\88\ U.S. Department of Health and Human Services Agency for
Toxic Substances and Disease Registry. 1999. Toxicological Profile
for formaldehyde. Available at http://www.atsdr.cdc.gov/toxprofiles/
tp111.html.
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    Acetaldehyde: EPA has characterized acetaldehyde as a probable
human carcinogen, based on nasal tumors in rats.\89\ Acetaldehyde is
reasonably anticipated to be a human carcinogen by the U.S. Department
of Health and Human Services (DHHS) in the 11th Report on Carcinogens
and is classified as possibly carcinogenic to humans (Group 2B) by the
International Agency for Research on Carcinogens
(IARC).90 91 EPA is currently conducting a reassessment of
cancer and noncancer risk from inhalation exposure to acetaldehyde.
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    \89\ U.S. EPA. 1991. Integrated Risk Information System File of
Acetaldehyde. Research and Development, National Center for
Environmental Assessment, Washington, DC. This material is available
electronically at http://www.epa.gov/iris/subst/0290.htm.
    \90\ U.S. Department of Health and Human Services National
Toxicology Program 11th Report on Carcinogens available at:
ntp.niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-975E-
7FCE50709CB4C932.
    \91\ International Agency for Research on Cancer (IARC). 1999.
Re-evaluation of some organic chemicals, hydrazine, and hydrogen
peroxide. IARC Monographs on the Evaluation of Carcinogenic Risk of
Chemical to Humans, Vol 71. Lyon, France.

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    The primary noncancer effects of exposure to acetaldehyde vapors
include irritation of the eyes, skin, and respiratory tract.\92\ In
short-term (4 week) rat studies, compound-related histopathological
changes were observed only in the respiratory system at various
concentration levels of exposure.93 94 Data from these
studies were used by EPA to develop an inhalation reference
concentration. Some asthmatics have been shown to be a sensitive
subpopulation to decrements in functional expiratory volume (FEV1 test)
and bronchoconstriction upon acetaldehyde inhalation.\95\
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    \92\ U.S. EPA. 1991. Integrated Risk Information System File of
Acetaldehyde. This material is available electronically at http://
www.epa.gov/iris/subst/0290.htm.
    \93\ Appleman, L.M., R.A. Woutersen, V.J. Feron, R.N. Hooftman,
and W.R.F. Notten. 1986. Effects of the variable versus fixed
exposure levels on the toxicity of acetaldehyde in rats. J. Appl.
Toxicol. 6: 331-336.
    \94\ Appleman, L.M., R.A. Woutersen, and V.J. Feron. 1982.
Inhalation toxicity of acetaldehyde in rats. I. Acute and subacute
studies. Toxicology. 23: 293-297.
    \95\ Myou, S.; Fujimura, M.; Nishi K.; Ohka, T.; and Matsuda, T.
1993. Aerosolized acetaldehyde induces histamine-mediated
bronchoconstriction in asthmatics. Am. Rev. Respir. Dis. 148(4 Pt
1): 940-3.
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    Acrolein: Acrolein is extremely acrid and irritating to humans when
inhaled, with acute exposure resulting in upper respiratory tract
irritation, mucus hypersecretion and congestion. Levels considerably
lower than 1 ppm (2.3 mg/m3) elicit subjective complaints of
eye and nasal irritation and a decrease in the respiratory
rate.96 97 Lesions to the lungs and upper respiratory tract
of rats, rabbits, and hamsters have been observed after subchronic
exposure to acrolein. Based on animal data, individuals with
compromised respiratory function (e.g., emphysema, asthma) are expected
to be at increased risk of developing adverse responses to strong
respiratory irritants such as acrolein. This was demonstrated in mice
with allergic airway-disease by comparison to non-diseased mice in a
study of the acute respiratory irritant effects of acrolein.\98\ EPA is
currently in the process of conducting an assessment of acute exposure
effects for acrolein. The intense irritancy of this carbonyl has been
demonstrated during controlled tests in human subjects who suffer
intolerable eye and nasal mucosal sensory reactions within minutes of
exposure.\99\
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    \96\ Weber-Tschopp, A; Fischer, T; Gierer, R; et al. (1977)
Experimentelle reizwirkungen von Acrolein auf den Menschen. Int Arch
Occup Environ Hlth. 40(2):117-130. In German.
    \97\ Sim, VM; Pattle, RE. (1957) Effect of possible smog
irritants on human subjects. J Am Med Assoc. 165(15):1908-1913.
    \98\ Morris JB, Symanowicz PT, Olsen JE, et al. 2003. Immediate
sensory nerve-mediated respiratory responses to irritants in healthy
and allergic airway-diseased mice. J Appl Physiol. 94(4):1563-1571.
    \99\ Sim VM, Pattle RE. Effect of possible smog irritants on
human subjects. JAMA. 165: 1980-2010, 1957.
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    EPA determined in 2003 that the human carcinogenic potential of
acrolein could not be determined because the available data were
inadequate. No information was available on the carcinogenic effects of
acrolein in humans and the animal data provided inadequate evidence of
carcinogenicity.\100\ The IARC determined in 1995 that acrolein was not
classifiable as to its carcinogenicity in humans.\101\
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    \100\ U.S. EPA. (2003). Integrated Risk Information System File
of Acrolein. Research and Development, National Center for
Environmental Assessment, Washington, DC. This material is available
at http://www.epa.gov/iris/subst/0364.htm.
    \101\ International Agency for Research on Cancer (IARC). 1995.
Monographs on the evaluation of carcinogenic risk of chemicals to
humans, Volume 63, Dry cleaning, some chlorinated solvents and other
industrial chemicals, World Health Organization, Lyon, France.
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    Polycyclic Organic Matter (POM): POM is generally defined as a
large class of organic compounds which have multiple benzene rings and
a boiling point greater than 100 degrees Celsius. Many of the compounds
included in the class of compounds known as POM are classified by EPA
as probable human carcinogens based on animal data. One of these
compounds, naphthalene, is discussed separately below. Polycyclic
aromatic hydrocarbons (PAHs) are a subset of POM that contain only
hydrogen and carbon atoms. A number of PAHs are known or suspected
carcinogens. Recent studies have found that maternal exposures to PAHs
(a subclass of POM) in a population of pregnant women were associated
with several adverse birth outcomes, including low birth weight and
reduced length at birth, as well as impaired cognitive development at
age three.102 103 EPA has not yet evaluated these recent
studies.
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    \102\ Perera, F.P.; Rauh, V.; Tsai, W-Y.; et al. (2002) Effect
of transplacental exposure to environmental pollutants on birth
outcomes in a multiethnic population. Environ Health Perspect. 111:
201-205.
    \103\ Perera, F.P.; Rauh, V.; Whyatt, R.M.; Tsai, W.Y.; Tang,
D.; Diaz, D.; Hoepner, L.; Barr, D.; Tu, Y.H.; Camann, D.; Kinney,
P. (2006) Effect of prenatal exposure to airborne polycyclic
aromatic hydrocarbons on neurodevelopment in the first 3 years of
life among inner-city children. Environ Health Perspect. 114: 1287-
1292.
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    Naphthalene: Naphthalene is found in small quantities in gasoline
and diesel fuels but is primarily a product of combustion. EPA recently
released an external review draft of a reassessment of the inhalation
carcinogenicity of naphthalene.\104\ The draft reassessment recently
completed external peer review.\105\ Based on external peer review
comments received to date, additional analyses are being undertaken.
This external review draft does not represent official agency opinion
and was released solely for the purposes of external peer review and
public comment. Once EPA evaluates public and peer reviewer comments,
the document will be revised. The National Toxicology Program listed
naphthalene as ``reasonably anticipated to be a human carcinogen'' in
2004 on the basis of bioassays reporting clear evidence of
carcinogenicity in rats and some evidence of carcinogenicity in
mice.\106\ California EPA has released a new risk assessment for
naphthalene, and the IARC has reevaluated naphthalene and re-classified
it as Group 2B: Possibly carcinogenic to humans.\107\ Naphthalene also
causes a number of chronic non-cancer effects in animals, including
abnormal cell changes and growth in respiratory and nasal tissues.\108\
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    \104\ U.S. EPA (2004) Toxicological Review of Naphthalene
(Reassessment of the Inhalation Cancer Risk), Environmental
Protection Agency, Integrated Risk Information System, Research and
Development, National Center for Environmental Assessment,
Washington, DC. This material is available electronically at http://
www.epa.gov/iris/subst/0436.htm.
    \105\ Oak Ridge Institute for Science and Education (2004)
External Peer Review for the IRIS Reassessment of the Inhalation
Carcinogenicity of Naphthalene. August 2004. http://cfpub.epa.gov/
ncea/cfm/recordisplay.cfm?deid=84403.
    \106\ National Toxicology Program (NTP). (2004). 11th Report on
Carcinogens. Public Health Service, U.S. Department of Health and
Human Services, Research Triangle Park, NC. Available from: http://
ntp-server.niehs.nih.gov.
    \107\ International Agency for Research on Cancer (IARC) (2002)
Monographs on the Evaluation of the Carcinogenic Risk of Chemicals
for Humans. Vol. 82. Lyon, France.
    \108\ U.S. EPA (1998) Toxicological Review of Naphthalene,
Environmental Protection Agency, Integrated Risk Information System,
Research and Development, National Center for Environmental
Assessment, Washington, DC. This material is available
electronically at http://www.epa.gov/iris/subst/0436.htm.
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C. Environmental Impacts

    There are a number of public welfare effects associated with the
presence of ozone, NOX and PM2.5 in the ambient
air. In this section we discuss visibility, the impact of deposition on
ecosystems and materials, and the impact of ozone on plants, including
trees, agronomic crops and urban ornamentals.
(1) Visibility
    Visibility can be defined as the degree to which the atmosphere is
transparent to visible light. Airborne particles degrade visibility by
scattering and

absorbing light. Visibility is important because it has direct
significance to people's enjoyment of daily activities in all parts of
the country. Individuals value good visibility for the well-being it
provides them directly, where they live and work and in places where
they enjoy recreational opportunities. Visibility is also highly valued
in significant natural areas such as national parks and wilderness
areas and special emphasis is given to protecting visibility in these
areas. For more information on visibility, see the final 2004 PM AQCD
as well as the 2005 PM Staff Paper.109 110>
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    \109\ 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.
    \110\ 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.
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    EPA is pursuing a two-part strategy to address visibility. First,
to address the welfare effects of PM on visibility, EPA has set
secondary PM2.5 standards which act in conjunction with the
establishment of a regional haze program. In setting this secondary
standard, EPA has concluded that PM2.5 causes adverse effects on
visibility in various locations, depending on PM concentrations and
factors such as chemical composition and average relative humidity.
Second, section 169 of the Clean Air Act provides additional authority
to address existing visibility impairment and prevent future visibility
impairment in the 156 national parks, forests and wilderness areas
categorized as mandatory class I federal areas (62 FR 38680-81, July
18, 1997).\111\ In July 1999, the regional haze rule (64 FR 35714) was
put in place to protect the visibility in mandatory class I federal
areas. Visibility can be said to be impaired in both PM2.5
nonattainment areas and mandatory class I federal areas.
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    \111\ These areas are defined in section 162 of the Act as those
national parks exceeding 6,000 acres, wilderness areas and memorial
parks exceeding 5,000 acres, and all international parks which were
in existence on August 7, 1977.
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    Locomotives and marine engines contribute to visibility concerns in
these areas through their primary PM2.5 emissions and their
NOX emissions which contribute to the formation of secondary
PM2.5.
Current Visibility Impairment
    As of October 10, 2007, almost 90 million people live in
nonattainment areas for the 1997 PM2.5 NAAQS. These populations, as
well as large numbers of individuals who travel to these areas, are
likely to experience visibility impairment. In addition, while
visibility trends have improved in mandatory class I federal areas the
most recent data show that these areas continue to suffer from
visibility impairment.\112\ In summary, visibility impairment is
experienced throughout the U.S., in multi-state regions, urban areas,
and remote mandatory class I federal areas.113 114
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    \112\ U.S. EPA (2002). Latest Findings on National Air Quality--
2002 Status and Trends. EPA 454/K-03-001.
    \113\ U.S. EPA. Air Quality Designations and Classifications for
the Fine Particles (PM2.5) National Ambient Air Quality Standards,
December 17, 2004. (70 FR 943, Jan 5, 2005) This document is also
available on the Web at: http://www.epa.gov/pmdesignations/.
    \114\ U.S. EPA. Regional Haze Regulations, July 1, 1999. (64 FR
35714, July 1, 1999).
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Future Visibility Impairment
    Air quality modeling conducted for this final rule was used to
project visibility conditions in 133 mandatory class I federal areas
across the U.S. in 2020 and 2030. The results indicate that improvement
in visibility will occur in all mandatory class I federal areas
although all areas will continue to have annual average deciview levels
above background in 2020 and 2030. Chapter 2 of the RIA contains more
detail on the visibility portion of the air quality modeling.
(2) Plant and Ecosystem Effects of Ozone
    Elevated ozone levels contribute to environmental effects, with
impacts to plants and ecosystems being of most concern. Ozone can
produce both acute and chronic injury in sensitive species depending on
the concentration level and the duration of the exposure. Ozone effects
also tend to accumulate over the growing season of the plant, so that
even low concentrations experienced for a longer duration have the
potential to create chronic stress on vegetation. Ozone damage to
plants includes visible injury to leaves and a reduction in food
production through impaired photosynthesis, both of which can lead to
reduced crop yields, forestry production, and use of sensitive
ornamentals in landscaping. In addition, the reduced food production in
plants and subsequent reduced root growth and storage below ground, can
result in other, more subtle plant and ecosystems impacts. These
include increased susceptibility of plants to insect attack, disease,
harsh weather, interspecies competition and overall decreased plant
vigor. The adverse effects of ozone on forest and other natural
vegetation can potentially lead to species shifts and loss from the
affected ecosystems, resulting in a loss or reduction in associated
ecosystem goods and services. Lastly, visible ozone injury to leaves
can result in a loss of aesthetic value in areas of special scenic
significance like national parks and wilderness areas. The final 2006
Criteria Document presents more detailed information on ozone effects
on vegetation and ecosystems.
    As discussed above, locomotive and marine diesel engine emissions
of NOX contribute to ozone and therefore the NOX
standards will help reduce crop damage and stress on vegetation from
ozone.
(3) Atmospheric Deposition
    Wet and dry deposition of ambient particulate matter delivers a
complex mixture of metals (e.g., mercury, zinc, lead, nickel, aluminum,
cadmium), organic compounds (e.g., POM, dioxins, furans) and inorganic
compounds (e.g., nitrate, sulfate) to terrestrial and aquatic
ecosystems. The chemical form of the compounds deposited is impacted by
a variety of factors including ambient conditions (e.g., temperature,
humidity, oxidant levels) and the sources of the material. Chemical and
physical transformations of the particulate compounds occur in the
atmosphere as well as the media onto which they deposit. These
transformations in turn influence the fate, bioavailability and
potential toxicity of these compounds. Atmospheric deposition has been
identified as a key component of the environmental and human health
hazard posed by several pollutants including mercury, dioxin and
PCBs.\115\
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    \115\ U.S. EPA (2000). Deposition of Air Pollutants to the Great
Waters: Third Report to Congress. Office of Air Quality Planning and
Standards. EPA-453/R-00-0005. This document is available in Docket
EPA-HQ-OAR-2003-0190.
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    Adverse impacts on water quality can occur when atmospheric
contaminants deposit to the water surface or when material deposited on
the land enters a water body through runoff. Potential impacts of
atmospheric deposition to water bodies include those related to both
nutrient and toxic inputs. Adverse effects to human health and welfare
can occur from the addition of excess particulate nitrate nutrient
enrichment, which contributes to toxic algae blooms and zones of
depleted oxygen, which can lead to fish kills, frequently in coastal
waters. Particles contaminated with heavy metals or other toxins may
lead to the ingestion of contaminated fish, ingestion of contaminated
water, damage to the marine ecology, and limited recreational uses.
Several

studies have been conducted in U.S. coastal waters and in the Great
Lakes Region in which the role of ambient PM deposition and runoff is
investigated.116 117 118 119 120
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    \116\ U.S. EPA (2004). National Coastal Condition Report II.
Office of Research and Development/ Office of Water. EPA-620/R-03/
002. This document is available in Docket EPA-HQ-OAR-2003-0190.
    \117\ Gao, Y., E.D. Nelson, M.P. Field, et al. 2002.
Characterization of atmospheric trace elements on PM2.5 particulate
matter over the New York-New Jersey harbor estuary. Atmos. Environ.
36: 1077-1086.
    \118\ Kim, G., N. Hussain, J.R. Scudlark, and T.M. Church. 2000.
Factors influencing the atmospheric depositional fluxes of stable
Pb, 210Pb, and 7Be into Chesapeake Bay. J. Atmos. Chem. 36: 65-79.
    \119\ Lu, R., R.P. Turco, K. Stolzenbach, et al. 2003. Dry
deposition of airborne trace metals on the Los Angeles Basin and
adjacent coastal waters. J. Geophys. Res. 108(D2, 4074): AAC 11-1 to
11-24.
    \120\ Marvin, C.H., M.N. Charlton, E.J. Reiner, et al. 2002.
Surficial sediment contamination in Lakes Erie and Ontario: A
comparative analysis. J. Great Lakes Res. 28(3): 437-450.
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    Adverse impacts on soil chemistry and plant life have been observed
for areas heavily impacted by atmospheric deposition of nutrients,
metals and acid species, resulting in species shifts, loss of
biodiversity, forest decline and damage to forest productivity.
Potential impacts also include adverse effects to human health through
ingestion of contaminated vegetation or livestock (as in the case for
dioxin deposition), reduction in crop yield, and limited use of land
due to contamination.
    The NOX, VOC and PM standards finalized in this action
will help reduce the environmental impacts of atmospheric deposition.
(4) Materials Damage and Soiling
    The deposition of airborne particles can reduce the aesthetic
appeal of buildings and culturally important articles through soiling,
and can contribute directly (or in conjunction with other pollutants)
to structural damage by means of corrosion or erosion.\121\ Particles
affect materials principally by promoting and accelerating the
corrosion of metals, by degrading paints, and by deteriorating building
materials such as concrete and limestone. Particles contribute to these
effects because of their electrolytic, hygroscopic, and acidic
properties, and their ability to adsorb corrosive gases (principally
sulfur dioxide). The rate of metal corrosion depends on a number of
factors, including the deposition rate and nature of the pollutant; the
influence of the metal protective corrosion film; the amount of
moisture present; variability in the electrochemical reactions; the
presence and concentration of other surface electrolytes; and the
orientation of the metal surface.
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    \121\ U.S. EPA (2005). Review of the National Ambient Air
Quality Standards for Particulate Matter: Policy Assessment of
Scientific and Technical Information, OAQPS Staff Paper. This
document is available in Docket EPA-HQ-OAR-2003-0190.
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    The PM2.5 standards finalized in this action will help reduce the
airborne particles that contribute to materials damage and soiling.

D. Other Criteria Pollutants Affected by This Final Rule

    Locomotive and marine diesel engines account for about 1 percent of
the mobile source carbon monoxide (CO) inventory. Carbon monoxide (CO)
is a colorless, odorless gas produced through the incomplete combustion
of carbon-based fuels. The current primary NAAQS for CO are 35 ppm for
the 1-hour average and 9 ppm for the 8-hour average. These values are
not to be exceeded more than once per year. As of October 10, 2007,
there are 854 thousand people living in 4 areas (made up of 5 counties)
that are designated as nonattainment for CO.
    Carbon monoxide enters the bloodstream through the lungs, forming
carboxyhemoglobin and reducing the delivery of oxygen to the body's
organs and tissues. The health threat from CO is most serious for those
who suffer from cardiovascular disease, particularly those with angina
or peripheral vascular disease. Healthy individuals also are affected,
but only at higher CO levels. Exposure to elevated CO levels is
associated with impairment of visual perception, work capacity, manual
dexterity, learning ability and performance of complex tasks. Carbon
monoxide also contributes to ozone nonattainment since carbon monoxide
reacts photochemically in the atmosphere to form ozone. Additional
information on CO related health effects can be found in the Air
Quality Criteria for Carbon Monoxide.\122\
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    \122\ U.S. EPA (2000). Air Quality Criteria for Carbon Monoxide,
EPA/600/P-99/001F. This document is available in Docket EPA-HQ-OAR-
2003-0190.
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E. Emissions from Locomotive and Marine Diesel Engines

(1) Overview
    The engine standards in this final rule will affect emissions of
PM2.5, NOX, VOCs, CO, and air toxics for
locomotive and marine diesel engines. Based on our analysis for this
rulemaking, we estimate that in 2001 locomotive and marine diesel
engines contributed almost 60,000 tons (18 percent) to the national
mobile source diesel PM2.5 inventory and about 2.0 million
tons (16 percent) to the mobile source NOX inventory. In
2030, absent the standards finalized today, these engines will
contribute about 50,000 tons (65 percent) to the mobile source diesel
PM2.5 inventory and almost 1.6 million tons (35 percent) to
the mobile source NOX inventory. Under today's final
standards, by 2030, annual NOX emissions from these engines
will be reduced by 800,000 tons, PM2.5 emissions by 27,000
tons, and VOC emissions by 43,000 tons.
    Locomotive and marine diesel engine emissions are expected to
continue to be a significant part of the mobile source emissions
inventory, both nationally and in ozone and PM2.5
nonattainment areas, in the coming years. Absent the standards
finalized today, we expect overall emissions from these engines to
decrease modestly over the next ten to fifteen years then remain
relatively flat through 2025 due to existing regulations such as lower
fuel sulfur requirements, the phase-in of locomotive and marine diesel
Tier 1 and Tier 2 engine standards, and the current Tier 0 locomotive
remanufacturing requirements. Starting after 2025, emission inventories
from these engines once again begin increasing due to growth in the
locomotive and marine sectors, see Table II-2.
    Each sub-section below discusses one of the affected pollutants,
including expected emissions reductions associated with the final
standards. Table II-2 summarizes the impacts of this rule for 2012,
2015, 2020, 2030 and 2040. Further details on our inventory estimates
are available in chapter 3 of the RIA.
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(2) PM2.5 Emission Reductions
    As described earlier, EPA believes that reductions of diesel
PM2.5 emissions are an important part of the nation's
progress toward clean air. PM2.5 reductions resulting from
this final rule will reduce hazardous air pollutants or air toxics from
these engines, reduce diesel exhaust exposure in communities near these
emissions sources, and help areas address visibility and other
environmental impacts associated with PM2.5 emissions.
    In 2001, annual emissions from locomotive and marine diesel engines
totaled about 60,000 tons (18 percent) of the national mobile source
diesel PM2.5 inventory and by 2030 these engines, absent
this final rule, contribute about 50,000 tons (65 percent) of the
mobile source diesel PM2.5 inventory. Both Table II-2 and
Figure II-2 show that PM2.5 emissions are relatively flat
through 2030 before beginning to rise again due to growth in these
sectors.
    Table II-2 and Figure II-2 present PM2.5 emission
reductions from locomotive and marine diesel engines with the final
standards required in this rule. Emissions of PM2.5 drop in
2012 and 2015 by 4,200 and 7,300 tons respectively. By 2020, annual
PM2.5 reductions total 14,500 tons and by 2030 emissions are
reduced further by 27,000 tons annually. Significant reductions from
these engines continue through 2040 when approximately 37,000 tons of
PM2.5 are annually eliminated as a result of this rule.
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BILLING CODE 6560-50-C
(3) NOX Emissions Reductions
    In 2001 annual emissions from locomotive and marine diesel engines
totaled about 2.0 million tons. Due to earlier engine standards for
these engines, annual NOX emissions drop to approximately
1.6 million tons in 2030. Both Table II-2 and Figure II-3 show
NOX emissions remaining fairly flat through 2030 before
beginning to rise again due to growth in these sectors.
    As shown in Table II-2 and Figure II-3, in the near term this rule
reduces annual NOX emissions from the current national
inventory baseline by 87,000 tons in 2012 and 161,000 tons in 2015. By
2020, annual NOX emissions are cut by 371,000 tons and by
2030--795,000 tons are eliminated. As with PM2.5 emissions,
a yearly decline in NOX emissions continues through 2040
when more than 1.1 million tons of NOX are annually reduced
from locomotive and marine diesel engines.
    These numbers are comparable to emission reductions projected in
2030 for our already established Clean Air Nonroad Diesel (CAND)
program. Table II-3 provides the 2030 NOX emission
reductions (and PM reductions) for this rule compared to the Heavy-Duty
Highway rule and CAND rule. The 2030 NOX reductions of about
738,000 tons for the CAND rule are slightly less than those from this
rule.
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   Table II-3.--Projected 2030 Emissions Reductions From Recent Mobile
                              Source Rules
                              [Short tons]
------------------------------------------------------------------------
                     Rule                           NOX         PM2.5
------------------------------------------------------------------------
Locomotive and Marine.........................      795,000       27,000
Clean Air Nonroad Diesel......................      738,000      129,000
Heavy-Duty Highway............................    2,600,000      109,000
------------------------------------------------------------------------

(4) Volatile Organic Compounds Emissions Reductions
    Emissions of volatile organic compounds (VOCs) from locomotive and
marine diesel engines are shown in Table II-2, along with the estimates
of the reductions we expect from the HC standard in our rule in 2012,
2015, 2020, 2030 and 2040. In 2012, 8,000 tons of VOCs are reduced and
in 2015 15,000 tons are annually eliminated from the inventory. By
2020, reductions will expand to 28,000 tons annually from these
engines. Over the next ten years, annual reductions from controlled
locomotive and marine diesel engines will produce annual VOC reductions
of 43,000 tons in 2030 and 55,000 tons in 2040. Figure II-4 shows our
estimate of VOC emissions between 2006 and 2040 both with and without
this rule.
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III. Emission Standards

    PM2.5This section details the emission standards,
implementation dates, and other major requirements of the new program.
Following brief summaries of the types of locomotives and marine
engines covered, we describe the provisions for:
     Standards for remanufactured Tier 0, 1, and 2 locomotives,
     Tier 3 and Tier 4 standards for newly-built line-haul
locomotives,
     Standards and other provisions for switch locomotives,
     Requirements to reduce idling locomotive emissions,
     Tier 3 and Tier 4 standards for newly-built marine diesel
engines, and
     Standards for remanufactured marine diesel engines.
    An assessment of the technological feasibility of the standards
follows the program description. To ensure that the benefits of the
standards are realized throughout the useful life of these engines, and
to incorporate lessons learned over the last few years from the
existing test and compliance programs, we are also revising test
procedures and related certification requirements, and adding
comparable provisions for remanufactured marine diesel engines. These
are described in section IV.

A. What Locomotives and Marine Engines Are Covered?

    The regulations being adopted affect locomotives currently
regulated under part 92 and marine diesel engines and vessels currently
regulated under parts 89, 1039, and 94, as described below.\123\ In
addition, they apply to existing marine diesel engines above 600 kW
(800 hp).
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    \123\ All of the regulatory parts referenced in this preamble
are parts in Title 40 of the Code of Federal Regulations, unless
otherwise noted.
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    With some exceptions, the locomotive regulations apply for all
locomotives originally built in or after 1973 that operate extensively
within the United States. See section IV.B for a discussion of the
exemption for locomotives that are used only incidentally within the
U.S. The exceptions include historic steam-powered locomotives and
locomotives powered solely by an external source of electricity. In
addition, the regulations generally do not apply to some existing
locomotives owned by small businesses. Furthermore, engines used in

locomotive-type vehicles with less than 750 kW (1006 hp) total power
(used primarily for railway maintenance), engines used only for hotel
power (for passenger railcar equipment), and engines that are used in
self-propelled passenger-carrying railcars, are excluded from these
regulations. The engines used in these smaller locomotive-type vehicles
are generally subject to the nonroad engine requirements of Parts 89
and 1039.
    The marine diesel engine program applies to all propulsion and
auxiliary engines with per cylinder displacement up to 30 liters.\124\
For purposes of these standards, these marine diesel engines are
categorized both by per cylinder displacement and by maximum engine
power.
---------------------------------------------------------------------------

    \124\ 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).
---------------------------------------------------------------------------

    According to our existing definitions, a marine engine is defined
as an engine that is installed or intended to be installed on a marine
vessel. Engines that are on a vessel but that are not ``installed'' are
generally considered to be land-based nonroad engines and are regulated
under 40 CFR part 89 or part 1039. Consistent with our current marine
diesel engine program, the standards adopted in this rule apply to
engines manufactured for sale in the United States or imported into the
United States beginning with the effective date of the standards. The
standards also apply to any engine installed for the first time in a
marine vessel after it has been used in another application subject to
different emission standards. In other words, an existing nonroad
diesel engine would become a new marine diesel engine, and subject to
the marine diesel engine standards, when it is marinized for use in a
marine application.
    Consistent with our current program, the marine engine standards we
are finalizing will not apply to marine diesel engines installed on
foreign vessels. While we received many comments requesting that we
extend the new standards to engines on foreign vessels operating in the
United States, we have determined that it is appropriate to postpone
this decision to our rulemaking for Category 3 marine diesel engines.
This will allow us to consider all engines on an ocean-going vessel as
a system; this may facilitate the application of advanced emission
control technologies because these engines often share a common fuel
and/or exhaust system. This approach is also consistent with the United
States Government's proposal to amend Annex VI of the International
Convention for the Prevention of Pollution from Ships (MARPOL)
currently under consideration at the International Maritime
Organization (IMO), which calls for significant emission reductions
from all engines on ocean-going vessels.\125\ EPA expects to finalize
new Category 3 engine emission standards in late 2009.\126\
---------------------------------------------------------------------------

    \125\ See ``Revision of the MARPOL Annex VI, the NOX
Technical Code and Related Guidelines; Development of Standards for
NOX, PM, and SOX,'' submitted by the United
States, BLG 11/15, Sub-Committee on Bulk Liquids and Gases, 11th
Session, Agenda Item 5, February 9, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0034. This document, along with the U.S. Statement concerning
the same, is also available on our Web site: www.epa.gov/otaq/
oceanvessels.com.
    \126\ See 72 FR 68518, December 5, 2007 for the new regulatory
deadline for the final rule for an additional tier of standards for
Category 3 rulemaking (final rule by December 17, 2009).
---------------------------------------------------------------------------

B. What Standards Are We Adopting?

(1) Locomotive Standards
(a) Line-Haul Locomotives
    We are setting new emission standards for newly-built and
remanufactured line-haul locomotives. Our standards for newly-built
line-haul locomotives will be implemented in two tiers: Tier 3, based
on engine design improvements, and Tier 4, based on the application of
the high-efficiency catalytic aftertreatment technologies now being
developed and introduced in the highway diesel sector. Our standards
for remanufactured line-haul locomotives apply to all Tier 0, 1, and 2
locomotives and are based on engine design improvements. Table III-1
summarizes the line-haul locomotive standards and implementation dates.
The feasibility of the new standards and the technologies involved are
discussed in detail in section III.C.

                                  Table III.--1 Line-Haul Locomotive Standards
                                                   [g/bhp-hr]
----------------------------------------------------------------------------------------------------------------
            Standards apply to                   Take effect in year            PM          NOX           HC
----------------------------------------------------------------------------------------------------------------
Remanufactured Tier 0 without separate      2008 as Available, 2010               0.22          8.0         1.00
 loop intake air cooling.                    Required.
Remanufactured Tier 0 with separate loop    2008 as Available, 2010               0.22          7.4         0.55
 intake air cooling.                         Required.
Remanufactured Tier 1.....................  2008 as Available, 2010               0.22          7.4         0.55
                                             Required.
Remanufactured Tier 2.....................  2008 as Available, 2013               0.10          5.5         0.30
                                             Required.
New Tier 3................................  2012.........................         0.10          5.5         0.30
New Tier 4................................  2015.........................         0.03          1.3         0.14
----------------------------------------------------------------------------------------------------------------

(i) Remanufactured Locomotives
    As proposed, we are setting new standards for the existing fleet of
Tier 0, Tier 1, and Tier 2 locomotives, to apply at the time of
remanufacture. These standards will also apply at the first
remanufacture of Tier 2 locomotives added to the fleet between now and
the start of Tier 3.
    Commenters have suggested that EPA adopt a naming convention for
the standards tiers to avoid confusion over whether, for example, the
terms ``Tier 0 standards'' and ``Tier 0 locomotives'' are referring to
the ``old'' Tier 0 standards adopted in 1998 or the ``new'' Tier 0
standards promulgated in this rule. A similar confusion may exist for
old and new Tier 1 and Tier 2 standards, including for marine engines.
The confusion is compounded by the fact that many of the locomotives
previously subject to the old Tier 0 standards will now be subject to
the new Tier 1 standards, and so a Tier 0 locomotive that is upgraded
to meet them could fairly be called a Tier 1 locomotive, and likewise
for Tier 2/Tier 3 standards.

    In response, we are adopting a simple approach whereby a Tier 0
locomotive remanufactured under the more stringent Tier 0 standards we
are adopting in this rule will be designated a Tier 0+ locomotive. A
Tier 0 locomotive originally manufactured with a separate loop intake
air cooling system that is remanufactured to the Tier 1+ standards will
be designated as a Tier 1+ locomotive. We are adopting the same
approach for Tier 1 and Tier 2 locomotives. That is, those
remanufactured under the new standards would be called Tier 1+ and Tier
2+ locomotives, respectively. We are also suggesting that in many
contexts, including a number of places in this final rule, there is
really no need to make distinctions of this sort, as no ambiguity
arises. In these contexts it would be perfectly acceptable to drop the
``+'' designation and simply refer to Tier 0, 1, and 2 locomotives and
standards.
    As described in section IV.B(3), the new Tier 0+, 1+, and 2+
standards (and corresponding switch-cycle standards) may apply when a
Tier 0, 1, or 2 locomotive is remanufactured anytime after this final
rule takes effect, if a certified remanufacture system is available.
However, this early certification is voluntary on the part of the
manufacturers, and so if no emissions control system is certified early
for a locomotive, these standards will instead apply beginning January
1, 2010 for Tier 0 and 1, and no later than January 1, 2013 for Tier 2.
We are also adopting the proposed reasonable cost provision, described
in section IV.B(3), to protect against the unlikely event that the only
certified systems made in the early program phase are exorbitantly
priced.
    Although under this approach, certification of new remanufacture
systems in the early phase of the program is voluntary, we believe that
developers will strive to certify systems to the new standards as early
as possible, even in 2008, to establish these products in the market,
especially for the locomotive models anticipated to have significant
numbers coming due for remanufacture in the next few years. This focus
on higher volume products also maximizes the potential for large
emission reductions very early in this program, greatly offsetting the
effect of slow turnover to new Tier 3 and Tier 4 locomotives inherent
in this sector.
    These remanufactured locomotive standards represent PM reductions
of about 50 percent for Tier 0 and Tier 1 locomotives, and
NOX reductions of about 20 percent for Tier 0+ locomotives
with separate loop aftercooling. Significantly, these reductions will
be substantial in the early years. This will be important to State
Implementation Plans (SIPs) being developed to achieve attainment with
the NAAQS, owing to the 2008 start date and relatively rapid
remanufacture schedule (roughly every 7 years, though it varies by
locomotive model and age).
    Some commenters argued for delaying the remanufactured locomotive
standards and some argued for accelerating them. However, little
technical justification was provided on either side and, after
reconsideration, we believe the proposed standards and dates are
appropriate. However, based on the comments, we have identified two
current Tier 0 locomotive models that are not likely to meet the new
standards under the full range of required test conditions, owing to
limitations in the original locomotive design. These are the General
Electric (GE) Dash-8 locomotives not equipped with separate loop
aftercooling, and the Electro-Motive Diesel (EMD) SD70MAC locomotives
that are equipped with separate loop aftercooling. As a result, we are
allowing an exception in ambient temperature and altitude conditions
under which these models, when remanufactured, must meet the new
standards, as detailed in the Part 1033 regulations. These exceptions
are limited to the extent that it is technically feasible to meet the
relevant standards under most in-use conditions.
(ii) Newly-Built Locomotives
    We are adopting the proposed Tier 3 and Tier 4 line-haul locomotive
standards but with an earlier start date for Tier 4 NOX,
along with an additional compliance flexibility option. We requested
comment in the NPRM on whether additional NOX emission
reductions would be feasible and appropriate for Tier 3 locomotives in
the 2012 timeframe, based on reoptimization of existing Tier 2
NOX control technologies, or the addition of new engine-
based technologies such as exhaust gas recirculation (EGR).
Manufacturers submitted detailed technical comments indicating that
achieving such reductions would result in a large fuel economy penalty,
a major engine redesign that would hamper Tier 4 technology
development, or both. Our own review of the technical options leads us
to the same conclusion and we are therefore finalizing the Tier 3
emissions standards as proposed.
    We proposed to allow manufacturers to defer meeting the Tier 4
NOX standard on newly-built locomotives until the 2017 model
year, in order to work through any implementation and technological
issues that might arise with advanced NOX control
technology. Even so, we expected that manufacturers would undertake a
single comprehensive redesign program for Tier 4, relying on the same
basic locomotive platform and overall emission control space
allocations for all Tier 4 product years. With this in mind, we
proposed that locomotives certified under Tier 4 in 2015 and 2016
without Tier 4 NOX control systems should have these systems
added when they undergo their first remanufacture and be subject to the
Tier 4 NOX standard thereafter.
    We received many comments from state and local air quality
agencies, and from environmental organizations, arguing that earlier
implementation of these advanced technologies is technologically
feasible and emphatically stating that they were needed to address the
nation's air quality problems. Further review of the test data
available for the proposed rule and of new test data available since
the proposal supports the argument for earlier implementation of Tier 4
NOX controls. This information is discussed in detail in
section III.C. Consequently, after considering this data and industry
comments regarding feasibility, we have concluded that the progress
made in the development of NOX aftertreatment technology has
been such that this proposed allowance to defer NOX control
is not consistent with our obligation under section 213(a)(3) of the
Clean Air Act to set standards that ``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.''
    We are therefore not adopting this allowance for deferred
NOX control in 2015-2016 Tier 4 locomotives, effectively
advancing the Tier 4 NOX standard for locomotives by two
years. Besides meeting our obligation under the Clean Air Act, this
change will simplify the certification and compliance program for all
stakeholders by providing a single step for Tier 4 implementation. It
will also provide substantial additional NOX reductions
during years that are important to some states for NAAQS attainment,
thus helping to address what was arguably the most critical comment we
received from state and local air agencies and environmental
organizations.
    We recognize that designing locomotives to meet the stringent Tier
4

standards in 2015 with the high levels of performance and reliability
demanded by the railroad industry will be challenging. As in other
recent EPA mobile source programs, we proposed and are finalizing
several compliance flexibility measures to aid the transition to these
very clean technologies. Specifically, we are adopting two distinct
compliance flexibility options for NOX that, while ensuring
the earliest possible introduction of advanced emission control, will
provide locomotive manufacturers some level of risk mitigation should
the technology solutions prove to be less robust than we project. The
first compliance flexibility is consistent with the flexibility program
described in our NPRM providing an in-use compliance margin for
NOX of 1.3 g/bhp-hr at full useful life (i.e., a 2.6 g/bhp-
hr emissions cap for in-use testing) for the first three Tier 4 model
years. See section IV.A(8) for details on this program.
    The second flexibility provision is an alternative NOX
compliance option that reduces the in-use NOX add-on to 0.6
g/bhp-hr (i.e., a 1.9 g/bhp-hr emissions cap for any in-use testing)
for model years 2015-2022. While significantly tightening the in-use
emissions cap, the provision provides manufacturers with significantly
more time to develop advanced NOX emission control systems
using real in-use experiences from the locomotive fleet. Complementing
this focus on improving technology through experience with the in-use
fleet, this provision also allows manufacturers to substitute
additional in-use tests on locomotives in lieu of the typical
production line testing requirements of our locomotive regulations.
This optional in-use testing would be in addition to the current in-use
testing requirements of our locomotive certification program. See
section IV.A(8) for details on this program.
    For reasons explained in the NPRM, Tier 4 line-haul locomotives
will not be required to meet standards on the switch cycle, but we are
requiring that newly-built Tier 3 locomotives and Tier 0 through Tier 2
locomotives remanufactured under this program be subject to switch
cycle standards, set at levels above the line-haul cycle standards.
Section III.B(1)(b) provides details.
(b) Switch Locomotives
    The NPRM discussed at some length the importance and challenges of
turning over today's large switch locomotive fleet to clean diesel. In
response, we proposed standards and other provisions aimed at
overcoming these challenges by encouraging the replacement of old high-
emitting units with newly-built or refurbished locomotives powered by
very clean engines developed for the nonroad equipment market.
    We are adopting the new standards for switch locomotives that we
proposed. As proposed, we are also continuing the existing Part 92
policy of requiring Tier 0 switch locomotives to only meet standards on
the switch cycle, while requiring Tier 1 and Tier 2 locomotives to meet
the applicable standards on both the line-haul and switch cycles. This
policy was adopted to ensure that manufacturers design emission
controls to function broadly over all notches. The switch cycle
standards shown in Table III-2 will require emission reductions
equivalent to those required by our new standards that apply over the
line-haul cycle. Note that these switch cycle standards also apply to
the Tier 3 and earlier line-haul locomotives that are subject to
compliance requirements on the switch cycle, as mentioned above and in
Section III.B(1)(b).
    We are also adopting the proposed Tier 3 and 4 emission standards
for newly-built switch locomotives, as shown in Table III-2. These
standards are slightly more stringent than the Tier 3 and Tier 4 line-
haul standards. Given these more stringent switch cycle standards, it
is not necessary to require to Tier 3 and 4 switchers to meet the line-
haul standards over the line-haul cycle.

                             Table III.--2 Emission Standards for Switch Locomotives
                                                   [g/bhp-hr]
----------------------------------------------------------------------------------------------------------------
   Switch locomotive standards apply to          Take effect in year            PM          NOX           HC
----------------------------------------------------------------------------------------------------------------
Remanufactured Tier 0.....................  2008 as available, 2010               0.26         11.8         2.10
                                             required.
Remanufactured Tier 1.....................  2008 as available, 2010               0.26         11.0         1.20
                                             required.
Remanufactured Tier 2.....................  2008 as available, 2013               0.13          8.1         0.60
                                             required.
Tier 3....................................  2011.........................         0.10          5.0         0.60
Tier 4....................................  2015.........................         0.03          1.3         0.14
----------------------------------------------------------------------------------------------------------------

    We are also finalizing the proposed streamlined certification
option to help in the early implementation of the switch locomotive
program. As described in section IV.B(9), during a 10-year program
start-up period aimed at encouraging the turnover of the existing
switcher fleet to the new cleaner engines, switch locomotives may use
nonroad-certified engines (Table III-3) without need for an additional
certification under the locomotive program. In the years before the
nonroad Tier 4 start dates, we are making this provision available
using pre-Tier 4 nonroad engines meeting today's standards of 0.15 g/
bhp-hr PM and 3.0/4.8 g/bhp-hr NOX+NMHC (below/above 750
hp), because switchers built with these nonroad engines will still be
much cleaner than those meeting the current switch locomotive Tier 2
standards of 0.24 and 8.1 g/bhp-hr PM and NOX, respectively.
    Commenters suggested that we allow the use of even earlier-tier
nonroad engines under this option, as these would still be
substantially cleaner than the engines being replaced. However, we feel
this would defeat the purpose of the program, and would not be
justifiable on a feasibility basis, as current-tier nonroad engines
will be available for incorporation into new switchers in any year of
the program. We are adopting other compliance and ABT provisions
relevant to switch locomotives as discussed in section IV.B(1), (2),
(3), and (9).

                          Table III.--3 Relevant Large Nonroad Engine Tier 4 Standards
                                                   [g/bhp-hr]
----------------------------------------------------------------------------------------------------------------
             Engine power                Model year       PM                            NOX
----------------------------------------------------------------------------------------------------------------
At or Below 750 hp....................         2011         0.01  3.0 (NOX+NMHC) \a\
                                               2014         0.01  0.30
750-1200 hp...........................         2011        0.075  2.6
                                               2015         0.02  0.50
Over 1200 hp..........................         2011        0.075  0.50 genset; 2.6 non-genset 0.50
                                               2015         0.02
----------------------------------------------------------------------------------------------------------------
Note: (a) 0.30 NOX for 50% of sales in 2011-2013, or alternatively 1.5 g NOX for 100% of sales.

    Finally, we are revising the definition of a switch locomotive to
make clear that it is the total switch locomotive power rating
(including power from any auxiliary engines that can operate when a
main engine is operating), and not the individual engine power rating,
that must be below 2300 hp to qualify, and to drop the unnecessary
requirement that it be designed or used primarily for short distance
operation. This clears up the ambiguity in the Part 92 definition over
multi-engine switchers.
(c) Reduction of Locomotive Idling Emissions
    We are adopting the proposed requirement that an Automatic Engine
Stop/Start System (AESS) be used on all new Tier 3 and Tier 4
locomotives and installed on all existing locomotives that are subject
to the new remanufactured engine standards, at the point of first
remanufacture under the new standards. Locomotives equipped with an
AESS device under this program must shut down the locomotive engine
after no more than 30 continuous minutes of idling, and be able to stop
and start the engine at least six times per day without causing engine
damage or other serious problems. Continued idling is allowed under the
following conditions: to prevent engine damage such as damage caused by
coolant freezing, to maintain air pressure for brakes or starter
systems, to recharge the locomotive battery, to perform necessary
maintenance, or to otherwise comply with applicable government
regulations.
    Commenters also pointed out that it can sometimes be appropriate to
allow a locomotive to idle to heat or cool the cab, and we are adopting
regulations to allow it where necessary. Our implementation of this
provision will rely on the strong incentive railroads have to limit
idling to realize fuel cost savings after they have invested capital by
installing an AESS system on a locomotive. We expect the railroads to
appropriately develop policies instructing operators when it is
acceptable to idle the locomotive to provide heating or cooling to the
locomotive cab. We do not believe that those individuals responsible
for developing railroad policies have any incentive to encourage or
allow unnecessary idling. It is our intention to stay abreast of how
well this combination of idle control systems and railroad policies
does in fact accomplish the intended goal of reducing unnecessary
idling. In general, we may consider it to be circumvention of this
provision for an individual operator to use the AESS system in a manner
other than that for which the system was designed and implemented per a
railroad's policy directive.
    A further reduction in idling emissions can be achieved through the
use of onboard auxiliary power units (APUs), either as standalone
systems or in conjunction with an AESS. In contrast to AESS, which
works to reduce unnecessary idling, the APU goes further by also
reducing the amount of time when locomotive engine idling is necessary,
especially in cold weather climates. APUs are small (less than 50 hp)
diesel engines that stop and start themselves as needed to provide:
heat to both the engine coolant and engine oil, power to charge the
batteries, and power to run accessories such as those required for cab
comfort. This allows the much larger locomotive engine to be shut down
while the locomotive remains in a state of readiness, thereby reducing
fuel consumption without the risk of the engine being damaged in cold
weather. APUs are powered by nonroad engines compliant with EPA or
State of California nonroad engine standards, and emit at much lower
levels than an idling locomotive under current standards.
    Some commenters suggested we require both an AESS and an APU.
However, the amount of idle reduction an APU can provide is dependent
on a number of variables, such as the function of the locomotive (e.g.,
a switcher or a line-haul), where it operates (i.e., geographical
area), and its operating characteristics (e.g., number of hours per day
that it operates). As we stated in the NPRM, at this time we are not
requiring that APUs be installed on every locomotive because it is not
clear how much additional benefit they would provide outside of regions
and times of the year where low temperatures or other factors that
warrant the use of an APU exist and because they do involve some
inherent design and operational complexities that could not be
justified without such commensurate benefits. We are, however, adopting
the proposed provision to encourage the additional use of APUs by
providing in our test regulations, a process by which the manufacturer
can appropriately account for the proven emission benefits of a more
comprehensive idle reduction system.
    In response to comment, we are adopting a more flexible approach
that will allow the idle reduction requirement for remanufactured Tier
0+, 1+, and 2+ locomotives to be addressed in a separate certification
apart from the certification of the full remanufacture system. Under
this approach, remanufacturers will be allowed to obtain a certificate
for a system that meets all of the requirements of part 1033 except for
those of Sec.  1033.115(g). However, since the idle controls would
still need to be installed in a certified configuration before the
remanufactured locomotive is returned to service, some other entity
would need to obtain a certificate to cover the requirements of Sec.
1033.115(g). (This separate certification approach is somewhat
analogous to allowing a motor vehicle engine manufacturer to hold the
certificate for exhaust emission standards and a motor vehicle
manufacturer to hold the certificate for evaporative emission standards
for a single motor vehicle.) Note that manufacturers of freshly
manufactured locomotives and their customers will also have the choice
as to whether the AESS is installed as part of the certified engine
configuration at the factory or by an aftermarket company pursuant to a
separate certification before the freshly manufactured locomotive is
put into

service. These provisions will allow more companies to remain in the
AESS manufacturing market and thus provide more choices to the
railroads.
    As described in Chapter 5 of the RIA, manufacturers of AESS, and
demonstrations done in partnership between government and industry have
shown that for most locomotives the fuel savings that result in the
first few years after installation of an AESS system will offset the
cost of adding the system to the locomotive. Given these short payback
times for adding idle reduction technologies to a typical locomotive,
normal market forces have led many railroads to retrofit a number of
their locomotives with such controls. However, as is common with
pollution, market prices generally do not account for the external
social costs of the idling emissions, leading to an underinvestment in
idling reduction systems. This rulemaking addresses those locomotives
for which the railroads judge the fuel savings insufficient to justify
the cost of the retrofit. We believe that applying AESS to these
locomotives is appropriate when one also considers the significant
emissions reductions that will result.
(2) Marine Diesel Engine Standards
(a) Newly-Built Marine Engines
    We are adopting Tier 3 and Tier 4 emission standards for newly-
built marine diesel engines with displacements under 30 liters per
cylinder. Our analysis of the feasibility of these standards is
summarized in section III.C and detailed in the RIA.
    We are retaining our existing per-cylinder displacement approach to
establishing cutpoints for standards, but are revising and refining it
in several places to ensure that the appropriate standards apply to
every group of engines in this very diverse sector and to provide for
an orderly phase-in of the program to spread out the redesign workload
burden:
    We are moving the C1/C2 cutpoint from 5 liters/cylinder to 7
liters/cylinder, because the latter is a more accurate cutpoint between
today's high- and medium-speed diesels.
    We are revising the per-cylinder displacement cutpoints within
Category 1 to better define the application of standards.
    An additional differentiation is made between high power density
engines typically used in planing vessels and standard power density
engines, with a cutpoint between them set at 35 kW/liter (47 hp/liter).
    We are removing the distinction for marine diesels under 37 kW (50
hp) in Category 1, originally made because these were regulated under
our nonroad engine program.
    Finally, we will further group engines by maximum engine power,
especially in regards to setting appropriate long-term aftertreatment-
based standards.
    Note that we are retaining the differentiation between recreational
and non-recreational marine engines within Category 1 because there are
differences in their certification programs. Also, as discussed below,
we are not finalizing Tier 4 standards for recreational marine engines
at this time. Section IV.C(10) clarifies the definition of recreational
marine diesel engine.
    The new standards and implementation schedules are shown on Tables
III-4 through 7. Briefly summarized, the marine diesel standards
include stringent engine-based Tier 3 standards, phasing in over 2009-
2014. They also include aftertreatment-based Tier 4 standards for
commercial marine engines at or above 600 kW (800 hp), phasing in over
2014-2017. For engines of power levels not included in the Tier 3 and
Tier 4 tables, the previous tier of standards (Tier 2 or Tier 3,
respectively) continues to apply. These standards and implementation
dates are the same as those proposed except: (1) Recreational marine
engines are not subject to Tier 4 standards; (2) The Tier 4
NOX standard for 2000-3700 kW engines has been pulled
forward by two years; (3) The proposed optional Tier 4 approach
coordinated with locomotive Tier 4 has been modified; and (4) based on
comments we received, the Tier 3 standards for high power density
engines in the 3.5 to 7 liter/cylinder category (Table III-5) have been
adjusted slightly to better align them with standards in other
categories. The first three of these changes are discussed in more
detail below. See section <IP_ADDRESS> of the Summary and Analysis of
Comments document for discussion of the fourth.

                                  Table III-4.--Tier 3 Standards for Marine Diesel C1 Commercial Standard Power Density
--------------------------------------------------------------------------------------------------------------------------------------------------------
         Maximum engine power                     L/cylinder                PM  g/bhp-hr (g/kW-hr)       NOX+HC \d\ g/bhp-hr  (g/kW-hr)     Model year
--------------------------------------------------------------------------------------------------------------------------------------------------------
<19 kW................................  <0.9                            0.30 (0.40)                    5.6 (7.5)                                    2009
--------------------------------------------------------------------------------------------------------------------------------------------------------
19 to <75 kW..........................  <0.9 \a\                        0.22 (0.30)                    5.6 (7.5)                                    2009
                                                                        0.22 (0.30) \b\                3.5 (4.7) \b\                                2014
--------------------------------------------------------------------------------------------------------------------------------------------------------
75 to <3700 kW........................  <0.9                            0.10 (0.14)                    4.0 (5.4)                                    2012
                                        0.9-<1.2                        0.09 (0.12)                    4.0 (5.4)                                    2013
                                        1.2-<2.5                        0.08 (0.11) \c\                4.2 (5.6)                                    2014
                                        2.5-<3.5                        0.08 (0.11) \c\                4.2 (5.6)                                    2013
                                        3.5-<7.0                        0.08 (0.11) \c\                4.3 (5.8)                                   2012
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
(a) <75 kW engines at or above 0.9 L/cylinder are subject to the corresponding 75-3700 kW standards.
(b) Option: 0.15 g/bhp-hr (0.20 g/kW-hr) PM/4.3 g/bhp-hr (5.8 g/kW-hr) NOX+HC in 2014.
(c) This standard level drops to 0.07 g/bhp-hr (0.10 g/kW-hr) in 2018 for <600 kW engines.
(d) Tier 3 NOX+HC standards do not apply to 2000-3700 kW engines.

                           Table III-5.--Tier 3 Standards for Marine Diesel C1 Recreational and Commercial High Power Density
--------------------------------------------------------------------------------------------------------------------------------------------------------
         Maximum engine power                     L/cylinder                PM g/bhp-hr  (g/kW-hr)         NOX+HC g/bhp-hr  (g/kW-hr)       Model year
--------------------------------------------------------------------------------------------------------------------------------------------------------
<19 kW................................  <0.9                            0.30 (0.40)                    5.6 (7.5)                                    2009
--------------------------------------------------------------------------------------------------------------------------------------------------------
19 to <75 kW..........................  <0.9 \a\                        0.22 (0.30)                    5.6 (7.5)                                    2009

                                        ..............................  0.22 (0.30) \b\                3.5 (4.7) \b\                                2014
--------------------------------------------------------------------------------------------------------------------------------------------------------
75 to <3700 kW........................  <0.9                            0.11 (0.15)                    4.3 (5.8)                                    2012
                                        0.9-<1.2                        0.10 (0.14)                    4.3 (5.8)                                    2013
                                        1.2-<2.5                        0.09 (0.12)                    4.3 (5.8)                                    2014
                                        2.5-<3.5                        0.09 (0.12)                    4.3 (5.8)                                    2013
                                        3.5-<7.0                        0.08 (0.11)                    4.3 (5.8)                                   2012
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
(a) <75 kW engines at or above 0.9 L/cylinder are subject to the corresponding 75-3700 kW standards.
(b) Option: 0.15 g/bhp-hr (0.20 g/kW-hr) PM/4.3 g/bhp-hr (5.8 g/kW-hr) NOX+HC in 2014.

                             Table III-6.--Tier 3 Standards for Marine Diesel C2 \a\
----------------------------------------------------------------------------------------------------------------
                                                       PM g/bhp-hr  (g/kW-   NOX+HC \b\ g/bhp-hr
     Maximum engine power            L/cylinder                hr)                (g/kW-hr)         Model year
----------------------------------------------------------------------------------------------------------------
<3700 kW.....................  7-<15                  0.10 (0.14)           4.6 (6.2)                       2013
                               15-<20                 0.20 (0.27) \c\       5.2 (7.0)                       2014
                               20-<25                 0.20 (0.27)           7.3 (9.8)                       2014
                               25-<30                 0.20 (0.27)           8.2 (11.0)                     2014
----------------------------------------------------------------------------------------------------------------
Notes:
(a) See note (c) of Table III-7 for optional Tier 3/Tier 4 standards.
(b) Tier 3 NOX+HC standards do not apply to 2000-3700 kW engines.
(c) For engines below 3300 kW in this group, the PM Tier 3 standard is 0.25g/bhp-hr (0.34 g/kW-hr).

                           Table III-7.--Tier 4 Standards for Marine Diesel C1 and C2
----------------------------------------------------------------------------------------------------------------
                                PM g/bhp-hr  (g/kW-   NOX g/bhp-hr  (g/kW-   HC g/bhp-hr  (g/kW-
     Maximum engine power               hr)                    hr)                   hr)            Model year
----------------------------------------------------------------------------------------------------------------
At or above 3700 kW..........  0.09 (0.12) \a\        1.3 (1.8)             0.14 (0.19)                 \c\ 2014
                               0.04 (0.06)            1.3 (1.8)             0.14 (0.19)                 b c 2016
----------------------------------------------------------------------------------------------------------------
2000 to <3700 kW.............  0.03 (0.04)            1.3 (1.8)             0.14 (0.19)                 c d 2014
1400 to <2000 kW.............  0.03 (0.04)            1.3 (1.8)             0.14 (0.19)                   c 2016
600 to <1400 kW..............  0.03 (0.04)            1.3 (1.8)             0.14 (0.19)                  b 2017
----------------------------------------------------------------------------------------------------------------
Notes:
(a) This standard is 0.19 g/bhp-hr (0.25 g/kW-hr) for engines with 15-30 liter/cylinder displacement.
(b) Optional compliance start dates can be used within these model years; see discussion below.
(c) Option for C2: Tier 3 PM/NOX+HC at 0.10 / 5.8 g/bhp-hr (0.14/7.8 g/kW-hr) in 2012, and Tier 4 in 2015.
(d) The Tier 3 PM standards continue to apply for these engines in model years 2014 and 2015 only.

    Engine manufacturers argued that modifying standard power density
engines between 2000 and 3700 kW for Tier 3 NOX, and again
for Tier 4 NOX shortly after would be too difficult. They
argued that these engines could meet Tier 4 NOX in 2014, two
years earlier, if the Tier 3 NOX+HC standard, proposed to
apply in 2012, 2013, or 2014, depending on displacement, did not have
to be met. We have analyzed this group of engines and agree that the
suggested approach would be feasible and would have very little
detrimental effect on NOX reductions in 2012-2013, while
providing significant additional NOX reductions thereafter.
We are therefore leaving the Tier 3/Tier 4 PM standards as proposed but
revising the NOX implementation schedule as suggested by the
industry.
    The Tier 3 standards for engines with maximum engine power less
than 75 kW (100 hp) are based on the nonroad diesel Tier 2 and Tier 3
standards, because these smaller marine engines are largely derived
from (and often nearly identical to) the nonroad engine designs. The
relatively straightforward carry-over nature of this approach also
allows for an early implementation schedule, in model year 2009,
providing substantial early benefits to the program. However, some of
the nonroad engines less than 75 kW are also subject to aftertreatment-
based Tier 4 nonroad standards, and our new program does not carry
these over into the marine sector, due to vessel design and operational
constraints discussed in section III.C. Because of the widespread use
of both direct- and indirect-injection diesel engines in the 19 to 75
kW (25-100 hp) engine market today, we are making two options available
to manufacturers for meeting Tier 3 standards on any engine in this
range, as indicated in Table III-4. One option focuses on lower PM and
the other on lower NOX, though both require substantial
reductions in both PM and NOX and will take effect in 2014.
    With important exceptions, we are subjecting marine diesel engines
at or above 75 kW (100 hp) to new emissions standards in two steps,
Tier 3 and Tier 4. The Tier 3 standards are based on the engine-out
emission reduction potential (apart from the addition of exhaust
aftertreatment) of the nonroad Tier 4 diesel engines that will be
introduced beginning in 2011. The Tier 3 standards for C1 engines will
phase in over 2012-2014. We believe it is appropriate to coordinate the
marine Tier 3 standards

with the nonroad Tier 4 (rather than Tier 3) engine developments in
this way because marine diesel engines are largely derived from land-
based nonroad counterparts, and because the advanced fuel and
combustion systems that we expect the Tier 4 nonroad engines to employ
will allow approximately a 50 percent reduction in PM when compared to
the reduction potential of the nonroad Tier 3 engines. Inserting an
additional marine engine tier based on nonroad Tier 3 engines would
result in overly short lead time and stability periods and/or a delay
in stringent standards.
    We are applying high-efficiency aftertreatment-based Tier 4
standards to all commercial and auxiliary C1 and C2 engines over 600 kW
(800 hp). These standards will phase in over 2014-2017. Marine diesels
over 600 kW, though fewer in number, are the workhorses of the inland
waterway and intercoastal marine industry, running at high load
factors, for many hours a day, over decades of heavy use. As a result
they also account for the bulk of marine diesel engine emissions.
    After considering the substantial number of comments received on
the feasibility of extending Tier 4 standards to engines below 600 kW,
we are not at this time setting Tier 4 standards for these engines. We
may do so at some point in the future if further technology
developments show a path to address the issues we identify in RIA
chapter 4 with the application of aftertreatment technologies to
smaller vessels.
    We are also not extending the Tier 4 program to recreational marine
diesel engines. In our proposal we indicated that at least some
recreational vessels, those with engines above 2000 kW (2760 hp), have
the space and design layout conducive to aftertreatment-based controls
and professional crews who oversee engine operation and maintenance.
This suggested that aftertreatment-based standards would be feasible
for these larger recreational engines. While commenters on the proposal
did not disagree with these views, they pointed out these very large
recreational vessels often travel outside the United States, and, for
tax reasons, flag outside the U.S. as well. Commenters argued that
applying Tier 4 standards to large recreational marine diesel engines
would further discourage U.S.-flagging because vessels with those
engines would be limited to using only those foreign ports that make
ULSD and reductant for NOX aftertreatment available at
recreational docking facilities, limiting their use and hurting the
vessel's resale value. The aftertreatment devices used to meet Tier 4
are expected to be sensitive to sulfur in the exhaust and so ULSD must
be used in these engines.
    In general, we expect ULSD to become widely available worldwide,
which would help reduce these concerns. However, there are areas such
as Latin America and parts of the Caribbean that currently do not plan
to require use of this fuel. Even in countries where ULSD is available
for highway vehicles but not mandated for other mobile sources,
recreational marinas may choose to not make ULSD and reductant
available if demand is limited to a small number of vessels, especially
if the storage and dispensing costs are high. To the extent the fuel
requirements for Tier 4 engines encourage vessel owners to flag outside
the United States, the results would be increased emissions since the
international standards for these engines are equivalent to EPA's Tier
1 standards.
    After considering the above, we conclude that it is preferable at
this time to hold recreational engines marine diesel engines to the
Tier 3 standards. We plan to revisit this decision when we consider the
broader questions of the application of our national marine diesel
engine standards to engines on foreign vessels that enter U.S. ports in
the context of our Category 3 marine diesel engine rulemaking.
    There is a group of commercial vessels that share some of the
characteristics of recreational vessels in that they also operate
outside the United States. However, the concerns that lead us to
exclude recreational vessels from the Tier 4 standards (flagging or
registering in a foreign country and thus avoiding all U.S. emission
standards; resale value) do not generally apply to commercial vessels.
Unlike recreational vessels, the majority of commercial vessels with C1
or C2 main propulsion engines that operate in the United States do not
have the option of flagging offshore. This is because they are engaged
full-time in harbor activities in U.S. ports or in transporting freight
or otherwise operating only between two U.S. ports, and cabotage laws
require such vessels be flagged in the United States. In addition, most
of these vessels operate at or between U.S. ports, so ULSD availability
is not expected to be a problem. Finally, the resale of U.S. commercial
vessels on the world market is already affected by other U.S.-specific
vessel design and operation requirements, and these standards are not
expected to affect that situation.
    Nevertheless, some commercial vessels are used in ways that could
make the use of ULSD and even urea an intractable problem. These are
commercial vessels that are routinely operated outside of the United
States for extended periods of time, including tug/barge cargo vessels
operated on circle routes between the United States and Latin America
that routinely refuel in places where ULSD is not available, and lift
boats, utility boats, supply boats and crewboats that are used in the
offshore drilling industry and are contracted to work in waters off
Latin America or Western Africa for up to several years at a time
without returning to the United States. Owners of these vessels
informed us that requiring them to use Tier 4 engines will adversely
impact their business in significant ways since they would have to
arrange for ULSD and urea outside the United States, potentially at
great additional cost, and that this is turn would affect their ability
to compete with foreign transportation providers who do not face the
same costs. These owners flag their vessels in the U.S. to maximize the
flexibility of their business operations, but they informed us that
they would consider segregating their fleets and flagging some
elsewhere if they are required to use Tier 4 engines. Similar to the
recreational marine case, the engines on reflagged vessels would not be
subject to any U.S. emission controls or compliance requirements. In
addition, there could be adverse impacts on associated industries that
use these services, if there are fewer vessels available for use in the
Untied States. For all of these reasons, these vessel owner/operators
encouraged EPA to consider a provision that would not require these
vessels to use Tier 4 engines.
    We do not expect ULSD availability at foreign commercial ports to
be a widespread problem. Many industrial nations already have or are
expected to shift to ULSD in the near future, including Japan (by
2008), Singapore (in 2007), Mexico (in 2007 for ``Northern border
areas''), the EU member states (by 2009), and Australia (by 2009).
Other countries may also make ULSD available by 2016, as refineries in
other countries modify their production to supply ULSD to the U.S.
markets even if they do not require it domestically. However, ULSD may
be difficult to obtain in some areas of the world, notably Latin
America and Africa. Therefore, it is reasonable to include a limited
compliance exemption from the Tier 4 standards for the narrow set of
vessels that are described above.
    Because the decision of whether a Tier 4 engine is required must be
made at the design phase of a vessel, and not after it goes into
service, it is preferable to define such an exemption based on vessel
design characteristics instead of

the owner's intentions for how the vessel may ultimately be used. After
consulting with industry representatives, we concluded that the most
obvious design feature that indicates the vessel is intended for
extensive international use is compliance with international safety
standards. We have concluded that the costs of obtaining and
maintaining certification for the International Convention for the
Safety of Life at Sea (SOLAS) are high enough to discourage owners of
vessels that will not be used outside the United States to obtain
certification to evade the Tier 4 standards. These costs can range from
about $250,000 to $1 million in capital costs and from about $50,000 to
$100,000 in annual operating costs. The Port State Information Exchange
database maintained by the U.S. Coast Guard indicates that about 30
percent of offshore supply vessels built annually are SOLAS certified
and that 3 percent or fewer passenger vessels and tugs built annually
are SOLAS certified (based on new vessel construction, 1995-2006).\127\
Therefore, to be eligible for the exemption, the owner will be required
to obtain and maintain relevant international safety certification
pursuant to the requirements of the United States Coast Guard and SOLAS
for the vessel on which an exempted engine is installed.
---------------------------------------------------------------------------

    \127\ Memorandum to Docket EPA-HQ-OAR-2003-0190, Marine
Vessels--SOLAS Certification, from Jean MarieRevelt, dated January
11, 2007.
---------------------------------------------------------------------------

    Vessel owners will be required to petition EPA for an exemption for
a particular vessel in order for an engine manufacturer to sell them an
exempted engine; granting of the exemption will not be automatic. In
evaluating a request for a Tier 4 exemption, we will consider the
owner's projections of how and where the vessel will be used and the
availability of ULSD in those areas, as well as the mix of SOLAS and
non-SOLAS vessels in the owner's current fleet and the extent to which
those vessels are being or have been operated outside the United
States. In general, it is our expectation that fleets should first use
existing pre-Tier 4 vessels for operations where ULSD may not be
available. Therefore, we would not expect to grant an exemption for a
vessel that will be part of a fleet that does not already have a
significant percentage of Tier 4 vessels, since a fleet with a smaller
percentage of Tier 4 vessels would likely have more pre-Tier 4 vessels
that could be employed in the overseas application instead. For
example, if 30 percent of an owner's current fleet has SOLAS
certification, we would expect that up to 70 percent of the vessels in
that fleet could be Tier 4 compliant without changes in the operation
of the fleet. We may also ask the petitioner to demonstrate that other
vessels in the petitioner's fleet remain in service outside the United
States and have not been placed into service domestically. EPA does not
expect to approve applications for the Tier 4 exemption described in
this paragraph prior to 2021; we expect that the existing fleet of Tier
3 vessels can be used for overseas operations during that time. If an
owner petitions EPA for an exemption prior to that year, we may request
additional information on the owner's expected operation plans for that
vessel and a more complete explanation as to why another vessel in the
existing fleet could not be redirected to the offshore application with
the Tier 4 vessel under construction taking that vessel's place.
Finally, a failure to maintain SOLAS certification for the vessel on
which an exempted engine is installed would result in a finding of
noncompliance and the owner would be liable for applicable fines and
other penalties.
    To address the situation in which an owner of a vessel with Tier 4
engines wants to use that vessel in a country that does not have ULSD
available, we are also including a provision that will allow the owner
to petition EPA to temporarily remove or disable the Tier 4 controls on
vessels that are operated solely outside the United States for a given
period of time. The petitioner will need to specify where the vessel
will operate, how long the vessel will operate there, and why the owner
will be unable to provide ULSD for the vessel. The petitioner will also
be required to describe what actions will be taken to disable or
disconnect the Tier 4 controls. Permission to disable or remove the
Tier 4 controls will be allowed only for the period specified by the
owner and agreed to by EPA; however, the owner may re-petition EPA at
the end of that period for an extension. As part of the approval of
such a petition, the petitioner will be required to agree to re-install
or reconnect the Tier 4 emission control devices prior to re-entry into
the United States, whether this occurs only at the end of the specified
period or earlier.
    These provisions for migratory vessels are intended to facilitate
the use of vessels certified to the U.S. federal marine diesel emission
standards while they are operated for extended periods in areas that
may not have ULSD available. It should be noted that vessels that
receive either limited exemptions or that petition EPA to remove or
disable Tier 4 controls will still be subject to the MARPOL emission
limits when they are operated outside the United States. We may review
these migratory vessel provisions in the context of our upcoming
Category 3 marine diesel engine rulemaking. We may also revisit this
program in the future if the number of exemption requests appears to be
unreasonably high or if we find that significant numbers of vessels
that have obtained exemptions from Tier 4 are, in fact, in use
domestically.
    Note that the implementation schedule in the above marine standards
tables is expressed in terms of model years, consistent with past
practice and the format of our regulations. However, in two cases we
believe it is appropriate to provide a manufacturer the option to delay
compliance somewhat, as long as the standards are implemented within
the indicated model year. Specifically, we are allowing a manufacturer
to delay Tier 4 compliance within the 2017 model year for 600-1000 kW
(800-1300 hp) engines by up to 9 months (but no later than October 1,
2017) and, for Tier 4 PM, within the 2016 model year for engines at or
above 3700 kW (4900 hp) by up to 12 months (but no later than December
31, 2016). We consider this option to delay implementation appropriate
in order to give some flexibility in spreading the implementation
workload and ensure a smooth transition to the long-term Tier 4
program.
    The Tier 4 standards for locomotives and for C2 diesel marine
engines of comparable size are at the same numerical levels but differ
somewhat in implementation schedule: Locomotive Tier 4 standards start
in 2015, while diesel marine Tier 4 standards start in 2016 for engines
in the 1400-2000 kW (1900-2700 hp) range, and in 2014 for engines over
2000 kW (with final PM standards starting in 2016 for these engines).
We consider these locomotive and marine diesel Tier 4 implementation
schedules to be close enough to warrant our adopting a marine engine
option based on the Tier 4 locomotive schedule, aimed at facilitating
continuance of today's frequent practice of developing a common engine
platform for both markets. Commenters on the proposal supported this
marine engine option, but expressed concerns about competitiveness
issues and argued that we should remove the proposed restriction to
engines of 7-15 liter/cylinder displacement and under 3700 kW maximum
engine power.
    We are adopting this locomotive-based marine engine option, but
with

some changes from the proposed approach to address potential
competitiveness issues, as well as our own concern that this option be
used only for the intended purpose of avoiding unnecessary dual design
efforts. First, we are retaining some limits on its scope, specifically
to engines above both a 7 liters per cylinder limit (Category 2 in the
marine sector) and a 1400 kW (1900 hp) maximum engine power. Second, if
the option is used, its standards must be met for all of a
manufacturer's marine engines at or above 1400 kW (1900 hp) in the same
displacement category (that is, 7-15, 15-20, 20-25, or 25-30 liters per
cylinder) in all of the model years 2012 through 2016. This will help
ensure the option is not gamed by artificially subdividing engine
platforms. Because the switch locomotive program we are establishing
already includes a similar streamlined option allowing the use of land-
based nonroad engines, we are not extending this option to switchers.
    We are adopting another provision to help ensure that this
locomotive-based marine engine option is environmentally beneficial and
is not used to gain a competitive advantage. We are requiring that
marine engines under this option meet Tier 3 standards in 2012, the
year Tier 3 starts for locomotives, with standards numerically
corresponding to locomotive Tier 3 standards levels: 0.14 g/kW-hr (0.10
g/bhp-hr) PM and 7.8 g/kW-hr NOX+HC (5.8 g/bhp-hr: that is,
5.5 + 0.30 g/bhp-hr combined NOX and HC). Otherwise a
manufacturer could take advantage of the later-starting marine Tier 3
schedule to generate credits or allow increased emissions from these
engines until 2015 when the option requires Tier 4 compliance. This
approach also deals fairly with the problem identified in the proposal
regarding redesigning locomotive-based engine platforms to meet the
numerically lower marine Tier 3 NOX level.
    Finally, we considered but are not adopting a provision that would
set a total vessel power limit for the Tier 4 standards. The comments
we received on this issue lead us to conclude that multiple-engine
configurations are used in vessel designs for specific purposes and are
not likely to be employed to evade the Tier 4 standards. We may
consider this type of restriction in a future action, however, if
multiple-engine vessels are built in applications that have typically
used a different number of engines in the past.
(b) Remanufactured Marine Engines
    In addition to the standards for newly-built engines, we are
adopting for the first time emission standards for marine diesel
engines on existing vessels. Many of these existing engines will remain
in the fleet for 40 years or more, making them what would otherwise be
a substantial source of air pollution. The marine remanufacture program
will provide early PM reductions by reducing emissions from this legacy
fleet sooner than would be the case from the retirement of old vessels
in favor of new vessels with cleaner engines. Additional early
NOX reductions are expected to be achieved from the use of
locomotive remanufacture systems recertified under this program for
Category 2 engines.
    The program we are finalizing is modified from what we described in
the NPRM. In the NPRM we described a two-part program that would have
applied to all commercial marine diesel engines above 600 kW when they
are remanufactured. In the first part, which we considered beginning as
early as 2008, vessel owners/operators and engine rebuilders who
remanufacture engines would be required to use a certified
remanufacture system when an engine is remanufactured (defined as
replacement of all cylinder liners, either in one event or over a five-
year period) if such a certified system is available. In the second
part, which we considered beginning in 2013, a marine diesel engine
identified by EPA as a high-sales volume engine model would have been
required to meet specified emission requirements when it is
remanufactured. Specifically, the remanufacturers or owners of such
engines would have been required to use systems certified to meet the
standard; if no certified system is available, they would have needed
to either retrofit the engines with emission reduction technology that
demonstrates at least a 25 percent reduction or replace the engines
with new ones. For engines not identified as high-sales volume engines,
Part 1 would have continued to apply.
    Several commenters requested that EPA not finalize this program at
this time but instead consider it in a separate rulemaking. They noted
that this would allow additional time to consider the program and its
requirements. Postponing the program, however, would also result in the
loss of important emission reductions early in the program. Delay is
also not necessary because the program we are adopting consists only of
the first part of the program described in our proposal, requiring the
owner of a marine diesel engine to use a certified marine remanufacture
system when the engine is remanufactured if such a system is available.
We are not adopting a requirement for the mandatory availability of
remanufacture systems. (Under the option discussed in the proposal, in
certain circumstances, if a remanufacture system was not made available
the owner would have been required to retrofit an emission control
technology, repower the vessel (replace its engines) or scrap the
vessel.)
    The marine remanufacture program we are adopting applies to all
commercial marine diesel engines with maximum engine power greater than
600 kW and manufactured in 1973 or later, through Tier 2. The beginning
date of 1973 is based on our existing locomotive program; many of the
techniques used to achieve those standards are expected to be
applicable to marine diesel engines over 600 kW.
    As described in more detail below, the program draws on aspects of
our locomotive remanufacture and diesel retrofit programs with regard
to the basic requirements that apply and how remanufacture systems are
certified. The remainder of this section describes the main features of
the program. The technological feasibility of this program is described
in section III.C, and the certification requirements are set out in
section IV. Small manufacturer, engine dresser, vessel builder, and
operator flexibilities are set out in section IV.A(13)(b).
    Similar to the locomotive program, the marine program we are
finalizing applies when a marine diesel engine is remanufactured.
Covered engines are those that are remanufactured to as-new condition.
Based on discussions with engine manufacturers, we have determined that
replacing all cylinder liners is a simple and clear indicator that the
servicing being done is extensive enough for the engine to be
considered functionally equivalent to a freshly manufactured engine,
both mechanically and in terms of how it is used. Therefore, we are
defining remanufacture as the removal and replacement of all cylinder
liners, either during a single maintenance event or over a five-year
period. It should be noted that marine diesel engines are not
considered to be remanufactured if the rebuilding process falls short
of this definition (i.e., the cylinder liners are removed and replaced
over more than a five-year period). As with locomotives, remanufactured
marine diesel engines are new until they are sold or placed into
service.

    For the purpose of this program, ``replace'' includes removing,
inspecting, and requalifying a liner. This addresses the situation in
which an engine experiences a cylinder failure prior to a scheduled
rebuild: The owner might replace the failed cylinder right away and
replace the others at rebuild; then, at the time of rebuild, the
installer would likely inspect the cylinder that was a few months old
to make sure it qualified for continued use according to the
certificate holder's instructions. We do not think that owners will
fail to requalify cylinders to avoid the remanufacture requirements
because requalification is done both to ensure the continued
reliability and durability of the engine and as part of surveys
necessary to retain vessel certification for safety and other purposes.
The five-year provision was first adopted in the locomotive program to
help ensure that the standards are not avoided through phased
remanufacturing (i.e., not replacing the power assemblies all at once).
It is reasonable to use this approach in the marine sector as most
commercial engines are rebuilt all at once, although some owners may
choose a rolling rebuild approach in which a certain number of
cylinders are rebuilt every year. We may revisit the five-year limit
after a few years of the program to evaluate whether this is the
appropriate period and whether owners are adjusting their rebuild
practices, particularly with respect to rolling rebuilds, to circumvent
the regulations (see discussion of rolling rebuilds, below).
    When an engine is remanufactured, it must be certified as meeting
the emission standards for remanufactured engines (by using a certified
remanufacture system) unless there is no certified remanufacturing
system available for that engine. In other words, the owner/operator or
installer of a covered engine would be required to use a certified
marine remanufacture system when remanufacturing that engine if one is
available. If there is no certified system available at that time,
there is no requirement. Availability means not only that EPA has
certified a system, but also that it can be obtained and installed in a
timely manner consistent with normal business practices. For example, a
system would generally not be considered to be available if it required
that the engine be removed from the vessel and shipped to a factory to
be remanufactured unless that is the normal rebuild process for that
engine. Similarly, a system would not be considered to be available if
the component parts are not available for purchase in the period
normally associated with a scheduled rebuild. If a certified system is
not available there is no requirement to comply with this program until
the next remanufacture, at which time the remanufacturer would need to
check again to see if a system is available. Nonavailability due to
inability to obtain parts may be demonstrated by a written record that
shows a good faith effort to obtain parts.
    Several states and localities have voluntary retrofit programs to
reduce emissions from marine diesel engines. These programs encourage
vessel owners to apply emission reduction strategies in return for a
financial or operational incentive. Retrofit systems range from engine
adjustments to installing different cylinders, fuel injectors,
turbochargers, or other engine components. To receive the incentive,
the owner must demonstrate the reduction, often through emission
measurements. We received state agency comments expressing concern
about the potential inconsistency between state and local retrofit
programs and a potential marine remanufacture program. Specifically, a
situation could be created in which a vessel owner who has already
applied a retrofit device pursuant to a state or local retrofit program
would be required to remove the voluntary retrofit device and install a
certified marine remanufacture system. We do not want to negatively
impact the positive benefits that arise from state and local retrofit
programs, especially in those cases in which the retrofit achieves a
greater reduction (e.g., retrofit of a SCR system) than a certified
marine remanufacture system. We also do not want to discourage these
programs especially in early years where states and local programs may
achieve reductions before certified remanufacture systems become
available.
    Therefore, we are adopting a provision that will allow an owner/
operator of an engine that is fit with a retrofit device prior to 2017
pursuant to a state or local retrofit program to request a qualified
exemption from the marine remanufacture requirements for that engine.
This qualified exemption will be available only to engines equipped
with retrofit device under a state or local program before 2017. The
owner/operator must request the exemption prior to a remanufacturing
event that would otherwise trigger the requirement to use a certified
remanufacture system. The request must include documentation that the
vessel has been retrofit pursuant to a state or local retrofit program
and a signed statement declaring that to be true. Except for the
initial request for a specific vessel and a specific retrofit, a
request would be considered to be approved unless we notify the
requestor otherwise within 30 days of the date that we receive the
request. Note that the exemption does not apply where the sponsoring
government specifies that inclusion in the retrofit program is not
intended to provide an exemption from the requirements of this subpart.
EPA's granting of the exemption is conditioned upon the owner/
operator's continued use and maintenance of the retrofit kit that
provides the basis for the exemption.
    Beginning in 2017, this exemption will no longer be available for
new retrofits. Engines included in state or local retrofit programs
will be required to use a certified remanufacture system if one is
available when the engine is remanufactured. In this case either the
certified remanufacture system would be part of the retrofit or the
vessel owner would use a certified remanufacture system the next time
at the next remanufacture event.
    At this time, we are adopting standards for remanufacture systems
only for marine diesel engines over 600 kW. This 600 kW threshold is
reasonable because of the long hours of use, often at high load, of
engines above 600 kW, and their long services lives. These engines are
also more likely to undergo regular full overhauls, returning them to
as-new condition. Commercial marine diesel engines larger than 600 kW
typically undergo periodic full, like-new rebuilds. These large engines
are often installed on tugs, towboats, ferries, offshore supply
vessels, lakers, and coasters, which require reliable power at all
times. These vessels are often used for ten or more hours a day, every
day of the year. As a result, these engines are typically subject to
regular maintenance to ensure their dependability. In addition, many
manufacturers provide guidance for a full rebuild to as-new condition.
This might include replacing piston rings, heads, bearings, and gear
train/camshaft as well as piston liners.\128\ Rebuilding to as-new
condition helps ensure smooth operation over the full maintenance
interval. Owners of these vessels are also motivated to maintain their
engines because it is very complicated and expensive to repower their
vessels; replacing an engine may require major hull modifications.
Because these vessels operate for decades, often 40 or

more years, their engines may be remanufactured to as-new condition
anywhere from three to six or even more times before the vessel is
scrapped.
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    \128\ See Note from Amy Kopin, Mechanical Engineer, to Jean
Marie Revelt, EPS, Re: Marine Remanufacture Program. A copy of this
Note is available in Docket OAR-2003-0190.
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    We are not setting standards for marine remanufacture systems for
engines below 600 kW because we currently do not have sufficient data
to determine the extent that rebuilding of engines below 600kW
qualifies as remanufacturing to an as new condition. Smaller commercial
engines under 600 kW or recreational engines typically have shorter
useful lives than the larger engines and do not see as much wear on an
annual basis. This means it takes longer to acquire the hours between
maintenance intervals. Engines on some smaller commercial or
recreational marine vessels may not be rebuilt at all but, instead, are
replaced or the vessel is scrapped. There may also be other
technological and cost issues with applying remanufacture requirements
to smaller commercial or recreational engines.
    For these reasons, we are finalizing only standards for
remanufactured commercial marine diesel engines above 600 kW. We may
revisit this approach after implementing the program to evaluate
whether other remanufactured marine diesel engines should be included
in the program as well.
    A certified marine remanufacture system must achieve a 25 percent
reduction in PM emissions compared to the engine's measured baseline
emissions level (the emission level of the engine as rebuilt according
to the manufacturer's specification but before the installation of the
remanufacture system) without increasing NOX emissions
(within 5 percent). We are not finalizing a 0.22 g/kW-hr PM cap, as
proposed. The percent reduction is being adopted because the large
range of engine platforms on existing marine diesel engines makes the
selection of an effective numeric emission limit impractical. A more
stringent emission limit may prevent the development of remanufacture
systems for many engines, while a less stringent limit could allow
manufacturers to certify remanufacture systems for engines that already
meet the limit without any additional emission benefits. A percentage
reduction has the advantage of allowing more engines to participate in
the program while ensuring valid emission reductions.
    We are not adopting the multi-step approach discussed in the
proposal. This approach, based on the Urban Bus program, would have
entailed setting standards based on reductions of 60 percent, 40
percent, and 20 percent, and requiring that a rebuild use the certified
kit meeting the most stringent of these three standards if available.
Manufacturers expressed concern that such a requirement would
discourage the development of remanufacture systems since they could
rapidly become obsolete. Owners were concerned that they would be
subject to a moving requirement that would complicate their engine
maintenance and overhaul schedules and could result in identical engine
models being required to use different remanufacture systems. They also
were concerned that such an approach would mean they would have to use
a different system every time they remanufacture, and the impacts on
engines that are remanufactured over several maintenance events. For
these reasons, instead of adopting the multi-step approach, we are
adopting a single emission reduction requirement. If several certified
systems are available, we will allow any of them to be used. However,
states may develop incentive programs to encourage the use of the
certified remanufacture system with the greatest reduction. Also, we
may revisit the emission level in the future to determine if it should
be modified to reflect advances in applying new PM reduction
technologies to existing marine diesel engines.
    We expect that this PM reduction will be met by using
incrementally-improved components that are replaced when an engine is
remanufactured, based on reduction technologies manufacturers are
already using or will be using to achieve the Tier 3 PM standards. For
example, a remanufacture system could reduce PM emissions by using
different fuel injectors or different piston rings to reduce oil
consumption. Remanufacturing systems may not adversely affect engine
reliability, durability, or power.
    Some engine manufacturers expressed concern about the potential for
unintended adverse effects on engine performance, reliability, or
durability that could occur if another entity develops a remanufacture
system for their engines. They were particularly concerned about being
held responsible for an emission failure if the remanufacture system
does not perform as intended, or for an engine failure if the system
causes other engine components to fail. To address this concern, the
program we are finalizing requires any person who wishes to certify a
remanufacture system for an engine not produced by that person to
notify the original engine manufacturer and request their comments on
the remanufacture system. Any comments received by the certifier are
required to be included in the certification application, as well as a
description of how those comments were addressed.
    As we described at proposal, this final rule includes a cost cap on
marine diesel remanufacture systems of $45,000 per ton of PM reduced,
based on the incremental cost of the remanufacture system (the cost in
excess of what a rebuild would otherwise cost). This cost cap is
analogous to the reasonable cost limit in the current locomotive
remanufacturing program and is intended to ensure that marine
remanufacture systems do not impose excessively burdensome cost
requirements on vessel owners that are not justified by the benefits of
the reductions. The $45,000 per ton of PM reduced is similar to the
cost of a number of mobile source retrofit programs. This cap includes
all costs to the vessel owner associated with the remanufacture system
beyond those associated with an engine remanufactured without a
certified system, such as labor for any special installation procedures
and any modifications to the vessel or its operation (e.g., fuel
consumption impacts).
    It may not be possible for the certifier to predict the
characteristics of all vessels that can use the remanufacture system
and therefore provide a comprehensive estimate of the total incremental
costs of installing the remanufacture system. Therefore, in addition to
an estimate of the vessel-related installation costs that would apply
to most vessels, the certifier must also provide an estimate of the
amount of residual incremental costs that would be available for
installation of the remanufacture system on a particular vessel without
triggering the $45,000 per ton PM threshold (i.e., the maximum amount
installation may cost for a particular vessel after the cost of the
remanufacture system is deducted from the $45,000 maximum cost). This
will guide vessel owners in determining if the cost of a certified
remanufacture system will exceed the $45,000 threshold for a particular
vessel.
    We are including a provision that will allow a vessel owner to
request an exemption from EPA if the vessel owner can demonstrate to
EPA's satisfaction that actual installation cost for his or her vessel
will exceed the $45,000 per ton PM threshold. This may be necessary,
for example, if a vessel with external keel cooling cannot be modified
to achieve required cooling levels required by the remanufacture system
without extensive modifications to the vessel hull. We are also
including a small business exemption as well as a

financial hardship provision (see Section IV.A.13(b)(vi and vii)) that
would allow postponing the requirements for owners who can show
financial hardship.
    Marine remanufacture systems can be certified as soon as this rule
goes into effect. A remanufacture system will be considered to be
available 120 days after we issue a certificate of conformity for it or
90 days after we include it on our list of certified remanufacture
systems, whichever is later. Prior to the end of that period, a kit
will not be considered to be ``available.'' This period allows time for
owners to arrange for remanufacturing with a certified system once one
that applies to the relevant engine has been certified. Once a marine
remanufacture system is certified, as evidenced by an EPA-issued
certificate of conformity, it will be considered to be available until
it is withdrawn or the certificate holder fails to obtain a certificate
of conformity for a subsequent year. We will maintain a list of
available remanufacture systems and provide access to this list by
posting it on our website. Owners should consult the list prior to any
particular remanufacturing event to determine whether a certified
system is available and therefore whether they are affected by the
program. Uncertified systems purchased before that date can be used as
long as they are consistent with the normal parts inventory practices
of the owner or rebuild facility. Stockpiling of uncertified
remanufacture systems to evade the requirements of the program is not
allowed.
    For engines on a rolling rebuild schedule (i.e., cylinder liners
are not replaced all at once but are replaced in sets on a schedule of
5 or fewer years, for example 5 sets of 4 liners for a 20-cylinder
engine on a 5-year schedule), the requirement is triggered at the time
the remanufacture system becomes available, with the engine required to
be in a certified configuration when the last set of cylinder liners is
replaced. The remanufacturing requirements do not apply for cylinder-
liner replacements that occurred before the remanufacture system
becomes available. Any remanufacturing that occurs after the system is
available needs to use the certified system, including remanufacturing
that occurs on a rolling schedule over less than five years following
the availability of the remanufacturing system. If the components of a
certified remanufacture system are not compatible with the engine's
current configuration, the program allows the owner to postpone the
installation of the remanufacture system until the replacement of the
last set of cylinder-liners, which would occur no later than five years
after the availability of the system. At that time, all engine
components must be replaced according to the certified remanufacture
system requirements.
    Initially, we expect marine remanufacture systems to be certified
for C2 engines that are derived from certified locomotive remanufacture
systems. Some of these certified locomotive systems are already used on
C2 marine diesel engines, or can be used with modification. The new
Tier 0+, Tier 1+ and Tier 2+ certified locomotive remanufacture systems
are likely to be capable of being used on marine diesel engines without
much additional development when those certified locomotive systems
become available, for additional reductions. To encourage this
practice, we are providing a streamlined certification process for
locomotive systems certified to the new Tier 0+, Tier 1+, or Tier 2+
standards for use on C2 engines. The streamlined certification will
also be allowed for existing Tier 0 locomotive remanufacture systems
(certified under part 92), but those systems can be used only on pre-
Tier 1 (uncertified) C2 marine engines, and the use of these existing
Tier 0 systems will not be permitted after systems certified to the new
Tier 0+ (or Tier 1+ if applicable) locomotive standards are made
available. The streamlined certification process will require only an
engineering analysis demonstrating that the system would achieve
emission reductions from marine engines similar to those from
locomotives. The streamlined certification process will allow
modifications to the previously certified locomotive system as
necessary to install the system on a C2 marine engine. If the
manufacturer of a locomotive remanufacture system chooses to modify
that system in a substantive way, for example to remove NOX
emission controls (because the marine remanufacture program only
requires PM reductions), then the system will have to be recertified as
a marine remanufacture system based on measured values and subject to
all of the other certification requirements of the marine remanufacture
program (see section IV). We are not providing a similar streamlined
certification process for C1 marine systems because there are currently
no certified remanufacture systems for C1-equivalent engines through
our other mobile source programs.
    The program described above is engine-based in that it assumes that
remanufacture systems will consist of changes to engine components or
operational settings. At least one user asked EPA to consider also
allowing remanufacture systems consisting of the use of specified fuels
or fuel additives. The program we are adopting will allow this type of
remanufacture system, subject to the following constraints.
    First, the use of a remanufacture system based on a fuel or fuel
additive will not be mandatory if such a system is certified. Instead,
the use of a fuel or fuel additive system will be allowed as an
alternative compliance mechanism in place of an engine-based
remanufacture system. In other words, if an engine-based remanufacture
system is certified, owners of the affected engine models can either
use that engine-based system or use a fuel or fuel additive system if
one has also been certified; if there is no certified engine-based
system, then there is no requirement to use the fuel or fuel additive
remanufacture system. This requirement is necessary because, in
contrast to an engine-based system, a fuel or fuel additive-based
system requires positive action on the part of the owner to achieve the
emission reductions. In the case of an engine-based system, the owner
installs the replacement parts at the time of rebuild; installation of
the parts will achieve the required reductions and there is little
impact on the owner or the vessel's operations. In the case of a fuel
or fuel additive system, however, the owner will be required to use the
specified fuel or fuel additive at all times; if the owner does not
take the required action, the ``system'' will not be in use. Because a
fuel or fuel additive-based system will require the owner to do
something on a continuous basis and require additional recording and
recordkeeping, the success of the system requires a positive commitment
on behalf of the owner/operator.
    Second, the certifier of a remanufacture system based on a fuel or
fuel additive will be required to show that use of the fuel or fuel
additive meets the 25 percent PM reduction based on measured values,
without increasing NOX emissions, for all engines to which
the system will apply. This will require testing an engine with and
without the use of the specified fuel or fuel additive. Different
engines may be combined into one engine family for the purpose of
certification, based on EPA approval.
    Third, any fuel or fuel additive for which certification is sought
under the marine remanufacture program must first be registered under
40 CFR Part 79, Registration of Fuels and Fuel Additives. This is to
ensure that the fuel or fuel additive does not contain

substances that are otherwise controlled by EPA.
    Fourth, as part of the certification, the certifier will be
required to provide a sampling procedure that can be used by EPA or
other enforcement authorities to verify owner compliance onboard and
for enforcement purposes. That procedure should explain how to detect
if the appropriate level of fuel additive or if the appropriate fuel
type is actually being used onboard on the basis of a fuel sample taken
from a fuel tank on the vessel. In addition to being provided to EPA as
part of the certification process, the certifier will be required to
provide a copy of this procedure to the purchaser as part of the
remanufacture system package and will be required to maintain a copy of
the procedure on the internet to facilitate in-field compliance
verification.
    Fifth, the remanufacture system will require a notification to be
placed at the appropriate fill location (either on the fuel tank inlet
in the case of fuels or pre-blended fuel additives, or as specified on
the engine in the case of fuel additives not blended in the fuel) that
indicates the engine is outfitted with a fuel or fuel additive
remanufacture system and that compliant fuel or additives must be used
at all times.
    Finally, when an owner agrees to use a fuel or fuel additive-based
remanufacture system in lieu of an engine-based system, that owner must
also agree to any recordkeeping requirements specified in the
certification of that system. These may include keeping a record of the
purchase of the specified fuel or fuel additive and, in the case of
additives, the amounts and dates of the additive use. These
requirements must be set out by the certifier as part of the kit, and
the owner will be deemed to have agreed to them by affixing a label to
the engine or appropriate fuel or fuel additive inlet indicating that
it is certified with a fuel or fuel-additive remanufacture system.
    If an owner or operator chooses a certified remanufacture system
based on a particular fuel or fuel additive to meet these remanufacture
requirements, the failure to use the fuel or fuel additive would be a
violation of 1068.101(b)(1).
    Allowing the use of fuel or fuel additive-based remanufacture
systems is not intended to be a mechanism to require fuel switching for
marine diesel engines, either to 15 ppm fuel earlier than required or
to distillate from residual fuel for auxiliary engines on vessels with
Category 3 marine diesel engines or for those smaller vessels than may
currently use residual fuel in their C2 main propulsion engines. It is
also not intended to prevent the use of off-spec fuel in marine diesel
engines. If there is no certified engine-based remanufacture system
available for an engine, a fuel or fuel additive-based kit will not be
required to be used even if one is certified.
    EPA is committed to the development and successful operation of a
marine remanufacture program. We intend to assess the effectiveness of
this program as early as 2012 to ascertain the extent to which engine
manufacturers are providing certified remanufacture systems. If
remanufacture systems are not available or are not in the process of
being developed and certified at that time for a significant number of
engines, we may consider changes to the program. As part of that