignition. We request comment on whether we should revise the 
definitions that differentiate between these types of engines.
    Several types of engines are excluded or exempted from the proposed 
requirements. The following sections describe the types of special 
provisions that apply uniquely to nonrecreational spark-ignition 
engines rated over 19 kW. Section VII.C covers several additional 
exemptions that apply generally across programs.
1. Stationary Engine Exclusion
    Consistent with the Clean Air Act, we do not treat stationary 
engines as nonroad engines, so the proposed emission standards would 
not apply to engines used in stationary applications. In general, an 
engine is considered stationary if it will be either installed in a 
fixed position or if it will be a portable (or transportable) engine 
operating in a single location for at least one year. We are proposing 
a requirement that these stationary engines have an engine label 
identifying their excluded status. This would be especially valuable 
for importing excluded engines without complication from U.S. Customs 
officials. It would also help us ensure that such engines are 
legitimately excluded from the emission standards proposed in this 
document.
2. Exclusion for Engines Used Solely for Competition
    The Clean Air Act also does not consider engines used solely for 
competition to be nonroad engines. We would normally include this 
exclusion directly in the regulations. For Large SI engines, however, 
it seems unlikely that there would be any need for an explicit 
treatment of competition engines in the regulations. Any applications 
involving competition with spark-ignition engines would likely fall 
under the proposed program for recreational vehicles, which has an 
extensive treatment of competition engines. We request comment on the 
need for more detailed consideration of Large SI engines that may be 
used solely for competition.
3. Motor Vehicle Engine Exemption
    In some cases an engine manufacturer may want to modify a certified 
automotive engine for nonroad use to sell the engine without 
recertifying it as a Large SI engine. We propose to allow for this, as 
long as the manufacturer makes no changes to the engine that could 
affect its exhaust or evaporative emissions. We propose to require 
annual reporting for companies that use this exemption, including a 
list of engine models from each company. Manufacturers must generally 
meet all the requirements from 40 CFR part 86 that would apply if the 
engine were used in a motor vehicle. Section 1048.605 of the proposed 
regulations describes the qualifying criteria and responsibilities in 
greater detail.
    In addition, a vehicle manufacturer may want to produce vehicles 
certified to highway emission standards for nonroad use. We propose to 
allow this, as long as there is no change in the vehicle's exhaust or 
evaporative emission-control systems.
4. Lawn and Garden Engine Exemption
    Most Large SI engines have a total displacement greater than one 
liter. The design and application of the few Large SI engines currently 
being produced with displacement less than one liter are very similar 
to those of engines rated below 19 kW, which are typically used for 
lawn and garden applications. As described in the most recent 
rulemaking for these smaller engines, we propose that manufacturers may 
certify engines between 19 and 30 kW with total displacement of one 
liter or less to the requirements we have already adopted in 40 CFR 
part 90 for engines below 19 kW (see 65 FR 24268, April 25, 2000). 
These engines would then be exempt from the requirements proposed in 
this document. This approach would allow manufacturers of small air-
cooled engines to certify their engines rated between 19 and 30 kW with 
the program adopted for the comparable engines with slightly lower 
power ratings. This would also be consistent with the provisions 
adopted by California ARB.
    We are proposing the 30-kW cap to address our concern that treating 
all engines under one liter as Small SI engines may be inadequate. For 
example, lawn and garden engines generally don't use turbochargers or 
other technologies to achieve very high power levels. However, it may 
be possible for someone to design an engine under one liter with 
unusually high power, which would more appropriately be grouped with 
other Large SI engines with similar power capability rather than with 
Small SI engines. Motorcycles, for example, may produce 120 kW from a 
750 cc (0.75 liter) engine. The 30-kW maximum power rating to qualify 
for treatment as Small SI engines represents a reasonable maximum power 
output that is possible from SI engines under one liter with 
technologies typical of lawn and garden engines. We request comment on 
the suggested power threshold and on any other approaches to addressing 
the issue of which standards should apply to engines in this 
intermediate size and power range.
    We are proposing a temporary expansion of the lawn and garden 
exemption for small-volume manufacturers, as described in Section IV.E.

[[Page 51122]]

    Technological, economic and environmental issues associated with 
the few engine models with rated power over 19 kW, but with 
displacement at or below 1 liter were previously analyzed in the 
rulemaking for Small Nonroad SI engines. This proposal therefore does 
not specifically address the provisions applying to them or repeat the 
estimated impacts of adopting emission standards.
    Conversely, we are aware that some engines rated below 19 kW may be 
part of a larger family of engine models that includes engines rated 
above 19 kW. This may include, for example, three- and four-cylinder 
engine models that are otherwise identical. To avoid the need to 
separate these engines into separate engine families (certified under 
completely different control programs), we propose to allow any engine 
rated under 19 kW to certify to the more stringent Large SI emission 
standards. Such an engine would then be exempt from the requirements of 
40 CFR part 90. Since manufacturers exercising this option would be 
voluntarily meeting a more stringent emission standard, this does not 
affect our earlier conclusions about the appropriate standards for 
engines rated under 19 kW.
    We may also consider applying the Large SI emission standards to 
these smaller engines on a mandatory basis when engines above and below 
19 kW share fundamental design features. We request comment on the need 
for, and appropriateness of, such an approach.
5. Special Provisions for Non-Integrated Engine Manufacturers
    We are aware that several Large SI engine manufacturers rely on 
other companies to supply engine blocks or partially assembled engines 
that are then modified for the final application. A similar situation 
occurs for some marine diesel engine manufacturers. To address this for 
the marine engines, we defined these companies as post-manufacture 
marinizers and created a variety of provisions to address their 
particular concerns (64 FR 73300; December 29, 1999).
    The most important concern for these companies is the possibility 
that the company supplying the base engines may discontinue production 
with minimal notice. Once emission standards are in place, this would 
leave the manufacturer with a need to quickly design and certify a 
different engine to meet emission standards. One company has reported 
that two or three months are required to apply closed-loop catalyst 
systems to a new engine. With some additional time to complete the 
certification, a manufacturer in this situation would face a possible 
shutdown in engine assembly until the new engine is ready for 
production. For marine engines, we allow post-manufacture marinizers in 
this situation to request permission to produce uncertified engines for 
up to one year. The post-manufacture marinizer must show that it is not 
at fault and that it would face serious economic hardship without the 
exemption. We request comment on the need for such a provision for 
Large SI engines and on how to limit such a provision to companies that 
rely on partially assembled engines from unrelated companies. If we 
adopt provisions to address this concern, they would likely be similar 
to those adopted for marine diesel engines (see 40 CFR 94.209(b)). We 
also request comment on the potential for the proposed hardship 
provisions to address this concern (see Section VII.C and the proposed 
regulatory language in 40 CFR part 1068, subpart C).

C. Proposed Standards

    In October 1998, California ARB adopted emission standards for 
Large SI engines. We are proposing to extend requirements for these 
engines to the rest of the U.S. in the near term. We are also proposing 
to revise the emission standards and add various provisions in the long 
term, as described below. The near-term and the long-term emission 
standards are based on the use of three-way catalytic converters with 
electronic fueling systems to control emissions, and would differ 
primarily in terms of how well the controls are optimized. In addition 
to the anticipated emission reductions, we project that these 
technologies would provide large savings to operators as a result of 
reduced fuel consumption and other performance improvements.
    An important element of the proposed control program is the 
attempted harmonization with the requirements adopted by California 
ARB. We are aware that inconsistent or conflicting requirements could 
lead to additional costs. Cooperation between agencies has allowed a 
great degree of harmonization, as reflected in this proposed rule. In 
addition to the common structure of the programs, the specific 
provisions that make up the certification requirements and compliance 
programs are consistent with very few exceptions. In most of the cases 
where individual provisions differ, the EPA language is more general 
than that adopted by California, rather than being incompatible. The 
following sections describe the proposed requirements in greater 
detail.
1. What Are the Proposed Standards and Compliance Dates?
    We propose to adopt standards starting in the 2004 model year 
consistent with those adopted by California ARB. These standards, which 
apply to testing only with the applicable steady-state duty cycles, are 
4 g/kW-hr (3 g/hp-hr) for HC+NOX emissions and 50 g/kW-hr 
(37 g/hp-hr) for CO emissions. See Section IV.D for further discussion 
of the steady-state duty cycles. We expect manufacturers to meet these 
standards using three-way catalytic converters and electronically 
controlled fuel systems. These systems would be similar to those used 
for many years in highway applications, but not necessarily with the 
same degree of sophistication.
    Proposing emission standards for these engines starting in 2004 
allows less than the usual lead time for meeting EPA requirements. We 
believe, however, that manufacturers will be able to achieve this by 
expanding their production of the same engines they will be selling in 
California at that time. We have designed our 2004 standards to require 
no additional development, design, or testing beyond what California 
ARB already requires. We request comment on manufacturers' ability to 
produce EPA-compliant engines nationwide in 2004. Any comments should 
address whether there are issues related to production capacity as 
opposed to additional design or testing needs. As proposed, the 
emission standards would allow us to set near-term requirements to 
introduce the low-emission technologies for substantial emission 
reductions with minimal lead time. We request comment on adopting these 
standards for 2004 model year engines.
    Testing has shown that additional time to optimize designs to 
better control emissions will allow manufacturers to meet significantly 
more stringent emission standards that are based on more robust 
measurement procedures. Starting with the 2007 model year, we propose 
to apply emission standards of 3.4 g/kW-hr (2.5 g/hp-hr) for 
HC+NOX emissions and 3.4 g/kW-hr (2.5 g/hp-hr) for CO 
emissions. These standards would apply to emission measurements during 
duty-cycle testing under both steady-state and transient 
operation.\124\ As described in Chapter 4 of the Draft Regulatory 
Support Document, we believe manufacturers can achieve these proposed 
emission standards by optimizing currently available three-

[[Page 51123]]

way catalysts and electronically controlled fuel systems. As described 
in Section IV.D.5, we propose to apply field-testing standards of 4.7 
g/kW-hr (3.5 g/hp-hr) for HC+NOX emissions and 5.0 g/kW-hr 
(3.8 g/hp-hr) for CO emissions for 2007 and later model year engines.
---------------------------------------------------------------------------

    \124\ See Section IV.D for a discussion of duty cycles.
---------------------------------------------------------------------------

    The proposed 2007 standards described above reflect the importance 
of adopting standards that protect human health when regulating engines 
that often operate in enclosed areas, but also include numerous 
applications that operate predominantly outdoors. Emission-control 
technologies for Large SI engines generally pose a tradeoff between 
controlling NOX and CO emissions. Chapter 4 of the 
Regulatory Support Document presents multiple scenarios of emission 
standards with a comparison of calculated ambient NO, NO2, 
and CO levels. We request comment on a combination of emission 
standards that would shift to increase or decrease the emphasis on 
controlling CO emissions. To increase the relative control of CO 
emissions, we would consider emission standards of 4.0 g/kW-hr (3.0 g/
hp-hr) HC+NOX and 2.5 g/kW-hr (1.9 g/hp-hr). To focus more 
on reducing HC+NOX emissions, we would consider emission 
standards of 2.6 g/kW-hr (2.0 g/hp-hr) HC+NOX and 4.4 g/kW-
hr (3.3 g/hp-hr) CO. We have narrowed this range of alternative 
standards to a relatively narrow range to account for the concern for 
individuals who may be exposed to exhaust emissions in enclosed spaces 
or other areas with limited airflow. We request comment on the 
appropriate emission standards for Large SI engines and our analysis of 
CO vs. HC+NOX tradeoffs found in the RIA. We also request 
comment on the potential for manufacturers to take further steps to 
adopt automotive-type technologies that would reduce emissions beyond 
than the levels proposed in this document, either starting in 2007 or 
in a subsequent phase of standards.
    Gasoline-fueled engines, which must generally operate with rich 
air-fuel ratios at heavy loads to avoid premature engine wear from 
overheating components, are further constrained in their ability to 
simultaneously control CO and HC+NOX emissions. Furthermore, 
these engines are more likely to be used outdoors, where there is less 
concern for elevated exposure levels. We are therefore proposing to 
adopt alternate 2007 standards of 1.3 g/kW-hr (1.0 g/hp-hr) for 
HC+NOX emissions and 27 g/kW-hr (20 g/hp-hr) for CO 
emissions. These alternate standards are based on preliminary emission 
measurements with optimized gasoline-fueled engines showing the 
tradeoff of increasing CO emissions at very low NC+NOX 
levels. We are not proposing any restriction on manufacturers' use of 
the alternate standards (for example, for specific fuels or 
applications). Rather, we expect the marketplace to ensure that low-CO 
engines are selected for applications involving significant operation 
in enclosed or partially enclosed areas. We believe this approach will 
maximize HC+NO emission reductions from engines where that is the most 
important emission contribution.
    Except for these alternate standards, the proposed emission 
standards would apply uniformly to all Large SI engines. As described 
in the Draft Regulatory Support Document, based on our current 
information, we do not believe variations among engines significantly 
affect their potential to reduce emissions or their cost of meeting 
emission standards. We request comment on whether it is appropriate to 
differentiate between subclasses of engines to more closely tailor 
emission standards to the capabilities of individual engines or based 
on other relevant criteria, including cost. Also, Large SI engines 
power a wide range of equipment. We request comment on the ability of 
Large SI engines in various applications to incorporate emission-
control technologies and maintain control of emissions over the full 
useful life. We currently have no information indicating that 
application-specific emission standards are appropriate for this class 
of engines, but we request comment on whether there are relevant 
distinctions with respect to different applications. We further request 
comment on whether application-specific standards may be relevant for 
Large SI engines and, if so, what those standards should be. Commenters 
should suggest an appropriate way of addressing any such distinctions 
in the regulations. Finally, we have developed this proposal based on 
the view that it is appropriate to set standards without regard to fuel 
type to prevent incentives for manufacturers to design engines to be 
fueled by fuels subject to less stringent standards. We have proposed 
standards based on this approach, but request comment on whether there 
are advantages to setting separate emission standards for engines 
powered by different fuels, and in particular, on the appropriate 
levels for such standards. A further discussion of the feasibility, 
estimated cost, and emission reductions are in the Draft Regulatory 
Support Document.
    We believe that three years between phases of emission standards 
allows manufacturers enough lead time to meet the more stringent 
emission standards. The projected emission-control technologies for the 
proposed 2004 emission standards should be capable of meeting the 
proposed 2007 emission levels with additional optimization and testing. 
In fact, manufacturers may be able to apply their optimization efforts 
before 2004, leaving only the additional testing demonstration for 
complying with the proposed 2007 standards. The biggest part of the 
optimization effort may be related to gaining assurance that engines 
will meet field-testing emission standards described in Section IV.D.5, 
since engines will not be following a prescribed duty cycle. EPA 
requests comment on the timing of the second phase of emission 
standards. Commenters should address the need to design and certify 
engines, distinguishing between time needed for developing new 
technology, recalibration of existing technology, development of test 
facilities, and the time needed to conduct testing. We also request 
comment on the air quality implications of adjusting the date of the 
long-term standards.
    For gasoline and LPG engines, we are proposing the emission 
standard based on total hydrocarbon measurements, while California ARB 
standards are based on nonmethane hydrocarbons. We believe that 
switching to measurement based on total hydrocarbons should simplify 
testing, especially for field testing of in-use engines with portable 
devices (See Section IV.D.5). To maintain consistency with California 
ARB standards in the near term, we propose to allow manufacturers to 
base their certification through 2006 on either nonmethane or total 
hydrocarbons (see 40 CFR 1048.145 of the proposed regulations). Methane 
emissions from controlled engines operating on gasoline or LPG are 
about 0.1 g/kW&-hr. We request comment on this approach.
    Most of the emission data on which we base the proposed emission 
standards were generated from engines using liquefied petroleum gas 
(LPG). Operation of natural gas engines is very similar to that of LPG 
engines, with one noteworthy exception. Since natural gas consists 
primarily of methane, these engines have a much higher level of methane 
in the exhaust. Methane generally does not contribute to ozone 
formation, so it is often excluded from emission measurements. We 
therefore propose to use nonmethane hydrocarbon emissions for 
comparison with the standard for natural gas engines. While the 
proposed emission standards based on measuring emissions

[[Page 51124]]

in the field depend on total hydrocarbons, this is inconsistent with 
the nonmethane hydrocarbon measurements for certifying natural gas 
engines. We therefore propose to set a NOX-only field-
testing standard for natural gas engines instead of a NOX+HC 
standard. Since control of NOX emissions poses a 
significantly greater challenge for natural gas engines, certification 
testing should provide adequate assurance that these engines have 
sufficiently low nonmethane hydrocarbon emissions. We request comment 
on this proposed arrangement of emission standards and testing 
requirements to account for methane.
2. Could I Average, Bank, or Trade Emission Credits?
    As described in Section III, we often give manufacturers the option 
of showing they meet emission standards using an emission-credit 
program that allows them to introduce a mix of technologies with 
average emission levels below the standards. The emission standards for 
Large SI engines proposed above are based on full compliance by all 
engine families without averaging, banking and trading at 
certification. (Note the separate discussion of averaging, banking, and 
trading that applies to testing in-use engines in Section IV.D.4.) In 
determining whether we should adopt an averaging, banking, and trading 
program in connection with promulgating a standard, we need to consider 
whether the adoption of such a program would affect the determination 
of what emission standards would ``achieve the greatest degree of 
emission reduction achievable through [available technology] . . . 
giving appropriate consideration to the cost of applying such 
technology within the period of time available to manufacturers and to 
noise, energy, and safety factors associated with the application of 
such technology''. The standards we are proposing for Large SI engines 
reflect our assessment of these statutory factors in the absence of an 
ABT program for these engines. If, after notice and comment, we decide 
that an ABT program is appropriate, we will need to reassess the 
appropriate level of these standards considering the statutory factors. 
The emission data described in the Draft Regulatory Support Document 
show that while all engines in this category are likely to be able to 
meet the proposed standard, some engines in this category are likely to 
be capable of operating at a level below the level of the proposed 
emission standards. Incorporating an emission-credit program without 
adjusting the emission standards would allow manufacturers to produce 
some engines that have emissions that are higher than the levels we 
believe are capable of being met by all engines in the category. Given 
the emission data supporting the proposed emission standards, we 
believe that we would therefore need to set more stringent emission 
standards with averaging, banking, and trading provisions to achieve 
the ``greatest degree of emission reduction'' from these engines.
    We request comment on including provisions to average, bank, and 
trade emission credits. We believe the appropriate standards with an 
emission-credit program would be 2.7 g/kW-hr (2.0 g/hp-hr) for 
HC+NOX emissions and 2.7 g/kW-hr (2.0 g/hp-hr) for CO 
emissions. See the Draft Regulatory Support Document for further 
discussion of this issue. Making the comparable adjustments to the 
field-testing measurements described in Section IV.D.5 leads to field-
testing standards under an emission-credit program of 3.8 g/kW-hr (2.8 
g/hp-hr) for HC+NOX emissions and 4.0 g/kW-hr (3.0 g/hp-hr) 
for CO emissions.
    In addition, considering the frequent use of Large SI engines in 
enclosed areas, we may need to cap Family Emission Levels sufficiently 
to address concerns for exposure to elevated concentrations of CO, NO, 
and NO2 emissions. The Draft Regulatory Support Document shows that 
emission levels of 3.4 g/kW-hr for HC+ NOX and for CO appear 
to be appropriate limits related to a scenario of exposure in enclosed 
or other limited-air flow areas. We also believe that there is no type 
of engine or application in the Large SI field that cannot accommodate 
the basic technologies associated with these emission levels, so this 
emission level would serve as an appropriate cap on Family Emission 
Levels in an emission-credit program for both HC+NOX and CO 
emissions. We request comment on these issues.
    For additional, general provisions of an emission-credit program, 
see the proposed regulation language in part 1051, subpart H for 
recreational vehicles. We request comment on all aspects of averaging, 
banking, and trading for Large SI engines. Commenters should address 
appropriate emission levels for the potential mix of technologies under 
consideration. This should include a discussion of any technology or 
market constraints (or incentives) that would lead manufacturers to 
differentiate their engines with varying degrees of emission control. 
In addition, we request comment on the possibility that small-volume 
manufacturers with a limited product offering will be disadvantaged by 
an emission-credit program that may give larger companies a competitive 
advantage in selected markets.
    As an alternative to a program of calculating emission credits for 
averaging, banking, and trading, we are proposing a simpler approach to 
help manufacturers transition to the proposed 2007 emission standards 
(see 40 CFR 1048.145 of the proposed regulations). Under this ``family 
banking'' concept, we would allow manufacturers to certify an engine 
family early. For each year of certifying an engine family early, the 
manufacturer would be able to delay certification of a smaller engine 
family by one year. This would be based on the actual sales of the 
early family and the projected sales volumes of the late family; this 
would require no calculation or accounting of emission credits. The 
manufacturer would verify that actual sales are consistent with 
projected sales at the end of the model year.
3. Is EPA Proposing Blue Sky Standards for These Engines?
    We are proposing a staggered Blue Sky approach aligned with the 
introduction of new emission standards. In the 2003 model year, 
manufacturers could certify their engines to the requirements that 
apply starting in 2004 to qualify for the Blue Sky designation. Since 
manufacturers are producing engines with emission-control technologies 
starting in 2001, these engines would be available to customers outside 
of California desiring emission reductions or fuel-economy 
improvements. We request comment on whether we should make this 
available to 2002 model year engines. Similarly, for 2003 through 2006 
model years, manufacturers could certify their engines to the 
requirements that start to apply in 2007. Finally, we propose to set a 
target of 1.3 g/kW-hr (1.0 g/hp-hr) HC+NOX and 3.4 g/kW-hr 
(2.5 g/hp-hr) CO as a qualifying level for Blue Sky Series engines for 
all model years. The corresponding field-testing standards for Blue Sky 
Series engines would be 1.8 g/kW-hr (1.4 g/hp-hr) HC+NOX and 
5.0 g/kW-hr (3.8 g/hp-hr) CO. We request comment on the level of the 
voluntary standards starting in 2007. We also request comment on the 
advantages of additional labeling provisions that would advertise or 
promote these low-emission products.
4. What Durability Provisions Apply?
    a. Useful life. We propose to set a minimum useful life period of 
seven

[[Page 51125]]

years or until the engine accumulates at least 5,000 operating hours, 
whichever occurs first. This figure, which California ARB also adopted, 
represents an operating period that is common for Large SI engines 
before they undergo rebuild. This also reflects a comparable degree of 
operation relative to the useful life values of 100,000 to 150,000 
miles that apply to automotive engines (assuming an average driving 
speed of 20 to 30 miles per hour).
    Some engines are designed for operation in severe-duty applications 
with a shorter expected lifetime. Concrete saws in particular undergo 
accelerated wear as a result of operating in an environment with high 
concentrations of highly abrasive, airborne concrete dust particles. In 
a previous rulemaking, we adopted a provision for a manufacturer to ask 
us to approve a useful life shorter than the minimum period that would 
otherwise apply. This shortened useful life would be based on 
information from manufacturers showing how long their engines typically 
operated. Extending that provision to Large SI engines would depend on 
a manufacturer including only engines from severe-duty applications in 
a given engine family. The likely practical benefits of segregating 
severe-duty engines would be to shorten the period for establishing 
deterioration factors and to avoid in-use testing on engines that are 
no longer meeting emission standards. We request comment on the 
appropriate approach to useful life values for severe-duty and other 
Large SI engines. We also request comment on any other limitations on 
manufacturers' ability to meet the proposed requirements that may be 
particular to severe-duty engines.
    b. Warranty. We are proposing that manufacturers provide an 
emission-related warranty for at least the first half of an engine's 
useful life (in operating hours) or 3 years, whichever comes first. 
These periods must be longer if the manufacturer offers a longer 
mechanical warranty for the engine or any of its components; this 
includes extended warranties that are available for an extra price. In 
addition, we are proposing the warranty provisions adopted by 
California ARB for high-cost parts. For emission-related components 
whose replacement cost is more than about $400, we are proposing a 
minimum warranty period of at least 70 percent of the engine's useful 
life (in operating hours) or 5 years, whichever comes first. See 
Sec. 1048.120 for a description of which components are emission-
related. We request comment on these proposed warranty provisions.
    c. Maintenance instructions. We are proposing to apply minimum 
maintenance intervals much like those established by California ARB for 
Large SI engines. The minimum intervals define how much maintenance a 
manufacturer may specify to ensure that engines are properly maintained 
for staying within emission standards. We propose to allow 
manufacturers to schedule maintenance on the following components after 
4,500 hours of use: catalysts, fuel injectors, electronic controls and 
sensors, and turbochargers.
    There are two areas of maintenance for which we are especially 
concerned. The first is related to the durability of oxygen sensors. We 
recognize that if an oxygen sensor degrades or fails, emissions can 
increase significantly. It is important to create a strong incentive to 
use the most durable oxygen sensors available. That is why we are 
proposing to apply the 4,500-hour minimum interval to scheduled 
maintenance of oxygen sensors. We are also proposing diagnostic 
requirement to ensure that prematurely failing oxygen sensors are 
detected and replaced on an as-needed basis. If operators would fail to 
replace oxygen sensors after a fault signal, we would not consider that 
engine to be properly maintained. This would invalidate the emission-
related warranty and make the engine ineligible for manufacturer in-use 
testing. We request comment on this approach.
    Our second area of concern is related to the potential need to 
clean LPG fuel mixers. We are aware that for some existing designs, 
fuel mixers can become fouled to the point that they are unable to 
achieve proper control of air-fuel ratios. When this occurs, it can 
usually be remedied by simply removing the mixer and cleaning it. 
Chapter 4 of the Draft Regulatory Support Document describes this in 
further detail, including emission test data showing that fuel systems 
can be quite tolerant of deposits from fuel impurities. We request 
comment on (1) additional test data showing an effect of mixer fouling 
on emissions, (2) whether we should add mixer cleaning as a possible 
scheduled-maintenance item, and (3) how manufacturers could ensure that 
operators of in-use engines would do this cleaning.
    d. Deterioration factors. We are proposing an approach that gives 
manufacturers wide discretion to establish deterioration factors for 
Large SI engines. The general expectation is that manufacturers will 
rely on emission measurements from engines have operated for an 
extended period, either in field service or in the laboratory. The 
manufacturer should do testing as needed to be confident that their 
engines will meet emission standards under the in-use testing program. 
We expect to review deterioration factors to ensure that the projected 
deterioration is consistent with any engine testing under in-use 
testing program. In the first two or three years of certification, we 
would rely on manufacturers' technical judgment (instead of results 
from in-use testing) to appropriately estimate deterioration factors to 
protect themselves from the risk of noncompliance.
    e. In-use fuel quality. Gasoline used in industrial applications is 
generally the same as that used for automotive applications. 
Improvements that have been made to highway-grade gasoline therefore 
carry over directly to nonroad markets. This helps manufacturers be 
sure that fuel quality will not degrade an engine's emission-control 
performance after several years of sustained operation.
    In contrast, there are no enforceable industry or government 
standards for fuel quality for LPG. As a result, LPG composition can 
vary widely. Limited testing data show that this varying fuel quality 
has a relatively small direct effect on emissions from a closed-loop 
engine with a catalyst. The greater concern is that fuel impurities and 
heavy-end hydrocarbons may cause an accumulation of deposits that can 
prevent an emission-control system from functioning properly. While an 
engine's feedback controls can compensate for some restriction in air- 
and fuel-flow, deposits may eventually prevent the engine from 
accurately controlling air-fuel ratios at stoichiometry. In any case, a 
routine cleaning step should remove deposits and restore the engine to 
proper functioning. We are aware of no systematic study of the effect 
of these deposits on in-use emissions, either from highway or from 
nonroad engines.
    We request comment on the following things with respect to the 
quality of in-use LPG:

--The degree to which fuel quality affects emission durability, with 
supporting data.
--The ability of the proposed diagnostic requirements to alert the 
operator to the need for maintenance when the engine is no longer able 
to control air-fuel ratios at stoichiometry.
--The need for manufacturers to specify cleaning of fuel systems as 
part of critical emission-related maintenance, as described above.
--The possibility of applying engine technology to prevent fuel-related 
deposits.

[[Page 51126]]

--The potential to develop an industry-wide specification for in-use 
LPG motor fuels.
--The costs and benefits of fuel additives designed to prevent fuel-
related deposits and how we could ensure that in-use fuels consistently 
include any appropriate additives.
5. Are There Other Requirements for Large SI Engines?
    a. Crankcase emissions. Due to blowby of combustion gases and the 
reciprocating action of the piston, exhaust emissions can accumulate in 
the crankcase. Uncontrolled engine designs route these vapors directly 
to the atmosphere. We have long required that automotive engines 
prevent emissions from the engine's crankcase. Manufacturers generally 
do this by routing crankcase vapors through a valve into the engine's 
air intake system. We propose to require manufacturers to prevent 
crankcase emissions from Large SI engines. Since automotive engine 
blocks are already tooled for closed crankcases, the cost of adding a 
valve for positive-crankcase ventilation is very small. See the Draft 
Regulatory Support Document for further discussion of the costs and 
emission reductions associated with crankcase emissions.
    b. Diagnosing malfunctions. We propose to require that Large SI 
engines diagnose malfunctioning emission-control systems starting with 
the 2007 model year (see Sec. 1048.110). Three-way catalyst systems 
with closed-loop fueling control work well only when the air-fuel 
ratios are controlled to stay within a narrow range around 
stoichiometry.\125\ Worn or broken components or drifting calibrations 
over time can prevent an engine from operating within the specified 
range. This increases emissions and can significantly increase fuel 
consumption and engine wear. The operator may or may not notice the 
change in the way the engine operates.
---------------------------------------------------------------------------

    \125\ Stoichimetry is the proportion of a mixture of air and 
fuel such that the fuel is fully oxidized with no remaining oxygen. 
For example, stoichiometric combustion in gasoline engines typically 
occurs at an air-fuel mass ratio of about 14.7.
---------------------------------------------------------------------------

    The proposed diagnostic requirement focuses solely on maintaining 
stoichiometric control of air-fuel ratios. This kind of design would 
detect problems such as broken oxygen sensors, leaking exhaust pipes, 
fuel deposits, and other things that would require maintenance to keep 
the engine at the proper air-fuel ratio.
    Some companies are already producing engines with diagnostic 
systems that check for consistent air-fuel ratios. Their initiative 
supports the idea that diagnostic monitoring provides a mechanism to 
help keep engines tuned to operate properly, with benefits for both 
controlling emissions and maintaining optimal performance. There are 
currently no inspection and maintenance programs for nonroad engines, 
so the most important variable in making the emission control and 
diagnostic systems effective is in getting operators to repair the 
engine when the diagnostic light comes on. This calls for a relatively 
simple design to avoid false failures as much as possible. The proposed 
diagnostic requirements therefore focus on detecting inappropriate air-
fuel ratios, which is the most likely failure mode for three-way 
catalyst systems. We propose to specify that the malfunction-indicator 
light should go on when an engine operates for a full minute without 
reaching a stoichiometric air-fuel ratio. If this specified time is too 
long, we could be allowing extended open-loop operation with increased 
emission levels. We request comment on whether this approach is 
appropriate and whether this one-minute period should be longer or 
shorter to provide timely detection without causing false failures. In 
addition, we request comment on the appropriateness of other 
malfunction indicators, such as a measuring the frequency of crossing 
stoichiometry or monitoring the voltage range of oxygen sensors.
    Some natural gas engines may meet standards with lean-burn designs 
that never approach stoichiometric combustion. While manufacturers may 
design these engines to operate at specific air-fuel ratios, catalyst 
conversion is not as sensitive to air-fuel ratio as with stoichiometric 
designs. We request comment on whether these engines should show a 
malfunction condition when departing from a targeted air-fuel ratio, or 
whether some other parameters would more appropriately detect for any 
possible failure modes.
    For cars and light-duty trucks, our diagnostic system requirements 
call for monitoring of misfire and reduction in catalyst conversion 
efficiency. We are not proposing these additional diagnostic features 
for nonroad Large SI engines. Requiring misfire and catalyst conversion 
monitoring, which are more difficult to detect, would require extensive 
development effort to define appropriate failure thresholds and for 
manufacturers to design systems to avoid false failures and false 
positive detection. In the context of this rulemaking, which proposes 
initial standards for nonroad Large SI engines, we believe it is 
important for manufacturers to design engines for low emissions before 
taking the step of designing a thorough, complex diagnostic system. We 
believe that monitoring air-fuel ratio will achieve the majority of the 
benefit available from diagnostic systems at a reasonable cost. 
Moreover, without a corresponding inspection-and -maintenance program, 
operators are most likely to respond to diagnostic warnings with a 
system that is clear and simple.
    An example illustrates a typical scenario. One forklift operator 
driving an LPG-powered lift truck with three-way catalyst and closed-
loop electronic controls noticed that he was able to run two hours 
shorter than usual on a standard tank of fuel. Since power 
characteristics were not noticeably affected, the operator had done no 
maintenance or investigation to correct the problem. Simply replacing 
the defective oxygen sensor restored the engine to its original level 
of performance (for fuel consumption and emission control). A 
diagnostic light would serve to alert operators that the engine needs 
attention and would provide help in identifying any specific parts 
causing the problem. Since the basic function of a three-way catalyst 
system is generally consistent with power and fuel-economy 
considerations, operators would have good reason to respond to a 
diagnostic light.
    The automotive industry has developed a standardized protocol for 
diagnostic systems, including hardware specifications, and uniform 
trouble codes. Some of these will apply to nonroad engines, but some 
will not. In the proposed regulations we reference standards adopted by 
the International Organization for Standardization (ISO) for automotive 
systems. If these standards do not apply to the simpler diagnostic 
design proposed for Large SI engines, we encourage engine manufacturers 
to cooperate with each other and with other interested companies to 
develop new standards specific to nonroad engines.
    As described in the proposed regulatory text, the malfunction light 
should go on when the system detects a malfunction and must stay on 
until the engine is serviced or until the engine returns to consistent, 
normal operation. Stored diagnostic trouble codes would identify as 
closely as possible the cause of the malfunction, which could then be 
read by any qualified technician.
    We request comment on these proposed diagnostic system 
requirements.

[[Page 51127]]

    c. Evaporative emissions. Evaporative emissions occur when fuel 
evaporates and is vented into the atmosphere. They can occur while an 
engine or vehicle is operating and even while it is not being operated. 
Among the factors that affect evaporative emissions are:
     Fuel metering (fuel injectors or carburetor).
     The degree to which fuel permeates fuel lines and fuel 
tanks.
     Proximity of the fuel tank to the exhaust system or other 
heat sources.
     Whether the fuel system is sealed and the pressure at 
which fuel vapors are ventilated.
    In addition, some gasoline fuel tanks may be exposed to heat from 
the engine compartment and high-temperature surfaces such as the 
exhaust pipe. In extreme cases, fuel can start boiling, producing very 
large amounts of gasoline vapors vented directly to the atmosphere.
    Evaporative emissions from Large SI engines and the associated 
equipment represent a significant part of their overall hydrocarbon 
emissions. The magnitude of evaporative emissions varies widely 
depending on the engine design and application. LPG-fueled equipment 
generally has very low evaporative emissions because of the tightly 
sealed fuel system. At the other extreme, carbureted gasoline-fueled 
equipment can have high rates of evaporation. Southwest Research 
Institute measured emissions from several gasoline-fueled Large SI 
engines and found them to vary from about 12 g/day up to almost 100 g/
day.\126\ This study did not take into account the possibility of 
unusually high fuel temperatures during engine operation, as described 
further below.
---------------------------------------------------------------------------

    \126\ ``Measurement of Evaporative Emissions from Off-Road 
Equipment,'' by James N. Carroll and Jeff J. White, Southwest 
Research Institute (SwRI 08-1076), November 1998, Docket A-2000-01, 
document II-A-10.
---------------------------------------------------------------------------

    We are proposing to require basic measures to reduce evaporative 
emissions from gasoline-fueled Large SI engines. The usual approach to 
regulating emissions from nonroad and other mobile engines is to define 
a measurement procedure and adopt numerical limit values (or standards) 
that together determine a minimum required level of performance. 
Manufacturers are then free to use any kind of technology to meet these 
performance standards.
    Since the Act directs us to first consider regulating nonroad 
engines with standards similar to those that apply to motor vehicles, 
we must consider test-based evaporative emission standards that would 
be comparable to those for automobiles. However, we have practical 
concerns with requiring that approach as the only option for 
manufacturers. These concerns relate primarily to the nonintegrated 
nature of these industries and the wide variety of applications in 
which the engines are used. Some manufacturers could face difficulties 
certifying to specific numerical emission levels because of the large 
variation in fuel system components needed to fit the many varied kinds 
of equipment. While a test-based standard may be feasible, we believe 
we should allow the use of other cost-effective approaches that could 
be more appropriate for this industry.
    We propose to adopt an evaporative emission standard of 0.2 grams 
per gallon of fuel tank capacity for heating a fuel tank from 72 deg. 
to 96 deg. F. We further propose that manufacturers can rely on a 
design-based certification instead of measuring emissions by adopting 
one of the designs described in this paragraph. We have identified four 
technologies that would adequately prevent evaporative emissions to 
show compliance with the proposed evaporative emission standard. First, 
pressurized fuel tanks control evaporative emissions by suppressing 
vapor generation. In its standards for industrial trucks operating in 
certain environments, Underwriters Laboratories requires that trucks 
use self-closing fuel caps with tanks that stay sealed to prevent 
evaporative losses; venting is allowed for positive pressures above psi 
or for vacuum pressures of at least 1.5 psi.\127\ Any Large SI engines 
or vehicles operating with these pressures would satisfy the 
certification requirements. Second, for applications where such high 
fuel tank pressures are undesirable, manufacturers could instead rely 
on an air bladder inside the fuel tank that changes in volume to keep 
the system in equilibrium at atmospheric pressure.\128\ Third, an 
automotive-type system that stores fuel tank vapors for burning in the 
engine would be another alternative technology. Finally, collapsible 
bladder tanks, which change in volume to prevent generation of a vapor 
space or vapor emissions, are also commercially available. Also, 
similar to the Underwriters Laboratories' requirement, we are proposing 
that manufacturers must use self-closing or tethered fuel caps to 
ensure that fuel tanks designed to hold pressure are not inadvertently 
left exposed to the atmosphere. Section 1048.105 of the proposed 
regulations describes these design specifications in greater detail. We 
request comment on these approaches and on whether we should consider 
tank insulation as an alternative or complementary strategy for meeting 
the proposed requirements on a design basis.
---------------------------------------------------------------------------

    \127\ ``Industrial Trucks, Internal Combustion Engine-Powered,'' 
UL558, ninth edition, June 28, 1996, paragraphs 26.1 through 26.4, 
Docket A-2000-01, document II-A-28. See Section XI.E for our 
consideration of incorporating the UL requirements into our 
regulations by reference.
    \128\ ``New Evaporative Control System for Gasoline Tanks,'' EPA 
Memorandum from Charles Moulis to Glenn Passavant, March 1, 2001, 
Docket A-2000-01, document II-B-16.
---------------------------------------------------------------------------

    In addition, we propose to require that engine manufacturers use 
(or specify that equipment manufacturers installing their engines use) 
fuel lines meeting the industry performance standard for permeation-
resistant fuel lines developed for motor vehicles.\129\ While metal 
fuel lines do not have problems with permeation, manufacturers should 
use discretion in selecting materials for grommets and valves 
connecting metal components to avoid high-permeation materials. 
Evaporative emission standards for motor vehicles have led to the 
development of a wide variety of permeation-resistant polymer 
components.
---------------------------------------------------------------------------

    \129\ SAE J2260 ``Nonmetallic Fuel System Tubing with One or 
More Layers,'' November 1996.
---------------------------------------------------------------------------

    Finally, manufacturers can take steps to reduce fuel temperatures 
during operation. The use of fuel injection and the associated 
recirculating fuel lines and in-tank fuel pumps may even increase the 
heat load into the fuel tank, which would tend to increase emission 
rates generally and may increase the occurrence of fuel boiling. The 
Underwriters Laboratories specification for forklifts attempts to 
address this concern through a specified maximum fuel temperature, but 
the current limit does not prevent fuel boiling.\130\ We are proposing 
a standard that prohibits fuel boiling during continuous operation at 
30 deg. C (86 deg. F). Engine manufacturers would have to incorporate 
designs that reduce the heat load to the fuel tank to prevent boiling. 
For companies that sell loose engines, this may involve instructions to 
equipment manufacturers to help ensure, for example, that fuel tank 
surfaces are exposed to ambient air rather than to exhaust pipes or 
direct engine heat. Engine manufacturers may specify a maximum fuel 
temperature for the final installation. Such a temperature limit should 
be well below 53 deg. C (128 deg. F), the

[[Page 51128]]

temperature at which summer-grade gasoline (9 RVP) typically starts 
boiling.
---------------------------------------------------------------------------

    \130\ UL558, paragraph 19.1.1, Docket A-2000-01, document II-A-
28.
---------------------------------------------------------------------------

    An additional source of evaporative emissions is from carburetors. 
Carburetors often have high hot soak emissions (immediately after 
engine shutdown). We expect manufacturers to convert carbureted designs 
to fuel injection as a result of the proposed exhaust emission 
standards. While we are not proposing to mandate this technology, we 
believe the need to reduce exhaust emissions will cause engine 
manufacturers to use fuel injection on all gasoline engines. This 
change alone would eliminate most hot soak emissions. We request 
comment on whether the procedure described in the previous paragraphs 
would require fuel injection. In addition, we request comment on the 
possibility of meeting the 2007 exhaust emission standards with 
carbureted engines.
    Engine manufacturers using design-based certification would need to 
describe in the application for certification the selected design 
measures and specifications to address evaporative losses from 
gasoline-fueled engines. For loose-engine sales, this would include 
emission-related installation instructions that the engine manufacturer 
would give to equipment manufacturers.
    With the ready availability of automotive technology and the 
development effort already in place to meet Underwriters Laboratories' 
requirements, we believe the proposed evaporative-control provisions 
would not pose a major development burden in most cases. We expect 
manufacturers generally to meet the proposed evaporative requirements 
with low-cost, off-the-shelf technologies. Individual engines may need 
somewhat more development effort to ensure compliance, but the hardware 
and testing costs would be minimal. We estimate an average cost of 
about $10 per engine for those engines that would be subject to 
evaporative-emission standards. Once this program is fully phased in, 
we estimate over 7,500 tons of HC reductions annually. See the Draft 
Regulatory Support Document for further information about the estimated 
costs and benefits of evaporative emission controls.
    Reducing evaporative losses would not only provide health and 
safety advantages, but would contribute to overall fuel savings from 
Large SI engines. We request comment on the proposed measures to 
control evaporative emissions, including the potential cost and 
effectiveness of (1) an evaporative emission standard at 0.2 g/gal of 
fuel, (2) the optional design standards, and (3) the proposed fuel-line 
and fuel-temperature requirements. We also request comment on any 
additional or complementary approaches.

D. Proposed Testing Requirements and Supplemental Emission Standards

1. What Duty Cycles Would Be Used To Measure Emissions?
    For 2004 through 2006 model years, we are proposing to use the same 
steady-state duty cycles adopted by California ARB. For most engines 
this involves the testing based on the ISO C2 duty cycle, with a 
separate duty cycle for constant-speed applications based on the ISO D2 
duty cycle. These duty cycles are described further below.
    Starting in 2007, we are proposing an expanded set of duty cycles, 
again with separate treatment for variable-speed and constant-speed 
applications. These duty-cycles are each comprised of three segments: 
(1) A warm-up segment, (2) a transient segment, and (3) a steady-state 
segment. Each of these segments, described briefly in this section, 
include specifications for the speed and load of the engine as a 
function of time. Measured emissions during the transient and steady-
state segments must meet the emission standards that apply. In general, 
the proposed duty-cycles are intended to include representative 
operation from the wide variety of in-use applications. This includes 
highly transient low-speed forklift operation, constant-speed operation 
of portable equipment, and intermediate-speed vehicle operation. 
Chapter 4 of the Draft Regulatory Support Document describes the duty 
cycles in greater detail. We request comment on the proposed duty 
cycles.
    Ambient temperatures in the laboratory must be between 20 deg. and 
30 deg. C (68 and 86 deg. F) during duty-cycle testing. This improves 
the repeatability of emission measurements when the engine runs through 
its prescribed operation. We nevertheless expect manufacturers to 
design for controlling emissions under broader ambient conditions, as 
described in Section IV.D.5.
    The warm-up segment begins with a cold-start. This means that the 
engine should be very near room temperature before the test cycle 
begins. Once the engine is started, it would be operated over the first 
3 minutes of the specified transient duty cycle without emission 
measurement. The engine then idles for 30 seconds before starting the 
prescribed transient cycle. The purpose of the warm-up segment is to 
bring the engine up to normal operating temperature in a standardized 
way. The 3-minute warm-up period allows enough time for engine-out 
emissions to stabilize, for the catalyst to warm up enough to become 
active, and for the engine to start closed-loop operation. This serves 
as a defined and achievable target for the design engineer to limit 
cold-start emissions to a relatively short period.
    The transient segment of the general duty cycle is a composite of 
forklift and welder operation. This duty cycle was developed by 
selecting segments of measured engine operation from two forklifts and 
a welder as they performed their normal functions. This transient 
segment captures the wide variety of operation from a large majority of 
Large SI engines. Emissions measured during this segment are averaged 
over the entire transient segment to give a single value in g/kW.
    Steady-state testing consists of engine operation for an extended 
period at several discrete speed-load combinations. Associated with 
these test points are weighting factors that allow a single weighted-
average steady-state emission level in g/kW. The principal duty cycle 
is based on the ISO C2 cycle, which has five modes at various 
intermediate speed points, plus one mode at rated speed and one idle 
mode. The combined intermediate-speed points at 10, 25, and 50 percent 
account for over 70 percent of the total modal weighting. While any 
steady-state duty cycle is limited in how much it can represent 
operation of engines that undergo transient operation, the distribution 
of the C2 modes and their weighting values aligns significantly with 
expected and measured engine operation from Large SI engines. In 
particular, these engines are generally not designed to operate for 
extended periods at high-load, rated speed conditions. Field 
measurement of engine operation shows, however, that forklifts operate 
extensively at lower speeds than those included in the C2 duty cycle. 
While we believe the test points of the C2 duty cycle are 
representative of engine operation from many applications of Large SI 
engines, supplementing the steady-state testing with a transient duty 
cycle is necessary to adequately include engine operation 
characteristic of what occurs in the field.
    Engines such as generators, welders, compressors, and pumps are 
governed to operate only at a single speed with varying loads. We are 
proposing a combination of transient and steady-state testing that 
applies specifically to constant-speed engines. The transient duty-
cycle segment includes 20 minutes of engine operation based on measured

[[Page 51129]]

welder operation. We expect to propose this same transient duty cycle 
for constant-speed nonroad diesel engines. Manufacturers would also 
test constant-speed Large SI engines with steady-state operation based 
on the ISO D2 duty cycle, which specifies engine operation at rated 
speed with five different load points. This same steady-state duty 
cycle applies to constant-speed, nonroad diesel engines. Emission 
values measured on the D2 duty cycle are treated the same as values 
from the C2 duty cycle; the same numerical standards apply to both 
cycles. Manufacturers selling engines for both constant-speed and 
variable-speed applications would omit the constant-speed transient 
test, since that operation is included in the general transient test.
    We are concerned that engines certified with the C2 duty cycle may 
be installed in constant-speed applications; or, similarly that engines 
certified with the D2 duty cycle may be installed in variable-speed 
applications. Since the C2 cycle includes very little operation at 
rated speed, it is not effective in ensuring control of emissions for 
constant-speed engines. The D2 cycle is even less capable of predicting 
emission performance from variable-speed engines. To address this, we 
are proposing that manufacturers routinely test engines on both the C2 
and D2 duty cycles.\131\ Manufacturers selling only a variable-speed or 
only constant-speed engines in an engine family would be allowed to 
omit testing with the duty cycle that would not apply. With a more 
limited certification, however, we would require the manufacturer to 
add information to the engine label and any emission-related 
installation instructions to clarify that the engine has a limited 
certification. We request comment on this approach to variable- and 
constant-speed engines.
---------------------------------------------------------------------------

    \131\ It would not be necessary to repeat the warm-up and 
transisent segments for additional steady-state duty cycles.
---------------------------------------------------------------------------

    Some diesel-derived engines operating on natural gas with power 
ratings up to 1,500 or 2,000 kW may be covered by the proposed emission 
standards. Engine dynamometers with transient-control capabilities are 
generally limited to testing engines up to 500 or 600 kW. We propose at 
this time to waive emission standards and testing requirements related 
to transient duty cycles for engines above 560 kW. We would likely 
review this provision for Large SI engines once we have reached a 
conclusion on the same issue for nonroad diesel engines. We would 
expect to treat both types of engines the same way. Note that the 
field-testing emission standards still apply to engines that don't 
certify to transient duty-cycle standards.
2. What Fuels Would Be Used During Emission Testing?
    For gasoline-fueled Large SI engines, we are proposing to use the 
same specifications we have adopted for testing gasoline-fueled highway 
vehicles and engines. This includes the revised specification to cap 
sulfur levels at 80 ppm (65 FR 6698, February 10, 2000).
    For LPG and natural gas, we are proposing to use the same 
specifications adopted by California ARB. We understand that in-use 
fuel quality for LPG and natural gas varies significantly in different 
parts of the country and at different times of the year. Not all in-use 
fuels outside California meet California ARB specifications for 
certification fuel, but fuels meeting the California specifications are 
nevertheless widely available. Test data show that LPG fuels with a 
much lower propane content have only slightly higher NOX and 
CO emissions (see Chapter 4 of the Draft Regulatory Support Document 
for additional information). These data support our belief that engines 
certified using the specified fuel will achieve the desired emission 
reduction for a wide range of in-use fuels.
    Unlike California ARB, we propose to apply the fuel specifications 
to testing only for emission measurements, not to service accumulation. 
We propose to allow service accumulation between emission tests with 
certification fuel or any commercially available fuel of the 
appropriate type. We would similarly allow manufacturers to choose 
between certification fuel and any commercial fuel for in-use 
measurements to show compliance with field-testing emission standards.
    We request comment on appropriate fuel specifications for all types 
of engine testing.
3. Are There Proposed Production-Line Testing Provisions for Large SI 
Engines?
    The provisions described in Section III.C.4 apply to Large SI 
engines. These proposed requirements are consistent with those adopted 
by California ARB. One new issue specific to Large SI engines relates 
to the duty cycles for measuring emissions from production-line 
engines.
    For routine production-line testing, we propose to require emission 
measurements only with the steady-state duty cycles used for 
certification. Due to the cost of sampling equipment for transient 
engine operation, we are not proposing to require routine transient 
testing of production-line engines. We believe that steady-state 
emission measurements will give a good indication of manufacturers' 
ability to build engines consistent with the prototypes on which their 
certification data are based. We also propose, however, to reserve the 
right to direct a manufacturer to measure emissions with a transient 
duty cycle if we believe it is appropriate. One indication of the need 
for this transient testing would be if steady-state emission levels 
from production-line engines are significantly higher than the emission 
levels reported in the application for certification for that engine 
family. For manufacturers with the capability of measuring transient 
emission levels at the production line, we would recommend doing 
transient tests to better ensure that in-use tests will not reveal 
problems in controlling emissions during transient operation. 
Manufacturers would not need to make any measurements to show that 
production-line engines can meet field-testing emission standards.
    We request comment on all aspects of the proposed production-line 
testing requirements, including engine sampling rates and options for 
using alternative testing methods.
4. Are There Proposed In-Use Testing Provisions for Large SI Engines?
    While the certification and production-line compliance requirements 
are important to ensure that engines are designed and produced in 
compliance with established emission limits, there is also a need to 
confirm that manufacturers build engines with sufficient durability to 
meet emission limits as they age in service. Consistent with the 
California ARB program, we are proposing to require engine 
manufacturers to conduct emission tests on a small number of field-aged 
engines to show they meet emission standards.
    Under the proposed program, we may generally select up to 25 
percent of a manufacturer's engine families in a given year to be 
subject to in-use testing (see Table IV.D-1). Most companies would need 
to test at most one engine family per year. Manufacturers may conduct 
in-use testing on any number of additional engine families at their 
discretion. We request comment on this maximum rate of testing engines 
under the proposed in-use testing program.

[[Page 51130]]

               Table IV.D-1.--Maximum In-Use Testing Rate
------------------------------------------------------------------------
                                                               Maximum
                                                              number of
                                                               families
        Number of engine families for a manufacturer          subject to
                                                                in-use
                                                               testing
                                                              each year
------------------------------------------------------------------------
1..........................................................            1
2..........................................................            1
3..........................................................            1
4..........................................................            1
5..........................................................            1
6..........................................................            1
7..........................................................            1
8..........................................................            2
9..........................................................            2
10.........................................................            2
11.........................................................            2
12.........................................................            3
------------------------------------------------------------------------

    We are also proposing that manufacturers in unusual circumstances 
have the ability to develop an alternate plan to fulfill any in-use 
testing obligations, consistent with a similar program we have adopted 
for outboard and personal watercraft marine engines. These 
circumstances include total sales for an engine family below 200 per 
year, installation only in applications where testing is not possible 
without irreparable damage to the vehicle or engine, or any other 
unique feature that prevents full emission measurements. We request 
comment on these provisions.
    While this flexibility for alternate measurements would be 
available to small-volume manufacturers, we also request comment on 
applying in-use testing requirements to very small-volume engine 
families in general. While the proposed regulations would allow us to 
select an engine family every year from an engine manufacturer, there 
are several reasons why small volume manufacturers could expect a less 
demanding approach. These manufacturers may have only one or two engine 
families. If a manufacturer shows that an engine family meets emission 
standards in an in-use testing exercise, that could provide adequate 
data to show compliance for that engine family for a number of years, 
provided the manufacturer continues to produce those engines without 
significantly redesigning them in a way that could affect their in-use 
emissions performance and that we do not have other reason to suspect 
noncompliance. Also, where we had comfort that a manufacturer's engines 
were likely in good in-use compliance, we would generally take the 
approach of selecting engine families based on some degree of 
proportionality. To the extent that manufacturers produce a smaller 
than average proportion of engines, they could expect that we would 
select their engine families less frequently, especially if other 
available data pointed toward clear in-use compliance.
    We are also proposing that manufacturers in unusual circumstances 
have the ability to develop an alternate plan to fulfill any in-use 
testing obligations. These include total sales for an engine family 
below 200 per year, installation only in applications where testing is 
not possible without irreparable damage, or any other unique feature 
that prevents full emission measurements. We request comment on these 
provisions. While this flexibility would be available to small-volume 
manufacturers, we also request comment on applying in-use testing 
requirements to these companies in general. While the proposed 
regulations would allow us select an engine family every year from an 
engine manufacturer, there are reasons why these companies could expect 
a less demanding approach. First, to avoid unfair treatment of 
individual manufacturers, we would generally take the approach of 
selecting engine families based on some degree of proportionality. To 
the extent that manufacturers produce a smaller than average proportion 
of engines, they could expect that we would select their engine 
families less frequently. In addition, our experience in implementing a 
comparable testing program for recreational marine engines provides a 
history of how we implement in-use testing requirements.
    Engines can be tested one of two ways. First, manufacturers can 
remove engines from vehicles or equipment and test the engines on a 
laboratory dynamometer using certification procedures. For 2004 through 
2006 model year engines, this would be the same steady-state duty cycle 
used for certification; manufacturers may optionally test engines on 
the dynamometer under transient operating conditions. For 2007 and 
later model year engines, manufacturers must test engines using both 
steady-state and transient duty cycles, as in certification.
    Second, manufacturers may use the proposed equipment and procedures 
for testing engines without removing them from the equipment (referred 
to in this document as field-testing). See Section IV.D.5 for a more 
detailed description of how to measure emissions from engines during 
normal operation in the field. Since engines operating in the field 
cannot be controlled to operate on a specific duty cycle, compliance 
would be demonstrated by comparing the measured emission levels to the 
proposed field-testing emission standards, which would have higher 
numerical value to account for the possible effects of different engine 
operation. Because the engine operation can be so variable, however, 
engines tested to show compliance only with the field-testing emission 
standards would not be eligible to participate in the in-use averaging, 
banking, and trading program (described below).
    We could give directions to include specific types of normal 
operation to confirm that engines are controlling emissions in real 
operation. For example, for testing to show compliance with field-
testing emission standards, we may identify specific types of operation 
on specific days or times to sample emissions, as long as these fall 
within the range of normal operation for the application. Dynamometer 
testing might include operation over a torque-speed trace measured from 
any appropriate equipment. If we don't provide specific direction, 
manufacturers would use their discretion to show that engines comply 
with the field-testing standards, much like for certification (see 
Section IV.D.5).
    Along with the in-use testing program, we are proposing an in-use 
credit program designed to reduce compliance cost without reducing 
environmental benefits. The program would provide manufacturers with 
flexibility in addressing potential in-use noncompliance in a way that 
we agree would avoid the need for a determination of nonconformity 
under Clean Air Act section 207(c), and thereby avoid a recall. 
Participation in this program would be voluntary.
    The flexibility of the proposed in-use credit program is 
appropriate given the particular circumstances of the Large SI engine 
industry. For an engine family failing in-use testing, we believe 
recalling the nonconforming engines may be particularly burdensome and 
impractical for this industry, mainly due to the difficulty of tracking 
the nonconforming engines. Recalling the engines would therefore 
require substantial resources, yet may not be highly effective in 
remedying the excess emissions.
    Clean Air Act section 213 requires engines to comply with emission 
standards throughout their regulatory useful lives, and section 207 
requires a manufacturer to remedy in-use nonconformity when we 
determine that a substantial number of properly maintained and used 
engines fail to conform with the applicable emission standards (42 
U.S.C. 7541). Once we make this determination, recall would be 
necessary to remedy the

[[Page 51131]]

nonconformity. However, under these circumstances, where it is expected 
that recall would be impractical and largely ineffective, it is 
appropriate not to make a determination of substantial nonconformity 
where a manufacturer uses emission credits to offset in-use 
noncompliance. Thus, under the Clean Air Act, we may choose to make no 
section 207(c) determination of substantial nonconformity where an 
engine manufacturer uses emission credits to offset any noncompliance 
with the statute's in-use performance requirements. Though the language 
of section 213(d) is silent on the issue of emission credits, it 
generally allows considerable discretion in determining what 
modifications to the highway regulatory scheme are appropriate for 
nonroad engines.
    In-use credits would be based on in-use testing conducted by the 
manufacturer. For a given engine family, the in-use compliance level 
would be determined by averaging the results from in-use testing 
performed for that engine family. If the in-use compliance level is 
below the applicable standard, the manufacturer would generate in-use 
credits for that engine family. If the in-use compliance level is above 
the standard, the engine family would experience a credit deficit. 
Manufacturers calculate credits based on the measured emission levels 
(when compared with applicable emission standards) and several 
additional variables, such as rated power, useful life, and engine 
family population. To ensure that emission credits show a real degree 
of emission control relative to the emission standard, we are proposing 
that emission credits must be based on transient duty-cycle operation 
on a dynamometer. An exception would apply for averaging emission 
levels from 2004 through 2006 model year engines, where we would allow 
for emission credits based on steady-state emission testing.
    While we are proposing the in-use credit program adopted by 
California ARB, an additional concern relates to the status of emission 
credits over the long term. This would be our first step in setting 
emission standards for this category of engines, which increases the 
uncertainty of setting standards requiring the ``greatest degree of 
emission reduction achievable,'' as called for in the Clean Air Act. If 
manufacturers are able to use the projected technologies to 
consistently achieve emission levels even lower than we require, in-use 
testing over several years can lead to a large pool of in-use emission 
credits. To avoid making the in-use testing program meaningless for 
some engines, especially in the context of a transition to a next tier 
of emission standards , we would not intend to use credits older than 
three model years in deciding whether to take administrative action 
under section 207(c). This should address the concern for accumulating 
credits without taking away EPA and the manufacturers' substantial 
flexibility to use credits to offset marginally noncompliant engines.
    We request comment on all aspects of the proposed in-use testing 
requirements.
5. What About Field-Testing Emission Standards and Test Procedures?
    To enable field-testing of Large SI engines and to address concerns 
for controlling emissions outside of the specific duty cycles proposed 
to measure emissions for certification, we are proposing procedures and 
standards that apply to a wider range of normal engine operation.
    a. What is the field-testing concept? Measuring emissions from 
engines in the field as they undergo normal operation while installed 
in nonroad equipment addresses two broad concerns. First, this provides 
a low-cost method of testing in-use engines. Second, testing has shown 
that emissions can vary dramatically under certain modes of operation. 
Field-testing addresses this by including emission measurements over 
the broad range of normal engine operation. This may include varying 
engine speeds and loads according to real operation and may include a 
reasonable range of ambient conditions, as described below.
    No engine operating in the field can follow a prescribed duty cycle 
for a consistent measure of emission levels. Similarly, no single test 
procedure can cover all real-world applications, operations, or 
conditions. Specifying parameters for testing engines in the field and 
adopting an associated emission standard provides manufacturers with a 
framework for showing that their engines will control emissions under 
the whole range of normal operation in the relevant nonroad equipment.
    To ensure that emissions are controlled from Large SI engines over 
the full range of speed and load combinations seen in the field, we are 
proposing supplemental emission standards that apply more broadly than 
the duty-cycle standard. These standards would apply to all regulated 
pollutants (NOX, HC, and CO) under all normal operation 
(steady-state or transient). We propose to exclude abnormal operation 
(such as very low average power and extended idling time), but not 
restrict operation to any specific combination of speeds and loads. In 
addition, we are proposing that the field-testing standards would apply 
under a broad range of in-use ambient conditions, both to ensure robust 
emission controls and to avoid overly restricting the times available 
for testing. These provisions are described in detail below.
    b. What are the field-testing emission standards? Starting with the 
2007 model year, we propose to apply field-testing emission standards 
of 4.7 g/kW-hr (3.5 g/hp-hr) for HC+NOX emissions and 6.7 g/
kW-hr (5.0 g/hp-hr) for CO emissions. As described above for the duty-
cycle standards, we believe manufacturers will be able to use the 
additional time beyond 2004 to optimize their designs to control 
emissions under the full range of normal in-use operation. As described 
in Chapter 4 of the Draft Regulatory Support Document, we believe 
manufacturers can achieve these proposed emission standards using 
currently available three-way catalysts and electronically controlled 
fuel systems.
    As described above, we are proposing alternate emission standards 
for those engines operating predominantly outdoors. The corresponding 
proposed field-testing standards are 1.8 g/kW-hr (1.3 g/hp-hr) for 
HC+NOX emissions and 41 g/kW-hr (31 g/hp-hr) for CO 
emissions.
    Manufacturers have expressed an interest in using field-testing 
procedures before the 2007 model year to show that they can meet 
emission standards as part of the in-use testing program. While we are 
not proposing specific field-testing standards for 2004 through 2006 
model year engines, we are proposing to allow this as an option. In 
this case, manufacturers would conduct the field testing as described 
here to show that their engines meet the 4 g/kW-hr HC+ NOX 
standard and the 50 g/kW-hr CO standard. This could give manufacturers 
the opportunity to do testing at significantly lower cost compared with 
laboratory testing. Preliminary certification data from California ARB 
show that manufacturers are reaching steady-state emission levels well 
below emission standards, so we would expect any additional variability 
in field-testing measurements not to affect manufacturers' ability to 
meet the same emission standards. We request comment on the need for 
and appropriateness of this provision. We also request comment on 
whether there should be a separate field-testing standard, higher or 
lower than the proposed duty-cycle standards, to provide adequate 
assurance that the

[[Page 51132]]

engines operate with the required level of emission control.
    These proposed field-testing standards are based on emission data 
measured with the same emission-control technology used to establish 
the duty-cycle standards. The higher numerical standard for field 
testing reflects the observed variation in emissions for varying engine 
operation, the projected effects of ambient conditions on the projected 
technology, and the accuracy limitations of in-use testing equipment 
and procedures. Conceptually, we believe that field-testing standards 
should primarily require manufacturers to adjust engine calibrations to 
effectively manage air-fuel ratios under varying conditions. The 
estimated cost of complying with emission standards includes an 
allowance for the time and resources needed for this recalibration 
effort (see Section IX.B. for total estimated costs per engine).
    EPA generally requires manufacturers to show at certification that 
they are capable of meeting requirements that apply for any in-use 
testing. This adds a measure of assurance to both EPA and manufacturers 
that the engine design is sufficient for any in-use engines to pass any 
later testing. For Large SI engines, we are proposing that 
manufacturers show in their application for certification that they 
meet the field-testing standards. Manufacturers would submit a 
statement that their engines will comply with field-testing emission 
standards under all conditions that may reasonably be expected to occur 
in normal vehicle operation and use. The manufacturer would provide a 
detailed description of any testing, engineering analysis, and other 
information that forms the basis for the statement. This would likely 
include a variety of steady-state emission measurements not included in 
the prescribed duty cycle. It may also include a continuous trace 
showing how emissions vary during the transient test or it may include 
emission measurements during other segments of operation manufacturers 
believe is representative of the way their engines normally operate in 
the field.
    Two additional provisions are necessary to allow emission testing 
without removing engines from equipment in the field. We are proposing 
to require manufacturers to design their engines to broadcast 
instantaneous speed and torque values to the onboard computer. We are 
also proposing a requirement to add an emission sampling port 
downstream of the catalyst.
    The equipment and procedures for showing compliance with field-
testing standards also hold promise to reduce the cost of production-
line testing. Companies with production facilities that have a 
dynamometer but no emission measurement capability could use the field-
testing equipment and procedures to get a low-cost, valid emission 
measurement at the production line. Manufacturers may choose to use the 
cost advantage of the simpler measurement to sample a greater number of 
production-line engines. This would provide greater assurance of 
consistent emissions performance, but would also provide valuable 
quality-control data for overall engine performance. See the discussion 
of alternate approaches to production-line testing in Section III.C.4 
for more information.
    c. What limits are placed on field testing? The field-testing 
standards would apply to all normal operation. This could include 
steady-state or transient engine operation. Given a set of field-
testing standards, the goal for the design engineer is to ensure that 
engines are properly calibrated for controlling emissions under any 
reasonably expected mode of engine operation. Engines may not be able 
to meet the emissions limit under all conditions, however, so we are 
proposing several parameters that would narrow the range of engine 
operation that would be subject to the field-testing standards. For 
example, emission sampling for field testing would not include engine 
starting.
    Engines can often operate at extreme engine conditions (summer, 
winter, high altitude, etc.). To narrow the range of conditions for the 
design engineer, we are proposing to limit emission measurements during 
field testing to ambient temperatures from 13 deg. to 35 deg. C 
(55 deg. to 95 deg. F), and to ambient pressures from 600 to 775 
millimeters of mercury (which should cover almost all normal pressures 
from sea level to 7,000 feet above sea level). This allows testing 
under a wider range of conditions in addition to helping ensure that 
engines are able to control emissions under the whole range of 
conditions under which they operate.
    We are proposing some additional limits to define ``normal'' 
operation that could be included in field testing. These restrictions 
are intended to provide manufacturers with some certainty about what 
their design targets are and to ensure that compliance with the 
proposed field-testing standards would be feasible. These restrictions 
would apply to both variable-speed and constant-speed engine 
applications.
    First, measurements with more than 2 minutes of continuous idle 
would be excluded. This means that an emission measurement from a 
forklift while it idled for 5 minutes would not be considered valid. On 
the other hand, an emission measurement from a forklift that idled for 
1 minute (continuous or intermittent) and otherwise operated at 40 
percent power for several minutes would be considered a valid 
measurement. Measurements with in-use equipment in their normal service 
show that idle periods for Large SI engines are short, but relatively 
frequent. We should therefore not automatically exclude an emission 
sample if it includes an idling portion. At the same time, controlling 
emissions during extended idling poses a difficult design challenge, 
especially at low ambient temperatures. Exhaust and catalyst 
temperatures under these conditions can decrease enough that catalyst 
conversion rates decrease significantly. Since extended idling is not 
an appropriate focus of extensive development efforts at this stage, we 
believe the 2-minute threshold for continuous idle appropriately 
balances the need to include measurement during short idling periods 
with the technical challenges of controlling emissions under difficult 
conditions.
    Second, we are proposing that the measured power during the 
sampling period must be above 5 percent of maximum power for an 
emission measurement to be considered valid. Brake-specific emissions 
(g/kW-hr) can be very high at low power because they are calculated by 
dividing the g/hr emission rate by a very small power level (kW). By 
ensuring that brake-specific emissions are not calculated by dividing 
by power levels less than 5 percent of the maximum, we can avoid this 
problem.
    Third, gasoline-fueled engines need to run rich of stoichiometric 
combustion during extended high-load operation to protect against 
engine failure. This increases HC and CO emissions. We are accordingly 
proposing for gasoline-fueled engines that operation at 90 percent or 
more of maximum power must be less than 10 percent of the total 
sampling time. We would expect it to be uncommon for engine 
installations to call for such high power demand due to the shortened 
engine lifetime at very high-load operation. A larger engine could 
generally produce the desired power at a lower relative load, without 
compromising engine lifetime. Alternatively, applications that call for 
full-load operation typically use diesel engines. We propose to allow 
manufacturers to request a different threshold to allow more open-loop 
operation. Before we could approve

[[Page 51133]]

such a request, the engine manufacturer would need to have a plan for 
ensuring that the engines in their final installation would not 
routinely operate at loads above the specified threshold.
    Fourth, as a part of the ``normal operation'' limitation, we are 
considering a limit on the frequency of accelerations. Very frequent 
acceleration events can make it difficult to consistently get enough 
air for combustion. Engine dynamometers also place a practical limit on 
the degree of transient operation that can be simulated in the 
laboratory. It would not be appropriate to exclude normal driving 
patterns, but drawing a line at the upper end of what happens in the 
field may be an appropriate constraint for field testing. This would 
likely take the form of a maximum frequency of acceleration events 
during the emission sampling period. We request comment on defining the 
most severe accelerations that we should include in field-testing as 
normal operation.
    An additional parameter to consider is the minimum sampling time 
for field testing. A longer period allows for greater accuracy, due 
mainly to the smoothing effect of measuring over several transient 
events. On the other hand, an overly long sampling period can mask 
areas of engine operation with poor emission-control characteristics. 
To balance these concerns, we are proposing a minimum sampling period 
of 2 minutes. In other rules for diesel engines, we have allowed 
sampling periods as short as 30 seconds. Spark-ignition engines 
generally don't have turbochargers and they control emissions by 
maintaining air-fuel ratio with closed-loop controls through changing 
engine operation. Spark-ignition engines are therefore much less prone 
to consistent emission spikes from off-cycle or unusual engine 
operation. We believe the 2-minute sampling time requirement will 
ensure sufficient measurement accuracy and will allow for more 
meaningful measurements from engines that may be operated with very 
frequent but brief times at idle. We are not proposing a maximum 
sampling time. We would expect manufacturers testing in-use engines to 
select an approximate sampling time before measuring emissions. When 
selecting an engine family for the in-use testing program, we may add 
further direction related to the emission-sampling effort, such as 
sampling time or specific types of engine operation.
    We request comment on whether these are appropriate constraints on 
sampling emissions using field-testing procedures. In particular, we 
request comment on whether the limitations described are necessary or 
sufficient to target the whole range of normal operation that should be 
subject to emission standards.
    d. How do I test engines in the field? To test engines without 
removing them from equipment, analyzers would be connected to the 
engine's exhaust to detect emission concentrations during normal 
operation. Exhaust volumetric flow rate and continuous power output 
would also be needed to convert the analyzer responses to units of g/
kW-hr for comparing to emission standards. We are proposing to 
calculate these values from measurements of the engine intake flow 
rate, the exhaust air/fuel ratio and the engine speed, and from torque 
information.
    Small analyzers and other equipment are already available that 
could be adapted for measuring emissions from field equipment. A 
portable flame ionization detector could measure total hydrocarbon 
concentrations. Methane measurement currently requires more expensive 
laboratory equipment that is impractical for field measurements. Field-
testing standards would therefore be based on total hydrocarbon 
emissions. A portable analyzer based on zirconia technology measures 
NOX emissions. A nondispersive infrared (NDIR) unit could 
measure CO. Emission samples could best be drawn from the exhaust flow 
directly downstream of the catalyst material to avoid diluting effects 
from the end of the tailpipe. For this reason we request comment on a 
requirement for manufacturers to produce all their engines with this 
kind of sampling port in the exhaust pipe or at the end of the 
catalytic converter. Mass flow rates would also factor into the torque 
calculation; this could either be measured in the intake manifold or 
downstream of the catalyst.
    Calculating brake-specific emissions depends on determining 
instantaneous engine speed and torque levels. We therefore propose to 
require that manufacturers design their engines to continuously monitor 
engine speed and torque. The proposed tolerance for speed measurements, 
which is relatively straightforward is 5 percent. For 
torque, the onboard computer would need to convert measured engine 
parameters into useful units. The manufacturer would probably need to 
monitor a surrogate value such as intake manifold pressure or throttle 
position (or both), then rely on a look-up table programmed into the 
onboard computer to convert these torque indicators into newton-meters. 
Manufacturers may also want to program the look-up tables for torque 
conversion into a remote scan tool. Because of the greater uncertainty 
in these measurements and calculations, we are proposing that 
manufacturers produce their systems to report torque values that are 
within 85 and 105 percent of the true value. This broader range allows 
appropriately for the uncertainty in the measurement, while providing 
an incentive for manufacturers to make the torque reading as accurate 
as possible. Under-reporting torque values would over-predict 
emissions. These tolerances are taken into account in the selection of 
the field-testing standards, as described in Chapter 4 of the Draft 
Regulatory Support Document. We request comment on this approach to 
measuring in-use emissions and on any alternate approaches.
    We request comment on all aspects of field-testing standards and 
procedures.

E. Special Compliance Provisions

    We are proposing a variety of provisions to address the particular 
concerns of small-volume manufacturers of Large SI engines. These 
provisions are generally designed to address the limited capital and 
engineering resources of companies that produce very few engines.
    As described in Section IV.B.4, we are proposing a provision to 
allow manufacturers to certify Large SI engines to emission standards 
for engines below 19 kW if they have displacement below 1 liter and 
rated power between 19 and 30 kW. We are proposing to expand this 
flexibility to include a limited number of engines up to 2.5 liters. 
This provision would be available for manufacturers producing 300 or 
fewer Large SI engines annually nationwide for the 2004 through 2006 
model years. We request comment on this arrangement, especially in 
three areas. First, we request comment on the possible need to adjust 
the 30 kW cap for these engines to ensure that we include the 
appropriate engines. Second, we request comment on the sales threshold 
and whether a greater allowance would be necessary to accommodate the 
sales levels of small-volume manufacturers. Finally, since many of 
these engines may be used in places where individual exposure to CO 
emissions is a concern, we request comment on adopting an intermediate 
CO emission standard for these engines. The CO emission standard for 
engines rated below 19 kW is currently about 600 g/kW-hr. Engines with 
displacement between 1 and 2.5 liters generally have much lower CO 
emissions than small lawn and garden engines. Baseline emission levels 
on

[[Page 51134]]

small automotive-type engines shows that uncontrolled emission levels 
are about 130 g/kW-hr. We request comment on adopting this as a CO 
standard for engines that use the provision described in this 
paragraph.
    Starting in 2007, we propose to discontinue the provisions 
described above for engines between 1 and 2.5 liters. In their place, 
we propose to adopt for three model years the standards that would 
otherwise apply in 2004 (4 g/kW-hr HC+NOX and 50 g/kW-hr CO 
with steady-state duty cycles). Starting in 2010, there would no longer 
be separate emission standards for small-volume manufacturers. Since 
upgrading to the anticipated emission-control technology substantially 
improves performance, we expect that small-volume manufacturers may 
find it advantageous to introduce these technologies ahead of the 
schedule described here.
    We are proposing several additional provisions to reduce the burden 
of complying with emission standards; we propose to apply these 
provisions to all manufacturers. These include (1) reduced production-
line testing rates after consistent testing with good emission results, 
(2) allowance for alternative, low-cost testing methods to test 
production-line engines, (3) a flexible approach to developing 
deterioration factors, which gives the manufacturer broad discretion to 
develop appropriate emission-durability estimates.
    We are also proposing provisions to address hardship circumstances, 
as described in Section VII.C. For Large SI engines, we are proposing a 
longer available extension of the deadline for meeting emission 
standards for small-volume manufacturers. Under this provision, we 
would extend the deadline by three years for companies that qualify for 
special treatment under the hardship provisions. We would, however, not 
extend the deadline for compliance beyond the three-year period. This 
approach considers the fact that, unlike most other engine categories, 
qualifying small businesses are more likely to be manufacturers 
designing their own products. Other types of engines more often involve 
importers, which are limited more by available engine suppliers than 
design or development schedules.

F. Technological Feasibility of the Standards

    Our general goal in designing the proposed standards is to develop 
a program with technologically feasible standards that will achieve 
significant emission reductions. Our standards must comply with Clean 
Air Act section 213(a)(3), as described in Section III.B. The Act also 
instructs us to first consider standards equivalent in stringency to 
standards for comparable motor vehicles or engines (if any) regulated 
under section 202 of the Act, taking into consideration technological 
feasibility, costs, and other factors (the relevant engines regulated 
under section 202 are automotive and highway truck engines). We are 
proposing emission standards that depend on the industrial versions of 
established automotive technologies. The most recent advances in 
automotive technology have made possible even more dramatic emission 
reductions. However, we believe that transferring some of these most 
advanced technologies would not be appropriate for nonroad engines at 
this time, especially considering the much smaller sales volumes for 
amortizing fixed costs and the additional costs associated with the 
first-time regulation of these engines. On the other hand, the proposed 
emission standards for Large SI align well with standards we have 
adopted for the next tier of heavy-duty highway gasoline engines (64 FR 
58472, October 29, 1999). We have also adopted long-term standards for 
these engines that require significant further reductions with more 
sophisticated technologies (66 FR 5002, January 18, 2001).
    To comply with the 2004 model year standards, manufacturers should 
not need to do any development, testing, or certification work that is 
not already necessary to meet California ARB standards in 2004. As 
shown in Chapter 4 of the Draft Regulatory Support Document, 
manufacturers can meet these standards with three-way catalysts and 
closed-loop fuel systems. These technologies have been available for 
industrial engine applications for several years. Moreover, several 
manufacturers have already completed the testing effort to certify with 
California ARB that their engines meet these standards. Complying with 
the proposed standards nationwide in 2004 would therefore require 
manufacturers only to produce greater numbers of the engines complying 
with the California standards.
    Chapter 4 of the Draft Regulatory Support Document further 
describes data and rationale showing why we believe that the proposed 
2007 model year emission standards under the steady-state and transient 
duty-cycles and field-testing procedures are feasible. In summary, SwRI 
testing and other data show that the same catalyst and fuel-system 
technologies needed to meet the 2004 standards can be optimized to meet 
more stringent emission standards. Applying further development allows 
the design engineer to fine-tune control of air-fuel ratios and address 
any high-emission modes of operation to produce engines that 
consistently control emissions to very low levels, even considering the 
wide range of operation experienced by these engines. The proposed 
numerical emission standards are based on measured emission levels from 
engines that have operated for at least 5,000 hours with a functioning 
emission-control system. These engines demonstrate the achievable level 
of control from catalyst-based systems and provide a significant degree 
of basic development that should help manufacturers in optimizing their 
own engines.
    We believe it is appropriate to initiate the second stage of 
standards in 2007, because we believe that applying these emission 
standards earlier would not allow manufacturers enough stability 
between introduction of different phases of emission standards to 
amortize their fixed costs and prepare for complying with the full set 
of requirements proposed in this notice. Three years of stable emission 
standards, plus the remaining lead time before 2004, allows 
manufacturers enough time to go through the development and 
certification effort to comply with the proposed standards. The 
proposed provisions to allow ``family banking'' for early compliance 
should provide an additional tool for companies that choose to spread 
out their design and certification efforts.
    The proposed emission standards would either have no impact or a 
positive impact with respect to noise, energy, and safety, as described 
in Chapter 4 of the Draft Regulatory Support Document. In particular, 
the anticipated fuel savings associated with the expected emission-
control technologies would provide a very big energy benefit related to 
new emission standards. The projected technologies are currently 
available and are consistent with those anticipated for complying with 
the emission standards adopted by California ARB. The lead time for the 
proposed interim and final emission standards allows manufacturers 
enough time to optimize these designs to most effectively reduce 
emissions from the wide range of Large SI equipment applications.

V. Recreational Marine Diesel Engines

    This section describes the new provisions proposed for 40 CFR part 
94, which would apply to engine manufacturers and other certificate 
holders. This section also discusses

[[Page 51135]]

proposed test equipment and procedures for anyone who tests engines to 
show they meet emission standards. We are proposing the same general 
compliance provisions from 40 CFR part 94 for engine manufacturers, 
equipment manufacturers, operators, rebuilders, and others. Similar 
general compliance provisions are described for the other engines 
included in this proposal in Section VII. See Section III for a 
description of our general approach to regulating nonroad engines and 
how manufacturers show that they meet emission standards.

A. Overview

    We are proposing exhaust and crankcase emission standards for 
recreational marine diesel engines with power ratings greater than or 
equal to 37 kW. We are proposing emission standards for hydrocarbons 
(HC), oxides of nitrogen ( NOX), carbon monoxide (CO), and 
particulate matter (PM) beginning in 2006. We believe manufacturers 
will be able to use technology developed for use on land-based nonroad 
and commercial marine diesel engines. To encourage the introduction of 
low-emission technology, we are also proposing voluntary ``Blue Sky'' 
standards which are 40 percent lower than the proposed standards. We 
also recognize that there are many small businesses that manufacture 
recreational marine diesel engines; we are therefore proposing several 
regulatory flexibility options for small businesses that should help 
minimize any unique burdens caused by emission regulation. A history of 
environmental regulation for marine engines is presented in Section I.
    We have determined there are at least 16 companies manufacturing 
marine diesel engines for recreational vessels. Six of the identified 
companies are considered small businesses as defined by the Small 
Business Administration (fewer than 1000 employees). Nearly 75 percent 
of diesel engines sales for recreational vessels in 2000 can be 
attributed to three large companies. Based on sales estimates for 2000, 
the six small businesses represent approximately 4 percent of 
recreational marine diesel engine sales. The remaining companies each 
comprise between two and seven percent of sales for 2000.
    Diesel engines are primarily available in inboard marine 
configurations, but may also be available in sterndrive and outboard 
marine configurations. Inboard diesel engines are the primary choice 
for many larger recreational boats.

B. Engines Covered by This Proposal

    The standards we are proposing in this section apply to 
recreational marine diesel engines. These engines were excluded from 
our final standards for commercial marine diesel engines finalized in 
1999 because we thought their operation in planing mode might impose 
design requirements on recreational boat builders (64 CFR 73300, 
December 29, 1999). Commercial marine vessels tend to be displacement-
hull vessels, designed and built for a unique commercial application 
(e.g., towing, fishing, general cargo). Power ratings for engines used 
on these vessels are analogous to land-based applications, and these 
engines are generally warranted for 2,000 to 5,000 hours of use. 
Recreational vessels, on the other hand, tend to be planing vessels, 
and engines used on these vessels are designed to achieve higher power 
output with less engine weight. This increase in power reduces the 
lifetime of the engine; recreational marine engines are therefore 
warranted for fewer hours of operation than their commercial 
counterparts. In our previous rulemaking, recreational engine industry 
representatives raised concerns about the ability of these engines to 
meet the standards without substantial changes in the size and weight 
of the engine. Such changes could have an impact on vessel builders, 
who might have to redesign vessel hulls to accommodate the new engines. 
Because most recreational vessel hulls are made on fiberglass molds, 
this could be a significant burden for recreational vessel builders.
    Since we finalized the commercial marine diesel engine standards, 
we determined that recreational marine diesel engines can achieve those 
same emission standards without significant impacts on engine size and 
weight. Section V.G of this document and Chapters 3 and 4 of the Draft 
Regulatory Support Document describe the several technological changes 
we anticipate manufacturers will use to comply with the new emission 
standards. None of these technologies has an inherent negative effect 
on the performance or power density of an engine. As with engines in 
land-based applications, we expect that manufacturers will be able to 
use the range of technologies available to maintain or even improve the 
performance capabilities of their engines. We are nevertheless 
proposing to establish a separate program for recreational marine 
diesel engines in this rule. This will allow us to tailor certain 
aspects of the program to these applications, notably the not-to-exceed 
requirements. We seek comment on whether this approach is appropriate 
or if we should remove the distinction and apply identical emission-
control requirements to both commercial and recreational marine diesel 
engines.
    To distinguish between commercial and recreational marine diesel 
engines for the purpose of emission controls, it is necessary to define 
``recreational marine diesel engine.'' According to the definition we 
finalized in our commercial marine diesel engine rule, recreational 
marine engine means a propulsion marine engine that is intended by the 
manufacturer to be installed on a recreational vessel. The engine must 
be labeled to distinguish it from a commercial marine diesel engine. 
The label must read: ``THIS ENGINE IS CATEGORIZED AS A RECREATIONAL 
ENGINE UNDER 40 CFR PART 94. INSTALLATION OF THIS ENGINE IN ANY 
NONRECREATIONAL VESSEL IS A VIOLATION OF FEDERAL LAW SUBJECT TO 
PENALTY.''
    We are also including in the proposed definition that a 
recreational marine engine must be a Category 1 marine engine (have a 
displacement of less than 5 liters per cylinder). One manufacturer 
commented after the ANPRM that only engines less than 2.5 liters per 
cylinder in displacement should be considered recreational. We request 
comment on this size cut-off and we request comment on allowing 
manufacturers flexibility in defining the upper limit of their 
recreational product line provided that it is between 2.5 and 5 liters 
per cylinder.
    For the purpose of the recreational marine diesel engine 
definition, recreational vessel was defined as ``a vessel that is 
intended by the vessel manufacturer to be operated primarily for 
pleasure or leased, rented, or chartered to another for the latter's 
pleasure.'' To put some boundaries on that definition, since certain 
vessels that are used for pleasure may have operating characteristics 
that are more similar to commercial marine vessels (e.g., excursion 
vessels and charter craft), we drew on the Coast Guard's definition of 
a ``small passenger vessel'' (46 U.S.C 2101(35)) to further delineate 
what would be considered to be a recreational vessel. Specifically, the 
term ``operated primarily for pleasure or leased, rented or chartered 
to another for the latter's pleasure'' would not include the following 
vessels: (1) Vessels of less than 100 gross tons that carry more than 6 
passengers; (2) vessels of 100 gross tons or more than carry one or 
more passengers; or (3) vessels used solely for competition. For the 
purposes

[[Page 51136]]

of this definition, a passenger is defined by 46 U.S.C 2101 (21, 21a) 
which generally means an individual who pays to be on the vessel.
    We received several comments in response to the ANPRM on these 
definitions. Engine manufacturers were concerned that the definitions 
may be unworkable for engine manufacturers, since they cannot know 
whether a particular recreational vessel might carry more than six 
passengers at a time. All they can know is whether the engine they 
manufacture is intended by them for installation on a vessel designed 
for pleasure and having the planing, power density and performance 
requirements that go along with that use.
    We responded to similar concerns in the Summary and Analysis of 
Comments for the commercial marine diesel engine rule, explaining that 
a vessel would be considered a recreational vessel if the boat builder 
intends that the customer will operate the boat consistent with the 
recreational-vessel definition.\132\ Relying on the boat builder's 
intent is necessary since manufacturers need to establish a vessel's 
classification before it is sold, whereas the Coast Guard definitions 
apply at the time of use. The definition therefore relies on the intent 
of the boat builder to establish that the vessel will be used 
consistent with the above criteria. If a boat builder manufactures a 
vessel for a customer who intends to use the vessel for recreational 
purposes, we would always consider that a recreational vessel 
regardless of how the owner (or a subsequent owner) actually uses it.
---------------------------------------------------------------------------

    \132\ Summary and Analysis of Comments: Control of Emissions 
from Marine Diesel Engines. EPA420-R-99-028, November 1999, Docket 
A-97-50, document V-C-1.
---------------------------------------------------------------------------

    We are proposing to retain our existing definition of recreational 
marine vessel. We request comment on all aspects of this definition. We 
are also requesting comment on how to verify the validity of the vessel 
manufacturer's original intent. One option, as noted in the Summary and 
Analysis of Comments for the previous rule, would be written assurance 
from the buyer.
    We are also requesting comment on two alternative approaches for 
the definition of recreational marine vessel that were suggested by 
ANPRM commenters. The first recommends that we follow the definition in 
46 U.S.C. 2101(25), which defines a recreational vessel as one ``being 
manufactured or operated primarily for pleasure, or leased, rented, or 
chartered to another for the latter's pleasure.''\133\ The second 
recommends that we define recreational vessel as one (1) which by 
design and construction is intended by the manufacturer to be operated 
primarily for pleasure, or to be leased, rented, or chartered to 
another for the latter's pleasure; and (2) whose major structural 
components are fabricated and assembled in an indoor production-line 
manufacturing plant or similar land-side operation and not in a dry 
dock, graving dock, or marine railway on the navigable waters of the 
United States.\134\ We request comment on whether either of these 
definitions is preferable to the existing definition and, more 
specifically, on whether either of these alternative definitions would 
be sufficient to ensure that recreational marine diesel engines are 
installed on vessels that will be used only for recreational purposes.
---------------------------------------------------------------------------

    \133\ Statement of the Engine Manufacturers Association, Docket 
A-2000-01, Document No. II-D-33.
    \134\ Comments of the National Marine Manufacturers Association, 
Docket A-2000-01, Document II-D-27.
---------------------------------------------------------------------------

C. Proposed Standards for Marine Diesel Engines

    We are proposing technology-forcing emission standards for new 
recreational marine diesel engines with rated power greater than or 
equal to 37 kW. This section describes the proposed standards and 
implementation dates and gives an outline of the technology that can be 
used to achieve these levels. We request comment on these standards and 
dates. In particular, commenters should address whether the dates 
provide sufficient lead time. The technological feasibility discussion 
below (Section V.G) describes our technical rationale in more detail.
1. What Are the Proposed Standards and Compliance Dates?
    To propose emission standards for recreational marine diesel 
engines, we first considered the Tier 2 standards for commercial marine 
diesel engines. Recreational marine diesel engines can use all the 
technologies projected for Tier 2 and many of these engines already use 
this technology. This includes electronic fuel management, 
turbocharging, and separate-circuit aftercooling. In fact, because 
recreational engines have much shorter design lives than commercial 
engines, it is easier to apply raw-water aftercooling to these engines, 
which allows manufacturers to enhance performance while reducing 
NOX emissions.
    Engine manufacturers will generally increase the fueling rate in 
recreational engines, compared to commercial engines, to gain power 
from a given engine size. This helps bring a planing vessel onto the 
water surface and increases the maximum vessel speed without increasing 
the weight of the vessel. This difference in how recreational engines 
are designed and used affects emissions.
    We are proposing to implement the commercial marine engine 
standards for recreational marine diesel engines, allowing two years 
beyond the dates that standards apply for the commercial engines. This 
would provide engine manufacturers with additional lead time in 
adapting technology to their recreational marine diesel engines. The 
proposed standards and implementation dates for recreational marine 
diesel engines are presented in Table V.C-1. The subcategories refer to 
engine displacement in liters per cylinder.

            Table V.C-1.--Proposed Recreational CI Marine Emission Standards and Implementation Dates
----------------------------------------------------------------------------------------------------------------
                                                               HC+NOX  g/                             Implemen-
                         Subcategory                             kW-hr     PM  g/kW-hr  CO  g/kW-hr  tation date
----------------------------------------------------------------------------------------------------------------
power  37 kW.....................................          7.5         0.40          5.0         2007
0.5  disp  0.9
0.9  disp  1.2...................................          7.2         0.30          5.0         2006
1.2  disp  2.5...................................          7.2         0.20          5.0         2006
disp  2.5........................................          7.2         0.20          5.0         2009
----------------------------------------------------------------------------------------------------------------

[[Page 51137]]

2. Will I Be Able To Average, Bank, or Trade Emissions Credits?
    Section III.C.3 gives an overview of the proposed emission-credit 
program, which is consistent with what we adopted for Category 1 
commercial marine diesel engines. We are proposing that the emission-
credit program be limited to HC+NOX and PM emissions.
    Consistent with our land-based nonroad and commercial marine diesel 
engine regulations, we are proposing to disallow simultaneous 
generation of HC+NOX credits and use of PM credits on the 
same engine family, and vice versa. This is necessary because of the 
inherent trade-off between NOX and PM emissions in diesel 
engines. We request comment on whether an engine should be allowed to 
generate credits on one pollutant while using credits on another, and 
whether allowing such an additional flexibility would necessitate a 
reconsideration of the stringency of the proposed emission limits.
    We are proposing the same maximum value of the Family Emission 
Limit (FEL) as for commercial marine diesel engines. For engines with a 
displacement of less than 1.2 liters/cylinder, the maximum values are 
11.5 g/kW-hr HC+NOX and 1.2 g/kW-hr PM; for larger engines, 
the maximum values are 10.5 g/kW-hr HC+NOX and 0.54 g/kW-hr 
PM. These maximum FEL values were based on the comparable land-based 
emission-credit program and will ensure that the emissions from any 
given family certified under this program not be significantly higher 
than the applicable emission standards. We believe these proposed 
maximum values will prevent backsliding of emissions above the baseline 
levels for any given engine model. Also, we are concerned that the 
higher emitting engines could result in emission increases in areas 
such as ports that may have a need for PM or NOX emission 
reductions. Balancing this concern is the fact that recreational marine 
diesel engines constitute a small fraction of PM and HC+NOX 
emissions in nonattainment areas. Thus, if a few engine families have 
higher emissions then our proposed FEL cap, the incremental emissions 
in these areas may not be significant. Also, if we do not promulgate 
FEL caps for this category, manufacturers will need to offset high 
emitting engines with low-emitting engines to meet the average 
standard. We are interested in comments on these issues, on the degree 
to which FEL caps would hinder manufacturer flexibility and impose 
costs, and the environmental impact of FEL caps. We ask commenters to 
address whether we should promulgate FEL caps.
    As an alternative, we are requesting comment on whether we should 
consider using the MARPOL Annex VI NOX standard as the 
appropriate NOX FEL upper limit. Under this approach we 
would continue to use the land-based Tier 1 PM standard as the 
recreational marine diesel engine FEL upper limit. As part of this 
approach we would have to accommodate the fact that the MARPOL Annex VI 
standard is for NOX only and these proposed standards are 
HC+NOX. We further request comment under this approach as to 
how best to deal with this inconsistency.
    We are proposing that emission credits generated under this program 
have no expiration, with no discounting applied. This is consistent 
with the commercial marine credit program and gives manufacturers 
greater flexibility in implementing their engine designs. However, if 
we were to revisit the standards proposed today at a later date, we 
would have to reevaluate this issue in the context of spillover of 
credits in the new program.
    Consistent with the land-based nonroad diesel rule, we are also 
proposing to disallow using credits generated on land-based engines for 
demonstrating compliance with marine diesel engines. In addition, we 
propose that credits may not be exchanged between recreational and 
commercial marine engines. We are concerned that manufacturers 
producing land-based and/or commercial marine engines in addition to 
recreational marine engines could effectively trade out of the 
recreational marine portion of the program, thereby potentially 
obtaining a competitive advantage over small companies selling only 
recreational marine engines. In addition, there are two differences in 
the way that land-based, commercial marine, and recreational marine 
credits are calculated that make the credits somewhat incompatible. The 
first is that the difference in test duty cycles means there is an 
difference in calculated load factors for each of these categories of 
engines. The second is that there are significant differences in the 
useful lives. EPA seeks comment on the need for these restrictions and 
on the degree to which imposing them may create barriers to low-cost 
emission reductions.
    We are proposing to allow early banking of emission credits once 
this rule is finalized. We believe that early banking of emission 
credits will allow for a smoother implementation of the recreational 
marine standards. These credits are generated relative to the proposed 
standards and are undiscounted. We are aware that there are already 
some marine diesel engines that meet the proposed standards, and we are 
concerned about windfall credits from engines that generate early 
credits without any modifications to reduce emissions. We request 
comment on whether or not these engines should be able to generate 
credits.
    We also propose that manufacturers have the option of generating 
credits relative to their pre-control emission levels. If manufacturers 
choose this option they will have to develop engine family-specific 
baseline emission levels. Credits will then be calculated relative to 
the manufacturer-generated baseline emission rates, rather than the 
standards. To generate the baseline emission rates, a manufacturer must 
test three engines from the family for which the baseline is being 
generated. The baseline will be the average emissions of the three 
engines. Under this option, engines must still meet the proposed 
standards to generate credits, but the credits will be calculated 
relative to the generated baseline rather than the standards. However, 
any credits generated between the level of the standards and the 
generated baseline will be discounted 10 percent. This is to account 
for the variability of testing in-use engines to establish the family-
specific baseline levels, which may result from differences in hours of 
use and maintenance practices. We request comment on all aspects of the 
proposed emission-credit program.
    One engine manufacturer commented after the ANPRM that all their 
recreational engine product lines fall into the per-cylinder 
displacement range with the proposed implementation date of 2006. This 
manufacturer expressed concern that it would be burdensome to introduce 
all their product lines at one time and presented the idea of phasing 
in their product lines from 2005 through 2007 instead. An alternative 
to early banking or a revised phase-in would be ``family-banking.'' 
Under the ``family-banking'' concept, we would allow manufacturers to 
certify an engine family early. For each year of certifying an engine 
family early, the manufacturer would be able to delay certification of 
a smaller engine family by one year. This would be based on the actual 
sales of the early family and the projected sales volumes of the late 
family; this would require no calculation or accounting of emission 
credits. We request comment on this approach or any other approach that 
would help manufacturers bring the product lines into compliance to the 
proposed standards without

[[Page 51138]]

compromising emissions reductions (see Sec. 1048.145 of the proposed 
regulations).
3. Is EPA Proposing Voluntary Standards for These Engines?
    a. Blue Sky. Section III.B.5 gives an overview of Blue Sky 
voluntary standards. We are proposing to target about a 45-percent 
reduction beyond the mandatory standards as a qualifying level for Blue 
Sky Series engines to match the voluntary standards already adopted for 
commercial marine diesel engines (see Table V.C-2). While the Blue Sky 
Series emission standards are voluntary, a manufacturer choosing to 
certify an engine under this program must comply with all the 
requirements proposed for this category of engines, including allowable 
maintenance, warranty, useful life, rebuild, and deterioration factor 
provisions. This program would become effective immediately once we 
finalize this rule. We request comment on the Blue Sky Series approach 
as it would apply to recreational marine diesel engines.

  Table V.C.-2.--Blue Sky Voluntary Emission Standards for Recreational
                          Marine Diesel Engines
                                [g/kW-hr]
------------------------------------------------------------------------
                 Rated Brake Power  (kW)                   HC+NOX    PM
------------------------------------------------------------------------
power  37 kW..................................    4.0    0.24
displ.0.9
0.9displ.1.2..................................    4.0    0.18
1.2displ.2.5..................................    4.0    0.12
2.5displ......................................    5.0    0.12
------------------------------------------------------------------------

    b. MARPOL Annex VI. The MARPOL Annex VI standards are discussed 
above in Section I.F.3 for marine diesel engines rated above 130 kW. We 
are not proposing to adopt the MARPOL Annex VI NOX emission 
limits as Clean Air Act standards at this time. However, we encourage 
engine manufacturers to make Annex VI-compliant engines available and 
boat builders to purchase and install them prior to the implementation 
of our proposed standards. If the international standards are ratified 
in the U.S., they would go into effect retroactively to all boats built 
January 1, 2000 or later. One advantage of using MARPOL-compliant 
engines is that if this happens, users will be in compliance with the 
standard without having to make any changes to their engines.
    To encourage boat manufacturers to purchase MARPOL Annex VI-
compliant engines prior to the date the Annex goes into force for the 
United States, we are proposing a voluntary certification program that 
will allow engine manufacturers to obtain a Statement of Voluntary 
Compliance to the MARPOL Annex VI NOX limits. This voluntary 
approach to the MARPOL Annex VI emission limits depends on the 
assumption that manufacturers will produce MARPOL-compliant engines 
before the emission limits go into effect internationally. Engine 
manufacturers can use this voluntary certification program to obtain a 
Statement of Voluntary Compliance to the MARPOL NOX 
limits.\135\
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    \135\ For more information about our voluntary certification 
program, see ``guidance for Certifying to MARPOL Annex VI,'' VPCD-
99-02. This letter is available on our website: http://www.epa.gov/
otaq/regs/nonroad/marine/ci/imolettr.pdf.
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    We request comment on whether or not we should apply the MARPOL 
Annex VI standards as a first Tier to this proposed regulation. We also 
request comment on reasons for whether or not the MARPOL Annex VI 
standards should apply to recreational marine at all.
4. What Durability Provisions Apply?
    There are several related provisions that would be needed to ensure 
that emission control would be maintained throughout the life of the 
engine. Section III gives a general overview of durability provisions 
associated with emissions certification. This section discusses these 
proposed provisions specifically for recreational marine diesel 
engines.
    a. How long would my engine have to comply? We propose to require 
that manufacturers produce engines that comply over the full useful 
life of ten years or until the engine accumulates 1,000 operating 
hours, whichever occurs first. We would consider the hours requirement 
to be a minimum value for useful life, and would require manufacturers 
to comply for a longer period in those cases where they design their 
engines to be operated longer than 1,000 hours. In making the 
determination that engines are designed to last longer than the 
proposed hour limit, we would look for evidence that the engines 
continue to reliably deliver the necessary power output without an 
unacceptable increase in fuel consumption.
    b. How would I demonstrate emission durability? We are proposing 
the same durability demonstration requirements for recreational marine 
diesel engines as already exist for commercial marine diesel engines. 
This means that recreational marine engine manufacturers, using good 
engineering judgment, would generally need to test one or more engines 
for emissions before and after accumulating 1,000 operating hours 
(usually performed by continuous engine operation in a laboratory). The 
results of these tests are referred to as ``durability data,'' and are 
used to determine the rates at which emissions are expected to increase 
over the useful life of the engine for each engine family (the rates 
are known as deterioration factors). However, in many cases, 
manufacturers would be allowed to use durability data from a different 
engine family, or for the same engine family in a different model year. 
Because of this allowance to use the same data for multiple engine 
families, we expect durability testing to be very limited.
    We are also proposing the same provisions from the commercial 
marine rulemaking for how durability data are to be collected and how 
deterioration factors are to be generated. These requirements are in 40 
CFR 94.211, 94.218, 94.219, and 94.220. These sections describe when 
durability data from one engine family can be used for another family, 
how to select to the engine configuration that is to be tested, how to 
conduct the service accumulation, and what maintenance can be performed 
on the engine during this service accumulation.
    c. What maintenance would be allowed during service accumulation? 
For engines certified to a 1,000-hour useful life, the only maintenance 
that would be allowed is regularly scheduled maintenance unrelated to 
emissions that is technologically necessary. This could typically 
include changing engine oil, oil filter, fuel filter, and air filter. 
We request comment on the allowable maintenance during service 
accumulation.
    d. Would production-line testing be required? We are proposing to 
apply the production-line testing requirements for commercial marine 
engines to recreational marine diesel engines, with the additional 
provisions described in Section III.C.4. A manufacturer would have to 
test one percent of its total projected annual sales of Category 1 
engines each year to meet production-line testing requirements. We are 
proposing that manufacturers combine recreational and commercial engine 
families in calculating their sample sizes for production-line testing. 
We are not proposing a minimum number of tests, so a manufacturer could 
produce up to 100 marine diesel engines without doing any production-
line testing.
5. Do These Standards Apply to Alternative-Fueled Engines?
    These proposed standards apply to all recreational marine diesel 
engines,

[[Page 51139]]

without regard to the type of fuel used. While we are not aware of any 
alternative-fueled recreational marine engines that are currently being 
sold into the U.S. market, we are proposing alternate forms of the 
hydrocarbon standards to address the potential for natural gas-fueled 
and alcohol-fueled engines. In our regulation of highway vehicles and 
engines, we determined it is not appropriate to apply total hydrocarbon 
standards to engines fueled with natural gas (which is comprised 
primarily of methane), but rather that nonmethane hydrocarbon (NMHC) 
standards should be used (59 FR 48472, September 21, 1994). These 
alternate forms follow the precedent set in previous rulemakings to 
make the standards similar in stringency and environmental impact.
    Similarly, we determined that alcohol-fueled highway engines and 
vehicles should be subject to HC-equivalent (HCE) standards instead of 
HC standards (54 FR 14426, April 11, 1989). HC-equivalent emissions are 
calculated from the oxygenated organic components and non-oxygenated 
organic components of the exhaust, summed together based on the amount 
of organic carbon present in the exhaust. Thus, we are proposing that 
alcohol-fueled recreational marine engines comply with total 
hydrocarbon equivalent (THCE) plus NOX standards instead of 
THC plus NOX standards.
6. Is EPA Controlling Crankcase Emissions?
    We are proposing to require manufacturers to prevent crankcase 
emissions from recreational marine diesel engines, with one exception. 
We are proposing to allow turbocharged recreational marine diesel 
engines to be built with open crankcases, as long as the crankcase 
ventilation system allows measurement of crankcase emissions. For these 
engines with open crankcases, we will require crankcase emissions to be 
either routed into the exhaust stream to be included in the exhaust 
measurement, or to be measured separately and added to the measured 
exhaust mass. These measurement requirements would not add 
significantly to the cost of testing, especially where the crankcase 
vent is simply routed into the exhaust stream prior to the point of 
exhaust sampling. This proposal is consistent with our previous 
regulation of crankcase emissions from such diverse sources as 
commercial marine engines, locomotives, and passenger cars.
7. What Are the Smoke Requirements?
    We are not proposing smoke requirements for recreational marine 
diesel engines. Marine diesel engine manufacturers have stated that 
many of their engines, though currently unregulated, are manufactured 
with smoke limiting controls at the request of customers. Users seek 
low smoke emissions both because they dislike the exhaust residue on 
decks and because they can be subject to penalties in ports with smoke 
emission requirements. In many cases, marine engine exhaust gases are 
mixed with water prior to being released. This practice reduces smoke 
visibility. Moreover, we believe the PM standards proposed here for 
diesel engines will have the effect of limiting smoke emissions as 
well. We request comment on this position and, specifically, on whether 
there is a need at this time for additional control of smoke emissions 
from recreational marine diesel engines, and if so, what the 
appropriate limits should be.
    We also request comment on an appropriate test procedure for 
measuring smoke emissions, in case we choose to pursue smoke limits. 
There is currently no established test procedure for a marine engine to 
measure compliance with a smoke limit. Most propulsion marine engines 
operate over a torque curve governed by the propellor. Consequently, a 
vessel with an engine operating at a given speed will have a narrow 
range of torque levels. Some large propulsion marine engines have 
variable-pitch propellers, in which case the engine operates much like 
constant-speed engines. Note that the International Organization for 
Standardization (ISO) is working on a proposed test procedure for 
marine diesel engines.\136\ As this procedure is finalized by ISO and 
emission data become available, we may review the issue of smoke 
requirements for all marine diesel engines. We request comment on this 
overall approach to smoke emissions from marine diesel engines, as well 
as comment on the draft ISO procedures.
---------------------------------------------------------------------------

    \136\ International Standards Organization, 8178-4, 
``Reciprocating internal combustion engines--Exhaust emission 
measurement--Part 4: Test cycles for different engine 
applications,'' Docket A-2000-01, Document II-A-19.
---------------------------------------------------------------------------

8. What Are the Proposed Not-To-Exceed Standards and Related 
Requirements?
    We are proposing not-to-exceed requirements similar to those 
finalized for commercial marine diesel engines. At the time of 
certification, manufacture would have to submit a statement that its 
engines will comply with these requirements under all conditions that 
may reasonably be expected to occur in normal vessel operation and use. 
The manufacturer would provide a detailed description of all testing, 
engineering analysis, and other information that forms the basis for 
the statement. This certification could be based on testing or on other 
research which could be used to support such a statement that is 
consistent with good engineering judgment. We request comment on 
applying the proposed NTE requirements to recreational marine diesel 
engines and on the application of the requirements to these engines.
    a. Concept. Our goal is to achieve control of emissions over the 
broad range of in-use speed and load combinations that can occur on a 
recreational marine diesel engine so that real-world emission control 
is achieved, rather than just controlling emissions under certain 
laboratory conditions. An important tool for achieving this goal is an 
in-use program with an objective standard and an easily implemented 
test procedure. Prior to this concept, our approach has been to set a 
numerical standard on a specified test procedure and rely on the 
additional prohibition of defeat devices to ensure in-use control over 
a broad range of operation not included in the test procedure.
    We are proposing to apply the defeat device provisions established 
for commercial marine engines to recreational marine diesel engines in 
addition to the NTE requirements (see 40 CFR 94.2). A design in which 
an engine met the standard at the steady-state test points but was 
intentionally designed to approach the NTE limit everywhere else would 
be considered to be defeating the standard. Electronic controls that 
recognize when the engine is being tested for emissions and adjust the 
emissions from the engine would be an example of a defeat device, 
regardless of the emissions performance of the engine.
    No single test procedure can cover all real-world applications, 
operations, or conditions. Yet to ensure that emission standards are 
providing the intended benefits in use, we must have a reasonable 
expectation that emissions under real-world conditions reflect those 
measured on the test procedure. The defeat-device prohibition is 
designed to ensure that emission controls are employed during real-
world operation, not just under laboratory or test-procedure 
conditions. However, the defeat-device prohibition is not a quantified 
standard and does not have an associated test procedure, so it does not 
have the clear objectivity and ready

[[Page 51140]]

enforceability of a numerical standard and test procedure. As a result, 
using a standardized test procedure alone makes it harder to ensure 
that engines will operate with the same level of control in the real 
world as in the test cell.
    Because the ISO E5 duty cycle uses only five modes on an average 
propeller curve to characterize marine engine operation, we are 
concerned that an engine designed to the duty cycle would not 
necessarily perform the same way over the range of speed and load 
combinations seen on a boat. These duty cycles are based on average 
propeller curves, but a propulsion marine engine may never be fitted 
with an ``average propeller.'' For instance, an engine fit to a 
specific boat may operate differently based on how heavily the boat is 
loaded.
    To ensure that emissions are controlled from recreational marine 
engines over the full range of speed and load combinations seen on 
boats, we propose to establish a zone under the engine's power curve 
where the engine may not exceed a specified emission limit. This limit 
would apply to all of the regulated pollutants under steady-state 
operation. In addition, we propose that the whole range of real ambient 
conditions be included in this ``not-to-exceed'' (NTE) zone testing. 
The NTE zone, limit, and ambient conditions are described below.
    We believe there are significant advantages to taking this 
approach. The test procedure is very flexible so it can represent the 
majority of in-use engine operation and ambient conditions. Therefore, 
the NTE approach takes all of the benefits of a numerical standard and 
test procedure and expands it to cover a broad range of conditions. 
Also, laboratory testing makes it harder to perform in-use testing 
because either the engines would have to be removed from the vessel or 
care would have to be taken that laboratory-type conditions can be 
achieved on the vessel. With the NTE approach, in-use testing and 
compliance become much easier since emissions may be sampled during 
normal vessel use. Because this approach is objective, it makes 
enforcement easier and provides more certainty to the industry of what 
is expected in use versus over a fixed laboratory test procedure.
    Even with the NTE requirements, we believe it is still important to 
retain standards based on the steady-state duty cycles. This is the 
standard that we expect the certified marine engines to meet on average 
in use. The NTE testing is more focused on maximum emissions for 
segments of operation and should not require additional technology 
beyond what is used to meet the proposed standards. We believe basing 
the emission standards on a distinct cycle and using the NTE zone to 
ensure in-use control creates a comprehensive program. In addition, the 
steady-state duty cycles give a basis for calculating credits for 
averaging, banking, and trading.
    b. Shape of the NTE zone. Figure V-C-1 illustrates our proposed NTE 
zone for recreational marine diesel engines. We based this zone on the 
range of conditions that these engines could typically see in use. 
Also, we propose to divide the zone into subzones of operation which 
have different limits as described below. Chapter 4 of the Draft 
Regulatory Support Document describes the development of the boundaries 
and conditions associated with the proposed NTE zone. We request 
comment on the proposed NTE zone.
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP05OC01.000

BILLING CODE 6560-50-C
    We propose to allow manufacturers to petition to adjust the size 
and shape of the NTE zone for certain engines if they can certify that 
the engine will not see operation outside of the revised NTE zone in 
use. This way, manufacturers could avoid having to test their engines 
under operation that they would never see in use. However, 
manufacturers would still be responsible for all operation of an engine 
on a vessel that

[[Page 51141]]

would reasonably be expected to be seen in use and would be responsible 
for ensuring that their specified operation is indicative of real-world 
operation. In addition, if a manufacturer designs an engine for 
operation at speeds and loads outside of the proposed NTE zone (i.e., 
variable-speed engines used with variable-pitch propellers), the 
manufacturer would be responsible for notifying us so their NTE zone 
can be modified appropriately to include this operation.
    c. Transient operation. We are proposing that only steady-state 
operation be included in the NTE testing. We are basing the test for 
determining certification emissions levels on the ISO E5 steady-state 
duty cycles. The goal of the NTE, for this proposal, is to cover the 
operation away from the five modes on the assumed propeller curve. Our 
understanding is that the majority of marine engine operation is 
steady-state; however, we recognize that recreational marine use would 
likely be more transient than commercial marine use. At this time we do 
not have enough data on marine engine operation to accurately determine 
the amount of transient operation that occurs. We are aware that the 
high-load transient operation seen when a boat comes to plane would not 
be included in the NTE zone as defined, even if we would require 
compliance with NTE standards during transient operation. We are also 
aware that these speed and load points could not be achieved under 
steady-state operation for a properly loaded boat in use.
    Our proposal to exclude transient operation from NTE testing is 
consistent with the commercial marine diesel requirements. Also, the 
proposed standards are technology-forcing and are for a previously 
unregulated industry. We believe excluding transient operation will 
simplify the requirements on this industry while still maintaining 
proportional emission reductions due to the technology-forcing nature 
of this proposal. We intend to study marine operation to understand 
better the effects of transient operation on emissions. If we find that 
excluding transient operation from the compliance requirements results 
in a significant increase in emissions, we will revisit this provision 
in the future. We request comment on the appropriateness of excluding 
transient operation from NTE requirements.
    d. Emission standards. We are proposing emission standards for an 
NTE zone representing a multiplier times the weighted test result used 
for certification. Because an emission level is an average of various 
points over a test procedure, a multiplier of is inconsistent with the 
idea of a Federal Test Procedure standard as an average. This is 
consistent with the concept of a weighted modal emission test, such as 
the steady-state tests included in this proposal.
    Consistent with the requirements for commercial marine engines, we 
propose that recreational marine diesel engines must meet a cap of 1.5 
times the certified level for HC+NOX, PM, and CO for the 
speed and power subzone below 45 percent of rated power and a cap of 
1.2 times the certified levels at or above 45 percent of rated power. 
However, we are proposing an additional subzone, when compared to the 
commercial NTE zone, at speeds greater than 95 percent of rated. We are 
proposing a cap of 1.5 times the certified levels for this subzone. 
This additional subzone addresses the typical recreational design for 
higher rated power. We understand that this power is needed to ensure 
that the engine can bring the boat to plane.
    We are aware that marine diesel engines may not be able to meet the 
emissions limit under all conditions. Specifically, there are times 
when emission control must be compromised for startability or safety. 
We are not proposing that engine starting be included in the NTE 
testing. In addition, manufacturers would have the option of 
petitioning the Administrator to allow emissions to increase under 
engine protection strategies such as when an engine overheats. This is 
also consistent with the requirements for commercial marine engines.
    e. Ambient conditions. Variations in ambient conditions can affect 
emissions. Such conditions include air temperature, humidity, and 
(especially for aftercooled engines) water temperature. We are 
proposing to apply the commercial marine engine ranges for these 
variables. Chapter 4 of the Draft Regulatory Support Document provides 
more detail on how we determined these ranges. Within the ranges, there 
is no calculation to correct measured emissions to standard conditions. 
Outside of the ranges, emissions can be corrected back to the nearest 
end of the range. The proposed ambient variable ranges are 13 to 
35 deg.C (55 to 95 deg.F) for intake air temperature, 7.1 to 10.7 g 
water/kg dry air (50 to 75 grains/pound dry air) for intake air 
humidity, and 5 to 27 deg.C (41 to 80 deg.F) for ambient water 
temperature.

D. Proposed Testing Requirements

    40 CFR part 94 details specifications for test equipment and 
procedures that apply generally to commercial marine engines. We 
propose to base the recreational marine diesel engine test procedures 
on this part. Section VIII gives a general discussion of the proposed 
testing requirements; this section describes procedures that are 
specific to recreational marine such as the duty cycle for operating 
engines for emission measurements. Chapter 4 of the Draft Technical 
Support Document describes these duty cycles in greater detail.
1. Which Duty Cycles Are Used To Measure Emissions?
    For recreational marine diesel engines, we are proposing to use the 
ISO E5 duty cycle. This is a 5-mode steady state cycle, including an 
idle mode and four modes lying on a cubic propeller curve. ISO intends 
for this cycle to be used for all engines in boats less than 24 meters 
in length. We propose to apply it to all recreational marine diesel 
engines to avoid the complexity of tying emission standards to boat 
characteristics. A given engine may be used in boats longer and shorter 
than 24 meters; engine manufacturers generally will not know the size 
of the boat into which an engine will be installed. Also, we expect 
that most recreational boats will be under 24 meters in length. Chapter 
4 of the Draft Regulatory Support Document provides further detail on 
the ISO E5 duty cycle. We request comment on the appropriateness of 
this duty cycle.
2. What Fuels Will Be Used During Emission Testing?
    We are proposing to use the same specifications for recreational 
marine diesel engines as we have used previously for commercial marine 
diesel engines. That means that the recreational engines will use the 
same test fuel that is required for testing Category 1 commercial 
marine diesel engines, which is a standard nonroad test fuel with 
moderate sulfur content. We are not aware of any difference in fuel 
specifications for recreational and commercial marine engines of 
comparable size.
3. How Would In-Use Testing Be Performed?
    We have the authority to perform in-use testing on marine engines 
to ensure compliance in use. This testing may include taking in-use 
marine engines out of the vessel and testing them in a laboratory, as 
well as field testing of in use engines on the boat, in a marine 
environment. We request comments on the proposed in-use testing 
provisions described below.
    We propose to use field-testing data in two ways. First, we would 
use it as a

[[Page 51142]]

screening tool, with follow-up laboratory testing over the ISO E5 duty 
cycle where appropriate. Second, we would use the data directly as a 
basis for compliance determinations provided that field testing 
equipment and procedures are capable of providing reliable information 
from which conclusions can be drawn regarding what emission levels 
would be in laboratory-based measurements.
    For marine engines that expel exhaust gases underwater or mix their 
exhaust with water, we propose to require manufacturers to equip 
engines with an exhaust sample port where a probe can be inserted for 
in-use exhaust emission testing. It is important that the location of 
this port allow a well-mixed and representative sample of the exhaust. 
The purpose of this proposed provision is to simplify in-use testing.
    One of the advantages of the not-to-exceed requirements will be to 
facilitate in-use testing. This will allow us to perform compliance 
testing in the field. As long as the engine is operating under steady-
state conditions in the NTE zone, we will be able to measure emissions 
and compare them to the NTE limits.

E. Special Compliance Provisions

    The provisions discussed here are designed to minimize regulatory 
burdens on manufacturers needing added flexibility to comply with the 
proposed engine standards. These manufacturers include engine dressers, 
small-volume engine marinizers, and small-volume boat builders.
1. What Are the Proposed Burden Reduction Approaches for Engine 
Dressers?
    Many recreational marine diesel engine manufacturers take a new, 
land-based engine and modify it for installation on a marine vessel. 
Some of the companies that modify an engine for installation on a boat 
make no changes that would affect emissions. Instead, the modifications 
may consist of adding mounting hardware and a generator or reduction 
gears for propulsion. It can also involve installing a new marine 
cooling system that meets original manufacturer specifications and 
duplicates the cooling characteristics of the land-based engine, but 
with a different cooling medium (i.e., water). In many ways, these 
manufacturers are similar to nonroad equipment manufacturers that 
purchase certified land-based nonroad engines to make auxiliary 
engines. This simplified approach of producing an engine can more 
accurately be described as dressing an engine for a particular 
application. Because the modified land-based engines are subsequently 
used on a marine vessel, however, these modified engines will be 
considered marine diesel engines, which then fall under these proposed 
requirements.
    To clarify the responsibilities of engine dressers under this rule, 
we propose to exempt them from the requirement to certify engines to 
the proposed emission standards, as long as they meet the following 
seven proposed conditions.
    (1) The engine being dressed (the ``base'' engine) must be a 
highway, land-based nonroad, or locomotive engine, certified pursuant 
to 40 CFR part 86, 89, or 92, respectively, or a marine diesel engine 
certified pursuant to this part.
    (2) The base engine's emissions, for all pollutants, must be at 
least as good as the otherwise applicable recreational marine emission 
limits. In other words, starting in 2005, a dressed nonroad Tier 1 
engine will not qualify for this exemption, because the more stringent 
standards for recreational marine diesel engines go into effect at that 
time.
    (3) The dressing process must not involve any modifications that 
can change engine emissions. We would not consider changes to the fuel 
system to be engine dressing because this equipment is integral to the 
combustion characteristics of an engine.
    (4) All components added to the engine, including cooling systems, 
must comply with the specifications provided by the engine 
manufacturer.
    (5) The original emissions-related label must remain clearly 
visible on the engine.
    (6) The engine dresser must notify purchasers that the marine 
engine is a dressed highway, nonroad, or locomotive engine and is 
exempt from the requirements of 40 CFR part 94.
    (7) The engine dresser must report annually to us the models that 
are exempt pursuant to this provision and such other information as we 
deem necessary to ensure appropriate use of the exemption.
    We propose that any engine dresser not meeting all these conditions 
be considered an engine manufacturer and would accordingly need to 
certify that new engines comply with this rule's provisions.
    Under this proposal, an engine dresser violating the above criteria 
might be liable under anti-tampering provisions for any change made to 
the land-based engine that affects emissions. The dresser might also be 
subject to a compliance action for selling new marine engines that are 
not certified to the required emission standards.
2. What Was the Small Business Advocacy Review Panel?
    As described in Section XI.B, the August 1999 report of the Small 
Business Advocacy Review Panel addresses the concerns of sterndrive and 
inboard engine marinizers, compression-ignition recreational marine 
engine marinizers, and boat builders that use these engines.
    To identify representatives of small businesses for this process, 
we used the definitions provided by the Small Business Administration 
for engine manufacturers and boat builders. We then contacted companies 
manufacturing internal-combustion engines employing fewer than 1,000 
people to be small-entity representatives for the Panel. Companies 
selling or installing such engines in boats and employing fewer than 
500 people were also considered small businesses for the Panel. Based 
on this information, we asked 16 small businesses to serve as small-
entity representatives. These companies represented a cross-section of 
both gasoline and diesel engine marinizers, as well as boat builders.
    With input from small-entity representatives, the Panel drafted a 
report with findings and recommendations on how to reduce the potential 
small-business burden resulting from this proposed rule. The Panel's 
recommended flexibility options are described in the following 
sections.
3. What Are the Proposed Burden Reduction Approaches for Small-Volume 
Engine Marinizers?
    We are proposing several flexibility options for small-volume 
engine marinizers. The purpose of these options is to reduce the burden 
on companies for which fixed costs cannot be distributed over a large 
number of engines. For this reason, we propose to define a small-volume 
engine manufacturer based on annual U.S. sales of engines. This 
production count would include all engines (automotive, other nonroad, 
etc.) and not just recreational marine engines. We propose to consider 
small businesses to be those that produce fewer than 1000 internal 
combustion engines per year. Based on our characterization of the 
industry, there is a natural break in production volumes above 500 
engine sales where the next smallest manufacturers make tens of 
thousands of engines. We chose 1000 engines as a limit because it 
groups together all the marinizers most needing the proposed burden 
reduction approaches, while still allowing for reasonable sales growth.

[[Page 51143]]

    The proposed flexibility options for small-volume marinizers are 
discussed below and would be used at the manufacturers' discretion. We 
request comment on the appropriateness of these flexibility options or 
other options.
    a. Broaden engine families. We propose to allow small-volume 
marinizers to put all of their models into one engine family (or more 
as necessary) for certification purposes. Marinizers would then certify 
using the ``worst-case'' configuration. This approach is consistent 
with the flexibility offered to post-manufacture marinizers under the 
commercial marine regulations. The advantage of this approach is that 
it minimizes certification testing because the marinizer can certify a 
single engine in the first year to represent their whole product line. 
As for large companies, the small-volume manufacturers would then be 
able carry-over data from year to year until engine design changes 
occur that would significantly affect emissions.
    We understand that this flexibility alone may not be able to reduce 
the burden enough for all small-volume manufactures because it would 
still require a certification test. We consider this to be the foremost 
cost concern for some small-volume manufacturers, because the test 
costs are spread over low sales volumes. Also, we recognize that it may 
be difficult to determine the worst-case emitter without additional 
testing.
    b. Minimize compliance requirements. We propose to waive 
production-line and deterioration testing for small-volume marinizers. 
We would assign a deterioration factor for use in calculating end-of-
life emission factors for certification. The advantages of this 
approach would be to minimize compliance testing. Production-line and 
deterioration testing would be more extensive than a single 
certification test.
    There are also some disadvantages of this approach, because there 
would be no testing assurance of engine emissions at the production 
line. This is especially a concern without a manufacturer-run in-use 
testing program. Also, assigned deterioration factors would not be as 
accurate as deterioration factors determined by the manufacturer 
through testing. We request comment on appropriate deterioration 
factors for the technology discussed in this proposal.
    c. Expand engine dresser flexibility. We propose to expand the 
engine dresser definition for small-volume marinizers to include water-
cooled turbochargers where the goal is to match the performance of the 
non water-cooled turbocharger on the original certified configuration. 
We believe this would provide more opportunities for diesel marinizers 
to be excluded from certification testing if they operate as dressers.
    There would be some potential for adverse emissions impacts because 
emissions are sensitive to turbo-matching; however, if the goal of the 
marinizer is to match the performance of the original turbocharger, 
this risk should be small. We recognize that this option would not 
likely benefit all diesel marinizers because changes to fuel management 
for power would not qualify under engine dressing.
    d. Streamlined certification. We are requesting comment on allowing 
small-volume marinizers to certify to a performance standard by showing 
their engines meet design criteria rather than by certification 
testing. The goal would be to reduce the costs of certification 
testing. We are concerned that this approach must be implemented 
carefully to work effectively. This would put us in the undesirable 
position of specifying engine designs for marinizers, which we have 
historically avoided by setting performance standards.
    We are not clear on how to set meaningful design criteria for 
marine diesel engines. We expect that emission reductions in diesel 
engines will be achieved through careful calibration of the engine fuel 
and air management systems using strategies such as timing retard and 
charge-air cooling. It may not be feasible to specify criteria for 
ignition timing, charge-air temperatures, and injection pressures that 
would ensure that every engine can achieve the targeted level of 
emission control. While we do not believe design criteria can be set to 
provide sufficient assurance of emission control from these engines, we 
ask for comment on any possible approaches.
    We propose to allow small-volume marinizers to certify to the 
proposed not-to-exceed (NTE) requirements with a streamlined approach. 
We believe small-volume marinizers could make a satisfactory showing 
that they meet NTE standards with limited test data. Once these 
manufacturers test engines over the proposed five-mode certification 
duty cycle (E5), they could use those or other test points to 
extrapolate the results to the rest of the NTE zone. For example, an 
engineering analysis could consider engine timing and fueling rate to 
determine how much the engine's emissions may change at points not 
included in the E5 cycle. For this streamlined NTE approach, we propose 
that keeping all four test modes of the E5 cycle within the NTE 
standards would be enough for small-volume marinizers to certify 
compliance with NTE requirements, as long as there are no significant 
changes in timing or fueling rate between modes. We request comment on 
this approach.
    e. Delay standards for five years. We propose that small-volume 
marinizers not have to comply with the standards for five years after 
they take effect for larger companies. Under this plan the proposed 
standards would take effect from 2011 to 2014 for small-volume 
marinizers, depending on engine size. We propose that marinizers would 
be able to apply this delay to all or just a portion of their 
production. They could therefore still sell engines that meet the 
standards when possible on some product lines while delaying 
introduction of emission-control technology on other product lines. 
This option provides more time for small marinizers to redesign their 
products, allowing time to learn from the technology development of the 
rest of the industry.
    While we are concerned about the loss of emission control from part 
of the fleet during this time, we recognize the special needs of small-
volume marinizers and believe the added time may be necessary for these 
companies to comply with the proposed emission standards. This 
additional time will allow small-volume marinizers to obtain and 
implement proven, cost-effective emission-control technology. Some 
small-volume marinizers have expressed concern to the Small Business 
Advocacy Panel that large manufacturers could have competitive 
advantage if they market their engines as cleaner than the small-
business engines. Other small-volume manufacturers commented that this 
provision would be useful to them.
    We are also requesting comment on limited exemptions for small-
volume marinizers. Under this sort of flexibility, upon request from a 
small-volume marinizer, we would exempt a small number of engines per 
year for 8 to 10 years. An example of a small-volume exemptions would 
be 50 marine diesel engines per year. We are concerned, however, that 
this approach may not be appropriate given our goal of reducing burden 
on small businesses without significant loss in emission control.
    f. Hardship provisions. We are proposing two hardship provisions 
for small-volume marinizers. Marinizers would be able to apply for this 
relief on an annual basis. First, we propose that small marinizers 
could petition us for additional time to comply with the standards. The 
marinizer would have to make the case that it has taken all

[[Page 51144]]

possible steps to comply but the burden of compliance costs would have 
a major impact on the company's solvency. Also, if a certified base 
engine were available, we propose that the marinizer would have to use 
this engine. We believe this provision would protect small-volume 
marinizers from undue hardship due to certification burden. Also, some 
emission reduction could be gained if a certified base engine becomes 
available.
    Second, we propose that small-volume marinizers could also apply 
for hardship relief if circumstances outside their control caused the 
failure to comply (such as a supply contract broken by parts supplier) 
and if failure to sell the subject engines would have a major impact on 
the company's solvency. We would consider this relief mechanism as a 
option to be used only as a last resort. We believe this provision 
would protect small-volume marinizers from circumstances outside their 
control.
    g. Use of emission credits. We request comment on the 
appropriateness of allowing small-volume manufacturers to purchase 
credits under the streamlined certification approach described above. 
Under this approach, the engine's emission performance for purposes of 
certification is determined on the basis of design features rather than 
emission test results alone. Certification would therefore depend on 
engineering analysis and design criteria. Without a full set of 
emission test data, however, it would not be possible for these 
manufacturers to participate in an emission-credit program.
    We believe the level of credits necessary to offset emissions from 
uncontrolled engines could be established conservatively to maximize 
assurance of compliance. For this reason, the baseline emissions of the 
uncontrolled engine could be based on the worst-case baseline data we 
are aware of, which would currently be 20 g/kW-hr HC+NOX and 
1 g/kW-hr PM. The credits needed would then be calculated using the 
proposed standards and the usage assumptions presented in Chapter 6 of 
the Draft Regulatory Support Document.
    Under this limited emission-credit program, we propose that the 
participating manufacturer would be able to buy credits offered for 
sale by recreational marine diesel engine manufacturers certifying only 
on the basis of emission tests (not using the streamlined certification 
described above). We propose that cross-trading outside of recreational 
marine not be allowed, because it could prevent emission reductions 
from being achieved in areas where boats contribute most significantly 
to local air pollution and it could prevent new technology from being 
applied to recreational marine engines. However, we request comment on 
whether or not small-volume marinizers should be able to use credits 
generated from other sectors such as land-based nonroad engines.
4. What Are the Proposed Burden Reduction Approaches for Small-Volume 
Boat Builders Using Recreational Marine Diesel Engines?
    The SBAR Panel Report recommends that we propose burden reduction 
approaches for small-volume boat builders. This recommendation was 
based on the concern that, although boat builders would not be directly 
regulated under the proposed engine standards, they may need to 
redesign engine compartments on some boats if engine designs were to 
change significantly. Based on comments from industry, we believe these 
flexibility options may be appropriate; however, they may also turn out 
to be unnecessary.
    We are proposing four flexibility options for small-volume vessel 
manufacturers using recreational marine diesel engines. The purpose of 
these options is to reduce the burden on companies for which fixed 
costs cannot be distributed over a large number of vessels. For this 
reason, we propose to define a small-volume boat builder as one that 
produces fewer than 100 boats for sale in the U.S. in one year and 
meets the Small Business Administration definition of a small business 
(fewer than 500 employees). The production count would include all 
engine-powered recreational boats. We propose that these flexibility 
options be used at the manufacturer's discretion. The proposed 
flexibility options for small-volume boat builders are discussed below. 
We request comment on the appropriateness of these or other flexibility 
options.
    a. Percent-of-production delay. This proposed flexibility would 
allow manufacturers, with written request from a small-volume boat 
builder and prior approval from us, to produce a limited number of 
uncertified recreational marine engines. We propose that, over a period 
of five years (2006-2010), small-volume boat builders would be able to 
purchase uncertified engines to sell in boats for an amount equal to 80 
percent of engine sales for one year. For example, if the small boat 
builder sells 100 engines per year, a total of 80 uncertified engines 
may be sold over the five-year period. This should give small boat 
builders flexibility to delay using new engine designs for a portion of 
business.
    We currently believe this flexibility is appropriate, however, it 
is possible that this flexibility could turn out to be unnecessary if 
the standards do not result in significant changes in engine size, 
power-to-weight ratio, or other parameters that would affect boat 
design. Moreover, custom boat builders may not need this flexibility if 
they design each boat from the ground up. We are also concerned that 
this flexibility could reduce the market for the certified engines 
produced by the engine manufacturers and could make it difficult for 
customs inspectors to know which uncertified engines can be imported. 
We therefore propose that engines produced under this flexibility would 
have to be labeled as such.
    b. Small-volume allowance. This proposed flexibility is similar to 
the percent-of-production allowance, but is designed for boat builders 
with very small production volumes. The only difference with the above 
flexibility would be that the 80-percent allowance described above 
could be exceeded as long as sales do not exceed either 10 engines per 
year or 20 engines over five years (2006-2010). This proposed 
flexibility would apply only to engines less than or equal to 2.5 
liters per cylinder.
    c. Existing inventory and replacement engine allowance. We propose 
that small-volume boat builders be allowed to sell their existing 
inventory after the implementation date of the new standards. However, 
no purposeful stockpiling of uncertified engines would be permitted. 
This provision is intended to allow small boat builders flexibility to 
turn over engine designs.
    d. Hardship relief provision. We propose that small boat builders 
could apply for hardship relief if circumstances outside their control 
caused the problem (for example, if a supply contract were broken by 
the engine supplier) and if failure to sell the subject vessels would 
have a major impact on the company's solvency. This relief would allow 
the boat builder to use an uncertified engine and would be considered a 
mechanism of last resort. These hardship provisions are consistent with 
those currently in place for post-manufacture marinizers of commercial 
marine diesel engines.

F. Technical Amendments

    The proposed regulations include a variety of amendments to the 
programs already adopted for marine spark-ignition and diesel engines, 
as described in the following paragraphs.

[[Page 51145]]

1. 40 CFR Part 91
    We have identified three principal amendments to the requirements 
for outboard and personal watercraft engines. First, we are proposing 
to add a definition of United States. This is especially helpful in 
clearing up questions related to U.S. territories in the Carribean Sea 
and the Pacific Ocean. Second, we have found two typographical errors 
in the equations needed for calculating emission levels in 40 CFR 
91.419. Finally, we are proposing to clarify testing rates for the in-
use testing program. The regulations currently specify a maximum rate 
of 25 percent of a manufacturer's engine families. We are proposing to 
clarify that for manufacturers with fewer than four engine families, 
the maximum testing rate should be one family per year in place of the 
percentage calculation. We request comment on these amendments. 
Specifically, we request comment on whether there is a need to delay 
the effectiveness of any of these amendments to allow manufacturers 
time to comply with new requirements.
2. 40 CFR Part 94
    We are proposing several regulatory amendments to the program for 
commercial marine diesel engines. Several of these are straightforward 
edits for correct grammar and cross references.
    We propose to change the definition of United States, as described 
in the previous section.
    We are proposing to add a definition for spark-ignition, consistent 
with the existing definition for compression-ignition. This would allow 
us to define compression-ignition as any engine that is not spark-
ignition. This would help ensure that marine emission standards for the 
different types of engines fit together appropriately. We do not expect 
this change to affect any current engines.
    The discussion of production-line testing in Section III includes a 
proposal to reduce testing rates after two years of consistent good 
performance. We propose to extend this provision to commercial marine 
diesel engines as well.
    The test procedures for Category 2 marine engines give a cross-
reference to 40 CFR part 92, which defines the procedures for testing 
locomotives and locomotive engines. Part 92 specifies a wide range of 
ambient temperatures for testing, to allow for outdoor measurements. We 
expect all testing of Category 2 marine engines to occur indoors and 
are therefore proposing to adopt a range of 13 deg. to 30 deg. C 
(55 deg. to 86 deg. F) for emission testing.
    We request comment on modifying the language prohibiting emission 
controls that increase unregulated pollutants. The existing language 
states:

    An engine with an emission-control system may not emit any 
noxious or toxic substance which would not be emitted in the 
operation of the engine in the absence of such a system, except as 
specifically permitted by regulation.

Amended regulatory language would focus on preventing emissions that 
would endanger public welfare, rather than setting a standard that 
allows no tradeoff between pollutants. We are considering this also in 
emission-control programs for other types of engines, since various 
prospective engine technologies require more careful consideration of 
this issue.

    You may not design your engines with emission-control devices, 
systems, or elements of design that cause or contribute to an 
unreasonable risk to public health, welfare, or safety while 
operating. This applies especially if the engine emits any noxious 
or toxic substance it would otherwise not emit.

    After completing the final rule for commercial marine diesel 
engines, manufacturers expressed a concern about the phase-in schedule 
for engine models under 2.5 liters per cylinder. Some of these engine 
models include ratings above 560 kW (750 hp). When we proposed emission 
standards for these engines, we suggested that the larger engines could 
certify according to an earlier schedule, since the lower-power engines 
from those product lines would need to meet emission standards for 
marine and land-based nonroad engines earlier. We received no comment 
on this position. We request comment on the need to accommodate 
manufacturers' calibration, certification, and production schedules in 
aligning the marine and land-based nonroad diesel engine emission 
standards and on what offsets are appropriate.

G. Technological Feasibility

    We believe the emission-reduction strategies expected for land-
based nonroad diesel engines and commercial marine diesel engines can 
also be applied to recreational marine diesel engines. Marine diesel 
engines are generally derivatives of land-based nonroad and highway 
diesel engines. Marine engine manufacturers and marinizers make 
modifications to the engine to make it ready for use in a vessel. These 
modifications can range from basic engine mounting and cooling changes 
to a restructuring of the power assembly and fuel management system. 
Chapters 3 and 4 of the Draft Regulatory Support Document discuss this 
process in more detail. Also, we have collected emission data 
demonstrating the feasibility of the not-to-exceed requirements. These 
data are presented in Chapter 4 of the Draft Regulatory Support 
Document.
1. Implementation Schedule
    For recreational marine diesel engines, the proposed implementation 
schedule allows an additional two years of delay beyond the commercial 
marine diesel standards. This represents up to a five-year delay in 
standards relative to the implementation dates of the land-based 
nonroad standards. This should reduce the burden of complying with the 
proposed regulatory scheme by allowing time for carryover of technology 
from land-based nonroad and commercial marine diesel engines. In 
addition, the proposed implementation dates represent four or more 
years of lead time beyond the planned date for our final rule.
2. Standard Levels
    Marine diesel engines are typically derived from or use the same 
technology as land-based nonroad and commercial marine diesel engines 
and should therefore be able to effectively use the same emission-
control strategies. In fact, recreational marine engines can make more 
use of the water they operate in as a cooling medium compared with 
commercial marine, because they are able to make use of raw-water 
aftercooling. This can help them reduce charge-air intake temperatures 
more easily than the commercial models and much more easily than land-
based nonroad diesel engines. Cooling the intake charge reduces the 
formation of NOX emissions.
3. Technological Approaches
    We anticipate that manufacturers will meet the proposed standards 
for recreational marine diesel engines primarily with technology that 
will be applied to land-based nonroad and commercial marine diesel 
engines. Much of this technology has already been established in 
highway applications and is being used in limited land-based nonroad 
and marine applications. Our analysis of this technology is described 
in detail in Chapters 3 and 4 of the Draft Regulatory Support Document 
for this proposed rule and is summarized here. We request comment on 
the applicability of the technology discussed below for CI recreational 
marine engines.
    Our cost analysis is based on the technology package which we 
believe

[[Page 51146]]

most manufacturers will apply and is described in Chapter 5 of the 
Draft Regulatory Support Document. Our estimated costs of control are 
an ``average'' based on this technology package. This assumes that 
reductions from the package are all necessary and that the performance 
in the area of emission reductions is linear. While we believe this is 
a reasonable approach for estimating the overall costs of compliance, 
we are also seeking comment on whether there are different technologies 
or different application of the technologies in our package which could 
affect the marginal costs of compliance. That is to say, is there an 
incremental difference in technology which would reduce (or increase) 
costs significantly, and thus significantly affect the costs of control 
for a small given margin of additional emission reduction.
    By proposing standards that don't go into place until 2006, we are 
providing engine manufacturers with substantial lead time for 
developing, testing, and implementing emission-control technologies. 
This lead time and the coordination of standards with those for land-
based nonroad engines allows time for a comprehensive program to 
integrate the most effective emission-control approaches into the 
manufacturers' overall design goals related to durability, reliability, 
and fuel consumption.
    Engine manufacturers have already shown some initiative in 
producing limited numbers of low-NOX marine diesel engines. 
More than 80 of these engines have been placed into service in 
California through demonstration programs. The Draft Regulatory Support 
Document further discusses these engines and their emission results. 
Through the demonstration programs, we were able to gain some insight 
into what technologies can be used to meet the proposed emission 
standards.
    Highway engines have been the leaders in developing new emission-
control technology for diesel engines. Because of the similar engine 
designs in land-based nonroad and marine diesel engines, it is clear 
that much of the technological development that has led to lower-
emitting highway engines can be transferred or adapted for use on land-
based nonroad and marine engines. Much of the improvement in emissions 
from these engines comes from ``internal'' engine changes such as 
variation in fuel-injection variables (injection timing, injection 
pressure, spray pattern, rate shaping), modified piston bowl geometry 
for better air-fuel mixing, and improvements intended to reduce oil 
consumption. Introduction and ongoing improvement of electronic 
controls have played a vital role in facilitating many of these 
improvements.
    Turbocharging is widely used now in marine applications, especially 
in larger engines, because it improves power and efficiency by 
compressing the intake air. Turbocharging may also be used to decrease 
particulate emissions in the exhaust. Today, marine engine 
manufacturers generally have to rematch the turbocharger to the engine 
characteristics of the marine version of a nonroad engine and often 
will add water jacketing around the turbocharger housing to keep 
surface temperatures low. Once the nonroad Tier 2 engines are available 
to the marine industry, matching the turbochargers for the engines will 
be an important step in achieving low emissions.
    Aftercooling is a well established technology for reducing 
NOX by decreasing the temperature of the charge air after it 
has been heated during compression. Decreasing the charge-air 
temperature directly reduces the peak cylinder temperature during 
combustion, which is the primary cause of NOX formation. 
Air-to-water and water-to-water aftercoolers are well established for 
land-based applications. For engines in marine vessels, there are two 
different types of aftercooling: jacket-water and raw-water 
aftercooling. With jacket-water aftercooling, the fluid that extracts 
heat from the aftercooler is itself cooled by ambient water. This 
cooling circuit may either be the same circuit used to cool the engine 
or it may be a separate circuit. By moving to a separate circuit, 
marine engine manufacturers would be able to achieve further reductions 
in the charge-air temperature. This separate circuit could result in 
even lower temperatures by using raw water as the coolant. This means 
that ambient water is pumped directly to the aftercooler. Raw-water 
aftercooling is currently widely used in recreational applications. 
Because of the access that marine engines have to a large ambient water 
cooling medium, we anticipate that marine diesel engine manufacturers 
will largely achieve the reductions in NOX emissions for 
this proposal through the use of aftercooling.
    Electronic controls also offer great potential for improved control 
of engine parameters for better performance and lower emissions. Unit 
pumps or injectors would allow higher-pressure fuel injection with rate 
shaping to carefully time the delivery of the whole volume of injected 
fuel into the cylinder. Marine engine manufacturers should be able to 
take advantage of modifications to the routing of the intake air and 
the shape of the combustion chamber of nonroad engines for improved 
mixing of the fuel-air charge. Separate-circuit aftercooling (both 
jacket-water and raw-water) will likely gain widespread use in 
turbocharged engines to increase performance and lower NOX.
4. Our Conclusions
    The proposed standards for recreational marine diesel engines 
reasonably reflect what manufacturers can achieve through the 
application of available technology. Recreational marine diesel engine 
manufacturers will need to use the available lead time to develop the 
necessary emission-control strategies, including transfer of technology 
from land-based nonroad and commercial marine CI engines. This 
development effort will require not only achieving the targeted 
emission levels, but also ensuring that each engine will meet all 
performance and emission requirements over its useful life. The 
proposed standards clearly represent significant reductions compared 
with baseline emission levels.
    Emission-control technology for diesel engines is in a period of 
rapid development in response to the range of emission standards in 
place (and under consideration) for highway and land-based nonroad 
engines in the years ahead. This development effort will automatically 
transfer to some extent to marine engines, because marine engines are 
often derivatives of highway and land-based nonroad engines. 
Regardless, this development effort would need to expand to meet the 
proposed standards. Because the technology development for highway and 
land-based nonroad engines will largely constitute basic research of 
diesel engine combustion, the results should generally find direct 
application to marine engines.
    Based on information currently available, we believe it is feasible 
for recreational marine diesel engine manufacturers to meet the 
proposed standards using combinations of technological approaches 
discussed above and in Chapters 3 and 4 of the Draft Regulatory Support 
Document. To the extent that the technologies described above may not 
yield the full degree of emission reduction anticipated, manufacturers 
could still rely on a modest degree of fuel-injection timing retard as 
a strategy for complying with the proposed emission standards.
    In addition, we believe the flexibilities incorporated into this 
proposal will permit marinizers and boat builders to respond to engine 
changes in an orderly way. We expect that meeting these requirements 
will

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