[Federal Register: May 6, 2008 (Volume 73, Number 88)]
[Rules and Regulations]
[Page 25097-25352]
[DOCID:fr06my08-15]

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Part II

Environmental Protection Agency

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40 CFR Parts 9, 85, et al.

 Control of Emissions of Air Pollution From Locomotive Engines and
Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder;
Final Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9, 85, 86, 89, 92, 94, 1033, 1039, 1042, 1065, and
1068

[EPA-HQ-OAR-2003-0190; FRL-8545-3]
RIN 2060-AM06

Control of Emissions of Air Pollution From Locomotive Engines and
Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is adopting a comprehensive program to dramatically reduce
pollution from locomotives and marine diesel engines. The controls will
apply to all types of locomotives, including line-haul, switch, and
passenger, and all types of marine diesel engines below 30 liters per
cylinder displacement, including commercial and recreational,
propulsion and auxiliary. The near-term emission standards for newly-
built engines will phase in starting in 2009. The near-term program
also includes new emission limits for existing locomotives and marine
diesel engines that apply when they are remanufactured, and take effect
as soon as certified remanufacture systems are available, as early as
2008. The long-term emissions standards for newly-built locomotives and
marine diesel engines are based on the application of high-efficiency
catalytic aftertreatment technology. These standards begin to take
effect in 2015 for locomotives and in 2014 for marine diesel engines.
We estimate particulate matter (PM) reductions of 90 percent and
nitrogen oxides (NOX>) reductions of 80 percent from engines
meeting these standards, compared to engines meeting the current
standards.
    We project that by 2030, this program will reduce annual emissions
of NOX> and PM by 800,000 and 27,000 tons, respectively. EPA
projects these reductions will annually prevent up to 1,100 PM-related
premature deaths, 280 ozone-related premature deaths, 120,000 lost work
days, 120,000 school day absences, and 1.1 million minor restricted-
activity days. The annual monetized health benefits of this rule in
2030 will range from $9.2 billion to $11 billion, assuming a 3 percent
discount rate, or between $8.4 billion to $10 billion, assuming a 7%
discount rate. The estimated annual social cost of the program in 2030
is projected to be $740 million, significantly less than the estimated
benefits.

DATES: This rule is effective on July 7, 2008. The incorporation by
reference of certain publications listed in this regulation is approved
by the Director of the Federal Register as of July 7, 2008.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-2003-0190. All documents in the docket are listed on the
www.regulations.gov> web site. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available either electronically through
www.regulations.gov> or in hard copy at the Air Docket, EPA/DC, EPA
West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. The
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the Air
Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: John Mueller, U.S. EPA, Office of
Transportation and Air Quality, Assessment and Standards Division
(ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann
Arbor, MI 48105; telephone number:<PHONE_NUMBER>; fax number: (734)
214-4816; e-mail address: Mueller.John@epa.gov,> or Assessment and
Standards Division Hotline; telephone number:<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Does This Action Apply to Me?

 Locomotives

    Entities potentially affected by this action are those that
manufacture, remanufacture or import locomotives or locomotive engines;
and those that own or operate locomotives. Regulated categories and
entities include:

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                                              Examples of potentially
       Category           NAICS code \1\         affected entities
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Industry..............     333618, 336510  Manufacturers,
                                            remanufacturers and
                                            importers of locomotives and
                                            locomotive engines.
Industry..............    482110, 482111,  Railroad owners and
                                   482112   operators.
Industry..............             488210  Engine repair and
                                            maintenance.
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    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in the table could also be regulated. To determine whether
your company is regulated by this action, you should carefully examine
the applicability criteria in 40 CFR 92.1, 1033.1, 1065.1, and 1068.1.
If you have questions, consult the person listed in the preceding FOR
FURTHER INFORMATION CONTACT> section.
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    \1\ North American Industry Classification System (NAICS).
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 Marine Engines and Vessels

    Entities potentially affected by this action are companies and
persons that manufacture, sell, or import into the United States new
marine compression-ignition engines, companies and persons that rebuild
or maintain these engines, companies and persons that make vessels that
use such engines, and the owners/operators of such vessels. Affected
categories and entities include:

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                                              Examples of potentially
       Category           NAICS code \1\         affected entities
------------------------------------------------------------------------
Industry..............             333618  Manufacturers of new marine
                                            diesel engines.
Industry..............   33661 and 346611  Ship and boat building; ship
                                            building and repairing.

Industry..............             811310  Engine repair, remanufacture,
                                            and maintenance.
Industry..............                483  Water transportation, freight
                                            and passenger.
Industry..............             487210  and Sightseeing
                                            Transportation, Water.
Industry..............               4883  Support Activities for Water
                                            Transportation.
Industry..............               1141  Fishing.
Industry..............             336612  Boat building (watercraft not
                                            built in shipyards and
                                            typically of the type
                                            suitable or intended for
                                            personal use).
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in the table could also be regulated. To determine whether
your company is regulated by this action, you should carefully examine
the applicability criteria in 40 CFR 94.1, 1042.1, 1065.1, and 1068.1.
If you have questions, consult the person listed in the preceding FOR
FURTHER INFORMATION CONTACT> section.

Outline of This Preamble

I. Overview
    A. What Is EPA Finalizing and How Does It Differ From the
Proposal?
    B. Why Is EPA Taking This Action?
II. Air Quality and Health Impacts
    A. Overview
    B. Public Health Impacts
    C. Environmental Impacts
    D. Other Criteria Pollutants Affected by This Final Rule
    E. Emissions from Locomotive and Marine Diesel Engines
III. Emission Standards
    A. What Locomotives and Marine Engines Are Covered?
    B. What Standards Are We Adopting?
    C. Are the Standards Feasible?
IV. Certification and Compliance Program
    A. Issues Common to Locomotives and Marine Engines
    B. Compliance Issues Specific to Locomotives
    C. Compliance Issues Specific to Marine Engines
V. Costs and Economic Impacts
    A. Engineering Costs
    B. Cost Effectiveness
    C. EIA
VI. Benefits
VII. Alternative Program Options
    A. Summary of Alternatives
    B. Summary of Results
VIII. Public Participation
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132 (Federalism)
    F. Executive Order 13175 (Consultation and Coordination With
Indian Tribal Governments)
    G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act
X. Statutory Provisions and Legal Authority

I. Overview

    This final rule completes an important step in EPA's ongoing
National Clean Diesel Campaign (NCDC) by adding new programs for
locomotives and marine diesel engines to the clean diesel initiatives
we have already undertaken for highway, other nonroad, and stationary
diesel engines. As detailed below, it significantly strengthens the
locomotive and marine diesel programs we proposed last year (72 FR
15938, April 3, 2007), especially in controlling emissions during the
critical early years through the early introduction of advanced
technologies and the more complete coverage of existing engines. When
fully implemented, this coordinated set of new programs will reduce
harmful diesel engine emissions to a small fraction of their previous
levels.
    The new programs address all types of diesel locomotives-- line-
haul, switch, and passenger rail, and all types of marine diesel
engines below 30 liters per cylinder displacement (hereafter referred
to as ``marine diesel engines'').\2\ These engines are used to power a
wide variety of vessels, from small fishing and recreational boats to
large tugs and Great Lakes freighters. They are also used to generate
auxiliary vessel power, including on ocean-going ships.
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    \2\ Marine diesel engines at or above 30 liters per cylinder,
called Category 3 engines, are typically used for propulsion power
on ocean-going ships. EPA is addressing Category 3 engines through
separate actions, including a planned rulemaking for a new tier of
federal standards (see Advance Notice of Proposed Rulemaking
published December 7, 2007 at 72 FR 69522) and participation on the
U.S. delegation to the International Maritime Organization for
negotiations of new international standards (see http://www.epa.gov/
otaq/oceanvessels.com> for information on both of those actions), as
well as EPA's Clean Ports USA Initiative (see http://www.epa.gov/
cleandiesel/ports/index.htm>).
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    Emissions of fine particulate matter (PM2.5>) and
nitrogen oxides (NOX>) from these diesel engines contribute
to nonattainment of the National Ambient Air Quality Standards (NAAQS)
for PM2.5> and ozone. Today, locomotives and marine diesel
engines account for about 20 percent of mobile source NOX>
emissions and 25 percent of mobile source diesel PM2.5>
emissions in the U.S. Absent this final action, by 2030 the relative
contributions of NOX> and PM2.5> from these
engines would have grown to 35 and 65 percent, respectively.
    We are finalizing a comprehensive three-part program to address
this problem. First, we are adopting stringent emission standards for
existing locomotives and for existing commercial marine diesel engines
above 600 kilowatt (kW) (800 horsepower (hp)). These standards apply
when the engines are remanufactured. This part of the program will take
effect as soon as certified remanufacture systems are available, for
some engines as early as a few months from now. Under our existing
program, locomotives have been certified to one of three tiers of
standards: Tier 0 for locomotives originally built between 1973 and
2001, Tier 1 for those built between 2002 and 2004, and Tier 2 for
those built in or after 2005. Under this new program, certified
locomotive remanufacture systems must be made available by 2010 for
Tier 0 and Tier 1 locomotives, and by 2013 for Tier 2 locomotives.
Remanufacture systems that are certified for use in marine engine
remanufactures are likewise required to be used. We are not, however,
setting a specific compliance date for certified marine diesel
remanufacture systems because we expect that engine manufacturers will
be well motivated by the market opportunity to certify emissions-
compliant systems.
    Second, we are adopting a set of near-term emission standards,
referred to as Tier 3, for newly-built locomotives and marine engines.
The Tier 3 standards reflect the application of technologies to reduce
engine-out particulate matter (PM) and NOX>.
    Third, we are adopting longer-term standards, referred to as Tier
4, for newly-built locomotives and marine

engines. Tier 4 standards reflect the application of high-efficiency
catalytic aftertreatment technology enabled by the availability of
ultra-low sulfur diesel fuel (ULSD). These standards take effect in
2015 for locomotives, and phase in over time for marine engines,
beginning in 2014. Finally, we are adopting provisions in all three
parts of the program to eliminate emissions from unnecessary locomotive
idling.
    Locomotives and marine diesel engines designed to these Tier 4
standards will achieve PM reductions of 90 percent and NOX>
reductions of 80 percent, compared to engines meeting the current Tier
2 standards. The new standards will also yield sizeable reductions in
emissions of nonmethane hydrocarbons (NMHC), carbon monoxide (CO), and
hazardous compounds known as air toxics. Table I-1 summarizes the PM
and NOX> emission reductions for the new standards compared
to today's (Tier 2) emission standards; for remanufactured engines, the
comparison is to the current standards for each tier of locomotives
covered, and to typical unregulated levels for marine engines.

                            Table I-1.--Reductions From Levels of Existing Standards
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                                                                                PM
                 Sector                            Standards tier           (percent)        NOX> (percent)
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Locomotives.............................  Remanufactured Tier 0..........           60  15-20.
                                          Remanufactured Tier 1..........           50  ........................
                                          Remanufactured Tier 2..........           50  ........................
                                          Tier 3.........................           50  ........................
                                          Tier 4.........................           90  80.
                                          All tiers--idle emissions......           50  50.
Marine Diesel Engines \a\...............  Remanufactured Engines.........        25-60  Up to 20.
                                          Tier 3.........................           50  20.
                                          Tier 4.........................           90  80.
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Note:> (a) Standards vary by displacement and within power categories. Reductions indicated are typical.

    On a nationwide annual basis, these reductions will amount to
800,000 tons of NOX> and 27,000 tons of PM by 2030,
resulting annually in the prevention of up to 1,100 PM-related
premature deaths, 280 ozone-related premature deaths, 120,000 lost work
days, 120,000 school day absences, and 1.1 million minor restricted-
activity days. We estimate the annual monetized health benefits of this
rule in 2030 will range from $9.2 billion to $11 billion, assuming a 3
percent discount rate, or between $8.4 billion to $10 billion, assuming
a 7% discount rate.\3\ The estimated annual social cost of the program
in 2030 is projected to be $740 million, significantly less than the
estimated benefits.
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    \3\ Low and high benefits estimates are derived from a range of
ozone-related premature mortality studies (including an assumption
of no causality) and PM2.5-related premature mortality
based on the ACS study (Pope et al., 2002). Benefits also include
PM2.5- and ozone-related morbidity benefits. See section
VI for a complete discussion and analysis of benefits associated
with the final rule.
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A. What Is EPA Finalizing and How Does it Differ From the Proposal?

    This final rule makes a number of important changes to the program
set out in our Notice of Proposed Rulemaking (NPRM). Among these are
changes that will yield significantly greater overall NOX
and PM reductions, especially in the critical early years of the
program: The adoption of standards for remanufactured marine engines
and a 2-year pull-ahead of the Tier 4 NOX requirements for
line-haul locomotives and for 2000-3700 kW (2760-4900 hp) marine
engines.
    The major elements of the final program are summarized below. We
are also revising existing testing, certification, and compliance
provisions to better ensure emissions control in use. Detailed
provisions and our justifications for them are discussed in sections
III and IV. Section VII of this preamble describes a number of
alternatives that we considered in developing the rule. After
evaluating the alternatives, we believe that our new program provides
the best opportunity for achieving timely and very substantial
emissions reductions from locomotive and marine diesel engines. It
balances a number of key factors: (1) Achieving very significant
emissions reductions as early as possible, (2) providing appropriate
lead time to develop and apply advanced control technologies, and (3)
coordinating requirements in this final rule with existing highway and
nonroad diesel engine programs. The provisions we are finalizing that
are different from the proposed program are:
     The adoption of standards for remanufactured marine diesel
engines to address emissions from the existing fleet (this was
presented as one of the proposal alternatives),
     Inclusion of Tier 4 NOX controls on 2015-2016
model year locomotives at initial build rather than at first
remanufacture,
     A two-year pull-ahead of the Tier 4 NOX
standard for 2000-3700 kW marine engines to 2014,
     Inclusion of Class II railroads in the remanufactured
locomotives program,
     No Tier 4 standards for the small fleet of large
recreational vessels at this time,
     A revised approach to migratory vessels that spend part of
their time overseas,
     Credit for locomotive design measures that reduce
emissions as part of efforts to improve efficiency,
     A number of changes to test and compliance requirements
detailed in sections III and IV.
    Overall, our comprehensive three-part approach to setting standards
for locomotives and marine diesel engines will provide very large
reductions in PM, NOX, and toxic compounds, both in the
near-term (as early as 2008), and in the long-term. These reductions
will be achieved in a manner that: (1) Leverages technology
developments in other diesel sectors, (2) aligns well with the clean
diesel fuel requirements already being implemented, and (3) provides
the lead time needed to deal with the significant engineering design
workload that is involved.
(1) Locomotive Emission Standards
    We are setting stringent exhaust emission standards for newly-built
and remanufactured locomotives, furthering the initiative for cleaner
locomotives started in 2004 with the establishment of the ULSD
locomotive fuel program, and adding this important category of engines
to the highway and nonroad diesel applications already covered

under EPA's National Clean Diesel Campaign.
    Briefly, for newly-built line-haul locomotives we are setting a new
Tier 3 PM standard of 0.10 grams per brake horsepower-hour (g/bhp-hr),
based on improvements to existing engine designs. This standard will
take effect in 2012. We are also setting new Tier 4 standards of 0.03
g/bhp-hr for PM and 1.3 g/bhp-hr for NOX, based on the
evolution of high-efficiency catalytic aftertreatment technologies now
being developed and introduced in the highway diesel sector. The Tier 4
standards will take effect in 2015. We are requiring that
remanufactured Tier 2 locomotives meet a PM standard of 0.10 g/bhp-hr,
based on the same engine design improvements as Tier 3 locomotives, and
that remanufactured Tier 0 and Tier 1 locomotives meet a 0.22 g/bhp-hr
PM standard. We are also requiring that remanufactured Tier 0
locomotives meet a NOX standard of 7.4 g/bhp-hr, the same
level as current Tier 1 locomotives, or 8.0 g/bhp-hr if the locomotive
is not equipped with a separate loop intake air cooling system. Section
III provides a detailed discussion of these new standards, and section
IV details improvements being made to the applicable test,
certification, and compliance programs.
    In setting our original locomotive emission standards in 1998, the
historic pattern of transitioning older line-haul locomotives to road-
and yard-switcher service resulted in our making little distinction
between line-haul and switch locomotives. Because of the increase in
the size of new locomotives in recent years, that pattern cannot be
sustained by the railroad industry, as today's 4000+ hp (3000+ kW)
locomotives are poorly suited for switcher duty. Furthermore, although
there is still a fairly sizeable legacy fleet of older smaller line-
haul locomotives that could find their way into the switcher fleet,
essentially the only newly-built switchers put into service over the
last two decades have been of radically different design, employing one
to three smaller high-speed diesel engines designed for use in nonroad
applications. We are establishing new standards and special
certification provisions for newly-built and remanufactured switch
locomotives that take these factors into account.
    Locomotives spend a substantial amount of time idling, during which
they emit harmful pollutants, consume fuel, create noise, and increase
maintenance costs. We are requiring that idle controls, such as
Automatic Engine Stop/Start Systems (AESS), be included on all newly-
built Tier 3 and Tier 4 locomotives. We also are requiring that they be
installed on all existing locomotives that are subject to the new
remanufactured engine standards, at the point of first remanufacture
under the standards, unless already equipped with idle controls.
Additional idle emissions control beyond AESS is encouraged in our
program by factoring it into the certification test program.
(2) Marine Engine Emission Standards
    We are setting emissions standards for newly-built and
remanufactured marine diesel engines with displacements up to 30 liters
per cylinder (referred to as Category 1 and 2, or C1 and C2, engines).
Newly-built engines subject to the new standards include those used in
commercial, recreational, and auxiliary power applications, and those
below 37 kW (50 hp) that were previously regulated in our nonroad
diesel program.
    The new marine diesel engine standards include stringent engine-
based Tier 3 standards for newly-built marine diesel engines that phase
in beginning in 2009. These are followed by aftertreatment-based Tier 4
standards for engines above 600 kW (800 hp) that phase in beginning in
2014. The specific levels and implementation dates for the Tier 3 and
Tier 4 standards vary by engine size and power. This yields an array of
emission standards levels and start dates that help ensure the most
stringent standards feasible at the earliest possible time for each
group of newly-built marine engines, while helping engine and vessel
manufacturers implement the program in a manner that minimizes their
costs for emission reductions. The new standards and implementation
schedules, as well as their technological feasibility, are described in
detail in section III of this preamble.
    We are also adopting standards to address the considerable impact
of emissions from large marine diesel engines installed in vessels in
the existing fleet. These standards apply to commercial marine diesel
engines above 600 kW when these engines are remanufactured, and take
effect as soon as certified remanufacture systems are available. The
final requirements are different from the programmatic alternative on
which we sought comment in that there is no mandatory date by which
marine remanufacture systems must be made available. However, systems
for the larger Category 2 marine diesel engines are expected to become
available at the same time as the locomotive remanufacture systems for
similar engines, as early as 2008, because Category 2 marine diesel
engines are often derived from locomotive engines. This new marine
remanufacture program is described in more detail in section
III.B(2)(b). We intend to revisit this program in the future to
evaluate the extent to which remanufacture systems are being introduced
into the market without a mandatory requirement, and to determine if
the program should be extended to small commercial and recreational
engines as well.
    Taken together, the program elements described above constitute a
comprehensive program that addresses the problems caused by locomotive
and marine diesel emissions from both a near-term and long-term
perspective. It does this while providing for an orderly and cost-
effective implementation schedule for the railroads, vessel owners,
manufacturers, and remanufacturers.

B. Why Is EPA Taking This Action?

(1) Locomotives and Marine Diesels Contribute to Serious Air Pollution
Problems
    As we discuss extensively in both the proposal and today's action,
EPA strongly believes it is appropriate to take steps now to reduce
future emissions from locomotive and marine diesel engines. Emissions
from these engines generate significant emissions of PM2.5
and NOX that contribute to nonattainment of the National
Ambient Air Quality Standards for PM2.5 and ozone.
NOX is a key precursor to ozone and secondary PM formation.
These engines also emit hazardous air pollutants or air toxics, which
are associated with serious adverse health effects. Finally, emissions
from locomotive and marine diesel engines cause harm to public welfare,
including contributing to visibility impairment and other harmful
environmental impacts across the U.S.
    The health and environmental effects associated with these
emissions are a classic example of a negative externality (an activity
that imposes uncompensated costs on others). With a negative
externality, an activity's social cost (the cost borne to society
imposed as a result of the activity taking place) exceeds its private
cost (the cost to those directly engaged in the activity). In this
case, as described below and in section II, emissions from locomotives
and marine diesel engines and vessels impose public health and
environmental costs on society. However, these added costs are not
reflected in the costs of those using

these engines and equipment. The current market and regulatory scheme
do not correct this externality because firms in the market are
rewarded for minimizing their production costs, including the costs of
pollution control, and do not benefit from reductions in emissions. In
addition, firms that may take steps to use equipment that reduces air
pollution may find themselves at a competitive disadvantage compared to
firms that do not. The emission standards that EPA is finalizing help
address this market failure and reduce the negative externality from
these emissions by providing a regulatory incentive for engine and
locomotive manufacturers to produce engines and locomotives that emit
fewer harmful pollutants and for railroads and vessel builders and
owners to use those cleaner engines.
    Emissions from locomotive and marine diesel engines account for
substantial portions of the country's current ambient PM2.5
and NOX levels. We estimate that today these engines account
for about 20 percent of mobile source NOX emissions and
about 25 percent of mobile source diesel PM2.5 emissions.
Under this rulemaking, by 2030, NOX emissions from these
diesel engines will be reduced annually by 800,000 tons and
PM2.5 emissions by 27,000 tons, and these reductions will
grow beyond 2030 as fleet turnover to the cleanest engines continues.
    EPA has already taken steps to bring emissions levels from highway
and nonroad diesel vehicles and engines to very low levels over the
next decade, while the per horsepower-hour emission levels for
locomotive and marine diesel engines remain at much higher levels--
comparable to the emissions for highway trucks in the early 1990s.
    Both ozone and PM2.5 contribute to serious public health
problems, including premature mortality, aggravation of respiratory and
cardiovascular disease (as indicated by increased hospital admissions
and emergency room visits, school absences, loss work days, and
restricted activity days), changes in lung function and increased
respiratory symptoms, altered respiratory defense mechanisms, and
chronic bronchitis. Diesel exhaust is of special public health concern,
and since 2002 EPA has classified exposure to diesel exhaust as likely
to be carcinogenic to humans by inhalation from environmental
exposures.\4\ Recent studies are showing that populations living near
large diesel emission sources such as major roadways, rail yards, and
marine ports are likely to experience greater diesel exhaust exposure
levels than the overall U.S. population, putting them at greater health
risks.\5 6\
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    \4\ U.S. EPA (2002) Health Assessment Document for Diesel Engine
Exhaust. EPA/600/8-90/057F. Office of Research and Development,
Washington DC. This document is available electronically at http://
cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
    \5\ Kinnee, E.J.; Touman, J.S.; Mason, R.; Thurman, J.; Beidler,
A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile
emissions to road segments for air toxics modeling in an urban area.
Transport. Res. Part D 9: 139-150.
    \6\ State of California Air Resources Board. Roseville Rail Yard
Study. Stationary Source Division, October 14, 2004. This document
is available electronically at: http://www.arb.ca.gov/diesel/
documents/rrstudy.htm and State of California Air Resources Board.
Diesel Particulate Matter Exposure Assessment Study for the Ports of
Los Angeles and Long Beach, April 2006. This document is available
electronically at: http://www.arb.ca.gov/regact/marine2005/
portstudy0406.pdf.
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    EPA recently conducted an initial screening-level analysis \7\ of
selected marine port areas and rail yards to better understand the
populations that are exposed to diesel particulate matter (DPM)
emissions from these facilities.8 9 This screening-level
analysis focused on a representative selection of national marine ports
and rail yards.\10\ Of the 47 marine ports and 37 rail yards selected,
the results indicate that at least 13 million people, including a
disproportionate number of low-income households, African-Americans,
and Hispanics, living in the vicinity of these facilities, are being
exposed to ambient DPM levels that are 2.0 [mu]g/m3 and 0.2
[mu]g/m3 above levels found in areas further from these
facilities. Because those populations exposed to DPM emissions from
marine ports and rail yards are more likely to be low-income and
minority residents, these populations will benefit from the controls
being finalized in this action. The detailed findings of this study are
available in the public docket for this rulemaking.
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    \7\ This type of screening-level analysis is an inexact tool and
not appropriate for regulatory decisionmaking; it is useful in
beginning to understand potential impacts and for illustrative
purposes. Additionally, the emissions inventories used as inputs for
the analyses are not official estimates and likely underestimate
overall emissions because they are not inclusive of all emission
sources at the individual ports in the sample. For example, most
inventories included emissions from ocean-going vessels (powered by
Category 3 engines), as well as some commercial vessel categories,
including harbor crafts, (powered by Category 1 and 2 engines),
cargo handling equipment, locomotives, and heavy-duty vehicles. This
final rule will not address emissions from ocean-going vessels,
cargo handling equipment or heavy-duty vehicles.
    \8\ ICF International. September 28, 2007. Estimation of diesel
particulate matter concentration isopleths for marine harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \9\ ICF International. September 28, 2007. Estimation of diesel
particulate matter population exposure near selected harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \10\ The Agency selected a representative sample of the top 150
U.S. ports including coastal, inland, and Great Lake ports. In
selecting a sample of rail yards the Agency identified a subset from
the hundreds of rail yards operated by Class I Railroads.
---------------------------------------------------------------------------

    Today, millions of Americans continue to live in areas that do not
meet existing air quality standards. Currently, ozone concentrations
exceeding the 8-hour ozone NAAQS occur over wide geographic areas,
including most of the nation's major population centers. As of October
10, 2007, approximately 88 million people live in 39 designated areas
(which include all or part of 208 counties) that either do not meet the
current PM2.5 NAAQS or contribute to violations in other
counties, and 144 million people live in 81 areas (which include all or
part of 368 counties) designated as not in attainment for the 8-hour
ozone NAAQS. These numbers do not include the people living in areas
where there is a significant future risk of failing to maintain or
achieve either the current or future PM2.5 or ozone NAAQS.
    In addition to public health impacts, there are public welfare and
environmental impacts associated with ozone and PM2.5
emissions. Ozone causes damage to vegetation which leads to crop and
forestry economic losses, as well as harm to national parks, wilderness
areas, and other natural systems. NOX and direct emissions
of PM2.5 can contribute to the impairment of visibility in
many parts of the U.S., where people live, work, and recreate,
including national parks, wilderness areas, and mandatory class I
federal areas. The deposition of airborne particles can also reduce the
aesthetic appeal of buildings and culturally important objects through
soiling and can contribute directly (or in conjunction with other
pollutants) to structural damage by means of corrosion or erosion.
Finally, NOX emissions from diesel engines contribute to the
acidification, nitrification, and eutrophication of water bodies.
    While EPA has already adopted many emission control programs that
are expected to reduce ambient ozone and PM2.5 levels,
including the Clean Air Interstate Rule (CAIR) (70 FR 25162, May 12,
2005) and the Clean Air Nonroad Diesel Rule (69 FR 38957, June 29,
2004), the Heavy Duty Engine and Vehicle Standards and Highway Diesel
Fuel Sulfur Control Requirements (66 FR 5002, Jan. 18, 2001), and the
Tier 2 Vehicle and Gasoline Sulfur Program

(65 FR 6698, Feb. 10, 2000), the additional PM2.5 and
NOX emission reductions resulting from this rule will assist
states in attaining and maintaining the Ozone and the PM2.5
NAAQS both near term and in the decades to come.
    In September 2006, EPA finalized revised PM2.5 NAAQS
standards and over the next few years the EPA will undergo the process
of designating areas that do not meet this new standard. EPA modeling,
conducted as part of finalizing the revised NAAQS, projects that in
2015 up to 52 counties with 53 million people may violate either the
daily or annual standards for PM2.5 (or both), while an
additional 27 million people in 54 counties may live in areas that have
air quality measurements within 10 percent of the revised NAAQS. Even
in 2020 up to 48 counties, with 54 million people, may still not be
able to meet the revised PM2.5 NAAQS and an additional 25
million people, living in 50 counties, are projected to have air
quality measurements within 10 percent of the revised standards. The
locomotive and marine diesel PM2.5 reductions resulting from
this rulemaking are needed by a number of states to both attain and
maintain the revised PM2.5 NAAQS.
    State and local governments continue working to protect the health
of their citizens and comply with requirements of the Clean Air Act
(CAA or ``the Act''). As part of this effort they recognize the need to
secure additional major reductions in both diesel PM2.5 and
NOX emissions by undertaking numerous state-level
actions.11 However, they have also urged Agency action to
finalize a strong locomotive and marine diesel engine program that will
provide crucial emission reductions both in the near and longterm.
---------------------------------------------------------------------------

    \11\ Two examples of state and local actions are: California Air
Resources Board (2006). Emission Reduction Plan for Ports and Goods
Movements (April 2006), Available electronically at www.arb.ca.gov/
gmp/docs/finalgmpplan090905.pdf; Connecticut Department of
Environmental Protection (2006). Connecticut's Clean Diesel Plan
(January 2006). See http://www.dep.state.ct.us/air2/diesel/index.htm
for description of initiative.
---------------------------------------------------------------------------

    The federal program finalized today results in earlier and
significantly greater NOX and PM reductions from the
locomotive and marine sector than the proposed program because of the
first-ever national standards for remanufactured marine engines and the
starting of Tier 4 NOX requirements for line-haul
locomotives and for 2000-3700 kW (2760-4900 hp) marine engines two
years earlier than proposed. These changes reflect important
cooperative efforts by the regulated industry to implement cleaner
technology as early as possible. While the program finalized today will
help many states and communities achieve cleaner air, for some areas,
such as the South Coast of California, the reductions achieved through
this rule will not alone enable them to meet their near-term ozone and
PM air quality goals. This was also the case for our 1998 locomotive
rulemaking, where the State of California worked with Class I railroads
operating in southern California to develop a Memoranda of
Understanding (MOU) ensuring that the cleanest technologies enabled by
federal rules were expeditiously introduced in areas of California with
greatest air quality improvement needs. EPA continues to support
California's efforts to reconcile likely future growth in the
locomotive and marine sector with the public health protection needs of
the area, and today's final rule includes provisions which are well-
suited to encouraging early deployment of cleaner technologies through
the development of similar programs.
    In addition to these new standards, EPA has a number of voluntary
programs that help enable government, industry, and local communities
to address challenging air quality problems. The EPA SmartWay program
has worked with railroads to encourage them to reduce unnecessary
locomotive idling and will continue to promote the use of innovative
idle reduction technologies that can substantially reduce locomotive
emissions while reducing fuel consumption. EPA's National Clean Diesel
Campaign, through its Clean Ports USA program is working with port
authorities, terminal operators, and trucking and rail companies to
promote cleaner diesel technologies and emission reduction strategies
through education, incentives, and financial assistance. Part of these
efforts involves voluntary retrofit programs that can further reduce
emissions from the existing fleet of diesel engines. Finally, EPA is
implementing a new Sustainable Ports Strategy which will allow EPA to
partner with ports, business partners, communities and other
stakeholders to become world leaders in sustainability, including
achieving cleaner air. This new strategy builds on the success of
collaborative work EPA has been doing in partnership with the American
Association of Port Authorities (AAPA), and through port related
efforts of Clean Ports USA, SmartWay, EPA's Regional Diesel
Collaboratives and other programs. Together these approaches augment
the regulations being finalized today, helping states and communities
achieve larger reductions sooner in the areas of our country that need
them the most.
(2) Advanced Technologies Can Be Applied
    Air pollution from locomotive and marine diesel exhaust is a
challenging problem. However, we believe it can be addressed
effectively through a combination of engine-out emission reduction
technologies and high-efficiency catalytic aftertreatment technologies.
As discussed in greater detail in section III.C, the development of
these aftertreatment technologies for highway and nonroad diesel
applications has advanced rapidly in recent years, so that new engines
can achieve very large emission reductions in PM and NOX (in
excess of 90 and 80 percent, respectively).
    High-efficiency PM control technologies are being broadly used in
many parts of the world and are being used domestically to comply with
EPA's heavy-duty truck standards that started taking effect in the 2007
model year. These technologies are highly durable and robust in use and
have proved extremely effective in reducing exhaust hydrocarbon (HC)
and carbon monoxide emissions.
    Control of NOX emissions from locomotive and marine
diesel engines can also be achieved with high-efficiency exhaust
emission control technologies. Such technologies are expected to be
used to meet the stringent NOX standards included in EPA's
heavy-duty highway diesel and nonroad Tier 4 programs and have been in
production for heavy-duty trucks in Europe since 2005 and in many
stationary source applications throughout the world.
    Section III.C discusses additional engineering challenges in
applying these technologies to newly-built locomotive and marine
engines, as well as the development steps that we expect to be taken to
resolve the challenges. With the lead time available and the assurance
of ULSD for the locomotive and marine sectors in 2012, as provided by
our 2004 final rule for nonroad engines and fuel, we are confident the
application of advanced technology to locomotives and marine diesel
engines will proceed at a reasonable rate of progress and will result
in systems capable of achieving the new standards on time.
(3) Basis for Action Under the Clean Air Act
    Authority for the actions promulgated in this document is granted
to the EPA

by sections 114, 203, 205, 206, 207, 208, 213, 216, and 301(a) of the
Clean Air Act as amended in 1990 (42 U.S.C. 7414, 7522, 7524, 7525,
7541, 7542, 7547, 7550 and 7601(a)).
    Authority to Set Standards. EPA is promulgating emissions standards
for new marine diesel engines pursuant to its authority under section
213(a)(3) and (4) of the CAA. EPA is promulgating emission standards
for new locomotives and new engines used in locomotives pursuant to its
authority under section 213(a)(5) of the CAA.
    EPA has previously determined that certain existing locomotive
engines, when they are remanufactured, are returned to as-new condition
and are expected to have the same performance, durability, and
reliability as freshly-manufactured locomotive engines. Consequently we
set emission standards for these remanufactured engines that apply at
the time of remanufacture (defined as ``to replace, or inspect and
qualify, each and every power assembly of a locomotive or locomotive
engine, whether during a single maintenance event or cumulatively
within a five-year period * * *'' (see 61 FR 53102, October 4, 1996; 40
CFR 92.2). In this action we are adopting new tiers of standards for
both freshly manufactured and remanufactured locomotives and locomotive
engines.
    In the proposal for this rulemaking we also discussed applying a
similar approach to marine diesel engines. Many marine diesel engines,
particularly those above 600 kW (800 hp), periodically undergo a
maintenance process that returns them to as-new condition. A full
rebuild that brings an engine back to as-new condition includes a
complete overhaul of the engine, including piston, rings, liners,
turbocharger, heads, bearings, and geartrain/camshaft removal and
replacement. Engine manufacturers typically provide instructions for
such a full rebuild. Marine diesel engine owners complete this process
to maintain engine reliability, durability, and performance over the
life of their vessel, and to avoid the need to repower (replace the
engine) before their vessel wears out. A commercial marine vessel can
be in operation in excess of 40 years, which means that a marine diesel
engine may be remanufactured to as-new condition three or more times
before the vessel is scrapped.
    Because these remanufactured engines are returned to as-new
condition, section 213(a)(3) and (4) give EPA the authority to set
emission standards for those engines. We are adopting requirements for
remanufactured marine diesel engines, described in section III.B(2)(b)
of this action. For the purpose of this program, we are defining
remanufacture as the replacement of all cylinder liners, either in one
maintenance event or over the course of five years (for the purpose of
this program, ``replacement'' includes the removing, inspecting and
requalifying a liner). While replacement of cylinder liners is only one
element of a full rebuild, it is common to all rebuilds. Marine diesel
engines that do not have their cylinder liners replaced all at once or
within a five-year period, or that do not perform cylinder liner
replacement at all, are not considered to be returned to as-new
condition and therefore are not considered to be remanufactured. Those
engines will not be subject to the marine remanufacture requirements.
    Pollutants That Can Be Regulated. CAA section 213(a)(3) directs the
Administrator to set NOX, volatile organic compounds (VOCs),
or carbon monoxide standards for classes or categories of engines such
as marine diesel engines that contribute to ozone or carbon monoxide
concentrations in more than one nonattainment area. These (``standards
shall achieve the greatest degree of emission reduction achievable
through the application of technology which the Administrator
determines will be available for the engines or vehicles, giving
appropriate consideration to cost, lead time, noise, energy, and safety
factors associated with the application of such technology.''
    CAA section 213(a)(4) authorizes the Administrator to establish
standards to control emissions of pollutants which ``may reasonably be
anticipated to endanger public health and welfare'' where the
Administrator determines, as it has done for emissions of PM, that
nonroad engines as a whole contribute significantly to such air
pollution. The Administrator may promulgate regulations that are deemed
appropriate, taking into account costs, noise, safety, and energy
factors, for classes or categories of new nonroad vehicles and engines
which cause or contribute to such air pollution.
    Level of the Standards. CAA section 213(a)(5) directs EPA to adopt
emission standards for new locomotives and new engines used in
locomotives that achieve the ``greatest degree of emissions reductions
achievable through the use of technology that the Administrator
determines will be available for such vehicles and engines, taking into
account the cost of applying such technology within the available time
period, the noise, energy, and safety factors associated with the
applications of such technology.'' Section 213(a)(5) does not require
any review of the contribution of locomotive emissions to pollution,
though EPA does provide such information in this rulemaking. As
described in section III of this preamble and in chapter 4 of the final
Regulatory Impact Analysis (RIA), EPA has evaluated the available
information to determine the technology that will be available for
locomotives and engines subject to EPA standards.
    Certification and Implementation. EPA is also acting under its
authority to implement and enforce both the marine diesel emission
standards and the locomotive emission standards. Section 213(d)
provides that the standards EPA adopts for both new locomotive and
marine diesel engines ``shall be subject to sections 206, 207, 208, and
209'' of the Clean Air Act, with such modifications that the
Administrator deems appropriate to the regulations implementing these
sections. In addition, the locomotive and marine standards ``shall be
enforced in the same manner as [motor vehicle] standards prescribed
under section 202'' of the Act. Section 213(d) also grants EPA
authority to promulgate or revise regulations as necessary to determine
compliance with, and enforce, standards adopted under section 213.
    Technological Feasibility and Cost of Standards. The evidence
provided in section III.C of this Preamble and in chapter 4 of the RIA
indicates that the stringent emission standards we are setting today
for newly-built and remanufactured locomotive and marine diesel engines
are feasible and reflect the greatest degree of emission reduction
achievable through the use of technology that will be available in the
model years to which they apply. We have given appropriate
consideration to costs in setting these standards. Our review of the
costs and cost-effectiveness of these standards indicate that they will
be reasonable and comparable to the cost-effectiveness of other
emission reduction strategies that EPA has required in prior
rulemakings. We have also reviewed and given appropriate consideration
to the energy factors of this rule in terms of fuel efficiency as well
as any safety and noise factors associated with these standards.
    Health and Environmental Need for the Standards. The information in
section II of this Preamble and chapter 2 of the RIA regarding air
quality and public health impacts provides strong evidence that
emissions from marine diesel engines and locomotives significantly and
adversely impact public health or welfare. EPA has

already found in previous rules that emissions from new marine diesel
engines contribute to ozone and carbon monoxide concentrations in more
than one area which has failed to attain the ozone and carbon monoxide
NAAQS (64 FR 73300, December 29, 1999). EPA has also previously
determined that it is appropriate to establish PM standards for marine
diesel engines under section 213(a)(4), and the additional information
on the carcinogenicity of exposure to diesel exhaust noted above
reinforces this finding. In addition, we have already found that
emissions from nonroad engines as a whole significantly contribute to
air pollution that may reasonably be anticipated to endanger public
welfare due to regional haze and visibility impairment (67 FR 68241,
Nov. 8, 2002). We find here, based on the information in the NPRM and
in section II of this preamble and Chapters 2 and 3 of the final RIA,
that emissions from the new marine diesel engines likewise contribute
to regional haze and to visibility impairment.
    The PM and NOX emission reductions resulting from these
standards are important to states' efforts in attaining and maintaining
the ozone and the PM2.5 NAAQS in the near term and in the
decades to come. As noted above, the risk to human health and welfare
will be significantly reduced by the standards finalized in today's
action.

II. Air Quality and Health Impacts

    The locomotive and marine diesel engines subject to this final rule
generate significant emissions of particulate matter (PM) and nitrogen
oxides (NOX) that contribute to nonattainment of the
National Ambient Air Quality Standards (NAAQS) for PM2.5 and
ozone. These engines also emit hazardous air pollutants or air toxics
that are associated with serious adverse health effects and contribute
to visibility impairment and other harmful environmental impacts across
the U.S.
    By 2030, these standards are expected to reduce annual locomotive
and marine diesel engine PM2.5 emissions by 27,000 tons;
NOX emissions by 800,000 tons; and volatile organic compound
(VOC) emissions by 43,000 tons as well as reducing carbon monoxide (CO)
and toxic compounds known as air toxics.\12\
---------------------------------------------------------------------------

    \12\ Nationwide locomotive and marine diesel engines comprise
approximately 3 percent of the nonroad mobile sources hydrocarbon
inventory. EPA National Air Quality and Emissions Trends Report
1999. March 2001, Document Number: EPA 454/R-0-004. This document is
available in Docket EPA-HQ-OAR-2003-0190. This document is available
electronically at: http://www.epa.gov/air/airtrends/aqtrnd99/.
---------------------------------------------------------------------------

    We project that reductions of PM2.5, NOX, and
VOC emissions from locomotive and marine diesel engines will produce
nationwide air quality improvements. According to air quality modeling
performed in conjunction with this rule, all 39 current
PM2.5 nonattainment areas will experience a decrease in
their projected 2030 design values. Likewise the 133 mandatory class I
federal areas that EPA modeled will all see improvements in their
visibility. This rule will also result in nationwide ozone benefits. In
2030, 573 counties (of 579 that have monitored data) experience at
least a 0.1 ppb decrease in their ozone design values.

A. Overview

    From a public health perspective, we are concerned with locomotive
and marine diesel engines' contributions to atmospheric levels of
particulate matter in general, diesel PM2.5 in particular,
various gaseous air toxics, and ozone. Today, locomotive and marine
diesel engine emissions represent a substantial portion of the U.S.
mobile source diesel PM2.5 and NOX inventories,
approximately 20 percent of mobile source NOX and 25 percent
of mobile source diesel PM2.5. Over time, the relative
contribution of these diesel engines to air quality problems is
expected to increase as the emission contribution from other mobile
sources decreases and the usage of locomotives and marine vessels
increases. By 2030, without the additional emissions controls finalized
in today's rule, locomotive and marine diesel engines will emit about
65 percent of the total mobile source diesel PM2.5 emissions
and 35 percent of the total mobile source NOX emissions.
    Based on the most recent data available for this rule, air quality
problems continue to persist over a wide geographic area of the United
States. As of October 10, 2007 there are approximately 88 million
people living in 39 designated areas (which include all or part of 208
counties) that either do not meet the current PM2.5 NAAQS or
contribute to violations in other counties, and 144 million people
living in 81 areas (which include all or part of 366 counties)
designated as not in attainment for the 8-hour ozone NAAQS. These
numbers do not include the people living in areas where there is a
significant future risk of failing to maintain or achieve either the
current or future PM2.5 or ozone NAAQS. Figure II-1
illustrates the widespread nature of these problems. This figure
depicts counties which are currently designated nonattainment for
either or both the 8-hour ozone NAAQS and PM2.5 NAAQS. It
also shows the location of mandatory class I federal areas for
visibility.
BILLING CODE 6560-50-P

[GRAPHIC] [TIFF OMITTED] TR06MY08.000

BILLING CODE 6560-50-C
    The engine standards finalized in this rule will help reduce
emissions of PM, NOX, VOCs, CO, and air toxics and their
associated health and environmental effects. Emissions from locomotives
and diesel marine engines contribute to PM and ozone concentrations in
many, if not all, of these nonattainment areas.\13\ The engine
standards being finalized today will become effective as early as 2008,
making the expected PM2.5, NOX, and VOC inventory reductions
from this rulemaking critical to a number of states as they seek to
either attain or maintain the current PM2.5 or ozone NAAQS.
---------------------------------------------------------------------------

    \13\ See section II.B.(1)(c) and II.B.(2)(c) for a summary of
the impact emission reductions from locomotive and marine diesel
engines will have on air quality in current PM2.5 and ozone
nonattainment areas.
---------------------------------------------------------------------------

    Beyond the impact locomotive and marine diesel engines have on our
nation's ambient air quality the diesel

exhaust emissions from these engines are also of particular concern
since exposure to diesel exhaust is classified as likely to be
carcinogenic to humans by inhalation from environmental levels of
exposure.\14\ Many people spend a large portion of time in or near
areas of concentrated locomotive or marine diesel emissions, near rail
yards, marine ports, railways, and waterways. Recent studies show that
populations living near large diesel emission sources such as major
roadways,\15\ rail yards \16\ and marine ports \17\ are likely to
experience greater diesel exhaust exposure levels than the overall U.S.
population, putting them at a greater health risk.
---------------------------------------------------------------------------

    \14\ U.S. EPA (2002) Health Assessment Document for Diesel
Engine Exhaust. EPA/600/8-90/057F. Office of Research and
Development, Washington, DC. This document is available in Docket
EPA-HQ-OAR-2003-0190. This document is available electronically at
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
    \15\ Kinnee, E.J.; Touma, J.S.: Mason, R.; Thurman, J.; Beidler,
A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile
emissions to road segments for air toxics modeling in an urban area.
Transport. Res. Part D 9:139-150; also see Cohen, J.; Cook, R;
Bailey, C.R.; Carr, E. (2005) Relationship between motor vehicle
emissions of hazardous pollutants, roadway proximity, and ambient
concentrations in Portland, Oregon. Environ. Modeling & Software 20:
7-12.
    \16\ Hand, R.; Di, P; Servin, A.; Hunsaker, L.; Suer, C. (2004)
Roseville Rail Yard Study. California Air Resources Board. This
document is available in Docket EPA-HQ-OAR-2003-0190. [Online at
http://www.arb.ca.gov/diesel/documents/rrstudy.htm].
    \17\ Di P.; Servin, A.; Rosenkranz, K.; Schwehr, B.; Tran, H.
(April 2006); Diesel Particulate Matter Exposure Assessment Study
for the Ports of Los Angeles and Long Beach. State of California Air
Resources Board.
---------------------------------------------------------------------------

    EPA recently conducted an initial screening-level analysis \18\ of
selected marine port areas and rail yards to better understand the
populations that are exposed to diesel particulate matter (DPM)
emissions from these facilities.19 20 This screening-level
analysis focused on a representative selection of national marine ports
and rail yards.\21\ Of the 47 marine ports and 37 rail yards selected,
the results indicate that at least 13 million people, including a
disproportionate number of low-income households, African-Americans,
and Hispanics, living in the vicinity of these facilities, are being
exposed to ambient DPM levels that are 2.0 [mu]g/m3 and 0.2
[mu]g/m3 above levels found in areas further from these
facilities. Because those populations exposed to DPM emissions from
marine ports and rail yards are more likely to be low-income and
minority residents, these populations will benefit from the controls
being finalized in this action. The detailed findings of this study are
available in the public docket for this rulemaking.
---------------------------------------------------------------------------

    \18\ This type of screening-level analysis is an inexact tool
and not appropriate for regulatory decision-making; it is useful in
beginning to understand potential impacts and for illustrative
purposes. Additionally, the emissions inventories used as inputs for
the analyses are not official estimates and likely underestimate
overall emissions because they are not inclusive of all emission
sources at the individual ports in the sample. For example, most
inventories included emissions from ocean-going vessels (powered by
Category 3 engines), as well as some commercial vessel categories,
including harbor crafts (powered by Category 1 and 2 engines), cargo
handling equipment, locomotives, and heavy-duty vehicles. This final
rule will not address emissions from ocean-going vessels, cargo
handling equipment or heavy-duty vehicles.
    \19\ ICF International. September 28, 2007. Estimation of diesel
particulate matter concentration isopleths for marine harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \20\ ICF International. September 28, 2007. Estimation of diesel
particulate matter population exposure near selected harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \21\ The Agency selected a representative sample of the top 150
U.S. ports including coastal, inland and Great Lake ports. In
selecting a sample of rail yards the Agency identified a subset from
the hundreds of rail yards operated by Class I Railroads.
---------------------------------------------------------------------------

    In the following sections we review important public health effects
linked to pollutants emitted from locomotive and marine diesel engines.
First, the human health effects caused by the pollutants and their
current and projected ambient levels are discussed. Following the
discussion of health effects, the modeled air quality benefits
resulting from this action and the welfare effects associated with
emissions from diesel engines are presented. Finally, the locomotive
and marine engine emission inventories for the primary pollutants
affected by this rule are provided. In summary, the emission reductions
from this rule will contribute to controlling the health and welfare
problems associated with ambient PM and ozone levels and with diesel-
related air toxics.
    Taken together, the materials in this section and in the proposal
describe the need for tightened emission standards for both locomotive
and marine diesel engines and the air quality and public health
benefits resulting from this program. This section is not an exhaustive
treatment of these issues. For a fuller understanding of the topics
treated here, you should refer to the extended presentations in Chapter
2, 3 and 5 of the Regulatory Impact Analysis (RIA) accompanying this
final rule.

B. Public Health Impacts

(1) Particulate Matter
    The locomotive and marine engine standards detailed in this action
will result in significant reductions in primary (directly emitted)
PM2.5 emissions. In addition, the standards finalized today will reduce
emissions of NOX and VOCs, which contribute to the formation
of secondary PM2.5. Locomotive and marine diesel engines emit high
levels of NOX, which react in the atmosphere to form
secondary PM2.5 (namely ammonium nitrate). These engines also emit SO2
and VOC, which react in the atmosphere to form secondary PM2.5 composed
of sulfates and organic carbonaceous PM2.5. This rule will reduce both
primary and secondary PM.
(a) Background
    Particulate matter (PM) 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. PM is further described
by breaking it down into size fractions. PM10 refers to particles
generally less than or equal to 10 micrometers ([mu]m) in diameter.
PM2.5 refers to fine particles, generally less than or equal to 2.5
[mu]m in diameter. Inhalable (or ``thoracic'') coarse particles refer
to those particles generally greater than 2.5 [mu]m but less than or
equal to 10 [mu]m in diameter. Ultrafine PM refers to particles less
than 100 nanometers (0.1 [mu]m) in diameter. Larger particles tend to
be removed by the respiratory clearance mechanisms (e.g. coughing),
whereas smaller particles are deposited deeper in the lungs.
    Fine particles are produced primarily by combustion processes and
by transformations of gaseous emissions (e.g., SOx, NOX and
VOC) in the atmosphere. The chemical and physical properties of PM2.5
may vary greatly with time, region, meteorology, and source category.
Thus, PM2.5 may include a complex mixture of different pollutants
including sulfates, nitrates, organic compounds, elemental carbon and
metal compounds. These particles can remain in the atmosphere for days
to weeks and travel hundreds to thousands of kilometers.
    The primary PM2.5 NAAQS includes a short-term (24-hour)
and a long-term (annual) standard. The 1997 PM2.5 NAAQS
established by EPA set the 24-hour standard at a level of 65 [mu]g/
m3 based on the 98th percentile concentration averaged over
three years. The annual standard specifies an

expected annual arithmetic mean not to exceed 15 [mu]g/m3
averaged over three years.
    EPA has recently amended the NAAQS for PM2.5 (71 FR
61144, October 17, 2006). The final rule, signed on September 21, 2006,
addressed revisions to the primary and secondary NAAQS for PM to
provide increased protection of public health and welfare,
respectively. The level of the 24-hour PM2.5 NAAQS was
revised from 65 [mu]g/m3 to 35 [mu]g/m3 and the
level of the annual PM2.5 NAAQS was retained at 15 [mu]g/
m3. With regard to the secondary standards for
PM2.5, EPA has revised these standards to be identical in
all respects to the revised primary standards.
(b) Health Effects of PM2.5
    Scientific studies show ambient PM is associated with a series of
adverse health effects. These health effects are discussed in detail in
the 2004 EPA Particulate Matter Air Quality Criteria Document (PM
AQCD), and the 2005 PM Staff Paper.22 23 Further discussion
of health effects associated with PM can also be found in the RIA for
this rule.
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    \22\ U.S. EPA (2004) Air Quality Criteria for Particulate Matter
(Oct 2004), Volume I Document No. EPA600/P-99/002aF and Volume II
Document No. EPA600/P-99/002bF. This document is available in Docket
EPA-HQ-OAR-2003-0190.
    \23\ U.S. EPA (2005) Review of the National Ambient Air Quality
Standard for Particulate Matter: Policy Assessment of Scientific and
Technical Information, OAQPS Staff Paper. EPA-452/R-05-005. This
document is available in Docket EPA-HQ-OAR-2003-0190.
---------------------------------------------------------------------------

    Health effects associated with short-term exposures (hours to days)
to ambient PM include premature mortality, increased hospital
admissions, heart and lung diseases, increased cough, adverse lower-
respiratory symptoms, decrements in lung function and changes in heart
rate rhythm and other cardiac effects. Studies examining populations
exposed to different levels of air pollution over a number of years,
including the Harvard Six Cities Study and the American Cancer Society
Study, show associations between long-term exposure to ambient
PM2.5 and both total and cardiovascular and respiratory
mortality.\24\ In addition, a reanalysis of the American Cancer Society
Study shows an association between fine particle and sulfate
concentrations and lung cancer mortality.\25\
---------------------------------------------------------------------------

    \24\ Dockery, DW; Pope, CA III: Xu, X; et al. 1993. An
association between air pollution and mortality in six U.S. cities.
N Engl J Med 329:1753-1759.
    \25\ Pope, C. A., III; Burnett, R. T.; Thun, M. J.; Calle, E.
E.; Krewski, D.; Ito, K.; Thurston, G. D. (2002) Lung cancer,
cardiopulmonary mortality, and long-term exposure to fine
particulate air pollution. J. Am. Med. Assoc. 287:1132-1141.
---------------------------------------------------------------------------

    The health effects of PM2.5 have been further documented
in local impact studies which have focused on health effects due to
PM2.5 exposures measured on or near roadways. These studies
take into account all air pollution sources, including both spark-
ignition (gasoline) and diesel powered vehicles, and indicate that
exposure to PM2.5 emissions near roadways, which are
dominated by mobile sources, are associated with potentially serious
health effects. For instance, a recent study found associations between
concentrations of cardiac risk factors in the blood of healthy young
police officers and PM2.5 concentrations measured in
vehicles.26 Also, a number of studies have shown
associations between residential or school outdoor concentrations of
some fine particle constituents that are found in motor vehicle
exhaust, and adverse respiratory outcomes, including asthma prevalence
in children who live near major roadways.27 28 29 Although
the engines considered in this rule differ from those in these studies
with respect to their applications and fuel qualities, these studies
provide an indication of the types of health effects that might be
expected to be associated with personal exposure to PM2.5
emissions from large marine diesel and locomotive engines.
---------------------------------------------------------------------------

    \26\ Riediker, M.; Cascio, W.E.; Griggs, T.R.; et al. (2004)
Particulate matter exposure in cars is associated with
cardiovascular effects in healthy young men. Am J Respir Crit Care
Med 169: 934-940.
    \27\ Van Vliet, P.; Knape, M.; de Hartog, J.; Janssen, N.;
Harssema, H.; Brunekreef, B. (1997). Motor vehicle exhaust and
chronic respiratory symptoms in children living near freeways. Env.
Research 74: 122-132.
    \28\ Brunekreef, B., Janssen, N.A.H.; de Hartog, J.; Harssema,
H.; Knape, M.; van Vliet, P. (1997). Air pollution from truck
traffic and lung function in children living near roadways.
Epidemiology 8:298-303.
    \29\ Kim, J.J.; Smorodinsky, S.; Lipsett, M.; Singer, B.C.;
Hodgson, A.T.; Ostro, B. (2004). Traffic-related air pollution near
busy roads: The East Bay children's respiratory health study. Am. J.
Respir. Crit. Care Med. 170: 520-526.
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    Recent new studies from the State of California provide evidence
that PM2.5 emissions within marine ports and rail yards can
contribute significantly to elevated ambient concentrations near these
sources.30 31 A substantial number of people experience
exposure to locomotive and marine diesel engine emissions, raising
potential health concerns. The controls finalized in this action will
help reduce exposure to PM2.5, specifically exposure to
marine port and rail yard related diesel PM2.5 sources.
Additional information on marine port and rail yard emissions and
ambient exposures can be found in Chapter 2 of the RIA.
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    \30\ State of California Air Resources Board. Roseville Rail
Yard Study. Stationary Source Division, October 14, 2004. This
document is available in Docket EPA-HQ-OAR-2003-0190. This document
is available electronically at: http://www.arb.ca.gov/diesel/
documents/rrstudy.htm.
    \31\ State of California Air Resources Board. Diesel Particulate
Matter Exposure Assessment Study for the Ports of Los Angeles and
Long Beach, April 2006. This document is available in Docket EPA-HQ-
OAR-2003-0190. This document is available electronically at: ftp://
ftp.arb.ca.gov/carbis/msprog/offroad/marinevess/documents/
portstudy0406.pdf.
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(c) Current and Projected PM2.5 Levels
    PM2.5 concentrations exceeding the level of the
PM2.5 NAAQS occur in many parts of the country.\32\ In 2005
EPA designated 39 nonattainment areas for the 1997 PM2.5
NAAQS (70 FR 943, January 5, 2005). These areas are comprised of 208
full or partial counties with a total population exceeding 88 million.
The 1997 PM2.5 NAAQS was recently revised and the 2006
PM2.5 NAAQS became effective on December 18, 2006. Table II-
1 presents the number of counties in areas currently designated as
nonattainment for the 1997 PM2.5 NAAQS as well as the number
of additional counties that have monitored data that is violating the
2006 PM2.5 NAAQS.
---------------------------------------------------------------------------

    \32\ A listing of the PM2.5 nonattainment areas is
included in the RIA for this rule.

  Table II-1.--Fine Particle Standards: Current Nonattainment Areas and
                        Other Violating Counties
------------------------------------------------------------------------
   Nonattainment areas/other violating       Number of
                counties                     counties      Population a
------------------------------------------------------------------------
1997 PM2.5 Standards: 39 areas currently             208      88,394,000
 designated.............................
2006 PM2.5 Standards: counties with                   49      18,198,676
 violating monitors b...................
                                         -------------------------------
    Total...............................             257    106,595,676
------------------------------------------------------------------------
Notes:
(a) Population numbers are from 2000 census data.
(b) This table provides an estimate of the counties violating the 2006
  PM2.5 NAAQS based on 2003-05 air quality data. The areas designated as
  nonattainment for the 2006 PM2.5 NAAQS will be based on 3 years of air
  quality data from later years. Also, the county numbers in the summary
  table includes only the counties with monitors violating the 2006
  PM2.5 NAAQS. The monitored county violations may be an underestimate
  of the number of counties and populations that will eventually be
  included in areas with multiple counties designated nonattainment.

    A number of state governments have told EPA that they need the
reductions this rule will provide in order to meet and maintain the
PM2.5 NAAQS. Areas designated as not attaining the 1997
PM2.5 NAAQS will need to attain the 1997 standards in the
2010 to 2015 time frame, and then maintain them thereafter. The
attainment dates associated with the potential new 2006
PM2.5 nonattainment areas are likely to be in the 2015 to
2020 timeframe. The emission standards finalized in this action become
effective as early as 2008 making the NOX, PM, and VOC
inventory reductions from this rulemaking useful to states in attaining
or maintaining the PM2.5 NAAQS.
    EPA has already adopted many emission control programs that are
expected to reduce ambient PM2.5 levels and which will
assist in reducing the number of areas that fail to achieve the
PM2.5 NAAQS. Even so, our air quality modeling for this
final rule projects that in 2020, with all current controls but
excluding the reductions achieved through this rule, up to 11 counties
with a population of 24 million may not attain the current annual
PM2.5 standard of 15 [mu]g/m3. These numbers do
not account for additional areas that have air quality measurements
within 10 percent of the annual PM2.5 standard. These areas,
although not violating the standards, will also benefit from the
additional reductions from this rule ensuring long-term maintenance of
the PM2.5 NAAQS.
    Air quality modeling performed for this final rule shows that in
2020 and 2030 all 39 current PM2.5 nonattainment areas will
experience decreases in their PM2.5 design values. For areas
with current PM2.5 design values greater than 15 [mu]g/
m3 the modeled future-year population weighted
PM2.5 design values are expected to decrease on average by
0.08 [mu]g/m3 in 2020 and by 0.16 [mu]g/m3 in
2030. The maximum decrease for future-year PM2.5 design
values will be 0.38 [mu]g/m3 in 2020 and 0.81 [mu]g/
m3 in 2030. The air quality modeling methodology and the
projected reductions are discussed in more detail in Chapter 2 of the
RIA.
(2) Ozone
    The locomotive and marine engine standards finalized in this action
are expected to result in significant reductions of NOX and
VOC emissions. NOX and VOC contribute to the formation of
ground-level ozone pollution or smog. People in many areas across the
U.S. continue to be exposed to unhealthy levels of ambient ozone.
(a) Background
    Ground-level ozone pollution is typically formed by the reaction of
volatile organic compounds (VOC) and nitrogen oxides (NOX)
in the lower atmosphere in the presence of heat and sunlight. These
pollutants, often referred to as ozone precursors, are emitted by many
types of pollution sources, such as highway and nonroad motor vehicles
and engines, power plants, chemical plants, refineries, makers of
consumer and commercial products, industrial facilities, and smaller
area sources.
    The science of ozone formation, transport, and accumulation is
complex.\33\ Ground-level ozone is produced and destroyed in a cyclical
set of chemical reactions, many of which are sensitive to temperature
and sunlight. When ambient temperatures and sunlight levels remain high
for several days and the air is relatively stagnant, ozone and its
precursors can build up and result in more ozone than typically occurs
on a single high-temperature day. Ozone can also be transported into an
area from pollution sources found hundreds of miles upwind, resulting
in elevated ozone levels even in areas with low local VOC or
NOX emissions.
---------------------------------------------------------------------------

    \33\ U.S. EPA Air Quality Criteria for Ozone and Related
Photochemical Oxidants (Final). U.S. Environmental Protection
Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document
is available in Docket EPA-HQ-OAR-2003-0190. This document may be
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/
ozone/s_o3_cr_cd.html.
---------------------------------------------------------------------------

    The current ozone NAAQS, established by EPA in 1997, has an 8-hour
averaging time. The 8-hour ozone NAAQS is met at an ambient air quality
monitoring site when the average of the annual fourth-highest daily
maximum 8-hour average ozone concentration over three years is less
than or equal to 0.084 ppm. On June 20, 2007, EPA proposed to
strengthen the ozone NAAQS, the proposed revisions reflect new
scientific evidence about ozone and its effects on people and public
welfare.\34\ The final ozone NAAQS rule is scheduled for March 2008.
---------------------------------------------------------------------------

    \34\ EPA proposed to set the 8-hour primary ozone standard to a
level within the range of 0.070-0.075 ppm. The agency also requested
comments on alternative levels of the 8-hour primary ozone standard,
within a range from 0.060 ppm up to and including retention of the
current standard (0.084 ppm). EPA also proposed two options for the
secondary ozone standard. One option would establish a new form of
standard designed specifically to protect sensitive plants from
damage caused by repeated ozone exposure throughout the growing
season. This cumulative standard would add daily ozone
concentrations across a three-month period. EPA proposed to set the
level of the cumulative standard within the range of 7 to 21 ppm-
hours. The other option would follow the current practice of making
the secondary standard equal to the proposed 8-hour primary
standard.
---------------------------------------------------------------------------

(b) Health Effects of Ozone
    The health and welfare effects of ozone are well documented and are
assessed in EPA's 2006 ozone Air Quality Criteria Document (ozone AQCD)
and EPA Staff Paper.35, 36 Ozone

can irritate the respiratory system, causing coughing, throat
irritation, and/or uncomfortable sensation in the chest. Ozone can
reduce lung function and make it more difficult to breathe deeply;
breathing may also become more rapid and shallow than normal, thereby
limiting a person's activity. Ozone can also aggravate asthma, leading
to more asthma attacks that require medical attention and/or the use of
additional medication. There is evidence of an elevated risk of
mortality associated with acute exposure to ozone, especially in the
summer or warm season when ozone levels are typically high. Animal
toxicological evidence indicates that with repeated exposure, ozone can
inflame and damage the lining of the lungs, which may lead to permanent
changes in lung tissue and irreversible reductions in lung function.
People who are more susceptible to effects associated with exposure to
ozone can include children, the elderly, and individuals with
respiratory disease such as asthma. Those with greater exposures to
ozone, for instance due to time spent outdoors (e.g., children and
outdoor workers), are also of particular concern.
---------------------------------------------------------------------------

    \35\ U.S. EPA Air Quality Criteria for Ozone and Related
Photochemical Oxidants (Final). U.S. Environmental Protection
Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document
is available in Docket EPA-HQ-OAR-2003-0190. This document may be
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/
ozone/s_o3_cr_cd.html.
    \36\ U.S. EPA (2007) Review of the National Ambient Air Quality
Standards for Ozone, Policy Assessment of Scientific and Technical
Information. OAQPS Staff Paper.EPA-452/R-07-003. This document is
available in Docket EPA-HQ-OAR-2003-0190. This document is available
electronically at: http:www.epa.gov/ttn/naaqs/standards/ozone/s_
o3_cr_sp.html.
---------------------------------------------------------------------------

    The recent ozone AQCD also examined relevant new scientific
information that has emerged in the past decade, including the impact
of ozone exposure on such health effects as changes in lung structure
and biochemistry, inflammation of the lungs, exacerbation and causation
of asthma, respiratory illness-related school absence, hospital
admissions and premature mortality. Animal toxicological studies have
suggested potential interactions between ozone and PM with increased
responses observed to mixtures of the two pollutants compared to either
ozone or PM alone. The respiratory morbidity observed in animal studies
along with the evidence from epidemiologic studies supports a causal
relationship between acute ambient ozone exposures and increased
respiratory-related emergency room visits and hospitalizations in the
warm season. In addition, there is suggestive evidence of a
contribution of ozone to cardiovascular-related morbidity and non-
accidental and cardiopulmonary mortality.
(c) Current and Projected Ozone Levels
    Ozone concentrations exceeding the level of the 8-hour ozone NAAQS
occur over wide geographic areas, including most of the nation's major
population centers.\37\ As of October 10, 2007, there were
approximately 144 million people living in 81 areas (which include all
or part of 366 counties) designated as not in attainment with the 8-
hour ozone NAAQS. These numbers do not include the people living in
areas where there is a future risk of failing to maintain or attain the
8-hour ozone NAAQS.
---------------------------------------------------------------------------

    \37\ A listing of the 8-hour ozone nonattainment areas is
included in the RIA for this rule.
---------------------------------------------------------------------------

    States with 8-hour ozone nonattainment areas are required to take
action to bring those areas into compliance in the future. Based on the
final rule designating and classifying 8-hour ozone nonattainment areas
(69 FR 23951, April 30, 2004), most 8-hour ozone nonattainment areas
will be required to attain the ozone NAAQS in the 2007 to 2013 time
frame and then maintain the NAAQS thereafter.\38\ Many of these
nonattainment areas will need to adopt additional emission reduction
programs and the NOX and VOC reductions from this final
action are particularly important for these states. In addition, EPA's
review of the ozone NAAQS is currently underway with a final rule
scheduled for March 2008. If the ozone NAAQS is revised then new
nonattainment areas will be designated. While EPA is not relying on it
for purposes of justifying this rule, the emission reductions from this
rulemaking will also be helpful to states if EPA revises the ozone
NAAQS to be more stringent.
---------------------------------------------------------------------------

    \38\ The Los Angeles South Coast Air Basin 8-hour ozone
nonattainment area will have to attain before June 15, 2021.
---------------------------------------------------------------------------

    EPA has already adopted many emission control programs that are
expected to reduce ambient ozone levels. These control programs are
described in section I.B.1 of this preamble. As a result of these
programs, the number of areas that fail to meet the 8-hour ozone NAAQS
in the future is expected to decrease. Based on the air quality
modeling performed for this rule, which does not include any additional
local controls, we estimate nine counties (where 22 million people are
projected to live) will exceed the 8-hour ozone NAAQS in 2020.\39\ An
additional 39 counties (where 29 million people are projected to live)
are expected to be within 10 percent of violating the 8-hour ozone
NAAQS in 2020.
---------------------------------------------------------------------------

    \39\ We expect many of the 8-hour ozone nonattainment areas to
adopt additional emission reduction programs but we are unable to
quantify or rely upon future reductions from additional state and
local programs that have not yet been adopted.
---------------------------------------------------------------------------

    This rule results in reductions in nationwide ozone levels. The air
quality modeling projects that in 2030, 573 counties (of 579 that have
monitored data) experience at least a 0.1 ppb decrease in their ozone
design values. There are three nonattainment areas in southern
California, the Los Angeles-South Coast Air Basin nonattainment area,
the Riverside Co. (Coachella Valley) nonattainment area and the Los
Angeles--San Bernardino (W. Mojave) nonattainment area, which will
experience 8-hour ozone design value increases due to the
NOX disbenefits which occur in these VOC-limited ozone
nonattainment areas. Briefly, NOX reductions at certain
times and in some areas can lead to increased ozone levels. The air
quality modeling methodology (Section 2.3), the projected reductions
(Section 2.2.4), and the limited NOX disbenefits (Section
<IP_ADDRESS>.1), are discussed in more detail in Chapter 2 of the RIA.
    Results from the air quality modeling conducted for this final rule
indicate that the locomotive and marine diesel engine emission
reductions in 2020 and 2030 will improve both the average and
population-weighted average ozone concentrations for the U.S. In
addition, the air quality modeling shows that on average this final
rule will help bring counties closer to ozone attainment as well as
assist counties whose ozone concentrations are within ten percent below
the standard. For example, in projected nonattainment counties, on a
population-weighted basis, the 8-hour ozone design value will on
average decrease by 0.13 ppb in 2020 and 0.62 ppb in 2030.\40\
---------------------------------------------------------------------------

    \40\ Ozone design values are reported in parts per million (ppm)
as specified in 40 CFR part 50. Due to the scale of the design value
changes in this action, results have been presented in parts per
billion (ppb) format.
---------------------------------------------------------------------------

    The impact of the reductions has also been analyzed with respect to
those areas that have the highest design values, at or above 85 ppb, in
2020. We project there will be nine U.S. counties with design values at
or above 85 ppb in 2020. After implementation of this rule, we project
that one of these nine counties will drop below 85 ppb. Further, two of
the nine counties will be at least 10 percent closer to a design value
of less than 85 ppb, and on average all nine counties will be about 18
percent closer to a design value of less than 85 ppb.
(3) Air Toxics
    People experience elevated risk of cancer and other noncancer
health effects from exposure to the class of pollutants known
collectively as ``air toxics''. Mobile sources are responsible for a
significant portion of this exposure. According to the National Air
Toxic Assessment (NATA) for 1999, mobile sources, including locomotive
and marine diesel marine engines, were

responsible for 44 percent of outdoor toxic emissions and almost 50
percent of the cancer risk among the 133 pollutants quantitatively
assessed in the 1999 NATA. Benzene is the largest contributor to cancer
risk of all the assessed pollutants and mobile sources were responsible
for about 68 percent of all benzene emissions in 1999. Although the
1999 NATA did not quantify cancer risks associated with exposure to
diesel exhaust, EPA has concluded that diesel exhaust ranks with other
emissions that the national-scale assessment suggests pose the greatest
relative risk.
    According to the 1999 NATA, nearly the entire U.S. population was
exposed to an average level of air toxics that has the potential for
adverse respiratory noncancer health effects. This potential was
indicated by a hazard index (HI) greater than 1.\41\ Mobile sources
were responsible for 74 percent of the potential noncancer hazard from
outdoor air toxics in 1999. About 91 percent of this potential
noncancer hazard was from acrolein; \42\ however, the confidence in the
RfC for acrolein is medium 43 and confidence in NATA
estimates of population noncancer hazard from ambient exposure to this
pollutant is low.\44\ It is important to note that NATA estimates of
noncancer hazard do not include the adverse health effects associated
with particulate matter identified in EPA's Particulate Matter Air
Quality Criteria Document. Gasoline and diesel engine emissions
contribute significantly to particulate matter concentration.
---------------------------------------------------------------------------

    \41\ To express chronic noncancer hazards, we used the RfC as
part of a calculation called the hazard quotient (HQ), which is the
ratio between the concentration to which a person is exposed and the
RfC. (RfC is defined by EPA as, ``an estimate of a continuous
inhalation exposure to the human population, including sensitive
subgroups, with uncertainty spanning perhaps an order of magnitude,
which is likely to be without appreciable risks of deleterious
noncancer effects during a lifetime.'') A value of the HQ less than
one indicates that the exposure is lower than the RfC and that no
adverse health effects would be expected. Combined noncancer hazards
were calculated using the hazard index (HI), defined as the sum of
hazard quotients for individual air toxic compounds that affect the
same target organ or system. As with the hazard quotient, a value of
the HI at or below 1.0 will likely not result in adverse effects
over a lifetime of exposure. However, a value of the HI greater than
1.0 does not necessarily suggest a likelihood of adverse effects.
Furthermore, the HI cannot be translated into a probability that
adverse effects will occur and is not likely to be proportional to
risk.
    \42\ U.S. EPA (2006) National-Scale Air Toxics Assessment for
1999. This material is available electronically at http://
www.epa.gov/ttn/atw/nata1999/risksum.html.
    \43\ U.S. EPA (2003) Integrated Risk Information System File of
Acrolein. National Center for Environmental Assessment, Office of
Research and Development, Washington, D.C. 2003. This material is
available electronically at http://www.epa.gov/iris/subst/0364.htm.
    \44\ U.S. EPA (2006) National-Scale Air Toxics Assessment for
1999. This material is available electronically at http://
www.epa.gov/ttn/atw/nata1999/risksum.html.
---------------------------------------------------------------------------

    The NATA modeling framework has a number of limitations which
prevent its use as the sole basis for setting regulatory standards.
These limitations and uncertainties are discussed on the 1999 NATA
website.\45\ Even so, this modeling framework is very useful in
identifying air toxic pollutants and sources of greatest concern,
setting regulatory priorities, and informing the decision making
process.
---------------------------------------------------------------------------

    \45\ U.S. EPA (2006) National-Scale Air Toxics Assessment for
1999. http://www.epa.gov/ttn/atw/nata1999.
---------------------------------------------------------------------------

    The following section provides a brief overview of air toxics which
are associated with nonroad engines, including locomotive and marine
diesel engines, and provides a discussion of the health risks
associated with each air toxic.
(a) Diesel Exhaust (DE)
    Locomotive and marine diesel engines emit diesel exhaust (DE), a
complex mixture comprised of carbon dioxide, oxygen, nitrogen, water
vapor, carbon monoxide, nitrogen compounds, sulfur compounds and
numerous low-molecular-weight hydrocarbons. A number of these gaseous
hydrocarbon components are individually known to be toxic, including
aldehydes, benzene and 1,3-butadiene. The diesel particulate matter
(DPM) present in diesel exhaust consists of fine particles (< 2.5
[mu]m), including a subgroup with a large number of ultrafine particles
(< 0.1 [mu]m). These particles have a large surface area which makes
them an excellent medium for adsorbing organics and their small size
makes them highly respirable and able to reach the deep lung. Many of
the organic compounds present on the particles and in the gases are
individually known to have mutagenic and carcinogenic properties.
Diesel exhaust varies significantly in chemical composition and
particle sizes between different engine types (heavy-duty, light-duty),
engine operating conditions (idle, accelerate, decelerate), and fuel
formulations (high/low sulfur fuel). Also, there are emissions
differences between on-road and nonroad engines because the nonroad
engines are generally of older technology. This is especially true for
locomotive and marine diesel engines.\46\
---------------------------------------------------------------------------

    \46\ U.S. EPA (2002) Health Assessment Document for Diesel
Engine Exhaust. EPA/600/8-90/057F Office of Research and
Development, Washington DC. Pp1-1 1-2. This document is available
electronically at http://cfpub.epa.gov/ncea/cfm/
recordisplay.cfm?deid=29060. This document can be found in Docket
EPA-HQ-OAR-2003-0190.
---------------------------------------------------------------------------

    After being emitted in the engine exhaust, diesel exhaust undergoes
dilution as well as chemical and physical changes in the atmosphere.
The lifetime for some of the compounds present in diesel exhaust ranges
from hours to days.
(i) Diesel Exhaust: Potential Cancer Effects
    In EPA's 2002 Diesel Health Assessment Document (Diesel HAD),\47\
exposure to diesel exhaust was classified as likely to be carcinogenic
to humans by inhalation from environmental exposures, in accordance
with the revised draft 1996/1999 EPA cancer guidelines. A number of
other agencies (National Institute for Occupational Safety and Health,
the International Agency for Research on Cancer, the World Health
Organization, California EPA, and the U.S. Department of Health and
Human Services) have made similar classifications. However, EPA also
concluded in the Diesel HAD that it is not possible currently to
calculate a cancer unit risk for diesel exhaust due to a variety of
factors that limit the current studies, such as limited quantitative
exposure histories in occupational groups investigated for lung cancer.
---------------------------------------------------------------------------

    \47\ U.S. EPA (2002) Health Assessment Document for Diesel
Engine Exhaust. EPA/600/8-90/057F Office of Research and
Development, Washington, DC. This document is available
electronically at http://cfpub.epa.gov/ncea/cfm/
recordisplay.cfm?deid=29060. This document can be found in Docket
EPA-HQ-OAR-2003-0190.
---------------------------------------------------------------------------

    For the Diesel HAD, EPA reviewed 22 epidemiologic studies on the
subject of the carcinogenicity of workers exposed to diesel exhaust in
various occupations, finding increased lung cancer risk, although not
always statistically significant, in 8 out of 10 cohort studies and 10
out of 12 case-control studies within several industries, including
railroad workers. Relative risk for lung cancer associated with
exposure ranged from 1.2 to 1.5, although a few studies show relative
risks as high as 2.6. Additionally, the Diesel HAD also relied on two
independent meta-analyses, which examined 23 and 30 occupational
studies respectively, which found statistically significant increases
in smoking-adjusted relative lung cancer risk associated with exposure
to diesel exhaust, of 1.33 to 1.47. These meta-analyses demonstrate the
effect of pooling many studies and in this case show the positive
relationship between diesel exhaust exposure and lung cancer

across a variety of diesel exhaust-exposed occupations.48 49
---------------------------------------------------------------------------

    \48\ Bhatia, R., Lopipero, P., Smith, A. (1998) Diesel exposure
and lung cancer. Epidemiology 9(1):84-91.
    \49\ Lipsett, M; Campleman, S; (1999) Occupational exposure to
diesel exhaust and lung cancer: a meta-analysis. Am J Public Health
80(7): 1009-1017.
---------------------------------------------------------------------------

    In the absence of a cancer unit risk, the Diesel HAD sought to
provide additional insight into the significance of the diesel exhaust-
cancer hazard by estimating possible ranges of risk that might be
present in the population. An exploratory analysis was used to
characterize a possible risk range by comparing a typical environmental
exposure level for highway diesel sources to a selected range of
occupational exposure levels. The occupationally observed risks were
then proportionally scaled according to the exposure ratios to obtain
an estimate of the possible environmental risk. A number of
calculations are needed to accomplish this, and these can be seen in
the EPA Diesel HAD. The outcome was that environmental risks from
diesel exhaust exposure could range from a low of 10-4 to
10-5 to as high as 10-3, reflecting the range of
occupational exposures that could be associated with the relative and
absolute risk levels observed in the occupational studies. Because of
uncertainties, the analysis acknowledged that the risks could be lower
than 10-4 or 10-5, and a zero risk from diesel
exhaust exposure was not ruled out.
    Retrospective health studies of railroad workers have played an
important part in determining that exposure to diesel exhaust is likely
to be carcinogenic to humans by inhalation from environmental
exposures. Key evidence of the diesel exhaust exposure linkage to lung
cancer comes from two retrospective case-control studies of railroad
workers which are discussed at length in the Diesel HAD and summarized
in Chapter 2 of the RIA.
(ii) Diesel Exhaust: Other Health Effects
    Noncancer health effects of acute and chronic exposure to diesel
exhaust emissions are also of concern to the EPA. EPA derived a diesel
exhaust reference concentration (RfC) from consideration of four well-
conducted chronic rat inhalation studies showing adverse pulmonary
effects.50 51 52 53 The RfC is 5 [mu]g/m3 for
diesel exhaust as measured by diesel PM. This RfC does not consider
allergenic effects such as those associated with asthma or immunologic
effects. There is growing evidence, discussed in the Diesel HAD, that
exposure to diesel exhaust can exacerbate these effects, but the
exposure-response data are presently lacking to derive an RfC. The EPA
Diesel HAD states, ``With DPM [diesel particulate matter] being a
ubiquitous component of ambient PM, there is an uncertainty about the
adequacy of the existing DE [diesel exhaust] noncancer database to
identify all of the pertinent DE-caused noncancer health hazards.'' (p.
9-19). The Diesel HAD concludes ``that acute exposure to DE [diesel
exhaust] has been associated with irritation of the eye, nose, and
throat, respiratory symptoms (cough and phlegm), and neurophysiological
symptoms such as headache, lightheadedness, nausea, vomiting, and
numbness or tingling of the extremities.'' \54\
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    \50\ Ishinishi, N; Kuwabara, N; Takaki, Y; et al. (1988) Long-
term inhalation experiments on diesel exhaust. In: Diesel exhaust
and health risks. Results of the HERP studies. Ibaraki, Japan:
Research Committee for HERP Studies; pp. 11-84.
    \51\ Heinrich, U; Fuhst, R; Rittinghausen, S; et al. (1995)
Chronic inhalation exposure of Wistar rats and two different strains
of mice to diesel engine exhaust, carbon black, and titanium
dioxide. Inhal. Toxicol. 7:553-556.
    \52\ Mauderly, JL; Jones, RK; Griffith, WC; et al. (1987) Diesel
exhaust is a pulmonary carcinogen in rats exposed chronically by
inhalation. Fundam. Appl. Toxicol. 9:208-221.
    \53\ Nikula, KJ; Snipes, MB; Barr, EB; et al. (1995) Comparative
pulmonary toxicities and carcinogenicities of chronically inhaled
diesel exhaust and carbon black in F344 rats. Fundam. Appl. Toxicol.
25:80-94.
    \54\ ``Health Assessment Document for Diesel Engine Exhaust,''
U.S. Environmental Protection Agency, 600/8-90/057F, http://
www.epa.gov/ttn/atw/dieselfinal.pdf, May 2002, p. 9-9.
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    Exposure to diesel exhaust has also been shown to cause serious
noncancer effects in occupational exposure studies. One study of
railroad workers and electricians, cited in the Diesel HAD,\55\ found
that exposure to diesel exhaust resulted in neurobehavioral impairments
in one or more areas including reaction time, balance, blink reflex
latency, verbal recall, and color vision confusion indices. Pulmonary
function tests also showed that 10 of the 16 workers had airway
obstruction and another group of 10 of 16 workers had chronic
bronchitis, chest pain, tightness, and hyperactive airways. Finally, a
variety of studies have been published subsequent to the completion of
the Diesel HAD. One such study, published in 2006,\56\ found that
railroad engineers and conductors with diesel exhaust exposure from
operating trains had an increased incidence of chronic obstructive
pulmonary disease (COPD) mortality. The odds of COPD mortality
increased with years on the job so that those who had worked more than
16 years as an engineer or conductor after 1959 had an increased risk
of 1.61 (95% confidence interval, 1.12-2.30). EPA is assessing the
significance of this study within the context of the broader
literature.
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    \55\ Kilburn (2000) See HAD Chapter 5-7.
    \56\ Hart, JE; Laden F; Schenker, M.B.; and Garshick, E. Chronic
Obstructive Pulmonary Disease Mortality in Diesel-Exposed Railroad
Workers; Environmental Health Perspective July 2006: 1013-1016.
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(iii) Ambient PM2.5 Levels and Exposure to Diesel Exhaust PM
    The Diesel HAD also briefly summarizes health effects associated
with ambient PM and discusses the EPA's annual PM2.5 NAAQS
of 15 [mu]g/m\3\. There is a much more extensive body of human data
showing a wide spectrum of adverse health effects associated with
exposure to ambient PM, of which diesel exhaust is an important
component. The PM2.5 NAAQS is designed to provide protection from the
noncancer and premature mortality effects of PM2.5 as a whole.
(iv) Diesel Exhaust PM Exposures
    Exposure of people to diesel exhaust depends on their various
activities, the time spent in those activities, the locations where
these activities occur, and the levels of diesel exhaust pollutants in
those locations. The major difference between ambient levels of diesel
particulate and exposure levels for diesel particulate is that exposure
accounts for a person moving from location to location, proximity to
the emission source, and whether the exposure occurs in an enclosed
environment.

Occupational Exposures

    Occupational exposures to diesel exhaust from mobile sources,
including locomotive engines and marine diesel engines, can be several
orders of magnitude greater than typical exposures in the non-
occupationally exposed population.
    Over the years, diesel particulate exposures have been measured for
a number of occupational groups. A wide range of exposures have been
reported, from 2 [mu]g/m3 to 1,280 [mu]g/m3, for
a variety of occupations. Studies have shown that miners and railroad
workers typically have higher diesel exposure levels than other
occupational groups studied, including firefighters, truck dock
workers, and truck drivers (both short and long haul).\57\ As discussed
in the Diesel HAD, the National Institute of Occupational Safety and
Health

(NIOSH) has estimated a total of 1,400,000 workers are occupationally
exposed to diesel exhaust from on-road and nonroad vehicles including
locomotive and marine diesel engines.
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    \57\ Diesel HAD Page 2-110, 8-12; Woskie, SR; Smith, TJ;
Hammond, SK: et al. (1988a) Estimation of the DE exposures of
railroad workers: II. National and historical exposures. Am J Ind
Med 12:381-394.
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Elevated Concentrations and Ambient Exposures in Mobile Source-Impacted
Areas

    Regions immediately downwind of rail yards and marine ports may
experience elevated ambient concentrations of directly-emitted
PM2.5 from diesel engines. Due to the unique nature of rail
yards and marine ports, emissions from a large number of diesel engines
are concentrated in a small area. Furthermore, emissions occur at or
near ground level, allowing emissions of diesel engines to reach nearby
receptors without fully mixing with background air.
    A 2004 study conducted by the California Air Resources Board (CARB)
examined the air quality impacts of railroad operations at the J.R.
Davis Rail Yard, the largest service and maintenance rail facility in
the western United States.\58\ The yard occupies 950 acres along a one-
quarter mile wide and four-mile long section of land in Roseville, CA.
The study developed an emissions inventory for the facility for the
year 2000 and modeled ambient concentrations of diesel PM using a well-
accepted dispersion model (ISCST3). The study estimated substantially
elevated diesel PM concentrations in an area 5,000 meters from the
facility, with higher concentrations closer to the rail yard. Using
local meteorological data, annual average contributions from the rail
yard to ambient diesel PM concentrations under prevailing wind
conditions were 1.74, 1.18, 0.80, and 0.25 [mu]g/m3 at
receptors located 200, 500, 1000, and 5000 meters from the yard,
respectively. Several tens of thousands of people live within the area
estimated to experience substantial increases in annual average ambient
PM2.5 as a result of these rail yard emissions.
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    \58\ Hand, R.; Pingkuan, D.; Servin, A.; Hunsaker, L.; Suer, C.
(2004) Roseville rail yard study. California Air Resources Board.
[Online at http://www.arb.ca.gov/diesel/documents/rrstudy.htm] This
document can be found in Docket EPA-HQ-OAR-2003-0190.
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    Another study from CARB evaluated air quality impacts of diesel
engine emissions within the Ports of Long Beach and Los Angeles in
California, one of the largest ports in the U.S.\59\ Like the earlier
rail yard study, the port study employed the ISCST3 dispersion model.
Using local meteorological data, annual average concentrations were
substantially elevated over an area exceeding 200,000 acres. Because
the ports are located near heavily-populated areas, the modeling
indicated that over 700,000 people lived in areas with at least 0.3
[mu]g/m\3\ of port-related diesel PM in ambient air, about 360,000
people lived in areas with at least 0.6 [mu]g/m3 of diesel
PM, and about 50,000 people lived in areas with at least 1.5 ug/
m3 of ambient diesel PM directly from the port. Most
recently, CARB released several additional Railyard Health Risk
Assessments which all show that diesel PM emissions result in
significantly higher pollution risks in nearby communities.\60\
Together these studies highlight the substantial contribution these
facilities make to elevated ambient concentrations in populated areas.
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    \59\ State of California Air Resources Board. Diesel Particulate
Matter Exposure Assessment Study for the Ports of Los Angeles and
Long Beach, April 2006. This document is available in Docket EPA-HQ-
OAR-2003-0190. This document is available electronically at: ftp://
ftp.arb.ca.gov/carbis/msprog/offroad/marinevess/documents/
portstudy0406.pdf.
    \60\ These studies are available in Docket EPA-HQ-OAR-2003-0190.
Studies are also available at http://www.arb.ca.gov/railyard/hra/
hra.htm.
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    As mentioned in section II.A of this preamble, EPA recently
conducted an initial screening-level analysis of a representative
selection of national marine port areas and rail yards to begin to
better understand the populations that are exposed to DPM emissions
from these facilities.61 62 As part of this study, a
computer geographic information system (GIS) was used to identify the
locations and property boundaries of 47 marine ports and 37 rail yard
facilities.\63\ Census information was used to estimate the size and
demographic characteristics of the population living in the vicinity of
the ports and rail yards. The results indicate that at least 13 million
people, including a disproportionate number of low-income, African-
Americans, and Hispanics, live in the vicinity of these facilities and
are being exposed to ambient DPM levels that are 2.0 [mu]g/
m3 and 0.2 [mu]g/m3 above levels found in areas
further from these facilities. These populations will benefit from the
controls being finalized in this action. This study is discussed in
greater detail in chapter 2 of the RIA and detailed findings of this
study are available in the public docket for this rulemaking.
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    \61\ ICF International. September 28, 2007. Estimation of diesel
particulate matter concentration isopleths for marine harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \62\ ICF International. September 28, 2007. Estimation of diesel
particulate matter population exposure near selected harbor areas
and rail yards. Memorandum to EPA under Work Assignment Number 0-3,
Contract Number EP-C-06-094. This memo is available in Docket EPA-
HQ-OAR-2003-0190.
    \63\ The Agency selected a representative sample of the top 150
U.S. ports including coastal, inland, and Great Lake ports. In
selecting a sample of rail yards the Agency identified a subset from
the hundreds of rail yards operated by Class I Railroads.
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(b) Other Air Toxics--benzene, 1,3-butadiene, formaldehyde,
acetaldehyde, acrolein, POM, naphthalene
    Locomotive and marine diesel engine exhaust emissions also
contribute to ambient levels of other air toxics known or suspected as
human or animal carcinogens, or that have noncancer health effects.
These other air toxics include benzene, 1,3-butadiene, formaldehyde,
acetaldehyde, acrolein, polycyclic organic matter (POM), and
naphthalene. All of these compounds, except acetaldehyde, were
identified as national or regional cancer risk or noncancer hazard
drivers in the 1999 National-Scale Air Toxics Assessment (NATA) and
have significant inventory contributions from mobile sources. That is,
for a significant portion of the population, these compounds pose a
significant portion of the total cancer and noncancer risk from
breathing outdoor air toxics. The reductions in locomotive and marine
diesel engine emissions finalized in this rulemaking will help reduce
exposure to these harmful substances.
    Benzene: EPA has characterized benzene as a known human carcinogen
(causing leukemia) by all routes of exposure, and concludes that
exposure is associated with additional health effects, including
genetic changes in both humans and animals and increased proliferation
of bone marrow cells in mice.64 65 66 EPA states in its IRIS
database that data indicate a causal relationship between benzene
exposure and acute lymphocytic leukemia and suggests a relationship
between benzene exposure and chronic non-lymphocytic leukemia and
chronic lymphocytic leukemia. The IARC has determined that benzene is a
human carcinogen and the U.S. DHHS has characterized

benzene as a known human carcinogen.67 68
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    \64\ U.S. EPA. 2000. Integrated Risk Information System File for
Benzene. This material is available electronically at http://
www.epa.gov/iris/subst/0276.htm.
    \65\ International Agency for Research on Cancer (IARC). 1982.
Monographs on the evaluation of carcinogenic risk of chemicals to
humans, Volume 29, Some industrial chemicals and dyestuffs, World
Health Organization, Lyon, France, p. 345-389.
    \66\ Irons, R.D.; Stillman, W.S.; Colagiovanni, D.B.; Henry,
V.A. 1992. Synergistic action of the benzene metabolite hydroquinone
on myelopoietic stimulating activity of granulocyte/macrophage
colony-stimulating factor in vitro, Proc. Natl. Acad. Sci. 89:3691-
3695.
    \67\ International Agency for Research on Cancer (IARC). 1987.
Monographs on the evaluation of carcinogenic risk of chemicals to
humans, Volume 29, Supplement 7, Some industrial chemicals and
dyestuffs, World Health Organization, Lyon, France.
    \68\ U.S. Department of Health and Human Services National
Toxicology Program 11th Report on Carcinogens available at: http://
ntp.niehs.nih.gov/go/16183.
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    A number of adverse noncancer health effects including blood
disorders, such as preleukemia and aplastic anemia, have also been
associated with long-term exposure to benzene.69 70 The most
sensitive noncancer effect observed in humans, based on current data,
is the depression of the absolute lymphocyte count in
blood.71 72 In addition, recent work, including studies
sponsored by the Health Effects Institute (HEI), provides evidence that
biochemical responses are occurring at lower levels of benzene exposure
than previously known.73, 74, 75, 76 EPA's IRIS program has
not yet evaluated these new data.
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    \69\ Aksoy, M. (1989). Hematotoxicity and carcinogenicity of
benzene. Environ. Health Perspect. 82: 193-197.
    \70\ Goldstein, B.D. (1988). Benzene toxicity. Occupational
medicine. State of the Art Reviews. 3: 541-554.
    \71\ Rothman, N., G.L. Li, M. Dosemeci, W.E. Bechtold, G.E.
Marti, Y.Z. Wang, M. Linet, L.Q. Xi, W. Lu, M.T. Smith, N. Titenko-
Holland, L.P. Zhang, W. Blot, S.N. Yin, and R.B. Hayes (1996)
Hematotoxicity among Chinese workers heavily exposed to benzene. Am.
J. Ind. Med. 29: 236-246.
    \72\ U.S. EPA (2002) Toxicological Review of Benzene (Noncancer
Effects). Environmental Protection Agency, Integrated Risk
Information System (IRIS), Research and Development, National Center
for Environmental Assessment, Washington DC. This material is
available electronically at http://www.epa.gov/iris/subst/0276.htm.
    \73\ Qu, O.; Shore, R.; Li, G.; Jin, X.; Chen, C.L.; Cohen, B.;
Melikian, A.; Eastmond, D.; Rappaport, S.; Li, H.; Rupa, D.;
Suramaya, R.; Songnian, W.; Huifant, Y.; Meng, M.; Winnik, M.; Kwok,
E.; Li, Y.; Mu, R.; Xu, B.; Zhang, X.; Li, K. (2003) HEI Report 115,
Validation & Evaluation of Biomarkers in Workers Exposed to Benzene
in China.
    \74\ Qu, Q., R. Shore, G. Li, X. Jin, L.C. Chen, B. Cohen, et
al. (2002) Hematological changes among Chinese workers with a broad
range of benzene exposures. Am. J. Industr. Med. 42: 275-285.
    \75\ Lan, Qing, Zhang, L., Li, G., Vermeulen, R., et al. (2004)
Hematotoxically in Workers Exposed to Low Levels of Benzene. Science
306: 1774-1776.
    \76\ Turtletaub, K.W. and Mani, C. (2003) Benzene metabolism in
rodents at doses relevant to human exposure from Urban Air. Research
Reports Health Effect Inst. Report No.113.
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    1,3-Butadiene: EPA has characterized 1,3-butadiene as carcinogenic
to humans by inhalation.77 78 The IARC has determined that
1, 3-butadiene is a human carcinogen and the U.S. DHHS has
characterized 1,3-butadiene as a known human
carcinogen.79 80 There are numerous studies consistently
demonstrating that 1,3-butadiene is metabolized into genotoxic
metabolites by experimental animals and humans. The specific mechanisms
of 1,3-butadiene-induced carcinogenesis are unknown; however, the
scientific evidence strongly suggests that the carcinogenic effects are
mediated by genotoxic metabolites. Animal data suggest that females may
be more sensitive than males for cancer effects associated with 1,3-
butadiene exposure; while there are insufficient data in humans from
which to draw conclusions about sensitive subpopulations.
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    \77\ U.S. EPA (2002) Health Assessment of 1,3-Butadiene. Office
of Research and Development, National Center for Environmental
Assessment, Washington Office, Washington, DC. Report No. EPA600-P-
98-001F. This document is available electronically at http://
www.epa.gov/iris/supdocs/buta-sup.pdf.
    \78\ U.S. EPA (2002) Full IRIS Summary for 1,3-butadiene (CASRN
106-99-0). Environmental Protection Agency, Integrated Risk
Information System (IRIS), Research and Development, National Center
for Environmental Assessment, Washington, DC http://www.epa.gov/
iris/subst/0139.htm.
    \79\ International Agency for Research on Cancer (IARC) (1999)
Monographs on the evaluation of carcinogenic risk of chemicals to
humans, Volume 71, Re-evaluation of some organic chemicals,
hydrazine and hydrogen peroxide and Volume 97 (in preparation),
World Health Organization, Lyon, France.
    \80\ U.S. Department of Health and Human Services (2005)
National Toxicology Program 11th Report on Carcinogens available at:
ntp.niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-975E-
7FCE50709CB4C932.
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    1,3-Butadiene also causes a variety of reproductive and
developmental effects in mice; no human data on these effects are
available. The most sensitive effect was ovarian atrophy observed in a
lifetime bioassay of female mice.\81\
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    \81\ Bevan, C.; Stadler, J.C.; Elliot, G.S.; et al. (1996)
Subchronic toxicity of 4-vinylcyclohexene in rats and mice by
inhalation. Fundam. Appl. Toxicol. 32:1-10.
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    Formaldehyde: Since 1987, EPA has classified formaldehyde as a
probable human carcinogen based on evidence in humans and in rats,
mice, hamsters, and monkeys.\82\ EPA is currently reviewing recently
published epidemiological data. For instance, research conducted by the
National Cancer Institute (NCI) found an increased risk of
nasopharyngeal cancer and lymphohematopoietic malignancies such as
leukemia among workers exposed to formaldehyde.83 84 NCI is
currently updating these studies. A recent National Institute of
Occupational Safety and Health (NIOSH) study of garment workers also
found increased risk of death due to leukemia among workers exposed to
formaldehyde.\85\ Extended follow-up of a cohort of British chemical
workers did not find evidence of an increase in nasopharyngeal or
lymphohematopoietic cancers, but a continuing statistically significant
excess in lung cancers was reported.\86\ Recently, the IARC re-
classified formaldehyde as a human carcinogen (Group 1).\87\
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    \82\ U.S. EPA (1987) Assessment of Health Risks to Garment
Workers and Certain Home Residents from Exposure to Formaldehyde,
Office of Pesticides and Toxic Substances, April 1987.
    \83\ Hauptmann, M.; Lubin, J.H.; Stewart, P.A.; Hayes, R.B.;
Blair, A. 2003. Mortality from lymphohematopoetic malignancies among
workers in formaldehyde industries. Journal of the National Cancer
Institute 95: 1615-1623.
    \84\ Hauptmann, M.; Lubin, J.H.; Stewart, P.A.; Hayes, R.B.;
Blair, A. 2004. Mortality from solid cancers among workers in
formaldehyde industries. American Journal of Epidemiology 159: 1117-
1130.
    \85\ Pinkerton, L.E. 2004. Mortality among a cohort of garment
workers exposed to formaldehyde: an update. Occup. Environ. Med. 61:
193-200.
    \86\ Coggon, D, EC Harris, J Poole, KT Palmer. 2003. Extended
follow-up of a cohort of British chemical workers exposed to
formaldehyde. J National Cancer Inst. 95:1608-1615.
    \87\ International Agency for Research on Cancer (IARC). 2006.
Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. Volume
88. (in preparation), World Health Organization, Lyon, France.
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    Formaldehyde exposure also causes a range of noncancer health
effects, including irritation of the eyes (burning and watering of the
eyes), nose and throat. Decreased pulmonary function has been observed
in humans. Effects from repeated exposure in humans include respiratory
tract irritation, chronic bronchitis and nasal epithelial lesions.\88\
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