[Federal Register Volume 77, Number 107 (Monday, June 4, 2012)]
[Proposed Rules]
[Pages 33022-33062]
[FR Doc No: 2012-12923]

Vol. 77

Monday,

No. 107

June 4, 2012

Part II

Environmental Protection Agency

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40 CFR Part 52

Approval, Disapproval and Promulgation of Implementation Plans; State
of Wyoming; Regional Haze State Implementation Plan; Federal
Implementation Plan for Regional Haze; Proposed Rule

Federal Register / Vol. 77, No. 107 / Monday, June 4, 2012 / Proposed
Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2012-0026, FRL-9678-9]

Approval, Disapproval and Promulgation of Implementation Plans;
State of Wyoming; Regional Haze State Implementation Plan; Federal
Implementation Plan for Regional Haze

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to partially approve and partially disapprove
approve a State Implementation Plan (SIP) revision submitted by the
State of Wyoming on January 12, 2011, that addresses regional haze.
This SIP revision was submitted to address the requirements of the
Clean Air Act (CAA or ``the Act'') and our rules that require states to
prevent any future and remedy any existing anthropogenic impairment of
visibility in mandatory Class I areas caused by emissions of air
pollutants from numerous sources located over a wide geographic area
(also referred to as the ``regional haze program''). States are
required to assure reasonable progress toward the national goal of
achieving natural visibility conditions in Class I areas. EPA is taking
this action pursuant to section 110 of the CAA.
    EPA is proposing a Federal Implementation Plan (FIP) to address the
deficiencies identified in our proposed partial disapproval of
Wyoming's regional haze SIP. In lieu of this proposed FIP, or a portion
thereof, we propose approval of a SIP revision if the State submits
such a revision and the revision matches the terms of our proposed FIP.

DATES: Comments: Written comments must be received at the address below
on or before August 3, 2012. Public Hearings: A public hearing for this
proposal is scheduled to be held on Tuesday, June 26, 2012, at the
Hershchler Building, Room B-63, 122 W. 25th St., Cheyenne, Wyoming
82002. Another public hearing is scheduled to be held on Thursday, June
28, 2012, at Western Wyoming Community College, Room 1005, 2500 College
Drive, Rock Springs, Wyoming 82901. The public hearings will be held
from 1 p.m. until 5 p.m., and again from 6 p.m. until 8 p.m.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2012-0026, by one of the following methods:
     http://www.regulations.gov. Follow the on-line
instructions for submitting comments.
     Email<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER> (please alert the individual listed in
the FOR FURTHER INFORMATION CONTACT if you are faxing comments).
     Mail: Carl Daly, Director, Air Program, Environmental
Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street,
Denver, Colorado 80202-1129.
     Hand Delivery: Carl Daly, Director, Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. Such deliveries are only accepted
Monday through Friday, 8 a.m. to 4:30 p.m., excluding Federal holidays.
Special arrangements should be made for deliveries of boxed
information.
    Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2012-0026. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://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 http://www.regulations.gov or email. The http://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 email comment directly to EPA, without
going through http://www.regulations.gov, your email 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 instructions on submitting
comments, go to Section I. General Information of the SUPPLEMENTARY
INFORMATION section of this document.
    Docket: All documents in the docket are listed in the http://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 http://www.regulations.gov or in hard copy at the Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. EPA requests that if at all
possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8 a.m. to 4
p.m., excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT: Laurel Dygowski, Air Program, U.S.
Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129,<PHONE_NUMBER>,
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Definitions

    For the purpose of this document, we are giving meaning to certain
words or initials as follows:

    i. The words or initials Act or CAA mean or refer to the Clean
Air Act, unless the context indicates otherwise.
    ii. The initials AFRC mean or refer to air-fuel ratio controls.
    iii. The initials BART mean or refer to Best Available Retrofit
Technology.
    iv. The initials CAMx mean or refer to Comprehensive Air Quality
Model.
    v. The initials CMAQ mean or refer to Community Multi-Scale Air
Quality modeling system.
    vi. The initials CEMS mean or refer to continuous emission
monitoring systems.
    vii. The initials EC mean or refer to elemental carbon.
    viii. The initials EGUs mean or refer to Electric Generating
Units.
    ix. The initials EGR mean or refer to exhaust gas recirculation.
    x. The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
    xi. The initials ESP mean or refer to electrostatic
precipitator.
    xii. The initials FGC mean or refer to flue gas conditioning.
    xiii. The initials FGD mean or refer to flue gas
desulfurization.
    xiv. The initials FGR mean or refer to external flue gas
recirculation.
    xv. The initials FIP mean or refer to Federal Implementation
Plan.
    xvi. The initials FLMs mean or refer to Federal Land Managers.

    xvii. The initials FS mean or refer to the U.S. Forest Service.
    xviii. The initials IMPROVE mean or refer to Interagency
Monitoring of Protected Visual Environments monitoring network.
    xix. The initials IWAQM mean or refer to Interagency Workgroup
on Air Quality Modeling.
    xx. The initials LEC mean or refer to low-emission combustion.
    xxi. The initials LNB mean or refer to low NOX
burner.
    xxii. The initials LTS mean or refer to the long-term strategy.
    xxiii. The initials MW mean or refer to megawatts.
    xxiv. The initials NH3 mean or refer to ammonia.
    xxv. The initials NOX mean or refer to nitrogen oxides.
    xxvi. The initials NPS mean or refer to National Park Service.
    xxvii. The initials OC mean or refer to organic carbon.
    xxviii. The initials OFA mean or refer to overfire air.
    xxix. The initials PM2.5 mean or refer to particulate matter
with an aerodynamic diameter of less than 2.5 micrometers.
    xxx. The initials PM10 mean or refer to particulate matter with
an aerodynamic diameter of less than 10 micrometers.
    xxxi. The initials PSAT mean or refer to Particle Source
Apportionment Technology.
    xxxii. The initials PSD mean or refer to Prevention of
Signification Deterioration.
    xxxiii. The initials RAVI mean or refer to Reasonably
Attributable Visibility Impairment.
    xxxiv. The initials RHR mean or refer to the Regional Haze Rule.
    xxxv. The initials RMC mean or refer to the Regional Modeling
Center at the University of California Riverside.
    xxxvi. The initials RPGs mean or refer to Reasonable Progress
Goals.
    xxxvii. The initials RPOs mean or refer to regional planning
organizations.
    xxxviii. The initials SCR mean or refer to selective catalytic
reduction.
    xxxix. The initials SIP mean or refer to State Implementation
Plan.
    xl. The initials SNCR mean or refer to selective non-catalytic
reduction.
    xli. The initials SO2 mean or refer to sulfur dioxide.
    xlii. The initials SOFA mean or refer to separated overfire air.
    xliii. The initials TSD mean or refer to Technical Support
Document.
    xliv. The initials ULNB mean or refer to ultra-low
NOX burners.
    xlv. The initials URP mean or refer to Uniform Rate of Progress.
    xlvi. The initials VOC mean or refer to volatile organic
compounds.
    xlvii. The initials WAQSR mean or refer to Wyoming Air Quality
Standards and Regulations.
    xlviii. The initials WEP mean or refer to Weighted Emissions
Potential.
    xlix. The initials WRAP mean or refer to the Western Regional
Air Partnership.
    l. The words Wyoming and State mean the State of Wyoming.

Table of Contents

I. General Information
    A. What should I consider as I prepare my comments for EPA?
II. Overview of Proposed Actions
III. SIP and FIP Background
IV. Background
    A. Regional Haze
    B. Requirements of the CAA and EPA's Regional Haze Rule (RHR)
    C. Roles of Agencies in Addressing Regional Haze
V. Requirements for the Regional Haze SIPs
    A. The CAA and the Regional Haze Rule
    B. Determination of Baseline, Natural, and Current Visibility
Conditions
    C. Determination of Reasonable Progress Goals
    D. Best Available Retrofit Technology
    E. Long-Term Strategy
    F. Coordinating Regional Haze and Reasonably Attributable
Visibility Impairment
    G. Monitoring Strategy and Other Implementation Plan
Requirements
    H. Consultation With States and Federal Land Managers (FLMs)
VI. EPA's Evaluation of Wyoming's Regional Haze SIP
    A. Affected Class I Areas
    B. Baseline Visibility, Natural Visibility, and Uniform Rate of
Progress
    C. BART Determinations
    1. BART-Eligible Sources
    2. Sources Subject-to-BART
    a. Modeling Methodology
    b. Contribution Threshold
    c. Sources Identified by Wyoming as Subject-to-BART
    3. BART Determinations and Federally Enforceable Limits
    a. Visibility Improvement Modeling
    b. Summary of BART Determinations and Federally Enforceable
Limits
    i. FMC Westvaco--Units NS-1A and NS-1B
    ii. General Chemical Green River--Boilers C and D
    iii. Basin Electric Laramie River Station--Units 1-3
    iv. PacifiCorp Dave Johnston--Units 3 and 4
    v. PacifiCorp Jim Bridger Units 1-4
    vi. PacifiCorp Naughton Units 1-3
    vii. PacifiCorp Wyodak--Unit 1
    D. Reasonable Progress Requirements
    1. Visibility Impairing Pollutants and Sources
    2. Four-Factor Analyses
    a. Stationary Sources
    b. Summary of Reasonable Progress Determinations and Limits
    i. Oil and Gas Area Sources
    ii. Mountain Cement Company Laramie Plant--Kiln
    3. Reasonable Progress Goals
    E. Long Term Strategy
    1. Emission Inventories
    2. Consultation and Emissions Reductions for Other States' Class
I Areas
    3. Mandatory Long-Term Strategy Requirements
    a. Reductions Due to Ongoing Air Pollution Programs
    b. Measures to Mitigate the Impacts of Construction Activities
    c. Smoke Management
    d. Emission Limitations and Schedules for Compliance
    e. Source Retirement and Replacement Schedules
    f. Enforceability of Wyoming's Measures
    g. Anticipated Net Effect on Visibility Due to Projected Changes
    4. Our Conclusions on Wyoming's Long-Term Strategy
    F. Coordination of RAVI and Regional Haze Rule Requirements
    G. Monitoring Strategy and Other Implementation Plan
Requirements
    H. Consultation With FLMs
    I. Periodic SIP Revisions and 5-Year Progress Reports
VII. Federal Implementation Plan
    A. Disapproval of the State's NOX BART Determinations
and Federal Implementation Plan for NOX BART
Determinations and Limits
    1. Disapproval of the State's Basin Electric Laramie River Units
1-3 NOX BART Determination and FIP to Address
NOX BART
    2. Disapproval of the State's PacifiCorp Dave Johnston Unit 3
NOX BART Determination and FIP to Address NOX
BART
    3. Disapproval of the State's PacifiCorp Jim Bridger Unit 1 and
2 NOX BART Determination and FIP to Address
NOX BART
    4. Proposals in the Alternative for PacifiCorp Jim Bridger Units
1, 2, 3, and 4 NOX BART
    5. Disapproval of the State's PacifiCorp Wyodak Unit 1
NOX BART Determination and FIP to Address NOX
BART
    B. Disapproval of the State's NOX Reasonable Progress
Determinations and Federal Implementation Plan for NOX
Reasonable Progress Determinations and Limits
    1. PacifiCorp Dave Johnston--Units 1 and 2
    C. Reasonable Progress Goals
    D. Federal Monitoring, Recordkeeping, and Reporting Requirements
    E. Federal Implementation Plan for the Long-Term Strategy
    F. Federal Implementation Plan for Coordination of RAVI and
Regional Haze Long-Term Strategy
VIII. EPA's Proposed Action
IX. Statutory and Executive Order Reviews

I. General Information

A. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit CBI to EPA through http://www.regulations.gov or email. 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:
    a. Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).
    b. 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.
    c. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
    d. Describe any assumptions and provide any technical information
and/or data that you used.
    e. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
    f. Provide specific examples to illustrate your concerns, and
suggest alternatives.
    g. Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
    h. Make sure to submit your comments by the comment period deadline
identified.

II. Overview of Proposed Actions

    EPA is proposing to partially approve and partially disapprove a
regional haze SIP revision submitted by the State of Wyoming on January
12, 2011. Specifically, we are proposing to disapprove the following:
     The State's nitrogen oxides (NOX) best
available retrofit technology (BART) determinations for PacifiCorp Dave
Johnston Unit 3, PacifiCorp Jim Bridger Units 1 and 2, PacifiCorp
Wyodak Unit 1, and Basin Electric Laramie River Units 1, 2, and 3.
     The State's NOX reasonable progress
determination for PacifiCorp Dave Johnston Units 1 and 2.
     Wyoming's Reasonable Progress Goals (RPGs).
     The State's monitoring, recordkeeping, and reporting
requirements in Chapter 6.4 of the SIP.
     Portions of the State's long-term strategy (LTS) that rely
on or reflect other aspects of the regional haze SIP.
     The State's SIP because it does not contain the necessary
provisions to meet the requirements for the coordination of the review
of the reasonably attributable visibility impairment (RAVI) and the
regional haze LTS.
    We are proposing to approve the remaining aspects of the State's
January 12, 2011, SIP submittal. We are also seeking comment on two
alternative proposals related to the State's NOX BART
determination for PacifiCorp Jim Bridger Units 1 and 2.
    We are proposing the promulgation of a FIP to address the
deficiencies in the Wyoming regional haze SIP that we have identified
in this proposal. The proposed FIP includes the following elements:
     NOX BART determinations and limits for
PacifiCorp Dave Johnston Unit 3, PacifiCorp Jim Bridger Units 1 and 2,
PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River Units 1, 2,
and 3.
     NOX reasonable progress determination and
limits for PacifiCorp Dave Johnston Units 1 and 2.
     RPGs consistent with the SIP limits proposed for approval
and the proposed FIP limits.
     Monitoring, recordkeeping, and reporting requirements
applicable to all BART and reasonable progress sources for which there
is a SIP or FIP emissions limit.
     LTS elements pertaining to emission limits and compliance
schedules for the proposed BART and reasonable progress FIP emission
limits.
     Provisions to ensure the coordination of the RAVI and
regional haze LTS.
    In lieu of our proposed FIP, or a portion thereof, we would propose
approval of a SIP revision if the State submits such a revision and the
revision matches the terms of our proposed FIP. We encourage the State
to submit a SIP revision to replace the FIP, either before or after our
final action.

III. SIP and FIP Background

    The CAA requires each state to develop plans to meet various air
quality requirements, including protection of visibility. CAA sections
110(a), 169A, and 169B. The plans developed by a state are referred to
as SIPs. A state must submit its SIPs and SIP revisions to us for
approval. Once approved, a SIP is enforceable by EPA and citizens under
the CAA, also known as being federally enforceable. If a state fails to
make a required SIP submittal or if we find that a state's required
submittal is incomplete or unapprovable, then we must promulgate a FIP
to fill this regulatory gap. CAA section 110(c)(1). As discussed
elsewhere in this notice, we are proposing to disapprove aspects of
Wyoming's regional haze SIP. We are proposing FIPs to address the
deficiencies in Wyoming's regional haze SIP.

IV. Background

A. Regional Haze

    Regional haze is visibility impairment that is produced by a
multitude of sources and activities which are located across a broad
geographic area and emit fine particles (PM2.5) (e.g.,
sulfates, nitrates, organic carbon (OC), elemental carbon (EC), and
soil dust), and their precursors (e.g., sulfur dioxide
(SO2), NOX, and in some cases, ammonia
(NH3) and volatile organic compounds (VOC)). Fine particle
precursors react in the atmosphere to form PM2.5, which
impairs visibility by scattering and absorbing light. Visibility
impairment reduces the clarity, color, and visible distance that one
can see. PM2.5 can also cause serious health effects and
mortality in humans and contributes to environmental effects such as
acid deposition and eutrophication.
    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 park and
wilderness areas. The average visual range \1\ in many Class I areas
(i.e., national parks and memorial parks, wilderness areas, and
international parks meeting certain size criteria) in the western
United States is 100-150 kilometers, or about one-half to two-thirds of
the visual range that would exist without anthropogenic air pollution.
In most of the eastern Class I areas of the United States, the average
visual range is less than 30 kilometers, or about one-fifth of the
visual range that would exist under estimated natural conditions. 64 FR
35715 (July 1, 1999).
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    \1\ Visual range is the greatest distance, in kilometers or
miles, at which a dark object can be viewed against the sky.
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B. Requirements of the CAA and EPA's Regional Haze Rule (RHR)

    In section 169A of the 1977 Amendments to the CAA, 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 mandatory Class I Federal areas \2\ which
impairment

results from manmade air pollution.'' 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.'' 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.
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    \2\ 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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    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 35714 (July 1, 1999), codified at 40 CFR part 51, subpart
P. 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 preamble. The
requirement to submit a regional haze SIP applies to all 50 states, the
District of Columbia and the Virgin Islands. 40 CFR 51.308(b) requires
states to submit the first implementation plan addressing regional haze
visibility impairment no later than December 17, 2007.\3\
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    \3\ EPA's regional haze regulations require subsequent updates
to the regional haze SIPs. 40 CFR 51.308(g)-(i).
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    Few states submitted a regional haze SIP prior to the December 17,
2007 deadline, and on January 15, 2009, EPA found that 37 states
(including Colorado), the District of Columbia, and the Virgin Islands,
had failed to submit SIPs addressing the regional haze requirements. 74
FR 2392. Once EPA has found that a state has failed to make a required
submission, EPA is required to promulgate a FIP within two years unless
the state submits a SIP and the Agency approves it within the two-year
period. CAA Sec.  110(c)(1).

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 can originate
from sources located across broad geographic areas, EPA has encouraged
the states and tribes across the United States to address visibility
impairment from a regional perspective. Five regional planning
organizations (RPOs) were developed to address regional haze and
related issues. The RPOs first evaluated technical information to
better understand how their states and tribes impact Class I areas
across the country, and then pursued the development of regional
strategies to reduce emissions of particulate matter (PM) and other
pollutants leading to regional haze.
    The Western Regional Air Partnership (WRAP) RPO is a collaborative
effort of state governments, tribal governments, and various federal
agencies established to initiate and coordinate activities associated
with the management of regional haze, visibility and other air quality
issues in the western United States. WRAP member state governments
include: Alaska, Arizona, California, Colorado, Idaho, Montana, New
Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and
Wyoming. 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.

V. Requirements for Regional Haze SIPs

    The following is a summary of the requirements of the RHR. See 40
CFR 51.308 for further detail regarding the requirements of the rule.

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
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 as the principal metric or unit
for expressing visibility. See 70 FR 39104, 39118. This visibility
metric expresses uniform changes in the degree of haze in terms of
common increments across the entire range of visibility conditions,
from pristine to extremely hazy conditions. Visibility expressed in
deciviews is determined by using air quality measurements to estimate
light extinction and then transforming the value of light extinction
using a logarithm function. The deciview is a more useful measure for
tracking progress in improving visibility than light extinction itself
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.\4\
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    \4\ The preamble to the RHR provides additional details about
the dv. 64 FR 35714, 35725 (July 1, 1999).
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    The deciview is used in expressing RPGs (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 anthropogenic 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
percent least impaired (``best'') and 20 percent 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. We have provided guidance to states regarding how
to calculate baseline, natural and current visibility conditions.\5\
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    \5\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, September 2003, EPA-454/B-03-005, available
at http://www.epa.gov/ttncaaa1/t1/memoranda/RegionalHaze_envcurhr_gd.pdf, (hereinafter referred to as ``our 2003 Natural Visibility
Guidance''); and Guidance for Tracking Progress Under the Regional
Haze Rule, September 2003, EPA-454/B-03-004, available at http://www.epa.gov/ttncaaa1/t1/memoranda/rh_tpurhr_gd.pdf, (hereinafter
referred to as our ``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
percent least impaired days and 20 percent 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 period is considered the time from which improvement in
visibility is measured.

C. Determination of Reasonable Progress Goals

    The vehicle for ensuring continuing progress towards achieving the
natural visibility goal is the submission of a series of regional haze
SIPs from the states that establish two RPGs (i.e., two distinct goals,
one for the ``best'' and one for the ``worst'' days) for every Class I
area for each (approximately) 10-year implementation period. See 40 CFR
51.308(d), (f). The RHR does not mandate specific milestones or rates
of progress, but instead calls for states to establish goals that
provide for ``reasonable progress'' toward achieving natural visibility
conditions. In setting RPGs, states must provide for an improvement in
visibility for the most impaired days over the (approximately) 10-year
period of the SIP, and ensure no degradation in visibility for the
least impaired days over the same period. Id.
    In establishing RPGs, states are required to consider the following
factors established in section 169A of the CAA and in our RHR at 40 CFR
51.308(d)(1)(i)(A): (1) The costs of compliance; (2) the time necessary
for compliance; (3) the energy and non-air quality environmental
impacts of compliance; and (4) the remaining useful life of any
potentially affected sources. States must demonstrate in their SIPs how
these factors are considered when selecting the RPGs for the best and
worst days for each applicable Class I area. In setting the RPGs,
states must also consider the rate of progress needed to reach natural
visibility conditions by 2064 (referred to as the ``uniform rate of
progress'' (URP) or the ``glidepath'') and the emission reduction
measures needed to achieve that rate of progress over the 10-year
period of the SIP. Uniform progress towards achievement of natural
conditions by the year 2064 represents a rate of progress, which states
are to use for analytical comparison to the amount of progress they
expect to achieve. In setting RPGs, each state with one or more Class I
areas (``Class I state'') must also consult with potentially
``contributing states,'' i.e., other nearby states with emission
sources that may be affecting visibility impairment at the state's
Class I areas. 40 CFR 51.308(d)(1)(iv). In determining whether a
state's goals for visibility improvement provide for reasonable
progress toward natural visibility conditions, EPA is required to
evaluate the demonstrations developed by the state pursuant to
paragraphs 40 CFR 51.308(d)(1)(i) and (d)(1)(ii). 40 CFR
51.308(d)(1)(iii).

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 \6\ built between 1962 and 1977 procure, install, and operate
the ``Best Available Retrofit Technology'' as determined by the state.
Under the RHR, states are directed to conduct BART determinations for
such ``BART-eligible'' 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.
---------------------------------------------------------------------------

    \6\ The set of ``major stationary sources'' potentially subject-
to-BART is listed in CAA section 169A(g)(7).
---------------------------------------------------------------------------

    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. 70 FR 39104. In making a BART determination for
a fossil fuel-fired electric generating plant with a total generating
capacity in excess of 750 megawatts (MW), 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. Regardless of source size or type, a state
must meet the requirements of the CAA and our regulations for selection
of BART, and the state's BART analysis and determination must be
reasonable in light of the overarching purpose of the regional haze
program.
    The process of establishing BART emission limitations can be
logically broken down into three steps: First, states identify those
sources which meet the definition of ``BART-eligible source'' set forth
in 40 CFR 51.301; \7\ second,

states determine which of such sources ``emits any air pollutant which
may reasonably be anticipated to cause or contribute to any impairment
of visibility in any such area'' (a source which fits this description
is ``subject to BART''); and third, for each source subject-to-BART,
states then identify the best available type and level of control for
reducing emissions.
---------------------------------------------------------------------------

    \7\ BART-eligible sources are those sources that have the
potential to emit 250 tons or more of a visibility-impairing air
pollutant, were not in operation prior to August 7, 1962, but were
in existence on August 7, 1977, and whose operations fall within one
or more of 26 specifically listed source categories. 40 CFR 51.301.
---------------------------------------------------------------------------

    States must address all visibility-impairing pollutants emitted by
a source in the BART determination process. The most significant
visibility impairing pollutants are SO2, NOX, and
PM. EPA has stated that states should use their best judgment in
determining whether VOC or NH3 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. Any
exemption threshold set by the state should not be higher than 0.5
deciview. 40 CFR part 51, appendix Y, section III.A.1.
    In their SIPs, states must identify the sources that are subject-
to-BART and document their BART control determination analyses for such
sources. In making their BART determinations, section 169A(g)(2) of the
CAA requires that states consider the following factors when evaluating
potential control technologies: (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.
    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 of EPA approval of the regional
haze SIP. CAA section 169(g)(4) and 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. See CAA section 110(a). As noted above, the RHR
allows states to implement an alternative program in lieu of BART so
long as the alternative program can be demonstrated to achieve greater
reasonable progress toward the national visibility goal than would
BART.

E. Long-Term Strategy

    Consistent with the requirement in section 169A(b) of the CAA that
states include in their regional haze SIP a 10 to 15 year strategy for
making reasonable progress, section 51.308(d)(3) of the RHR requires
that states include a LTS in their regional haze SIPs. The LTS is the
compilation of all control measures a state will use during the
implementation period of the specific SIP submittal to meet applicable
RPGs. The LTS must include ``enforceable emissions limitations,
compliance schedules, and other measures as necessary to achieve the
reasonable progress goals'' for all Class I areas within, or affected
by emissions from, the state. 40 CFR 51.308(d)(3).
    When a state's emissions are reasonably anticipated to cause or
contribute to visibility impairment in a Class I area located in
another state, the RHR requires the impacted state to coordinate with
the contributing states in order to develop coordinated emissions
management strategies. 40 CFR 51.308(d)(3)(i). In such cases, the
contributing state must demonstrate that it has included, in its SIP,
all measures necessary to obtain its share of the emission reductions
needed to meet the RPGs for the Class I area. Id. at (d)(3)(ii). The
RPOs have provided forums for significant interstate consultation, but
additional consultations between states may be required to sufficiently
address interstate visibility issues. This is especially true where two
states belong to different RPOs.
    States should consider all types of anthropogenic sources of
visibility impairment in developing their long-term strategy, including
stationary, minor, mobile, and area sources. At a minimum, states must
describe how each of the following seven factors listed below are taken
into account in developing their LTS: (1) Emission reductions due to
ongoing air pollution control programs, including measures to address
RAVI; (2) measures to mitigate the impacts of construction activities;
(3) emissions limitations and schedules for compliance to achieve the
RPG; (4) source retirement and replacement schedules; (5) smoke
management techniques for agricultural and forestry management purposes
including plans as currently exist within the state for these purposes;
(6) enforceability of emissions limitations and control measures; and
(7) the anticipated net effect on visibility due to projected changes
in point, area, and mobile source emissions over the period addressed
by the LTS. 40 CFR 51.308(d)(3)(v).

F. Coordinating Regional Haze and Reasonably Attributable Visibility
Impairment

    As part of the RHR, EPA revised 40 CFR 51.306(c) regarding the LTS
for RAVI to require that the RAVI plan must provide for a periodic
review and SIP revision not less frequently than every three years
until the date of submission of the state's first plan addressing
regional haze visibility impairment, which was due December 17, 2007,
in accordance with 40 CFR 51.308(b) and (c). On or before this date,
the state must revise its plan to provide for review and revision of a
coordinated LTS for addressing RAVI and regional haze, and the state
must submit the first such coordinated LTS with its first regional haze
SIP. Future coordinated LTS's, and periodic progress reports evaluating
progress towards RPGs, must be submitted consistent with the schedule
for SIP submission and periodic progress reports set forth in 40 CFR
51.308(f) and 51.308(g), respectively. The periodic review of a state's
LTS must report on both regional haze and RAVI impairment and must be
submitted to EPA as a SIP revision.

G. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(d)(4) of the RHR includes the requirement for a
monitoring strategy for measuring, characterizing, and reporting of
regional haze visibility impairment that is representative of all
mandatory Class I Federal areas within the state. The strategy must be
coordinated with the monitoring strategy required in section 51.305 for
RAVI. Compliance with this requirement may be met through
``participation'' in the IMPROVE network, i.e., review and use of
monitoring data from the network. The monitoring strategy is due with
the first

regional haze SIP, and it must be reviewed every five years. The
monitoring strategy must also provide for additional monitoring sites
if the IMPROVE network is not sufficient to determine whether RPGs will
be met.
    The SIP must also provide for the following:
     Procedures for using monitoring data and other information
in a state with mandatory Class I areas to determine the contribution
of emissions from within the state to regional haze visibility
impairment at Class I areas both within and outside the state;
     Procedures for using monitoring data and other information
in a state with no mandatory Class I areas to determine the
contribution of emissions from within the state to regional haze
visibility impairment at Class I areas in other states;
     Reporting of all visibility monitoring data to the
Administrator at least annually for each Class I area in the state, and
where possible, in electronic format;
     Developing a statewide inventory of emissions of
pollutants that are reasonably anticipated to cause or contribute to
visibility impairment in any Class I area. The inventory must include
emissions for a baseline year, emissions for the most recent year for
which data are available, and estimates of future projected emissions.
A state must also make a commitment to update the inventory
periodically; and
     Other elements, including reporting, recordkeeping, and
other measures necessary to assess and report on visibility.
    The RHR requires control strategies to cover an initial
implementation period extending to the year 2018, with a comprehensive
reassessment and revision of those strategies, as appropriate, every 10
years thereafter. Periodic SIP revisions must meet the core
requirements of section 51.308(d) with the exception of BART. The
requirement to evaluate sources for BART applies only to the first
regional haze SIP. Facilities subject-to-BART must continue to comply
with the BART provisions of section 51.308(e), as noted above. Periodic
SIP revisions will assure that the statutory requirement of reasonable
progress will continue to be met.

H. Consultation With States and Federal Land Managers (FLMs)

    The RHR requires that states consult with FLMs before adopting and
submitting their SIPs. 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 impairment
of visibility in any Class I area and to offer recommendations on the
development of the RPGs 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.

VI. EPA's Evaluation of Wyoming's Regional Haze SIP

A. Affected Class I Areas

    Pursuant to 40 CFR 51.308(d), the State identified seven mandatory
Class I areas in Wyoming: Grand Teton National Park, Yellowstone
National Park, Bridger Wilderness, Fitzpatrick Wilderness, North
Absaroka Wilderness, Teton Wilderness, and Washakie Wilderness.

B. Baseline Visibility, Natural Visibility, and Uniform Rate of
Progress

    As required by 40 CFR 51.308(d)(2), Wyoming provided baseline
visibility, natural visibility, and the URP for each Class I area in
the State. Natural background visibility, as defined in our 2003
Natural Visibility Guidance, is estimated by calculating the expected
light extinction using default estimates of natural concentrations of
fine particle components adjusted by site-specific estimates of
humidity. This calculation uses the IMPROVE equation, which is a
formula for estimating light extinction from the estimated natural
concentrations of fine particle components (or from components measured
by the IMPROVE monitors). As documented in our 2003 Natural Visibility
Guidance, EPA allows states to use ``refined'' or alternative
approaches to this guidance to estimate the values that characterize
the natural visibility conditions of Class I areas.
    One alternative approach is to develop and justify the use of
alternative estimates of natural concentrations of fine particle
components. Another alternative is to use the ``new IMPROVE equation''
that was adopted for use by the IMPROVE Steering Committee in December
2005.\8\ The purpose of this refinement to the ``old IMPROVE equation''
is to provide more accurate estimates of the various factors that
affect the calculation of light extinction.
---------------------------------------------------------------------------

    \8\ The IMPROVE program is a cooperative measurement effort
governed by a steering committee composed of representatives from
Federal agencies (including representatives from EPA and the FLMs)
and regional planning organizations. The IMPROVE monitoring program
was established in 1985 to aid the creation of Federal and State
implementation plans for the protection of visibility in Class I
areas. One of the objectives of IMPROVE is to identify chemical
species and emission sources responsible for existing anthropogenic
visibility impairment. The IMPROVE program has also been a key
participant in visibility-related research, including the
advancement of monitoring instrumentation, analysis techniques,
visibility modeling, policy formulation and source attribution field
studies.
---------------------------------------------------------------------------

    Wyoming used the new IMPROVE equation to calculate natural
conditions and baseline visibility. The natural condition for each
Class I area represents the visibility goal expressed in deciviews for
the 20% worst days and the 20% best days that would exist if there were
only naturally occurring visibility impairment. In accordance with 40
CFR 51.308(d)(2)(iii), the State calculated natural visibility
conditions based on available monitoring information and appropriate
data analysis techniques and in accordance with our 2003 Natural
Visibility Guidance. The State also calculated the number of deciviews
by which baseline conditions exceed natural conditions at each of its
Class I areas to meet the requirements of 40 CFR 51.308(d)(2)(iv)(A).
    Wyoming established the baseline visibility for the best and worst
visibility days for each Class I area based on data from the IMPROVE
monitoring sites. Each IMPROVE monitor collects particulate
concentration data which are converted into reconstructed light
extinction through a complex calculation using the IMPROVE equation
(see Chapter 13 of the SIP for more information on reconstructed light
extinction and the IMPROVE equation). Per 40 CFR 51.308(d)(2)(i), the
State calculated baseline visibility using a five-year average (2000 to
2004) of IMPROVE data for both the 20% best and 20% worst days. The
State's baseline calculations were made in accordance with our 2003
Tracking Progress Guidance.
    Pursuant to 40 CFR 51.308(d)(1)(i)(B), the State calculated the URP
for each of its Class I areas. For the 20% worst days, the URP is the
calculation of the deciview reduction needed to achieve natural
conditions by 2064. For the 20% worst days, the State calculated the
URP

in deciviews per year using the following formula: URP = [Baseline
Condition-Natural Condition]/60 years. In order to determine the
uniform progress needed by 2018 to be on the path to achieving natural
visibility conditions by 2064, the State multiplied the URP by the 14
years in the first planning period (2004-2018).
    Table 1 shows the baseline visibility, natural conditions, and URP
for each of the Class I areas. As indicated by the table, some Class I
areas share a single monitor because of the proximity of the areas to
each other.

                                   Table 1--Baseline Visibility, Natural Conditions, and URP for Wyoming Class I Areas
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             20% Worst days                                                                20% Best days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Reduction
                                                             2000-2004                       needed to     2064 Natural        Delta         2000-2004
       Wyoming class I areas            Monitor  name        Baseline        2018 URP       reach  2018     conditions      baseline--       Baseline
                                                            (deciview)      (deciview)      URP  (delta     (deciview)     2064 natural     (deciview)
                                                                                deciview)                      conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Yellowstone National Park Grand     YELL2...............            11.8            10.5             1.3            6.44            5.36            2.58
 Teton National Park Teton
 Wilderness.
North Absaroka Wilderness Washakie  NOABI...............            11.5            10.4             1.1            6.83            4.67            2.0
 Wilderness.
Bridger Wilderness Fitzpatrick      BRID1...............            11.1            10.0             1.1            6.45            4.65            2.1
 Wilderness.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We have reviewed Wyoming's baseline visibility, natural conditions,
and URP. We find they have been calculated correctly and are proposing
to approve them.

C. BART Determinations

    BART is an element of Wyoming's LTS for the first implementation
period. As discussed in more detail in section VI.D of this notice, the
BART evaluation process consists of three components: (1) An
identification of all the BART-eligible sources; (2) an assessment of
whether those BART-eligible sources are in fact subject-to-BART; and
(3) a determination of any BART controls. Wyoming addressed these steps
as follows:
1. BART Eligible Sources
    The first step of a BART evaluation is to identify all the BART-
eligible sources within the state's boundaries. Wyoming identified the
BART-eligible sources in Wyoming by utilizing the approach set out in
the BART Guidelines (70 FR 39158). This approach provides three
criteria for identifying BART-eligible sources: (1) One or more
emission units at the facility fit within one of the 26 categories
listed in the BART Guidelines; (2) the emission unit or units began
operation on or after August 6, 1962, and were in existence on August
6, 1977; and (3) combined potential emissions of any visibility-
impairing pollutant from the units that meet the criteria in (1) and
(2) are 250 tons or more per year. Wyoming reviewed source permits and
emission data from 2001-2003 to identify facilities in the BART source
categories with potential emissions of 250 tons per year or more for
any visibility-impairing pollutant from any unit or units that were in
existence on August 7, 1977 and began operation on or after August 7,
1962. The BART Guidelines direct states to address SO2,\9\
NOX, and direct PM (including both coarse particulate matter
(PM10) and PM2.5) emissions as visibility-
impairing pollutants and to exercise their ``best judgment to determine
whether VOC or NH3 emissions from a source are likely to
have an impact on visibility in an area.'' (70 FR 39162).
---------------------------------------------------------------------------

    \9\ Wyoming has elected to submit its RH SIP pursuant to the
requirements of 40 CFR 51.309. For states electing to submit under
section 309, States do not have to do a BART analysis for
SO2. SO2 controls are included in the backstop
trading program under 40 CFR 51.309(d)(4).
---------------------------------------------------------------------------

    The State analyzed the emissions from VOC and NH3 from
sources in the State and eliminated them from further consideration for
BART controls. The State evaluated the BART-eligible sources and
determined emissions of VOC and NH3 were negligible. Thus,
the State has eliminated VOC and NH3 from further
consideration for BART controls.
    We have reviewed this information and propose to accept this
determination.
    The State determined the following were BART-eligible sources:
PacifiCorp Jim Bridger, P4 Production, PacifiCorp Naughton, OCI
Wyoming, FMC Granger, Dyno Nobel, FMC Westvaco, Sinclair Casper
Refinery, Basin Electric Laramie River, Black Hills Neil Simpson 1,
PacifiCorp Wyodak, Sinclair--Sinclair Refinery, PacifiCorp Dave
Johnston, and General Chemical Green River.
    We have reviewed this information and propose to accept this
determination.
2. Sources Subject-to-BART
    The second step of the BART evaluation is to identify those BART-
eligible sources that may reasonably be anticipated to cause or
contribute to any visibility impairment at any Class I area, i.e.,
those sources that are subject-to-BART. The BART Guidelines allow
States to consider exempting some BART-eligible sources from further
BART review because they may not reasonably be anticipated to cause or
contribute to any visibility impairment in a Class I area. Consistent
with the BART Guidelines, Wyoming performed dispersion modeling on the
BART-eligible sources to assess the extent of their contribution to
visibility impairment at surrounding Class I areas.
a. Modeling Methodology
    The BART Guidelines provide that states may use the CALPUFF \10\
modeling system or another appropriate model to predict the visibility
impacts from a single source on a Class I area and to, therefore,
determine whether an individual source is anticipated to cause

or contribute to impairment of visibility in Class I areas, i.e., ``is
subject to BART.'' The Guidelines state that CALPUFF is the best
regulatory modeling application currently available for predicting a
single source's contribution to visibility impairment (70 FR 39162).
---------------------------------------------------------------------------

    \10\ Note that our reference to CALPUFF encompasses the entire
CALPUFF modeling system, which includes the CALMET, CALPUFF, and
CALPOST models and other pre and post processors. The different
versions of CALPUFF have corresponding versions of CALMET, CALPOST,
etc. which may not be compatible with previous versions (e.g., the
output from a newer version of CALMET may not be compatible with an
older version of CALPUFF). The different versions of the CALPUFF
modeling system are available from the model developer at http://www.src.com/verio/download/download.htm.
---------------------------------------------------------------------------

    The BART Guidelines also recommend that States develop a modeling
protocol for making individual source attributions, and suggest that
states may want to consult with EPA and their RPO to address any issues
prior to modeling. Wyoming used the CALPUFF model for Wyoming BART
sources in accordance with a protocol it developed titled BART Air
Modeling Protocol Individual Source Visibility Impairment Analysis,
March 2006, which was approved by EPA and is included in Chapter 6 of
the State's TSD. The Wyoming protocol follows recommendations for long-
range transport described in appendix W to 40 CFR part 51, Guideline on
Air Quality Models, and in EPA's Interagency Workgroup on Air Quality
Modeling (IWAQM) Phase 2 Summary Report and Recommendations for
Modeling Long-Range Transport Impacts as recommended by the BART
Guidelines. (40 CFR part 51, appendix Y, section III.A.3). To determine
if each BART-eligible source has a significant impact on visibility,
Wyoming used the CALPUFF model to estimate daily visibility impacts
above estimated natural conditions at each Class I area within 300 km
of any BART-eligible facility, based on maximum actual 24-hour
emissions over a three year period (2001-2003).
b. Contribution Threshold
    For States using modeling to determine the applicability of BART to
single sources, the BART Guidelines note that the first step is 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. The BART Guidelines state that, ``[a] single source
that is responsible for a 1.0 deciview change or more should be
considered to `cause' visibility impairment.'' (70 FR 39104, 39161).
The BART Guidelines also state that ``the appropriate threshold for
determining whether a source contributes to visibility impairment may
reasonably differ across States,'' but, ``[a]s a general matter, any
threshold that you use for determining whether a source ``contributes''
to visibility impairment should not be higher than 0.5 deciviews.'' Id.
Further, in setting a contribution threshold, States should ``consider
the number of emissions sources affecting the Class I areas at issue
and the magnitude of the individual sources' impacts.'' The Guidelines
affirm that States are free to use a lower threshold if they conclude
that the location of a large number of BART-eligible sources in
proximity to a Class I area justifies this approach.
    Wyoming used a contribution threshold of 0.5 deciviews for
determining which sources are subject-to-BART. By using a contribution
threshold of 0.5 deciviews, Wyoming exempted seven of the fourteen
BART-eligible sources in the State from further review under the BART
requirements. Based on the modeling results, the State determined that
P4 Production, FMC Granger,\11\ and OCI Wyoming had an impact of .07
deciview, 0.39 deciview, and 0.07 deciview, respectively, at Bridger
Wilderness. Black Hills Neil Simpson 1, Sinclair Casper Refinery, and
Sinclair--Sinclair Refinery have an impact of 0.27 deciview, 0.06
deciview, and 0.12 deciview, respectively, at Wind Cave. Dyno-Nobel had
an impact of 0.22 deciview at Rocky Mountain National Park. These
sources' modeled visibility impacts fell below the State's threshold of
0.5 deciview and were determined not to be subject-to-BART.\12\ Given
the relatively limited impact on visibility from these seven sources,
we propose to agree with Wyoming that 0.5 deciviews is a reasonable
threshold for determining whether its BART-eligible sources are
subject-to-BART.
---------------------------------------------------------------------------

    \11\ The State of Wyoming performed a refined CALPUFF visibility
modeling analysis for the two BART-eligible units at the FMC Wyoming
Granger Facility and demonstrated that the predicted 98th percentile
impacts at Bridger Wilderness Area and Fitzpatrick Wilderness Area
would be below 0.5 dv for all meteorological periods modeled. This
modeling used higher-resolution meteorological data as compared to
the data used by the State for the initial screening modeling that
identified the facility as subject-to-BART.
    \12\ CALPUFF modeling results, which provide the maximum change
in visibility are summarized in the WY BART Screening Analysis
Results and the WY BART Screening Analysis Results DV Frequency,
which can also be found in Chapter 6 of the State's TSD.
---------------------------------------------------------------------------

    Because our recommended modeling approach already incorporates
choices that tend to lower peak daily visibility impact values,\13\ our
BART Guidelines state that a State should compare the 98th percentile
(as opposed to the 90th or lower percentile) of CALPUFF modeling
results against the ``contribution'' threshold established by the State
for purposes of determining BART applicability. Wyoming used a 98th
percentile comparison that we find appropriate. Further explanation on
use of the 98th versus 90th percentile value is provided at 70 FR
39121.
---------------------------------------------------------------------------

    \13\ See our BART Guidelines, Section III.A.3.
---------------------------------------------------------------------------

c. Sources Identified by Wyoming as Subject-to-BART
    Table 2 shows the sources identified by the State as subject-to-
BART and the results of the CALPUFF modeling.

  Table 2--Wyoming Subject-to-BART Sources and CALPUFF Modeling Results
------------------------------------------------------------------------
                                                         State modeling
                                                         results--98th
         Facility name          Subject-to-BART units  percentile  delta-
                                                            deciview
------------------------------------------------------------------------
PacifiCorp--Jim Bridger.......  Units 1-4............               3.1
Basin Electric--Laramie River.  Units 1, 2 and 3.....               3.68
PacifiCorp--Dave Johnston.....  Units 3 and 4........               3.30
PacifiCorp--Naughton..........  Units 1-3............               4.36
PacifiCorp--Wyodak............  Unit 1...............               1.66
FMC--Westvaco.................  Units NS-1A and NS-1B               1.3
General Chemical--Green River.  Boilers C and D......               1.36
------------------------------------------------------------------------

    We are proposing to approve the State's determination of the
subject-to-BART sources.
3. BART Determinations and Federally Enforceable Limits
    The third step of a BART evaluation is to perform the BART
analysis. The BART Guidelines (70 FR 39164) describe the BART analysis
as consisting of the following five steps:
     Step 1: Identify All Available Retrofit Control
Technologies;
     Step 2: Eliminate Technically Infeasible Options;
     Step 3: Evaluate Control Effectiveness of Remaining
Control Technologies;
     Step 4: Evaluate Impacts and Document the Results; and
     Step 5: Evaluate Visibility Impacts.
    In determining BART, the State must consider the five statutory
factors in section 169A of the CAA: (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. See also 40 CFR 51.308(e)(1)(ii)(A). The five-
factor analysis occurs during steps 4 and 5 of the BART analysis.
    We find that Wyoming considered all five steps above in its BART
determinations, but we find that its consideration of visibility
improvement was inadequate, as explained below.
a. Visibility Improvement Modeling
    The BART Guidelines provide that states may use the CALPUFF
modeling system or another appropriate model to determine the
visibility improvement expected at a Class I area from potential BART
control technologies applied to the source. The BART Guidelines also
recommend that states develop a modeling protocol for modeling
visibility improvement, and suggest that states may want to consult
with EPA and their RPO to address any issues prior to modeling. Wyoming
developed a modeling protocol titled BART Air Modeling Protocol
Individual Source Visibility Assessments for BART Control Analyses,
September 2006, for sources to use when they performed their BART
analysis (see Chapter 6 of the State's TSD). The Wyoming protocol
follows recommendations for long-range transport described in appendix
W to 40 CFR part 51, Guideline on Air Quality Models, and in EPA's
Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary
Report and Recommendations for Modeling Long Range Transport Impacts,
as recommended by the BART Guidelines (40 CFR part 51, appendix Y,
section III.D.5).
    For the subject-to-BART PacifiCorp sources, the State's analyses
provide visibility improvement modeling results that combine the
visibility improvement from NOX, PM, and SO2
control options.\14\ From the State's modeling results, EPA could not
ascertain what the visibility improvement would be from an individual
NOX or PM control option. For Basin Electric's Laramie River
Station, the State did not provide the visibility improvement for the
SNCR control option or for PM controls. While we are able to propose
approval of the State's PM BART determinations without having
additional visibility improvement modeling for PM controls, as
discussed below, additional visibility improvement modeling to address
the NOX BART controls was needed and subsequently performed
by EPA.\15\
---------------------------------------------------------------------------

    \14\ Per the BART Guidelines, States must use CALPUFF, or other
appropriate dispersion model to determine the visibility improvement
expected at a Class I area from the potential BART control
technology applied to the source. 70 FR 39170.
    \15\ A summary of EPA's modeling methodology and results can be
found in the docket under EPA BART and RP Modeling for Wyoming
Sources.
---------------------------------------------------------------------------

b. Summary of BART Determinations and Federally Enforceable Limits
    For the subject-to-BART sources, the State provided BART analyses,
as well as additional technical information and materials, in
Attachment A to the SIP. Chapter 6 of the SIP provides a summary of the
five-factor analyses. As noted above, EPA performed the NOX
visibility improvement modeling for the control technology options
analyzed for the subject-to-BART PacifiCorp sources.\16\ EPA also
performed modeling for the visibility improvement SNCR for Basin
Electric Laramie River Units 1, 2, and 3. In addition, Wyoming did not
provide control efficiencies in their BART analysis for PM and
NOX BART controls for the PacifiCorp sources nor did the
State provide analysis for NOX BART controls for Basin
Electric Laramie River Units 1, 2, and 3. Therefore, EPA calculated the
control efficiencies shown for the PM and NOX BART controls
for the PacifiCorp sources and NOX BART controls for Basin
Electric from the emission reductions reported by Wyoming in Chapter
6.5 and Appendix A of their SIP.
---------------------------------------------------------------------------

    \16\ The cumulative visibility impact will be higher than the
98th percentile impact that is shown in the BART summary tables.
---------------------------------------------------------------------------

    EPA is proposing to approve the State's BART determinations for the
following: NOX and PM BART for FMC Westvaco Unit NS-1A and
NS-1B; NOX and PM BART for General Chemical Green River
Boiler C and Boiler D; PM BART for Basin Electric Laramie River Units
1, 2, and 3; PM BART for PacifiCorp Dave Johnston Unit 3;
NOX and PM BART for PacifiCorp Dave Johnston Unit 4; PM BART
for PacifiCorp Jim Bridger Unit 1 and Unit 2; NOX and PM
BART (including LTS controls) for PacifiCorp Jim Bridger Unit 3 and
Unit 4; NOX and PM BART for PacifiCorp Naughton Units 1, 2,
and 3; PM BART for PacifiCorp Wyodak Unit 1. A summary of the BART
determination for each source is provided below.
    EPA is proposing to disapprove the State's NOX BART
determinations, and we are proposing to issue a BART FIP, for the
following units: PacifiCorp Dave Johnston Unit 3; PacifiCorp Jim
Bridger Units 1 and 2; PacifiCorp Wyodak Unit 1; and Basin Electric
Laramie River Units 1, 2, and 3. EPA's rationale for disapproving the
State's BART determinations for these units, as well as EPA's BART FIP
determinations and emission limits can be found in section VII.A of
this notice.
i. FMC Westvaco--Units NS-1A and NS-1B
Background
    FMC's Westvaco facility is a trona mine and sodium products plant
located in Sweetwater County, Wyoming. FMC Westvaco has two existing
coal-fired boilers, Unit NS-1A and Unit NS-1B, that are subject to
BART. Unit NS-1A and Unit NS-1B each have a design heat input rate of
887 MMBtu/hr and were constructed in 1975. They are both wall-fired,
wet-bottom boilers burning subbituminous coal. The State's BART
determination can be found in Chapter 6.5.2 and Attachment A of the
SIP.
NOX BART Determination
    Units NS-1A and NS-1B are currently controlled with combustion air
control with a permit limit of 0.7 lb/MMBtu (3-hour rolling average).
The State determined that low NOX burners (LNBs) and
overfired air (OFA), LNBs and OFA with selective non-catalytic
reduction (SNCR), and LNBs and OFA with selective catalytic reduction
(SCR) were technically feasible for reducing NOX emissions
at Unit NS-1A and NS-1B. The State did not identify any technically
infeasible options. The State did not identify any energy or non-air
quality environmental impacts that would preclude the selection of any
of the controls evaluated, and there are no remaining-useful-life
issues for this

source. A summary of the State's NOX BART analysis and the
visibility impacts is provided in Table 3. Baseline NOX
emissions are 2,719.5 tpy for each unit based on a heat input rate of
887 MMBtu/hr and 8,760 hours of operation per year.

                                      Table 3--Summary of FMC Westvaco Unit NS-1A and Unit NS-1B NOX BART Analysis*
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                                (Delta dv for
                                                                  Emission rate                                         Average cost       the maximum
             Control  technology                   Control      (lb/MMBtu)  (30-      Emission         Annualized       effectiveness    98th percentile
                                               efficiency  (%)     day rolling    reduction  (tpy)        costs            ($/ton)          impact at
                                                                    average)                                                                 Bridger
                                                                                Wilderness
                                                                                Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNB + SOFA..................................                50              0.35           1,359.7          $413,145              $304              0.13
LNB + SOFA + SNCR...........................                70              0.21           1,903.6         1,281,851               673              0.19
LNB + SOFA + SCR............................                85              0.10           2,331.0         1,281,851             3,493              0.24
--------------------------------------------------------------------------------------------------------------------------------------------------------
* This table reflects the costs and visibility improvements per boiler.

    Incremental cost effectiveness for the controls evaluated is as
follows: LNB plus SOFA and SNCR: $1,597/ton, and LNB plus SOFA and SCR:
$16,051/ton.\17\
---------------------------------------------------------------------------

    \17\ Incremental cost effectiveness for each option is the
difference in total annual costs between that option and the next
most stringent option, divided by the difference in emissions, after
controls have been applied, between those two control options.
---------------------------------------------------------------------------

    Based on its consideration of the five factors, the State
determined that LNBs plus OFA are reasonable for BART. The State
determined that the other control options were not reasonable based on
the cost effectiveness and associated visibility improvement. The State
has determined that NOX BART emission limits for FMC
Westvaco Unit NS-1A and Unit MS-1B are 0.35 lb/MMBtu (30-day rolling
average), 284 lb/hr (30-day rolling average), and 1,244 tpy.
    We agree with the State's conclusions, and we are proposing to
approve its NOX BART determinations for FMC Westvaco Unit
NS-1A and Unit NS-1B.
PM BART Determination
    Unit NS-1A and Unit NS-1B are currently controlled for PM emissions
by electrostatic precipitators (ESPs). The units currently have a PM
emission limit of 0.05 lb/MMBtu. The State determined that fabric
filters on the wet scrubber, addition of an ESP downstream of the wet
scrubber, and replacement of the ESPs with fabric filters were
technically feasible control options. The State did not identify any
energy or non-air quality environmental impacts that would preclude the
selection of any of the controls evaluated, and there are no remaining-
useful-life issues for this source. A summary of the State's PM BART
analysis is provided in Table 4 below. Baseline PM emissions are 197
tpy for each unit based on a heat input rate of 887 MMBtu/hr and 8,760
hours of operation per year.

                                      Table 4--Summary of FMC Westvaco Unit NS-1A and Unit NS-1B PM BART Analysis *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Emission rate
                                                                    Control       (lb/MMBtu)  (30-      Emission         Annualized       Average cost
                      Control technology                        efficiency  (%)     day rolling     reduction  (tpy)        costs         effectiveness
                                                                                average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter on Wet Scrubber................................              21.4              0.04               41.7        $1,791,364           $42,948
ESP after Wet Scrubber.......................................              63.3              0.019             123.3         3,507,617            28,448
Replace ESP with Fabric Filter...............................              71.3              0.015             138.8         4,116,036            29,654
--------------------------------------------------------------------------------------------------------------------------------------------------------
* This table reflects the costs and visibility improvements per boiler.

    Given the high cost of controls, which are higher than what EPA, or
other states have considered reasonable for PM, FMC did not evaluate
the visibility improvement that would result from the PM controls
evaluated. Previous visibility modeling analyses from the source
indicate that the contribution in visibility degradation from PM is
minor when compared to the contributing effects of NOX and
SO2. Results from FMC's visibility modeling screening and
analysis confirm this conclusion and are discussed in further detail
within the comprehensive visibility analysis included as part of FMC's
BART application (see Attachment A to the SIP). The State agreed with
FMC's conclusions and did not require FMC to perform additional
visibility analyses for the PM control options.
    The State determined that the current ESP control was reasonable
for PM BART. The State rejected other controls as being reasonable for
BART because of the high cost effectiveness. The State has determined
that the PM BART emission limits for FMC Westvaco Unit NS-1A and NS-1B
are 0.05 lb/MMBtu, 45.0 lb/hr, and 197 tpy.
    We agree with the State's conclusions, and we are proposing to
approve its PM BART determinations for FMC Westvaco Unit NS-1A and Unit
NS-1B.
ii. General Chemical Green River--Boilers C and D
    General Chemical Green River is a trona mine and sodium products
plant. General Chemical's two existing coal-fired boilers, C and D, are
co-located at the facility power plant. Both boilers burn low sulfur
bituminous coal, and they supply power and process steam to mining and
ore processing operations. Both boilers are tangentially fired using
in-line coal pulverizers. The firing rate for Boiler C is 534 MMBtu/hr
and 880 MMBtu/hr for Boiler D. The State's BART determination can be
found in Chapter 6.5.3 and Attachment A of the SIP.

NOX BART Determination
    Boiler C and Boiler D are currently controlled with LNBs plus OFA
with a permit limit of 0.7 lb/MMBtu (3-hour rolling average). On August
7, 2009, the State issued a BART permit to General Chemical that
required the source to meet a NOX emission limit of 0.32 lb/
MMBtu (30-day rolling average) for Boiler C and Boiler D. The State
assumed the source could meet this emission limit with the installation
and operation of new LNBs with the existing OFA. Upon further
investigation, the source determined it could not meet a limit of 0.32
lbs/MMBtu with new LNBs and the existing OFA.
    In response to the additional information from the source, the
State reexamined its BART determination for Boiler C and D. The State
determined that installing SOFA in addition to the existing LNBs and
OFA could achieve an emission limit of 0.28 lb/MMBtu. Since SOFA in
conjunction with the existing NOX controls could achieve
better emission reductions than new LNBs plus OFA, the State eliminated
the latter from further consideration in the BART analysis. The State
determined SNCR and SCR were also technically feasible. The State did
not identify any technically infeasible options.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there are no remaining-useful-life issues for
this source. A summary of the State's NOX BART analysis and
visibility impacts is provided in Tables 5 and 6 below. Baseline
NOX emissions are 1,167 tpy for Boiler C and 1,816 tpy for
Boiler D based on an average of 2001-2003 actual emissions.

                                      Table 5--Summary of General Chemical--Green River Boiler C NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                  Emission rate                                                           (Delta dv for
                                                   Control      (lb/MMBtu)  (30-      Emission         Annualized       Average cost       the maximum
             Control  technology               efficiency  (%)     day rolling    reduction  (tpy)        costs         effectiveness    98th percentile
                                                                    average)                                               ($/ton)          impact at
                                                                                Bridger
                                                                                Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing LNBs with SOFA.....................                44              0.28               512          $757,711            $1,480              0.05
SNCR........................................                50              0.35               584         1,433,720             2,455              0.08
SCR.........................................                80              0.14               934         2,434,809             2,607              0.14
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the control technologies
evaluated is as follows: SNCR: $4,782/ton, and SCR: $3,156/ton.

                                      Table 6--Summary of General Chemical--Green River Boiler D NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                  Emission rate                                                           (Delta dv for
                                                   Control      (lb/MMBtu)  (30-      Emission         Annualized       Average cost       the maximum
             Control  technology               efficiency  (%)     day rolling    reduction  (tpy)        costs         effectiveness    98th percentile
                                                                    average)                                               ($/ton)          impact at
                                                                                Bridger
                                                                                Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing LNBs with SOFA.....................                41              0.28               737          $943,549            $1,280              0.07
SNCR........................................                50              0.35               908         1,486,581             3,176              0.12
SCR.........................................                80              0.14             1,453         3,399,266             3,510              0.17
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the control technologies
evaluated is as follows: SNCR: $2,913/ton, and SCR: $4,342/ton.
    Based on its consideration of the five factors, the State
determined that NOX BART is the existing LNBs with new SOFA,
or a comparable performing technology. The State determined that SNCR
and SCR were not reasonable based on the high cost effectiveness and
low visibility improvement. The State determined the NOX
BART emission limits for General Chemical Green River Boiler C are 0.28
lb/MMBtu (30-day rolling average), 149.5 lb/hr (30-day rolling average)
and 654.9 tpy, and that the NOX BART emission limits for
Boiler D are 0.28 lb/MMBtu (30-day rolling average), 246.4 lb/hr (30-
day rolling average) and 1,079.2 tpy.
    We agree with the State's conclusions, and we are proposing to
approve its NOX BART determinations for General Chemical
Green River--Boiler C and D.
PM BART Determination
    Boiler C and D are currently controlled by ESPs with a permit limit
of 50 lb/hr and 80 lb/hr, respectively. General Chemical addressed PM
emissions through an abbreviated analysis by using PM BART information
from FMC Westvaco, as discussed above. The facilities are similar in
size and located about ten miles apart. Baseline PM emissions for
Boiler C are 98 tpy and 161 tpy for Boiler D based on the average of
2001-2003 actual emissions. As discussed above, visibility modeling
screening and analyses for FMC Westvaco indicate that the contribution
in visibility degradation from PM for a source comparable to Boiler C
and Boiler D is minor. Additionally, costs for controlling PM from
similar boilers are high as indicated by FMC analysis for Westvaco.
    The State accepted General Chemical's abbreviated PM BART analysis.
The State determined that the current ESP control was reasonable for PM
BART. The State rejected other controls as being reasonable for BART
because of the high cost effectiveness. The State determined that the
PM BART emission limits for Boiler C are 0.09 lb/MMBtu, 50 lb/hr, and
219 tpy, and that the PM BART emissions limits for Boiler D are 0.09
lb/MMBtu, 80 lb/hr, and 350.4 tpy.

    We agree with the State's conclusions, and we are proposing to
approve its PM BART determination for General Chemical Green River
Boiler C and D.
iii. Basin Electric Laramie River Station--Units 1-3
    Basin Electric Laramie River Station is located in Platte County,
Wyoming. Laramie River Station is comprised of three 550-MW dry-bottom,
wall-fired boilers (Units 1, 2, and 3) burning subbituminous coal for a
total net generating capacity of 1,650 MW. All three units are subject-
to-BART. The State's BART determination can be found in Chapter 6.5.8
and Attachment A of the SIP (The NOx BART analysis is discussed in
section VII.A of this notice).
PM BART Determination
    Laramie River Units 1, 2, and 3 are currently controlled with ESPs
with a permit limit of 0.03 lb/MMBtu. The State determined that fabric
filters were technically feasible for Unit 3 but not Units 1 and 2.
Units 1 and 2 are controlled with wet flue gas desulfurization and
fabric filters cannot be used downstream of such a system. The State
determined that flue gas treatment and GE Max-9 hybrid were technically
infeasible for all three units. Thus, the only technically feasible
control option for PM is fabric filters on Unit 3.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there are no remaining-useful-life issues for
this source. A summary of the State's PM BART analysis for Unit 3 is
provided in Table 7 below. Baseline PM emissions are 716 tpy for the
unit based on 2001-2003 actual emissions.

                                        Table 7--Summary of Basin Electric Laramie River Unit 3 PM BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Emission rate
                                                                     Control      (lb/MMBtu)  (30-      Emission                          Average cost
                      Control technology                         efficiency (%)      day rolling    reduction  (tpy)  Annualized costs    effectiveness
                                                                                average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter--Peak Rate for Lost Generating Costs............                50             0.015               358      $194,809,000           $54,707
Fabric Filter Non-Peak Rate for Lost Generating Costs.........                50             0.015               358       134,934,000            40,156
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State did not provide visibility improvement modeling for
fabric filters, but EPA is proposing to conclude this is reasonable
based on the high cost effectiveness of fabric filters at each of the
units, which is higher than EPA or other state have considered
reasonable for PM BART.
    Based on its consideration of the five factors, the State
determined that the current ESPs are reasonable for PM BART, as fabric
filters on Unit 3 are not cost-effective and there are no other
technically feasible controls for Units 1 and 2. The State determined
the PM BART emission limits for Laramie River Unit 1 and Unit 2 are
0.03 lb/MMBtu, 193 lb/hr, and 844 tpy, and the PM BART emission limits
for Laramie River Unit 3 are 0.03 lb/MMBtu, 198 lb/hr, and 867 tpy.
    We agree with the State's conclusions, and we are proposing to
approve its PM BART determination for Basin Electric Laramie River
Units 1, 2, and 3.
iv. PacifiCorp Dave Johnston--Units 3 and 4
Background
    PacifiCorp Dave Johnston power plant is located in Converse County,
Wyoming. Dave Johnston Power Plant is comprised of four units burning
pulverized subbituminous Powder River Basin coal. Units 3 and 4 are the
only units subject-to-BART. Dave Johnston Unit 3 is a nominal 230-MW
pulverized coal-fired boiler that commenced service in 1964. It is
equipped with burners in a cell configuration. Dave Johnston Unit 4 is
a nominal 330-MW pulverized coal-fired boiler that commenced service in
1972. It is a tangential-fired boiler. The State's BART analysis can be
found in Chapter 6.5.5 and Appendix A of the SIP (The NOX
BART determination for Dave Johnston Unit 3 is discussed in section
VII.A of this notice).
NOX BART Determination for Unit 4
    Unit 4 is currently controlled with LNBs that were placed in
operation in 1976. The State determined LNBs with advanced OFA, LNBs
with advanced OFA and SNCR, and LNBs with advanced OFA and SCR were
technically feasible for controlling NOX emissions for Unit
4. The State did not identify any technically infeasible controls.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there are no remaining-useful-life issues for
this source. Baseline NOX emissions are 8,566 tpy for Unit 4
based on unit heat input rate of 2,500 MMBtu/hr and 7,884 hours of
operation. A summary of the State's NOX BART analysis and
the visibility impacts is provided in Table 8 below.

                                               Table 8--Summary of Dave Johnston Unit 4 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                  Emission rate                                                          (delta deciview
                                                   Control      (lb/MMBtu)  (30-      Emission                          Average cost     for the maximum
             Control technology                efficiency (%)      day rolling    reduction  (tpy)  Annualized costs    effectiveness    98th percentile
                                                                    average)                                               ($/ton)       impact at Wind
                                                                                Cave  National
                                                                                Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNB with advanced OFA.......................              71.7              0.15             6,142          $841,527              $137              0.71
New LNB with advanced OFA and SNCR..........              77.4              0.12             6,626        $2,141,786              $323              0.80
LNB with advanced OFA and SCR...............              86.8              0.07             7,435       $16,430,528            $2,210              0.97
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental costs for the controls evaluated are as follows: New
LNB with advanced OFA and SNCR: $2,686/ton; and LNB with advanced OFA
and SCR: $17,662/ton.
    Based on its consideration of the five factors, the State
determined LNBs with advanced OFA was reasonable for NOX
BART for Dave Johnston Unit 4. The State determined the NOX
BART emission limits for Unit 4 are 0.15 lb/MMBtu (30-day rolling
average), 615 lb/hr (30-day rolling average), and 2,694 tpy.
    We find it is reasonable for the State to eliminate higher
performing control options (i.e., LNBs with advanced OFA plus SNCR and
LNBs with advanced OFA plus SCR). The incremental cost effectiveness of
achieving 0.07 lb/MMBTU with SCR over achieving 0.15 lb/MMBTU with LNBs
is $17,662, with a 0.26 delta deciview visibility improvement. The
incremental cost effectiveness of SNCR over LNBs is $2,686 with an
incremental visibility improvement of 0.09.
    Based on our examination of the State's costs estimates, emission
reductions, and the predicted visibility improvement, we agree with the
State's conclusions, and we are proposing to approve its NOX
BART determination for PacifiCorp Dave Johnston Unit 4.
PM BART Determination
    Units 3 and 4 are currently controlled with fabric filters
installed in 2008 with an emission limit of 0.015 lb/MMBtu. The State
determined that fabric filters represent the most stringent PM control
technology and that 0.015 lb/MMBtu represents the most stringent
emission limit. Consistent with the BART Guidelines, the State did not
provide a five-factor analysis because the State determined BART to be
the most stringent control technology and limit (70 FR 39165). The
State determined that the PM BART emission limits for Unit 3 are 0.015
lb/MMBtu, 42.1 lb/hr, and 184 tpy and the PM BART emission limits for
Unit 4 are 0.015 lb/MMBtu (30-day rolling average), 61.5 lb/hr, and 269
tpy.
    We agree with the State's conclusions, and we are proposing to
approve its PM BART determination for Dave Johnston Units 3 and 4.
v. PacifiCorp Jim Bridger--Units 1-4
Background
    PacifiCorp's Jim Bridger Power Plant is located in Sweetwater
County, Wyoming. Jim Bridger is comprised of four identically sized
nominal 530 MW tangentially fired boilers burning pulverized coal for a
total net generating capacity of 2,120 MW. Jim Bridger Unit 1 was
placed in service in 1974, Unit 2 in 1975, Unit 3 in 1976, and Unit 4
in 1979. The State's BART determination can be found in Chapter 6.5.4
and Appendix A of the SIP (The NOX BART determination for
Jim Bridger Units 1 and 2 is discussed in section VII.A of this
notice).
NOX BART Determination for Jim Bridger Units 3 and 4
    PacifiCorp Jim Bridger Units 3 and 4 are equipped with early
generation LNBs with a permit limit of 0.70 lb/MMBtu (3-hour fixed).
The State determined that LNBs with SOFA, LNBs with SOFA plus SNCR, and
LNBs with SOFA plus SCR were technically feasible for controlling
NOX emissions. The State did not identify any technically
infeasible options.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there are no remaining-useful-life issues for
this source. Baseline NOX emissions are 10,643 tons for both
units based on unit heat input rate of 6,000 MMBtu/hr and 7,884 hours
of operation. A summary of the State's NOX BART analysis and
the visibility impacts is provided in Table 9 below.
---------------------------------------------------------------------------

    \18\ Unit 4 has different modeling results as the stack
parameters used in the modeling are different enough from Units 1-3
to yield different modeled results.

                                    Table 9--Summary of Jim Bridger Units 3 and 4 NOX BART Analysis--Costs per Boiler
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                                (delta deciview
                                                                  Emission rate                                         Average cost     for the maximum
             Control technology                    Control      (lb/MMBtu)  (30-      Emission      Annualized costs    effectiveness    98th percentile
                                               efficiency (%)      day rolling     reduction (tpy)                         ($/ton)        impact at Mt.
                                                                    average)                                                                 Zirkel
                                                                                Wilderness)-
                                                                                units 3/4 \18\
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNB with SOFA...............................              42.2              0.26             4,493        $1,144,969              $255         0.41/0.47
New LNB with SOFA and SNCR..................              55.6              0.20             5,913         2,710.801               459         0.53/0.62
LNB with SOFA and SCR.......................              84.4              0.07             8,987        20,296,400             2,258         0.80/0.82
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the control evaluated is as
follows: New LNB with SOFA and SNCR: $1,103/ton, and LNB with SOFA and
SCR: $5,721/ton.
    The State determined the cost of compliance was high for SCR. The
State determined that LNBs with SOFA were reasonable for NOX
BART for Jim Bridger Units 3 and 4. The State determined the
NOX BART emission limits for Jim Bridger Units 3 and 4 are
0.26 lb/MMBtu (30-day rolling average), 1,560 lb/hr (30-day average),
and 6,833 tpy.
    The State is requiring PacifiCorp to install additional controls
under its LTS. The State determined that based on the cost of
compliance and visibility improvement presented by PacifiCorp in the
BART applications for Jim Bridger Units 3 and 4 and taking into
consideration the logistical challenge of managing multiple pollution
control installations within the regulatory time allotted for
installation of BART by the RHR, additional controls would be required
under the LTS but not BART (see Chapter 8.3.3 of the SIP). With respect
to Jim Bridger Units 3 and 4, the State has required PacifiCorp to
install SCR, or other NOX control systems, to achieve an
emission limit or otherwise reduce NOX emissions to achieve
a 0.07 lb/MMBtu 30-day rolling average NOX emissions rate.
PacifiCorp is required to meet the 0.07 lb/MMBtu emission rate on Unit
3 prior to December 31, 2015 and on Unit 4 prior to December 31, 2016.
    EPA does not agree with the State's conclusion that a limit of 0.26
lb/MMBtu is reasonable for BART for Jim Bridger Units 3 and 4, which
can be achieved with the installation and

operation on LNBs with SOFA. In particular, the cost effectiveness
values for LNBs with SOFA plus SCR at each unit is $2,258 with
approximately 0.80 delta deciview visibility improvement. The cost
effectiveness values are reasonable and the visibility improvement
significant for LNBs with SOFA plus SCR. In addition, the costs are
within the range that Wyoming, other states, and we have considered
reasonable in the BART context.\19\ LNBs with SOFA plus SCR would
result in an additional reduction of 4,474 tpy of NOX
emissions at each unit. This difference is substantial. We find that it
was unreasonable for the State not to determine that LNBs with SOFA
plus SCR was NOX BART for Jim Bridger Units 3 and 4.
---------------------------------------------------------------------------

    \19\ Wyoming determined that LNBs with OFA and SCR was BART for
Naughton Unit 3. The cost effectiveness of SCR for Naughton Unit 3
is $2,830 with 1 deciview of visibility improvement.
---------------------------------------------------------------------------

    Based on our examination of the State's costs estimates, emission
reductions, and the predicted visibility improvement, we propose to
find it reasonable that NOx BART for Jim Bridger Units 3 and 4 is LNBs
with SOFA plus SCR at an emission limit of 0.07 lb/MMBtu. Though we do
not agree with the State's BART determination, the State is requiring
PacifiCorp to install controls as part of the LTS that are equivalent
to what EPA's is proposing to determine is reasonable for BART. The
State is requiring PacifiCorp to install the LTS controls within the
timeline that BART controls would have to be installed pursuant to 40
CFR 51.308(e)(iv). Thus, we are proposing to approve the State's
compliance schedule and emission limit of 0.07 lb/MMBtu for Jim Bridger
Units 3 and 4 as meeting the BART requirements.
PM BART Determination for Jim Bridger Units 1-4
    Units 1, 2, 3, and 4 are currently controlled for PM with ESPs and
flue gas conditioning (FGC). The current permit limit for all four
units is 0.03 lb/MMBtu. The State determined that fabric filters were
technically feasible for controlling PM emissions. The State did not
identify any technically infeasible controls. The State did not
identify any energy or non-air quality environmental impacts that would
preclude the selection of any of the controls evaluated, and there are
no remaining-useful-life issues for this source. A summary of the
State's PM BART analyses for Units 1-4 is provided in Table 10 below.
Baseline PM emissions are 1,064 tpy for Unit 1, 1,750 tpy for Unit 2,
1,348 tpy for Unit 3, and 710 tpy for Unit 4 based on unit heat input
rate of 6,000 MMBtu/hr and 7,884 hours of operation per year.

                                        Table 10--Summary of PacifiCorp Jim Bridger Units 1-4 p.m. BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Emission rate
                                                                     Control      (lb/MMBtu)  (30-      Emission                          Average cost
                      Control technology                         efficiency (%)      day rolling    reduction  (tpy)  Annualized costs    effectiveness
                                                                                average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter--Unit 1.........................................              66.6             0.015               709        $6,367,118            $8,980
Fabric Filter--Unit 2.........................................              79.7             0.015             1,395         6,357,658             4,557
Fabric Filter--Unit 3.........................................              73.7             0.015               993         6,337,434             6,382
Fabric Filter--Unit 4.........................................                50             0.015               355         6,367,118            17,936
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State did not provide visibility improvement modeling for
fabric filters, but EPA is proposing to conclude this is reasonable
based on the high cost effectiveness of fabric filters at each of the
units. In addition, we anticipate that the visibility improvement that
would result from lowering the limit from 0.03 lb/MMBtu to 0.015 lb/
MMBtu would be insignificant based on the State's analysis.\20\
---------------------------------------------------------------------------

    \20\ The cumulative 3-year averaged visibility improvement from
new LNB with separated OFA, upgraded wet FGD, and FGC for enhanced
ESP with FGC (Post-Control Scenario 1) across the three Class I
areas achieved with LNB and separated OFA, upgraded wet FGD, and
adding a polishing fabric filter (Post-Control Scenario 2) was 0.095
delta dv from Unit 1, 0.090 delta dv from Unit 2, 0.089 delta dv
from Unit 3 and 0.025 delta dv from Unit 4.
---------------------------------------------------------------------------

    Based on its consideration of the five-factors, the State
determined the current ESPs with FGC were reasonable for BART. The
State determined that fabric filters were not reasonable based on the
high cost effectiveness. The State determined that the PM BART emission
limits for Jim Bridger Units 1 through 4 are 0.03 lb/MMBtu, 180 lb/hr,
and 788 tpy.
    We agree with the State's conclusions, and we are proposing approve
its PM BART determination for Jim Bridger Units 1-4.
vi. PacifiCorp Naughton Units 1-3
    PacifiCorp Naughton is located in Lincoln County, Wyoming. Naughton
is comprised of three pulverized coal-fired units with a total net
generating capacity of 700 MW. Naughton Unit 1 generates a nominal 160
MW and commenced operation in 1963. Naughton Unit 2 generates a nominal
210 MW and commenced operation in 1968. Naughton Unit 3 generates a
nominal 330 MW and commenced operation in 1971. All three boilers are
tangentially fired boilers. The State's BART determination can be found
in Chapter 6.5.6 and Appendix A of the SIP.
NOX BART Determination
    Naughton Unit 1 and Unit 2 are currently controlled for
NOX emissions with good combustion practices with
NOX emission limits of 0.75 lb/MMBtu (3-hour block) and 0.58
lb/MMBtu (annual). Naughton Unit 3 is currently controlled with LNBs
with OFA with permit limits of 0.75 lb/MMBtu (93-hour block) and 0.58
lb/MMBtu (annual). The State determined that LNBs with OFA, LNBs with
OFA and SNCR, and LNBs with OFA and SCR were all technically feasible
for controlling NOX emissions from Unit 1 and Unit 2. The
State determined that tuning the existing LNBs, existing LNBs with OFA
and SNCR, and existing LNBs with OFA and SCR were all technically
feasible for controlling NOX emissions from Unit 3. The
State did not identify any technically infeasible options.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there no remaining-useful-life issues for this
source. A summary of the State's NOX BART analyses for Units
1-3 is provided in Tables 11, 12, and 13 below. Baseline NOx emissions
are 4,230 tpy for Unit 1, 5,109 tpy for Unit 2, and 6,563 tpy for Unit
3 based on the unit heat input rate

of 3,700 MMBtu/hr and 7,884 hours of operation per year.

                                                 Table 11--Summary of Naughton Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                                (Delta deciview)
                                                                  Emission rate                                         Average cost     (Delta deciview
             Control technology                    Control      (lb/MMBtu)  (30-      Emission      Annualized costs    effectiveness    for the maximum
                                               efficiency (%)      day rolling    reduction  (tpy)                         ($/ton)       98th percentile
                                                                    average)                                                                Impact at
                                                                                Bridger
                                                                                Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...............................              55.2              0.26             2,334          $993,248              $426              0.79
LNBs with OFA and SNCR......................              63.8              0.21             2,699         1,972,363               731              0.80
LNBs with OFA and SCR.......................              87.9              0.07             3,720        10,231,210             2,750              1.07
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the controls evaluated are as
follows: LNBs with OFA and SNCR: $2,683/ton, and LNBs with OFA and SCR:
$8,089/ton.

                                                 Table 12--Summary of Naughton Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                                (Delta deciview)
                                                                  Emission rate                                             Cost         (Delta deciview
             Control technology                    Control      (lb/MMBtu)  (30-      Emission      Annualized costs    effectiveness    for the maximum
                                               efficiency (%)      day rolling    reduction  (tpy)                         ($/ton)       98th percentile
                                                                    average)                                                                Impact at
                                                                                Bridger
                                                                                Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...............................              51.9              0.26             2,649          $945,683              $357              0.70
LNBs with OFA and SNCR......................              61.1              0.21             3,122         2,260,957               724              0.74
LNBs with OFA and SCR.......................                87              0.07             4,447        12,664,919             2,848              1.10
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the controls evaluated are as
follows: LNBs with OFA and SNCR: $2,781/ton, and LNBs with OFA and SCR:
$7,852/ton.

                                                 Table 13--Summary of Naughton Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Visibility
                                                                                improvement
                                                                  Emission rate                                                           (Delta dv for
                                                   Control      (lb/MMBtu)  (30-      Emission                          Average cost    the maximum 98th
             Control technology                efficiency (%)      day rolling    reduction  (tpy)  Annualized costs  effectiveness ($/    percentile
                                                                    average)                                                ton)            impact at
                                                                                Bridger
                                                                                Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tuning Existing LNBs........................              17.8              0.37             1,167           $95,130               $82              0.25
Existing LNBs with OFA and SNCR.............              33.3              0.30             2,188         1,916,039               876              0.46
Existing LNB with OFA and SCR...............              84.4              0.07             5,542        15,682,702             2,830              1.00
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Incremental cost effectiveness for the controls evaluated are as
follows: LNBs with OFA and SNCR: $1,783; and LNBs with OFA and SCR:
$4,105.
    Based on its consideration of the five factors, the State
determined LNBs with OFA was reasonable for NOX BART for
Unit 1 and Unit 2. The State determined SNCR and SCR were not
reasonable based on the high cost effectiveness and associated
visibility improvement. The State determined the NOX BART
emission limits for Naughton Unit 1 are 0.26 lb/MMBtu (30-day rolling
average), 481 lb/hr (30-day rolling average), and 2,107 tpy, and the
NOX BART emission limits for Naughton Unit 2 are 0.26 lb/
MMBtu (30-day rolling average), 624 lb/hr (30-day rolling average), and
2,733 tpy. Based on its consideration of the five factors, the State
determined that the existing LNBs with OFA plus SCR was NOX
BART for Unit 3. The State determined the NOX BART emission
limits for Naughton Unit 3 are 0.07 lb/MMBtu (30-day rolling average),
259 lb/hr (30-day rolling average), and 1,134 tpy.
    We find it is reasonable for the State to eliminate higher
performing control options for Units 1 and 2 (i.e., LNBs with advanced
OFA plus SNCR and LNBs with advanced OFA plus SCR. The incremental cost
effectiveness of LNBs with OFA plus SCR over LNBs with OFA is
approximately $8,000 for each unit. The incremental cost effectiveness
of LNBs with OFA plus SNCR over LNBs with OFA is approximately $2,700
for each unit, with incremental visibility improvement of 0.01 delta
deciviews at

Unit 1 and 0.04 delta deciviews at Unit 2.
    Based on our examination of the State's costs estimates, emission
reductions, and the predicted visibility improvement, we agree with the
State's conclusions, and we are proposing to approve the State's
NOX BART determinations for PacifiCorp Naughton Units 1, 2,
and 3.
PM BART Determination
    Units 1 and 2 are currently controlled for PM with ESPs and FGC.
The current permit limit for Units 1 and 2 is 0.04 lb/MMBtu. Unit 3 is
required by permit to install fabric filters for both Units by 2014
with a permit limit of 0.15 lb/MMBtu. The State determined that fabric
filters were technically feasible for controlling PM emissions for
Units 1 and 2. The State did not identify any technically infeasible
controls. The State determined that a fabric filter on Unit 3
represents the most stringent PM control technology and that 0.015 lb/
MMBtu represents the most stringent emission limit. Consistent with the
BART Guidelines, the State did not provide a full five-factor analysis
because the State determined BART to be the most stringent control
technology and limit.
    The State did not identify any energy or non-air quality
environmental impacts that would preclude the selection of any of the
controls evaluated, and there are no remaining-useful-life issues for
this source. A summary of the State's PM BART analyses for Units 1 and
2 is provided in Table 14 below. Baseline emissions for Unit 1 are 409
tpy and 605 tpy for Unit 2 based on unit heat input rate of 1,850
MMBtu/hr and 7,884 hours of operation per year.

                                       Table 14--Summary of PacifiCorp Naughton Unit 1 and Unit 2 PM BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Emission Rate
                                                                     Control      (lb/MMBtu)  (30-      Emission                          Average Cost
                      Control technology                         Efficiency (%)      day rolling    Reduction  (tpy)  Annualized Costs  Effectiveness ($/
                                                                                Average)                                                ton)