[Federal Register Volume 72, Number 235 (Friday, December 7, 2007)]
[Proposed Rules]
[Pages 69522-69552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-23556]



[[Page 69521]]

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Part IV





Environmental Protection Agency





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40 CFR Parts 9 and 94



Control of Emissions From New Marine Compression-Ignition Engines at or 
Above 30 Liters per Cylinder; Proposed Rule

  Federal Register / Vol. 72, No. 235 / Friday, December 7, 2007 / 
Proposed Rules  

[[Page 69522]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9 and 94

[EPA-HQ-OAR-2007-0121; FRL-8502-5]
RIN 2060-AO38


Control of Emissions From New Marine Compression-Ignition Engines 
at or Above 30 Liters per Cylinder

AGENCY: Environmental Protection Agency (EPA).

ACTION: Advance notice of proposed rulemaking.

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SUMMARY: EPA is issuing this Advance Notice of Proposed Rulemaking 
(ANPRM) to invite comment from all interested parties on our plan to 
propose new emission standards and other related provisions for new 
compression-ignition marine engines with per cylinder displacement at 
or above 30 liters per cylinder. We refer to these engines as Category 
3 marine engines. We are considering standards for achieving large 
reductions in oxides of nitrogen (NOX) and particulate 
matter (PM) through the use of technologies such as in-cylinder 
controls, aftertreatment, and low sulfur fuel, starting as early as 
2011.
    Category 3 marine engines are important contributors to our 
nation's air pollution today and these engines are projected to 
continue generating large amounts of NOX, PM, and sulfur 
oxides (SOX) that contribute to nonattainment of the 
National Ambient Air Quality Standards (NAAQS) for PM2.5 and 
ozone across the United States. Ozone and PM2.5 are 
associated with serious public health problems including premature 
mortality, aggravation of respiratory and cardiovascular disease, 
aggravation of existing asthma, acute respiratory symptoms, chronic 
bronchitis, and decreased lung function. Category 3 marine engines are 
of concern as a source of diesel exhaust, which has been classified by 
EPA as a likely human carcinogen. A program such as the one under 
consideration would significantly reduce the contribution of Category 3 
marine engines to national inventories of NOX, PM, and 
SOX, as well as air toxics, and would reduce public exposure 
to those pollutants.

DATES: Comments must be received on or before March 6, 2008.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2007-0121, by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for 
submitting comments.
     E-mail: [email protected]
     Fax: (202) 566-9744
     Mail: Environmental Protection Agency, Mail Code: 6102T, 
1200 Pennsylvania Ave., NW., Washington, DC, 20460. Please include two 
copies.
     Hand Delivery: EPA Docket Center (Air Docket), U.S. 
Environmental Protection Agency, EPA West Building, 1301 Constitution 
Avenue, NW., Room: 3334 Mail Code: 2822T, Washington, DC. Such 
deliveries are only accepted during the Docket's normal hours of 
operation, and special arrangements should be made for deliveries of 
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2007-0121. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or e-mail. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through www.regulations.gov 
your e-mail address will be automatically captured and included as part 
of the comment that is placed in the public docket and made available 
on the Internet. If you submit an electronic comment, EPA recommends 
that you include your name and other contact information in the body of 
your comment and with any disk or CD-ROM you submit. If EPA cannot read 
your comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket visit the EPA Docket Center 
homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. 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, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the EPA Docket Center, EPA/
DC, EPA West, Room 3334, 1301 Constitution Avenue, 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: Michael Samulski, Assessment and 
Standards Division, Office of Transportation and Air Quality, 2000 
Traverwood Drive, Ann Arbor, MI, 48105; telephone number: (734) 214-
4532; fax number: (734) 214-4050; e-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does This Action Apply to Me?

    This action will affect companies that manufacture, sell, or import 
into the United States new marine compression-ignition engines for use 
on vessels flagged or registered in the United States; companies and 
persons that make vessels that will be flagged or registered in the 
United States and that use such engines; and the owners or operators of 
such U.S. vessels. Owners and operators of vessels flagged elsewhere 
may also be affected, to the extent they use U.S. shipyards or 
maintenance and repair facilities; see also Section VII.E regarding 
potential application of the standards to foreign vessels that enter 
U.S. ports. Finally, this action may also affect companies and persons 
that rebuild or maintain these engines. Affected categories and 
entities include the following:

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                                                                                Examples of potentially affected
               Category                             NAICS code \a\                          entities
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Industry..............................  333618................................  Manufacturers of new marine
                                                                                 diesel engines.
Industry..............................  336611................................  Manufacturers of marine vessels.
Industry..............................  811310................................  Engine repair and maintenance.

[[Page 69523]]

 
Industry..............................  483...................................  Water transportation, freight
                                                                                 and passenger.
Industry..............................  324110................................  Petroleum Refineries.
Industry..............................  422710, 422720........................  Petroleum Bulk Stations and
                                                                                 Terminals; Petroleum and
                                                                                 Petroleum Products Wholesalers.
 
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\a\ North American Industry Classification System (NAICS).

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

B. What Should I Consider as I Prepare My Comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
www.regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as 
CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives, 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified.

II. Additional Information About This Rulemaking

    The current emission standards for new compression-ignition marine 
engines with per cylinder displacement at or above 30 liters per 
cylinder were adopted in 2003 (see 68 FR 9746, February 28, 2003). This 
ANPRM relies in part on information that was obtained for that rule, 
which can be found in Public Docket EPA-HQ-OAR-2003-0045. This docket 
is incorporated into the docket for this action, EPA-HQ-OAR-2007-0121.

Table of Contents

I. Overview
    A. Background: EPA's Current Category 3 Standards
    B. Program Under Consideration
II. Why Is EPA Considering New Controls?
    A. Ozone and PM Attainment
    B. Public Health Impacts
    1. Particulate Matter
    2. Ozone
    3. Air Toxics
    C. Other Environmental Effects
    1. Visibility
    2. Plant and Ecosystem Effects of Ozone
    3. Acid Deposition
    4. Eutrophication and Nitrification
    5. Materials Damage and Soiling
III. Relevant Clean Air Act Provisions
IV. International Regulation of Air Pollution From Ships
V. Potential Standards and Effective Dates
    A. NOX Standards
    B. PM and SOX Standards
VI. Emission Control Technology
    A. Engine-Based NOX Control
    1. Traditional In-Cylinder Controls
    2. Water-Based Technologies
    3. Exhaust Gas Recirculation
    B. NOX Aftertreatment
    C. PM and SOX Control
    1. In-Cylinder Controls
    2. Fuel Quality
    3. Exhaust Gas Scrubbers
VII. Certification and Compliance
    A. Testing
    1. PM Sampling
    2. Low Power Operation
    3. Test Fuel
    B. On-off Technologies
    C. Parameter Adjustment
    D. Certification of Existing Engines
    E. Other Compliance Issues
    1. Engines on Foreign-Flagged Vessels
    2. Non-Diesel Engines
VIII. Potential Regulatory Impacts
    A. Emission Inventory
    1. Estimated Inventory Contribution
    2. Inventory Calculation Methodology
    B. Potential Costs
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

I. Overview

    In recent years, EPA has adopted major new programs designed to 
reduce emissions from diesel engines. When fully phased in, these new 
programs for highway \1\ and land-based nonroad \2\ diesel engines will 
lead to the elimination of over 90 percent of harmful regulated 
pollutants from these sources. The public health and welfare benefits 
of these actions are very significant, projected at over $70 billion 
and $83 billion for our highway and land-based nonroad diesel programs, 
respectively. In contrast, the corresponding cost of these programs 
will be a small fraction of this amount. We have estimated the annual 
cost at $4.2 billion and $2 billion, respectively in 2030. These 
programs are being implemented over the next decade.
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    \1\ 66 FR 5001, January 18, 2001.
    \2\ 69 FR 38957, June 29, 2004.
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    We have also recently proposed a new emission control program for 
locomotives and marine diesel engines.\3\ The proposed standards would 
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 (including propulsion engines used on vessels 
from recreational and small fishing boats to super-yachts, tugs and 
Great Lakes freighters, and auxiliary engines ranging from small 
generator sets to large generators on ocean-going

[[Page 69524]]

vessels).\4\ The proposal consists of a three-part program. First, we 
are proposing more stringent standards for existing locomotives that 
would apply when they are remanufactured; we are also requesting 
comment on a program that would apply a similar requirement to existing 
marine diesel engines up to 30 liters per cylinder displacement when 
they are remanufactured. Second, we are proposing a set of near-term 
emission standards, referred to as Tier 3, for newly-built locomotives 
and marine engines up to 30 liters per cylinder displacement that 
reflect the application of in-cylinder technologies to reduce engine-
out NOX and PM. Third, we are proposing longer-term 
standards for locomotive engines and certain marine diesel engines, 
referred to as Tier 4 standards, that reflect the application of high-
efficiency catalytic aftertreatment technology enabled by the 
availability of ultra-low sulfur diesel (ULSD) fuel.
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    \3\ 72 FR 15937, April 3, 2007.
    \4\ Marine diesel engines at or above 30 l/cyl displacement are 
not included in this program.
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    Marine diesel engines above 30 liters per cylinder, called Category 
3 marine diesel engines, are significant contributors to our national 
mobile source emission inventory. Category 3 marine engines are 
predominantly used in ocean-going vessels (OGV). The contribution of 
these engines to national inventories is described in section VIII.A of 
this preamble. These inventories are expected to grow significantly due 
to expected increases in foreign trade. Without new controls, we 
anticipate that their overall contribution to mobile source oxides of 
nitrogen (NOX) and fine diesel particulate matter 
(PM2.5) emissions will increase to about 34 and 45 percent 
respectively by 2030. Their contribution to emissions in port areas on 
a percentage basis would be expected to be significantly higher.
    Reducing emissions from these engines can lead to improvements in 
public health and would help states and localities attain and maintain 
the PM and ozone national ambient air quality standards. Both ozone and 
PM2.5 are associated with 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, lost work days, and 
restricted activity days), changes in lung function and increased 
respiratory symptoms, altered respiratory defense mechanisms, and 
chronic bronchitis. In addition, diesel exhaust is of special public 
health concern. Since 2002 EPA has classified diesel exhaust as likely 
to be carcinogenic to humans by inhalation at environmental 
exposures.\5\ Recent studies are showing that populations living near 
large diesel emission sources such as major roadways,\6\ rail yards, 
and marine ports \7\ are likely to experience greater diesel exhaust 
exposure levels than the overall U.S. population, putting them at 
greater health risks. We are currently studying the size of the U.S. 
population living near a sample of approximately 50 marine ports and 
will place this information in the docket for this ANPRM upon 
completion.
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    \5\ 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 is 
available in Docket EPA-HQ-OAR-2007-0121.
    \6\ 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.
    \7\ 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. This document is available in Docket EPA-HQ-OAR-
2007-0121.
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    Category 3 marine engines are currently subject to emission 
standards that rely on engine-based technologies to reduce emissions. 
These standards, which were adopted in 2003 and went into effect in 
2004, are equivalent to the NOX limits in Annex VI to the 
MARPOL Convention, adopted by a Conference of the Parties to the 
Convention in 1997. The opportunity to gain large additional public 
health benefits through the application of advanced emission control 
technologies, including aftertreatment, lead us to consider more 
stringent standards for these engines. In order to achieve these 
emission reductions on the ship, however, it may be necessary to 
control the sulfur content of the fuel used in these engines. Finally, 
because of the international nature of ocean-going marine 
transportation, and the very large inventory contribution from foreign-
flagged vessels, we may also consider the applicability of federal 
standards to foreign vessels that enter U.S. ports (see Section VII.E).
    In this ANPRM, we describe the emission program we are considering 
for Category 3 marine diesel engines and technologies we believe can be 
used to achieve those standards. The remainder of this section provides 
background on our current emission control program and gives an 
overview of the program we are considering. Section II provides a brief 
discussion of the health and human impacts of emissions from Category 3 
marine diesel engines. Section III identifies relevant Clean Air Act 
provisions and Section IV summarizes our interactions with the 
International Maritime Organization (IMO). In Sections V and VI, we 
describe the potential emission limits and the emission control 
technologies that can be used to meet them. Section VII discusses 
several compliance issues. In Section VIII, we summarize the 
contribution of these engines to current mobile source NOX 
and PM inventories in the United States and describe our plans for our 
future cost analysis. Finally, Section IX contains information on 
statutory and executive order reviews covering this action. We are 
interested in comments covering all aspects of this ANPRM.

A. Background: EPA's Current Category 3 Standards

    EPA currently has emission standards for Category 3 marine diesel 
engines. The standards, adopted in 2003, are equivalent to the MARPOL 
Annex VI NOX limits. They apply to any Category 3 engine 
installed on a vessel flagged or registered in the United States, 
beginning in 2004.
    In our 2003 final rule, we considered adopting standards that would 
achieve greater emission reductions through expanding the use and 
optimization of in-cylinder controls as well as through the use of 
advanced emission control technologies including water technologies 
(water injection, emulsification, humidification) and selective 
catalytic reduction (SCR). However, we determined that it was 
appropriate to defer a final decision on the longer-term Tier 2 
standards to a future rulemaking. While there was a certain amount of 
information available at the time about the advanced technologies, 
there were several outstanding technical issues concerning the 
widespread commercial use of those technologies. Deferring the Tier 2 
standards to a second rulemaking allowed us the opportunity to obtain 
important additional information on the use of these advanced 
technologies that we expected to become available over the next few 
years. This new information was expected to include: (1) New 
developments as manufacturers continue to make various improvements to 
the technology and address any remaining concerns, (2) data or 
experience from recently initiated in-use installations using the 
advanced technologies, and (3) information from

[[Page 69525]]

longer-term in-use experience with the advanced technologies that would 
be helpful for evaluating the long-term durability of emission 
controls. An additional reason to defer the adoption of long-term 
standards for Category 3 engines was to allow the United States to 
pursue further negotiations in the international arena to achieve more 
stringent global emission standards for marine diesel engines.\8\
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    \8\ 68 FR 9748, February 28, 2003.
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    Finally, because the standards adopted in our 2003 rulemaking were 
equivalent to the international standards, we determined that it was 
appropriate to defer a decision on the application of federal standards 
to engines on foreign-flagged vessels that enter U.S. ports. We 
indicated that we would consider this issue again in our future 
rulemaking, and we intend to evaluate how best to address emissions 
from foreign vessels in this action. We expect our proposal to reflect 
an approach similar to the emission program recently proposed by the 
United States in the current discussions at the IMO to amend the MARPOL 
Annex VI standards to a level that achieves significant reductions in 
NOX, PM, and SOX emissions from Category 3 marine 
diesel engines.\9\ We will evaluate progress at the IMO and, as 
appropriate, consider the application of new EPA national standards to 
engines on foreign-flagged vessels that enter U.S. ports under our 
Clean Air Act authority.
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    \9\ ``Revision of the MARPOL Annex VI, the NOX 
Technical Code and Related Guidelines; Development of Standards for 
NOX, PM, and SOX,'' submitted by the United 
States, BLG 11/5, Sub-Committee on Bulk Liquids and Gases, 11th 
Session, Agenda Item 5, February 9, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0034. This document is also available on our Web site: http://www.epa.gov/otaq/oceanvessels.com.
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B. Program Under Consideration

    As described in Section VI, continuing advancements in diesel 
engine control technology support the adoption of long-term technology-
forcing standards for Category 3 engines. With regard to NOX 
control, SCR has been applied to many land-based applications, and the 
technology continues to be refined and improved. More propulsion 
engines have been fitted with the technology, especially on vessels 
operating in the Baltic Sea, and it is being found to be very effective 
and durable in-use. These improvements, in addition to better 
optimization of engine-based controls, have the potential for 
significant NOX reductions. PM and SOX emissions 
from Category 3 engines are primarily due to the sulfur content of the 
fuel they use. In the short term, these emissions can be decreased by 
using fuel with a reduced sulfur content or through the use of exhaust 
gas cleaning technology; this is the idea behind the SOX 
Emission Control Areas (SECAs) provided for in Annex VI. More 
significant reductions can be obtained by using distillate fuel, and at 
least one company has been voluntarily switching from residual fuel to 
distillate fuel while their ships are operating within 24 nautical 
miles of certain California ports.\10\ Their experience demonstrates 
that this type of fuel switching can be done safely and efficiently, 
although the higher price of distillate fuel may limit this approach to 
near-coast and port areas. In addition, emission scrubbing techniques 
are improving, which have the potential for significant PM reductions 
from Category 3 engines.
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    \10\ See ``Maersk Line Announces Fuel Switch for Vessels Calling 
California'' at http://www.maerskline.com/globalfile/?path=/pdf/environment_fuel_initiative.
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    We are currently considering an emission control program for new 
Category 3 marine diesel engines that takes advantage of these new 
emission reduction approaches. The program we are considering, 
described in more detail in Section V, would focus on NOX, 
PM, and SOX control from new and existing engines. This 
program is similar to the one recently proposed at the IMO by the U.S. 
government.
    For NOX control for new engines, we are considering a 
two-phase approach. In the first phase, called Tier 2, we are 
considering a NOX emission limit for new engines that would 
be 15 to 25 percent below the current NOX limits as defined 
by the NOX curve in the current Tier 1 standards. These 
standards would apply at all times. In the second phase, called Tier 3, 
we are considering a NOX emission limit that would achieve 
an additional 80 percent reduction from the Tier 2 limits. We are 
considering the Tier 2 limits as early as 2011 and Tier 3 limits in the 
2016 time frame. Because Tier 3 standards are likely to be achieved 
using aftertreatment technologies, the application of the standards 
could be geographically-based thereby allowing operators to turn the 
system off while they are outside of a specified geographic area. That 
area could be the same as the compliance area for PM and SOX 
reductions (see below). This two-part approach would permit near-term 
emission reductions while achieving deeper reductions through long-term 
standards.
    We believe a two-phase approach under consideration is an effective 
way to maximize NOX emission reductions from these engines. 
While we continue to believe that the focus of the emission control 
program should be on meaningful long-term standards that would apply 
high-efficiency catalytic aftertreatment to these engines, short-term 
emission reductions could be achieved through incremental improvements 
to existing engine designs. These design improvements can be consistent 
with a long-term, after treatment-based Tier 3 program. The recent 
experience of engine manufacturers in applying advanced control 
technologies to other mobile sources suggests that incremental changes 
of the type that would be used to achieve the Tier 2 standards may also 
be used in strategies to achieve the Tier 3 standards. For example, 
Tier 2 technologies may allow engine manufacturers to size their 
aftertreatment control systems smaller. A more stringent Tier 2 control 
program, however, may risk diverting resources away from Tier 3 and may 
result in the application of emission reduction strategies that are not 
consistent with high-efficiency catalytic aftertreatment-based 
controls.
    For PM and SOX control, we are considering a performance 
standard that would reflect the use of low-sulfur distillate fuels or 
the use of exhaust gas cleaning technology (e.g., scrubbers), or a 
combination of both. These standards would apply as early as 2011 and 
would potentially achieve SOX reductions as high as 95 
percent and substantial PM reductions as well. We believe a performance 
standard would be a cost-effective approach for PM emission reductions 
since it allows ship owners to choose from a variety of mechanisms to 
achieve the standard, including fuel switching or the use of emission 
scrubbers. Compliance with the PM and SOX emissions could be 
limited to operation in a defined geographical area. For example, ships 
operating in the defined coastal areas (i.e., within a specified 
distance from shore) would be required to meet the requirements while 
operating within the area, but could ``turn off'' the control mechanism 
while on the open sea. This type of performance standard could apply to 
all vessels, new or existing, that operate within the designated area. 
An important advantage of a geographic approach for PM and 
SOX control, as well as the Tier 3 standards, is that it 
would result in emission reductions that are important for health and 
human welfare while reducing the costs of the program since ships will 
not be required to comply with the limits while they are operating 
across large areas of the open sea.

[[Page 69526]]

    We are also considering NOX emission controls for 
existing Category 3 engines that would begin in 2012. There are at 
least two approaches that could be used for setting NOX 
emission limits for existing engines. The first would be to set a 
performance standard, for example a reduction of about 20 percent from 
the Tier 1 NOX limits; how this reduction is achieved would 
be left up to the ship owner. Alternatively, the second approach would 
be to express the requirement as a specified action, for example an 
injector change known to achieve a particular reduction; this approach 
would simplify verification, but the emission reduction results may 
vary across engines. We will be exploring both of these alternative 
approaches and seek comment on the relative merits of each.

II. Why Is EPA Considering New Controls?

    Category 3 marine engines subject to today's ANPRM generate 
significant emissions of fine particulate matter (PM2.5), 
nitrogen oxides (NOX) and sulfur oxides (SOX) 
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 while SOX is a 
significant contributor to ambient PM2.5. These engines also 
emit volatile organic compounds (VOCs), carbon monoxide (CO), and 
hazardous air pollutants or air toxics, which are associated with 
adverse health effects. Diesel exhaust is of special public health 
concern, and since 2002 EPA has classified it as likely to be 
carcinogenic to humans by inhalation at environmental exposures. In 
addition, emissions from these engines also cause harm to public 
welfare, contributing to visibility impairment, and other detrimental 
environmental impacts across the U.S.

A. Ozone and PM Attainment

    Many of our nation's most serious ozone and PM2.5 
nonattainment areas are located along our coastlines where vessels 
using Category 3 marine engine emissions contribute to air pollution in 
or near urban areas where significant numbers of people are exposed to 
these emissions. The contribution of these engines to air pollution is 
substantial and is expected to grow in the future. Currently more than 
40 major U.S. ports \11\ along our Atlantic, Great Lakes, Gulf of 
Mexico, and Pacific coast lines are located in nonattainment areas for 
ozone and/or PM2.5 (See Figure II-1).
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    \11\ American Association of Port Authorities (AAPA), Industry 
Statistics, 2005 port rankings by cargo tonnage.
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    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 by 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, emissions from Category 3 marine engines impose public health and 
environmental costs on society. However, these added costs to society 
are not reflected in the costs of those using these engines and 
equipment. The market system itself cannot correct this negative 
externality because firms in the market are rewarded for minimizing 
their operating costs, including the costs of pollution control. In 
addition, firms that may take steps to use equipment that reduces air 
pollution may find themselves at a competitive economic disadvantage 
compared to firms that do not. The emission standards that EPA is 
considering for Category 3 marine diesel engines would help address 
this market failure and reduce the negative externality from these 
emissions by providing a positive incentive for engine manufacturers to 
produce engines that emit fewer harmful pollutants and for vessel 
builders and owners to use those cleaner engines.
    When considering vessel operations in the United States' Exclusive 
Economic Zone (EEZ), emissions from Category 3 marine engines account 
for a substantial portion of the United States' ambient 
PM2.5 and NOX mobile source emissions.\12\ We 
estimate that annual emissions in 2007 from these engines totaled more 
than 870,000 tons of NOX emissions and 66,000 tons of 
PM2.5. This represents more than 8 percent of U.S. mobile 
source NOX and 15 percent of U.S. mobile source 
PM2.5 emissions. These numbers are projected to increase 
significantly through 2030 due to growth in the use of Category 3 
marine engines to transport overseas goods to U.S. markets and U.S. 
produced goods overseas. Furthermore, their proportion of the emission 
inventory is projected to increase significantly as regulatory controls 
on other major emission categories take effect. By 2030, NOX 
emissions from these ships are projected to more than double, growing 
to 2.1 million tons a year or 34 percent of U.S. mobile source 
NOX emissions while PM2.5 emissions are expected 
to almost triple to 170,000 tons annually comprising 45 percent of U.S. 
mobile source PM2.5 emissions.\13\ In 2007 annual emission 
of SOX from Category 3 engines totaled almost 530,000 tons 
or more than half of mobile source SOX and by 2030 these 
emissions are expected to increase to 1.3 million tons or 94 percent of 
mobile source emissions.
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    \12\ In general, the United States Exclusive Economic Zone (EEZ) 
extends to 200 nautical miles from the U.S. coast. Exceptions 
include geographic regions near Canada, Mexico and the Bahamas where 
the EEZ extends less than 200 nautical miles from the U.S. coast. 
See map in Figure VIII-1, below.
    \13\ These projections are based on growth rates ranging from 
1.7 to 5.0 percent per year, depending on the geographic region. The 
growth rates are described in Section VIII.A.
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    Both ozone and PM2.5 are associated with 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, lost 
work days, and restricted activity days), increased respiratory 
symptoms, altered respiratory defense mechanisms, and chronic 
bronchitis. Diesel exhaust is of special public health concern, and 
since 2002 EPA has classified it as likely to be carcinogenic to humans 
by inhalation at environmental exposures.\14\
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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 
electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060. This document is available in Docket 
EPA-HQ-OAR-2007-0121.
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    Recent studies are showing that populations living near large 
diesel emission sources such as major roadways \15\, railyards, and 
marine ports \16\ are likely to experience greater diesel exhaust 
exposure levels than the overall U.S. population, putting them at 
greater health risks. As part of our current locomotive and marine 
diesel engine rulemaking (72 FR 15938, April 3, 2007), we are studying 
the U.S. population living near a sample of 47 marine ports which are 
located along the entire east and west coasts of the U.S. as well as 
the Gulf of Mexico and the Great Lakes region. This information

[[Page 69527]]

will be placed in the docket for this rulemaking when the study is 
completed. The PM2.5 and NOX reductions which 
would occur as a result of applying advanced emissions control 
strategies to Category 3 marine engines could both reduce the amount of 
emissions that populations near these sources are exposed to and assist 
state and local governments as they work to reduce NOX and 
PM2.5 inventories.
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    \15\ 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.
    \16\ 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. These documents are available in 
Docket EPA-HQ-OAR-2007-0121.
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    Today millions of Americans continue to live in areas that do not 
meet existing air quality standards. As of June 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 149 million people living in 94 areas (which include all 
or part of 391 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 PM2.5 or ozone NAAQS.
    Figure II-1 illustrates the widespread nature of these problems and 
depicts counties which are currently (as of March 2007) 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. Superimposed on this map are top U.S. 
ports many of which receive significant port stops from ocean going 
vessels operating with Category 3 marine engines. Currently more than 
40 major U.S. deep sea ports are located in these nonattainment areas. 
Many ports are located in areas rated as class I federal areas for 
visibility impairment and regional haze. It should be noted that 
emissions from ocean-going vessels are not simply a localized problem 
related only to cities that have commercial ports. Virtually all U.S. 
coastal areas are affected by emissions from ships that transit between 
those ports, using shipping lanes that are close to land. Many of these 
coastal areas also have high population densities. For example, Santa 
Barbara, which has no commercial port, estimates that engines on ocean-
going marine vessels currently contribute about 37 percent of total 
NOX in their area.\17\ These emissions are from ships that 
transit the area, and ``are comparable to (even slightly larger than) 
the amount of NOX produced onshore by cars and truck.'' By 
2015 these emissions are expected to increase 67 percent, contributing 
61 percent of Santa Barbara's total NOX emissions. This mix 
of emission sources led Santa Barbara to point out that they will be 
unable to meet air quality standards for ozone without significant 
emission reductions from these vessels, even if they completely 
eliminate all other sources of pollution. Interport emissions from OGV 
also contribute to other environmental problems, affecting sensitive 
marine and land ecosystems. As discussed above, EPA recently completed 
estimates of the contribution of Category 3 engines to emission 
inventories. We recognize that air quality effects may vary from one 
port/coastal area to another with differences in meteorology, because 
of spatial differences in emissions with ship movements within regional 
areas. In addition, these emissions may also affect adjacent coastal 
areas. For these reasons, we plan to study several different port areas 
to better assess the air quality effects of emissions from Category 3 
engines. We believe that there are additional port and adjacent coastal 
areas affected by emissions from Category 3 marine engines. We will be 
performing air quality modeling specific to this issue to better assess 
these impacts.

    \17\ Memorandum to Docket A-2001-11 from Jean-Marie Revelt, 
Santa Barbara County Air Quality News, Issue 62, July-August 2001 
and other materials provided to EPA by Santa Barbara County,'' March 
14, 2002.
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BILLING CODE 6560-50-P

[[Page 69528]]

[GRAPHIC] [TIFF OMITTED] TP07DE07.024

BILLING CODE 6560-50-C

[[Page 69529]]

    Emissions from Category 3 marine engines account for a substantial 
and growing portion of the U.S.'s coastal ambient PM2.5 and 
NOX levels. The emission reductions from tightened Category 
3 marine engine standards could play an important part in states' 
efforts to attain and maintain the NAAQS in the coming decades, 
especially in coastal nonattainment areas, where these engines comprise 
a large portion of the remaining NOX and PM2.5 
emissions inventories. For example, 2001 emission inventories for 
California's South Coast ozone and PM nonattainment areas \18\ indicate 
that ocean-going vessels (OGVs) contribute about 30 tons per day (tpd) 
of NOX and 2\1/2\ tpd of PM2.5 to regional 
inventories--and absent additional emission controls, this number would 
almost triple in 2020 to 86 tpd of NOX and 8 tpd of 
PM2.5 as port-related activities continue to grow. The 
Houston-Galveston-Beaumont area is also faced with growing OGV 
inventories which continue to hamper their area's effort to achieve and 
maintain clean air. Today, OGVs in the Houston nonattainment area 
annually contribute about 27 tpd of NOX emissions and this 
is projected to climb to 30 tpd by 2009.\19\ In the Corpus Christi 
area, OGVs in 2001 were responsible for about 16 tpd of 
NOX.\20\ Finally, in the New York/Northern New Jersey 
nonattainment area, 2000 inventories \21\ indicated that OGVs 
contributed 12 tpd of NOX emissions and about 0.75 tpd of 
PM2.5 emissions to PM inventories. We request comment on the 
impact Category 3 marine engines have on state and local emission 
inventories as well as their efforts to meet the ozone and 
PM2.5 NAAQS.
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    \18\ California Air Resources Board (2006). Emission Reduction 
Plan for Ports and Goods Movements, (April 2006) Appendix B-3, 
Available electronically at http://www.arb.ca.gov/gmp/docs/finalgmpplan090905.pdf.
    \19\ Texas Commission On Environmental Quality (2006) Houston-
Galveston-Brazoria 8-Hour Ozone State Implemental Plan & Rules, 
Informational Meeting Presentation, Kelly Keel, Air Quality Planning 
Section.
    \20\ Air Consulting and Engineering Solutions, Final Report 
Phase II Corpus Christi Regional Airshed, (August 2001) Project 
Number 21-01-0006.
    \21\ The Port Authority of New York & New Jersey, (2003), The 
New York, Northern New Jersey, Long Island Nonattainment Area 
Commercial Marine Vessel Emissions Inventory, Prepared by Starcrest 
Consulting Group, LLC.
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    Recently, new studies \22\ from the State of California provide 
evidence that PM2.5 emissions within marine ports contribute 
significantly to elevated ambient concentrations near these sources. A 
substantial number of people experience exposure to Category 3 marine 
engine emissions, raising potential health concerns. Additional 
information on marine port emissions and ambient exposures can be found 
in section II.B.3 of this ANPRM.
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    \22\ 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: ftp://ftp.arb.ca.gov/carbis/msprog/offroad/marinevess/documents/portstudy0406.pdf. These documents are 
available in Docket EPA-HQ-OAR-2007-0121.
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    In addition to public health impacts, there are serious public 
welfare and environmental impacts associated with ozone and 
PM2.5. Specifically, 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, 
SOX and PM2.5 can contribute to the substantial 
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 articles through soiling, and can contribute directly (or in 
conjunction with other pollutants) to structural damage by means of 
corrosion or erosion. Finally, NOX and SOX 
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), the Clean Air Nonroad Diesel Rule (69 FR 38957, June 29, 2004), 
the Heavy Duty Engine and Vehicle Standards and Highway Diesel Fuel 
Sulfur Control Requirements (66 FR 5002, Jan. 18, 2001), and the Tier 2 
Vehicle and Gasoline Sulfur Program (65 FR 6698, Feb. 10, 2000), the 
PM2.5 and NOX emission reductions resulting from 
tightened standards for Category 3 marine diesel engines would greatly 
assist nonattainment areas, especially along our nation's coasts, in 
attaining and maintaining the ozone and the PM2.5 NAAQS in 
the near term and in the decades to come.
    In September 2006, EPA finalized revised PM2.5 NAAQS. 
Nonattainment areas will be designated with respect to the revised 
PM2.5 NAAQS in early 2010. EPA modeling, conducted as part 
of finalizing the revised NAAQS, projects that in 2015 up to 52 
counties with 53 million people may violate the daily, annual, or both 
standards for PM2.5 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 PM2.5 inventory 
reductions that would be achieved from applying advanced emissions 
control strategies to Category 3 engines could be useful in helping 
coastal nonattainment areas, to both attain and maintain the revised 
PM2.5 NAAQS.
    State and local governments are 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 PM2.5 and 
NOX emissions by undertaking state level action.\23\ 
However, they also seek further Agency action for national standards, 
including the setting of stringent new Category 3 marine engine 
standards since states are preempted from setting new engine emissions 
standards for this class of engines.\24\
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    \23\ For example, see: California Air Resources Board (2006). 
Emission Reduction Plan for Ports and Goods Movements, (April 2006), 
Available electronically at http://www.arb.ca.gov/gmp/docs/finalgmpplan090905.pdf.
    \24\ For example, see letter dated November 29, 2006 from 
California Environmental Protection Agency to Administrator Stephen 
L. Johnson and January 20, 2006 letter from Executive Director, 
Puget Sound Clean Air Agency to Administrator Stephen L. Johnson.
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B. Public Health Impacts

1. Particulate Matter
    The emission control program for Category 3 marine engines has the 
potential to significantly reduce their contribution to 
PM2.5 inventories. In addition, these engines emit high 
levels of NOX which react in the atmosphere to form 
secondary PM2.5, ammonium nitrate. Category 3 marine engines 
also emit large amounts of SO2 and HC which react in the 
atmosphere to form secondary PM2.5 composed of sulfates and 
organic carbonaceous PM2.5. The emission control program 
being considered would reduce the contribution of Category 3 engines to 
both directly emitted diesel PM and secondary PM emissions.

[[Page 69530]]

(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). 
PM2.5 refers to fine particles, those 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). 
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 VOCs) 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 
through the atmosphere 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. (This air quality statistic compared to the standard is 
referred to as the ``design value.'') The annual standard specifies an 
expected annual arithmetic mean not to exceed 15[mu]g/m3 
averaged over three years. EPA has recently finalized PM2.5 
nonattainment designations for the 1997 standard (70 FR 943, Jan 5, 
2005).\25\ All areas currently in nonattainment for PM2.5 
will be required to meet these 1997 standards between 2009 and 2014.
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    \25\ 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 available in Docket EPA-HQ-OAR-2007-0121. This document is also 
available on the Web at: http://www.epa.gov/pmdesignations/.
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    EPA has recently amended the NAAQS for PM2.5 (71 FR 
61144, October 17, 2006). The final rule, signed on September 21, 2006 
and published in the Federal Register on October 17, 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 to provide increased protection 
against health effects associated with short-term exposures to fine 
particles. The current form of the 24-hour PM2.5 standard 
was retained (e.g., based on the 98th percentile concentration averaged 
over three years). The level of the annual PM2.5 NAAQS was 
retained at 15[mu]g/m3, continuing protection against health 
effects associated with long-term exposures. The current form of the 
annual PM2.5 standard was retained as an annual arithmetic 
mean averaged over three years, however, the following two aspects of 
the spatial averaging criteria were narrowed: (1) The annual mean 
concentration at each site shall be within 10 percent of the spatially 
averaged annual mean, and (2) the daily values for each monitoring site 
pair shall yield a correlation coefficient of at least 0.9 for each 
calendar quarter.
    With regard to the secondary PM2.5 standards, EPA has 
revised these standards to be identical in all respects to the revised 
primary standards. Specifically, EPA has revised the current 24-hour 
PM2.5 secondary standard by making it identical to the 
revised 24-hour PM2.5 primary standard and retained the 
annual PM2.5 secondary standard. This suite of secondary 
PM2.5 standards is intended to provide protection against 
PM-related public welfare effects, including visibility impairment, 
effects on vegetation and ecosystems, and material damage and soiling.
    The 2006 standards became effective on December 18, 2006. As a 
result of the 2006 PM2.5 standard, EPA will designate new 
nonattainment areas in early 2010. The timeframe for areas attaining 
the 2006 PM NAAQS will likely extend from 2015 to 2020.
(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.26 27 28
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    \26\ U.S. EPA (1996) Air Quality Criteria for Particulate 
Matter, EPA 600-P-95-001aF, EPA 600-P-95-001bF. This document is 
available in Docket EPA-HQ-OAR-2007-0121.
    \27\ 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-2007-0121.
    \28\ 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-2007-0121.
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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.\29\ In addition, a reanalysis of the American Cancer Society 
Study shows an association between fine particle and sulfate 
concentrations and lung cancer mortality.\30\ The Category 3 marine 
engines covered in this proposal contribute to both acute and chronic 
PM2.5 exposures.
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    \29\ 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.
    \30\ Pope Ca, III; Thun, MJ; Namboodiri, MM; Docery, DW; Evans, 
JS; Speizer, FE; Heath, CW. 1995. Particulate air pollution as a 
predictor of mortality in a prospective study of U.S. adults. Am J 
Respir Crit Care Med 151:669-674.
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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.\31\ Taking 
account of all air pollution sources, including both spark-ignition 
(gasoline) and diesel powered vehicles, these latter studies indicate 
that exposure to PM2.5 emissions near roadways, 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.\32\ Also, a 
number of studies have shown associations between residential or school 
outdoor concentrations of some

[[Page 69531]]

constituents of fine particles found in motor vehicle exhaust and 
adverse respiratory outcomes, including asthma prevalence in children 
who live near major roadways.33 34 35 Although the engines 
considered in this proposal differ with 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 
Category 3 marine engines. By reducing their contribution to 
PM2.5 inventories, the emissions controls under 
consideration also would reduce exposure to these emissions, 
specifically exposure near marine ports and shipping routes.
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    \31\ Riekider, M.; Cascio, W.E.; Griggs, T.R.; Herbst, M.C.; 
Bromberg, P.A.; Neas, L.; Williams, R.W.; Devlin, R.B. (2003) 
Particulate Matter Exposures in Cars is Associated with 
Cardiovascular Effects in Healthy Young Men. Am. J. Respir. Crit. 
Care Med. 169: 934-940.
    \32\ 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.
    \33\ 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.
    \34\ 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.
    \35\ 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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2. Ozone
    The emissions reduction program under consideration for Category 3 
marine engines would reduce the contribution of these engines 
NOX inventories. These engines currently have high 
NOX emissions due to the size of the engine and because they 
are relatively uncontrolled. NOX contributes 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 formed by the reaction of VOCs and 
NOX in the atmosphere in the presence of heat and sunlight. 
These two 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.\36\ 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 would 
occur on a single high-temperature day. Ozone also can be transported 
from pollution sources into areas hundreds of miles downwind, resulting 
in elevated ozone levels even in areas with low local VOC or 
NOX emissions.
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    \36\ U.S. EPA Air Quality Criteria for Ozone and Related 
Photochemical Oxidants (Final). U.S. Environmental Protection 
Agency, Washington, D.C., EPA 600/R-05/004aF-cF, 2006. This document 
may be accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html. This document is available in 
Docket EPA-HQ-OAR-2007-0121.
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    The highest levels of ozone are produced when both VOC and 
NOX emissions are present in significant quantities on clear 
summer days. Relatively small amounts of NOX enable ozone to 
form rapidly when VOC levels are relatively high, but ozone production 
is quickly limited by removal of the NOX. Under these 
conditions NOX reductions are highly effective in reducing 
ozone while VOC reductions have little effect. Such conditions are 
called ``NOX-limited''. Because the contribution of VOC 
emissions from biogenic (natural) sources to local ambient ozone 
concentrations can be significant, even some areas where man-made VOC 
emissions are relatively low can be NOX limited.
    When NOX levels are relatively high and VOC levels 
relatively low, NOX forms inorganic nitrates (i.e., 
particles) but relatively little ozone. Such conditions are called 
``VOC-limited.'' Under these conditions, VOC reductions are effective 
in reducing ozone, but NOX reductions can actually increase 
local ozone under certain circumstances. Even in VOC-limited urban 
areas, NOX reductions are not expected to increase ozone 
levels if the NOX reductions are sufficiently large.
    Rural areas are usually NOX-limited, due to the 
relatively large amounts of biogenic VOC emissions in many rural areas. 
Urban areas can be either VOC- or NOX-limited, or a mixture 
of both, in which ozone levels exhibit moderate sensitivity to changes 
in either pollutant. Ozone concentrations in an area also can be 
lowered by the reaction of nitric oxide with ozone, forming nitrogen 
dioxide (NO2); as the air moves downwind and the cycle 
continues, the NO2 forms additional ozone. The importance of 
this reaction depends, in part, on the relative concentrations of 
NOX, VOC, and ozone, all of which change with time and 
location.
    The current ozone NAAQS 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 public health and welfare.\37\ The final ozone NAAQS rule is 
scheduled for March 2008.
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    \37\ EPA proposes to set the 8-hour primary ozone standard to a 
level within the range of 0.070-0.075 ppm. The agency also requests 
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 proposes 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 is proposing 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 papers.\38\ \39\ 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, and breathing may 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 a 
doctor's attention and/or the use of additional medication. 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

[[Page 69532]]

exposure to ozone include children, the elderly, and individuals with 
respiratory disease such as asthma. As of the 2006 review, there was 
suggestive evidence that certain people may have greater genetic 
susceptibility. Those with greater exposures to ozone, for instance due 
to time spent outdoors (e.g., children and outdoor workers), are also 
of concern.
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    \38\ U.S. EPA Air Quality Criteria for Ozone and Related 
Photochemical Oxidants (Final). U.S. Environmental Protection 
Agency, Washington, D.C., EPA 600/R-05/004aF-cF, 2006. This document 
is available in Docket EPA-HQ-OAR-2007-0121. This document may be 
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.
    \39\ U.S. EPA (2006) Review of the National Ambient Air Quality 
Standards for Ozone, Policy Assessment of Scientific and Technical 
Information. OAQPS Staff Paper Second Draft.EPA-452/D-05-002. This 
document is available in Docket EPA-HQ-OAR-2007-0121. This document 
is available electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp.html.
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    The recent ozone AQCD also examined relevant new scientific 
information which has emerged in the past decade, including the impact 
of ozone exposure on such health effect indicators 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.
3. Air Toxics
    People experience elevated risk of cancer and other noncancer 
health effects from exposure to 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 Category 3 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 the other air toxic substances 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.\40\ 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; \41\ however, the confidence in the 
RfC for acrolein is medium \42\ and confidence in NATA estimates of 
population noncancer hazard from ambient exposure to this pollutant is 
low.\43\ 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 with particulate matter concentration.
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    \40\ 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, 
that 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.
    \41 \ U.S. EPA. 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.
    \42\ U.S. EPA (2003) Integrated Risk Information System File of 
Acrolein. National Center for Environmental Assessment, Office of 
Research and Development, Washington, DC 2003. This material is 
available electronically at http://www.epa.gov/iris/subst/0364.htm.
    \43\ 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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    It should be noted that 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 Web site.\44\ 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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    \44\ 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 Category 3 marine 
engines, and provides a discussion of the health risks associated with 
each air toxic.
(a) Diesel Exhaust (DE)
    Category 3 marine engines emit diesel exhaust (DE), a complex 
mixture comprised of carbon dioxide, oxygen, nitrogen, water vapor, 
carbon monoxide, nitrogen compounds, sulfur compounds and numerous low-
molecular-weight hydrocarbons. A number of these gaseous hydrocarbon 
components are individually known to be toxic including aldehydes, 
benzene and 1,3-butadiene. The diesel particulate matter (DPM) present 
in diesel exhaust consists of fine particles (< 2.5 [mu]m), including a 
subgroup with a large number of ultrafine particles (< 0.1 [mu]m). 
These particles have large surface area which makes them an excellent 
medium for adsorbing organics and their small size makes them highly 
respirable and able to reach the deep lung. Many of the organic 
compounds present on the particles and in the gases are individually 
known to have mutagenic and carcinogenic properties. Diesel exhaust 
varies significantly in chemical composition and particle sizes between 
different engine types (heavy-duty, light-duty), engine operating 
conditions (idle, accelerate, decelerate), and fuel formulations (high/
low sulfur fuel).\45\ 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.
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    \45\ U.S. EPA (2002) Health Assessment Document for Diesel 
Engine Exhaust. EPA/600/8-90/057F Office of Research and 
Development, Washington DC. Pp1-1 1-2. This document is available in 
Docket EPA-HQ-OAR-2007-0121. This document is available 
electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
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(1) Diesel Exhaust: Potential Cancer Effect of Diesel Exhaust
    In EPA's 2002 Diesel Health Assessment Document (Diesel HAD),\46\ 
diesel exhaust was classified as likely to be carcinogenic to humans by 
inhalation at 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

[[Page 69533]]

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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    \46\ 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-2007-0121.
    This document is available electronically at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
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    For the Diesel HAD, EPA reviewed 22 epidemiologic studies on the 
subject of the carcinogenicity of workers exposed to diesel exhaust in 
various occupations, finding increased lung cancer risk, although not 
always statistically significant, in 8 out of 10 cohort studies and 10 
out of 12 case-control studies within several industries, including 
railroad workers. Relative risk for lung cancer associated with 
exposure ranged from 1.2 to 1.5, although a few studies show relative 
risks as high as 2.6. Additionally, the Diesel HAD also relied on two 
independent meta-analyses, which examined 23 and 30 occupational 
studies respectively, which found statistically significant increases 
in smoking-adjusted relative lung cancer risk associated with 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.47 48 49
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    \47\ U.S. EPA (2002) Health Assessment Document for Diesel 
Engine Exhaust. EPA/6008-90/057F Office of Research and Development, 
Washington DC. This document is available in Docket EPA-HQ-OAR-2007-
0121.
    \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- 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 diesel exhaust is a likely human 
carcinogen. 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.
(2) Diesel Exhaust: Other Health Effects
    Noncancer health effects of acute and chronic exposure to diesel 
exhaust emissions are also of concern to the Agency. EPA derived an 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/m\3\ 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 were found to be 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).
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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.
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(3) Ambient PM2.5 Levels and Exposure to Diesel Exhaust PM
    The Diesel HAD briefly summarizes health effects associated with 
ambient PM and discusses the EPA's annual NAAQS of 15 [mu]g/m\3\. In 
addition, both the 2004 AQCD and the 2005 Staff Paper for PM2.5 
have more recent information. 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, of which diesel PM is a constituent.
(4) 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 Category 3 marine 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 resulting in a wide range of exposures 
from 2 to 1,280 [mu]g/m\3\ 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).\54\ 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.
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    \54\ 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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[[Page 69534]]

Elevated Concentrations and Ambient Exposures in Mobile Source-Impacted 
Areas
    Regions immediately downwind of marine ports and shipping channels 
experience elevated ambient concentrations of directly-emitted 
PM2.5 from Category 3 marine engines. Due to the unique 
nature of marine ports, emissions from a large number of Category 3 
marine engines are concentrated in a relatively small area.
    A recent 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.\55\ This is relevant in that locomotives 
use diesel engines similar to those used in marine vessels. 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 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/m\3\ 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 rail yard 
emissions.
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    \55\ 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]
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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.\56\ The study found 
that ocean going vessels comprised 53% of the diesel PM emissions while 
ship auxiliary engines' hoteling comprised another 20% of PM emissions 
for the marine ports. Like the earlier rail yard study, the port study 
employed the ISCST3 dispersion model. Also 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/m\3\ of diesel PM, and about 50,000 people lived in 
areas with at least 1.5 ug/m\3\ of ambient diesel PM directly from the 
port. The study found that impacts could be discerned up to 15 miles 
from the marine port.
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    \56\ Di, P.; Servin, A.; Rosenkranz, K.; Schwehr, B.; Tran, H. 
(2006) Diesel particulate matter exposure assessment study for the 
Ports of Los Angeles and Long Beach. California Air Resources Board. 
[Online at http://www.arb.ca.gov/msprog/offroad/marinevess/marinevess.htm]
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    Overall, while these studies focus on only two large marine port 
and railroad facilities, they highlight the substantial contribution 
these facilities make to elevated ambient concentrations in populated 
areas.
    We initiated a study in 2006 to better understand the populations 
that are living near rail yards and marine ports nationally. As part of 
this effort, a computer geographic information system (GIS) is being 
used to identify the locations and property boundaries of these 
facilities nationally, and to determine the size and demographic 
characteristics of the population living near these facilities. We 
anticipate that the results of this study will be completed in late 
2007 and we intend to add this report to the public docket.
(b) Other Air Toxics-Benzene, 1,3-butadiene, Formaldehyde, 
Acetaldehyde, Acrolein, POM, Naphthalene
    Category 3 marine engine emissions contribute to ambient levels of 
other air toxics known or suspected as human or animal carcinogens, or 
that have non-cancer health effects. These other compounds 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 
risk drivers in the 1999 National-Scale Air Toxics Assessment (NATA). 
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. Furthermore, a significant portion of 
total nationwide emissions of these pollutants result from mobile 
sources. However, EPA does not have high confidence in the NATA data 
for all these compounds. Reducing the emissions from Category 3 marine 
engines would help reduce exposure to these harmful substances.
    Air toxics can cause a variety of cancer and noncancer health 
effects. A number of the mobile source air toxic pollutants described 
in this section are known or likely to pose a cancer hazard in humans. 
Many of these compounds also cause adverse noncancer health effects 
resulting from inhalation exposures. These include neurological, 
cardiovascular, liver, kidney, and respiratory effects as well as 
effects on the immune and reproductive systems.

C. Other Environmental Effects

    There are a number of public welfare effects associated with the 
presence of ozone and PM2.5 in the ambient air including the 
impact of PM2.5 on visibility 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. Visibility impairment manifests in two 
principal ways: as local visibility impairment and as regional 
haze.\57\ Local visibility impairment may take the form of a localized 
plume, a band or layer of discoloration appearing well above the 
terrain as a result of complex local meteorological conditions. 
Alternatively, local visibility impairment may manifest as an urban 
haze, sometimes referred to as a ``brown cloud.'' This urban haze is 
largely caused by emissions from multiple sources in the urban areas 
and is not typically attributable to only one nearby source or to long-
range transport. The second type of visibility impairment, regional 
haze, usually results from multiple pollution sources spread over a 
large geographic region. Regional haze can impair visibility in large 
regions and across states.
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    \57\ See discussion in U.S. EPA , National Ambient Air Quality 
Standards for Particulate Matter; Proposed Rule; January 17, 2006, 
Vol71 p 2676. This document is available in Docket EPA-HQ-OAR-2007-
0121. This information is available electronically at http://epa.gov/fedrgstr/EPA-AIR/2006/January/Day-17/a177.pdf.
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    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

[[Page 69535]]

see the final 2004 PM AQCD \58\ as well as the 2005 PM Staff Paper.\59\
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    \58\ 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-2007-0121.
    \59\ 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-2007-0121.
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    Fine particles are the major cause of reduced visibility in parts 
of the United States. EPA is pursuing a two-part strategy to address 
visibility. First, to address the welfare effects of PM on visibility, 
EPA set secondary PM2.5 standards which would act in 
conjunction with the establishment of a regional haze program. In 
setting this secondary standard EPA 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 38680-38681, July 18, 1997).\60\ 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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    \60\ 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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    Category 3 marine engines contribute to visibility concerns in 
these areas through their primary PM2.5 emissions and their 
NOX and SO2 emissions which contribute to the 
formation of secondary PM2.5.
    Recently designated PM2.5 nonattainment areas indicate 
that, as of June 20, 2007, almost 90 million people live in 
nonattainment areas for the 1997 PM2.5 NAAQS. Thus, at least 
these populations would likely be experiencing visibility impairment, 
as well as many thousands of individuals who travel to these areas. 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. In summary, visibility impairment is 
experienced throughout the U.S., in multi-state regions, urban areas, 
and remote mandatory class I federal areas.61 62
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    \61\ 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 available in Docket EPA-HQ-OAR-2007-0121. This document is also 
available on the web at: http://www.epa.gov/pmdesignations/.
    \62\ U.S. EPA. Regional Haze Regulations, July 1, 1999. (64 FR 
35714, July 1, 1999) This document is available in Docket EPA-HQ-
OAR-2007-0121.
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2. Plant and Ecosystem Effects of Ozone
    Ozone contributes to many 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 lower 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 
ozone Air Quality Criteria Document (ozone AQCD) \63\ presents more 
detailed information on ozone effects on vegetation and ecosystems.
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    \63\ 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-2007-0121. This document may be 
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.
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    As discussed above, Category 3 marine engine emissions of 
NOX contribute to ozone and therefore the NOX 
standards discussed in this action would help reduce crop damage and 
stress on vegetation from ozone.
3. Acid Deposition
    Acid deposition, or acid rain as it is commonly known, occurs when 
NOX and SO2 react in the atmosphere with water, 
oxygen and oxidants to form various acidic compounds that later fall to 
earth in the form of precipitation or dry deposition of acidic 
particles. It contributes to damage of trees at high elevations and in 
extreme cases may cause lakes and streams to become so acidic that they 
cannot support aquatic life. In addition, acid deposition accelerates 
the decay of building materials and paints, including irreplaceable 
buildings, statues, and sculptures that are part of our nation's 
cultural heritage.
    The proposed NOX and SOX standards would help 
reduce acid deposition, thereby helping to reduce acidity levels in 
lakes and streams throughout the coastal areas of our country and help 
accelerate the recovery of acidified lakes and streams and the revival 
of ecosystems adversely affected by acid deposition. Reduced acid 
deposition levels will also help reduce stress on forests, thereby 
accelerating reforestation efforts and improving timber production. 
Deterioration of historic buildings and monuments, vehicles, and other 
structures exposed to acid rain and dry acid deposition also will be 
reduced, and the costs borne to prevent acid-related damage may also 
decline. While the reduction in nitrogen acid deposition will be 
roughly proportional to the reduction in NOX emissions, the 
precise impact of new standards would differ across different areas.
4. Eutrophication and Nitrification
    The NOX standards discussed in this action would help 
reduce the airborne nitrogen deposition that contributes to 
eutrophication of watersheds, particularly in aquatic systems where 
atmospheric deposition of nitrogen represents a significant portion of 
total nitrogen loadings. Eutrophication is the accelerated production 
of organic matter, particularly algae, in a water body. This increased 
growth can cause numerous adverse ecological effects and economic 
impacts, including nuisance algal blooms, dieback of underwater plants 
due to reduced light penetration, and toxic plankton blooms. Algal and 
plankton blooms can also reduce the level of dissolved oxygen, which 
can adversely affect fish and shellfish populations. In recent decades, 
human activities have greatly accelerated nutrient impacts, such as 
nitrogen and phosphorus, causing excessive growth of algae and leading 
to degraded water

[[Page 69536]]

quality and associated impairment of freshwater and estuarine resources 
for human uses.\64\
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    \64\ Deposition of Air Pollutants to the Great Waters, Third 
Report to Congress, June 2000, EPA-453/R-00-005. This document is 
available in Docket EPA-HQ-OAR-2007-0121. It is also available at 
http://www.epa.gov/oar/oaqps/gr8water/3rdrpt/obtain.html.
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    Severe and persistent eutrophication often directly impacts human 
activities. For example, losses in the nation's fishery resources may 
be directly caused by fishkills associated with low dissolved oxygen 
and toxic blooms. Declines in tourism occur when low dissolved oxygen 
causes noxious smells and floating mats of algal blooms create 
unfavorable aesthetic conditions. Risks to human health increase when 
the toxins from algal blooms accumulate in edible fish and shellfish, 
and when toxins become airborne, causing respiratory problems due to 
inhalation. According to the NOAA report, more than half of the 
nation's estuaries have moderate to high expressions of at least one of 
these symptoms--an indication that eutrophication is well developed in 
more than half of U.S. estuaries.\65\
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    \65\ Bricker, Suzanne B., et al., National Estuarine 
Eutrophication Assessment, Effects of Nutrient Enrichment in the 
Nation's Estuaries, National Ocean Service, National Oceanic and 
Atmospheric Administration, September, 1999.
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5. 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.\66\ 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. The PM standards discussed in this 
action would help reduce the airborne particles that contribute to 
materials damage and soiling.
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    \66\ 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-2007-0121.
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III. Relevant Clean Air Act Provisions

    Section 213 of the Clean Air Act (the Act) gives us the authority 
to establish emission standards for nonroad engines and vehicles. 
Section 213(a)(3) requires the Administrator to set (and from time to 
time revise) standards for NOX, VOCs, or carbon monoxide 
emissions from new nonroad engines, to reduce ambient levels of ozone 
and carbon monoxide. That section specifies that the ``standards shall 
achieve the greatest degree of emission reductions achievable through 
the application of technology which the Administrator determines will 
be available for the engines or vehicles.'' As part of this 
determination, the Administrator must give appropriate consideration to 
lead time, noise, energy, and safety factors associated with the 
application of such technology. Section 213(a)(4) authorizes the 
Administrator to establish standards on new engines to control 
emissions of pollutants, such as PM, which ``may reasonably be 
anticipated to endanger public health and welfare.'' In setting 
appropriate standards, EPA is instructed to take into account costs, 
noise, safety, and energy factors.
    Section 211(c) of the CAA allows us to regulate fuels where 
emission products of the fuel either: (1) Cause or contribute to air 
pollution that reasonably may be anticipated to endanger public health 
or welfare, or (2) will impair to a significant degree the performance 
of any emission control device or system which is in general use, or 
which the Administrator finds has been developed to a point where in a 
reasonable time it will be in general use were such a regulation to be 
promulgated.

IV. International Regulation of Air Pollution From Ships

    Annex VI to the International Convention for the Prevention of 
Pollution from Ships (MARPOL) addresses air pollution from ships. Annex 
VI was adopted by the Parties to MARPOL at a Diplomatic Conference on 
September 26, 1997, and it went into force May 20, 2005. As of July 31, 
2007, the Annex has been ratified by 44 countries, representing 74.1 
percent of the world's merchant shipping tonnage.\67\
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    \67\ See http://www.imo.org Go to Conventions, Status of 
Conventions--Summary.
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    Globally harmonized regulation of ship emissions is generally 
recognized to be the preferred approach for addressing air emissions 
from ocean-going vessels. It reduces costs for ship owners, since they 
would not be required to comply with a patchwork of different standards 
that could occur if each country was setting its own standards, and it 
can simplify environmental protection for port and coastal states.
    The significance of international shipping to the United States can 
be illustrated by port entrance statistics. In 1999, according to U.S. 
Maritime Administration (MARAD) data, about 90 percent of annual 
entrances to U.S. ports were made by foreign-flagged vessels (75,700 
total entrances; 67,500 entrances by foreign vessels; entrances are for 
vessels engaged in foreign trade and do not include Jones Act \68\ 
vessels). At the same time, however, only a small portion of those 
vessels account for most of the visits. In 1999, of the 7,800 foreign 
vessels that visited U.S. ports, about 12 percent accounted for about 
50 percent of total vessel entrances; about 30 percent accounted for 
about 75 percent of the vessel entrances.\69\
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    \68\ 46 USCS Appx Sec.  688.
    \69\ Final Regulatory Support Document: Control of Emissions 
from New Marine Compression-Ignition Engines at or Above 30 Liters 
per Cylinder. EPA420-R-03-004, January 2003, pg. 3-50. This document 
is available at http://www.epa.gov/otaq/regs/nonroad/marine/ci/r03004.pdf. We will update these statistics for more recent years; 
however, these results are not expected to change significantly 
given the U.S. share of the ownership of ocean-going vessels. MARAD 
data from 2005 indicates that while about 4.7 percent of all ocean-
going vessels are owned by citizens of the United States (5th 
largest fleet) only about 1.9 percent of all ocean-going vessels are 
flagged here. Also according to that data, while Greece, Japan, 
China, and Germany account for the largest fleets in terms of 
ownership (15.3, 13.0, 11, and 8.9 percent, respectively), Panama 
and Liberia account for the largest fleets by flag (21.6 and 8.9 
percent, respectively).
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    The emission control program contained in Annex VI was the first 
step for the international control of air pollution from ships. 
However, as early as the 1997 conference, many countries ``already 
recognized that the NOX emission limits established in 
Regulation 13 were very modest when compared with current technology 
developments.'' \70\ Consequently, a Conference Resolution was adopted 
at the 1997 conference that invited the Marine Environment Protection 
Committee (MEPC) to review the NOX emission limits at a 
minimum of five-year intervals after entry into force of the protocol 
and, if appropriate, amend

[[Page 69537]]

the NOX limits to reflect more stringent controls.
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    \70\ Proposal to Initiate a Revision Process, Submitted by 
Finland, Germany, Italy, the Netherlands, Norway, Sweden and the 
United Kingdom. MEPC 53/4/4, 15 April 2005. Marine Environment 
Protection Committee, 53rd Session, Agenda Item 4.
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    The United States began advocating a review of the NOX 
emission limits in 1999.\71\ However, MEPC did not formally consider 
the issue until 2005, after the Annex went into effect. Negotiations 
for amendments to the Annex VI standards, including NOX and 
SOX emission limits, officially began in April 2006, with 
the most recent round of negotiations taking place in April 2007. The 
United States submitted a paper to that meeting (April 2007 Bulk 
Liquids and Gases Sub-Committee meeting, referred to as BLG-11) setting 
out an approach for new international engine and fuel standards. That 
approach forms the basis of the program outlined in this ANPRM.\72\ 
Discussions are expected to continue through Summer 2008 and are 
expected to conclude at the October 2008 MEPC meeting. We will continue 
to coordinate our national rule for Category 3 emission limits with our 
activities at IMO.
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    \71\ Revision of the NOX Technical Code, Tier 2 
Emission Limits for Diesel Marine Engines At or Above 130 kW, 
submitted by the United States. MEPC 44/11/7, 24 December 1999. 
Marine Environment Protection Committee, 44th Session, Agenda Item 
11.
    \72\ ``Revision of the MARPOL Annex VI, the NOX 
Technical Code and Related Guidelines; Development of Standards for 
NOX, PM, and SOX,'' submitted by the United 
States, BLG 11/5, Sub-Committee on Bulk Liquids and Gases, 11th 
Session, Agenda Item 5, February 9, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0034. This document is also available on our Web site: http://www.epa.gov/otaq/oceanvessels.com.
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V. Potential Standards and Effective Dates

    Over the past several years, remarkable progress has been made for 
land-based highway and nonroad diesel engines in reducing 
NOX and PM emissions. Current EPA standards for those land-
based sources are anticipated to achieve emission reductions of more 
than 90 percent relative to uncontrolled NOX and PM levels. 
In contrast, Category 3 marine engines are subject to modest 
NOX standards only. In this rulemaking, we are considering a 
comprehensive program that would set long-term standards based on the 
use of high-efficiency catalytic aftertreatment. These standards would 
achieve substantial reductions in NOX, PM, and 
SOX exhaust emissions.
    The program we are considering is based on the the U.S. Government 
proposal to IMO, which consists of near- and long-term NOX 
limits for new engines based on engine controls and aftertreatment 
technology; NOX limits for certain existing engines based on 
engine controls; and PM/SOX limits that can be achieved 
through the use of exhaust gas cleaning or low sulfur fuel. To reduce 
the costs of the international program, the long-term new engine 
NOX limits and the PM/SOX limits would not apply 
while ships are operating on the open ocean; instead, they would in 
specified geographic areas to be defined under the treaty.
    This section describes in greater detail how we are considering 
that emission control program for our federal action under the Clean 
Air Act.

A. NOX Standards

    Tier 2 NOX limits: We are considering new NOX emission 
standards for Category 3 marine diesel engines. As discussed in Section 
VI, emission control technology for Category 3 marine engines has 
progressed substantially in recent years. Significant reductions can be 
achieved in the near term through in-cylinder controls with little or 
no impact on overall vessel performance. These technologies include 
traditional engine-out controls such as electronically controlled high 
pressure common-rail fuel systems, turbocharger optimization, 
compression-ratio changes, and electronically controlled exhaust 
valves. Further emission reductions could be achieved through the use 
of water-based technologies such as water emulsification, direct water 
injection, or intake-air humidification or through exhaust gas 
recirculation. We request comment on setting a near term NOX 
emission standard requiring a reduction of 15 to 25 percent below the 
current Tier 1 standard. We are considering applying this near term 
standard to new engines as early as 2011.
    Tier 3 NOX limits: In the longer term, we believe that much greater 
emission reductions could be achieved through the use of selective 
catalytic reduction (SCR). More than 300 SCR systems have been 
installed on marine vessels, some of which have been in operation for 
more than 10 years and have accumulated 80,000 hours of operation. 
While many of these applications have been limited to certain vessel 
classes, we believe that the technology is feasible for application to 
most engines given adequate lead time. As discussed in Section VI, SCR 
systems are capable of reducing NOX on the order of 90 to 95 
percent compared to current emission levels. We further believe that an 
80 percent reduction from the Tier 2 levels discussed above is 
achievable throughout the life of the vessel. We are requesting comment 
on setting a NOX standard 80 percent below the Tier 2 
standards in the 2016 timeframe. Low sulfur distillate fuel would help 
in achieving these limits due to the impact of sulfur on catalyst 
operation; however, we do not believe low sulfur fuel is necessary to 
achieve these reductions. SCR systems have been used on residual fuel, 
with sulfur levels as high as 2.5 to 3 percent. However low sulfur 
distillate fuel would allow SCR systems to be smaller, more efficient, 
less costly, and simpler to operate.
    NOX limits for existing engines: Due to the very long life of 
ocean-going vessels and the availability of known in-cylinder technical 
modifications that provide significant and cost-effective 
NOX reductions, the U.S. proposal to IMO presents potential 
NOX emission limits for engines on vessels built prior to 
the Tier 1 limits. We are requesting comment on requiring engines on 
these vessels to be retrofitted to meet the Tier 1 standard. The U.S. 
submittal proposed that this requirement would start in 2012. Although 
the Tier 1 standards went into effect in the United States in 2004, 
manufacturers have been building engines with emissions that meet this 
limit since 2000 due to the MARPOL Annex VI NOX standard. 
Although the Annex VI standards did not go into force until 2005, they 
apply to engines installed on vessels built on or after January 1, 
2000.
    Engines may be retrofitted to achieve meaningful emission reduction 
by applying technology used by manufacturers to meet the Tier 1 limits. 
These technologies include slide-valve fuel injectors and injection 
timing retard. Manufacturers have indicated that they can reduce 
NOX emissions by approximately 20 percent using this 
technology. However, some engines have higher baseline emissions than 
average and would require more than a 20 percent emission reduction to 
meet Tier 1 standards. Manufacturers have expressed concerns that they 
would not necessarily be able to reduce emissions to the Tier 1 
standards for such engines through a simple retrofit. Therefore, the 
U.S. proposal to IMO considers a standard based on percent reduction 
rather than an absolute numerical limit. Specifically, these engines 
would need to be modified to reduce NOX emissions by 20 
percent from their existing baseline emission rate. Alternatively, we 
request comment on requiring vessel operators to perform a specific 
action, such as a valve or injector change, that would be known to 
achieve a particular NOX reduction. In this case, the 
certification and compliance provisions would be based on the 
completion of this action rather than achieving a specified emission 
reduction.
    Over time, engine manufacturers have changed their engine platforms 
as new

[[Page 69538]]

technologies have become available. Many of the technologies that can 
be used to reduce NOX emissions on modern engines may not be 
easily applied to older engine designs. Based on conversations with 
engine manufacturers we believe that engines built in the mid-1980s and 
later are compatible with the lower NOX components. 
Therefore we are requesting comment on excluding engines installed on a 
vessel prior to 1985 from this requirement. We request comment on what 
generation of engines can be retrofitted to achieve NOX 
reductions. Also, we request comment on the feasibility, costs, and 
other business impacts that would result from retrofitting existing 
engines to meet a NOX standard as discussed above.

B. PM and SOX Standards

    For PM and SOX emission control, we are considering 
emission performance standards that would reflect the use of low-sulfur 
distillate fuels or the use of exhaust gas cleaning technology, or a 
combination of both. As discussed in Section VI, SOX 
emissions and the majority of the direct PM emissions from Category 3 
marine engines operated on residual fuels are a direct result of fuel 
quality, most notably the sulfur in the fuel. In addition, 
SOX emissions form secondary PM in the atmosphere. Other 
components of residual fuel, such as ash and heavy metals, also 
contribute directly to PM. Significant PM and SOX reductions 
could be achieved by using low sulfur fuel residual fuel or distillate 
fuel. Alternatively, direct and indirect sulfur-based PM can be reduced 
through the use of a seawater scrubber in the exhaust system. Recent 
demonstration projects have shown that scrubbers are capable of 
reducing SOX emissions on the order of 95 percent and can 
achieve substantial reductions in PM as well.
    We request comment on setting a PM standard on the order of 0.5 g/
kW-hr and a SOX standard on the order of 0.4 g/kW-hr. We 
believe that the combination of these two performance-based standards 
would be a cost-effective way to approach both primary and secondary PM 
emission reductions because ship owners would have a variety of 
mechanisms to achieve the standard, including fuel switching or the use 
of emission scrubbers. This standard would apply as early as 2011 and 
would result in more than a 90 percent reduction in SOX and 
approximately a 50-70 percent reduction in PM. We request comment on 
performance based PM and SOX standards for Category 3 marine 
engines, what the standards should be, and an appropriate 
implementation date. We also request comment on allowing vessel 
operators the option to comply with the standards by simply using a 
distillate fuel with a maximum allowable sulfur level, such as 1,000 
ppm. Under this option, no exhaust emission testing would be required 
to demonstrate compliance with the standard.

VI. Emission Control Technology

A. Engine-Based NOX Control

1. Traditional In-Cylinder Controls
    Engine manufacturers are meeting the Tier 1 NOX 
standards \73\ for Category 3 marine engines today through traditional 
in-cylinder fuel and air management approaches. These in-cylinder 
emission control technologies include electronic controls, optimizing 
the turbocharger, higher compression ratio, valve timing, and optimized 
fuel injection which may include common rail systems, timing retard, 
increased injection pressure, rate shaping, and changes to the number 
and size of injector holes to increase fuel atomization. Although U.S. 
standards became effective in 2004, most manufacturers began selling 
marine engines in 2000 that met the MARPOL Annex VI NOX 
standard in anticipation of its ratification.
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    \73\ This NOX standard is the same as the 
internationally negotiated NOX standards established by 
the International Maritime Organization (IMO) in Annex VI to the 
International Convention on the Prevention of Pollution from Ships, 
1973, as Modified by the Protocol of 1978 Relating Thereto (MARPOL).
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    Manufacturers have indicated that they would be able to use in-
cylinder engine control strategies to achieve further NOX 
emission reductions beyond the Tier 1 standards. EUROMOT, which is an 
association of engine manufacturers, submitted a proposal to the 
International Maritime Organization for new Category 3 marine engine 
NOX standards 2 g/kW-hr below the Tier 1 NOX 
standard.\74\ In this submission, they pointed to the following 
technologies for Category 3 marine engines operating on residual fuel: 
Fuel injection timing, high compression ratio, modified valve timing on 
4-stroke engines, late exhaust valve closing on 2-stroke engines, and 
optimized fuel injection system and combustion chamber. EUROMOT stated 
that the limiting factors for NOX design and optimization 
are increases in low load smoke and thermal load, PM and CO2 
emissions, fuel consumption, and concerns about engine reliability and 
load acceptance. We request comment on potential emission reductions 
beyond the Tier 1 NOX standards that may be achieved through 
traditional in-cylinder technology and what the impact of the low 
NOX designs would be on fuel consumption, maintenance, and 
on PM exhaust emissions.
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    \74\ ``MARPOL Annex VI Revision--Proposals Related to Future 
Emission Limits and Issues for Clarification,'' Submitted by EUROMOT 
to the IMO Subcommittee on Bulk Liquids and Gases, BLG 10/14/12, 
January 26, 2006, Docket ID EPA-HQ-OAR-2007-0121-0014.
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    Many of the same in-cylinder control technologies used to meet the 
Tier 1 NOX standards can be used as retrofit technology on 
existing engines built prior to the Tier 1 standards. An example of 
this is retrofitting older fuel injectors with new injectors using 
slide-valve nozzle tips. The slide-valve in the nozzle tip limits fuel 
``dripping'' which leads to higher HC, PM, and smoke emissions and 
engine fouling. This fuel nozzle can be combined with low-
NOX engine calibration to achieve about a 20 percent 
reduction in NOX emissions through an engine retrofit.\75\ 
This retrofit is relatively simple on engine platforms similar to those 
used for the Tier 1 compliant engines, but the slide-valve injectors 
may not be compatible with older engines. We request comment on the 
costs and other business impacts of retrofitting Category 3 marine 
engines built before 2000 to meet the Tier 1 NOX standard.
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    \75\ Henningsen, S., ``2007 Panel Discussion on Emission 
Reduction Solutions for Marine Vessels; Engine Technologies'' 
presentation by MAN B&W at the Clean Ships: Advanced Technology for 
Clean Air Conference, February 8, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0031.
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2. Water-Based Technologies
    NOX emissions from Category 3 marine engines can be 
reduced by introducing water into the combustion process in combination 
with appropriate in-cylinder controls. Water can be used in the 
combustion process to lower the maximum combustion temperature, and 
therefore lower NOX formation without a significant increase 
in fuel consumption. Water has a high heat capacity which allows it to 
absorb enough of the energy in the cylinder to reduce peak combustion 
temperatures. Data from engine manufacturers suggest that, depending on 
the amount of water and how it is introduced into the combustion 
chamber, a 30 to 80 percent reduction in NOX can be achieved 
from Category 3 marine engines.76 77 78

[[Page 69539]]

However, some increase in PM may result due to the lower combustion 
temperatures, depending on the water introduction strategy.\79\ We 
request comment on the potential NOX reductions achievable 
from water-based technologies and what the impact on other pollutants 
or fuel consumption may be.
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    \76\ Heim, K., ``Future Emission Legislation and Reduction 
Possibilities,'' presentation by Wartsila at the CIMAC Circle 2006, 
September 28, 2006, Docket ID EPA-HQ-OAR-2007-0121-0017.
    \77\ Aabo, K., Kjemtrup, N., ``Latest on Emission Control Water 
Emulsion and Exhaust Gas Re-Circulation,'' MAN B&W, CIMAC paper 
number 126, presented at International Council on Combustion Engines 
Congress, 2004, Docket ID EPA-HQ-OAR-2007-0121-0005.
    \78\ Hagstrm, U., ``Humid Air Motor (HAM) and Selective 
Catalytic Reduction (SCR) Viking Line,'' presented by Viking Line at 
Swedish Maritime Administration Conference on Emission Abatement 
Technology on Ships, May 24-26, 2005, Docket ID EPA-HQ-OAR-2007-
0121-0027.
    \79\ Koehler, H., ``Field Experience with Considerably Reduced 
NOX and Smoke Emissions,'' MAN B&W, 2004, Docket ID EPA-
HQ-OAR-2007-0121-0019.
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    Water may be introduced into the combustion process through 
emulsification with the fuel, direct injection into the combustion 
chamber, or saturating the intake air with water vapor. Water 
emulsification refers to mixing the fuel and water prior to injection. 
This strategy is limited by the instability of the water in the fuel, 
but can be improved by mixing the water into the fuel just prior to 
injection into the cylinder. More effective control can be achieved 
through the use of an independent injection nozzle in the cylinder for 
the water. Using a separate injector nozzle for water allows larger 
amounts of water to be added to the combustion process because the 
water is injected simultaneously with the fuel, and larger injection 
pumps and nozzles can be used for the water injection. In addition, the 
fuel injection timing and water flow rates can be better optimized at 
different engine speeds and loads. Even higher water-to-fuel ratios can 
be achieved through the use of combustion air humidification and steam 
injection. With combustion air humidification, a water nozzle is placed 
in the engine intake and an air heater is used to offset condensation. 
With steam injection, waste heat is used to vaporize water, which is 
then injected into the combustion chamber during the compression 
stroke.
    Depending on the targeted NOX emission reduction, the 
amount of water used can range from half as much as the fuel volume to 
more than three times as much. Fresh water is necessary for the water-
based NOX reduction techniques. Introducing saltwater into 
the engine could result in serious deterioration due to corrosion and 
fouling. For this reason, a ship using water strategies would need 
either to produce fresh water through the use of a desalination or 
distillation system or to store fresh water on-board. Often, waste heat 
in the exhaust is used to generate fresh water for on-board use. We 
request comment on the capabilities of marine vessels, especially 
ocean-going ships, to generate sufficient fresh water on-board to 
support the use of water-based NOX control technologies. For 
vessels making shorter trips, we request comment on the costs 
associated with storing fresh water on board and replenishing the water 
supply when at port. We also request comment on the hardware and 
operating costs associated with this emission control technology.
3. Exhaust Gas Recirculation
    Exhaust gas recirculation (EGR) is a strategy similar to water-
based NOX reduction approaches in that a non-combustible 
fluid (in this case exhaust gas) is added to the combustion process. 
The exhaust gas is inert and reduces peak combustion temperatures, 
where NOX is formed, by slowing reaction rates and absorbing 
some of the heat generated during combustion. One study concluded that 
EGR could be used to achieve similar NOX emission reductions 
as water emulsion.\80\ However, due to the risk of carbon deposits and 
deterioration due to sulfuric acid in the exhaust gas when high sulfur 
fuel is used, any exhaust gases recirculated to the cylinder intake 
would have to be cleaned before being routed back into the cylinder. 
One method of cleaning the exhaust would be to use a seawater 
scrubber.\81\ Another alternative is to use internal EGR where a 
portion of the exhaust gases is held in the cylinder after combustion 
based on the cylinder scavenging design.\82\
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    \80\ Aabo, K., Kjemtrup, N., ``Latest on Emission Control Water 
Emulsion and Exhaust Gas Re-Circulation,'' MAN B&W, CIMAC paper 
number 126, presented at International Council on Combustion Engines 
Congress, 2004, Docket ID EPA-HQ-OAR-2007-0121-0005.
    \81\ Henningsen, S., ``2007 Panel Discussion on Emission 
Reduction Solutions for Marine Vessels; Engine Technologies'' 
presentation by MAN B&W at the Clean Ships: Advanced Technology for 
Clean Air Conference, February 8, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0031.
    \82\ Weisser, G., ``Emission Reduction Solutions for Marine 
Vessels--Wartsila Perspective'' presentation by Wartsila at the 
Clean Ships: Advanced Technology for Clean Air Conference, February 
8, 2007, Docket ID EPA-HQ-OAR-2007-0121-0032.
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B. NOX Aftertreatment

    NOX emissions can be reduced substantially using 
selective catalytic reduction (SCR), which is a commonly-used 
technology reducing NOX emissions standards in diesel 
applications worldwide. Stationary power plants fueled with coal, 
diesel, and natural gas have used SCR for three decades as a means of 
controlling NOX emissions. European heavy-duty truck 
manufacturers are using this technology to meet Euro 5 emissions limits 
and several heavy-duty truck engine manufacturers have indicated that 
they will use SCR technology to meet stringent U.S. NOX 
limits beginning in 2010. Collaborative research and development 
activities between diesel engine manufacturers and SCR catalyst 
suppliers suggest that SCR is a mature, cost-effective solution for 
NOX reduction on diesel engines.
    SCR has also been demonstrated for use with marine diesel engines. 
More than 300 SCR systems have been installed on marine vessels, some 
of which have been in operation for more than 10 years and have 
accumulated 80,000 hours of operation.83 84 85 86 These 
systems are used in a wide range of ship types including ferries, 
supply ships, ro ros (roll-on roll-off), tankers, container ships, 
icebreakers, cargo ships, workboats, cruise ships, and foreign navy 
vessels for both propulsion and auxiliary engines. These SCR units are 
being used successfully on slow and medium speed Category 3 propulsion 
engines and on Category 2 propulsion and auxiliary engines. The fuel 
used on ships with SCR systems ranges from low sulfur distillate fuel 
to high sulfur residual fuel. SCR is capable of reducing NOX 
emissions in marine diesel exhaust by more than 90 percent and can have 
other benefits as well.87 88 89 Fuel consumption 
improvements may also be gained with the use of an SCR system. By 
relying on the SCR unit for NOX emissions control, the 
engine can be optimized for better fuel consumption, rather than for 
low NOX emissions. When an oxidation catalyst is used in 
conjunction with the SCR unit, significant reductions in HC, CO, and

[[Page 69540]]

PM may also be achieved. The SCR unit attenuates sound, so it may use 
the space on the vessel that would normally hold a large muffler 
generally referred to as an exhaust gas silencer. To the extent that 
SCR has been used in additional marine applications, we request further 
information on the emission reductions that have been achieved. We also 
request comment on the durability, packaging, and cost of these 
systems.
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    \83\ ``DEC SCR Convertor System,'' Muenters, May 1, 2006, Docket 
ID EPA-HQ-OAR-2007-0121-0013.
    \84\ Hagstr[ouml]m, U., ``Humid Air Motor (HAM) and Selective 
Catalytic Reduction (SCR),'' Viking Line, presented at Air Pollution 
from Ships, May 24-26, 2005, Docket ID EPA-HQ-OAR-2007-0121-0027.
    \85\ ``Reference List--SINOX[supreg] Systems,'' 
Argillon, December 2006, Docket ID EPA-HQ-OAR-2007-0121-0035.
    \86\ ``Reference List January 2005 Marine Applications,'' Hug 
Engineering, January 2005, Docket ID EPA-HQ-OAR-2007-0121-0036.
    \87\ Heim, K., ``Future Emission Legislation and Reduction 
Possibilities,'' W[auml]rtsil[auml], presented at CIMAC Circle 2006, 
September 28, 2006, Docket ID EPA-HQ-OAR-2007-0121-0017.
    \88\ Argillon, ``Exhaust Gas Aftertreatment Systems; SCR--The 
Most Effective Technology for NOX Reduction,'' presented 
at Motor Ship Marine Propulsion Conference, May 7-8, 2003, Docket ID 
EPA-HQ-OAR-2007-0121-0010.
    \89\ Holmstr[ouml]m, Per, ``Selective Catalytic Reduction,'' 
presentation by Munters at Clean Ships: Advanced Technology for 
Clean Air, February 7-9, 2007, Docket ID EPA-HQ-OAR-2007-0121-0013.
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    An SCR catalyst reduces nitrogen oxides to elemental nitrogen 
(N2) and water by using a small amount of ammonia 
(NH3) as the reducing agent. The most-common method for 
supplying ammonia to the SCR catalyst is to inject an aqueous urea-
water solution into the exhaust stream. In the presence of high-
temperature exhaust gases (>200 [deg]C), the urea in the injected 
solution hydrolyzes to form NH3. The NH3 is 
stored on the surface of the SCR catalyst where it is used to complete 
the NOX reduction reaction. In theory, it is possible to 
achieve 100 percent NOX conversion if the exhaust 
temperature is high enough and the catalyst is large enough. Low 
temperature NOX conversion efficiency can be improved 
through use of an oxidation catalyst upstream of the SCR catalyst to 
promote the conversion of NO to NO2. Because the reduction 
of NOX can be rate limited by NO reductions, converting some 
of the NO to NO2 also allows manufacturers to use a smaller 
reactor.
    Manufacturers report minimum exhaust temperatures for SCR units to 
be in the range of 250 to 300 [deg]C, depending on the catalyst system 
design and fuel sulfur level.90 91 92 Below this 
temperature, the vanadium-oxide catalyst in the SCR unit would not be 
hot enough to efficiently reduce NOX. With very low sulfur 
fuels, a highly reactive oxidation catalyst can be used upstream of the 
SCR reactor to convert NO to NO2. NO2 reacts in 
the SCR catalyst at lower temperatures than NO; therefore, the 
oxidation catalyst lowers the exhaust temperature at which the SCR unit 
is effective. However, as the sulfur concentration increases, a less 
reactive oxidation catalyst must be used to prevent excessive formation 
of sulfates and poisoning of the oxidation catalyst. When operating on 
marine distillate fuel with a sulfur level of 1,000 ppm, the minimum 
exhaust temperature for effective reductions through a current SCR 
system would be on the order of 270 [deg]C. On typical heavy fuel oils, 
which have sulfur concentrations on the order of 2.5 percent, the 
exhaust temperature would need to be about 300[deg]C due to high sulfur 
concentrations. We request comment on the relationship between SCR 
operating temperatures and the quality of the fuel used.
---------------------------------------------------------------------------

    \90\ Rasmussen, K., Ellegasrd, L., Hanafusa, M., Shimada, K., 
``Large Scale SCR Application on Diesel Power Plant,'' CIMAC paper 
number 179, presented at International Council on Combustion Engines 
Congress, 2004, Docket ID EPA-HQ-OAR-2007-0121-0007.
    \91\ ``Munters SCR ConverterTM System,'' downloaded 
from www.munters.com, November 21, 2006, Docket ID EPA-HQ-OAR-2007-
0121-0023.
    \92\ Argillon, ``Exhaust Gas Aftertreatment Systems; SCR--The 
Most Effective Technology for NOX Reduction,'' presented 
at Motor Ship Marine Propulsion Conference, May 7-8, 2003, Docket ID 
EPA-HQ-OAR-2007-0121-0010.
---------------------------------------------------------------------------

    SCR can be operated in exhaust streams at or above 500 [deg]C 
before heat-related degradation of the catalyst becomes significant. 
This maximum exhaust temperature is sufficient for use with Category 3 
marine engines. Exhaust valve temperatures are generally maintained 
below 450[deg]C to minimize high temperature corrosion and fouling 
caused by vanadium and sodium present in residual fuel.
    Modern SCR systems should be able to achieve very high 
NOX conversion for all operation covered by the E3 test 
cycle, which includes power levels from 25 to 100 percent. A properly 
designed system can generally maintain exhaust temperatures high enough 
at these power levels to ensure proper functioning of the improved SCR 
catalysts. However, exhaust temperatures at lower power levels on 
current vessels may be below the minimum temperature threshold for SCR 
systems, especially when operated on high sulfur fuels. We believe that 
it is important that NOX emission control is achieved even 
at low power due to the concern that much of the engine operation that 
occurs near the shore may be at less than 25 percent power. As 
described in Section VII.A.2, we are considering the need for changes 
to the test cycle or other supplemental requirements to account for the 
fact that the current test cycle does not include any operation below 
25 percent power. We request comment on engine power levels, and 
corresponding exhaust temperature profiles, when maneuvering, operating 
at low speeds, or during other operation near shore.
    We believe there are several approaches that can be used to ensure 
that the exhaust temperature during low power operation is sufficiently 
high for the SCR unit to function properly. By positioning the SCR 
system ahead of the turbocharger, the heat to the SCR system can be 
maximized. This approach was used with vessels equipped with slow-speed 
engines that operated at low loads near the coast.\93\ Exhaust 
temperatures could be increased by adjusting engine parameters, such as 
reduced charge air cooling and modified injection timing. In one case, 
SCR was used on a short passage car ferry which originally had exhaust 
temperatures below 200 [deg]C when the engine was operated at low 
load.\94\ When the SCR unit was installed, controls were placed on the 
intercooler in the air intake system. By reducing the cooling on the 
intake air, the exhaust temperature was increased to be within the 
operating range of the SCR unit, even during low power operation. In a 
ship using multiple propulsion engines, one or more engines could be 
shut down such that the remaining engine or engines are operating at 
higher power. Another approach to increase the exhaust temperature 
could be to use burner systems during low power operation. If 
commenters have additional information on using SCR at low power 
operation, we request that this information be submitted for our 
consideration as we continue developing proposed standards for Category 
3 marine engines.
---------------------------------------------------------------------------

    \93\ MAN B&W, ``Emission Control Two-Stroke Low-Speed Diesel 
Engines,'' December 1996, Docket ID EPA-HQ-OAR-2007-0121-0020.
    \94\ ``NOX Emissions from M/V Hamlet,'' Data provided 
to W. Charmley, U.S. EPA. by P. Holmstr[ouml]m, DEC Marine, February 
5, 2007, Docket ID EPA-HQ-OAR-2007-0121-0015.
---------------------------------------------------------------------------

    SCR grade urea is a widely used industrial chemical around the 
world. Although an infrastructure for widespread transportation, 
storage, and dispensing of SCR-grade urea does not currently exist in 
most places, we believe that it would develop as needed based on market 
forces. Concerning urea production capacity, the U.S. has more-than-
sufficient capacity to meet the additional needs of the marine engines. 
Currently, the U.S. consumes 14.7 million tons of ammonia resources per 
year, and relies on imports for 41 percent of that total (of which, 
urea is the principal derivative). In 2005, domestic ammonia producers 
operated their plants at 66 percent of rated capacity, resulting in 4.5 
million tons of reserve production capacity.\95\ Thus we do not project 
that urea cost or supply will be an issue. As an alternative, one study 
looked at using hydrocarbons distilled from the marine fuel oil as a 
reductant for an SCR unit.\96\ We request

[[Page 69541]]

comment on any issues related using urea, or any other reductant, on 
ships such as costs, on-board storage requirements, and supply 
infrastructure.
---------------------------------------------------------------------------

    \95\ U.S. Department of the Interior, ``Mineral Commodity 
Summaries 2006,'' page 118, U.S. Geological Survey, January 13, 
2006, Docket ID EPA-HQ-OAR-2007-0121-0022.
    \96\ Tokunaga, Y., Kiyotaki, G., ``Development of NOX 
Reduction System for Marine Diesel Engines by SCR using Liquid 
Hydrocarbon Distilled from Fuel Oil as Reductant,'' CIMAC paper 
number 63, presented at International Council on Combustion Engines 
Congress, 2004, Docket ID EPA-HQ-OAR-2007-0121-0002.
---------------------------------------------------------------------------

C. PM and SOX Control

    As discussed above, we are considering PM and SOX 
emission control approaches based on both fuel sulfur limits and 
performance based requirements. This section discusses traditional in-
cylinder emission controls, fuel quality, and exhaust gas scrubbing 
technology.
1. In-Cylinder Controls
    For typical diesel engines operating on distillate fuel, 
particulate matter formation is primarily the result of incomplete 
combustion of the fuel and lube oil. The traditional in-cylinder 
technologies discussed above for NOX emission control can be 
optimized for PM control while simultaneously reducing NOX 
emissions. If aftertreatment, such as SCR, is used to control 
NOX, then the in-cylinder technologies can be used primarily 
for PM reductions. However, the PM reduction through in-cylinder 
technologies is limited for engines operating on high-sulfur fuel 
because the majority of the PM emissions in this case are due to 
compounds in the fuel rather than due to incomplete combustion, as 
discussed below.
2. Fuel Quality
    The majority of Category 3 engines are designed to run on residual 
fuel which has the highest viscosity and lowest price of the petroleum 
fuel grades. Residual fuels are known by several names including heavy 
fuel oil (HFO), bunker C fuel, and marine fuel oil. This fuel is made 
from the very end products of the oil refining process, formulated from 
residues remaining in the primary distilling stages of the refining 
process. It has high content of ash, metals, nitrogen, and sulfur that 
increase emissions of exhaust PM pollutants. Typical residual fuel 
contains about 2.7 percent sulfur, but may have a sulfur content as 
high as 4.5 percent.
    When a diesel engine is operating on very low sulfur distillate 
fuel, 80 to 90 percent of the PM in the exhaust is unburned 
hydrocarbons from the fuel and lubricating oil and carbon soot. When 
residual fuel is used, only about 25 to 35 percent of the PM from the 
engine is made up of unburned hydrocarbon compounds.97 98 99 
In this case, the majority of the PM from the engine is made up of 
sulfur, metal, and ash components originating from the fuel itself. On 
a mass basis, the vast majority of this fuel-based PM is due to the 
sulfur which oxidizes in the combustion process and associates with 
water to form an aqueous solution of sulfuric acid, known as sulfate 
PM. Data suggest that about two percent of the sulfur in the fuel is 
converted directly to sulfate PM.100 101 The rest of the 
sulfur in the fuel forms SOX emissions. These SOX 
emissions lead to indirect PM formation in the atmosphere.
---------------------------------------------------------------------------

    \97\ Paro, D., ``Effective, Evolving, and Envisaged Emission 
Control Technologies for Marine Propulsion Engines,'' presentation 
from Wartsila to EPA on September 6, 2001, Docket ID EPA-HQ-OAR-
2007-0121-0028.
    \98\ Koehler, H., ``Field Experience with Considerably Reduced 
NOX and Smoke Emissions,'' MAN B&W, 2004, Docket ID EPA-
HQ-OAR-2007-0121-0019.
    \99\ Heim, K., ``Future Emission Legislation and Reduction 
Possibilities,'' presentation by Wartsila at the CIMAC Circle 2006, 
September 28, 2006, Docket ID EPA-HQ-OAR-2007-0121-0017.
    \100\ ``Emission Factors for Compression Ignition Nonroad 
Engines Operated on No. 2 Highway and Nonroad Diesel Fuel,'' U.S. 
EPA, EPA420-R-98-001, March 1998, Docket ID EPA-HQ-OAR-2007-0121-
0025.
    \101\ Lyyranen, J., Jokiniemi, J., Kauppinen, E., Joutsensaari, 
J., ``Aerosol Characterization in Medium-Speed Diesel Engines 
Operating with Heavy Fuel Oils,'' Aerosol Science Vol. 30, No. 6, 
pp. 771-784, 1999, Docket ID EPA-HQ-OAR-2007-0121-0009.
---------------------------------------------------------------------------

    We believe that substantial PM and SOX reductions could 
be achieved through the use of lower sulfur fuel. Using a residual fuel 
with a lower sulfur content would reduce the fraction of PM from 
sulfate formation. One study showed a decrease of PM emissions from 
more than 1.0 g/kW-hr on 2.4 percent sulfur fuel to less than 0.5 g/kW-
hr with 0.8 percent sulfur fuel for a medium-speed generator engine on 
a ship.\102\ Using distillate fuel would likely have further reduced 
sulfur-based emissions and PM emissions from ash and metals. Another 
study compared PM emissions from a large 2-stroke marine engine on both 
low sulfur residual fuel oil and marine distillate oil and reported 
about a 70 percent reduction in PM.\103\ The simpler molecular 
structure of distillate fuel may result in more complete combustion and 
reduced levels of carbonaceous PM (soot and heavy hydrocarbons). 
Because SOX emissions are directly related to the 
concentration of sulfur in the fuel, a given percent reduction in 
sulfur in the fuel would be expected to result in about the same 
percent reduction in SOX emissions from the engine. We 
request comment on the potential PM and SOX emission 
reductions that could be achieved through the use of lower sulfur 
residual fuel or through the use of distillate fuel in Category 3 
marine engines.
---------------------------------------------------------------------------

    \102\ Maeda, K., Takasaki, K., Masuda, K., Tsuda, M., Yasunari, 
M., ``Measurement of PM Emission from Marine Diesel Engines,'' CIMAC 
paper number 107 presented at International Council on Combustion 
Engines Congress, 2004, Docket ID EPA-HQ-OAR-2007-0121-0004.
    \103\ Kasper, A., Aufdenblatten, S., Forss, A., Mohr, M., 
Burtscher, H., ``Particulate Emissions from a Low-Speed Marine 
Diesel Engine,'' Aerosol Science and Technology, 41:24-32, 2007.
---------------------------------------------------------------------------

    In general, engines that are designed to operate on residual fuel 
are capable of operating on distillate fuel. For example, if the engine 
is to be shut down for maintenance, distillate fuel is typically used 
to flush out the fuel system. There are some issues that would need to 
be addressed for operating engines on distillate fuel that were 
designed primarily for use on residual fuel. Switching to distillate 
fuel requires 20 to 60 minutes, depending on how slowly the operator 
wants to cool the fuel temperatures. According to engine manufacturers, 
switching from a heated residual fuel to an unheated distillate too 
quickly could cause damage to fuel pumps. These fuel pumps would need 
to be designed to operate on both fuels if a fuel-switching strategy 
were employed. Separate fuel tanks would be needed for distillate fuel 
with sufficient capacity for potentially extended operation on this 
fuel. It is common for ships to have several fuel tanks today to 
accommodate the variety in different grades of residual fuel which may 
be incompatible with each other and, therefore, require segregation. 
Also, different lubricating oil is used with each fuel type. We believe 
that properly designed ships would be able to operate on distillate 
fuel either under a fuel-switching strategy or for extended use. We 
request comment on the practical implications of operating ships on 
either lower sulfur residual or distillate fuel for extended use.
    Fuel quality may also affect NOX emissions. Residual 
fuels have nitrogen bound into the fuel at a concentration on the order 
of 0.3 to 0.4 weight percent. In contrast, marine distillate fuel has 
about a 0.02 to 0.06 weight percent concentration of nitrogen in the 
fuel. Approximately half of nitrogen in the fuel will oxidize to form 
NOX in a marine diesel engine.\104\ In addition, the 
ignition quality of the fuel may be worse for residual fuel than for 
distillate fuel which can affect NOX emissions. These 
effects are reflected in the MARPOL NOX technical code which 
allows an

[[Page 69542]]

upward adjustment of 10 percent for NOX, under certain 
circumstances, when the engine is tested on residual fuel. We request 
comment on the effect of using residual fuel on NOX 
emissions, both due to nitrogen in the fuel and any impacts of fuel 
quality on ignition-delay or other combustion characteristics.
---------------------------------------------------------------------------

    \104\ Takasaki, K., Tayama, K., Tanaka, H., Baba, S., Tajima, 
H., Strom, A., ``NOX Emission from Bunker Fuel 
Combustion,'' CIMAC paper number 87, presented at International 
Council on Combustion Engines Congress, 2004, Docket ID EPA-HQ-OAR-
2007-0121-0003.
---------------------------------------------------------------------------

    There are several types of processes refineries use to remove 
sulfur from fuels. Traditional sulfur removal technologies include 
installing a hydrocracker upstream, or a hydrotreater upstream or 
downstream, of the fluidized catalytic cracker (FCC) unit. Due to high 
refinery production costs, it is not likely that much new volume of 
residual fuel will be desulfurized to create 1,000 ppm heavy fuel oil. 
It is more likely that additional distillate fuel may be produced by 
cracking existing residual fuels or that blends of high and low sulfur 
fuels will be used. Some existing low sulfur residual fuel is already 
produced, though the volume is probably insufficient to fully meet fuel 
volume requirements for both ships and land-based applications subject 
to local sulfur emission requirements. We request comment on the 
availability of low sulfur marine fuels.
3. Exhaust Gas Scrubbers
    Another approach to reduce PM and SOX emissions is to 
use seawater scrubbers. Seawater scrubbers are an aftertreatment 
technology that uses the seawater's ability to absorb SO2. 
In the scrubber, the exhaust gases are brought into contact with 
seawater. The SO2 in the exhaust reacts with oxygen to 
produce sulfur trioxide that subsequently reacts with water to yield 
sulfuric acid. The sulfuric acid in the water then reacts with 
carbonate (and other salts) in the seawater to form sulfates which may 
be removed from the exhaust. The carbonate also directionally 
neutralizes the pH of the sulfuric acid.
    A scrubber system does not necessarily need to use sea water. An 
alternative approach is to circulate fresh water through the scrubber 
system. In this design, the pH of the wash water is monitored and 
additional caustic solution is added as necessary. If the pH becomes 
too low, the water will not absorb any further sulfur. During typical 
operation, a small amount of wash water is bled out of the system and 
fresh water is added to maintain volume. This prevents excessive build-
up of contaminants in the wash water.
    Water may be sprayed into the exhaust stream, or the exhaust gasses 
may be routed through a water bath. As the cooled exhaust gas rises out 
the stack, demisters are used to separate water droplets that may be 
entrained in the exhaust. The cleaned exhaust passes out of the 
scrubber through the top while the water, containing sulfates, is 
drained out through the bottom. Recent demonstration projects have 
shown scrubbers are capable of reducing SOX emissions on the 
order of 95 percent.\105\ Today, exhaust gas silencers are used on 
ships to muffle noise from the exhaust. Seawater scrubbers would act as 
mufflers making the exhaust gas silencers unnecessary. New seawater 
scrubber designs are not much larger than exhaust gas silencers already 
used on ships, and could be packaged in the space formerly used by an 
exhaust gas silencer.\106\ We request comment on further experience 
with seawater scrubbers and on the practical issues related to 
installing scrubbers on ships, including space constraints and costs.
---------------------------------------------------------------------------

    \105\ Skawinski, C., ``Seawater Scrubbing Advantage,'' 
Presentation by Marine Exhaust Solutions at the Conference for 
Emission Abatement Technology on Ships held by the Swedish Maritime 
Administration, May 24-26, 2005, Docket ID EPA-HQ-OAR-2007-0121-
0021.
    \106\ ``Krystallon Seawater Scrubber,'' downloaded from http://www.krystallon.com on February 14, 2007, Docket ID EPA-HQ-OAR-2007-
0121-0018.
---------------------------------------------------------------------------

    Exhaust gas scrubbers can achieve reductions in particulate matter 
as well. By removing sulfur from the exhaust, the scrubber removes most 
of the direct sulfate PM. As discussed above, sulfates are a large 
portion of the PM from ships operating on high sulfur fuels. By 
reducing the SOX emissions, the scrubber will also control 
much of the secondary PM formed in the atmosphere from SOX 
emissions.
    Simply mixing alkaline water in the exhaust does not necessarily 
remove much of the carbonaceous PM, ash, or metals in the exhaust. 
While SO2 associates with the wash water, particles can only 
be washed out of the exhaust through direct contact with the water. In 
simple scrubber designs, much of the mass of particles can hide in gas 
bubbles and escape out the exhaust. Manufacturers have been improving 
their scrubber designs to address carbonaceous soot and other fine 
particles. Finer water sprays, longer mixing times, and turbulent 
action would be expected to directionally reduce PM emissions through 
contact impactions. One scrubber design uses an electric charge on the 
water to attract particles in the exhaust to the water. Two chambers 
are used so that both a positive and a negative charge can be used to 
attract both negatively-charged and positively-charged particles. The 
manufacturer reports an efficiency of more than 99 percent for the 
removal for particulate matter and condensable organics in diesel 
exhaust.\107\ Although exhaust gas scrubbers are only used in a few 
demonstration vessels today, this technology is widely used in land-
based applications. We request comment on how scrubber design impacts 
the amount of PM that is removed from the exhaust.
---------------------------------------------------------------------------

    \107\ ``Cloud Chamber Scrubber Performance Results for Diesel 
Exhaust,'' Tri-Mer Corporation, April 14, 2005, Docket ID EPA-HQ-
OAR-2007-0121-0026.
---------------------------------------------------------------------------

    It may be possible to achieve NOX reductions through the 
use of seawater scrubbers. In a typical scrubber, the water-soluble 
fraction of NOX (NO2) can combine with the water 
to form nitrates which are scrubbed out of the exhaust. However, 
because NO2 makes up only a small fraction of total 
NOX, this results in less than a 10 percent reduction in 
NOX emissions exhausted to atmosphere.\108\ Seawater 
electrolysis systems have been developed which increase the adsorption 
rate of NOX in the water by oxidizing NO to NO2, 
which is water-soluble.\109\ One study used electrolysis in an 
experimental scrubbing system to remove 90 percent of the NO and nearly 
all of the NO2 in the feed gas.\110\ We request comment on 
the feasibility of achieving significant NOX reductions from 
Category 3 marine engines through the use of seawater scrubbers. We 
also request comment on the impact of this technology on nitrate 
loading and eutrophication of surrounding waters.
---------------------------------------------------------------------------

    \108\ Skawinski, C., ``Seawater Scrubbing Advantage,'' 
Presentation by Marine Exhaust Solutions at the Conference for 
Emission Abatement Technology on Ships held by the Swedish Maritime 
Administration, May 24-26, 2005, Docket ID EPA-HQ-OAR-2007-0121-
0021.
    \109\ An, S., Nishida, O., ``Marine Air Pollution Control System 
Development Applying Seawater and Electrolyte,'' SAE Paper 2002-01-
2295, July 2002, Docket ID EPA-HQ-OAR-2007-0121-0024.
    \110\ Houng-Soo, K., ``Development of Diesel Engine Emission 
Control System on NOX and SOX by Seawater 
Electrolysis,'' CIMAC paper number 25 presented at International 
Council on Combustion Engines Congress, 2004, Docket ID EPA-HQ-OAR-
2007-0121-0001.
---------------------------------------------------------------------------

    Water-soluble components of the exhaust gas such as SO2, 
SO3, and NO2 form sulfates and nitrates that are 
dumped overboard in the discharge water. Scrubber wash water also 
includes suspended solids, heavy metals, hydrocarbons and PAHs. Before 
the scrubber water is discharged, it may be processed to remove solid 
particles through several approaches. Heavier particles may be trapped 
in a settling or sludge tank for disposal. The removal process may 
include cyclone technology similar to that used to separate water from 
residual fuel prior to delivery to the engine. However, depending on

[[Page 69543]]

particle size distribution and particle density, settling tanks and 
hydrodynamic separation may not effectively remove all suspended 
solids. Other approaches include filtration and flocculation 
techniques. Flocculation, which is used in many waste water treatment 
plants, refers to adding a chemical agent to the water that will cause 
the fine particles to aggregate so that they may be filtered out. 
Sludge separated from the scrubber water would be stored on board until 
it is disposed of at proper facilities. We request comment on 
appropriate waste discharge limits for scrubber water and how these 
limits should be defined. We are concerned that if limits are based on 
the concentration of the pollutants in the water, then the standards 
could be met simply by diluting the effluent before it is discharged. 
Although diluting the discharge water may have some local benefits near 
the vessel, it would not change the total pollutant load on a given 
body of water. We request comment on basing limits for waste water 
pollutants on engine load, similar to exhaust emission standards.

VII. Certification and Compliance

    In general, we expect to retain the certification and compliance 
provisions finalized with the Tier 1 standards. These include testing, 
durability, labeling, maintenance, prohibited acts, etc. However, we 
believe additional testing and compliance provisions will be necessary 
for new standards requiring more advanced technology and more 
challenging calibrations. These changes, as well as other modifications 
to our certification and compliance provisions, are discussed below.

A. Testing

1. PM Sampling
    In the past, there has been some concern regarding the use of older 
PM measurement procedures with high sulfur residual fuels. The primary 
issue of concern was variability of the PM measurement, which was 
strongly influenced by the amount of water bound to sulfur. However, we 
believe improvements in PM measurement procedures, such as those 
specified in 40 CFR 1065, have addressed these issues of measurement 
variability. The U.S. government recently submitted proposed procedures 
for PM measurement to IMO.\111\ We request comment on these procedures 
for accurately measuring PM emissions from Category 3 marine engines 
operating on residual fuel.
---------------------------------------------------------------------------

    \111\ Measurement Method for Particulate Matter Emitted from 
Marine Engines, submitted by the United States. BLG-WGAP 2, October 
2007. Intersessional Meeting of the BLG Working Group on Air 
Pollution, 2nd Session.
---------------------------------------------------------------------------

2. Low Power Operation
    We are concerned about emission control performance when the engine 
is operated at low power. Category 3 engines operate at relatively low 
power levels when they are operating in port areas. Ship pilots 
generally operate engines at reduced power for several miles to 
approach a port, with even lower power levels very close to shore. The 
ISO E3 and E2 test cycles are used for emission testing of propulsion 
marine engines. These test cycles are heavily weighted towards high 
power. Therefore, it is very possible that manufacturers could meet the 
cycle-weighted average emission standards without significantly 
reducing emissions at low-power modes. Because low power operation is 
more prevalent for propulsion engines when they operate close to 
commercial ports, it is important that the emission control strategy be 
effective at low power operation to maximize on-shore emission 
benefits. This issue would generally not apply to vessels that rely on 
multiple engines providing electric-drive propulsion, because these 
engines can be shut down as needed to maintain the desired engine 
loading and therefore may not operate at low power settings. We request 
comment on the need for addressing emissions at low power operation and 
whether and how the test procedure should be changed to accommodate 
this operation. See section VI.B for additional discussion of low power 
NOX emissions for engines equipped with exhaust 
aftertreatment.
3. Test Fuel
    Appropriate test procedures need to represent in-use operating 
conditions as much as possible, including specification of test fuels 
consistent with the fuels that compliant engines will use over their 
lifetimes. For the Tier 1 standards, we allow engine testing using 
distillate fuel, even though vessels with Category 3 marine engines 
primarily use the significantly less expensive residual fuel. This 
provision is consistent with the specifications of the NOX 
Technical Code. Also, most manufacturers have test facilities designed 
to test engines using distillate fuel. Distillate fuel is easier to 
test with because it does not need to be heated to remain a liquid and 
manufacturers have indicated that it is difficult to obtain local 
permits for testing with residual fuel. However, we believe it is 
important to specify a test fuel that is consistent with the in-use 
fuel with which engines will operate in service. This is especially 
true for PM measurements. We request comment on the appropriate test 
fuel for emission testing and if this fuel should be representative on 
the fuel on which a specific engine is designed to operate.
    For any NOX measurements from engines operating on 
residual fuel we recognize that there may be emission-related effects 
due to fuel quality, specifically fuel-bound nitrogen. If the standards 
were based on distillate fuel, we would consider a NOX 
correction factor to account for the impact of fuel quality when 
testing on residual fuel. This correction would be useful because of 
the high levels of nitrogen contained in residual fuel. Such a 
correction factor would likely involve measuring fuel-bound nitrogen 
and correcting measured values to what would occur with a nitrogen 
concentration of 0.4 weight percent. This corrected value would be used 
to determine whether the engine meets emission standards or not. We 
request comment on the need for corrections and, if so, how the 
appropriate corrections would be developed.

B. On-Off Technologies

    One of the features of the emission control technologies that could 
be used to achieve significant NOX and PM reductions from C3 
engines is that they are not integral to the engine and the engine can 
be operated without them. Aftertreatment systems such as SCR or 
emission scrubbing, or the use of lower sulfur fuel, require a positive 
action on the part of the ship owner to make sure the emission control 
system is in operation or that the appropriate fuel is used. These 
types of technologies are often called ``on-off'' technologies.
    The increased operating costs of such controls associated with urea 
or other catalysts or with distillate usage suggest that it may be 
reasonable to allow these systems to be turned off while a ship is 
operated on the open ocean, far away from sensitive areas that are 
affected by ship emissions. In other words, EPA could elect to set 
geographically-based NOX and PM standards, with one limit 
that would apply when ships are operated within a specified distance 
from U.S. coasts, and another that would apply when ships are operated 
outside those limits.
    If EPA were to adopt such an approach, we would need to determine 
the areas in which ships would have to comply with the standards. We 
are currently exploring this issue through the air quality modeling for 
our proposed standards. There are other

[[Page 69544]]

issues associated with such an approach, including: The technological 
feasibility of by-pass systems and their impacts on the emission 
control systems when they are not in use; the level of the standard 
that would apply when the system is turned off; and how compliance 
would be demonstrated. There may also be additional certification 
requirements for ships equipped with such systems.
    We request comment on all aspects of this alternative, especially 
with regard to how such systems could be designed to ensure no loss of 
emission reductions.

C. Parameter Adjustment

    Given the broad range of ignition properties for in-use residual 
fuels, we expect that our in-use adjustment allowance for Category 3 
engines would result in a broad range of adjustment. We are therefore 
considering a requirement for operators to perform a simple field 
measurement test to confirm emissions after parameter adjustments or 
maintenance operations, using onboard emission measurement systems with 
electronic-logging equipment. We expect this issue will be equally 
important for more advanced engines that rely on water injection or 
aftertreatment for emission reductions. Onboard verification systems 
could add significant assurance that engines have properly operating 
emission controls.
    We envision a simpler measurement system than the type specified in 
Chapter 6 of the NOX Technical Code. As we described in the 
2003 final rule, we believe that onboard emission equipment that is 
relatively inexpensive and easy to use could verify that an engine is 
properly adjusted and is operating within the engine manufacturer's 
specifications. Note that Annex VI includes specifications allowing 
operators to choose to verify emissions through onboard testing, which 
suggests that Annex VI also envisioned that onboard measurement systems 
could be of value to operators. We request comment on requiring onboard 
verification systems on ships with Category 3 marine engines and on a 
description of such a system.

D. Certification of Existing Engines

    While we normally require certification only for newly built 
engines, we are considering emission standards that would apply to 
remanufactured engines in the existing fleet. This leads to questions 
about how one would certify the modified engines. We are considering 
adoption of one or more of the following simplified certification 
procedures for in-use engines:
     Basing certification for any engine on a pre-existing 
certificate if the engine is modified to be the same as a later engine 
that is already certified to the Tier 1 NOX standard.
     Testing in-use engines using portable emission measurement 
equipment, with appropriate consideration for any necessary deviations 
in the engine test cycle.
     Broadening the engine family concept for in-use engines to 
reduce the amount of testing necessary to certify a range of engines. 
This would require the same or similar hardware and calibration 
requirements to ensure that a single test engine can properly represent 
all the engines in the broader engine family.
     Developing alternatives to the NOX Technical 
File \112\ to simplify the certification burdens for existing vessels 
while ensuring that the modified engines and emission components may be 
appropriately surveyed and inspected.
---------------------------------------------------------------------------

    \112\ The NOX Technical File, required pursuant to 
Section 2.4 of the Technical Code on Control of Emissions of 
Nitrogen Oxides from Marine Diesel Engines, is a record containing 
details of engine parameters, including components and settings, 
which may influence the NOX emissions of the engine. The 
NOX Technical File also contains a description of onboard 
NOX verification procedures required for engine surveys. 
The NOX Technical File is developed by the engine 
manufacturer and must be approved by the authority issuing the 
engine certificate.
---------------------------------------------------------------------------

    We request comment on the best approach for ensuring compliance 
from existing engines. We also request comment on the simplified 
certification procedures listed above.

E. Other Compliance Issues

    We intend to apply the same exemptions to any new tier of Category 
3 marine diesel engine standards as currently apply under our Tier 1 
program. These exemptions, including the national security exemption, 
are set out in 40 CFR part 94, subpart J. We will also consider whether 
to include engines on foreign vessels in the program and whether we 
should also adopt standards for non-diesel engines such as gas turbine 
engines.
1. Engines on Foreign-Flagged Vessels
    Our current federal marine diesel engine standards do not apply to 
Category 1, 2, and 3 marine diesel engines installed on foreign-flagged 
vessels. In our 2003 Final Rule we acknowledged the contribution of 
engines on foreign-flagged vessels to U.S. air pollution but did not 
apply federal standards to foreign vessels (see 68 FR 9759, February 
28, 2003). This section summarizes the discussion from that 2003 Final 
Rule. We will continue to evaluate this issue as we develop the 
proposal for this rule.
    Section 213 of the Clean Air Act (42 U.S.C. 7547), authorizes 
regulation of ``new nonroad engine'' and ``new nonroad vehicle.'' 
However, Title II of the Clean Air Act does not define either ``new 
nonroad engine'' or ``new nonroad vehicle.'' Section 216 defines a 
``new motor vehicle engine'' to include an engine that has been 
``imported.'' EPA modeled the current regulatory definitions of ``new 
nonroad engine'' and ``new marine engine'' at 40 CFR 89.2 and 40 CFR 
94.2, respectively, after the statutory definitions of ``new motor 
vehicle engine'' and ``new motor vehicle.'' This was a reasonable 
exercise of the discretion provided to EPA by the Clean Air Act to 
interpret ``new nonroad engine'' or ``new nonroad vehicle.'' See Engine 
Manufacturers Assoc. v. EPA, 88 F.3d 1075, 1087 (DC Cir. 1996).
    The 1999 marine diesel engine rule did not apply to marine engines 
on foreign vessels. 40 CFR 94.1(b)(3). At that time, we concluded that 
engines installed on vessels flagged or registered in another country, 
that come into the United States temporarily, will not be subject to 
the emission standards. At that time, we believed that they were not 
considered imported under the U.S. customs law. As a result, we did not 
apply the standards adopted in that rule to those vessels (64 FR 73300, 
Dec. 29, 1999).
    The May 29, 2002 proposed rule for Category 3 marine diesel engines 
solicited comment on whether to exercise our discretion and modify the 
definition of a ``new marine engine'' to find that engine emission 
standards apply to foreign vessels that enter U.S. ports. However, in 
the February 28, 2003 final rule we determined that we did not need to 
determine whether we have the discretion to interpret ``new'' nonroad 
engine or vessel in such a manner.
    Foreign vessels were expected to comply with the MARPOL standards 
whether or not they were also subject to the equivalent Clean Air Act 
standards being adopted in that final rule. Consequently, we concluded 
that no significant emission reductions would be achieved by treating 
foreign vessels as ``new'' for purposes of the Tier 1 standards and 
there would be no significant loss in emission reductions by not 
including them. Therefore, we did not include foreign engines and 
vessels in our 2003 rulemaking and we did not revise the definition of 
``new marine engine'' at that time.

[[Page 69545]]

    In this rule we will evaluate under what circumstances we may and 
should define new nonroad engine and vessel to include foreign engines 
and vessels. As part of that evaluation, we will also assess the 
progress made by the international community toward the adoption of new 
more stringent international consensus standards that reflect advanced 
emission-control technologies.
2. Non-Diesel Engines
    Gas turbine engines are internal combustion engines that can 
operate using diesel fuel, residual fuel, or natural gas, but do not 
operate on a compression-ignition or other reciprocating engine cycle. 
Power is extracted from the combustion gas using a rotating turbine 
rather than reciprocating pistons. While gas turbine engines are used 
primarily in naval ships, a small number are being used in commercial 
ships. In addition, we have received indication that their use is 
growing in some applications such as cruise ships and liquid natural 
gas carriers. As we develop the proposal for this rule we will consider 
whether it is appropriate to regulate emissions from gas turbine 
engines and, if so, whether special provisions would be needed for 
testing and certifying turbine engines. For example, since turbine 
engines have no cylinders, we may need to address how to apply any 
regulatory provisions that depend on a specified value for per-cylinder 
displacement. We would welcome any emissions information that is 
available for turbine engines.
    Marine engines have been developed that can operate either on 
natural gas or a dual-fuel.\113\ In a dual-fuel application, a mixture 
of marine diesel oil and natural gas is used for the main engine that 
provides a means to comply with the low-sulfur fuel requirement. 
Natural gas engines are especially attractive to vessels that carry a 
cargo of liquefied petroleum gas due to the readily available fuel 
supply. Natural gas powered engines are similar to Category 3 marine 
engines operating on traditional diesel fuels, and we would consider 
including these engines in this rulemaking.
---------------------------------------------------------------------------

    \113\ Nylund, I., ``Status and Potentials of the Gas Engines,'' 
Wartsila, CIMAC paper number 163, presented at International Council 
on Combustion Engines Congress, 2004, Docket ID EPA-HQ-OAR-2007-
0121-0006.
---------------------------------------------------------------------------

    We request comment on fuels and engine types that we should 
consider in the scope of this rulemaking. We also request comments on 
test procedure or other compliance issues that would need to be 
considered for these fuels and engines.

VIII. Potential Regulatory Impacts

A. Emission Inventory

    The inventory contribution of Category 3 engines consists of two 
parts: emissions that occur in port areas and emissions that occur at 
various distances from the coast while vessels are underway. Although 
the issue of emissions transport is common to all of our air pollution 
control programs, these underway emissions suggest that Category 3 
emissions are different from emissions from other mobile sources and 
result in at least two implications for the analysis we will perform 
for our proposal. First, the definition of the inventory modeling 
domain becomes important. In the inventory analysis described below we 
use a distance of 200 nautical miles from shore (see Figure VIII-1 
below and associated text). This distance is reasonable based on both 
particle dynamics\114\ and results from air quality modeling for other 
programs which has shown that PM and NOX emissions can be 
transported significant distances.\115\ Second, it will be important to 
analyze the air quality impacts of these emissions at various distances 
to determine how offshore emissions affect air quality both along the 
coasts and inland. We will use the CMAQ model, modified to accommodate 
at-sea emissions, to track the impacts of underway emissions and 
estimate the air quality benefits of the proposal.
---------------------------------------------------------------------------

    \114\ U.S. EPA. Air Quality Criteria for Particulate Matter 
(October 2004). U.S. Environmental Protection Agency, Washington, 
DC, EPA 600/P-99/002aF-bF, 2004.
    \115\ U.S. EPA Technical Support Document for the Final Clean 
Air Interstate Rule Air Quality Modeling (March 2005) U.S. 
Environmental Protection Agency, Washington, DC.
---------------------------------------------------------------------------

    This section contains our updated inventory estimates for Category 
3 marine engines in the 200 nautical mile domain and a brief discussion 
of our inventory estimation methodology.
1. Estimated Inventory Contribution
    Category 3 marine engines contribute to the formation of ground 
level ozone and concentrations of fine particles in the ambient 
atmosphere. Based on our current emission inventory analysis of U.S. 
and foreign-flag vessels, we estimate that these engines contributed 
nearly 6 percent of mobile source NOX, over 10 percent of 
mobile source PM2.5, and about 40 percent of mobile source 
SO2 in 2001. We estimate that their contribution will 
increase to about 34 percent of mobile source NOX, 45 
percent of mobile source PM2.5, and 94 percent of mobile 
source SO2 by 2030 without further controls on these 
engines. Our current estimates for NOX, PM2.5, 
SO2 inventories are set out in Tables VIII-1 through VIII-3. 
The inventory projections for 2020 and 2030 include the impact of 
existing emission mobile source and stationary source control programs 
previously adopted by EPA (excluding the recently adopted MSAT 
regulations, signed on February 9, 2007 which will have an impact on 
future highway non-diesel PM2.5 levels).

                           Table VIII-1.--50-State Annual NOX Baseline Emission Levels for Mobile and Other Source Categories
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           2001 \a\                              2020                                2030
                                             -----------------------------------------------------------------------------------------------------------
                  Category                                   Percent                             Percent                             Percent
                                               Short tons   of mobile   Percent    Short tons   of mobile   Percent    Short tons   of mobile   Percent
                                                              source    of total                  source    of total                  source    of total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Commercial Marine (C3) \b\..................       745,224        5.7        3.3     1,368,420       22.8       11.3     2,023,974       33.7       16.7
Locomotive..................................     1,118,786        8.6        5.0       860,474       14.3        7.1       854,226       14.1        7.0
Recreational Marine Diesel..................        40,437        0.3        0.2        45,477        0.8        0.4        48,102        0.8        0.4
Commercial Marine (C1 & C2).................       834,025        6.4        3.7       676,154       11.3        5.6       680,025       11.3        5.6
Land-Based Nonroad Diesel...................     1,548,236       11.9        6.9       678,377       11.3        5.6       434,466        7.2        3.6
Small Nonroad SI............................       114,319        0.9        0.5       114,881        1.9        0.9       133,197        2.2        1.1
Recreational Marine SI......................        44,732        0.3        0.2        86,908        1.4        0.7        96,143        1.6        0.8
SI Recreational Vehicles....................         5,488        0.0        0.0        17,496        0.3        0.1        20,136        0.3        0.2
Large Nonroad SI (25hp).....................       321,098        2.5        1.4        46,319        0.8        0.4        46,253        0.8        0.4
Aircraft....................................        83,764        0.6        0.4       105,133        1.7        0.9       118,740        2.0        1.0
Total Off Highway...........................     4,856,109       37.5       21.8     3,999,640       66.6       33.0     4,455,262       74.2       36.8
Highway Diesel..............................     3,750,886       28.9       16.8       646,961       10.8        5.3       260,915        4.3        2.2
Highway non-diesel..........................     4,354,430       33.6       19.5     1,361,276       22.7       11.2     1,289,780       21.5       10.6
Total Highway...............................     8,105,316       62.5       36.3     2,008,237       33.4       16.6     1,550,695       25.8       12.8

[[Page 69546]]

 
Total Mobile Sources........................    12,961,425        100       58.1     6,007,877        100       49.6     6,005,957        100       49.6
Stationary Point & Area Sources.............     9,355,659  .........       41.9     6,111,866  .........       50.4     6,111,866  .........       50.4
                                             -----------------------------------------------------------------------------------------------------------
    Total Man-Made Sources..................    22,317,084  .........        100    12,119,743  .........        100    12,117,823  .........        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The locomotive, commercial marine (C1 & C2), and recreational marine diesel estimates are for calendar year 2002.
\b\ This category includes emissions from Category 3 (C3) propulsion engines and C2/3 auxiliary engines used on ocean-going vessels.


                          Table VIII-2.--50-State Annual PM2.5 Baseline Emission Levels for Mobile and Other Source Categories
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           2001 \a\                              2020                                2030
                                             -----------------------------------------------------------------------------------------------------------
                  Category                                   Percent                             Percent                             Percent
                                               Short tons   of mobile   Percent    Short tons   of mobile   Percent    Short tons   of mobile   Percent
                                                              source    of total                  source    of total                  source    of total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Commercial Marine (C3) \b\..................        54,667       10.9        2.2       110,993       33.6        5.2       166,161       45.4        7.6
Locomotive..................................        29,660        5.9        1.2        26,301        8.0        1.2        25,109        6.8        1.1
Recreational Marine Diesel..................         1,096        0.2        0.0         1,006        0.3        0.0         1,140        0.3        0.1
Commercial Marine (C1 & C2).................        28,730        5.7        1.2        22,236        6.7        1.0        23,760        6.5        1.1
Land-Based Nonroad Diesel...................       164,180       32.8        6.7        46,075       13.9        2.1        17,934        4.9        0.8
Small Nonroad SI............................        25,466        5.1        1.0        32,904       10.0        1.5        37,878       10.3        1.7
Recreational Marine SI......................        16,837        3.4        0.7         6,367        1.9        0.3         6,163        1.7        0.3
SI Recreational Vehicles....................        12,301        2.5        0.5        11,773        3.6        0.5         9,953        2.7        0.5
Large Nonroad SI (>25hp)....................         1,610        0.3        0.1         2,421        0.7        0.1         2,844        0.8        0.1
Aircraft....................................         5,664        1.1        0.2         7,044        2.1        0.3         8,569        2.3        0.4
Total Off Highway...........................       340,211       68.0       13.8       267,120       80.9       12.4       299,511       81.8       13.7
Highway Diesel..............................       109,952       22.0        4.5        15,800        4.8        0.7        10,072        2.7        0.5
Highway non-diesel..........................        50,277       10.0        2.0        47,354       14.3        2.2        56,734       15.5        2.6
Total Highway...............................       160,229       32.0        6.5        63,154       19.1        2.9        66,806       18.2        3.1
Total Mobile Sources........................       500,440        100       20.3       330,274        100       15.4       366,317        100       16.8
Stationary Point & Area Sources.............     1,963,264  .........       79.7     1,817,722  .........       84.6     1,817,722  .........       83.2
                                             -----------------------------------------------------------------------------------------------------------
    Total Man-Made Sources..................     2,463,704  .........        100     2,147,996  .........        100     2,184,039  .........        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The locomotive, commercial marine (C1 & C2), and recreational marine diesel estimates are for calendar year 2002.
\b\ This category includes emissions from Category 3 (C3) propulsion engines and C2/3 auxiliary engines used on ocean-going vessels.


                           Table VIII-3.--50-State Annual SO2 Baseline Emission Levels for Mobile and Other Source Categories
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           2001 \a\                              2020                                2030
                                             -----------------------------------------------------------------------------------------------------------
                  Category                                   Percent                             Percent                             Percent
                                               Short tons   of mobile   Percent    Short tons   of mobile   Percent    Short tons   of mobile   Percent
                                                              source    of total                  source    of total                  source    of total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Commercial Marine (C3) \b\..................       457,948       42.4        2.8       932,820       93.2       10.1     1,398,598       94.5       14.4
Locomotive..................................        76,727        7.1        0.5           400        0.0        0.0           468        0.0        0.0
Recreational Marine Diesel..................         5,145        0.5        0.0           162        0.0        0.0           192        0.0        0.0
Commercial Marine (C1 & C2).................        80,353        7.4        0.5         3,104        0.3        0.0         3,586        0.3        0.0
Land-Based Nonroad Diesel...................       167,615       15.5        1.0           999        0.1        0.0         1,078        0.1        0.0
Small Nonroad SI............................         6,710        0.6        0.0         8,797        0.9        0.1        10,196        0.7        0.1
Recreational Marine SI......................         2,739        0.3        0.0         2,963        0.3        0.0         3,142        0.2        0.0
SI Recreational Vehicles....................         1,241        0.1        0.0         2,643        0.3        0.0         2,784        0.2        0.0
Large Nonroad SI (25hp).....................           925        0.1        0.0           905        0.1        0.0         1,020        0.1        0.0
Aircraft....................................         7,890        0.7        0.0         9,907        1.0        0.1        11,137        0.8        0.1
Total Off Highway...........................       807,293       74.7        5.0       962,700       96.1       10.4     1,432,202       96.8       14.8
Highway Diesel..............................       103,632        9.6        0.6         3,443        0.3        0.0         4,453        0.3        0.0
Highway non-diesel..........................       169,125       15.7        1.0        35,195        3.5        0.4        42,709        2.9        0.4
Total Highway...............................       272,757       25.3        1.7        38,638        3.9        0.4        47,162        3.2        0.5
Total Mobile Sources........................     1,080,050        100        6.7     1,001,338        100       10.9     1,479,364        100       15.3
Stationary Point & Area Sources.............    15,057,420  .........       93.3     8,215,016  .........       89.1     8,215,016  .........       84.7
                                             -----------------------------------------------------------------------------------------------------------
    Total Man-Made Sources..................    16,137,470  .........        100     9,216,354  .........        100     9,694,380  .........        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The locomotive, commercial marine (C1 & C2), and recreational marine diesel estimates are for calendar year 2002.
\b\ This category includes emissions from Category 3 (C3) propulsion engines and C2/3 auxiliary engines used on ocean-going vessels.


[[Page 69547]]

    The United States is actively engaged in international trade and is 
frequently visited by ocean-going marine vessels. As shown in Figure 
II-1, the ports which accommodate these vessels are located along the 
entire coastline of the United States. Commercial marine vessels, 
powered by Category 3 marine engines, contribute significantly to the 
emissions inventory for many U.S. ports. This is illustrated in Table 
VIII-4 which presents the mobile source inventory contributions of 
these vessels for several ports. The ports in this table were selected 
to present a sampling over a wide geographic area along the U.S. 
coasts. In 2005, these twenty ports received approximately 60 percent 
of the vessel calls to the U.S. from ships of 10,000 DWT or 
greater.\116\
---------------------------------------------------------------------------

    \116\ ``Vessel Calls at U.S. & World Ports; 2005,'' U.S. 
Maritime Administration, Office of Statistical and Economic 
Analysis, April 2006, Docket ID EPA-HQ-OAR-2007-0121-0040.

  Table VIII-4.--Contribution of Commercial Marine Vessels a to Mobile
              Source Inventories for Selected Ports in 2002
------------------------------------------------------------------------
                                                   PM2.5
            Port area              NOX percent    percent    SOX percent
------------------------------------------------------------------------
Valdez, AK.......................            4           10           43
Seattle, WA......................           10           20           56
Tacoma, WA.......................           20           38           74
San Francisco, CA................            1            1           31
Oakland, CA......................            8           14           80
LA/Long Beach, CA................            5           10           71
Beaumont, TX.....................            6           20           55
Galveston, TX....................            5           12           47
Houston, TX......................            3           10           41
New Orleans, LA..................           14           24           59
South Louisiana, LA..............           12           24           58
Miami, FL........................           13           25           66
Port Everglades, FL..............            9           20           56
Jacksonville, FL.................            5           11           52
Savannah, GA.....................           24           39           80
Charleston, SC...................           22           33           87
Wilmington, NC...................            7           16           73
Baltimore, MD....................           12           27           69
New York/New Jersey..............            4            9           39
Boston, MA.......................            4            5           30
------------------------------------------------------------------------
\a\ This category includes emissions from Category 3 (C3) propulsion
  engines and C2/3 auxiliary engines used on ocean-going vessels.

2. Inventory Calculation Methodology
    The exhaust emission inventories presented above for commercial 
marine vessels, with Category 3 marine engines, include emissions from 
vessels in-port and from vessels engaged in interport transit. This 
section gives a general overview of the methodology used to estimate 
the emission contribution of these vessels. A more detailed description 
of this inventory analysis is available in the public docket.\117\
---------------------------------------------------------------------------

    \117\ ``Development of Inventories for Commercial Marine Vessels 
with Category 3 Engines,'' U.S. EPA, October 2007.
---------------------------------------------------------------------------

    For the purposes of this analysis, in-port operation includes 
cruising, reduced speed zone, maneuvering, and hotelling. The in-port 
analysis includes operation out to a 25 nautical mile radius from the 
entrance to the port. Interport operation includes ship traffic, within 
the U.S. Exclusive Economic Zone (EEZ), not included as part of the 
port emissions analysis. In general, the EEZ extends to 200 nautical 
miles from the U.S. coast. Exceptions include geographic regions near 
Canada, Mexico and the Bahamas where the EEZ extends less than 200 
nautical miles from the U.S. coast.
    The port inventories are based on detailed emission estimates for 
eleven specific ports. The port inventories were estimated using 
activity data for that port (number of port calls, vessel types and 
typical times in different operating modes) and an emission factor for 
each mode. Emission estimates for all other commercial ports were 
developed by matching each of the other commercial ports to one of the 
eleven specific ports. Matching was based on characteristics of port 
activity, such as predominant vessel types, harbor craft and region of 
the country. The detailed port emissions were then scaled for the other 
commercial ports based on relative port activity.\118\ An exception to 
this is that detailed port inventories for fourteen California ports 
were provided by the California Air Resources Board (ARB).
---------------------------------------------------------------------------

    \118\ Browning, L., Hartley, S., Lindhjem, C., Hoats, A., 
``Commercial Marine Port Inventory Development; Baseline 
Inventories,'' prepared by ICF International and Environ for the 
U.S. Environmental Protection Agency, September 2006, Docket ID EPA-
HQ-OAR-2007-0121-0037.
---------------------------------------------------------------------------

    To calculate the mobile fractions in Table VIII-4, we compared 
commercial marine port inventory estimates described above to county-
level mobile source emission estimates developed in support of the 
recent rulemaking for national PM ambient air quality standards.\119\ 
Both propulsion engines and auxiliary engines are included in these 
estimates. The county-level inventories were adjusted to include the 
updated emissions estimates for commercial marine vessels.
---------------------------------------------------------------------------

    \119\ Regulatory Impact Analysis for the Review of the 
Particulate Matter National Ambient Air Quality Standards, EPA 
Docket: EPA-HQ-OAR-2006-0834-0048.3.
---------------------------------------------------------------------------

    Recently, the California Air Resources Board (ARB) sponsored the 
development of new national inventory estimates for Category 3 marine 
engines.\120\ The new approach captures actual interport activity, by 
using information on ship movements, ship attributes, and the distances 
of routes. We believe that this methodology is an improvement over past 
evaluations of interport shipping emissions which were based on 
estimates of ton-miles of

[[Page 69548]]

cargo moved. The new methodology captures ship traffic more completely 
which results in much higher estimates of total emissions from 
commercial marine vessels engaged in interport traffic within the U.S. 
EEZ.
---------------------------------------------------------------------------

    \120\ Corbett, J., PhD, Wang, C., PhD, Firestone, J., PhD., 
``Estimation, Validation, and Forecasts of Regional Commercial 
Marine Vessel Inventories, Tasks 1 and 2: Baseline Inventory and 
Ports Comparison; Final Report,'' University of Delaware, May 3, 
2006, Available electronically at http://www.arb.ca.gov/research/seca/jctask12.pdf, Docket ID EPA-HQ-OAR-2007-0121-0038.
---------------------------------------------------------------------------

    Our emission inventory estimates for interport traffic are based on 
the ARB-sponsored study with four primary 
modifications.121 122 First, we use only the interport 
traffic estimates from the study and rely on our own, more detailed, 
analysis of in-port emissions. Second, we modified the geographic 
boundaries of the inventory to align with the U.S. EEZ. Third, we use 
adjusted emission factors for PM emissions to better reflect the sum of 
available PM emissions data from engines on marine vessels.
---------------------------------------------------------------------------

    \121\ ``Recalculation of Baseline and 2005 Emissions and Fuel 
Consumption,'' memorandum from Lou Browning, ICF and Chris Lindhjem 
and Lyndsey Parker, Environ, to Penny Carey, Mike Samulski, and Russ 
Smith, U.S. EPA, July 19, 2007.
    \122\``U.S. and Regional Totals of Marine Vessel Emissions and 
Fuel Consumption under WA 0-2 Tasks 6 and 7,'' draft memorandum from 
Abby Hoats and Chris Lindhjem, Environ, to Lou Browning, ICF 
International, April 23, 2007.
---------------------------------------------------------------------------

    The detailed inventory studies described above were performed for 
2002. To calculate emission inventories for future years, we applied 
separate growth rates for the West Coast, Gulf Coast, East Coast, and 
Great Lakes. These emission inventory growth estimates were determined 
based on economic growth projections of trade between the United States 
and other regions of the world.\123\ In contrast, the ARB-sponsored 
study looks at a range of growth rates based on extrapolations of 
historical growth in installed power.\124\ The approach used by EPA is 
more conservative in that it uses lower growth rate projections.
---------------------------------------------------------------------------

    \123\ ``RTI Estimates of Growth in Bunker Fuel Consumption,'' 
memorandum from Michael Gallaher and Martin Ross, RTI International, 
to Barry Garelick and Russ Smith, U.S. EPA, April 24, 2006, Docket 
ID EPA-HQ-OAR-2007-0121-0039.
    \124\ Corbett, J., PhD, Wang, C., PhD, ``Estimation, Validation, 
and Forecasts of Regional Commercial Marine Vessel Inventories, 
Tasks 3 and 4: Forecast Inventories for 2010 and 2020; Final 
Report,'' University of Delaware, May 3, 2006, Docket ID EPA-HQ-OAR-
2007-0121-0012.
---------------------------------------------------------------------------

    The inventory estimates include emissions from both U.S. flagged 
vessels and foreign flagged vessels. The majority of the ship operation 
near the U.S. coast is from ships that are not registered in the United 
States. According to the U.S. Maritime Administration, in 2005, 
approximately 87 percent of the calls by ocean-going vessels (10,000 
dead weight tons or greater) at U.S. ports were made by foreign 
vessels.\125\
---------------------------------------------------------------------------

    \125\ ``Vessel Calls at U.S. & World Ports; 2005,'' U.S. 
Maritime Administration, Office of Statistical and Economic 
Analysis, April 2006, Docket ID EPA-HQ-OAR-2007-0121-0040.
---------------------------------------------------------------------------

    This inventory analysis includes emissions from Category 3 
propulsion engines and the Category 2 and 3 auxiliary engines used on 
these vessels. Based on our emissions inventory analysis, auxiliary 
engines contribute approximately half of the exhaust emissions from 
vessels in port. In contrast, auxiliary engines only represent about 4 
percent of the exhaust emissions from ships engaged in interport 
traffic.
    The exhaust emission inventory for commercial marine vessels with 
Category 3 marine engines includes operation that extends out to 200 
nautical miles from shore. Considering all emissions from ships 
operating in the U.S. EEZ, emissions in ports contribute to less than 
20 percent of the total inventory. However, we recognize that emissions 
closer to shore are more likely to impact human health and welfare 
because of their proximity to human populations. We have initiated 
efforts to perform air quality modeling to quantify these impacts. The 
air quality modeling will consider transport of emissions over the 
ocean, meteorological data, population densities, emissions from other 
sources, and other relevant information. We request comment on the 
methodology used to develop exhaust inventory estimates for ships with 
Category 3 engines operating near the U.S. coast.
    As discussed above, the national inventories presented here are for 
the Exclusive Economic Zone around the 50 states. Note that the ship 
traffic in the EEZ includes not only direct movements to and from U.S. 
ports but also movements up and down the coast. The boundaries for the 
EEZ are presented in Figure VIII-1.

BILLING CODE 6560-50-P

[[Page 69549]]

[GRAPHIC] [TIFF OMITTED] TP07DE07.025

BILLING CODE 6560-50-C
    Table VIII-5 presents the 2002 national exhaust emission inventory 
for commercial marine vessels, with Category 3 marine engines, 
subdivided into the seven regions shown in the above figure. The Alaska 
and Hawaii regions contribute to roughly one-fifth of the national 
emissions inventory. The inventory for the Alaska EEZ includes 
emissions from ships on a great circle route, along the Aleutian 
Islands, between Asia and the U.S. West Coast. Therefore, eastern 
Alaska, which includes most of the state population, is presented 
separately in the table below. The Hawaii EEZ includes major shipping 
lanes across the Pacific that pass near the Hawaiian isles.

[[Page 69550]]



                  Table VIII-5.--2002 Regional U.S. Emissions From Commercial Marine Vessels a
                                                    [Tons/yr]
----------------------------------------------------------------------------------------------------------------
                                                                  NOX [short      PM2.5 [short      SOX [short
                            Region                                  tons]            tons]            tons]
----------------------------------------------------------------------------------------------------------------
South Pacific................................................          116,057            8,283           62,944
North Pacific................................................           28,941            2,205           16,469
East Coast...................................................          243,261           17,901          153,597
Gulf Coast...................................................          192,130           14,374          110,382
Alaska (east)................................................           20,078            1,458           11,037
Alaska (west)................................................           66,768            4,799           35,998
Hawaii.......................................................           60,501            4,372           32,970
Great Lakes (U.S. only)......................................           16,708            1,207            9,098
Great Lakes (Canada only)....................................            5,621              405            3,043
                                                              --------------------------------------------------
    Total (using U.S. only Great Lakes)......................          744,444           54,599         432,496
----------------------------------------------------------------------------------------------------------------
\a\ This category includes emissions from Category 3 (C3) propulsion engines and C2/3 auxiliary engines used on
  ocean-going vessels.

B. Potential Costs

    The emission-control technologies we are considering for Category 3 
marine engines are already in development or in commercial use in some 
marine applications. The draft Regulatory Impact Analysis \126\ for the 
May 29, 2002 proposed rulemaking for Category 3 marine engines (67 FR 
37548) included an analysis of regulatory alternatives which included 
advanced technologies. To estimate costs of this prospective emissions 
control program, we expect to start with cost estimates that were 
developed as part of that regulatory analysis. We will modify these 
costs as needed to take into account advances in technology, changes in 
cost structure, and comments received on this ANPRM. We encourage 
commenters to review the information covering all aspects of engine 
costs in the regulatory impact documents for the earlier Category 3 
rulemaking and to provide comments on cost-related issues. In addition, 
we are interested in cost information associated with potential 
retrofitting concepts and in information about any unique costs 
associated with equipment redesign for the marine market.
---------------------------------------------------------------------------

    \126\ ``Draft Regulatory Support Document: Control of Emissions 
from Compression-Ignition Marine Diesel Engines at or Above 30 
Liters per Cylinder,'' U.S. Environmental Protection Agency, April, 
2002.
---------------------------------------------------------------------------

    We will also consider the economics of desulfurizing residual fuel, 
using of distillate fuel, and blending high and low sulfur fuels. Due 
to high refinery production costs, it is not likely that much new 
volume of residual fuel will be desulfurized. We expect to employ a 
worldwide refinery modeling analysis to estimate the cost for 
desulfurizing residual fuel and to estimate the cost for the production 
of additional distillate fuel in our analysis for different fuel volume 
scenarios. Additionally, we will estimate scrubbing costs and potential 
scrubber penetration rates for ships, as the use of scrubbers is 
another method that ships may use to comply, in lieu of using low 
sulfur fuel. The resulting fuel cost from our refinery analysis will be 
compared to the costs from scrubbing and fuel blending to determine the 
most economical method for complying with the standards for Category 3 
marine engines. We request comment on the potential costs of low sulfur 
marine fuels.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under section (3)(f)(1) Executive Order 12866 (58 FR 51735, October 
4, 1993), the Agency must determine whether the regulatory action is 
``significant'' and therefore subject to review by the Office of 
Management and Budget (OMB) and the requirements of this Executive 
Order. This Advance Notice has been sent to the Office of Management 
and Budget (OMB) for review under Executive Order 12866 and any changes 
made in response to OMB recommendations have been documented in the 
docket for this action.

B. Paperwork Reduction Act

    We will prepare information collection requirements as part of our 
proposed rule and submit them for approval to the Office of Management 
and Budget (OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et 
seq.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) as amended by the Small 
Business Regulatory Enforcement Fairness Act (SBREFA), requires 
agencies to endeavor, consistent with the objectives of the rule and 
applicable statutes, to fit regulatory and information requirements to 
the scale of businesses, organizations, and governmental jurisdictions 
subject to their regulations. SBREFA amended the RFA to strengthen its 
analytical and procedural requirements and to ensure that small 
entities are adequately considered during rule development. The Agency 
accordingly requests comment on the potential impacts on a small entity 
of the program described in this notice. These comments will help the 
Agency meet its obligations under SBREFA and will suggest how EPA can 
minimize the impacts of this rule for small entities that may be 
adversely impacted.
    Depending on the number of small entities identified prior to the 
proposal and the level of any contemplated regulatory action, we may 
convene a Small Business Advocacy Review Panel under section 609(b) of 
the Regulatory Flexibility Act as amended by SBREFA. The purpose of the 
Panel would be to collect the advice and recommendations of 
representatives of small entities that could be impacted by the 
eventual rule. If we determine that a panel is not warranted, we would 
intend to work on a less formal basis with those small entities 
identified.
    Although we do not believe that this rule will have a significant 
economic impact on a substantial number of small entities, we are 
requesting information on small entities potentially impacted by this 
rulemaking. Information on company size, number of employees, annual 
revenues and product lines would be especially useful. Confidential 
business information may be submitted as described under SUPPLEMENTARY 
INFORMATION.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private

[[Page 69551]]

sector. Under section 202 of the UMRA, EPA generally must prepare a 
written statement, including a cost-benefit analysis, for proposed and 
final rules with ``Federal mandates'' that may result in expenditures 
to State, local, and tribal governments, in the aggregate, or to the 
private sector, of $100 million or more in any one year. Before 
promulgating an EPA rule for which a written statement is needed, 
section 205 of the UMRA generally requires EPA to identify and consider 
a reasonable number of regulatory alternatives and adopt the least 
costly, most cost-effective or least burdensome alternative that 
achieves the objectives of the rule. The provisions of section 205 do 
not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially affected small governments, enabling 
officials of affected small governments to have meaningful and timely 
input in the development of EPA regulatory proposals with significant 
Federal intergovernmental mandates, and informing, educating, and 
advising small governments on compliance with the regulatory 
requirements.
    As part of the development of our Notice of Proposed Rulemaking, we 
will examine the impacts of our proposal with respect to expected 
expenditures by State, local, and tribal governments, in the aggregate, 
or by the private sector of $100 million or more in any one year.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    Under Section 6 of Executive Order 13132, EPA may not issue a 
regulation that has federalism implications, that imposes substantial 
direct compliance costs, and that is not required by statute, unless 
the Federal government provides the funds necessary to pay the direct 
compliance costs incurred by State and local governments, or EPA 
consults with State and local officials early in the process of 
developing the proposed regulation. EPA also may not issue a regulation 
that has federalism implications and that preempts State law, unless 
the Agency consults with State and local officials early in the process 
of developing the proposed regulation.
    Section 4 of the Executive Order contains additional requirements 
for rules that preempt State or local law, even if those rules do not 
have federalism implications (i.e., the rules will not have substantial 
direct effects on the States, on the relationship between the national 
government and the states, or on the distribution of power and 
responsibilities among the various levels of government). Those 
requirements include providing all affected State and local officials 
notice and an opportunity for appropriate participation in the 
development of the regulation. If the preemption is not based on 
express or implied statutory authority, EPA also must consult, to the 
extent practicable, with appropriate State and local officials 
regarding the conflict between State law and Federally protected 
interests within the agency's area of regulatory responsibility.
    As part of the development of our Notice of Proposed Rulemaking, we 
will examine the impacts of our proposal with respect to the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, as specified in Executive Order 13132.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

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

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' ``Policies that have tribal 
implications'' is defined in the Executive Order to include regulations 
that have ``substantial direct effects on one or more Indian tribes, on 
the relationship between the Federal government and the Indian tribes, 
or on the distribution of power and responsibilities between the 
Federal government and Indian tribes.''
    As part of the development of our Notice of Proposed Rulemaking, we 
will examine the impacts of our proposal with respect to tribal 
implications.

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

    Executive Order 13045, ``Protection of Children From Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) Is determined to be ``economically significant'' 
as defined under Executive Order 12866, and (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    This rule is not subject to the Executive Order because it does not 
involve decisions on environmental health or safety risks that may 
disproportionately affect children. The EPA believes that the emissions 
reductions from the strategies proposed in this rulemaking will further 
improve air quality and will further improve children's health.

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

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355 
(May 22, 2001)) requires that we determine whether or not there is a 
significant impact on the supply of energy caused by our rulemaking. 
These impacts include: Reductions in supply, reductions in production, 
increases in energy usage, increases in the cost of energy production 
and distribution, or other similarly adverse outcomes. We anticipate 
that our proposal will not be a ``significant energy action'' as 
defined by this order because we are not reducing the supply or 
production of any fuels or electricity, nor are we increasing the use 
or cost of energy by more than the stated thresholds. The

[[Page 69552]]

proposed standards will have for their aim the reduction of emissions 
from certain marine engines using either exhaust gas cleaning 
technology or an alternative grade of marine fuel, and will have no 
effect on fuel formulation.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104 113, section 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless doing so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. NTTAA directs EPA to 
provide Congress, through OMB, explanations when the Agency decides not 
to use available and applicable voluntary consensus standards.
    As part of the development of our Notice of Proposed Rulemaking, we 
will examine the availability and use of voluntary consensus standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it increases the 
level of environmental protection for all affected populations without 
having any disproportionately high and adverse human health or 
environmental effects on any population, including any minority or low-
income population. Rather the opposite as more low-income individuals 
tend to live closer to marine ports, and it is these areas that will 
receive the most benefits in this rule that will reduce emissions of 
large marine engines.

List of Subjects

40 CFR Part 9

    Reporting and recordkeeping requirements.

40 CFR Part 94

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Confidential business information, Imports, 
Incorporation by reference, Penalties, Reporting and recordkeeping 
requirements, Vessels, Warranties.

    Dated: November 29, 2007.
Stephen L. Johnson,
Administrator.
 [FR Doc. E7-23556 Filed 12-6-07; 8:45 am]
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