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

Part IV

Environmental Protection Agency

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40 CFR Parts 9, 85, et al.

Control of Emissions of Air Pollution From Locomotive Engines and

Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder;

Republication; Final Rule

Federal Register / Vol. 73, No. 126 / Monday, June 30, 2008 / Rules

and Regulations

[[Page 37096]]

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ENVIRONMENTAL PROTECTION AGENCY

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

1068

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

RIN 2060-AM06

Control of Emissions of Air Pollution From Locomotive Engines and

Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder;

Republication

Editorial Note: FR Doc. E8-7999 was originally published at

pages 25098 to 25352 in the issue of Tuesday, May 6, 2008. This

document included numerous typographical and other errors that were

inadvertently introduced in the printing process. Because of the

number of errors, this document is being republished in its

entirety. This republication does not change the effective date of

the original document.

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is adopting a comprehensive program to dramatically reduce

pollution from locomotives and marine diesel engines. The controls will

apply to all types of locomotives, including line-haul, switch, and

passenger, and all types of marine diesel engines below 30 liters per

cylinder displacement, including commercial and recreational,

propulsion and auxiliary. The near-term emission standards for newly-

built engines will phase in starting in 2009. The near-term program

also includes new emission limits for existing locomotives and marine

diesel engines that apply when they are remanufactured, and take effect

as soon as certified remanufacture systems are available, as early as

2008. The long-term emissions standards for newly-built locomotives and

marine diesel engines are based on the application of high-efficiency

catalytic aftertreatment technology. These standards begin to take

effect in 2015 for locomotives and in 2014 for marine diesel engines.

We estimate particulate matter (PM) reductions of 90 percent and

nitrogen oxides (NOX) reductions of 80 percent from engines

meeting these standards, compared to engines meeting the current

standards.

We project that by 2030, this program will reduce annual emissions

of NOX and PM by 800,000 and 27,000 tons, respectively. EPA

projects these reductions will annually prevent up to 1,100 PM-related

premature deaths, 280 ozone-related premature deaths, 120,000 lost work

days, 120,000 school day absences, and 1.1 million minor restricted-

activity days. The annual monetized health benefits of this rule in

2030 will range from $9.2 billion to $11 billion, assuming a 3 percent

discount rate, or between $8.4 billion to $10 billion, assuming a 7%

discount rate. The estimated annual social cost of the program in 2030

is projected to be $740 million, significantly less than the estimated

benefits.

DATES: This rule is effective on July 7, 2008. The incorporation by

reference of certain publications listed in this regulation is approved

by the Director of the Federal Register as of July 7, 2008.

ADDRESSES: EPA has established a docket for this action under Docket ID

No. EPA-HQ-2003-0190. All documents in the docket are listed on the

www.regulations.gov web site. Although listed in the index, some

information is not publicly available, e.g., CBI or other information

whose disclosure is restricted by statute. Certain other material, such

as copyrighted material, is not placed on the Internet and will be

publicly available only in hard copy form. Publicly available docket

materials are available either electronically through

www.regulations.gov or in hard copy at the Air Docket, EPA/DC, EPA

West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. The

Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through

Friday, excluding legal holidays. The telephone number for the Public

Reading Room is (202) 566-1744, and the telephone number for the Air

Docket is (202) 566-1742.

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) 214-4275; fax number: (734)

214-4816; e-mail address: [email protected], or Assessment and

Standards Division Hotline; telephone number: (734) 214-4636.

SUPPLEMENTARY INFORMATION:

Does This Action Apply to Me?

Locomotives

Entities potentially affected by this action are those that

manufacture, remanufacture or import locomotives or locomotive engines;

and those that own or operate locomotives. Regulated categories and

entities include:

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Examples of potentially

Category NAICS code \1\ affected entities

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Industry.............. 333618, 336510 Manufacturers,

remanufacturers and

importers of locomotives and

locomotive engines.

Industry.............. 482110, 482111, Railroad owners and

482112 operators.

Industry.............. 488210 Engine repair and

maintenance.

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This table is not intended to be exhaustive, but rather provides a

guide for readers regarding entities likely to be regulated by this

action. This table lists the types of entities that EPA is now aware

could potentially be regulated by this action. Other types of entities

not listed in the table could also be regulated. To determine whether

your company is regulated by this action, you should carefully examine

the applicability criteria in 40 CFR 92.1, 1033.1, 1065.1, and 1068.1.

If you have questions, consult the person listed in the preceding FOR

FURTHER INFORMATION CONTACT section.

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\1\ North American Industry Classification System (NAICS).

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Marine Engines and Vessels

Entities potentially affected by this action are companies and

persons that manufacture, sell, or import into the United States new

marine compression-ignition engines, companies and persons that rebuild

or maintain these engines, companies and persons that make vessels that

use such engines, and the owners/operators of such vessels. Affected

categories and entities include:

[[Page 37097]]

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Examples of potentially

Category NAICS code \1\ affected entities

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Industry.............. 333618 Manufacturers of new marine

diesel engines.

Industry.............. 33661 and 346611 Ship and boat building; ship

building and repairing.

Industry.............. 811310 Engine repair, remanufacture,

and maintenance.

Industry.............. 483 Water transportation, freight

and passenger.

Industry.............. 487210 and Sightseeing

Transportation, Water.

Industry.............. 4883 Support Activities for Water

Transportation.

Industry.............. 1141 Fishing.

Industry.............. 336612 Boat building (watercraft not

built in shipyards and

typically of the type

suitable or intended for

personal use).

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This table is not intended to be exhaustive, but rather provides a

guide for readers regarding entities likely to be regulated by this

action. This table lists the types of entities that EPA is now aware

could potentially be regulated by this action. Other types of entities

not listed in the table could also be regulated. To determine whether

your company is regulated by this action, you should carefully examine

the applicability criteria in 40 CFR 94.1, 1042.1, 1065.1, and 1068.1.

If you have questions, consult the person listed in the preceding FOR

FURTHER INFORMATION CONTACT section.

Outline of This Preamble

I. Overview

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

Proposal?

B. Why Is EPA Taking This Action?

II. Air Quality and Health Impacts

A. Overview

B. Public Health Impacts

C. Environmental Impacts

D. Other Criteria Pollutants Affected by This Final Rule

E. Emissions from Locomotive and Marine Diesel Engines

III. Emission Standards

A. What Locomotives and Marine Engines Are Covered?

B. What Standards Are We Adopting?

C. Are the Standards Feasible?

IV. Certification and Compliance Program

A. Issues Common to Locomotives and Marine Engines

B. Compliance Issues Specific to Locomotives

C. Compliance Issues Specific to Marine Engines

V. Costs and Economic Impacts

A. Engineering Costs

B. Cost Effectiveness

C. EIA

VI. Benefits

VII. Alternative Program Options

A. Summary of Alternatives

B. Summary of Results

VIII. Public Participation

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132 (Federalism)

F. Executive Order 13175 (Consultation and Coordination With

Indian Tribal Governments)

G. Executive Order 13045: Protection of Children From

Environmental Health and Safety Risks

H. Executive Order 13211: Actions That Significantly Affect

Energy Supply, Distribution, or Use

I. National Technology Transfer Advancement Act

J. Executive Order 12898: Federal Actions to Address

Environmental Justice in Minority Populations and Low-Income

Populations

K. Congressional Review Act

X. Statutory Provisions and Legal Authority

I. Overview

This final rule completes an important step in EPA's ongoing

National Clean Diesel Campaign (NCDC) by adding new programs for

locomotives and marine diesel engines to the clean diesel initiatives

we have already undertaken for highway, other nonroad, and stationary

diesel engines. As detailed below, it significantly strengthens the

locomotive and marine diesel programs we proposed last year (72 FR

15938, April 3, 2007), especially in controlling emissions during the

critical early years through the early introduction of advanced

technologies and the more complete coverage of existing engines. When

fully implemented, this coordinated set of new programs will reduce

harmful diesel engine emissions to a small fraction of their previous

levels.

The new programs address all types of diesel locomotives-- line-

haul, switch, and passenger rail, and all types of marine diesel

engines below 30 liters per cylinder displacement (hereafter referred

to as ``marine diesel engines'').\2\ These engines are used to power a

wide variety of vessels, from small fishing and recreational boats to

large tugs and Great Lakes freighters. They are also used to generate

auxiliary vessel power, including on ocean-going ships.

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\2\ Marine diesel engines at or above 30 liters per cylinder,

called Category 3 engines, are typically used for propulsion power

on ocean-going ships. EPA is addressing Category 3 engines through

separate actions, including a planned rulemaking for a new tier of

federal standards (see Advance Notice of Proposed Rulemaking

published December 7, 2007 at 72 FR 69522) and participation on the

U.S. delegation to the International Maritime Organization for

negotiations of new international standards (see http://www.epa.gov/otaq/oceanvessels.com for information on both of those actions), as

well as EPA's Clean Ports USA Initiative (see http://www.epa.gov/cleandiesel/ports/index.htm).

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Emissions of fine particulate matter (PM2.5) and

nitrogen oxides (NOX) from these diesel engines contribute

to nonattainment of the National Ambient Air Quality Standards (NAAQS)

for PM2.5 and ozone. Today, locomotives and marine diesel

engines account for about 20 percent of mobile source NOX

emissions and 25 percent of mobile source diesel PM2.5

emissions in the U.S. Absent this final action, by 2030 the relative

contributions of NOX and PM2.5 from these engines

would have grown to 35 and 65 percent, respectively.

We are finalizing a comprehensive three-part program to address

this problem. First, we are adopting stringent emission standards for

existing locomotives and for existing commercial marine diesel engines

above 600 kilowatt (kW) (800 horsepower (hp)). These standards apply

when the engines are remanufactured. This part of the program will take

effect as soon as certified remanufacture systems are available, for

some engines as early as a few months from now. Under our existing

program, locomotives have been certified to one of three tiers of

standards: Tier 0 for locomotives originally built between 1973 and

2001, Tier 1 for those built between 2002 and 2004, and Tier 2 for

those built in or after 2005. Under this new program, certified

locomotive remanufacture systems must be made available by 2010 for

Tier 0 and Tier 1 locomotives, and by 2013 for Tier 2 locomotives.

Remanufacture systems that are certified for use in marine engine

remanufactures are likewise required to be used. We are not, however,

setting a specific compliance date for certified marine diesel

remanufacture systems because we expect that engine manufacturers will

be well motivated by the market opportunity to certify emissions-

compliant systems.

Second, we are adopting a set of near-term emission standards,

referred to as Tier 3, for newly-built locomotives and

[[Page 37098]]

marine engines. The Tier 3 standards reflect the application of

technologies to reduce engine-out particulate matter (PM) and

NOX.

Third, we are adopting longer-term standards, referred to as Tier

4, for newly-built locomotives and marine engines. Tier 4 standards

reflect the application of high-efficiency catalytic aftertreatment

technology enabled by the availability of ultra-low sulfur diesel fuel

(ULSD). These standards take effect in 2015 for locomotives, and phase

in over time for marine engines, beginning in 2014. Finally, we are

adopting provisions in all three parts of the program to eliminate

emissions from unnecessary locomotive idling.

Locomotives and marine diesel engines designed to these Tier 4

standards will achieve PM reductions of 90 percent and NOX

reductions of 80 percent, compared to engines meeting the current Tier

2 standards. The new standards will also yield sizeable reductions in

emissions of nonmethane hydrocarbons (NMHC), carbon monoxide (CO), and

hazardous compounds known as air toxics. Table I-1 summarizes the PM

and NOX emission reductions for the new standards compared

to today's (Tier 2) emission standards; for remanufactured engines, the

comparison is to the current standards for each tier of locomotives

covered, and to typical unregulated levels for marine engines.

Table I-1.--Reductions From Levels of Existing Standards

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PM

Sector Standards tier (percent) NOX (percent)

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Locomotives............................. Remanufactured Tier 0.......... 60 15-20.

Remanufactured Tier 1.......... 50 ........................

Remanufactured Tier 2.......... 50 ........................

Tier 3......................... 50 ........................

Tier 4......................... 90 80.

All tiers--idle emissions...... 50 50.

Marine Diesel Engines \a\............... Remanufactured Engines......... 25-60 Up to 20.

Tier 3......................... 50 20.

Tier 4......................... 90 80.

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Note: (a) Standards vary by displacement and within power categories. Reductions indicated are typical.

On a nationwide annual basis, these reductions will amount to

800,000 tons of NOX and 27,000 tons of PM by 2030, resulting

annually in the prevention of up to 1,100 PM-related premature deaths,

280 ozone-related premature deaths, 120,000 lost work days, 120,000

school day absences, and 1.1 million minor restricted-activity days. We

estimate the annual monetized health benefits of this rule in 2030 will

range from $9.2 billion to $11 billion, assuming a 3 percent discount

rate, or between $8.4 billion to $10 billion, assuming a 7% discount

rate.\3\ The estimated annual social cost of the program in 2030 is

projected to be $740 million, significantly less than the estimated

benefits.

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\3\ Low and high benefits estimates are derived from a range of

ozone-related premature mortality studies (including an assumption

of no causality) and PM2.5-related premature mortality

based on the ACS study (Pope et al., 2002). Benefits also include

PM2.5- and ozone-related morbidity benefits. See section

VI for a complete discussion and analysis of benefits associated

with the final rule.

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

This final rule makes a number of important changes to the program

set out in our Notice of Proposed Rulemaking (NPRM). Among these are

changes that will yield significantly greater overall NOX

and PM reductions, especially in the critical early years of the

program: The adoption of standards for remanufactured marine engines

and a 2-year pull-ahead of the Tier 4 NOX requirements for

line-haul locomotives and for 2000-3700 kW (2760-4900 hp) marine

engines.

The major elements of the final program are summarized below. We

are also revising existing testing, certification, and compliance

provisions to better ensure emissions control in use. Detailed

provisions and our justifications for them are discussed in sections

III and IV. Section VII of this preamble describes a number of

alternatives that we considered in developing the rule. After

evaluating the alternatives, we believe that our new program provides

the best opportunity for achieving timely and very substantial

emissions reductions from locomotive and marine diesel engines. It

balances a number of key factors: (1) Achieving very significant

emissions reductions as early as possible, (2) providing appropriate

lead time to develop and apply advanced control technologies, and (3)

coordinating requirements in this final rule with existing highway and

nonroad diesel engine programs. The provisions we are finalizing that

are different from the proposed program are:

The adoption of standards for remanufactured marine diesel

engines to address emissions from the existing fleet (this was

presented as one of the proposal alternatives),

Inclusion of Tier 4 NOX controls on 2015-2016

model year locomotives at initial build rather than at first

remanufacture,

A two-year pull-ahead of the Tier 4 NOX

standard for 2000-3700 kW marine engines to 2014,

Inclusion of Class II railroads in the remanufactured

locomotives program,

No Tier 4 standards for the small fleet of large

recreational vessels at this time,

A revised approach to migratory vessels that spend part of

their time overseas,

Credit for locomotive design measures that reduce

emissions as part of efforts to improve efficiency,

A number of changes to test and compliance requirements

detailed in sections III and IV.

Overall, our comprehensive three-part approach to setting standards

for locomotives and marine diesel engines will provide very large

reductions in PM, NOX, and toxic compounds, both in the

near-term (as early as 2008), and in the long-term. These reductions

will be achieved in a manner that: (1) Leverages technology

developments in other diesel sectors, (2) aligns well with the clean

diesel fuel requirements already being implemented, and (3) provides

the lead time needed to deal with the significant engineering design

workload that is involved.

(1) Locomotive Emission Standards

We are setting stringent exhaust emission standards for newly-built

and remanufactured locomotives, furthering

[[Page 37099]]

the initiative for cleaner locomotives started in 2004 with the

establishment of the ULSD locomotive fuel program, and adding this

important category of engines to the highway and nonroad diesel

applications already covered under EPA's National Clean Diesel

Campaign.

Briefly, for newly-built line-haul locomotives we are setting a new

Tier 3 PM standard of 0.10 grams per brake horsepower-hour (g/bhp-hr),

based on improvements to existing engine designs. This standard will

take effect in 2012. We are also setting new Tier 4 standards of 0.03

g/bhp-hr for PM and 1.3 g/bhp-hr for NOX, based on the

evolution of high-efficiency catalytic aftertreatment technologies now

being developed and introduced in the highway diesel sector. The Tier 4

standards will take effect in 2015. We are requiring that

remanufactured Tier 2 locomotives meet a PM standard of 0.10 g/bhp-hr,

based on the same engine design improvements as Tier 3 locomotives, and

that remanufactured Tier 0 and Tier 1 locomotives meet a 0.22 g/bhp-hr

PM standard. We are also requiring that remanufactured Tier 0

locomotives meet a NOX standard of 7.4 g/bhp-hr, the same

level as current Tier 1 locomotives, or 8.0 g/bhp-hr if the locomotive

is not equipped with a separate loop intake air cooling system. Section

III provides a detailed discussion of these new standards, and section

IV details improvements being made to the applicable test,

certification, and compliance programs.

In setting our original locomotive emission standards in 1998, the

historic pattern of transitioning older line-haul locomotives to road-

and yard-switcher service resulted in our making little distinction

between line-haul and switch locomotives. Because of the increase in

the size of new locomotives in recent years, that pattern cannot be

sustained by the railroad industry, as today's 4000+ hp (3000+ kW)

locomotives are poorly suited for switcher duty. Furthermore, although

there is still a fairly sizeable legacy fleet of older smaller line-

haul locomotives that could find their way into the switcher fleet,

essentially the only newly-built switchers put into service over the

last two decades have been of radically different design, employing one

to three smaller high-speed diesel engines designed for use in nonroad

applications. We are establishing new standards and special

certification provisions for newly-built and remanufactured switch

locomotives that take these factors into account.

Locomotives spend a substantial amount of time idling, during which

they emit harmful pollutants, consume fuel, create noise, and increase

maintenance costs. We are requiring that idle controls, such as

Automatic Engine Stop/Start Systems (AESS), be included on all newly-

built Tier 3 and Tier 4 locomotives. We also are requiring that they be

installed on all existing locomotives that are subject to the new

remanufactured engine standards, at the point of first remanufacture

under the standards, unless already equipped with idle controls.

Additional idle emissions control beyond AESS is encouraged in our

program by factoring it into the certification test program.

(2) Marine Engine Emission Standards

We are setting emissions standards for newly-built and

remanufactured marine diesel engines with displacements up to 30 liters

per cylinder (referred to as Category 1 and 2, or C1 and C2, engines).

Newly-built engines subject to the new standards include those used in

commercial, recreational, and auxiliary power applications, and those

below 37 kW (50 hp) that were previously regulated in our nonroad

diesel program.

The new marine diesel engine standards include stringent engine-

based Tier 3 standards for newly-built marine diesel engines that phase

in beginning in 2009. These are followed by aftertreatment-based Tier 4

standards for engines above 600 kW (800 hp) that phase in beginning in

2014. The specific levels and implementation dates for the Tier 3 and

Tier 4 standards vary by engine size and power. This yields an array of

emission standards levels and start dates that help ensure the most

stringent standards feasible at the earliest possible time for each

group of newly-built marine engines, while helping engine and vessel

manufacturers implement the program in a manner that minimizes their

costs for emission reductions. The new standards and implementation

schedules, as well as their technological feasibility, are described in

detail in section III of this preamble.

We are also adopting standards to address the considerable impact

of emissions from large marine diesel engines installed in vessels in

the existing fleet. These standards apply to commercial marine diesel

engines above 600 kW when these engines are remanufactured, and take

effect as soon as certified remanufacture systems are available. The

final requirements are different from the programmatic alternative on

which we sought comment in that there is no mandatory date by which

marine remanufacture systems must be made available. However, systems

for the larger Category 2 marine diesel engines are expected to become

available at the same time as the locomotive remanufacture systems for

similar engines, as early as 2008, because Category 2 marine diesel

engines are often derived from locomotive engines. This new marine

remanufacture program is described in more detail in section

III.B(2)(b). We intend to revisit this program in the future to

evaluate the extent to which remanufacture systems are being introduced

into the market without a mandatory requirement, and to determine if

the program should be extended to small commercial and recreational

engines as well.

Taken together, the program elements described above constitute a

comprehensive program that addresses the problems caused by locomotive

and marine diesel emissions from both a near-term and long-term

perspective. It does this while providing for an orderly and cost-

effective implementation schedule for the railroads, vessel owners,

manufacturers, and remanufacturers.

B. Why Is EPA Taking This Action?

(1) Locomotives and Marine Diesels Contribute to Serious Air Pollution

Problems

As we discuss extensively in both the proposal and today's action,

EPA strongly believes it is appropriate to take steps now to reduce

future emissions from locomotive and marine diesel engines. Emissions

from these engines generate significant emissions of PM2.5

and NOX that contribute to nonattainment of the National

Ambient Air Quality Standards for PM2.5 and ozone.

NOX is a key precursor to ozone and secondary PM formation.

These engines also emit hazardous air pollutants or air toxics, which

are associated with serious adverse health effects. Finally, emissions

from locomotive and marine diesel engines cause harm to public welfare,

including contributing to visibility impairment and other harmful

environmental impacts across the U.S.

The health and environmental effects associated with these

emissions are a classic example of a negative externality (an activity

that imposes uncompensated costs on others). With a negative

externality, an activity's social cost (the cost borne to society

imposed as a result of the activity taking place) exceeds its private

cost (the cost to those directly engaged in the activity). In this

case, as described below and in section

[[Page 37100]]

II, emissions from locomotives and marine diesel engines and vessels

impose public health and environmental costs on society. However, these

added costs are not reflected in the costs of those using these engines

and equipment. The current market and regulatory scheme do not correct

this externality because firms in the market are rewarded for

minimizing their production costs, including the costs of pollution

control, and do not benefit from reductions in emissions. In addition,

firms that may take steps to use equipment that reduces air pollution

may find themselves at a competitive disadvantage compared to firms

that do not. The emission standards that EPA is finalizing help address

this market failure and reduce the negative externality from these

emissions by providing a regulatory incentive for engine and locomotive

manufacturers to produce engines and locomotives that emit fewer

harmful pollutants and for railroads and vessel builders and owners to

use those cleaner engines.

Emissions from locomotive and marine diesel engines account for

substantial portions of the country's current ambient PM2.5

and NOX levels. We estimate that today these engines account

for about 20 percent of mobile source NOX emissions and

about 25 percent of mobile source diesel PM2.5 emissions.

Under this rulemaking, by 2030, NOX emissions from these

diesel engines will be reduced annually by 800,000 tons and

PM2.5 emissions by 27,000 tons, and these reductions will

grow beyond 2030 as fleet turnover to the cleanest engines continues.

EPA has already taken steps to bring emissions levels from highway

and nonroad diesel vehicles and engines to very low levels over the

next decade, while the per horsepower-hour emission levels for

locomotive and marine diesel engines remain at much higher levels--

comparable to the emissions for highway trucks in the early 1990s.

Both ozone and PM2.5 contribute to serious public health

problems, including premature mortality, aggravation of respiratory and

cardiovascular disease (as indicated by increased hospital admissions

and emergency room visits, school absences, loss work days, and

restricted activity days), changes in lung function and increased

respiratory symptoms, altered respiratory defense mechanisms, and

chronic bronchitis. Diesel exhaust is of special public health concern,

and since 2002 EPA has classified exposure to diesel exhaust as likely

to be carcinogenic to humans by inhalation from environmental

exposures.\4\ Recent studies are showing that populations living near

large diesel emission sources such as major roadways, rail yards, and

marine ports are likely to experience greater diesel exhaust exposure

levels than the overall U.S. population, putting them at greater health

risks.5, 6

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\4\ U.S. EPA (2002) Health Assessment Document for Diesel Engine

Exhaust. EPA/600/8-90/057F. Office of Research and Development,

Washington DC. This document is available electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.

\5\ Kinnee, E.J.; Touman, J.S.; Mason, R.; Thurman, J.; Beidler,

A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile

emissions to road segments for air toxics modeling in an urban area.

Transport. Res. Part D 9: 139-150.

\6\ State of California Air Resources Board. Roseville Rail Yard

Study. Stationary Source Division, October 14, 2004. This document

is available electronically at: http://www.arb.ca.gov/diesel/documents/rrstudy.htm and State of California Air Resources Board.

Diesel Particulate Matter Exposure Assessment Study for the Ports of

Los Angeles and Long Beach, April 2006. This document is available

electronically at: http://www.arb.ca.gov/regact/marine2005/portstudy0406.pdf.

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EPA recently conducted an initial screening-level analysis \7\ of

selected marine port areas and rail yards to better understand the

populations that are exposed to diesel particulate matter (DPM)

emissions from these facilities.8, 9 This screening-level

analysis focused on a representative selection of national marine ports

and rail yards.\10\ Of the 47 marine ports and 37 rail yards selected,

the results indicate that at least 13 million people, including a

disproportionate number of low-income households, African-Americans,

and Hispanics, living in the vicinity of these facilities, are being

exposed to ambient DPM levels that are 2.0 [mu]g/m3 and 0.2

[mu]g/m3 above levels found in areas further from these

facilities. Because those populations exposed to DPM emissions from

marine ports and rail yards are more likely to be low-income and

minority residents, these populations will benefit from the controls

being finalized in this action. The detailed findings of this study are

available in the public docket for this rulemaking.

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\7\ This type of screening-level analysis is an inexact tool and

not appropriate for regulatory decisionmaking; it is useful in

beginning to understand potential impacts and for illustrative

purposes. Additionally, the emissions inventories used as inputs for

the analyses are not official estimates and likely underestimate

overall emissions because they are not inclusive of all emission

sources at the individual ports in the sample. For example, most

inventories included emissions from ocean-going vessels (powered by

Category 3 engines), as well as some commercial vessel categories,

including harbor crafts, (powered by Category 1 and 2 engines),

cargo handling equipment, locomotives, and heavy-duty vehicles. This

final rule will not address emissions from ocean-going vessels,

cargo handling equipment or heavy-duty vehicles.

\8\ ICF International. September 28, 2007. Estimation of diesel

particulate matter concentration isopleths for marine harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\9\ ICF International. September 28, 2007. Estimation of diesel

particulate matter population exposure near selected harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\10\ The Agency selected a representative sample of the top 150

U.S. ports including coastal, inland, and Great Lake ports. In

selecting a sample of rail yards the Agency identified a subset from

the hundreds of rail yards operated by Class I Railroads.

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Today, millions of Americans continue to live in areas that do not

meet existing air quality standards. Currently, ozone concentrations

exceeding the 8-hour ozone NAAQS occur over wide geographic areas,

including most of the nation's major population centers. As of October

10, 2007, approximately 88 million people live in 39 designated areas

(which include all or part of 208 counties) that either do not meet the

current PM2.5 NAAQS or contribute to violations in other

counties, and 144 million people live in 81 areas (which include all or

part of 368 counties) designated as not in attainment for the 8-hour

ozone NAAQS. These numbers do not include the people living in areas

where there is a significant future risk of failing to maintain or

achieve either the current or future PM2.5 or ozone NAAQS.

In addition to public health impacts, there are public welfare and

environmental impacts associated with ozone and PM2.5

emissions. Ozone causes damage to vegetation which leads to crop and

forestry economic losses, as well as harm to national parks, wilderness

areas, and other natural systems. NOX and direct emissions

of PM2.5 can contribute to the impairment of visibility in

many parts of the U.S., where people live, work, and recreate,

including national parks, wilderness areas, and mandatory class I

federal areas. The deposition of airborne particles can also reduce the

aesthetic appeal of buildings and culturally important objects through

soiling and can contribute directly (or in conjunction with other

pollutants) to structural damage by means of corrosion or erosion.

Finally, NOX emissions from diesel engines contribute to the

acidification, nitrification, and eutrophication of water bodies.

While EPA has already adopted many emission control programs that

are expected to reduce ambient ozone and PM2.5 levels,

including the Clean Air Interstate Rule (CAIR) (70 FR 25162, May 12,

2005) and the Clean Air

[[Page 37101]]

Nonroad Diesel Rule (69 FR 38957, June 29, 2004), the Heavy Duty Engine

and Vehicle Standards and Highway Diesel Fuel Sulfur Control

Requirements (66 FR 5002, Jan. 18, 2001), and the Tier 2 Vehicle and

Gasoline Sulfur Program (65 FR 6698, Feb. 10, 2000), the additional

PM2.5 and NOX emission reductions resulting from

this rule will assist states in attaining and maintaining the Ozone and

the PM2.5 NAAQS both near term and in the decades to come.

In September 2006, EPA finalized revised PM2.5 NAAQS

standards and over the next few years the EPA will undergo the process

of designating areas that do not meet this new standard. EPA modeling,

conducted as part of finalizing the revised NAAQS, projects that in

2015 up to 52 counties with 53 million people may violate either the

daily or annual standards for PM2.5 (or both), while an

additional 27 million people in 54 counties may live in areas that have

air quality measurements within 10 percent of the revised NAAQS. Even

in 2020 up to 48 counties, with 54 million people, may still not be

able to meet the revised PM2.5 NAAQS and an additional 25

million people, living in 50 counties, are projected to have air

quality measurements within 10 percent of the revised standards. The

locomotive and marine diesel PM2.5 reductions resulting from

this rulemaking are needed by a number of states to both attain and

maintain the revised PM2.5 NAAQS.

State and local governments continue working to protect the health

of their citizens and comply with requirements of the Clean Air Act

(CAA or ``the Act''). As part of this effort they recognize the need to

secure additional major reductions in both diesel PM2.5 and

NOX emissions by undertaking numerous state-level

actions.11 However, they have also urged Agency action to

finalize a strong locomotive and marine diesel engine program that will

provide crucial emission reductions both in the near and long-term.

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\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.

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The federal program finalized today results in earlier and

significantly greater NOX and PM reductions from the

locomotive and marine sector than the proposed program because of the

first-ever national standards for remanufactured marine engines and the

starting of Tier 4 NOX requirements for line-haul

locomotives and for 2000-3700 kW (2760-4900 hp) marine engines two

years earlier than proposed. These changes reflect important

cooperative efforts by the regulated industry to implement cleaner

technology as early as possible. While the program finalized today will

help many states and communities achieve cleaner air, for some areas,

such as the South Coast of California, the reductions achieved through

this rule will not alone enable them to meet their near-term ozone and

PM air quality goals. This was also the case for our 1998 locomotive

rulemaking, where the State of California worked with Class I railroads

operating in southern California to develop a Memoranda of

Understanding (MOU) ensuring that the cleanest technologies enabled by

federal rules were expeditiously introduced in areas of California with

greatest air quality improvement needs. EPA continues to support

California's efforts to reconcile likely future growth in the

locomotive and marine sector with the public health protection needs of

the area, and today's final rule includes provisions which are well-

suited to encouraging early deployment of cleaner technologies through

the development of similar programs.

In addition to these new standards, EPA has a number of voluntary

programs that help enable government, industry, and local communities

to address challenging air quality problems. The EPA SmartWay program

has worked with railroads to encourage them to reduce unnecessary

locomotive idling and will continue to promote the use of innovative

idle reduction technologies that can substantially reduce locomotive

emissions while reducing fuel consumption. EPA's National Clean Diesel

Campaign, through its Clean Ports USA program is working with port

authorities, terminal operators, and trucking and rail companies to

promote cleaner diesel technologies and emission reduction strategies

through education, incentives, and financial assistance. Part of these

efforts involves voluntary retrofit programs that can further reduce

emissions from the existing fleet of diesel engines. Finally, EPA is

implementing a new Sustainable Ports Strategy which will allow EPA to

partner with ports, business partners, communities and other

stakeholders to become world leaders in sustainability, including

achieving cleaner air. This new strategy builds on the success of

collaborative work EPA has been doing in partnership with the American

Association of Port Authorities (AAPA), and through port related

efforts of Clean Ports USA, SmartWay, EPA's Regional Diesel

Collaboratives and other programs. Together these approaches augment

the regulations being finalized today, helping states and communities

achieve larger reductions sooner in the areas of our country that need

them the most.

(2) Advanced Technologies Can Be Applied

Air pollution from locomotive and marine diesel exhaust is a

challenging problem. However, we believe it can be addressed

effectively through a combination of engine-out emission reduction

technologies and high-efficiency catalytic aftertreatment technologies.

As discussed in greater detail in section III.C, the development of

these aftertreatment technologies for highway and nonroad diesel

applications has advanced rapidly in recent years, so that new engines

can achieve very large emission reductions in PM and NOX (in

excess of 90 and 80 percent, respectively).

High-efficiency PM control technologies are being broadly used in

many parts of the world and are being used domestically to comply with

EPA's heavy-duty truck standards that started taking effect in the 2007

model year. These technologies are highly durable and robust in use and

have proved extremely effective in reducing exhaust hydrocarbon (HC)

and carbon monoxide emissions.

Control of NOX emissions from locomotive and marine

diesel engines can also be achieved with high-efficiency exhaust

emission control technologies. Such technologies are expected to be

used to meet the stringent NOX standards included in EPA's

heavy-duty highway diesel and nonroad Tier 4 programs and have been in

production for heavy-duty trucks in Europe since 2005 and in many

stationary source applications throughout the world.

Section III.C discusses additional engineering challenges in

applying these technologies to newly-built locomotive and marine

engines, as well as the development steps that we expect to be taken to

resolve the challenges. With the lead time available and the assurance

of ULSD for the locomotive and marine sectors in 2012, as provided by

our 2004 final rule for nonroad engines and fuel, we are confident the

application of advanced technology to locomotives and marine diesel

engines will proceed at a reasonable rate of progress and will result

in systems

[[Page 37102]]

capable of achieving the new standards on time.

(3) Basis for Action Under the Clean Air Act

Authority for the actions promulgated in this document is granted

to the EPA by sections 114, 203, 205, 206, 207, 208, 213, 216, and

301(a) of the Clean Air Act as amended in 1990 (42 U.S.C. 7414, 7522,

7524, 7525, 7541, 7542, 7547, 7550 and 7601(a)).

Authority to Set Standards. EPA is promulgating emissions standards

for new marine diesel engines pursuant to its authority under section

213(a)(3) and (4) of the CAA. EPA is promulgating emission standards

for new locomotives and new engines used in locomotives pursuant to its

authority under section 213(a)(5) of the CAA.

EPA has previously determined that certain existing locomotive

engines, when they are remanufactured, are returned to as-new condition

and are expected to have the same performance, durability, and

reliability as freshly-manufactured locomotive engines. Consequently we

set emission standards for these remanufactured engines that apply at

the time of remanufacture (defined as ``to replace, or inspect and

qualify, each and every power assembly of a locomotive or locomotive

engine, whether during a single maintenance event or cumulatively

within a five-year period * * *'' (see 61 FR 53102, October 4, 1996; 40

CFR 92.2). In this action we are adopting new tiers of standards for

both freshly manufactured and remanufactured locomotives and locomotive

engines.

In the proposal for this rulemaking we also discussed applying a

similar approach to marine diesel engines. Many marine diesel engines,

particularly those above 600 kW (800 hp), periodically undergo a

maintenance process that returns them to as-new condition. A full

rebuild that brings an engine back to as-new condition includes a

complete overhaul of the engine, including piston, rings, liners,

turbocharger, heads, bearings, and geartrain/camshaft removal and

replacement. Engine manufacturers typically provide instructions for

such a full rebuild. Marine diesel engine owners complete this process

to maintain engine reliability, durability, and performance over the

life of their vessel, and to avoid the need to repower (replace the

engine) before their vessel wears out. A commercial marine vessel can

be in operation in excess of 40 years, which means that a marine diesel

engine may be remanufactured to as-new condition three or more times

before the vessel is scrapped.

Because these remanufactured engines are returned to as-new

condition, section 213(a)(3) and (4) give EPA the authority to set

emission standards for those engines. We are adopting requirements for

remanufactured marine diesel engines, described in section III.B(2)(b)

of this action. For the purpose of this program, we are defining

remanufacture as the replacement of all cylinder liners, either in one

maintenance event or over the course of five years (for the purpose of

this program, ``replacement'' includes the removing, inspecting and

requalifying a liner). While replacement of cylinder liners is only one

element of a full rebuild, it is common to all rebuilds. Marine diesel

engines that do not have their cylinder liners replaced all at once or

within a five-year period, or that do not perform cylinder liner

replacement at all, are not considered to be returned to as-new

condition and therefore are not considered to be remanufactured. Those

engines will not be subject to the marine remanufacture requirements.

Pollutants That Can Be Regulated. CAA section 213(a)(3) directs the

Administrator to set NOX, volatile organic compounds (VOCs),

or carbon monoxide standards for classes or categories of engines such

as marine diesel engines that contribute to ozone or carbon monoxide

concentrations in more than one nonattainment area. These ``standards

shall achieve the greatest degree of emission reduction achievable

through the application of technology which the Administrator

determines will be available for the engines or vehicles, giving

appropriate consideration to cost, lead time, noise, energy, and safety

factors associated with the application of such technology.''

CAA section 213(a)(4) authorizes the Administrator to establish

standards to control emissions of pollutants which ``may reasonably be

anticipated to endanger public health and welfare'' where the

Administrator determines, as it has done for emissions of PM, that

nonroad engines as a whole contribute significantly to such air

pollution. The Administrator may promulgate regulations that are deemed

appropriate, taking into account costs, noise, safety, and energy

factors, for classes or categories of new nonroad vehicles and engines

which cause or contribute to such air pollution.

Level of the Standards. CAA section 213(a)(5) directs EPA to adopt

emission standards for new locomotives and new engines used in

locomotives that achieve the ``greatest degree of emissions reductions

achievable through the use of technology that the Administrator

determines will be available for such vehicles and engines, taking into

account the cost of applying such technology within the available time

period, the noise, energy, and safety factors associated with the

applications of such technology.'' Section 213(a)(5) does not require

any review of the contribution of locomotive emissions to pollution,

though EPA does provide such information in this rulemaking. As

described in section III of this preamble and in chapter 4 of the final

Regulatory Impact Analysis (RIA), EPA has evaluated the available

information to determine the technology that will be available for

locomotives and engines subject to EPA standards.

Certification and Implementation. EPA is also acting under its

authority to implement and enforce both the marine diesel emission

standards and the locomotive emission standards. Section 213(d)

provides that the standards EPA adopts for both new locomotive and

marine diesel engines ``shall be subject to sections 206, 207, 208, and

209'' of the Clean Air Act, with such modifications that the

Administrator deems appropriate to the regulations implementing these

sections. In addition, the locomotive and marine standards ``shall be

enforced in the same manner as [motor vehicle] standards prescribed

under section 202'' of the Act. Section 213(d) also grants EPA

authority to promulgate or revise regulations as necessary to determine

compliance with, and enforce, standards adopted under section 213.

Technological Feasibility and Cost of Standards. The evidence

provided in section III.C of this Preamble and in chapter 4 of the RIA

indicates that the stringent emission standards we are setting today

for newly-built and remanufactured locomotive and marine diesel engines

are feasible and reflect the greatest degree of emission reduction

achievable through the use of technology that will be available in the

model years to which they apply. We have given appropriate

consideration to costs in setting these standards. Our review of the

costs and cost-effectiveness of these standards indicate that they will

be reasonable and comparable to the cost-effectiveness of other

emission reduction strategies that EPA has required in prior

rulemakings. We have also reviewed and given appropriate consideration

to the energy factors of this rule in terms of fuel efficiency as well

as any safety and noise factors associated with these standards.

Health and Environmental Need for the Standards. The information in

[[Page 37103]]

section II of this Preamble and chapter 2 of the RIA regarding air

quality and public health impacts provides strong evidence that

emissions from marine diesel engines and locomotives significantly and

adversely impact public health or welfare. EPA has already found in

previous rules that emissions from new marine diesel engines contribute

to ozone and carbon monoxide concentrations in more than one area which

has failed to attain the ozone and carbon monoxide NAAQS (64 FR 73300,

December 29, 1999). EPA has also previously determined that it is

appropriate to establish PM standards for marine diesel engines under

section 213(a)(4), and the additional information on the

carcinogenicity of exposure to diesel exhaust noted above reinforces

this finding. In addition, we have already found that emissions from

nonroad engines as a whole significantly contribute to air pollution

that may reasonably be anticipated to endanger public welfare due to

regional haze and visibility impairment (67 FR 68241, Nov. 8, 2002). We

find here, based on the information in the NPRM and in section II of

this preamble and Chapters 2 and 3 of the final RIA, that emissions

from the new marine diesel engines likewise contribute to regional haze

and to visibility impairment.

The PM and NOX emission reductions resulting from these

standards are important to states' efforts in attaining and maintaining

the ozone and the PM2.5 NAAQS in the near term and in the

decades to come. As noted above, the risk to human health and welfare

will be significantly reduced by the standards finalized in today's

action.

II. Air Quality and Health Impacts

The locomotive and marine diesel engines subject to this final rule

generate significant emissions of particulate matter (PM) and nitrogen

oxides (NOX) that contribute to nonattainment of the

National Ambient Air Quality Standards (NAAQS) for PM2.5 and

ozone. These engines also emit hazardous air pollutants or air toxics

that are associated with serious adverse health effects and contribute

to visibility impairment and other harmful environmental impacts across

the U.S.

By 2030, these standards are expected to reduce annual locomotive

and marine diesel engine PM2.5 emissions by 27,000 tons;

NOX emissions by 800,000 tons; and volatile organic compound

(VOC) emissions by 43,000 tons as well as reducing carbon monoxide (CO)

and toxic compounds known as air toxics.\12\

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\12\ Nationwide locomotive and marine diesel engines comprise

approximately 3 percent of the nonroad mobile sources hydrocarbon

inventory. EPA National Air Quality and Emissions Trends Report

1999. March 2001, Document Number: EPA 454/R-0-004. This document is

available in Docket EPA-HQ-OAR-2003-0190. This document is available

electronically at: http://www.epa.gov/air/airtrends/aqtrnd99/.

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We project that reductions of PM2.5, NOX, and

VOC emissions from locomotive and marine diesel engines will produce

nationwide air quality improvements. According to air quality modeling

performed in conjunction with this rule, all 39 current

PM2.5 nonattainment areas will experience a decrease in

their projected 2030 design values. Likewise the 133 mandatory class I

federal areas that EPA modeled will all see improvements in their

visibility. This rule will also result in nationwide ozone benefits. In

2030, 573 counties (of 579 that have monitored data) experience at

least a 0.1 ppb decrease in their ozone design values.

A. Overview

From a public health perspective, we are concerned with locomotive

and marine diesel engines' contributions to atmospheric levels of

particulate matter in general, diesel PM2.5 in particular,

various gaseous air toxics, and ozone. Today, locomotive and marine

diesel engine emissions represent a substantial portion of the U.S.

mobile source diesel PM2.5 and NOX inventories,

approximately 20 percent of mobile source NOX and 25 percent

of mobile source diesel PM2.5. Over time, the relative

contribution of these diesel engines to air quality problems is

expected to increase as the emission contribution from other mobile

sources decreases and the usage of locomotives and marine vessels

increases. By 2030, without the additional emissions controls finalized

in today's rule, locomotive and marine diesel engines will emit about

65 percent of the total mobile source diesel PM2.5 emissions

and 35 percent of the total mobile source NOX emissions.

Based on the most recent data available for this rule, air quality

problems continue to persist over a wide geographic area of the United

States. As of October 10, 2007 there are approximately 88 million

people living in 39 designated areas (which include all or part of 208

counties) that either do not meet the current PM2.5 NAAQS or

contribute to violations in other counties, and 144 million people

living in 81 areas (which include all or part of 366 counties)

designated as not in attainment for the 8-hour ozone NAAQS. These

numbers do not include the people living in areas where there is a

significant future risk of failing to maintain or achieve either the

current or future PM2.5 or ozone NAAQS. Figure II-1

illustrates the widespread nature of these problems. This figure

depicts counties which are currently designated nonattainment for

either or both the 8-hour ozone NAAQS and PM2.5 NAAQS. It

also shows the location of mandatory class I federal areas for

visibility.

BILLING CODE 1505-01-D

[[Page 37104]]

[GRAPHIC] [TIFF OMITTED] TR06MY08.000

BILLING CODE 1505-01-C

[[Page 37105]]

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.

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\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.

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Beyond the impact locomotive and marine diesel engines have on our

nation's ambient air quality the diesel exhaust emissions from these

engines are also of particular concern since exposure to diesel exhaust

is classified as likely to be carcinogenic to humans by inhalation from

environmental levels of exposure.\14\ Many people spend a large portion

of time in or near areas of concentrated locomotive or marine diesel

emissions, near rail yards, marine ports, railways, and waterways.

Recent studies show that populations living near large diesel emission

sources such as major roadways,\15\ rail yards \16\ and marine ports

\17\ are likely to experience greater diesel exhaust exposure levels

than the overall U.S. population, putting them at a greater health

risk.

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\14\ U.S. EPA (2002) Health Assessment Document for Diesel

Engine Exhaust. EPA/600/8-90/057F. Office of Research and

Development, Washington, DC. This document is available in Docket

EPA-HQ-OAR-2003-0190. This document is available electronically at

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.

\15\ Kinnee, E.J.; Touma, J.S.: Mason, R.; Thurman, J.; Beidler,

A.; Bailey, C.; Cook, R. (2004) Allocation of onroad mobile

emissions to road segments for air toxics modeling in an urban area.

Transport. Res. Part D 9:139-150; also see Cohen, J.; Cook, R;

Bailey, C.R.; Carr, E. (2005) Relationship between motor vehicle

emissions of hazardous pollutants, roadway proximity, and ambient

concentrations in Portland, Oregon. Environ. Modeling & Software 20:

7-12.

\16\ Hand, R.; Di, P; Servin, A.; Hunsaker, L.; Suer, C. (2004)

Roseville Rail Yard Study. California Air Resources Board. This

document is available in Docket EPA-HQ-OAR-2003-0190. [Online at

http://www.arb.ca.gov/diesel/documents/rrstudy.htm].

\17\ Di P.; Servin, A.; Rosenkranz, K.; Schwehr, B.; Tran, H.

(April 2006); Diesel Particulate Matter Exposure Assessment Study

for the Ports of Los Angeles and Long Beach. State of California Air

Resources Board.

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EPA recently conducted an initial screening-level analysis \18\ of

selected marine port areas and rail yards to better understand the

populations that are exposed to diesel particulate matter (DPM)

emissions from these facilities.19, 20 This screening-level

analysis focused on a representative selection of national marine ports

and rail yards.\21\ Of the 47 marine ports and 37 rail yards selected,

the results indicate that at least 13 million people, including a

disproportionate number of low-income households, African-Americans,

and Hispanics, living in the vicinity of these facilities, are being

exposed to ambient DPM levels that are 2.0 [mu]g/m3 and 0.2

[mu]g/m3 above levels found in areas further from these

facilities. Because those populations exposed to DPM emissions from

marine ports and rail yards are more likely to be low-income and

minority residents, these populations will benefit from the controls

being finalized in this action. The detailed findings of this study are

available in the public docket for this rulemaking.

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\18\ This type of screening-level analysis is an inexact tool

and not appropriate for regulatory decision-making; it is useful in

beginning to understand potential impacts and for illustrative

purposes. Additionally, the emissions inventories used as inputs for

the analyses are not official estimates and likely underestimate

overall emissions because they are not inclusive of all emission

sources at the individual ports in the sample. For example, most

inventories included emissions from ocean-going vessels (powered by

Category 3 engines), as well as some commercial vessel categories,

including harbor crafts (powered by Category 1 and 2 engines), cargo

handling equipment, locomotives, and heavy-duty vehicles. This final

rule will not address emissions from ocean-going vessels, cargo

handling equipment or heavy-duty vehicles.

\19\ ICF International. September 28, 2007. Estimation of diesel

particulate matter concentration isopleths for marine harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\20\ ICF International. September 28, 2007. Estimation of diesel

particulate matter population exposure near selected harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\21\ The Agency selected a representative sample of the top 150

U.S. ports including coastal, inland and Great Lake ports. In

selecting a sample of rail yards the Agency identified a subset from

the hundreds of rail yards operated by Class I Railroads.

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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.

[[Page 37106]]

(a) Background

Particulate matter (PM) represents a broad class of chemically and

physically diverse substances. It can be principally characterized as

discrete particles that exist in the condensed (liquid or solid) phase

spanning several orders of magnitude in size. PM is further described

by breaking it down into size fractions. PM10 refers to particles

generally less than or equal to 10 micrometers ([mu]m) in diameter.

PM2.5 refers to fine particles, generally less than or equal to 2.5

[mu]m in diameter. Inhalable (or ``thoracic'') coarse particles refer

to those particles generally greater than 2.5 [mu]m but less than or

equal to 10 [mu]m in diameter. Ultrafine PM refers to particles less

than 100 nanometers (0.1 [mu]m) in diameter. Larger particles tend to

be removed by the respiratory clearance mechanisms (e.g. coughing),

whereas smaller particles are deposited deeper in the lungs.

Fine particles are produced primarily by combustion processes and

by transformations of gaseous emissions (e.g., SOx, NOX and

VOC) in the atmosphere. The chemical and physical properties of PM2.5

may vary greatly with time, region, meteorology, and source category.

Thus, PM2.5 may include a complex mixture of different pollutants

including sulfates, nitrates, organic compounds, elemental carbon and

metal compounds. These particles can remain in the atmosphere for days

to weeks and travel hundreds to thousands of kilometers.

The primary PM2.5 NAAQS includes a short-term (24-hour)

and a long-term (annual) standard. The 1997 PM2.5 NAAQS

established by EPA set the 24-hour standard at a level of 65 [mu]g/

m3 based on the 98th percentile concentration averaged over

three years. The annual standard specifies an expected annual

arithmetic mean not to exceed 15 [mu]g/m3 averaged over

three years.

EPA has recently amended the NAAQS for PM2.5 (71 FR

61144, October 17, 2006). The final rule, signed on September 21, 2006,

addressed revisions to the primary and secondary NAAQS for PM to

provide increased protection of public health and welfare,

respectively. The level of the 24-hour PM2.5 NAAQS was

revised from 65 [mu]g/m3 to 35 [mu]g/m3 and the

level of the annual PM2.5 NAAQS was retained at 15 [mu]g/

m3. With regard to the secondary standards for

PM2.5, EPA has revised these standards to be identical in

all respects to the revised primary standards.

(b) Health Effects of PM2.5

Scientific studies show ambient PM is associated with a series of

adverse health effects. These health effects are discussed in detail in

the 2004 EPA Particulate Matter Air Quality Criteria Document (PM

AQCD), and the 2005 PM Staff Paper.22, 23 Further discussion

of health effects associated with PM can also be found in the RIA for

this rule.

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\22\ U.S. EPA (2004) Air Quality Criteria for Particulate Matter

(Oct 2004), Volume I Document No. EPA600/P-99/002aF and Volume II

Document No. EPA600/P-99/002bF. This document is available in Docket

EPA-HQ-OAR-2003-0190.

\23\ U.S. EPA (2005) Review of the National Ambient Air Quality

Standard for Particulate Matter: Policy Assessment of Scientific and

Technical Information, OAQPS Staff Paper. EPA-452/R-05-005. This

document is available in Docket EPA-HQ-OAR-2003-0190.

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Health effects associated with short-term exposures (hours to days)

to ambient PM include premature mortality, increased hospital

admissions, heart and lung diseases, increased cough, adverse lower-

respiratory symptoms, decrements in lung function and changes in heart

rate rhythm and other cardiac effects. Studies examining populations

exposed to different levels of air pollution over a number of years,

including the Harvard Six Cities Study and the American Cancer Society

Study, show associations between long-term exposure to ambient

PM2.5 and both total and cardiovascular and respiratory

mortality.\24\ In addition, a reanalysis of the American Cancer Society

Study shows an association between fine particle and sulfate

concentrations and lung cancer mortality.\25\

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\24\ Dockery, DW; Pope, CA III: Xu, X; et al. 1993. An

association between air pollution and mortality in six U.S. cities.

N Engl J Med 329:1753-1759.

\25\ Pope, C. A., III; Burnett, R. T.; Thun, M. J.; Calle, E.

E.; Krewski, D.; Ito, K.; Thurston, G. D. (2002) Lung cancer,

cardiopulmonary mortality, and long-term exposure to fine

particulate air pollution. J. Am. Med. Assoc. 287:1132-1141.

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The health effects of PM2.5 have been further documented

in local impact studies which have focused on health effects due to

PM2.5 exposures measured on or near roadways. These studies

take into account all air pollution sources, including both spark-

ignition (gasoline) and diesel powered vehicles, and indicate that

exposure to PM2.5 emissions near roadways, which are

dominated by mobile sources, are associated with potentially serious

health effects. For instance, a recent study found associations between

concentrations of cardiac risk factors in the blood of healthy young

police officers and PM2.5 concentrations measured in

vehicles.\26\ Also, a number of studies have shown associations between

residential or school outdoor concentrations of some fine particle

constituents that are found in motor vehicle exhaust, and adverse

respiratory outcomes, including asthma prevalence in children who live

near major roadways.27, 28, 29 Although the engines

considered in this rule differ from those in these studies with respect

to their applications and fuel qualities, these studies provide an

indication of the types of health effects that might be expected to be

associated with personal exposure to PM2.5 emissions from

large marine diesel and locomotive engines.

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\26\ Riediker, M.; Cascio, W.E.; Griggs, T.R.; et al. (2004)

Particulate matter exposure in cars is associated with

cardiovascular effects in healthy young men. Am J Respir Crit Care

Med 169: 934-940.

\27\ Van Vliet, P.; Knape, M.; de Hartog, J.; Janssen, N.;

Harssema, H.; Brunekreef, B. (1997). Motor vehicle exhaust and

chronic respiratory symptoms in children living near freeways. Env.

Research 74: 122-132.

\28\ Brunekreef, B., Janssen, N.A.H.; de Hartog, J.; Harssema,

H.; Knape, M.; van Vliet, P. (1997). Air pollution from truck

traffic and lung function in children living near roadways.

Epidemiology 8:298-303.

\29\ Kim, J.J.; Smorodinsky, S.; Lipsett, M.; Singer, B.C.;

Hodgson, A.T.; Ostro, B. (2004). Traffic-related air pollution near

busy roads: The East Bay children's respiratory health study. Am. J.

Respir. Crit. Care Med. 170: 520-526.

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Recent new studies from the State of California provide evidence

that PM2.5 emissions within marine ports and rail yards can

contribute significantly to elevated ambient concentrations near these

sources.30, 31 A substantial number of people experience

exposure to locomotive and marine diesel engine emissions, raising

potential health concerns. The controls finalized in this action will

help reduce exposure to PM2.5, specifically exposure to

marine port and rail yard related diesel PM2.5 sources.

Additional information on marine port and rail yard emissions and

ambient exposures can be found in Chapter 2 of the RIA.

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\30\ State of California Air Resources Board. Roseville Rail

Yard Study. Stationary Source Division, October 14, 2004. This

document is available in Docket EPA-HQ-OAR-2003-0190. This document

is available electronically at: http://www.arb.ca.gov/diesel/documents/rrstudy.htm.

\31\ State of California Air Resources Board. Diesel Particulate

Matter Exposure Assessment Study for the Ports of Los Angeles and

Long Beach, April 2006. This document is available in Docket EPA-HQ-

OAR-2003-0190. This document is available electronically at: ftp://ftp.arb.ca.gov/carbis/msprog/offroad/marinevess/documents/portstudy0406.pdf.

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(c) Current and Projected PM2.5 Levels

[[Page 37107]]

PM2.5 concentrations exceeding the level of the

PM2.5 NAAQS occur in many parts of the country.\32\ In 2005

EPA designated 39 nonattainment areas for the 1997 PM2.5

NAAQS (70 FR 943, January 5, 2005). These areas are comprised of 208

full or partial counties with a total population exceeding 88 million.

The 1997 PM2.5 NAAQS was recently revised and the 2006

PM2.5 NAAQS became effective on December 18, 2006. Table II-

1 presents the number of counties in areas currently designated as

nonattainment for the 1997 PM2.5 NAAQS as well as the number

of additional counties that have monitored data that is violating the

2006 PM2.5 NAAQS.

Table II-1.--Fine Particle Standards: Current Nonattainment Areas and

Other Violating Counties

------------------------------------------------------------------------

Nonattainment areas/other violating Number of

counties counties Population a

------------------------------------------------------------------------

1997 PM2.5 Standards: 39 areas currently 208 88,394,000

designated.............................

2006 PM2.5 Standards: counties with 49 18,198,676

violating monitors b...................

-------------------------------

Total............................... 257 106,595,676

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Notes:

(a) Population numbers are from 2000 census data.

(b) This table provides an estimate of the counties violating the 2006

PM2.5 NAAQS based on 2003-05 air quality data. The areas designated as

nonattainment for the 2006 PM2.5 NAAQS will be based on 3 years of air

quality data from later years. Also, the county numbers in the summary

table includes only the counties with monitors violating the 2006

PM2.5 NAAQS. The monitored county violations may be an underestimate

of the number of counties and populations that will eventually be

included in areas with multiple counties designated nonattainment.

A number of state governments have told EPA that they need the

reductions this rule will provide in order to meet and maintain the

PM2.5 NAAQS. Areas designated as not attaining the 1997

PM2.5 NAAQS will need to attain the 1997 standards in the

2010 to 2015 time frame, and then maintain them thereafter. The

attainment dates associated with the potential new 2006

PM2.5 nonattainment areas are likely to be in the 2015 to

2020 timeframe. The emission standards finalized in this action become

effective as early as 2008 making the NOX, PM, and VOC

inventory reductions from this rulemaking useful to states in attaining

or maintaining the PM2.5 NAAQS.

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\32\ A listing of the PM2.5 nonattainment areas is

included in the RIA for this rule.

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EPA has already adopted many emission control programs that are

expected to reduce ambient PM2.5 levels and which will

assist in reducing the number of areas that fail to achieve the

PM2.5 NAAQS. Even so, our air quality modeling for this

final rule projects that in 2020, with all current controls but

excluding the reductions achieved through this rule, up to 11 counties

with a population of 24 million may not attain the current annual

PM2.5 standard of 15 [mu]g/m3. These numbers do

not account for additional areas that have air quality measurements

within 10 percent of the annual PM2.5 standard. These areas,

although not violating the standards, will also benefit from the

additional reductions from this rule ensuring long-term maintenance of

the PM2.5 NAAQS.

Air quality modeling performed for this final rule shows that in

2020 and 2030 all 39 current PM2.5 nonattainment areas will

experience decreases in their PM2.5 design values. For areas

with current PM2.5 design values greater than 15 [mu]g/

m3 the modeled future-year population weighted

PM2.5 design values are expected to decrease on average by

0.08 [mu]g/m3 in 2020 and by 0.16 [mu]g/m3 in

2030. The maximum decrease for future-year PM2.5 design

values will be 0.38 [mu]g/m3 in 2020 and 0.81 [mu]g/

m3 in 2030. The air quality modeling methodology and the

projected reductions are discussed in more detail in Chapter 2 of the

RIA.

(2) Ozone

The locomotive and marine engine standards finalized in this action

are expected to result in significant reductions of NOX and

VOC emissions. NOX and VOC contribute to the formation of

ground-level ozone pollution or smog. People in many areas across the

U.S. continue to be exposed to unhealthy levels of ambient ozone.

(a) Background

Ground-level ozone pollution is typically formed by the reaction of

volatile organic compounds (VOC) and nitrogen oxides (NOX)

in the lower atmosphere in the presence of heat and sunlight. These

pollutants, often referred to as ozone precursors, are emitted by many

types of pollution sources, such as highway and nonroad motor vehicles

and engines, power plants, chemical plants, refineries, makers of

consumer and commercial products, industrial facilities, and smaller

area sources.

The science of ozone formation, transport, and accumulation is

complex.\33\ Ground-level ozone is produced and destroyed in a cyclical

set of chemical reactions, many of which are sensitive to temperature

and sunlight. When ambient temperatures and sunlight levels remain high

for several days and the air is relatively stagnant, ozone and its

precursors can build up and result in more ozone than typically occurs

on a single high-temperature day. Ozone can also be transported into an

area from pollution sources found hundreds of miles upwind, resulting

in elevated ozone levels even in areas with low local VOC or

NOX emissions.

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\33\ U.S. EPA Air Quality Criteria for Ozone and Related

Photochemical Oxidants (Final). U.S. Environmental Protection

Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document

is available in Docket EPA-HQ-OAR-2003-0190. This document may be

accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.

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The current ozone NAAQS, established by EPA in 1997, has an 8-hour

averaging time. The 8-hour ozone NAAQS is met at an ambient air quality

monitoring site when the average of the annual fourth-highest daily

maximum 8-hour average ozone concentration over three years is less

than or equal to 0.084 ppm. On June 20, 2007, EPA proposed to

strengthen the ozone NAAQS, the proposed revisions reflect new

scientific evidence about ozone and its effects on people and public

welfare.\34\ The final

[[Page 37108]]

ozone NAAQS rule is scheduled for March 2008.

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\34\ EPA proposed to set the 8-hour primary ozone standard to a

level within the range of 0.070-0.075 ppm. The agency also requested

comments on alternative levels of the 8-hour primary ozone standard,

within a range from 0.060 ppm up to and including retention of the

current standard (0.084 ppm). EPA also proposed two options for the

secondary ozone standard. One option would establish a new form of

standard designed specifically to protect sensitive plants from

damage caused by repeated ozone exposure throughout the growing

season. This cumulative standard would add daily ozone

concentrations across a three-month period. EPA proposed to set the

level of the cumulative standard within the range of 7 to 21 ppm-

hours. The other option would follow the current practice of making

the secondary standard equal to the proposed 8-hour primary

standard.

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(b) Health Effects of Ozone

The health and welfare effects of ozone are well documented and are

assessed in EPA's 2006 ozone Air Quality Criteria Document (ozone AQCD)

and EPA Staff Paper.35, 36 Ozone can irritate the

respiratory system, causing coughing, throat irritation, and/or

uncomfortable sensation in the chest. Ozone can reduce lung function

and make it more difficult to breathe deeply; breathing may also become

more rapid and shallow than normal, thereby limiting a person's

activity. Ozone can also aggravate asthma, leading to more asthma

attacks that require medical attention and/or the use of additional

medication. There is evidence of an elevated risk of mortality

associated with acute exposure to ozone, especially in the summer or

warm season when ozone levels are typically high. Animal toxicological

evidence indicates that with repeated exposure, ozone can inflame and

damage the lining of the lungs, which may lead to permanent changes in

lung tissue and irreversible reductions in lung function. People who

are more susceptible to effects associated with exposure to ozone can

include children, the elderly, and individuals with respiratory disease

such as asthma. Those with greater exposures to ozone, for instance due

to time spent outdoors (e.g., children and outdoor workers), are also

of particular concern.

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\35\ U.S. EPA Air Quality Criteria for Ozone and Related

Photochemical Oxidants (Final). U.S. Environmental Protection

Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document

is available in Docket EPA-HQ-OAR-2003-0190. This document may be

accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.

\36\ U.S. EPA (2007) Review of the National Ambient Air Quality

Standards for Ozone, Policy Assessment of Scientific and Technical

Information. OAQPS Staff Paper.EPA-452/R-07-003. This document is

available in Docket EPA-HQ-OAR-2003-0190. This document is available

electronically at: http:www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_.html.

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The recent ozone AQCD also examined relevant new scientific

information that has emerged in the past decade, including the impact

of ozone exposure on such health effects as changes in lung structure

and biochemistry, inflammation of the lungs, exacerbation and causation

of asthma, respiratory illness-related school absence, hospital

admissions and premature mortality. Animal toxicological studies have

suggested potential interactions between ozone and PM with increased

responses observed to mixtures of the two pollutants compared to either

ozone or PM alone. The respiratory morbidity observed in animal studies

along with the evidence from epidemiologic studies supports a causal

relationship between acute ambient ozone exposures and increased

respiratory-related emergency room visits and hospitalizations in the

warm season. In addition, there is suggestive evidence of a

contribution of ozone to cardiovascular-related morbidity and non-

accidental and cardiopulmonary mortality.

(c) Current and Projected Ozone Levels

Ozone concentrations exceeding the level of the 8-hour ozone NAAQS

occur over wide geographic areas, including most of the nation's major

population centers.\37\ As of October 10, 2007, there were

approximately 144 million people living in 81 areas (which include all

or part of 366 counties) designated as not in attainment with the 8-

hour ozone NAAQS. These numbers do not include the people living in

areas where there is a future risk of failing to maintain or attain the

8-hour ozone NAAQS.

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\37\ A listing of the 8-hour ozone nonattainment areas is

included in the RIA for this rule.

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States with 8-hour ozone nonattainment areas are required to take

action to bring those areas into compliance in the future. Based on the

final rule designating and classifying 8-hour ozone nonattainment areas

(69 FR 23951, April 30, 2004), most 8-hour ozone nonattainment areas

will be required to attain the ozone NAAQS in the 2007 to 2013 time

frame and then maintain the NAAQS thereafter.\38\ Many of these

nonattainment areas will need to adopt additional emission reduction

programs and the NOX and VOC reductions from this final

action are particularly important for these states. In addition, EPA's

review of the ozone NAAQS is currently underway with a final rule

scheduled for March 2008. If the ozone NAAQS is revised then new

nonattainment areas will be designated. While EPA is not relying on it

for purposes of justifying this rule, the emission reductions from this

rulemaking will also be helpful to states if EPA revises the ozone

NAAQS to be more stringent.

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\38\ The Los Angeles South Coast Air Basin 8-hour ozone

nonattainment area will have to attain before June 15, 2021.

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EPA has already adopted many emission control programs that are

expected to reduce ambient ozone levels. These control programs are

described in section I.B.1 of this preamble. As a result of these

programs, the number of areas that fail to meet the 8-hour ozone NAAQS

in the future is expected to decrease. Based on the air quality

modeling performed for this rule, which does not include any additional

local controls, we estimate nine counties (where 22 million people are

projected to live) will exceed the 8-hour ozone NAAQS in 2020.\39\ An

additional 39 counties (where 29 million people are projected to live)

are expected to be within 10 percent of violating the 8-hour ozone

NAAQS in 2020.

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\39\ We expect many of the 8-hour ozone nonattainment areas to

adopt additional emission reduction programs but we are unable to

quantify or rely upon future reductions from additional state and

local programs that have not yet been adopted.

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This rule results in reductions in nationwide ozone levels. The air

quality modeling projects that in 2030, 573 counties (of 579 that have

monitored data) experience at least a 0.1 ppb decrease in their ozone

design values. There are three nonattainment areas in southern

California, the Los Angeles-South Coast Air Basin nonattainment area,

the Riverside Co. (Coachella Valley) nonattainment area and the Los

Angeles--San Bernardino (W. Mojave) nonattainment area, which will

experience 8-hour ozone design value increases due to the

NOX disbenefits which occur in these VOC-limited ozone

nonattainment areas. Briefly, NOX reductions at certain

times and in some areas can lead to increased ozone levels. The air

quality modeling methodology (Section 2.3), the projected reductions

(Section 2.2.4), and the limited NOX disbenefits (Section

2.2.4.2.1), are discussed in more detail in Chapter 2 of the RIA.

Results from the air quality modeling conducted for this final rule

indicate that the locomotive and marine diesel engine emission

reductions in 2020 and 2030 will improve both the average and

population-weighted average ozone concentrations for the U.S. In

addition, the air quality modeling shows that on average this final

rule will help bring counties closer to ozone attainment as well as

assist counties whose ozone concentrations are within ten percent below

the standard. For example, in projected nonattainment counties, on a

population-weighted basis, the 8-hour ozone design value will on

average decrease by 0.13 ppb in 2020 and 0.62 ppb in 2030.\40\

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\40\ Ozone design values are reported in parts per million (ppm)

as specified in 40 CFR part 50. Due to the scale of the design value

changes in this action, results have been presented in parts per

billion (ppb) format.

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The impact of the reductions has also been analyzed with respect to

those areas that have the highest design

[[Page 37109]]

values, at or above 85 ppb, in 2020. We project there will be nine U.S.

counties with design values at or above 85 ppb in 2020. After

implementation of this rule, we project that one of these nine counties

will drop below 85 ppb. Further, two of the nine counties will be at

least 10 percent closer to a design value of less than 85 ppb, and on

average all nine counties will be about 18 percent closer to a design

value of less than 85 ppb.

(3) Air Toxics

People experience elevated risk of cancer and other noncancer

health effects from exposure to the class of pollutants known

collectively as ``air toxics''. Mobile sources are responsible for a

significant portion of this exposure. According to the National Air

Toxic Assessment (NATA) for 1999, mobile sources, including locomotive

and marine diesel marine engines, were responsible for 44 percent of

outdoor toxic emissions and almost 50 percent of the cancer risk among

the 133 pollutants quantitatively assessed in the 1999 NATA. Benzene is

the largest contributor to cancer risk of all the assessed pollutants

and mobile sources were responsible for about 68 percent of all benzene

emissions in 1999. Although the 1999 NATA did not quantify cancer risks

associated with exposure to diesel exhaust, EPA has concluded that

diesel exhaust ranks with other emissions that the national-scale

assessment suggests pose the greatest relative risk.

According to the 1999 NATA, nearly the entire U.S. population was

exposed to an average level of air toxics that has the potential for

adverse respiratory noncancer health effects. This potential was

indicated by a hazard index (HI) greater than 1.\41\ Mobile sources

were responsible for 74 percent of the potential noncancer hazard from

outdoor air toxics in 1999. About 91 percent of this potential

noncancer hazard was from acrolein; \42\ however, the confidence in the

RfC for acrolein is medium \43\ and confidence in NATA estimates of

population noncancer hazard from ambient exposure to this pollutant is

low.\44\ It is important to note that NATA estimates of noncancer

hazard do not include the adverse health effects associated with

particulate matter identified in EPA's Particulate Matter Air Quality

Criteria Document. Gasoline and diesel engine emissions contribute

significantly to particulate matter concentration.

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\41\ To express chronic noncancer hazards, we used the RfC as

part of a calculation called the hazard quotient (HQ), which is the

ratio between the concentration to which a person is exposed and the

RfC. (RfC is defined by EPA as, ``an estimate of a continuous

inhalation exposure to the human population, including sensitive

subgroups, with uncertainty spanning perhaps an order of magnitude,

which is likely to be without appreciable risks of deleterious

noncancer effects during a lifetime.'') A value of the HQ less than

one indicates that the exposure is lower than the RfC and that no

adverse health effects would be expected. Combined noncancer hazards

were calculated using the hazard index (HI), defined as the sum of

hazard quotients for individual air toxic compounds that affect the

same target organ or system. As with the hazard quotient, a value of

the HI at or below 1.0 will likely not result in adverse effects

over a lifetime of exposure. However, a value of the HI greater than

1.0 does not necessarily suggest a likelihood of adverse effects.

Furthermore, the HI cannot be translated into a probability that

adverse effects will occur and is not likely to be proportional to

risk.

\42\ U.S. EPA (2006) National-Scale Air Toxics Assessment for

1999. This material is available electronically at http://www.epa.gov/ttn/atw/nata1999/risksum.html.

\43\ U.S. EPA (2003) Integrated Risk Information System File of

Acrolein. National Center for Environmental Assessment, Office of

Research and Development, Washington, D.C. 2003. This material is

available electronically at http://www.epa.gov/iris/subst/0364.htm.

\44\ U.S. EPA (2006) National-Scale Air Toxics Assessment for

1999. This material is available electronically at http://www.epa.gov/ttn/atw/nata1999/risksum.html.

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The NATA modeling framework has a number of limitations which

prevent its use as the sole basis for setting regulatory standards.

These limitations and uncertainties are discussed on the 1999 NATA

website.\45\ Even so, this modeling framework is very useful in

identifying air toxic pollutants and sources of greatest concern,

setting regulatory priorities, and informing the decision making

process.

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\45\ U.S. EPA (2006) National-Scale Air Toxics Assessment for

1999. http://www.epa.gov/ttn/atw/nata1999.

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The following section provides a brief overview of air toxics which

are associated with nonroad engines, including locomotive and marine

diesel engines, and provides a discussion of the health risks

associated with each air toxic.

(a) Diesel Exhaust (DE)

Locomotive and marine diesel engines emit diesel exhaust (DE), a

complex mixture comprised of carbon dioxide, oxygen, nitrogen, water

vapor, carbon monoxide, nitrogen compounds, sulfur compounds and

numerous low-molecular-weight hydrocarbons. A number of these gaseous

hydrocarbon components are individually known to be toxic, including

aldehydes, benzene and 1,3-butadiene. The diesel particulate matter

(DPM) present in diesel exhaust consists of fine particles (http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060. This document can be found in Docket

EPA-HQ-OAR-2003-0190.

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After being emitted in the engine exhaust, diesel exhaust undergoes

dilution as well as chemical and physical changes in the atmosphere.

The lifetime for some of the compounds present in diesel exhaust ranges

from hours to days.

(i) Diesel Exhaust: Potential Cancer Effects

In EPA's 2002 Diesel Health Assessment Document (Diesel HAD),\47\

exposure to diesel exhaust was classified as likely to be carcinogenic

to humans by inhalation from environmental exposures, in accordance

with the revised draft 1996/1999 EPA cancer guidelines. A number of

other agencies (National Institute for Occupational Safety and Health,

the International Agency for Research on Cancer, the World Health

Organization, California EPA, and the U.S. Department of Health and

Human Services) have made similar classifications. However, EPA also

concluded in the Diesel HAD that it is not possible currently to

calculate a cancer unit risk for diesel exhaust due to a variety of

factors that limit the current studies, such as limited quantitative

exposure histories in occupational groups investigated for lung cancer.

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\47\ U.S. EPA (2002) Health Assessment Document for Diesel

Engine Exhaust. EPA/600/8-90/057F Office of Research and

Development, Washington, DC. This document is available

electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060. This document can be found in Docket

EPA-HQ-OAR-2003-0190.

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For the Diesel HAD, EPA reviewed 22 epidemiologic studies on the

subject of the carcinogenicity of workers exposed

[[Page 37110]]

to diesel exhaust in various occupations, finding increased lung cancer

risk, although not always statistically significant, in 8 out of 10

cohort studies and 10 out of 12 case-control studies within several

industries, including railroad workers. Relative risk for lung cancer

associated with exposure ranged from 1.2 to 1.5, although a few studies

show relative risks as high as 2.6. Additionally, the Diesel HAD also

relied on two independent meta-analyses, which examined 23 and 30

occupational studies respectively, which found statistically

significant increases in smoking-adjusted relative lung cancer risk

associated with exposure to diesel exhaust, of 1.33 to 1.47. These

meta-analyses demonstrate the effect of pooling many studies and in

this case show the positive relationship between diesel exhaust

exposure and lung cancer across a variety of diesel exhaust-exposed

occupations.48, 49

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\48\ Bhatia, R., Lopipero, P., Smith, A. (1998) Diesel exposure

and lung cancer. Epidemiology 9(1):84-91.

\49\ Lipsett, M; Campleman, S; (1999) Occupational exposure to

diesel exhaust and lung cancer: a meta-analysis. Am J Public Health

80(7): 1009-1017.

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In the absence of a cancer unit risk, the Diesel HAD sought to

provide additional insight into the significance of the diesel exhaust-

cancer hazard by estimating possible ranges of risk that might be

present in the population. An exploratory analysis was used to

characterize a possible risk range by comparing a typical environmental

exposure level for highway diesel sources to a selected range of

occupational exposure levels. The occupationally observed risks were

then proportionally scaled according to the exposure ratios to obtain

an estimate of the possible environmental risk. A number of

calculations are needed to accomplish this, and these can be seen in

the EPA Diesel HAD. The outcome was that environmental risks from

diesel exhaust exposure could range from a low of 10-4 to

10-5 to as high as 10-3, reflecting the range of

occupational exposures that could be associated with the relative and

absolute risk levels observed in the occupational studies. Because of

uncertainties, the analysis acknowledged that the risks could be lower

than 10-4 or 10-5, and a zero risk from diesel

exhaust exposure was not ruled out.

Retrospective health studies of railroad workers have played an

important part in determining that exposure to diesel exhaust is likely

to be carcinogenic to humans by inhalation from environmental

exposures. Key evidence of the diesel exhaust exposure linkage to lung

cancer comes from two retrospective case-control studies of railroad

workers which are discussed at length in the Diesel HAD and summarized

in Chapter 2 of the RIA.

(ii) Diesel Exhaust: Other Health Effects

Noncancer health effects of acute and chronic exposure to diesel

exhaust emissions are also of concern to the EPA. EPA derived a diesel

exhaust reference concentration (RfC) from consideration of four well-

conducted chronic rat inhalation studies showing adverse pulmonary

effects.50, 51, 52, 53 The RfC is 5 [mu]g/

m3 for diesel exhaust as measured by diesel PM. This RfC

does not consider allergenic effects such as those associated with

asthma or immunologic effects. There is growing evidence, discussed in

the Diesel HAD, that exposure to diesel exhaust can exacerbate these

effects, but the exposure-response data are presently lacking to derive

an RfC. The EPA Diesel HAD states, ``With DPM [diesel particulate

matter] being a ubiquitous component of ambient PM, there is an

uncertainty about the adequacy of the existing DE [diesel exhaust]

noncancer database to identify all of the pertinent DE-caused noncancer

health hazards.'' (p. 9-19). The Diesel HAD concludes ``that acute

exposure to DE [diesel exhaust] has been associated with irritation of

the eye, nose, and throat, respiratory symptoms (cough and phlegm), and

neurophysiological symptoms such as headache, lightheadedness, nausea,

vomiting, and numbness or tingling of the extremities.'' \54\

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\50\ Ishinishi, N; Kuwabara, N; Takaki, Y; et al. (1988) Long-

term inhalation experiments on diesel exhaust. In: Diesel exhaust

and health risks. Results of the HERP studies. Ibaraki, Japan:

Research Committee for HERP Studies; pp. 11-84.

\51\ Heinrich, U; Fuhst, R; Rittinghausen, S; et al. (1995)

Chronic inhalation exposure of Wistar rats and two different strains

of mice to diesel engine exhaust, carbon black, and titanium

dioxide. Inhal. Toxicol. 7:553-556.

\52\ Mauderly, JL; Jones, RK; Griffith, WC; et al. (1987) Diesel

exhaust is a pulmonary carcinogen in rats exposed chronically by

inhalation. Fundam. Appl. Toxicol. 9:208-221.

\53\ Nikula, KJ; Snipes, MB; Barr, EB; et al. (1995) Comparative

pulmonary toxicities and carcinogenicities of chronically inhaled

diesel exhaust and carbon black in F344 rats. Fundam. Appl. Toxicol.

25:80-94.

\54\ ``Health Assessment Document for Diesel Engine Exhaust,''

U.S. Environmental Protection Agency, 600/8-90/057F, http://www.epa.gov/ttn/atw/dieselfinal.pdf, May 2002, p. 9-9.

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Exposure to diesel exhaust has also been shown to cause serious

noncancer effects in occupational exposure studies. One study of

railroad workers and electricians, cited in the Diesel HAD,\55\ found

that exposure to diesel exhaust resulted in neurobehavioral impairments

in one or more areas including reaction time, balance, blink reflex

latency, verbal recall, and color vision confusion indices. Pulmonary

function tests also showed that 10 of the 16 workers had airway

obstruction and another group of 10 of 16 workers had chronic

bronchitis, chest pain, tightness, and hyperactive airways. Finally, a

variety of studies have been published subsequent to the completion of

the Diesel HAD. One such study, published in 2006,\56\ found that

railroad engineers and conductors with diesel exhaust exposure from

operating trains had an increased incidence of chronic obstructive

pulmonary disease (COPD) mortality. The odds of COPD mortality

increased with years on the job so that those who had worked more than

16 years as an engineer or conductor after 1959 had an increased risk

of 1.61 (95% confidence interval, 1.12-2.30). EPA is assessing the

significance of this study within the context of the broader

literature.

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\55\ Kilburn (2000) See HAD Chapter 5-7.

\56\ Hart, JE; Laden F; Schenker, M.B.; and Garshick, E. Chronic

Obstructive Pulmonary Disease Mortality in Diesel-Exposed Railroad

Workers; Environmental Health Perspective July 2006: 1013-1016.

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(iii) Ambient PM2.5 Levels and Exposure to Diesel Exhaust PM

The Diesel HAD also briefly summarizes health effects associated

with ambient PM and discusses the EPA's annual PM2.5 NAAQS

of 15 [mu]g/m\3\. There is a much more extensive body of human data

showing a wide spectrum of adverse health effects associated with

exposure to ambient PM, of which diesel exhaust is an important

component. The PM2.5 NAAQS is designed to provide protection from the

noncancer and premature mortality effects of PM2.5 as a whole.

(iv) Diesel Exhaust PM Exposures

Exposure of people to diesel exhaust depends on their various

activities, the time spent in those activities, the locations where

these activities occur, and the levels of diesel exhaust pollutants in

those locations. The major difference between ambient levels of diesel

particulate and exposure levels for diesel particulate is that exposure

accounts for a person moving from location to location, proximity to

the emission source, and whether the exposure occurs in an enclosed

environment.

Occupational Exposures

Occupational exposures to diesel exhaust from mobile sources,

including

[[Page 37111]]

locomotive engines and marine diesel engines, can be several orders of

magnitude greater than typical exposures in the non-occupationally

exposed population.

Over the years, diesel particulate exposures have been measured for

a number of occupational groups. A wide range of exposures have been

reported, from 2 [mu]g/m3 to 1,280 [mu]g/m3, for

a variety of occupations. Studies have shown that miners and railroad

workers typically have higher diesel exposure levels than other

occupational groups studied, including firefighters, truck dock

workers, and truck drivers (both short and long haul).\57\ As discussed

in the Diesel HAD, the National Institute of Occupational Safety and

Health (NIOSH) has estimated a total of 1,400,000 workers are

occupationally exposed to diesel exhaust from on-road and nonroad

vehicles including locomotive and marine diesel engines.

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\57\ Diesel HAD Page 2-110, 8-12; Woskie, SR; Smith, TJ;

Hammond, SK: et al. (1988a) Estimation of the DE exposures of

railroad workers: II. National and historical exposures. Am J Ind

Med 12:381-394.

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Elevated Concentrations and Ambient Exposures in Mobile Source-Impacted

Areas

Regions immediately downwind of rail yards and marine ports may

experience elevated ambient concentrations of directly-emitted

PM2.5 from diesel engines. Due to the unique nature of rail

yards and marine ports, emissions from a large number of diesel engines

are concentrated in a small area. Furthermore, emissions occur at or

near ground level, allowing emissions of diesel engines to reach nearby

receptors without fully mixing with background air.

A 2004 study conducted by the California Air Resources Board (CARB)

examined the air quality impacts of railroad operations at the J.R.

Davis Rail Yard, the largest service and maintenance rail facility in

the western United States.\58\ The yard occupies 950 acres along a one-

quarter mile wide and four-mile long section of land in Roseville, CA.

The study developed an emissions inventory for the facility for the

year 2000 and modeled ambient concentrations of diesel PM using a well-

accepted dispersion model (ISCST3). The study estimated substantially

elevated diesel PM concentrations in an area 5,000 meters from the

facility, with higher concentrations closer to the rail yard. Using

local meteorological data, annual average contributions from the rail

yard to ambient diesel PM concentrations under prevailing wind

conditions were 1.74, 1.18, 0.80, and 0.25 [mu]g/m3 at

receptors located 200, 500, 1000, and 5000 meters from the yard,

respectively. Several tens of thousands of people live within the area

estimated to experience substantial increases in annual average ambient

PM2.5 as a result of these rail yard emissions.

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\58\ Hand, R.; Pingkuan, D.; Servin, A.; Hunsaker, L.; Suer, C.

(2004) Roseville rail yard study. California Air Resources Board.

[Online at http://www.arb.ca.gov/diesel/documents/rrstudy.htm] This

document can be found in Docket EPA-HQ-OAR-2003-0190.

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Another study from CARB evaluated air quality impacts of diesel

engine emissions within the Ports of Long Beach and Los Angeles in

California, one of the largest ports in the U.S.\59\ Like the earlier

rail yard study, the port study employed the ISCST3 dispersion model.

Using local meteorological data, annual average concentrations were

substantially elevated over an area exceeding 200,000 acres. Because

the ports are located near heavily-populated areas, the modeling

indicated that over 700,000 people lived in areas with at least 0.3

[mu]g/m\3\ of port-related diesel PM in ambient air, about 360,000

people lived in areas with at least 0.6 [mu]g/m3 of diesel

PM, and about 50,000 people lived in areas with at least 1.5 ug/

m3 of ambient diesel PM directly from the port. Most

recently, CARB released several additional Railyard Health Risk

Assessments which all show that diesel PM emissions result in

significantly higher pollution risks in nearby communities.\60\

Together these studies highlight the substantial contribution these

facilities make to elevated ambient concentrations in populated areas.

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\59\ State of California Air Resources Board. Diesel Particulate

Matter Exposure Assessment Study for the Ports of Los Angeles and

Long Beach, April 2006. This document is available in Docket EPA-HQ-

OAR-2003-0190. This document is available electronically at: ftp://ftp.arb.ca.gov/carbis/msprog/offroad/marinevess/documents/portstudy0406.pdf.

\60\ These studies are available in Docket EPA-HQ-OAR-2003-0190.

Studies are also available at http://www.arb.ca.gov/railyard/hra/hra.htm.

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As mentioned in section II.A of this preamble, EPA recently

conducted an initial screening-level analysis of a representative

selection of national marine port areas and rail yards to begin to

better understand the populations that are exposed to DPM emissions

from these facilities.61, 62 As part of this study, a

computer geographic information system (GIS) was used to identify the

locations and property boundaries of 47 marine ports and 37 rail yard

facilities.\63\ Census information was used to estimate the size and

demographic characteristics of the population living in the vicinity of

the ports and rail yards. The results indicate that at least 13 million

people, including a disproportionate number of low-income, African-

Americans, and Hispanics, live in the vicinity of these facilities and

are being exposed to ambient DPM levels that are 2.0 [mu]g/

m3 and 0.2 [mu]g/m3 above levels found in areas

further from these facilities. These populations will benefit from the

controls being finalized in this action. This study is discussed in

greater detail in chapter 2 of the RIA and detailed findings of this

study are available in the public docket for this rulemaking.

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\61\ ICF International. September 28, 2007. Estimation of diesel

particulate matter concentration isopleths for marine harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\62\ ICF International. September 28, 2007. Estimation of diesel

particulate matter population exposure near selected harbor areas

and rail yards. Memorandum to EPA under Work Assignment Number 0-3,

Contract Number EP-C-06-094. This memo is available in Docket EPA-

HQ-OAR-2003-0190.

\63\ The Agency selected a representative sample of the top 150

U.S. ports including coastal, inland, and Great Lake ports. In

selecting a sample of rail yards the Agency identified a subset from

the hundreds of rail yards operated by Class I Railroads.

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(b) Other Air Toxics--benzene, 1,3-butadiene, formaldehyde,

acetaldehyde, acrolein, POM, naphthalene

Locomotive and marine diesel engine exhaust emissions also

contribute to ambient levels of other air toxics known or suspected as

human or animal carcinogens, or that have noncancer health effects.

These other air toxics include benzene, 1,3-butadiene, formaldehyde,

acetaldehyde, acrolein, polycyclic organic matter (POM), and

naphthalene. All of these compounds, except acetaldehyde, were

identified as national or regional cancer risk or noncancer hazard

drivers in the 1999 National-Scale Air Toxics Assessment (NATA) and

have significant inventory contributions from mobile sources. That is,

for a significant portion of the population, these compounds pose a

significant portion of the total cancer and noncancer risk from

breathing outdoor air toxics. The reductions in locomotive and marine

diesel engine emissions finalized in this rulemaking will help reduce

exposure to these harmful substances.

Benzene: EPA has characterized benzene as a known human carcinogen

(causing leukemia) by all routes of exposure, and concludes that

exposure is associated with additional health effects, including

genetic changes in both humans and animals and increased proliferation

of bone marrow cells in

[[Page 37112]]

mice.64, 65, 66 EPA states in its IRIS database that data

indicate a causal relationship between benzene exposure and acute

lymphocytic leukemia and suggests a relationship between benzene

exposure and chronic non-lymphocytic leukemia and chronic lymphocytic

leukemia. The IARC has determined that benzene is a human carcinogen

and the U.S. DHHS has characterized benzene as a known human

carcinogen.67, 68

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\64\ U.S. EPA. 2000. Integrated Risk Information System File for

Benzene. This material is available electronically at http://www.epa.gov/iris/subst/0276.htm.

\65\ International Agency for Research on Cancer (IARC). 1982.

Monographs on the evaluation of carcinogenic risk of chemicals to

humans, Volume 29, Some industrial chemicals and dyestuffs, World

Health Organization, Lyon, France, p. 345-389.

\66\ Irons, R.D.; Stillman, W.S.; Colagiovanni, D.B.; Henry,

V.A. 1992. Synergistic action of the benzene metabolite hydroquinone

on myelopoietic stimulating activity of granulocyte/macrophage

colony-stimulating factor in vitro, Proc. Natl. Acad. Sci. 89:3691-

3695.

\67\ International Agency for Research on Cancer (IARC). 1987.

Monographs on the evaluation of carcinogenic risk of chemicals to

humans, Volume 29, Supplement 7, Some industrial chemicals and

dyestuffs, World Health Organization, Lyon, France.

\68\ U.S. Department of Health and Human Services National

Toxicology Program 11th Report on Carcinogens available at: http://ntp.niehs.nih.gov/go/16183.

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A number of adverse noncancer health effects including blood

disorders, such as preleukemia and aplastic anemia, have also been

associated with long-term exposure to benzene.69, 70 The

most sensitive noncancer effect observed in humans, based on current

data, is the depression of the absolute lymphocyte count in

blood.71, 72 In addition, recent work, including studies

sponsored by the Health Effects Institute (HEI), provides evidence that

biochemical responses are occurring at lower levels of benzene exposure

than previously known.73, 74, 75, 76 EPA's IRIS program has

not yet evaluated these new data.

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\69\ Aksoy, M. (1989). Hematotoxicity and carcinogenicity of

benzene. Environ. Health Perspect. 82: 193-197.

\70\ Goldstein, B.D. (1988). Benzene toxicity. Occupational

medicine. State of the Art Reviews. 3: 541-554.

\71\ Rothman, N., G.L. Li, M. Dosemeci, W.E. Bechtold, G.E.

Marti, Y.Z. Wang, M. Linet, L.Q. Xi, W. Lu, M.T. Smith, N. Titenko-

Holland, L.P. Zhang, W. Blot, S.N. Yin, and R.B. Hayes (1996)

Hematotoxicity among Chinese workers heavily exposed to benzene. Am.

J. Ind. Med. 29: 236-246.

\72\ U.S. EPA (2002) Toxicological Review of Benzene (Noncancer

Effects). Environmental Protection Agency, Integrated Risk

Information System (IRIS), Research and Development, National Center

for Environmental Assessment, Washington DC. This material is

available electronically at http://www.epa.gov/iris/subst/0276.htm.

\73\ Qu, O.; Shore, R.; Li, G.; Jin, X.; Chen, C.L.; Cohen, B.;

Melikian, A.; Eastmond, D.; Rappaport, S.; Li, H.; Rupa, D.;

Suramaya, R.; Songnian, W.; Huifant, Y.; Meng, M.; Winnik, M.; Kwok,

E.; Li, Y.; Mu, R.; Xu, B.; Zhang, X.; Li, K. (2003) HEI Report 115,

Validation & Evaluation of Biomarkers in Workers Exposed to Benzene

in China.

\74\ Qu, Q., R. Shore, G. Li, X. Jin, L.C. Chen, B. Cohen, et

al. (2002) Hematological changes among Chinese workers with a broad

range of benzene exposures. Am. J. Industr. Med. 42: 275-285.

\75\ Lan, Qing, Zhang, L., Li, G., Vermeulen, R., et al. (2004)

Hematotoxically in Workers Exposed to Low Levels of Benzene. Science

306: 1774-1776.

\76\ Turtletaub, K.W. and Mani, C. (2003) Benzene metabolism in

rodents at doses relevant to human exposure from Urban Air. Research

Reports Health Effect Inst. Report No.113.

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1,3-Butadiene: EPA has characterized 1,3-butadiene as carcinogenic

to humans by inhalation.77, 78 The IARC has determined that

1, 3-butadiene is a human carcinogen and the U.S. DHHS has

characterized 1,3-butadiene as a known human

carcinogen.79, 80 There are numerous studies consistently

demonstrating that 1,3-butadiene is metabolized into genotoxic

metabolites by experimental animals and humans. The specific mechanisms

of 1,3-butadiene-induced carcinogenesis are unknown; however, the

scientific evidence strongly suggests that the carcinogenic effects are

mediated by genotoxic metabolites. Animal data suggest that females may

be more sensitive than males for cancer effects associated with 1,3-

butadiene exposure; while there are insufficient data in humans from

which to draw conclusions about sensitive subpopulations.

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\77\ U.S. EPA (2002) Health Assessment of 1,3-Butadiene. Office

of Research and Development, National Center for Environmental

Assessment, Washington Office, Washington, DC. Report No. EPA600-P-

98-001F. This document is available electronically at http://www.epa.gov/iris/supdocs/buta-sup.pdf.

\78\ U.S. EPA (2002) Full IRIS Summary for 1,3-butadiene (CASRN

106-99-0). Environmental Protection Agency, Integrated Risk

Information System (IRIS), Research and Development, National Center

for Environmental Assessment, Washington, DC http://www.epa.gov/iris/subst/0139.htm.

\79\ International Agency for Research on Cancer (IARC) (1999)

Monographs on the evaluation of carcinogenic risk of chemicals to

humans, Volume 71, Re-evaluation of some organic chemicals,

hydrazine and hydrogen peroxide and Volume 97 (in preparation),

World Health Organization, Lyon, France.

\80\ U.S. Department of Health and Human Services (2005)

National Toxicology Program 11th Report on Carcinogens available at:

ntp.niehs.nih.gov/index.cfm?objectid=32BA9724-F1F6-975E-7FCE50709CB4C932.

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1,3-Butadiene also causes a variety of reproductive and

developmental effects in mice; no human data on these effects are

available. The most sensitive effect was ovarian atrophy observed in a

lifetime bioassay of female mice.\81\

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\81\ Bevan, C.; Stadler, J.C.; Elliot, G.S.; et al. (1996)

Subchronic toxicity of 4-vinylcyclohexene in rats and mice by

inhalation. Fundam. Appl. Toxicol. 32:1-10.

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Formaldehyde: Since 1987, EPA has classified formaldehyde as a

probable human carcinogen based on evidence in humans and in rats,

mice, hamsters, and monkeys.\82\ EPA is currently reviewing recently

published epidemiological data. For instance, research conducted by the

National Cancer Institute (NCI) found an increased risk of

nasopharyngeal cancer and lymphohematopoietic malignancies such as

leukemia among workers exposed to formaldehyde.83, 84 NCI is

currently updating these studies. A recent National Institute of

Occupational Safety and Health (NIOSH) study of garment workers also

found increased risk of death due to leukemia among workers exposed to

formaldehyde.\85\ Extended follow-up of a cohort of British chemical

workers did not find evidence of an increase in nasopharyngeal or

lymphohematopoietic cancers, but a continuing statistically significant

excess in lung cancers was reported.\86\ Recently, the IARC re-

classified formaldehyde as a human carcinogen (Group 1).\87\

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\82\ U.S. EPA (1987) Assessment of Health Risks to Garment

Workers and Certain Home Residents from Exposure to Formaldehyde,

Office of Pesticides and Toxic Substances, April 1987.

\83\ Hauptmann, M.; Lubin, J.H.; Stewart, P.A.; Hayes, R.B.;

Blair, A. 2003. Mortality from lymphohematopoetic malignancies among

workers in formaldehyde industries. Journal of the National Cancer

Institute 95: 1615-1623.

\84\ Hauptmann, M.; Lubin, J.H.; Stewart, P.A.; Hayes, R.B.;

Blair, A. 2004. Mortality from solid cancers among workers in

formaldehyde industries. American Journal of Epidemiology 159: 1117-

1130.

\85\ Pinkerton, L.E. 2004. Mortality among a cohort of garment

workers exposed to formaldehyde: an update. Occup. Environ. Med. 61:

193-200.

\86\ Coggon, D, EC Harris, J Poole, KT Palmer. 2003. Extended

follow-up of a cohort of British chemical workers exposed to

formaldehyde. J National Cancer Inst. 95:1608-1615.

\87\ International Agency for Research on Cancer (IARC). 2006.

Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. Volume

88. (in preparation), World Health Organization, Lyon, France.

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Formaldehyde exposure also causes a range of noncancer health

effects, including irritation of the eyes (burning and watering of the

eyes), nose and throat. Decreased pulmonary function has been observed

in humans. Effects from repeated exposure in humans include respiratory

tract irritation, chronic bronchitis and nasal epithelial lesions.\88\

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\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

[[Page 37113]]

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

[[Page 37114]]

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

[[Page 37115]]

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

[[Page 37116]]

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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(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

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Locomotive and Marine......................... 795,000 27,000

Clean Air Nonroad Diesel...................... 738,000 129,000

Heavy-Duty Highway............................ 2,600,000 109,000

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(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

This 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

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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

This text is long and has been trimmed here. Open the source document for the complete record.