Entities potentially affected by this action are those that manufacture, remanufacture or import locomotives or locomotive engines; and those that own or operate locomotives. Regulated categories and entities include:
Examples of potentially Category NAICS code \1\ affected entities Industry.............. 333618, 336510 Manufacturers,
remanufacturers and importers of locomotives and locomotive engines. Industry.............. 482110, 482111, Railroad owners and 482112 operators.
Industry.............. 488210 Engine repair and maintenance.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. This table lists the types of entities that EPA is now aware could potentially be regulated by this action. Other types of entities not listed in the table could also be regulated. To determine whether your company is regulated by this action, you should carefully examine the applicability criteria in 40 CFR 92.1, 1033.1, 1065.1, and 1068.1. If you have questions, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT> section.
\1\ North American Industry Classification System (NAICS).

Entities potentially affected by this action are companies and persons that manufacture, sell, or import into the United States new marine compressionignition engines, companies and persons that rebuild or maintain these engines, companies and persons that make vessels that use such engines, and the owners/operators of such vessels. Affected categories and entities include:
Examples of potentially Category NAICS code \1\ affected entities Industry.............. 333618 Manufacturers of new marine diesel engines. Industry.............. 33661 and 346611 Ship and boat building; ship building and repairing. [[Page 25099]]
Industry.............. 811310 Engine repair, remanufacture, and maintenance. Industry.............. 483 Water transportation, freight and passenger.
Industry.............. 487210 and Sightseeing
Transportation, Water. Industry.............. 4883 Support Activities for Water Transportation. Industry.............. 1141 Fishing.
Industry.............. 336612 Boat building (watercraft not built in shipyards and typically of the type suitable or intended for personal use).

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

I. Overview

A. What Is EPA Finalizing and How Does It Differ From the Proposal?

B. Why Is EPA Taking This Action?
II. Air Quality and Health Impacts

A. Overview

B. Public Health Impacts

C. Environmental Impacts

D. Other Criteria Pollutants Affected by This Final Rule

E. Emissions from Locomotive and Marine Diesel Engines III. Emission Standards

A. What Locomotives and Marine Engines Are Covered?

B. What Standards Are We Adopting?

C. Are the Standards Feasible?

IV. Certification and Compliance Program

A. Issues Common to Locomotives and Marine Engines

B. Compliance Issues Specific to Locomotives

C. Compliance Issues Specific to Marine Engines
V. Costs and Economic Impacts

A. Engineering Costs

B. Cost Effectiveness

C. EIA
VI. Benefits
VII. Alternative Program Options

A. Summary of Alternatives

B. Summary of Results
VIII. Public Participation

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132 (Federalism)

F. Executive Order 13175 (Consultation and Coordination With Indian Tribal Governments)

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and LowIncome Populations

K. Congressional Review Act
X. Statutory Provisions and Legal Authority

I. Overview

This final rule completes an important step in EPA's ongoing National Clean Diesel Campaign (NCDC) by adding new programs for locomotives and marine diesel engines to the clean diesel initiatives we have already undertaken for highway, other nonroad, and stationary diesel engines. As detailed below, it significantly strengthens the locomotive and marine diesel programs we proposed last year (72 FR 15938, April 3, 2007), especially in controlling emissions during the critical early years through the early introduction of advanced technologies and the more complete coverage of existing engines. When fully implemented, this coordinated set of new programs will reduce harmful diesel engine emissions to a small fraction of their previous levels.

The new programs address all types of diesel locomotives line haul, switch, and passenger rail, and all types of marine diesel engines below 30 liters per cylinder displacement (hereafter referred to as ``marine diesel engines'').\2\ These engines are used to power a wide variety of vessels, from small fishing and recreational boats to large tugs and Great Lakes freighters. They are also used to generate auxiliary vessel power, including on oceangoing ships.
\2\ Marine diesel engines at or above 30 liters per cylinder, called Category 3 engines, are typically used for propulsion power on oceangoing 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>).

Emissions of fine particulate matter (PM2.5>) and nitrogen oxides (NOX>) from these diesel engines contribute to nonattainment of the National Ambient Air Quality Standards (NAAQS) for PM2.5> and ozone. Today, locomotives and marine diesel engines account for about 20 percent of mobile source NOX> emissions and 25 percent of mobile source diesel PM2.5> emissions in the U.S. Absent this final action, by 2030 the relative contributions of NOX> and PM2.5> from these engines would have grown to 35 and 65 percent, respectively.

We are finalizing a comprehensive threepart program to address this problem. First, we are adopting stringent emission standards for existing locomotives and for existing commercial marine diesel engines above 600 kilowatt (kW) (800 horsepower (hp)). These standards apply when the engines are remanufactured. This part of the program will take effect as soon as certified remanufacture systems are available, for some engines as early as a few months from now. Under our existing program, locomotives have been certified to one of three tiers of standards: Tier 0 for locomotives originally built between 1973 and 2001, Tier 1 for those built between 2002 and 2004, and Tier 2 for those built in or after 2005. Under this new program, certified locomotive remanufacture systems must be made available by 2010 for Tier 0 and Tier 1 locomotives, and by 2013 for Tier 2 locomotives. Remanufacture systems that are certified for use in marine engine remanufactures are likewise required to be used. We are not, however, setting a specific compliance date for certified marine diesel remanufacture systems because we expect that engine manufacturers will be well motivated by the market opportunity to certify emissions compliant systems.

Second, we are adopting a set of nearterm emission standards, referred to as Tier 3, for newlybuilt locomotives and marine engines. The Tier 3 standards reflect the application of technologies to reduce engineout particulate matter (PM) and NOX>.

Third, we are adopting longerterm standards, referred to as Tier 4, for newlybuilt locomotives and marine
[[Page 25100]]
engines. Tier 4 standards reflect the application of highefficiency catalytic aftertreatment technology enabled by the availability of ultralow sulfur diesel fuel (ULSD). These standards take effect in 2015 for locomotives, and phase in over time for marine engines, beginning in 2014. Finally, we are adopting provisions in all three parts of the program to eliminate emissions from unnecessary locomotive idling.

Locomotives and marine diesel engines designed to these Tier 4 standards will achieve PM reductions of 90 percent and NOX> reductions of 80 percent, compared to engines meeting the current Tier 2 standards. The new standards will also yield sizeable reductions in emissions of nonmethane hydrocarbons (NMHC), carbon monoxide (CO), and hazardous compounds known as air toxics. Table I1 summarizes the PM and NOX> emission reductions for the new standards compared to today's (Tier 2) emission standards; for remanufactured engines, the comparison is to the current standards for each tier of locomotives covered, and to typical unregulated levels for marine engines. Table I1.Reductions From Levels of Existing Standards PM Sector Standards tier (percent) NOX> (percent) Locomotives............................. Remanufactured Tier 0.......... 60 1520. Remanufactured Tier 1.......... 50 ........................ Remanufactured Tier 2.......... 50 ........................ Tier 3......................... 50 ........................ Tier 4......................... 90 80. All tiersidle emissions...... 50 50. Marine Diesel Engines \a\............... Remanufactured Engines......... 2560 Up to 20. Tier 3......................... 50 20. Tier 4......................... 90 80. Note:> (a) Standards vary by displacement and within power categories. Reductions indicated are typical.

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

This final rule makes a number of important changes to the program set out in our Notice of Proposed Rulemaking (NPRM). Among these are changes that will yield significantly greater overall NOX and PM reductions, especially in the critical early years of the program: The adoption of standards for remanufactured marine engines and a 2year pullahead of the Tier 4 NOX requirements for linehaul locomotives and for 20003700 kW (27604900 hp) marine engines.

The major elements of the final program are summarized below. We are also revising existing testing, certification, and compliance provisions to better ensure emissions control in use. Detailed provisions and our justifications for them are discussed in sections III and IV. Section VII of this preamble describes a number of alternatives that we considered in developing the rule. After evaluating the alternatives, we believe that our new program provides the best opportunity for achieving timely and very substantial emissions reductions from locomotive and marine diesel engines. It balances a number of key factors: (1) Achieving very significant emissions reductions as early as possible, (2) providing appropriate lead time to develop and apply advanced control technologies, and (3) coordinating requirements in this final rule with existing highway and nonroad diesel engine programs. The provisions we are finalizing that are different from the proposed program are:

Overall, our comprehensive threepart approach to setting standards for locomotives and marine diesel engines will provide very large reductions in PM, NOX, and toxic compounds, both in the nearterm (as early as 2008), and in the longterm. These reductions will be achieved in a manner that: (1) Leverages technology developments in other diesel sectors, (2) aligns well with the clean diesel fuel requirements already being implemented, and (3) provides the lead time needed to deal with the significant engineering design workload that is involved.

(1) Locomotive Emission Standards

We are setting stringent exhaust emission standards for newlybuilt and remanufactured locomotives, furthering the initiative for cleaner locomotives started in 2004 with the establishment of the ULSD locomotive fuel program, and adding this important category of engines to the highway and nonroad diesel applications already covered [[Page 25101]]

under EPA's National Clean Diesel Campaign.

Briefly, for newlybuilt linehaul locomotives we are setting a new Tier 3 PM standard of 0.10 grams per brake horsepowerhour (g/bhphr), based on improvements to existing engine designs. This standard will take effect in 2012. We are also setting new Tier 4 standards of 0.03 g/bhphr for PM and 1.3 g/bhphr for NOX, based on the evolution of highefficiency catalytic aftertreatment technologies now being developed and introduced in the highway diesel sector. The Tier 4 standards will take effect in 2015. We are requiring that
remanufactured Tier 2 locomotives meet a PM standard of 0.10 g/bhphr, based on the same engine design improvements as Tier 3 locomotives, and that remanufactured Tier 0 and Tier 1 locomotives meet a 0.22 g/bhphr PM standard. We are also requiring that remanufactured Tier 0 locomotives meet a NOX standard of 7.4 g/bhphr, the same level as current Tier 1 locomotives, or 8.0 g/bhphr if the locomotive is not equipped with a separate loop intake air cooling system. Section III provides a detailed discussion of these new standards, and section IV details improvements being made to the applicable test, certification, and compliance programs.

In setting our original locomotive emission standards in 1998, the historic pattern of transitioning older linehaul locomotives to road and yardswitcher service resulted in our making little distinction between linehaul and switch locomotives. Because of the increase in the size of new locomotives in recent years, that pattern cannot be sustained by the railroad industry, as today's 4000+ hp (3000+ kW) locomotives are poorly suited for switcher duty. Furthermore, although there is still a fairly sizeable legacy fleet of older smaller line haul locomotives that could find their way into the switcher fleet, essentially the only newlybuilt switchers put into service over the last two decades have been of radically different design, employing one to three smaller highspeed diesel engines designed for use in nonroad applications. We are establishing new standards and special certification provisions for newlybuilt and remanufactured switch locomotives that take these factors into account.

Locomotives spend a substantial amount of time idling, during which they emit harmful pollutants, consume fuel, create noise, and increase maintenance costs. We are requiring that idle controls, such as Automatic Engine Stop/Start Systems (AESS), be included on all newly built Tier 3 and Tier 4 locomotives. We also are requiring that they be installed on all existing locomotives that are subject to the new remanufactured engine standards, at the point of first remanufacture under the standards, unless already equipped with idle controls. Additional idle emissions control beyond AESS is encouraged in our program by factoring it into the certification test program. (2) Marine Engine Emission Standards

We are setting emissions standards for newlybuilt and remanufactured marine diesel engines with displacements up to 30 liters per cylinder (referred to as Category 1 and 2, or C1 and C2, engines). Newlybuilt engines subject to the new standards include those used in commercial, recreational, and auxiliary power applications, and those below 37 kW (50 hp) that were previously regulated in our nonroad diesel program.

The new marine diesel engine standards include stringent engine based Tier 3 standards for newlybuilt marine diesel engines that phase in beginning in 2009. These are followed by aftertreatmentbased Tier 4 standards for engines above 600 kW (800 hp) that phase in beginning in 2014. The specific levels and implementation dates for the Tier 3 and Tier 4 standards vary by engine size and power. This yields an array of emission standards levels and start dates that help ensure the most stringent standards feasible at the earliest possible time for each group of newlybuilt marine engines, while helping engine and vessel manufacturers implement the program in a manner that minimizes their costs for emission reductions. The new standards and implementation schedules, as well as their technological feasibility, are described in detail in section III of this preamble.

We are also adopting standards to address the considerable impact of emissions from large marine diesel engines installed in vessels in the existing fleet. These standards apply to commercial marine diesel engines above 600 kW when these engines are remanufactured, and take effect as soon as certified remanufacture systems are available. The final requirements are different from the programmatic alternative on which we sought comment in that there is no mandatory date by which marine remanufacture systems must be made available. However, systems for the larger Category 2 marine diesel engines are expected to become available at the same time as the locomotive remanufacture systems for similar engines, as early as 2008, because Category 2 marine diesel engines are often derived from locomotive engines. This new marine remanufacture program is described in more detail in section III.B(2)(b). We intend to revisit this program in the future to evaluate the extent to which remanufacture systems are being introduced into the market without a mandatory requirement, and to determine if the program should be extended to small commercial and recreational engines as well.

Taken together, the program elements described above constitute a comprehensive program that addresses the problems caused by locomotive and marine diesel emissions from both a nearterm and longterm perspective. It does this while providing for an orderly and cost effective implementation schedule for the railroads, vessel owners, manufacturers, and remanufacturers.
B. Why Is EPA Taking This Action?
(1) Locomotives and Marine Diesels Contribute to Serious Air Pollution Problems

As we discuss extensively in both the proposal and today's action, EPA strongly believes it is appropriate to take steps now to reduce future emissions from locomotive and marine diesel engines. Emissions from these engines generate significant emissions of PM2.5 and NOX that contribute to nonattainment of the National Ambient Air Quality Standards for PM2.5 and ozone. NOX is a key precursor to ozone and secondary PM formation. These engines also emit hazardous air pollutants or air toxics, which are associated with serious adverse health effects. Finally, emissions from locomotive and marine diesel engines cause harm to public welfare, including contributing to visibility impairment and other harmful environmental impacts across the U.S.

The health and environmental effects associated with these emissions are a classic example of a negative externality (an activity that imposes uncompensated costs on others). With a negative externality, an activity's social cost (the cost borne to society imposed as a result of the activity taking place) exceeds its private cost (the cost to those directly engaged in the activity). In this case, as described below and in section II, emissions from locomotives and marine diesel engines and vessels impose public health and environmental costs on society. However, these added costs are not reflected in the costs of those using
[[Page 25102]]
these engines and equipment. The current market and regulatory scheme do not correct this externality because firms in the market are rewarded for minimizing their production costs, including the costs of pollution control, and do not benefit from reductions in emissions. In addition, firms that may take steps to use equipment that reduces air pollution may find themselves at a competitive disadvantage compared to firms that do not. The emission standards that EPA is finalizing help address this market failure and reduce the negative externality from these emissions by providing a regulatory incentive for engine and locomotive manufacturers to produce engines and locomotives that emit fewer harmful pollutants and for railroads and vessel builders and owners to use those cleaner engines.

Emissions from locomotive and marine diesel engines account for substantial portions of the country's current ambient PM2.5 and NOX levels. We estimate that today these engines account for about 20 percent of mobile source NOX emissions and about 25 percent of mobile source diesel PM2.5 emissions. Under this rulemaking, by 2030, NOX emissions from these diesel engines will be reduced annually by 800,000 tons and PM2.5 emissions by 27,000 tons, and these reductions will grow beyond 2030 as fleet turnover to the cleanest engines continues.

EPA has already taken steps to bring emissions levels from highway and nonroad diesel vehicles and engines to very low levels over the next decade, while the per horsepowerhour emission levels for locomotive and marine diesel engines remain at much higher levels comparable to the emissions for highway trucks in the early 1990s.

Both ozone and PM2.5 contribute to serious public health problems, including premature mortality, aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions and emergency room visits, school absences, loss work days, and restricted activity days), changes in lung function and increased respiratory symptoms, altered respiratory defense mechanisms, and chronic bronchitis. Diesel exhaust is of special public health concern, and since 2002 EPA has classified exposure to diesel exhaust as likely to be carcinogenic to humans by inhalation from environmental exposures.\4\ Recent studies are showing that populations living near large diesel emission sources such as major roadways, rail yards, and marine ports are likely to experience greater diesel exhaust exposure levels than the overall U.S. population, putting them at greater health risks.\5 6\
\4\ U.S. EPA (2002) Health Assessment Document for Diesel Engine Exhaust. EPA/600/890/057F. Office of Research and Development, Washington DC. This document is available electronically at http:// cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
\5\ Kinnee, E.J.; Touman, J.S.; Mason, R.; Thurman, J.; Beidler, A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile emissions to road segments for air toxics modeling in an urban area. Transport. Res. Part D 9: 139150.
\6\ State of California Air Resources Board. Roseville Rail Yard Study. Stationary Source Division, October 14, 2004. This document is available electronically at: http://www.arb.ca.gov/diesel/ documents/rrstudy.htm and State of California Air Resources Board. Diesel Particulate Matter Exposure Assessment Study for the Ports of Los Angeles and Long Beach, April 2006. This document is available electronically at: http://www.arb.ca.gov/regact/marine2005/ portstudy0406.pdf.

EPA recently conducted an initial screeninglevel analysis \7\ of selected marine port areas and rail yards to better understand the populations that are exposed to diesel particulate matter (DPM) emissions from these facilities.^{8 9} This screeninglevel analysis focused on a representative selection of national marine ports and rail yards.\10\ Of the 47 marine ports and 37 rail yards selected, the results indicate that at least 13 million people, including a disproportionate number of lowincome households, AfricanAmericans, and Hispanics, living in the vicinity of these facilities, are being exposed to ambient DPM levels that are 2.0 [mu]g/m³ and 0.2 [mu]g/m³ above levels found in areas further from these facilities. Because those populations exposed to DPM emissions from marine ports and rail yards are more likely to be lowincome and minority residents, these populations will benefit from the controls being finalized in this action. The detailed findings of this study are available in the public docket for this rulemaking.
\7\ This type of screeninglevel analysis is an inexact tool and not appropriate for regulatory decisionmaking; it is useful in beginning to understand potential impacts and for illustrative purposes. Additionally, the emissions inventories used as inputs for the analyses are not official estimates and likely underestimate overall emissions because they are not inclusive of all emission sources at the individual ports in the sample. For example, most inventories included emissions from oceangoing vessels (powered by Category 3 engines), as well as some commercial vessel categories, including harbor crafts, (powered by Category 1 and 2 engines), cargo handling equipment, locomotives, and heavyduty vehicles. This final rule will not address emissions from oceangoing vessels, cargo handling equipment or heavyduty vehicles.
\8\ ICF International. September 28, 2007. Estimation of diesel particulate matter concentration isopleths for marine harbor areas and rail yards. Memorandum to EPA under Work Assignment Number 03, Contract Number EPC06094. This memo is available in Docket EPA HQOAR20030190.
\9\ ICF International. September 28, 2007. Estimation of diesel particulate matter population exposure near selected harbor areas and rail yards. Memorandum to EPA under Work Assignment Number 03, Contract Number EPC06094. This memo is available in Docket EPA HQOAR20030190.
\10\ The Agency selected a representative sample of the top 150 U.S. ports including coastal, inland, and Great Lake ports. In selecting a sample of rail yards the Agency identified a subset from the hundreds of rail yards operated by Class I Railroads.

Today, millions of Americans continue to live in areas that do not meet existing air quality standards. Currently, ozone concentrations exceeding the 8hour ozone NAAQS occur over wide geographic areas, including most of the nation's major population centers. As of October 10, 2007, approximately 88 million people live in 39 designated areas (which include all or part of 208 counties) that either do not meet the current PM2.5 NAAQS or contribute to violations in other counties, and 144 million people live in 81 areas (which include all or part of 368 counties) designated as not in attainment for the 8hour ozone NAAQS. These numbers do not include the people living in areas where there is a significant future risk of failing to maintain or achieve either the current or future PM2.5 or ozone NAAQS.

In addition to public health impacts, there are public welfare and environmental impacts associated with ozone and PM2.5 emissions. Ozone causes damage to vegetation which leads to crop and forestry economic losses, as well as harm to national parks, wilderness areas, and other natural systems. NOX and direct emissions of PM2.5 can contribute to the impairment of visibility in many parts of the U.S., where people live, work, and recreate, including national parks, wilderness areas, and mandatory class I federal areas. The deposition of airborne particles can also reduce the aesthetic appeal of buildings and culturally important objects through soiling and can contribute directly (or in conjunction with other pollutants) to structural damage by means of corrosion or erosion. Finally, NOX emissions from diesel engines contribute to the acidification, nitrification, and eutrophication of water bodies.

While EPA has already adopted many emission control programs that are expected to reduce ambient ozone and PM2.5 levels, including the Clean Air Interstate Rule (CAIR) (70 FR 25162, May 12, 2005) and the Clean Air Nonroad Diesel Rule (69 FR 38957, June 29, 2004), the Heavy Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements (66 FR 5002, Jan. 18, 2001), and the Tier 2 Vehicle and Gasoline Sulfur Program
[[Page 25103]]
(65 FR 6698, Feb. 10, 2000), the additional PM2.5 and NOX emission reductions resulting from this rule will assist states in attaining and maintaining the Ozone and the PM2.5 NAAQS both near term and in the decades to come.

In September 2006, EPA finalized revised PM2.5 NAAQS standards and over the next few years the EPA will undergo the process of designating areas that do not meet this new standard. EPA modeling, conducted as part of finalizing the revised NAAQS, projects that in 2015 up to 52 counties with 53 million people may violate either the daily or annual standards for PM2.5 (or both), while an additional 27 million people in 54 counties may live in areas that have air quality measurements within 10 percent of the revised NAAQS. Even in 2020 up to 48 counties, with 54 million people, may still not be able to meet the revised PM2.5 NAAQS and an additional 25 million people, living in 50 counties, are projected to have air quality measurements within 10 percent of the revised standards. The locomotive and marine diesel PM2.5 reductions resulting from this rulemaking are needed by a number of states to both attain and maintain the revised PM2.5 NAAQS.

State and local governments continue working to protect the health of their citizens and comply with requirements of the Clean Air Act (CAA or ``the Act''). As part of this effort they recognize the need to secure additional major reductions in both diesel PM2.5 and NOX emissions by undertaking numerous statelevel actions.11 However, they have also urged Agency action to finalize a strong locomotive and marine diesel engine program that will provide crucial emission reductions both in the near and longterm. \11\ Two examples of state and local actions are: California Air Resources Board (2006). Emission Reduction Plan for Ports and Goods Movements (April 2006), Available electronically at www.arb.ca.gov/ gmp/docs/finalgmpplan090905.pdf; Connecticut Department of Environmental Protection (2006). Connecticut's Clean Diesel Plan (January 2006). See http://www.dep.state.ct.us/air2/diesel/index.htm for description of initiative.

The federal program finalized today results in earlier and significantly greater NOX and PM reductions from the locomotive and marine sector than the proposed program because of the firstever national standards for remanufactured marine engines and the starting of Tier 4 NOX requirements for linehaul locomotives and for 20003700 kW (27604900 hp) marine engines two years earlier than proposed. These changes reflect important cooperative efforts by the regulated industry to implement cleaner technology as early as possible. While the program finalized today will help many states and communities achieve cleaner air, for some areas, such as the South Coast of California, the reductions achieved through this rule will not alone enable them to meet their nearterm ozone and PM air quality goals. This was also the case for our 1998 locomotive rulemaking, where the State of California worked with Class I railroads operating in southern California to develop a Memoranda of Understanding (MOU) ensuring that the cleanest technologies enabled by federal rules were expeditiously introduced in areas of California with greatest air quality improvement needs. EPA continues to support California's efforts to reconcile likely future growth in the locomotive and marine sector with the public health protection needs of the area, and today's final rule includes provisions which are well suited to encouraging early deployment of cleaner technologies through the development of similar programs.

In addition to these new standards, EPA has a number of voluntary programs that help enable government, industry, and local communities to address challenging air quality problems. The EPA SmartWay program has worked with railroads to encourage them to reduce unnecessary locomotive idling and will continue to promote the use of innovative idle reduction technologies that can substantially reduce locomotive emissions while reducing fuel consumption. EPA's National Clean Diesel Campaign, through its Clean Ports USA program is working with port authorities, terminal operators, and trucking and rail companies to promote cleaner diesel technologies and emission reduction strategies through education, incentives, and financial assistance. Part of these efforts involves voluntary retrofit programs that can further reduce emissions from the existing fleet of diesel engines. Finally, EPA is implementing a new Sustainable Ports Strategy which will allow EPA to partner with ports, business partners, communities and other stakeholders to become world leaders in sustainability, including achieving cleaner air. This new strategy builds on the success of collaborative work EPA has been doing in partnership with the American Association of Port Authorities (AAPA), and through port related efforts of Clean Ports USA, SmartWay, EPA's Regional Diesel Collaboratives and other programs. Together these approaches augment the regulations being finalized today, helping states and communities achieve larger reductions sooner in the areas of our country that need them the most.

(2) Advanced Technologies Can Be Applied

Air pollution from locomotive and marine diesel exhaust is a challenging problem. However, we believe it can be addressed effectively through a combination of engineout emission reduction technologies and highefficiency catalytic aftertreatment technologies. As discussed in greater detail in section III.C, the development of these aftertreatment technologies for highway and nonroad diesel applications has advanced rapidly in recent years, so that new engines can achieve very large emission reductions in PM and NOX (in excess of 90 and 80 percent, respectively).

Highefficiency PM control technologies are being broadly used in many parts of the world and are being used domestically to comply with EPA's heavyduty truck standards that started taking effect in the 2007 model year. These technologies are highly durable and robust in use and have proved extremely effective in reducing exhaust hydrocarbon (HC) and carbon monoxide emissions.

Control of NOX emissions from locomotive and marine diesel engines can also be achieved with highefficiency exhaust emission control technologies. Such technologies are expected to be used to meet the stringent NOX standards included in EPA's heavyduty highway diesel and nonroad Tier 4 programs and have been in production for heavyduty trucks in Europe since 2005 and in many stationary source applications throughout the world.

Section III.C discusses additional engineering challenges in applying these technologies to newlybuilt locomotive and marine engines, as well as the development steps that we expect to be taken to resolve the challenges. With the lead time available and the assurance of ULSD for the locomotive and marine sectors in 2012, as provided by our 2004 final rule for nonroad engines and fuel, we are confident the application of advanced technology to locomotives and marine diesel engines will proceed at a reasonable rate of progress and will result in systems capable of achieving the new standards on time.

(3) Basis for Action Under the Clean Air Act

Authority for the actions promulgated in this document is granted to the EPA
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by sections 114, 203, 205, 206, 207, 208, 213, 216, and 301(a) of the Clean Air Act as amended in 1990 (42 U.S.C. 7414, 7522, 7524, 7525, 7541, 7542, 7547, 7550 and 7601(a)).

Authority to Set Standards. EPA is promulgating emissions standards for new marine diesel engines pursuant to its authority under section 213(a)(3) and (4) of the CAA. EPA is promulgating emission standards for new locomotives and new engines used in locomotives pursuant to its authority under section 213(a)(5) of the CAA.

EPA has previously determined that certain existing locomotive engines, when they are remanufactured, are returned to asnew condition and are expected to have the same performance, durability, and reliability as freshlymanufactured locomotive engines. Consequently we set emission standards for these remanufactured engines that apply at the time of remanufacture (defined as ``to replace, or inspect and qualify, each and every power assembly of a locomotive or locomotive engine, whether during a single maintenance event or cumulatively within a fiveyear period * * *'' (see 61 FR 53102, October 4, 1996; 40 CFR 92.2). In this action we are adopting new tiers of standards for both freshly manufactured and remanufactured locomotives and locomotive engines.

In the proposal for this rulemaking we also discussed applying a similar approach to marine diesel engines. Many marine diesel engines, particularly those above 600 kW (800 hp), periodically undergo a maintenance process that returns them to asnew condition. A full rebuild that brings an engine back to asnew condition includes a complete overhaul of the engine, including piston, rings, liners, turbocharger, heads, bearings, and geartrain/camshaft removal and replacement. Engine manufacturers typically provide instructions for such a full rebuild. Marine diesel engine owners complete this process to maintain engine reliability, durability, and performance over the life of their vessel, and to avoid the need to repower (replace the engine) before their vessel wears out. A commercial marine vessel can be in operation in excess of 40 years, which means that a marine diesel engine may be remanufactured to asnew condition three or more times before the vessel is scrapped.

Because these remanufactured engines are returned to asnew condition, section 213(a)(3) and (4) give EPA the authority to set emission standards for those engines. We are adopting requirements for remanufactured marine diesel engines, described in section III.B(2)(b) of this action. For the purpose of this program, we are defining remanufacture as the replacement of all cylinder liners, either in one maintenance event or over the course of five years (for the purpose of this program, ``replacement'' includes the removing, inspecting and requalifying a liner). While replacement of cylinder liners is only one element of a full rebuild, it is common to all rebuilds. Marine diesel engines that do not have their cylinder liners replaced all at once or within a fiveyear period, or that do not perform cylinder liner replacement at all, are not considered to be returned to asnew condition and therefore are not considered to be remanufactured. Those engines will not be subject to the marine remanufacture requirements.

Pollutants That Can Be Regulated. CAA section 213(a)(3) directs the Administrator to set NOX, volatile organic compounds (VOCs), or carbon monoxide standards for classes or categories of engines such as marine diesel engines that contribute to ozone or carbon monoxide concentrations in more than one nonattainment area. These (``standards shall achieve the greatest degree of emission reduction achievable through the application of technology which the Administrator determines will be available for the engines or vehicles, giving appropriate consideration to cost, lead time, noise, energy, and safety factors associated with the application of such technology.''

CAA section 213(a)(4) authorizes the Administrator to establish standards to control emissions of pollutants which ``may reasonably be anticipated to endanger public health and welfare'' where the Administrator determines, as it has done for emissions of PM, that nonroad engines as a whole contribute significantly to such air pollution. The Administrator may promulgate regulations that are deemed appropriate, taking into account costs, noise, safety, and energy factors, for classes or categories of new nonroad vehicles and engines which cause or contribute to such air pollution.

Level of the Standards. CAA section 213(a)(5) directs EPA to adopt emission standards for new locomotives and new engines used in locomotives that achieve the ``greatest degree of emissions reductions achievable through the use of technology that the Administrator determines will be available for such vehicles and engines, taking into account the cost of applying such technology within the available time period, the noise, energy, and safety factors associated with the applications of such technology.'' Section 213(a)(5) does not require any review of the contribution of locomotive emissions to pollution, though EPA does provide such information in this rulemaking. As described in section III of this preamble and in chapter 4 of the final Regulatory Impact Analysis (RIA), EPA has evaluated the available information to determine the technology that will be available for locomotives and engines subject to EPA standards.

Certification and Implementation. EPA is also acting under its authority to implement and enforce both the marine diesel emission standards and the locomotive emission standards. Section 213(d) provides that the standards EPA adopts for both new locomotive and marine diesel engines ``shall be subject to sections 206, 207, 208, and 209'' of the Clean Air Act, with such modifications that the Administrator deems appropriate to the regulations implementing these sections. In addition, the locomotive and marine standards ``shall be enforced in the same manner as [motor vehicle] standards prescribed under section 202'' of the Act. Section 213(d) also grants EPA authority to promulgate or revise regulations as necessary to determine compliance with, and enforce, standards adopted under section 213.

Technological Feasibility and Cost of Standards. The evidence provided in section III.C of this Preamble and in chapter 4 of the RIA indicates that the stringent emission standards we are setting today for newlybuilt and remanufactured locomotive and marine diesel engines are feasible and reflect the greatest degree of emission reduction achievable through the use of technology that will be available in the model years to which they apply. We have given appropriate consideration to costs in setting these standards. Our review of the costs and costeffectiveness of these standards indicate that they will be reasonable and comparable to the costeffectiveness of other emission reduction strategies that EPA has required in prior rulemakings. We have also reviewed and given appropriate consideration to the energy factors of this rule in terms of fuel efficiency as well as any safety and noise factors associated with these standards.

Health and Environmental Need for the Standards. The information in section II of this Preamble and chapter 2 of the RIA regarding air quality and public health impacts provides strong evidence that emissions from marine diesel engines and locomotives significantly and adversely impact public health or welfare. EPA has
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already found in previous rules that emissions from new marine diesel engines contribute to ozone and carbon monoxide concentrations in more than one area which has failed to attain the ozone and carbon monoxide NAAQS (64 FR 73300, December 29, 1999). EPA has also previously determined that it is appropriate to establish PM standards for marine diesel engines under section 213(a)(4), and the additional information on the carcinogenicity of exposure to diesel exhaust noted above reinforces this finding. In addition, we have already found that emissions from nonroad engines as a whole significantly contribute to air pollution that may reasonably be anticipated to endanger public welfare due to regional haze and visibility impairment (67 FR 68241, Nov. 8, 2002). We find here, based on the information in the NPRM and in section II of this preamble and Chapters 2 and 3 of the final RIA, that emissions from the new marine diesel engines likewise contribute to regional haze and to visibility impairment.

The PM and NOX emission reductions resulting from these standards are important to states' efforts in attaining and maintaining the ozone and the PM2.5 NAAQS in the near term and in the decades to come. As noted above, the risk to human health and welfare will be significantly reduced by the standards finalized in today's action.

II. Air Quality and Health Impacts

The locomotive and marine diesel engines subject to this final rule generate significant emissions of particulate matter (PM) and nitrogen oxides (NOX) that contribute to nonattainment of the National Ambient Air Quality Standards (NAAQS) for PM2.5 and ozone. These engines also emit hazardous air pollutants or air toxics that are associated with serious adverse health effects and contribute to visibility impairment and other harmful environmental impacts across the U.S.

By 2030, these standards are expected to reduce annual locomotive and marine diesel engine PM2.5 emissions by 27,000 tons; NOX emissions by 800,000 tons; and volatile organic compound (VOC) emissions by 43,000 tons as well as reducing carbon monoxide (CO) and toxic compounds known as air toxics.\12\
\12\ Nationwide locomotive and marine diesel engines comprise approximately 3 percent of the nonroad mobile sources hydrocarbon inventory. EPA National Air Quality and Emissions Trends Report 1999. March 2001, Document Number: EPA 454/R0004. This document is available in Docket EPAHQOAR20030190. This document is available electronically at: http://www.epa.gov/air/airtrends/aqtrnd99/.

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

A. Overview

From a public health perspective, we are concerned with locomotive and marine diesel engines' contributions to atmospheric levels of particulate matter in general, diesel PM2.5 in particular, various gaseous air toxics, and ozone. Today, locomotive and marine diesel engine emissions represent a substantial portion of the U.S. mobile source diesel PM2.5 and NOX inventories, approximately 20 percent of mobile source NOX and 25 percent of mobile source diesel PM2.5. Over time, the relative contribution of these diesel engines to air quality problems is expected to increase as the emission contribution from other mobile sources decreases and the usage of locomotives and marine vessels increases. By 2030, without the additional emissions controls finalized in today's rule, locomotive and marine diesel engines will emit about 65 percent of the total mobile source diesel PM2.5 emissions and 35 percent of the total mobile source NOX emissions.

Based on the most recent data available for this rule, air quality problems continue to persist over a wide geographic area of the United States. As of October 10, 2007 there are approximately 88 million people living in 39 designated areas (which include all or part of 208 counties) that either do not meet the current PM2.5 NAAQS or contribute to violations in other counties, and 144 million people living in 81 areas (which include all or part of 366 counties) designated as not in attainment for the 8hour ozone NAAQS. These numbers do not include the people living in areas where there is a significant future risk of failing to maintain or achieve either the current or future PM2.5 or ozone NAAQS. Figure II1 illustrates the widespread nature of these problems. This figure depicts counties which are currently designated nonattainment for either or both the 8hour ozone NAAQS and PM2.5 NAAQS. It also shows the location of mandatory class I federal areas for visibility.
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The engine standards finalized in this rule will help reduce emissions of PM, NOX, VOCs, CO, and air toxics and their associated health and environmental effects. Emissions from locomotives and diesel marine engines contribute to PM and ozone concentrations in many, if not all, of these nonattainment areas.\13\ The engine standards being finalized today will become effective as early as 2008, making the expected PM2.5, NOX, and VOC inventory reductions from this rulemaking critical to a number of states as they seek to either attain or maintain the current PM2.5 or ozone NAAQS. \13\ See section II.B.(1)(c) and II.B.(2)(c) for a summary of the impact emission reductions from locomotive and marine diesel engines will have on air quality in current PM2.5 and ozone nonattainment areas.

Beyond the impact locomotive and marine diesel engines have on our nation's ambient air quality the diesel
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exhaust emissions from these engines are also of particular concern since exposure to diesel exhaust is classified as likely to be carcinogenic to humans by inhalation from environmental levels of exposure.\14\ Many people spend a large portion of time in or near areas of concentrated locomotive or marine diesel emissions, near rail yards, marine ports, railways, and waterways. Recent studies show that populations living near large diesel emission sources such as major roadways,\15\ rail yards \16\ and marine ports \17\ are likely to experience greater diesel exhaust exposure levels than the overall U.S. population, putting them at a greater health risk.
\14\ U.S. EPA (2002) Health Assessment Document for Diesel Engine Exhaust. EPA/600/890/057F. Office of Research and
Development, Washington, DC. This document is available in Docket EPAHQOAR20030190. This document is available electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060. \15\ Kinnee, E.J.; Touma, J.S.: Mason, R.; Thurman, J.; Beidler, A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile emissions to road segments for air toxics modeling in an urban area. Transport. Res. Part D 9:139150; also see Cohen, J.; Cook, R; Bailey, C.R.; Carr, E. (2005) Relationship between motor vehicle emissions of hazardous pollutants, roadway proximity, and ambient concentrations in Portland, Oregon. Environ. Modeling & Software 20: 712.
\16\ Hand, R.; Di, P; Servin, A.; Hunsaker, L.; Suer, C. (2004) Roseville Rail Yard Study. California Air Resources Board. This document is available in Docket EPAHQOAR20030190. [Online at http://www.arb.ca.gov/diesel/documents/rrstudy.htm]. \17\ Di P.; Servin, A.; Rosenkranz, K.; Schwehr, B.; Tran, H. (April 2006); Diesel Particulate Matter Exposure Assessment Study for the Ports of Los Angeles and Long Beach. State of California Air Resources Board.

EPA recently conducted an initial screeninglevel analysis \18\ of selected marine port areas and rail yards to better understand the populations that are exposed to diesel particulate matter (DPM) emissions from these facilities.^{19 20} This screeninglevel analysis focused on a representative selection of national marine ports and rail yards.\21\ Of the 47 marine ports and 37 rail yards selected, the results indicate that at least 13 million people, including a disproportionate number of lowincome households, AfricanAmericans, and Hispanics, living in the vicinity of these facilities, are being exposed to ambient DPM levels that are 2.0 [mu]g/m³ and 0.2 [mu]g/m³ above levels found in areas further from these facilities. Because those populations exposed to DPM emissions from marine ports and rail yards are more likely to be lowincome and minority residents, these populations will benefit from the controls being finalized in this action. The detailed findings of this study are available in the public docket for this rulemaking.
\18\ This type of screeninglevel analysis is an inexact tool and not appropriate for regulatory decisionmaking; it is useful in beginning to understand potential impacts and for illustrative purposes. Additionally, the emissions inventories used as inputs for the analyses are not official estimates and likely underestimate overall emissions because they are not inclusive of all emission sources at the individual ports in the sample. For example, most inventories included emissions from oceangoing vessels (powered by Category 3 engines), as well as some commercial vessel categories, including harbor crafts (powered by Category 1 and 2 engines), cargo handling equipment, locomotives, and heavyduty vehicles. This final rule will not address emissions from oceangoing vessels, cargo handling equipment or heavyduty vehicles.
\19\ ICF International. September 28, 2007. Estimation of diesel particulate matter concentration isopleths for marine harbor areas and rail yards. Memorandum to EPA under Work Assignment Number 03, Contract Number EPC06094. This memo is available in Docket EPA HQOAR20030190.
\20\ ICF International. September 28, 2007. Estimation of diesel particulate matter population exposure near selected harbor areas and rail yards. Memorandum to EPA under Work Assignment Number 03, Contract Number EPC06094. This memo is available in Docket EPA HQOAR20030190.
\21\ The Agency selected a representative sample of the top 150 U.S. ports including coastal, inland and Great Lake ports. In selecting a sample of rail yards the Agency identified a subset from the hundreds of rail yards operated by Class I Railroads.

In the following sections we review important public health effects linked to pollutants emitted from locomotive and marine diesel engines. First, the human health effects caused by the pollutants and their current and projected ambient levels are discussed. Following the discussion of health effects, the modeled air quality benefits resulting from this action and the welfare effects associated with emissions from diesel engines are presented. Finally, the locomotive and marine engine emission inventories for the primary pollutants affected by this rule are provided. In summary, the emission reductions from this rule will contribute to controlling the health and welfare problems associated with ambient PM and ozone levels and with diesel related air toxics.

Taken together, the materials in this section and in the proposal describe the need for tightened emission standards for both locomotive and marine diesel engines and the air quality and public health benefits resulting from this program. This section is not an exhaustive treatment of these issues. For a fuller understanding of the topics treated here, you should refer to the extended presentations in Chapter 2, 3 and 5 of the Regulatory Impact Analysis (RIA) accompanying this final rule.
B. Public Health Impacts

(1) Particulate Matter

The locomotive and marine engine standards detailed in this action will result in significant reductions in primary (directly emitted) PM2.5 emissions. In addition, the standards finalized today will reduce emissions of NOX and VOCs, which contribute to the formation of secondary PM2.5. Locomotive and marine diesel engines emit high levels of NOX, which react in the atmosphere to form secondary PM2.5 (namely ammonium nitrate). These engines also emit SO2 and VOC, which react in the atmosphere to form secondary PM2.5 composed of sulfates and organic carbonaceous PM2.5. This rule will reduce both primary and secondary PM.

(a) Background

Particulate matter (PM) represents a broad class of chemically and physically diverse substances. It can be principally characterized as discrete particles that exist in the condensed (liquid or solid) phase spanning several orders of magnitude in size. PM is further described by breaking it down into size fractions. PM10 refers to particles generally less than or equal to 10 micrometers ([mu]m) in diameter. PM2.5 refers to fine particles, generally less than or equal to 2.5 [mu]m in diameter. Inhalable (or ``thoracic'') coarse particles refer to those particles generally greater than 2.5 [mu]m but less than or equal to 10 [mu]m in diameter. Ultrafine PM refers to particles less than 100 nanometers (0.1 [mu]m) in diameter. Larger particles tend to be removed by the respiratory clearance mechanisms (e.g. coughing), whereas smaller particles are deposited deeper in the lungs.

Fine particles are produced primarily by combustion processes and by transformations of gaseous emissions (e.g., SOx, NOX and VOC) in the atmosphere. The chemical and physical properties of PM2.5 may vary greatly with time, region, meteorology, and source category. Thus, PM2.5 may include a complex mixture of different pollutants including sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These particles can remain in the atmosphere for days to weeks and travel hundreds to thousands of kilometers.

The primary PM2.5 NAAQS includes a shortterm (24hour) and a longterm (annual) standard. The 1997 PM2.5 NAAQS established by EPA set the 24hour standard at a level of 65 [mu]g/ m³ based on the 98th percentile concentration averaged over three years. The annual standard specifies an
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expected annual arithmetic mean not to exceed 15 [mu]g/m³ averaged over three years.

EPA has recently amended the NAAQS for PM2.5 (71 FR 61144, October 17, 2006). The final rule, signed on September 21, 2006, addressed revisions to the primary and secondary NAAQS for PM to provide increased protection of public health and welfare, respectively. The level of the 24hour PM2.5 NAAQS was revised from 65 [mu]g/m³ to 35 [mu]g/m³ and the level of the annual PM2.5 NAAQS was retained at 15 [mu]g/ m³. With regard to

FOR FURTHER INFORMATION CONTACT John Mueller, U.S. EPA, Office of Transportation and Air Quality, Assessment and Standards Division (ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; telephone number: (734) 2144275; fax number: (734) 2144816; email address: Mueller.John@epa.gov,> or Assessment and Standards Division Hotline; telephone number: (734) 2144636.