Approval and Promulgation of Implementation Plans; State of Oregon; Regional Haze State Implementation Plan, 12651-12664 [2011-5198]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 76, Number 45 (Tuesday, March 8, 2011)]
[Proposed Rules]
[Pages 12651-12664]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-5198]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2011-0035, FRL-9276-6]


Approval and Promulgation of Implementation Plans; State of 
Oregon; Regional Haze State Implementation Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve a State Implementation Plan (SIP) 
revision, submitted by the State of Oregon on December 20, 2010, with 
supplemental information submitted February 1, 2011, as meeting the 
requirements of Clean Air Act (CAA) section 110(a)(2)(D)(i)(II) as it 
applies to visibility for the 1997 8-hour ozone and 1997 particulate 
matter (PM2.5) National Ambient Air Quality Standards 
(NAAQS). EPA is also proposing to approve a portion of the SIP 
submittal, as meeting certain requirements of the regional haze 
program, including the Federal regulations for best available retrofit 
technology (BART).

DATES: Written comments must be received at the address below on or 
before April 7, 2011.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2011-0035, by one of the following methods:
     https://www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     E-mail: Keith Rose at R10-Public_Comments@epa.gov.
     Mail: Keith Rose, EPA Region 10, Office of Air, Waste and 
Toxics, AWT-107, 1200 Sixth Avenue, Suite 900, Seattle, WA 98101.
     Hand Delivery/Courier: EPA Region 10, 1200 Sixth Avenue, 
Suite 900, Seattle, WA 98101. Attention: Keith Rose, Office of Air, 
Waste and Toxics, AWT-107. Such deliveries are only accepted during 
normal hours of operation, and special arrangements should be made for 
deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R10-OAR-
2011-0035. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
https://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 https://www.regulations.gov or e-mail. The https://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 https://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 https://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the https://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 form. Publicly available docket materials are available either 
electronically at https://www.regulations.gov or in hard copy at the 
Office of Air, Waste and Toxics, EPA Region 10, 1200 Sixth Avenue, 
Seattle, WA 98101. EPA requests that if at all possible, you contact 
the individual listed below to view the hard copy of the docket.

FOR FURTHER INFORMATION CONTACT: Mr. Keith Rose at telephone number 
(206) 553-1949, rose.keith@epa.gov or the above EPA, Region 10 address.

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA. Information is organized 
as follows:

Table of Contents

I. Background for EPA's Proposed Action
    A. Definition of Regional Haze
    B. Regional Haze Rules and Regulations
    C. Roles of Agencies in Addressing Regional Haze
    D. Interstate Transport for Visibility
II. Requirements for Regional Haze SIPs
    A. The CAA and the Regional Haze Rule
    B. Determination of Baseline, Natural, and Current Visibility 
Conditions
    C. Consultation With States and Federal Land Managers
    D. Best Available Retrofit Technology
III. EPA's Analysis of Oregon's Regional Haze SIP
    A. Affected Class I Areas
    B. Baseline and Natural Conditions and Uniform Rate of Progress
    C. Oregon Emissions Inventories
    D. Sources of Visibility Impairment in Oregon Class I Areas
    E. Best Available Retrofit Technology (BART)
IV. EPA's Analysis of Oregon's Regional Haze Rules
V. EPA's Analysis of Whether the Oregon Regional Haze SIP Submittal 
Meets Interstate Transport Requirements
VI. What action is EPA proposing?
VII. Oregon Notice Provision
VIII. Statutory and Executive Order Reviews

I. Background for EPA's Proposed Action

    In the CAA Amendments of 1977, Congress established a program to 
protect and improve visibility in the national parks and wilderness 
areas. See CAA section 169(A). Congress amended the visibility 
provisions in the CAA in 1990 to focus attention on the problem of 
regional haze. See CAA section 169(B). EPA promulgated regulations in 
1999 to implement sections 169A and 169B of the Act. These regulations 
require States to develop and implement plans to ensure reasonable 
progress toward improving visibility in mandatory Class I Federal areas 
\1\ (Class

[[Page 12652]]

I areas). 64 FR 35714 (July 1, 1999); see also 70 FR 39104 (July 6, 
2005) and 71 FR 60612 (October 13, 2006).
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    \1\ Areas designated as mandatory Class I Federal areas consist 
of national parks exceeding 6000 acres, wilderness areas and 
national memorial parks exceeding 5000 acres, and all international 
parks that were in existence on August 7, 1977. 42 U.S.C. 7472(a). 
In accordance with section 169A of the CAA, EPA, in consultation 
with the Department of Interior, promulgated a list of 156 areas 
where visibility is identified as an important value. 44 FR 69122 
(November 30, 1979). The extent of a mandatory Class I area includes 
subsequent changes in boundaries, such as park expansions. 42 U.S.C. 
7472(a). Although States and Tribes may designate as Class I 
additional areas which they consider to have visibility as an 
important value, the requirements of the visibility program set 
forth in section 169A of the CAA apply only to ``mandatory Class I 
Federal areas.'' Each mandatory Class I Federal area is the 
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i). 
When we use the term ``Class I area'' in this action, we mean a 
``mandatory Class I Federal area.''
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    In this action, EPA is proposing to approve certain provisions of 
Oregon's Regional Haze SIP submission addressing the requirements for 
best available retrofit technology (BART), the calculation of baseline 
and natural visibility conditions, and the statewide inventory of 
visibility-impairing pollutants. EPA is also proposing to approve the 
provisions of Oregon's SIP submittal addressing BART as meeting 
Oregon's obligations under section 110(a)(2)(D)(i)(II) of the CAA for 
visibility. EPA is not taking action today on those provisions of the 
Regional Haze SIP submittal related to reasonable progress goals and 
the long term strategy.

A. Definition of Regional Haze

    Regional haze is impairment of visual range or colorization caused 
by emission of air pollution produced by numerous sources and 
activities, located across a broad regional area. The sources include 
but are not limited to, major and minor stationary sources, mobile 
sources, and area sources including non-anthropogenic sources. 
Visibility impairment is primarily caused by fine particulate matter 
(PM2.5) or secondary aerosol formed in the atmosphere from 
precursor gasses (e.g., sulfur dioxide, nitrogen oxides, and in some 
cases, ammonia and volatile organic compounds). Atmospheric fine 
particulate reduces clarity, color, and visual range of visual scenes. 
Visibility-reducing fine particulates are primarily composed of 
sulfate, nitrate, organic carbon compounds, elemental carbon, and soil 
dust, and impair visibility by scattering and absorbing light. Fine 
particulate can also cause serious health effects and mortality in 
humans, and contributes to environmental effects such as acid 
deposition and eutrophication.\2\
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    \2\ See 64 FR at 35715.
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    Data from the existing visibility monitoring network, the 
``Interagency Monitoring of Protected Visual Environments'' (IMPROVE) 
monitoring network, show that visibility impairment caused by air 
pollution occurs virtually all the time at most national parks and 
wilderness areas. Average visual range in many Class I areas in the 
Western United States is 100-150 kilometers, or about one-half to two-
thirds the visual range that would exist without anthropogenic air 
pollution.\3\ Visibility impairment also varies day-to-day and by 
season depending on variation in meteorology and emission rates.
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    \3\ Id.
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B. Regional Haze Rules and Regulations

    In section 169A of the 1977 CAA Amendments, Congress created a 
program for protecting visibility in the nation's national parks and 
wilderness areas. This section of the CAA establishes as a national 
goal the ``prevention of any future, and the remedying of any existing, 
impairment of visibility in Class I areas which impairment results from 
manmade air pollution.'' CAA section 169A(a)(1). On December 2, 1980, 
EPA promulgated regulations to address visibility impairment in Class I 
areas that is ``reasonably attributable'' to a single source or small 
group of sources, i.e., ``reasonably attributable visibility 
impairment''. See 45 FR 80084. These regulations represented the first 
phase in addressing visibility impairment. EPA deferred action on 
regional haze that emanates from a variety of sources until monitoring, 
modeling, and scientific knowledge about the relationships between 
pollutants and visibility impairment were improved.
    Congress added section 169B to the CAA in 1990 to address regional 
haze issues. EPA promulgated a rule to address regional haze on July 1, 
1999 (64 FR 35713) (the RHR). The RHR revised the existing visibility 
regulations to integrate into the regulation provisions addressing 
regional haze impairment and established a comprehensive visibility 
protection program for Class I areas. The requirements for regional 
haze, found at 40 CFR 51.308 and 51.309, are included in EPA's 
visibility protection regulations at 40 CFR 51.300-309. Some of the 
main elements of the regional haze requirements are summarized in 
section III of this rulemaking. The requirement to submit a regional 
haze SIP applies to all 50 States, the District of Columbia and the 
Virgin Islands.\4\ 40 CFR 51.308(b) requires States to submit the first 
implementation plan addressing regional haze visibility impairment no 
later than December 17, 2007.
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    \4\ Albuquerque/Bernalillo County in New Mexico must also submit 
a regional haze SIP to completely satisfy the requirements of 
section 110(a)(2)(D) of the CAA for the entire State of New Mexico 
under the New Mexico Air Quality Control Act (section 74-2-4).
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C. Roles of Agencies in Addressing Regional Haze

    Successful implementation of the Regional Haze Program will require 
long-term regional coordination among States, Tribal governments, and 
various Federal agencies. As noted above, pollution affecting the air 
quality in Class I areas can be transported over long distances, even 
hundreds of kilometers. Therefore, to effectively address the problem 
of visibility impairment in Class I areas, States need to develop 
strategies in coordination with one another, taking into account the 
effect of emissions from one jurisdiction on the air quality in 
another.
    Because the pollutants that lead to regional haze impairment can 
originate from across State lines, EPA has encouraged the States and 
Tribes to address visibility impairment from a regional perspective. 
Five regional planning organizations \5\ (RPOs) were created nationally 
to address regional haze and related issues. One of the main objectives 
of the RPOs is to develop and analyze data and conduct pollutant 
transport modeling to assist the States or Tribes in developing their 
regional haze plans.
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    \5\ See https://www.epa.gov/air/visibility/regional.html for 
description of the regional planning organizations.
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    The Western Regional Air Partnership (WRAP),\6\ one of the five 
RPOs nationally, is a voluntary partnership of State, Tribal, Federal, 
and local air agencies dealing with air quality in the West. WRAP 
member States include: Alaska, Arizona, California, Colorado, Idaho, 
Montana, New Mexico, North Dakota, Oregon, South Dakota, Utah, 
Washington, and Wyoming. WRAP Tribal members include Campo Band of 
Kumeyaay Indians, Confederated Salish and Kootenai Tribes, Cortina 
Indian Rancheria, Hopi Tribe, Hualapai Nation of the Grand Canyon, 
Native Village of Shungnak, Nez Perce Tribe, Northern Cheyenne Tribe, 
Pueblo of Acoma, Pueblo of San Felipe, and Shoshone-Bannock Tribes of 
Fort Hall.
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    \6\ The WRAP Web site can be found at https://www.wrapair.org.

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[[Page 12653]]

D. Interstate Transport for Visibility

    On July 18, 1997, EPA promulgated new NAAQS for 8-hour ozone and 
for PM2.5. 62 FR 38652. Section 110(a)(1) of the CAA 
requires States to submit a plan to address certain requirements for a 
new or revised NAAQS within three years after promulgation of such 
standards, or within such shorter time as EPA may prescribe. Section 
110(a)(2) of the CAA lists the elements that such new plan submissions 
must address, as applicable, including section 110(a)(2)(D)(i), which 
pertains to the interstate transport of certain emissions.
    On April 25, 2005, EPA published a ``Finding of Failure to Submit 
SIPs for Interstate Transport for the 8-hour Ozone and PM2.5 
NAAQS.'' 70 FR 21147. This included a finding that Oregon and other 
States had failed to submit SIPs to address interstate transport of 
emissions affecting visibility and started a 2-year clock for the 
promulgation of Federal Implementation Plans (FIPs) by EPA, unless the 
States made submissions to meet the requirements of section 
110(a)(2)(D)(i) and EPA approves such submissions. Id.
    On August 15, 2006, EPA issued guidance on this topic entitled 
``Guidance for State Implementation Plan (SIP) Submissions to Meet 
Current Outstanding Obligations Under section 110(a)(2)(D)(i) for the 
8-Hour Ozone and PM2.5 National Ambient Air Quality 
Standards'' (2006 Guidance). We developed the 2006 Guidance to make 
recommendations to States for making submissions to meet the 
requirements of section 110(a)(2)(D)(i) for the 1997 8-hour ozone 
standards and the 1997 PM2.5 standards.
    As identified in the 2006 Guidance, the ``good neighbor'' 
provisions in section 110(a)(2)(D)(i) of the CAA require each State to 
have a SIP that prohibits emissions that adversely affect other States 
in ways contemplated in the statute. Section 110(a)(2)(D)(i) contains 
four distinct requirements related to the impacts of interstate 
transport. The SIP must prevent sources in the State from emitting 
pollutants in amounts which will: (1) Contribute significantly to 
nonattainment of the NAAQS in other States; (2) interfere with 
maintenance of the NAAQS in other States; (3) interfere with provisions 
to prevent significant deterioration of air quality in other States; or 
(4) interfere with efforts to protect visibility in other States.
    With respect to establishing that emissions from sources in the 
State would not interfere with measures in other States to protect 
visibility, the 2006 Guidance recommended that States make a submission 
indicating that it was premature, at that time, to determine whether 
there would be any interference with measures in the applicable SIP for 
another State designed to ``protect visibility'' until the submission 
and approval of regional haze SIPs. Regional haze SIPs were required to 
be submitted by December 17, 2007. See 74 FR 2392. At this later point 
in time, however, EPA believes it is now necessary to evaluate such 
110(a)(2)(D)(i) submissions from a State to ensure that the existing 
SIP, or the SIP as modified by the submission, contains adequate 
provisions to prevent interference with the visibility programs of 
other States, such as for consistency with the assumptions for controls 
relied upon by other States in establishing reasonable progress goals 
to address regional haze.
    The Regional Haze Program, as reflected in the RHR, recognizes the 
importance of addressing the long-range transport of pollutants for 
visibility and encourages States to work together to develop plans to 
address haze. The regulations explicitly require each State to address 
its ``share'' of the emission reductions needed to meet the reasonable 
progress goals for neighboring Class I areas. States, working together 
through a regional planning process, are required to address an agreed-
upon share of their contribution to visibility impairment in the Class 
I areas of their neighbors. 40 CFR 51.308(d)(3)(ii). Given these 
requirements, we anticipate that regional haze SIPs will contain 
measures that will achieve these emissions reductions, and that these 
measures will meet the requirements of section 110(a)(2)(D)(i).
    As a result of the regional planning efforts in the West, all 
States in the WRAP region contributed information to a Technical 
Support System (TSS) which provides an analysis of the causes of haze, 
and the levels of contribution from all sources within each State to 
the visibility degradation of each Class I area. The WRAP States 
consulted in the development of reasonable progress goals, using the 
products of this technical consultation process to co-develop their 
reasonable progress goals for the Western Class I areas. The modeling 
done by the WRAP relied on assumptions regarding emissions over the 
relevant planning period and embedded in these assumptions were 
anticipated emissions reductions in each of the States in the WRAP, 
including reductions from BART and other measures to be adopted as part 
of the State's long term strategy for addressing regional haze. The 
reasonable progress goals in the draft and final regional haze SIPs 
that have now been prepared by States in the West accordingly are 
based, in part, on the emissions reductions from nearby States that 
were agreed on through the WRAP process.
    Oregon submitted a Regional Haze SIP on July 16, 2009 to address 
the requirements of the RHR. On September 11, 2009, EPA determined that 
this SIP submission was complete. Oregon submitted a revised Regional 
Haze SIP on December 20, 2010, replacing the July 2009 submission. On 
February 1, 2011, Oregon provided EPA additional information to address 
the requirements of the RHR and the good neighbor provisions of section 
110(a)(2)(D)(i)(II)) of the Act, regarding visibility for the 1997 8-
hour ozone NAAQS and the 1997 PM2.5 NAAQS. EPA has reviewed 
the submittal and concluded at this time to propose to take action on 
only certain elements of Oregon's Regional Haze SIP. EPA is required to 
take final action either to approve Oregon's SIP submittal, or 
otherwise to take action to meet the requirements of section 
110(a)(2)(D)(i)(II) regarding visibility on or before June 21, 2011.\7\ 
EPA is proposing to find that certain elements of Oregon's Regional 
Haze SIP submittal meet these requirements. In particular, as explained 
in section V of this action, EPA is proposing to find that the BART 
measures in Oregon's Regional Haze SIP submittal, which EPA is 
proposing to approve in this action, will also mean that the Oregon SIP 
meets the requirements of section 110(a)(2)(D)(i)(II) regarding 
visibility for the 1997 8-hour ozone and 1997 PM2.5 NAAQS.
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    \7\ Wildearth Guardians v. Jackson, Case No. 4:09-CV-02453-CW 
(N.D. Calif) (as modified by Jan 14, 2011 Order Granting Motion to 
Modify Consent Decree).
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II. Requirements for Regional Haze SIPs

A. The CAA and the Regional Haze Rule

    Regional haze SIPs must assure reasonable progress towards the 
national goal of achieving natural visibility conditions in Class I 
areas. Section 169A of the CAA and EPA's implementing regulations 
require States to establish long-term strategies for making reasonable 
progress toward meeting this goal. Implementation plans must also give 
specific attention to certain stationary sources that were in existence 
on August 7, 1977, but were not in operation before August 7, 1962, and 
require these sources, where appropriate, to install BART controls for

[[Page 12654]]

the purpose of eliminating or reducing visibility impairment. The 
specific regional haze SIP requirements are discussed in further detail 
below.

B. Determination of Baseline, Natural, and Current Visibility 
Conditions

    The RHR establishes the deciview (dv) as the principal metric for 
measuring visibility. This visibility metric expresses uniform changes 
in haziness in terms of common increments across the entire range of 
visibility conditions, from pristine to extremely hazy conditions. 
Visibility is determined by measuring the visual range (or deciview), 
which is the greatest distance, in kilometers or miles, at which a dark 
object can be viewed against the sky. The deciview is a useful measure 
for tracking progress in improving visibility, because each deciview 
change is an equal incremental change in visibility perceived by the 
human eye. Most people can detect a change in visibility at one 
deciview.\8\
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    \8\ The preamble to the RHR provides additional details about 
the deciview. 64 FR 35714, 35725 (July 1,1999).
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    The deciview is used in expressing reasonable progress goals (which 
are interim visibility goals towards meeting the national visibility 
goal), defining baseline, current, and natural conditions, and tracking 
changes in visibility. The regional haze SIPs must contain measures 
that ensure ``reasonable progress'' toward the national goal of 
preventing and remedying visibility impairment in Class I areas caused 
by manmade air pollution by reducing anthropogenic emissions that cause 
regional haze. The national goal is a return to natural conditions, 
i.e., anthropogenic sources of air pollution would no longer impair 
visibility in Class I areas.
    To track changes in visibility over time at each of the 156 Class I 
areas covered by the visibility program (40 CFR 81.401-437), and as 
part of the process for determining reasonable progress, States must 
calculate the degree of existing visibility impairment at each Class I 
area at the time of each regional haze SIP submittal and periodically 
review progress every five years midway through each 10-year 
implementation period. To do this, the RHR requires States to determine 
the degree of impairment (in deciviews) for the average of the 20% 
least impaired (``best'') and 20% most impaired (``worst'') visibility 
days over a specified time period at each of their Class I areas. In 
addition, States must also develop an estimate of natural visibility 
conditions for the purpose of comparing progress toward the national 
goal. Natural visibility is determined by estimating the natural 
concentrations of pollutants that cause visibility impairment, and then 
calculating total light extinction based on those estimates. EPA has 
provided guidance to States regarding how to calculate baseline, 
natural and current visibility conditions in documents titled, EPA's 
Guidance for Estimating Natural Visibility Conditions Under the 
Regional Haze Rule, September 2003, (EPA-454/B-03-005 located at https://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf), (hereinafter 
referred to as ``EPA's 2003 Natural Visibility Guidance''), and 
Guidance for Tracking Progress Under the Regional Haze Rule (EPA-454/B-
03-004 September 2003 located at https://www.epa.gov/ttncaaa1/t1/memoranda/rh_tpurhr_gd.pdf), (hereinafter referred to as ``EPA's 2003 
Tracking Progress Guidance'').
    For the first regional haze SIPs that were due by December 17, 
2007, ``baseline visibility conditions'' were the starting points for 
assessing ``current'' visibility impairment. Baseline visibility 
conditions represent the degree of visibility impairment for the 20% 
least impaired days and 20% most impaired days for each calendar year 
from 2000 to 2004. Using monitoring data for 2000 through 2004, States 
are required to calculate the average degree of visibility impairment 
for each Class I area, based on the average of annual values over the 
five-year period. The comparison of initial baseline visibility 
conditions to natural visibility conditions indicates the amount of 
improvement necessary to attain natural visibility, while the future 
comparison of baseline conditions to the then-current conditions will 
indicate the amount of progress made. In general, the 2000-2004 
baseline time period is considered the time from which improvement in 
visibility is measured.

C. Consultation With States and Federal Land Managers

    The RHR requires that States consult with Federal Land Managers 
(FLMs) before adopting and submitting their SIPs. See 40 CFR 51.308(i). 
States must provide FLMs an opportunity for consultation, in person and 
at least 60 days prior to holding any public hearing on the SIP. This 
consultation must include the opportunity for the FLMs to discuss their 
assessment of visibility impairment in any Class I area and to offer 
recommendations on the development of the reasonable progress goals and 
on the development and implementation of strategies to address 
visibility impairment. Further, a State must include in its SIP a 
description of how it addressed any comments provided by the FLMs. 
Finally, a SIP must provide procedures for continuing consultation 
between the State and FLMs regarding the State's visibility protection 
program, including development and review of SIP revisions, five-year 
progress reports, and the implementation of other programs having the 
potential to contribute to impairment of visibility in Class I areas.

D. Best Available Retrofit Technology

    Section 169A of the CAA directs States to evaluate the use of 
retrofit controls at certain larger, often uncontrolled, older 
stationary sources in order to address visibility impacts from these 
sources. Specifically, section 169A(b)(2)(A) of the CAA requires States 
to revise their SIPs to contain such measures as may be necessary to 
make reasonable progress towards the natural visibility goal, including 
a requirement that certain categories of existing major stationary 
sources \9\ built between 1962 and 1977 procure, install, and operate 
the ``Best Available Retrofit Technology'' as determined by the State. 
States are directed to conduct BART determinations for such sources 
that may be anticipated to cause or contribute to any visibility 
impairment in a Class I area. Rather than requiring source-specific 
BART controls, States also have the flexibility to adopt an emissions 
trading program or other alternative program as long as the alternative 
provides greater reasonable progress towards improving visibility than 
BART.
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    \9\ The set of ``major stationary sources'' potentially subject 
to BART is listed in CAA section 169A(g)(7).
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    On July 6, 2005, EPA published the Guidelines for BART 
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR 
Part 51 (hereinafter referred to as the ``BART Guidelines'') to assist 
States in determining which of their sources should be subject to the 
BART requirements and in determining appropriate emission limits for 
each applicable source. In making a BART applicability determination 
for a fossil fuel-fired electric generating plant with a total 
generating capacity in excess of 750 megawatts, a State must use the 
approach set forth in the BART Guidelines. A State is encouraged, but 
not required, to follow the BART Guidelines in making BART 
determinations for other types of sources.
    States must address all visibility-impairing pollutants emitted by 
a source

[[Page 12655]]

in the BART determination process. The most significant visibility-
impairing pollutants are sulfur dioxide, nitrogen oxides, and fine 
particulate matter. EPA has indicated that States should use their best 
judgment in determining whether volatile organic compounds or ammonia 
compounds impair visibility in Class I areas.
    Under the BART Guidelines, States may select an exemption threshold 
value for their BART modeling, below which a BART-eligible source would 
not be expected to cause or contribute to visibility impairment in any 
Class I area. The State must document this exemption threshold value in 
the SIP and must state the basis for its selection of that value. Any 
source with emissions that model above the threshold value would be 
subject to a BART determination review. The BART Guidelines acknowledge 
varying circumstances affecting different Class I areas. States should 
consider the number of emission sources affecting the Class I areas at 
issue and the magnitude of the individual sources' impacts. Generally, 
an exemption threshold set by the State should not be higher than 0.5 
deciview.
    In their SIPs, States must identify potential BART sources, 
described as ``BART-eligible sources'' in the RHR, and document their 
BART control determination analyses. The term ``BART-eligible source'' 
used in the BART Guidelines means the collection of individual emission 
units at a facility that together comprises the BART-eligible source. 
In making BART determinations, section 169A(g)(2) of the CAA requires 
that States consider the following factors: (1) The costs of 
compliance, (2) the energy and non-air quality environmental impacts of 
compliance, (3) any existing pollution control technology in use at the 
source, (4) the remaining useful life of the source, and (5) the degree 
of improvement in visibility which may reasonably be anticipated to 
result from the use of such technology. States are free to determine 
the weight and significance to be assigned to each factor.
    A regional haze SIP must include source-specific BART emission 
limits and compliance schedules for each source subject to BART. Once a 
State has made its BART determination, the BART controls must be 
installed and in operation as expeditiously as practicable, but no 
later than five years after the date EPA approves the regional haze 
SIP. CAA section 169(g)(4). 40 CFR 51.308(e)(1)(iv). In addition to 
what is required by the RHR, general SIP requirements mandate that the 
SIP must also include all regulatory requirements related to 
monitoring, recordkeeping, and reporting for the BART controls on the 
source. States have the flexibility to choose the type of control 
measures they will use to meet the requirements of BART.

III. EPA's Analysis of Oregon's Regional Haze SIP

A. Affected Class I Areas

    There are 12 mandatory Class I areas, or portions of such areas 
within Oregon: Mt. Hood Wilderness Area, Mt. Jefferson Wilderness Area, 
Mt Washington Wilderness Area, Kalmiopsis Wilderness Area, Mountain 
Lakes Wilderness Area, Gearhart Mountain Wilderness Area, Crater Lake 
National Park, Diamond Peak Wilderness Area, Three Sisters Wilderness 
Area, Strawberry Mountain Wilderness Area, Eagle Cap Wilderness Area, 
and Hells Canyon Wilderness Area. Hells Canyon Wilderness Area is 
shared with the State of Idaho. See 40 CFR 81.425. Oregon is 
responsible for developing reasonable progress goals (RPGs) for these 
12 Class I areas. Oregon Department of Environmental Quality (ODEQ) 
consulted with the appropriate State air quality agency in Washington, 
Idaho, California, and Nevada to determine Oregon's contribution to 
haze in neighboring States' Class I areas. See chapter 13, section 13.2 
of the Oregon Regional Haze SIP submittal. See also the WRAP Technical 
Support Document, February 28, 2011 (WRAP TSD) supporting this 
action.\10\
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    \10\ EPA evaluated the technical work products of the WRAP used 
by Oregon in support of this Regional Haze SIP submittal. The 
results of that evaluation are included in the WRAP Technical 
Support Document.
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B. Baseline and Natural Conditions and Uniform Rate of Progress

    Oregon, using data from the IMPROVE monitoring network and analyzed 
by WRAP, established baseline and natural visibility conditions as well 
as the uniform rate of progress (URP) to achieve natural visibility 
conditions by 2064 for all Oregon Class I areas within its borders.
    Baseline visibility for the most-impaired (20% worst) days and the 
least-impaired (20% best) days was calculated from monitoring data 
collected by IMPROVE monitors. Not every Class I area has an IMPROVE 
monitor, rather a monitor in a Class I area may represent the air 
quality and visibility conditions for more than a single Class I area. 
The Class I areas that are represented by a monitor in a near-by Class 
I area were determined by the States and the IMPROVE Steering 
Committee. This decision was based on the Class I areas in a group 
having the same general visibility conditions. IMPROVE monitors are 
located in six Oregon Class I areas and represent all 12 Oregon Class I 
areas. Specifically, the Oregon Class I areas are segregated into six 
groups. These groups and Class I areas are:
     North Cascades: Mt. Hood Wilderness Area.
     Central Cascades: Mt. Jefferson, Mt. Washington, and Three 
Sisters Wilderness Areas.
     Southern Cascades: Crater Lake National Park, Diamond 
Peak, Mountain Lakes, and Gearhart Wilderness Areas.
     Coast Range: Kalmiopsis Wilderness Area.
     Eastern Oregon: Strawberry Mountain and Eagle Cap 
Wilderness Areas.
     Eastern Oregon/Western Idaho: Hells Canyon Wilderness 
Area.
    In general, WRAP based their estimates of natural conditions on EPA 
guidance, Guidance for Estimating Natural Visibility Conditions Under 
the Regional Haze Program (EPA-45/B-03-0005 September 2003) but 
incorporated refinements which EPA believes provides results more 
appropriate for western States than the general EPA default approach. 
See section 2.D and 2.E of the WRAP TSD, supporting this action.
    Visibility on 20% worst days during the 2000-04 baseline period for 
each group of Oregon Class I areas is:
     North Cascades--14.9 dv
     Central Cascades--15.3 dv
     Southern Cascades--13.7 dv
     Coast Range--15.5 dv
     Eastern Oregon--18.6 dv
     Eastern Oregon/Western Idaho--18.6 dv
    Visibility on 20% best days during the 2000-04 baseline period for 
each group of Oregon Class I areas is:
     North Cascades--2.2 dv
     Central Cascades--3.0 dv
     Southern Cascades--1.7 dv
     Coast Range--6.3 dv
     Eastern Oregon--4.5 dv
     Eastern Oregon/Western Idaho--5.5 dv
    Natural visibility conditions on the 20% worst days for each group 
of Class I areas are:
     Northern Cascades--8.4 dv
     Central Cascades--8.8 dv
     Southern Cascades--7.6 dv
     Coast Range--9.4 dv
     Eastern Oregon--8.9 dv
     Eastern Oregon/Western Idaho -8.3 dv
    The 2018 Uniform Rate of Progress (URP) goal for the 20% worst days 
in each group of Class I areas is:

[[Page 12656]]

     North Cascades--13.4 dv
     Central Cascades--13.8 dv
     Southern Cascades--12.3 dv
     Coast Range--14.1 dv
     Eastern Oregon -16.3 dv
     Eastern Oregon/Western Idaho--16.2 dv
    Baseline visibility conditions, 2064 natural conditions, and 
reductions needed to achieve the 2018 URP for the 20% worst days for 
each group of Oregon Class I areas are identified in table 6-1 of 
chapter 6 of the Oregon Regional Haze Plan.
    Based on our evaluation of the State's baseline and natural 
conditions analysis, EPA is proposing to find that Oregon has 
appropriately determined baseline visibility for the average 20% worst 
and 20% best days, and natural visibility conditions for the average 
20% worst days in each Oregon Class I area. See sections 2.D and 2.E of 
the WRAP TSD supporting this action.

C. Oregon Emissions Inventories

    There are three main categories of air pollution emission sources: 
point sources, area sources, and mobile sources. Point sources are 
larger stationary sources that emit air pollutants. Area sources are 
large numbers of small sources that are widely distributed across an 
area, such as residential heating units, re-entrained dust from unpaved 
roads or windblown dust from agricultural fields. Mobile sources are 
sources such as motor vehicles, locomotives and aircraft.
    EPA's Regional Haze Rule requires a statewide emission inventory of 
pollutants that are reasonably anticipated to cause or contribute to 
visibility impairment in any mandatory Class I area. 40 CFR 
51.308(d)(4)(v). The WRAP, with data supplied by the States, compiled 
emission inventories for all major source categories in Oregon and 
estimated the 2002 baseline year (based on an average of 2000-2004). 
Oregon also compiled an emission inventory for 2018. Emission estimates 
for 2018 were generated from anticipated population growth, growth in 
industrial activity, and emission reductions from implementation of 
control measures, e.g., implementation of BART limitations and motor 
vehicle tailpipe emissions.
    Chapter 8 of the Oregon Regional Haze SIP submittal discusses how 
emission estimates were determined for statewide emission inventories 
by pollutant and source category. Appendix A of the Oregon Regional 
Haze Plan identifies the Oregon emission inventory by county. Detailed 
estimates of the emissions used in the modeling conducted by the WRAP 
for Oregon can be found at the WRAP Web site: https://vista.cira.colostate.edu/TSS/Results/Emissions.aspx.
    The Oregon Regional Haze SIP submittal identifies total emissions 
for all visibility-impairing pollutants including sulfur dioxide 
(SO2), nitrogen oxides (NOX), volatile organic 
compounds (VOC), organic carbon (OC), elemental carbon (EC), other fine 
particulate (PM2.5), coarse particulate matter (PM coarse), 
and ammonia (NH3). These emission estimates were partitioned 
into nine emission source categories: Point source, area source, on-
road mobile, off-road mobile, anthropogenic fire (prescribed fire and 
agricultural field burning), natural fire, road dust, and fugitive 
dust. See chapter 8.1 of the Oregon Regional Haze SIP submittal for 
additional detail on how the statewide emission inventory was 
developed, and for tables showing the emissions inventory for each 
pollutant by source category. The methods that WRAP used to develop 
these emission inventories are described in more detail in the WRAP 
TSD. As explained in the WRAP TSD, emissions were calculated using best 
available data and approved EPA methods. See WRAP TSD section 3.
    Point sources in Oregon account for 39% (18,493 tons/year) of total 
State-wide SO2 emissions. The most significant point sources 
are coal-fired electrical generation units. Area sources (such as 
Pacific offshore shipping, wood combustion, and natural gas combustion) 
contribute about 21% (9,932 tons/year) to Oregon statewide 
SO2 emissions. On-road mobile and off-road mobile sources 
contribute a combined total of 21% (9,981 tons/year) of the Oregon 
SO2 emissions. In the Oregon Regional Haze SIP submittal, 
the State projected SO2 reductions of 57% in point sources, 
15% in area sources, 94% combined reduction in on-road and off-road 
mobile source emissions, and 17% in anthropogenic fire emissions by 
2018 (see Chapter 8 of the Oregon Regional Haze Plan).
    Upon further review, EPA determined that the 57% reduction in point 
source emissions was partially based on WRAP's assumption of an 
SO2 emission rate of 0.15 lb/mmBtu (presumptive limit for 
utility boilers identified in the BART Guidelines, see Section IV. 
E.4.) from the PGE Boardman coal fired power plant by 2018. The 
remaining SO2 point emission reductions in Oregon would be 
achieved through ongoing and new industrial control requirements, and 
projected source retirements and shutdowns. However, the BART 
determination for PGE Boardman based on a 2020 plant lifetime, which 
EPA proposes to approve in this rulemaking (see section III. E.4 
below), achieves an SO2 emission limit of 0.30 lb/mmBtu by 
2018, or about 4,000 ton/year less SO2 reductions than 
assumed by WRAP. Thus, statewide point source emission reductions of 
SO2 are estimated by EPA to be 35% by 2018. However, if PGE 
Boardman ceases to burn coal by 2020, as it would under the proposed 
approved BART determination, there will be an estimated 76% reduction 
is SO2 from point sources by 2020 which will provide a 
substantial improvement at that time in visibility in all 14 Class I 
areas currently impacted by PGE Boardman.
    On-road mobile sources account for 43% (111,646 tons/year) of the 
total NOX statewide emissions in Oregon. Off-road mobile 
sources account for 21% (53,896 tons/year), natural fire accounts for 
11% (27,397 tons/year), and point sources account for 10% (26,160 tons/
year) of the statewide NOX emissions. The State expects on-
road and off-road mobile source emissions to decline by 62% and 40%, 
respectively, by 2018, due to Federally mandated emission standards for 
mobile sources. The State also projects NOX emissions from 
point sources will decrease by 5% (or 1,213 tons/year). After 
evaluating the assumptions on which this 5% reduction was based, it 
appears that the 5% reduction does not include presumptive 
NOX emission reductions from the PGE Boardman facility by 
2018. The presumptive NOX emission limit for utility 
boilers, like PGE Boardman boiler, is 0.23 lb/mmBtu. EPA BART 
Guidelines (Section IV (E)(5)). The current NOX emission 
limit for the PGE Boardman is 0.43 lb/mmBtu, which results in emissions 
of about 10,300 tons/year (based on 2007 actual emissions). The BART 
determination for PGE Boardman based on it ceasing to burn coal by 
2020, which EPA proposes to approve in this rulemaking (see section 
III. E.4 below), achieves a NOX emission limit of 0.23 lb/
mmBtu, or annual emissions of about 5,500 tons/year (a 47% reduction) 
by 2013. Thus, in EPA's estimation, there will be about a 23% reduction 
in NOX emissions from all Oregon point sources by 2018. The 
State expects emissions from natural fire to remain unchanged by 2018. 
The net effect of these projected emissions results in a 37% overall 
reduction in NOX emissions in Oregon by 2018.
    Most of the organic carbon emissions in Oregon are from natural 
fire, which fluctuate greatly from year to year. For 2002, about 68% of 
statewide organic carbon emissions in Oregon were due to natural fire. 
Anthropogenic fire

[[Page 12657]]

(prescribed fire, agricultural field burning, and outdoor residential 
burning) accounts for 9% of the statewide organic carbon emissions. A 
variety of other area sources contribute a total of 19% of the 
statewide organic carbon, with residential wood combustion being a 
significant component. The State expects area source emissions to 
increase slightly (7%) by 2018, due mostly to population increases. The 
State projects the most significant reductions in organic carbon by 
2018 will be from point sources (80%) due to anticipated emission 
controls, off-road mobile (36%) due to implementation of the Federal 
mobile source regulations, and anthropogenic fire (28%) due to stricter 
Oregon rules controlling prescribed burning, agricultural burning, and 
residential burning. However, because natural fire emissions are 
expected to remain unchanged, total organic carbon emissions are 
estimated to decline by only 3% by 2018.
    Elemental carbon is associated with incomplete combustion. Like 
organic carbon, the primary source of elemental carbon in Oregon is 
natural fire (61%), area sources (such as wood combustion) (15%), and 
off-road mobile sources (12%). The State projects an increase of 
elemental carbon area source emissions by 6% due to population growth. 
Oregon estimates a decrease of combined on-road and off-road mobile 
source elemental carbon by about 65% by 2018. This reduction in mobile 
source emissions results from new Federal mobile source emission 
regulations. However, because elemental carbon emissions are dominated 
by natural fire, which are expected to remain unchanged, the State 
projects only an 11% reduction in State wide elemental carbon emissions 
by 2018.
    Other fine particulates, particles with an aerodynamic diameter of 
less than 2.5 micrometers (PM2.5), are emitted directly from 
a variety of area sources. Area sources are responsible for 34% of all 
directly-emitted PM2.5 emissions in Oregon. Wind-blown dust 
from agriculture, mining, construction, and roads contribute about 25% 
to the total statewide PM2.5 emissions. The State projects a 
12% increase in area source emissions due to population and economic 
growth, and wind-blown dust emissions to remain unchanged by 2018, 
resulting in a statewide 2% reduction in total PM2.5 by 
2018.
    Coarse particulate matter (PM coarse) is particulate matter within 
the size range of 2.5-10 micrometers. PM coarse emission sources 
include windblown dust, rock crushing and processing, material 
transfer, and open pit mining. Windblown dust is the dominant source of 
PM coarse emissions in Oregon at 104,274 tons/year (60%). Statewide PM 
coarse emissions are estimated to increase by 17% in 2018, primarily 
because emissions from fugitive dust sources (construction, paved 
roads, and unpaved roads) are expected to increase 106% due to 
population growth, and windblown dust will remain unchanged.
    Volatile organic compound (VOC) emissions are dominated by biogenic 
emissions from forests and vegetation, which account for about 70% of 
statewide Oregon VOC emissions. In Oregon, agricultural crops and urban 
vegetation are also significant sources. Other sources of VOCs are 
mobile sources at 8%, and area sources (industrial and commercial 
facilities, and residential solvent use) at 15%. Oregon projects that 
statewide area source emissions will increase by 36% by 2018, primarily 
due to population growth. As a result, the State estimates that total 
Oregon VOC emissions will increase by 2% by 2018.
    Ammonia (NH3) does not directly impair visibility but 
can be a precursor to the formation of particulate in the atmosphere 
through chemical reaction with SO2 and NOX to 
form ``secondary aerosol'' sulfate and nitrate. About 80% of the 
NH3 emissions in Oregon come from agricultural-related 
activities, primarily livestock operations and farm fertilizer 
applications. Since the NH3 emissions from these 
agricultural sources are expected to remain unchanged by 2018, and 
mobile source emissions of NH3 are projected to increase by 
45% (1,463 tons/year) by 2018, Oregon projects that there will be a 
total 2% increase of NH3 emissions by 2018.

D. Sources of Visibility Impairment in Oregon Class I Areas

    Each pollutant species has its own visibility impairing property; 1 
[mu]g/m\3\ of sulfate at high humidity, for example, is more effective 
in scattering light than 1 [mu]g/m\3\ of organic carbon and therefore 
impairs visibility more than organic carbon. Following the approach 
recommended by the WRAP, and as explained more fully below, Oregon used 
a two step process to identify the contribution of each source or 
source category to existing visibility impairment. First, ambient 
pollutant concentration by species (such as sulfate, nitrate, organic 
carbon, and elemental carbon) was determined from the IMPROVE data 
collected for each group of Class I areas. These concentrations were 
then converted into deciview values to distribute existing impairment 
among the measured pollutant species. The deciview value for each 
pollutant species was calculated by using the ``revised IMPROVE 
equation'' (See Section 2.C of the WRAP TSD) to calculate extinction 
from each pollutant species concentration. Extinction, in inverse 
megameters, was then converted to deciview using the equation defining 
deciview. Second, the Comprehensive Air Quality Model with Extensions 
(CAMx) and PM Source Apportionment Technology (PSAT) models were used 
to determine which sources and source categories contributed to the 
ambient concentration of each pollutant species. Thus, impairment was 
distributed by source and source category.
    After considering the available models, the WRAP and Western States 
selected two source apportionment analysis tools. The first source 
apportionment tool was the Comprehensive Air Quality Model with 
Extensions (CAMx) in conjunction with PM Source Apportionment 
Technology (PSAT). This model uses emission source characterization, 
meteorology and atmospheric chemistry for aerosol formation to predict 
pollutant concentrations in the Class I area. The predicted results are 
compared to measured concentrations to assess accuracy of model output. 
CAMx PSAT modeling was used to determine source contribution to ambient 
sulfate and nitrate concentrations. The WRAP used state-of-the-science 
source apportionment tools within a widely used photochemical model. 
EPA has reviewed the PSAT analysis and considers the modeling, 
methodology, and analysis acceptable. See section 6.A of the WRAP TSD.
    The second tool was the Weighted Emissions Potential (WEP) model, 
used primarily as a screening tool to decide which geographic source 
regions have the potential to contribute to haze at specific Class I 
areas. WEP does not account for atmospheric chemistry (secondary 
aerosol formation) or removal processes, and thus is used for 
estimating inert particulate concentrations. The model uses back 
trajectory wind flow calculations and resident time of an air parcel to 
determine source and source category and location for ambient organic 
carbon, elemental carbon, PM2.5, and coarse PM 
concentrations. These modeling tools were the state-of-the-science and 
EPA has determined that these tools were appropriately used by WRAP for 
regional haze planning. Description of these tools and our evaluation 
of them

[[Page 12658]]

are described in more detail in section 6 of the WRAP TSD.
    Section 9.2.1 of the Oregon SIP submittal explains that sources in 
areas outside of the modeling domain (i.e., portions of northern 
Canada, southern Mexico, Pacific offshore, and global sources) 
contribute between 40% to 60% of the sulfate that impairs visibility in 
all of Oregon's Class I areas on the 20% worst days. SO2 
sources within the WRAP region contribute about 33% of sulfate that 
impairs visibility in Oregon Class I areas. Of the SO2 
contribution from WRAP States, about 50% of the SO2 comes 
from point, area, and mobile sources in Oregon.
    The PSAT results also show that between 15 to 33% of the nitrate 
impairing visibility in all of Oregon's Class I areas comes from 
sources outside of the modeling domain, with the remainder from sources 
within the WRAP region.
North and Central Cascades Class I Areas
    The PSAT results for sulfate show that for the 20% worst days 
during 2000-2004 the North and Central Cascades Class I areas are 
mostly impacted by sulfate from a combination of SO2 point, 
area and mobile sources in Washington, Oregon, and marine shipping in 
the Pacific offshore region (see Oregon Regional Haze SIP submittal 
Figures 9.2.1-1 through Figures 9.2.1-6). The mobile source 
contribution to sulfate pollution is expected to decline significantly 
by 2018 due to the implementation of the Federal low sulfur diesel fuel 
rule, which went into effect in 2006 for on-road mobile sources, and 
took effect for non-road mobile sources in 2010.
    The PSAT results for nitrate show that a majority of the nitrate 
impacting the North and Central Cascades Class I areas is from mobile 
sources in Oregon and Washington (see Oregon Regional Haze SIP 
submittal Figures 9.2.2-1 through Figures 9.2.2-6). PSAT results 
predict about a 50% reduction in nitrate concentrations in these area 
by 2018 due to a 50% reduction in NOX emissions from Oregon 
and Washington mobile sources.
    Based on the WEP model results, the organic carbon in the North 
Cascades on the 20% worst visibility days comes mostly from area 
sources and natural fires in Oregon, with a small contribution from 
areas sources in Washington. On the 20% worst visibility days at North 
Cascades, most of the primary PM2.5 contributions come from 
area and fugitive dust sources in Oregon, and to a lesser extent area 
and point sources in Washington.
    For the 20% worst visibility days in the Central Cascades, most of 
the organic carbon comes from a combination of area source emissions 
and natural and anthropogenic fire in Oregon. For the 20% worst 
visibility days in the Central Cascades, the OC comes primarily from 
Oregon area sources. For the 20% worst visibility days in the Central 
Cascades, most of the PM2.5 comes from area sources in 
Oregon.
Southern Cascades Class I Areas
    For the 20% worst days in the three Class I areas in the Southern 
Cascades, overall visibility impairment due to sulfate are lower 
compared to the Northern and Central Cascade Class I areas. Most of the 
sulfate impacting these Southern Cascade Class I areas is from point 
sources in Oregon, Washington, California, and Canada. Pacific offshore 
shipping is also a substantial contributor of sulfate to this area.
    For the 20% worst days in Southern Cascades, the most significant 
sources of nitrate are mobile sources in Oregon and Washington. The 
impact from these sources is expected to decrease by about 50% by 2018 
due to Federal mobile source emission control measures.
    For the 20% worst visibility days in the Southern Cascades, 
approximately 90% of the organic carbon contribution came from natural 
fires in 2002. Emissions from natural fires are expected to be 
unchanged by 2018.
Coast Range Class I Area
    The only Class I area in the Coast Range group is the Kalmiopsis 
Wilderness Area. The most significant sources of sulfate to the 
Kalmiopsis Wilderness Area are natural fires in Oregon, and marine 
shipping in the Pacific Ocean. Both of these sources are expected to be 
unchanged by 2018.
    A majority of the nitrate impacting the Kalmiopsis Wilderness Area 
is from mobile sources in Oregon and from marine shipping in the 
Pacific Ocean. Smaller contributions come from Washington and 
California mobile sources. Mobile source contributions to this area are 
expected to decrease by about 50% by 2018.
    For the 20% worst visibility days in the Kalmiopsis Wilderness, 
almost all of organic carbon for the 2002 base year came from natural 
fire. For the 20% worst visibility days in the Kalmiopsis, the 
PM2.5 contributions were mostly from natural fire in Oregon.
    For the 20% worst days in the Kalmiopsis Wilderness Area, the 
contribution from point sources is relatively small. For the 20% of 
worst days in the Kalmiopsis Wilderness Area, the vast majority of 
nitrate comes from Oregon mobile sources, with smaller contributions 
from Washington and California mobile sources. There is also a 
substantial nitrate contribution from Pacific offshore shipping, due 
primarily to the close proximity of the Kalmiopsis Wilderness Area to 
the Pacific Ocean.
Eastern Oregon Class I Areas
    For the 20% worst days in Strawberry Mountain Wilderness and Eagle 
Cap Wilderness Areas, the contribution of sulfates from each 
geographical area is relatively low (less than 0.12 micrograms per 
cubic meter), with the largest contribution being from point sources 
from Canada, Washington, and Oregon. However, the visibility on the 20% 
worst days in this area is significantly impacted (greater than 0.20 
micrograms per cubic meter) by a combination of point, area, and mobile 
NOX sources in Oregon, Washington, and Idaho.
    For the 20% worst visibility days in the Strawberry Mountain 
Wilderness and Eagle Cap Wilderness Areas, about 80% of the organic 
carbon contribution came from a combination of natural fires and 
anthropogenic sources in Oregon. For the 20% worst visibility days 
there is also a dominant PM2.5 contribution from windblown 
dust, and some fugitive and road dust area and fire sources in Oregon. 
The contribution of this mixture of source from Washington is about 
half of the Oregon level.
Eastern Oregon/Western Idaho Class I Area
    For the 20% worst days in the Hells Canyon Wilderness Area, the 
contribution of sulfates from each geographical area is relatively low 
(less than 0.06 micrograms per cubic meter), with the largest 
contribution being from point sources from Canada, Idaho, and Oregon. 
However, the visibility on the 20% worst days in this area is 
significantly impacted (greater than 0.35 micrograms per cubic meter) 
by a combination of mobile and area NOX sources in Idaho, 
and to a lesser degree, point and mobile sources in Oregon.
    For the 20% worst visibility days in the Hells Canyon Wilderness 
Area, the majority of the organic carbon contribution comes from a 
combination of Oregon natural and anthropogenic fire sources and to a 
lesser extent from anthropogenic and natural fire sources in Oregon. 
For the 20% worst visibility days in the Hells Canyon Wilderness Area, 
most of the contribution of PM2.5 comes from a combination 
of windblown, fugitive and road dust

[[Page 12659]]

sources in Idaho and to a lesser degree, the same mix of sources in 
Oregon.
    EPA is proposing to find that Oregon has appropriately identified 
the primary pollutants impacting its Class I areas. EPA is also 
proposing to find that the SIP contains an appropriate analysis of the 
impact of these pollutants in nearby Class I areas.

E. Best Available Retrofit Technology (BART)

1. BART-Eligible Sources in Oregon
    The first step of a BART evaluation is to identify all the BART-
eligible sources within the State's boundaries. Table 10.2-1 in the 
Oregon Regional Haze SIP submittal presents the list of ten BART-
eligible sources located in Oregon. These sources are: Amalgamated 
Sugar (Nyssa), Portland Gas and Electric (PGE) power plant (Boardman), 
Boise Paper Solutions (St. Helens), Georgia Pacific Wauna pulp mill 
(Clatskanie), PGE Beaver power plant (Clatskanie), Georgia Pacific pulp 
mill (Toledo), Pope and Talbot pulp mills (Halsey), SP Newsprint 
(Newberg), International Paper pulp mill (Springfield), and Kingsford 
charcoal production (Springfield).
2. BART-Subject Sources in Oregon
    The second step of a BART evaluation is to identify those BART-
eligible sources that may reasonably be anticipated to cause or 
contribute to any impairment of visibility at any Class I area and are, 
therefore, subject to BART. As explained above, EPA has issued 
guidelines that provide States with guidance for addressing the BART 
requirements. 40 CFR Part 51 Appendix Y--Guidelines for BART 
determinations under the regional Haze Rule (BART Guidelines); see also 
70 FR 39104 (July 6, 2005). The BART Guidelines describe how States may 
consider exempting some BART-eligible sources from further BART review 
based on dispersion modeling showing that the source contributes to 
impairment below a certain threshold amount. Oregon conducted 
dispersion modeling for the BART-eligible sources to determine the 
visibility impacts of these sources on Class I areas.
    The BART Guidelines require States to set a contribution threshold 
to assess whether the impact of a single source is sufficient to cause 
or contribute to visibility impairment at a Class I area. Generally, 
States may not establish a contribution threshold that exceeds 0.5 dv 
impact. 70 FR at 39161. Oregon established a contribution threshold of 
0.5 dv through negotiated rulemaking with industry, FLMs, and the 
public. In its SIP submittal, Oregon notes that the 0.5 dv threshold is 
also consistent with the threshold used by all other States in the 
WRAP. Any source with an impact of greater than 0.5 dv in any Class I 
area, including Class I areas in other States, would be subject to a 
BART analysis and BART emission limitations.
    Oregon established a contribution threshold of 0.5 dv based on the 
following reasons; (1) it equates to the 5% extinction threshold for 
new sources under the PSD New Source Review rules, (2) it is consistent 
with the threshold selected by other States in the West, (3) it 
represents the limit of perceptible change, and (4) there was no clear 
rationale or justification for selecting a lower level. EPA finds that 
these reasons alone do not provide sufficient basis for concluding that 
such a threshold is appropriate for Oregon. Nevertheless, based on the 
additional information described below, EPA proposes to approve the 
list of subject-to-BART sources in this SIP submittal.
    In the BART Guidelines, EPA recommended that States ``consider the 
number of BART sources affecting the Class I areas at issue and