[Federal Register Volume 78, Number 162 (Wednesday, August 21, 2013)]
[Proposed Rules]
[Pages 51686-51695]
[FR Doc No: 2013-20317]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2013-0227, FRL-9900-27-Region 6]

Approval and Promulgation of Implementation Plans; Oklahoma;
Regional Haze and Interstate Transport Affecting Visibility State
Implementation Plan Revisions; Withdrawal of Federal Implementation
Plan for American Electric Power/Public Service Company of Oklahoma

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to approve a revision to the Oklahoma
Regional Haze State Implementation Plan (SIP) submitted on June 20,
2013 by the Oklahoma Secretary of Environment addressing the Best
Available Retrofit Technology (BART) requirements for sulfur dioxide
(SO2) and oxides of nitrogen (NOX) for Units 3
and 4 of the American Electric Power/Public Service Company (AEP/PSO)
Northeastern Power Station in Rogers County, Oklahoma. The EPA is
proposing to find that this revised BART determination meets the
requirements of the Clean Air Act (CAA) and the Regional Haze Rule. We
are also proposing to approve a related SIP revision submitted to
address the impact of emissions of Northeastern Units 3 and 4 as
required by CAA provisions concerning non-interference with programs to
protect visibility in other states. In conjunction with these proposed
approvals, we propose to

withdraw federal implementation plan (FIP) emission limits for
SO2 that would otherwise apply to Northeastern Units 3 and
4. The EPA is taking this action under section 110 of the CAA.

DATES: Written comments must be received on or before September 20,
2013.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R06-
OAR-2013-0227 by one of the following methods:
     www.regulations.gov. Follow the online instructions for
submitting comments.
     Email: Mr. Guy Donaldson at<EMAIL_ADDRESS>Please
also send a copy by email to the person listed in the FOR FURTHER
INFORMATION CONTACT section below.
     Mail or delivery: Mr. Guy Donaldson, Chief, Air Planning
Section (6PD-L), Environmental Protection Agency, 1445 Ross Avenue,
Suite 1200, Dallas, Texas 75202-2733. Deliveries are accepted only
between the hours of 8 a.m. and 4 p.m. weekdays, and not on legal
holidays. Special arrangements should be made for deliveries of boxed
information.
    Instructions: Direct your comments to Docket ID No. EPA-R06-OAR-
2013-0227. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through www.regulations.gov
or email. The www.regulations.gov Web site is an ``anonymous access''
system, which means the 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
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, the 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 the 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.
    Docket: All documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available (e.g., CBI or other information
whose disclosure is restricted by statute). Certain other material,
such as copyrighted material, will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically at www.regulations.gov or in hard copy at the Air
Planning Section (6PD-L), Environmental Protection Agency, 1445 Ross
Avenue, Suite 700, Dallas, Texas 75202-2733. The file will be made
available by appointment for public inspection in the Region 6 FOIA
Review Room between the hours of 8:30 a.m. and 4:30 p.m. weekdays
except for legal holidays. Contact the person listed in the FOR FURTHER
INFORMATION CONTACT paragraph below or Mr. Bill Deese at<PHONE_NUMBER>
to make an appointment. If possible, please make the appointment at
least two working days in advance of your visit. There will be a fee of
15 cents per page for making photocopies of documents. On the day of
the visit, please check in at the EPA Region 6 reception area at 1445
Ross Avenue, Suite 700, Dallas, Texas.
    The State submittal is also available for public inspection during
official business hours, by appointment, at the Oklahoma Department of
Environmental Quality (ODEQ), Air Quality Division, 707 North Robinson,
P.O. Box 1677, Oklahoma City, Oklahoma 73101-1677.

FOR FURTHER INFORMATION CONTACT: Terry Johnson at telephone number
(214) 665-2154, email<EMAIL_ADDRESS>or the above address for
EPA's Region 6 office.

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

Table of Contents

I. Background on the Oklahoma Regional Haze SIP and FIP
II. Background for EPA's Proposed Action
    A. Definition of Regional Haze
    B. Regional Haze Rules and Regulations
    C. 1997 NAAQS for Ozone and PM2.5 and CAA Section
110(a)(2)(D)(i)
III. Requirements for Regional Haze SIPs
    A. The CAA and the Regional Haze Rule
    B. Best Available Retrofit Technology
IV. BART Determination for AEP/PSO Northeastern Power Station
    A. Oklahoma's Revised BART Determination for AEP/PSO
Northeastern Power Station
    B. EPA's Assessment of the State's Revised BART Determinations
for Units 3 and 4
V. Oklahoma's Interstate Transport Visibility SIP Provisions
VI. What action is EPA proposing?
    A. Regional Haze
    B. Interstate Transport and Visibility
    C. FIP Amendments
    D. Clean Air Act Section 110(l)
VII. Statutory and Executive Order Reviews

I. Background on the Oklahoma Regional Haze SIP and FIP

    The ODEQ submitted a Regional Haze SIP (Oklahoma RH SIP) on
February 19, 2010 to address the requirements of the regional haze
program at 40 CFR 51.308 for the first implementation period. In
December 2011, we partially approved, partially disapproved, and took
no action on various portions of this SIP submittal (76 FR 81727,
December 28, 2011). Even as significant portions of the Oklahoma RH SIP
submittal were approved, we disapproved ODEQ's BART determinations for
SO2 emissions from six coal-fired electric generating units
(EGUs): Units 4 and 5 of the OG&E Muskogee plant, Units 1 and 2 of the
OG&E Sooner plant, and Units 3 and 4 of the AEP/PSO Northeastern Power
Station. Related to these disapprovals, we also disapproved a portion
of a revision to the Oklahoma RH SIP that was submitted to address the
requirements of CAA Section 110(a)(2)(D)(i)(II) as it applies to
visibility for the 1997 8-hour ozone and 1997 fine particulate matter
National Ambient Air Quality Standards (NAAQS). Specifically, this
disapproval found that the SIP submittal had not prevented
SO2 emissions from above-named units from interfering with
visibility programs in other states. Concurrent with these final
disapprovals, we promulgated a FIP that requires SO2
emission limits on the six above-named units to address deficiencies
identified with the BART determinations of the SIP submittal.
    Subsequent to this action, stakeholders, including AEP/PSO, ODEQ,
and EPA, entered into discussions on the development and submittal of a
revised SIP (Oklahoma RH SIP revision) designed to address BART
requirements for Units 3 and 4 of the AEP/PSO Northeastern Power
Station for SO2 and NOX and allow for withdrawal
of FIP requirements for controls of SO2 that are applicable
to those units.\1\ On June 20, 2013, ODEQ

submitted a revised BART determination for Units 3 and 4 of the
Northeastern Power Station for SO2 and NOX and a
related revision to the SIP addressing requirements to prevent
interstate transport of emissions from interfering with other States'
plans to address visibility impairment. The state's revised enforceable
SO2 and NOX BART requirements for Units 3 and 4
of the Northeastern Power Station are contained in the submitted
``First Amended Regional Haze Agreement, DEQ Case No. 10-025 (March
2013)'' that revises the previously submitted ``PSO Regional Haze
Agreement, DEQ Case No. 10-025 (February 10, 2010 \2\)'' We find that
the submitted SIP revision meets the completeness criteria in 40 CFR,
Part 51, Appendix V, which must be met before formal EPA review.
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    \1\ The state of Oklahoma and AEP/PSO filed petitions for review
of the FIP, and the parties have separately entered into a
settlement agreement which includes a timeline for preparing and
processing the SIP revision submitted and reviewed in today's
proposal. A copy of the settlement agreement may be found in
Appendix I of the submitted SIP revision. The settlement agreement
does not dictate what EPA will propose or finally determine with
respect to the submitted SIP revision; today's proposal is based on
our statutorily prescribed role of reviewing the submitted SIP
revision for consistency with the requirements of the Clean Air Act.
    \2\ In our final action on the Oklahoma RH SIP on December 28,
2011, (76 FR 81727), we approved BART determinations and, where
relevant, emission limitations (except those limitations proposed as
SO2 BART for Northeastern Units 3 and 4) for several AEP/
PSO units: Comanche Power Station; Southwestern Power Station; and
Northeastern Power Station. The pertinent emission limitations for
these AEP/PSO units, including the revised BART limits for
Northeastern Power Station Units 3 and 4 that we today propose to
approve, are found in the PSO Regional Haze Agreement, DEQ Case No.
10-025 (February 10, 2010) as amended by the First Amended Regional
Haze Agreement, DEQ Case No. 10-025 (March 2013). Consistent with
today's proposal and to better clarify our past approvals and the
federal enforceability of the limits for these AEP/PSO units and
facilities, we today propose to codify our approval of the agreed
upon order, as amended.
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    This Federal Register notice concerns EPA's review and proposed
approval of the Oklahoma RH SIP Revision affecting the SO2
and NOX BART emission limits applying to AEP/PSO's
Northeastern Units 3 and 4 and the Interstate Transport SIP
requirements, and our proposed withdrawal of source-specific regulatory
requirements for Northeastern Units 3 and 4 that currently apply under
the FIP.

II. Background for EPA's Proposed Action

    In the CAA Amendments of 1977, Congress established a program to
protect and improve visibility in the national parks and wilderness
areas. See CAA section 169A. Congress amended the visibility provisions
in the CAA in 1990 to focus attention on the problem of regional haze.
See CAA section 169B. We promulgated regulations in 1999 to implement
sections 169A and 169B of the Act. These regulations require states to
develop and implement plans to ensure reasonable progress toward
improving visibility in mandatory Class I Federal areas \3\ (Class I
areas) by reducing emissions that cause or contribute to regional
haze.\4\
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    \3\ Areas designated as mandatory Class I Federal areas consist
of national parks exceeding 6,000 acres, wilderness areas and
national memorial parks exceeding 5,000 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 (FLM).'' 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.''
    \4\ See 64 FR 35714 (July 1, 1999); see also 70 FR 39104 (July
6, 2005) and 71 FR 60612 (October 13, 2006).
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A. Definition of Regional Haze

    Regional haze is impairment of visual range or colorization caused
by emissions of air pollution produced by numerous sources and
activities, located across a broad regional area. The sources include,
but are not limited to, major and minor stationary sources, mobile
sources, and area sources, including non-anthropogenic sources.
Visibility impairment is primarily caused by fine particulate matter
(PM2.5) or secondary aerosols formed in the atmosphere from
precursor gases (e.g., SO2, NOX, and in some
cases, ammonia and volatile organic compounds). Atmospheric fine
particulate matter reduces clarity, color, and visual range of scenic
areas. Visibility-reducing fine particulate matter is primarily
composed of sulfates, nitrates, organic carbon compounds, elemental
carbon, and soil dust, and impairs visibility by scattering and
absorbing light. Fine particulate matter can also cause serious health
effects and mortality in humans, and contributes to environmental
effects such as acid rain deposition and eutrophication.\5\
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    \5\ See 64 FR 35715.
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    Data from the existing visibility monitoring network, the
``Interagency Monitoring of Protected Visual Environments'' (IMPROVE)
monitoring network, show that visibility impairment caused by air
pollution occurs virtually all the time at most national parks and
wilderness areas. Average visual range in many Class I areas in the
Western United States is 100-150 kilometers, or about one-half to two-
thirds the visual range that would exist without man-made air
pollution.\6\ Visibility impairment also varies day-to-day and season-
to-season depending on variations in meteorology and emission rates.
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    \6\ Id.
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B. Regional Haze Rules and Regulations

    In section 169A of the 1977 CAA Amendments, Congress created a
program for protecting visibility in the nation's national parks and
wilderness areas. This section of the CAA establishes as a national
goal the ``prevention of any future, and the remedying of any existing,
impairment of visibility in Class I areas, which impairment results
from man-made air pollution.'' \7\ On December 2, 1980, we 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.'' \8\
These regulations represented the first phase in addressing visibility
impairment. We deferred action on regional haze that results from
emissions 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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    \7\ See CAA section 169A(a)(1).
    \8\ See 45 FR 80084.
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    Congress added section 169B to the CAA in 1990 to further address
regional haze issues. We promulgated a rule to address regional haze on
July 1, 1999 (64 FR 35713) (the Regional Haze Rule or RHR). The RHR
revised the existing visibility regulations by adding provisions that
address regional haze impairment and that establish 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 our
visibility protection regulations at 40 CFR 51.300-309. Some of the
main elements of the regional haze requirements are summarized in
section III of this rulemaking. The requirement to submit a regional
haze SIP applies to all 50 states, the District of Columbia, and the
Virgin Islands.\9\ Pursuant to 40 CFR 51.308(b), states were required
to submit the first implementation plan addressing regional haze
visibility impairment no later than December 17, 2007.
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    \9\ Albuquerque/Bernalillo County in New Mexico must also submit
a regional haze SIP to completely satisfy the requirements of
section 110(a)(2)(D) of the CAA for the entire State of New Mexico
under the New Mexico Air Quality Control Act (section 74-2-4).

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C. 1997 NAAQS for Ozone and PM2.5 and CAA Section
110(a)(2)(D)(i)

    On July 18, 1997, we promulgated new NAAQS for 8-hour ozone and
PM2.5.\10\ Section 110(a)(1) of the CAA requires states to
submit SIPs to address a new or revised NAAQS within three years after
promulgation of such standards, or within such shorter period as we may
prescribe. Section 110(a)(2) of the CAA lists the elements that such
new SIPs must address, as applicable, including section
110(a)(2)(D)(i), which pertains to the interstate transport of certain
emissions.
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    \10\ See 62 FR 38652.
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    On April 25, 2005, we published a ``Finding of Failure to Submit
SIPs for Interstate Transport for the 8-hour Ozone and PM2.5
NAAQS.'' \11\ This action included a finding that Oklahoma and other
states had failed to submit SIPs for interstate transport of air
pollution affecting visibility and started a two-year clock for the
promulgation of a FIP, unless a state made a submission to meet the
requirements of section 110(a)(2)(D)(i) and we approved the submission
before promulgating a FIP.
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    \11\ See 70 FR 21147.
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    On August 15, 2006, we issued our ``Guidance for State
Implementation Plan (SIP) Submissions to Meet Current Outstanding
Obligations Under Section 110(a)(2)(D)(i) for the 8-Hour Ozone and
PM2.5 National Ambient Air Quality Standards'' (2006
Guidance). We developed the 2006 Guidance to make recommendations to
states for making submissions to meet the requirements of section
110(a)(2)(D)(i) for the 1997 8-hour ozone standards and the 1997
PM2.5 standards.
    As identified in the 2006 Guidance, the ``good neighbor''
provisions in section 110(a)(2)(D)(i) of the CAA require each state to
submit a SIP that prohibits emissions that adversely affect another
state in the ways contemplated in the statute. Section 110(a)(2)(D)(i)
contains four distinct requirements related to the impacts of
interstate transport. The SIP must prevent sources in the state from
emitting pollutants in amounts which will: (1) Contribute significantly
to nonattainment of the NAAQS in other states; (2) interfere with
maintenance of the NAAQS in other states; (3) interfere with provisions
to prevent significant deterioration of air quality in other states; or
(4) interfere with efforts to protect visibility in other states.
    The 2006 Guidance stated that states may make a simple SIP
submission confirming that it is not possible at that time to assess
whether there is any interference with measures in the applicable SIP
for another state designed to ``protect visibility'' for the 8-hour
ozone and PM2.5 NAAQS until Regional Haze SIPs are submitted
and approved. These SIPs were required to be submitted by December 17,
2007.\12\
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    \12\ See 74 FR 2392 (January 15, 2009).
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    On May 10, 2007, we received a SIP revision submitted to address
the interstate transport provisions of CAA 110(a)(2)(D)(i) for the 1997
ozone and 1997 PM2.5 NAAQS (Oklahoma Interstate Transport
SIP). We received a supplement to this SIP revision on December 10,
2007. In a prior action, we partially approved the submitted Oklahoma
Interstate Transport SIP for the ``interfere with measures to prevent
significant deterioration'' prong of section 110(a)(2)(D)(i) of the
CAA.\13\ On February 19, 2010, Oklahoma submitted the Oklahoma RH SIP
to address interstate transport of emissions that could interfere with
efforts to protect visibility in other states. Because we could only
partially approve the Oklahoma RH SIP submittal, we issued a partial
approval and partial disapproval of the Oklahoma Interstate Transport
SIP that addressed the requirement that emissions from Oklahoma sources
do not interfere with measures required in the SIP of any other state
to protect visibility and concurrently issued a FIP to address defects
in the Oklahoma Interstate Transport SIP submission.
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    \13\ See 75 FR 72695 (November 26, 2010).
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III. Requirements for Regional Haze SIPs

A. The CAA and the Regional Haze Rule

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

B. 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 \14\ built between 1962 and 1977 procure, install, and operate
the ``Best Available Retrofit Technology'' as determined by the state.
States are directed to conduct BART determinations for such sources
that may be anticipated to cause or contribute to any visibility
impairment in a Class I area. Rather than requiring source-specific
BART controls, states also have the flexibility to adopt an emissions
trading program or other alternative program as long as the alternative
program provides greater reasonable progress towards improving
visibility than BART.
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    \14\ The set of ``major stationary sources'' potentially subject
to BART is listed in CAA section 169A(g)(7).
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    On July 6, 2005, we published the Guidelines for BART
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR
Part 51 (henceforth 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.\15\ In making a BART applicability
determination for a fossil fuel-fired electric generating plant with a
total generating capacity in excess of 750 megawatts, a state must use
the approach set forth in the BART Guidelines. A State is encouraged,
but not required, to follow the BART Guidelines in making BART
determinations for other types of sources. Regardless of source size or
type, however, a state must meet the CAA and regulatory requirements
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.
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    \15\ 70 FR 39104.
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    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
PM2.5. The EPA has indicated that states should use their
best judgment in determining whether emissions of volatile organic
compounds or compounds of ammonia contribute to impairment of
visibility in Class I areas.
    Under the BART Guidelines, States may select and document an
exemption threshold value to determine those BART-eligible sources not
subject to

BART. A BART-eligible source with an impact below the threshold value
would not be expected to cause or contribute to visibility impairment
in any Class I area. Any source with emissions great enough to result
in a visibility impact above the threshold value would be subject to a
BART determination review. The BART Guidelines acknowledge varying
circumstances affecting different Class I areas. States should consider
the number of emission sources affecting the Class I areas at issue and
the magnitude of the individual sources' impacts. Generally, an
exemption threshold set by the State should not be higher than 0.5
deciviews (dv).
    In their SIPs, States must identify BART-eligible sources that have
a visibility impact in any Class I area above the ``BART-subject''
exemption threshold established by the State and thus, are subject to
BART. States must document their BART control analysis and
determination for all sources subject to BART.
    The term ``BART-eligible source'' used in the BART Guidelines means
the collection of individual emission units at a facility that together
comprises the BART-eligible source. In making a BART determination,
section 169A(g)(2) of the CAA requires that States consider the
following factors: (1) The costs of compliance, (2) the energy and non-
air quality environmental impacts of compliance, (3) any existing
pollution control technology in use at the source, (4) the remaining
useful life of the source, and (5) the degree of improvement in
visibility which may reasonably be anticipated to result from the use
of such technology.\16\
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    \16\ See 40 CFR 51.308(e)(1)(ii)(A).
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    Each state's 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 the EPA approves the regional
haze SIP.\17\ 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 that pertain to a source. States have the flexibility
to choose the type of control measures they will ultimately use to meet
the BART emission limits.
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    \17\ See CAA section 169(g)(4) and 40 CFR 51.308(e)(1)(iv).
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IV. BART Determination for AEP/PSO Northeastern Power Station

A. Oklahoma's Revised BART Determination for the AEP/PSO Northeastern
Power Station

    In our prior review and action on the Oklahoma RH SIP, we agreed
with Oklahoma's identification of sources that are BART-eligible and
subject to BART, including Units 3 and 4 of the AEP/PSO Northeastern
Power Station. 76 FR 81727 (December 28, 2011). We approved the State's
PM and NOX BART determinations and emission limits for these
two units, with the pertinent emissions limitations contained in the
PSO Regional Haze Agreement, DEQ Case No. 10-025 (February 10, 2010),
while disapproving the State's SO2 BART determinations and
emission limits.\18\ Specifically, we approved the NOX BART
emission limits of 0.15 lb/MMBtu (based on 30-day rolling averages) for
Units 3 and 4 and disapproved the SO2 BART determinations of
no additional controls for Units 3 and 4. We promulgated an
SO2 BART emission limit of 0.06 lb/MMBtu for each unit
(based on rolling 30 boiler operating day averages).
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    \18\ We note again that with today's proposal that we propose to
codify our approval of this agreed-upon order, as amended, because
it will confirm and clarify our past approvals as well as the
emission limitations and related schedules for the BART
determinations we propose to approve today.
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NOX BART
    The Oklahoma RH SIP Revision explains that it ``does not reopen
[the prior and EPA-approved] NOX technology determination,
but does require earlier installation and compliance with reduced
emission limits prior to the original SIP-imposed deadline.'' Oklahoma
RH SIP Revision, Appendix 2 at 12. Our prior approval of NOX
BART for Unit 3 and 4 required that these units meet a NOX
emission limit of 0.15 lb/MMBtu (based on a 30-day rolling average)
within five years from the effective date of EPA's approval, or by
January 27, 2017. However, under the Oklahoma RH SIP Revision, both
units are now required to meet an initial NOX emission limit
of 0.23 lb/MMBtu (based on a 30-day rolling average) by December 31,
2013, with additional limits of 1,098 lb/hr per unit on a 30-day
rolling average basis and a 9,620 tpy combined cap for both units. By
April 16, 2016, one unit is required to be permanently shut down, while
the remaining unit is required to meet a NOX emission limit
of 0.15 lb/MMBtu (based on a 30-day rolling average), with an
additional limit of 716 lb/hr on a 30-day rolling average basis and a
cap of 3,137 tpy on a 12-month rolling basis. Finally, this second unit
is required to shut down by December 31, 2026. These emission limits
and shutdowns are made enforceable by the submitted ``First Amended
Regional Haze Agreement, DEQ Case No. 10-025 (March 2013)'' that
revises the previously submitted ``PSO Regional Haze Agreement, DEQ
Case No. 10-025 (February 10, 2010). This revised NOX BART
determination is more stringent than the determination that we
previously approved because it requires compliance with the 0.15 lb/
MMBtu limit on a more expeditious schedule.
SO2 BART
    The Oklahoma RH SIP Revision also includes a new SO2
BART determination for Units 3 and 4, which differs from both
Oklahoma's original SO2 BART determination of no new
controls and our SO2 BART emission limit of 0.06 lb/MMBtu,
which can be met by the installation of Dry Flue Gas Desulfurization/
Spray Dryer Absorber technology (DFGD/SDA). Oklahoma's new
SO2 BART determination contains several elements, including
interim emission limits, the installation of Dry Sorbent Injection
(DSI) technology and a fabric filter baghouse, phased reductions in
capacity utilization, and enforceable deadlines by which Units 3 and 4
must be shut down entirely. As a consequence, the ``remaining useful
life'' of Units 3 and 4 was an important consideration in Oklahoma's
new SO2 BART determination. Specifically, the Oklahoma RH
SIP revision requires the following:
     By January 31, 2014, Units 3 and 4 must comply with an
emission limit of 0.65 lb/MMBtu on a 30-day rolling average basis, to
be met through the use of low-sulfur coal. An additional limit of 3,104
lb/hr on a 30-day rolling average basis will also apply to each unit;
     By December 31, 2014, Units 3 and 4 must comply with a
reduced emission limit of 0.60 lb/MMBtu on a 12-month rolling average
basis and a combined emissions cap of 25,097 tons/year on a 12-month
rolling basis;
     By April 16, 2016, one of the two units must be
permanently shut down, while the remaining unit must comply with a
reduced emission limit of 0.4 lb/MMBtu \19\ (based on DSI) \20\ on a
30-day

rolling average basis. Additional limits of 1,910 lb/hr on a 30-day
rolling average basis and 8,366 tons per year on a 12-month rolling
basis will also apply;
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    \19\ The company is also required to optimize the performance of
the DSI through implementation of a testing protocol at varying
operational parameters. If a lower limit is achievable, the company
will have to revise its permit limits.
    \20\ ODEQ notes that the installation of DSI will necessitate
the addition of a fabric filter baghouse to further control PM
emissions. ODEQ explains that, despite the installation of this
baghouse for the purposes of accommodating DSI, ODEQ is not re-
opening its determination in the original Oklahoma RH SIP that no
further controls are required to satisfy PM BART. See Oklahoma RH
SIP Revision, Appendix 2 at 3.
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     The capacity utilization of the remaining unit will be
capped at 70 percent by January 1, 2021; 60 percent by January 1, 2023;
and 50 percent by January 1, 2025; and
     The remaining unit must be permanently shut down by
December 31, 2026.
    In its BART analysis, ODEQ identified its DSI/shutdown proposal as
one control option and the FIP scenario of two DFGD/SDA systems as the
second control option.\21\ In accordance with section 169A of the CAA,
the RHR, and the BART Guidelines, ODEQ weighed the five statutory
factors in comparing its new proposal against our FIP. After factoring
in a ten-year amortization period for DSI (due to the shutdown of the
second unit in 2026), ODEQ determined that DSI would have an average
cost-effectiveness of $1,005/ton, while the installation of two DFGD/
SDA systems, as contemplated by EPA's FIP, had an average cost-
effectiveness of $1,544/ton. ODEQ further noted that the incremental
cost-effectiveness of the DSI/shutdown scenario versus the FIP scenario
was $4,718/ton in the first year, with worsening incremental cost-
effectiveness as the capacity utilization of the remaining unit
decreased starting in 2021.
---------------------------------------------------------------------------

    \21\ ODEQ declined to re-evaluate wet scrubbers because EPA had
previously determined that the emission limit achievable by this
control option was not BART in our FIP. While the BART Guidelines
require states to evaluate all technically feasible control options
when making a BART determination, we believe that ODEQ was justified
in eliminating wet scrubbers based on our prior analysis in this
instance.
---------------------------------------------------------------------------

    ODEQ also conducted a revised visibility modeling analysis using
CALPUFF. ODEQ found that, while two DFGD/SDA systems provided the
greatest visibility improvement across all Class I areas, the
incremental visibility improvement between the DSI/shutdown scenario
and the FIP scenario was small. ODEQ concluded that the FIP scenario
would result in approximately 0.1 dv of additional visibility
improvement compared with the DSI/shutdown scenario at each impacted
Class I area, with a total additional improvement of approximately 0.27
dv across all four of the nearest Class I areas.
    ODEQ noted that the DSI/shutdown scenario would result in
additional reductions of NOX beyond the NOX FIP
level and additional reductions of other air pollutants, such as PM,
and CO2e, thereby helping to address local formation and
interstate transport of ozone and reducing Oklahoma's contribution to
greenhouse gases. Finally, ODEQ considered the non-air quality impacts
of DSI/shutdown scenario and found that it would require less water
usage, reduce mercury deposition, and reduce approximately half of the
energy consumption as the FIP scenario. Given the comparable visibility
improvement, lower costs, and overall reduced environmental impact,
ODEQ concluded that the DSI/shutdown scenario was SO2 BART.

B. EPA's Assessment of the State's Revised BART Determinations for
Units 3 and 4

NOX BART
    Oklahoma's revised NOX BART determination for Units 3
and 4 does not require us to revisit our earlier approval of the
State's NOX BART determination for these units, but only to
review a faster compliance schedule. Sources that are subject to BART
must install and operate those controls ``as expeditiously as
practicable but in no event later than five years after the date of
approval of a plan revision . . .'' CAA section 169A(g)(4). Here,
Oklahoma has determined that the NOX BART limits for Units 3
and 4 that we previously approved can be complied with more
expeditiously than previously required. Early implementation of the
NOX BART limits will provide improvements in visibility
sooner, thus making the Oklahoma RH SIP more stringent. We therefore
propose to approve this part of the Oklahoma RH SIP Revision and find
that it meets the requirements of the CAA. We also propose to codify,
in the approved SIP, the ``PSO Regional Haze Agreement, DEQ Case No.
10-025 (February 10, 2010)'' as amended by the ``First Amended Regional
Haze Agreement, DEQ Case No. 10-025 (March 2013)'' because they contain
NOx BART emission limitations and schedules for the AEP/PSO two units
found therein.
SO2 BART
    The CAA defines a FIP as ``a plan (or portion thereof) promulgated
by the Administrator to fill all or a portion of a gap or otherwise
correct all or a portion of an inadequacy in a [SIP].'' CAA section
302(y). Because a FIP is intended as a gap-filling measure, EPA
encourages states to submit approvable SIP revisions that correct the
deficiencies that a given FIP remedied. Such a SIP revision need not
adopt the same suite of control options and techniques as EPA's FIP,
nor does it necessarily have to be as stringent as EPA's FIP in all
instances. Rather, when a State submits a SIP revision to EPA with the
intention of replacing a FIP, EPA must approve the SIP revision so long
as the SIP revision does not ``interfere with any applicable
requirement concerning attainment and reasonable further progress . . .
or any other applicable requirement of [the Act].'' CAA section 110(l).
In regards to regional haze SIPs and the statutory requirement to make
BART determinations for certain older major stationary sources, EPA
must approve a State's SIP revision so long as the State complies with
the CAA's visibility protection provisions, the RHR, and the BART
Guidelines, and makes a reasonable control determination based on the
weighing of the five factors. We have analyzed Oklahoma's new
SO2 BART determination with these requirements in mind.
    We propose to conclude that ODEQ has appropriately met the
requirements of 40 CFR 308(e) and the BART Guidelines of Appendix Y in
determining BART for emissions of SO2 from AEP/PSO
Northeastern Power Station Units 3 and 4. This conclusion is based on
our review of ODEQ's SIP submittal, including the original February 19,
2010 Regional Haze Submittal and the June 2013 SIP revision.
    ODEQ's revised BART determination includes the shutdown of one of
the two units in April 2016 and the second unit in December 2026, so
the controlling facts for the BART analysis are different than the
facts that were presented with Oklahoma's 2010 SIP submission. As
discussed previously, in the 2013 SIP revision ODEQ determined that the
DSI/shutdown scenario was SO2 BART for AEP/PSO Northeastern
Power Station Units 3 and 4. ODEQ made this determination based on an
analysis of the five BART factors and other information. Their analysis
of the five BART factors included consideration of the high incremental
cost-effectiveness and low incremental visibility improvement between
the FIP and DSI/shutdown scenarios, as well as the additional non-air
quality environmental and energy benefits of the latter. The energy and
non-air quality environmental impacts, e.g., reductions in mercury
deposition, water and energy usage, associated with the DSI/shutdown
scenario support the conclusion that the shutdown/DSI

option is BART.\22\ ODEQ also considered the additional air quality
benefits associated with shutting down Units 3 and 4 which, while
important, these other air quality benefits such as reduced ozone and
PM formation and CO2e are not among the BART factors.
---------------------------------------------------------------------------

    \22\ [T]he State must take into consideration the technology
available, the costs of compliance, the energy and non-air quality
environmental impacts of compliance, any pollution control equipment
in use at the source, the remaining useful life of the source, and
the degree of improvement in visibility which may reasonably be
anticipated to result from the use of such technology. 40 CFR
51.308(e)(1)(ii)(A).
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    Regarding the other BART factors, while BART determinations are
typically made on a unit-by-unit basis, we believe that ODEQ's decision
to evaluate BART on a facility-wide basis is a reasonable way to take
into account the visibility and energy and non-air quality
environmental benefits associated with unit shutdowns. While we believe
ODEQ's facility wide approach to BART is reasonable, we have also
analyzed BART on a unit by unit analysis. A unit by unit analysis
includes the consideration of a scenario, not considered by ODEQ, in
which the unit that remains in operation after April 16, 2016 installs
DFGD/SDA. We also made adjustments to ODEQ's cost and visibility
calculations to take into account more recent information regarding the
facilities baseline ``uncontrolled'' emissions and the useful life of
the facility. The adjustments were necessary to properly assess the
cost and visibility factors on a unit by unit basis but were less
important when the analysis was conducted, as ODEQ did, on a facility
wide basis. First, we re-calculated cost-effectiveness assuming a
baseline emission rate of 0.6 lb/MMBtu instead of the 0.9 lb/MMBtu rate
used by ODEQ. The 0.6 lb/MMBtu emission rate takes into account more
recent information regarding the actual emissions of Units 3 and 4 and
it is more representative of the emission limits Oklahoma requires the
two units to meet beginning January 31, 2014. In addition, based on the
enforceable shutdown deadline, we assumed an amortization period of ten
years for both DSI and DFGD/SDA. We used the same heat input of 4,775
MMBtu/hr and 85% capacity factor as ODEQ.
    We calculated that the average cost-effectiveness of the DSI/
shutdown scenario would be $1,758/ton, while the average cost-
effectiveness of the DFGD/SDA/shutdown scenario would be $3,211/ton.
The incremental cost-effectiveness of installing DFGD/SDA as the BART
control on the remaining unit rather than DSI would be $7362/ton. See
our TSD for more details of our cost analysis. A spreadsheet containing
this EPA calculated cost effectiveness of DFGD/SDA is contained in the
docket, and a summary of this information is presented in Table 1of the
Technical Support Document accompanying this proposed action.
    We reviewed the CALPUFF visibility modeling in the proposed SIP
revision submittal and also performed additional analyses (including
additional CALPUFF model runs). Please see the SIP's Appendix II and
EPA's Technical Support Document for more details of AEP/PSO's
modeling, ODEQ's evaluation, and EPA's modeling and evaluation. While,
as described in the TSD, the Oklahoma's modeling has some differences
from ours, the relative results are similar and the differences are not
such that it changes our overall conclusions. In addition to the
scenarios considered by Oklahoma, we also considered the scenario of
one unit shutting down and one unit with DFGD/SDA. While we did not
model this scenario, it is reasonable to approximate this scenario
would result in one half the visibility impairment of the FIP scenario
of two units operating with DFGD/SDA. Based on this assumption, this
scenario results in an improvement of 0.19 deciviews at the most
impacted Class I area and 0.64 deciviews cumulatively, when compared to
DSI on the remaining operating unit. As discussed above, this
visibility benefit is achieved at relatively high incremental cost
effectiveness.
    Oklahoma found, and we agree, that the DFGD/SDA scenario in the FIP
would only result in slightly more visibility benefit than Oklahoma's
chosen BART determination in which one unit operates until 2026 using
DSI. A unit by unit analysis reveals that additional visibility benefit
can be achieved if the unit that remains in operation were to implement
DFGD/SDA, but this visibility benefit is achieved at a relatively high
incremental cost.
    In summary, we believe that when incremental costs, energy and non-
air quality impacts, and the remaining useful life of the source are
taken into consideration, ODEQ's determination that DSI is the proper
BART control for the remaining unit is ultimately reasonable. We
therefore propose to approve ODEQ's new SO2 BART
determination in full and propose to rescind the emission limits and
compliance schedule contained in our FIP.
    Previously, we disapproved the ``PSO Regional Haze Agreement, DEQ
Case No. 10-025 (February 10, 2010),'' and its emission limitations for
SO2. With today's proposed approval of the state's BART
determinations, as revised, we now propose to approve the ``PSO
Regional Haze Agreement, DEQ Case No. 10-025 (February 10, 2010)'' as
amended by the ``First Amended Regional Haze Agreement, DEQ Case No.
10-025 (March 2013),'' and the SO2 BART emission limitations
for the two AEP/PSO units found therein.

V. Oklahoma's Interstate Transport Visibility SIP Provisions

    Oklahoma submitted its Interstate Transport SIP for an Assessment
of Oklahoma's Impact on Downwind Nonattainment for the National Ambient
8-hour Ozone and PM2.5 Air Quality Standards (``Transport SIP'') to EPA
in May 2007 and submitted supplemental information in December 2007.
Our December 28, 2011 action on the Oklahoma RH SIP also addressed the
provisions of the Oklahoma Interstate Transport SIP relating to
visibility protection. In that action, we partially approved and
partially disapproved the Oklahoma Interstate Transport SIP, which
relied in part upon the Oklahoma RH SIP to satisfy the requirements of
CAA section 110(a)(2)(D)(i)(II), because we could only partially
approve the Oklahoma RH SIP. We also promulgated an Interstate
Transport FIP for visibility requiring source-specific SO2
emission limitations.
    As an initial matter, we note that CAA section 110(a)(2)(D)(i)(II)
does not explicitly specify how we should ascertain whether a state's
SIP contains adequate provisions to prevent emissions from sources in
that state from interfering with measures required in another state to
protect visibility. Thus, the statute is ambiguous on its face, and we
must interpret that provision in a reasonable fashion. Our 2006
Guidance recommended that a state could meet the visibility prong of
CAA section 110(a)(2)(D)(i)(II) by submitting a fully approvable
regional haze SIP. We reasoned that the development of the regional
haze SIPs involved collaboration among the states. In fact, in
developing their respective reasonable progress goals, CENRAP states
consulted with each other through CENRAP's work groups. As a result of
this process, the common understanding was that each state would take
action to achieve the emissions reductions relied upon by other states
in their reasonable progress demonstrations. CENRAP states consulted in
the development of reasonable progress goals, using the products of the
technical consultation

process to co-develop their reasonable progress goals. In developing
their visibility projections using photochemical grid modeling, CENRAP
states assumed a certain level of emissions from sources within
Oklahoma. This modeling assumed SO2 reductions from AEP/PSO
Northeastern Power Station Units 3 and 4. We understand that the CENRAP
states used the visibility projection modeling to establish their own
respective reasonable progress goals. Thus, we believe that an
implementation plan that provides for emissions reductions consistent
with the assumptions used in those states' modeling will ensure that
emissions from Oklahoma sources do not interfere with the measures
designed to protect visibility in other states.
    In the case of Northeastern Units 3 and 4, the CENRAP modeling
assumed that each of these units would achieve the presumptive limit of
0.15 lb/MMBtu by 2018. Under the Oklahoma RH SIP Revision, one of the
two units is required to shut down before that date, while the
remaining unit is required to install DSI. To achieve emission levels
equivalent to the levels assumed in other States' Regional Haze plans,
the remaining unit must would have to meet an emission limit of 0.3 lb/
MMBtu (0.15 + 0.15) by 2018. Currently, the First Amended Regional Haze
Agreement in the submitted SIP revision only requires the remaining
unit to meet an emission limit of 0.4 lb/MMBtu. However, the First
Amended Regional Haze Agreement also requires the source operators to
optimize the performance of DSI on the remaining unit to ensure that
the best possible performance is achieved and adjust the limit
accordingly. Further, if the remaining operating unit still cannot meet
the emission limit of 0.3 lb/MMBtu, then the Oklahoma RH SIP Revision
contains an enforceable commitment on behalf of ODEQ to ``obtain and/or
identify additional SO2 reductions within the State of
Oklahoma to the extent necessary to achieve the anticipated visibility
benefits estimated'' by CENRAP. For example, any additional
SO2 emissions reductions that can be obtained or identified
from the northeast quadrant of the State will be presumed to count
toward the emission reductions necessary to achieve the anticipated
visibility benefits associated with a 0.30 lb/MMBtu emission limit at
Northeastern. Emissions reductions obtained outside the northeast
quadrant that are technically justified will also be counted. Finally,
if necessary, additional emissions reductions shall be obtained via
enforceable emission limits or control equipment requirements where
necessary and submitted to EPA as a SIP revision as expeditiously as
practicable, but in no event later than the end of the first full
Oklahoma legislative session occurring subsequent to AEP/PSO's
submission of the evaluation and report required by Paragraph 1(f) of
Attachment A of the AEP/PSO Settlement Agreement presented in Appendix
I of the 2013 SIP Submission. Moreover, any additional reductions that
are obtained prior to the 2018 Regional Haze SIP revision required by
40 CFR Sec.  51.308(f) but not accounted for in the above referenced
modeling will be identified in the 2018 revision.
    Therefore, if the SO2 emission rate for the remaining
coal-fired unit is not reduced to 0.30 lb/MMBtu after the
implementation of the control requirements required by the First
Amended Regional Haze Agreement, then there will not be the emissions
reductions relied upon in the CENRAP modeling. These emission
reductions must be obtained from elsewhere to meet the requirements of
the Visibility Interstate Transport SIP/FIP. We are proposing to find
that the state already has provided the majority of required emissions
reductions for the Visibility interstate transport statutory
requirement. The balance of the needed reductions is in the form of
enforceable commitments from the ODEQ. We believe, consistent with past
practice, that the CAA allows for the approval of enforceable
commitments that are limited in scope where circumstances exist that
warrant the use of such commitments in place of adopted measures.\23\
Once we determine that circumstances warrant consideration of an
enforceable commitment, we consider three factors in determining
whether to approve the enforceable commitment: (a) Does the commitment
address a limited portion of the statutorily-required program; (b) is
the state capable of fulfilling its commitment; and (c) is the
commitment for a reasonable and appropriate period of time.\24\
Oklahoma has met these criteria because the enforceable commitment
addresses only a small potential shortfall in the emission reductions
necessary to ensure that the State's SIP will not interfere with other
states' plans to protect visibility. Under the DSI/shutdown scenario,
the Northeastern Power Station will achieve at least 70% of the
approximately 75% reduction in SO2 emissions necessary to
meet the level projected in the CENRAP modeling (based on a baseline of
0.6 lb/MMBtu). Further, this is only a possible shortfall, as the
facility is required to optimize the performance of the DSI and may
well be able to achieve further reductions. Oklahoma is capable of
fulfilling its commitment because it has the authority to adopt
measures if necessary and likely will be able to identify federally
enforceable reductions through other measures not anticipated in CENRAP
modeling, such as EPA's Modeled Attainment Test Software (MATS).
Finally, we believe that Oklahoma has committed to address any
shortfall as expeditiously as practical given the time needed for the
source to conduct the optimization study and for ODEQ to complete the
State's SIP adoption process.
---------------------------------------------------------------------------

    \23\ Commitments approved by EPA under section 110(k)(3) of the
CAA are enforceable by EPA and citizens under, respectively,
sections 113 and 304 of the CAA. In the past, EPA has approved
enforceable commitments and courts have enforced these actions
against states that failed to comply with those commitments: See,
e.g., American Lung Ass'n of N.J. v. Kean, 670 F. Supp. 1285 (D.N.J.
1987), aff'd, 871 F.2d 319 (3rd Cir. 1989); NRDC, Inc. v. N.Y. State
Dept. of Env. Conservation, 668 F. Supp. 848 (S.D.N.Y. 1987);
Citizens for a Better Env't v. Deukmejian, 731 F. Supp. 1448, recon.
granted in par, 746 F. Supp. 976 (N.D. Cal. 1990); Coalition for
Clean Air v. South Coast Air Quality Mgmt. Dist., No. CV 97-6916-HLH
(C.D. Cal. Aug. 27, 1999). Further, if a state fails to meet its
commitments, EPA could make a finding of failure to implement the
SIP under CAA Section 179(a), which starts an 18-month period for
the State to correct the non-implementation before mandatory
sanctions are imposed. CAA section 110(a)(2)(A) provides that each
SIP ``shall include enforceable emission limitations and other
control measures, means or techniques . . . as well as schedules and
timetables for compliance, as may be necessary or appropriate to
meet the applicable requirement of the Act.'' Section 172(c)(6) of
the Act, which applies to nonattainment SIPs, is virtually identical
to section 110(a)(2)(A). The language in these sections of the CAA
is quite broad, allowing a SIP to contain any ``means or
techniques'' that EPA determines are ``necessary or appropriate'' to
meet CAA requirements, such that the area will attain as
expeditiously as practicable, but no later than the designated date.
Furthermore, the express allowance for ``schedules and timetables''
demonstrates that Congress understood that all required controls
might not have to be in place before a SIP could be fully approved.
    \24\ The U.S. Court of Appeals for the Fifth Circuit upheld
EPA's interpretation of CAA sections 110(a)(2)(A) and 172(c)(6) and
the Agency's use and application of the three-factor test in
approving enforceable commitments in the Houston-Galveston ozone
SIP. BCCA Appeal Group v. EPA, 355 F.3d 817 (5th Cir. 2003).
---------------------------------------------------------------------------

    In conclusion, we propose to approve the enforceable commitments
made in the Oklahoma RH SIP Revision as satisfying Oklahoma's
interstate transport obligations for visibility. We also propose to
find that the SO2 emissions reductions associated with
Northeastern Units 3 and 4, when combined with the enforceable
commitments, will be consistent with the levels of control assumed in
the

CENRAP modeling and relied on by other states as part of their
reasonable progress demonstrations.

VI. What action is EPA proposing?

A. Regional Haze

    For the reasons explained above, we are proposing to approve ODEQ's
revised SO2 BART determination for Units 3 and 4 of the AEP/
PSO Northeastern Power Station. This revised SO2 BART
determination (and related control measures) includes the following
emission control requirements: (1) By January 31, 2014, the facility
will comply with an interim SO2 emission limit of 0.65 lb/
MMBtu per unit on a 30-day rolling average basis, with an additional
limit of 3,104 lb/hr per unit on a 30-day rolling average basis; (2) by
December 31, 2014, the facility will comply with a reduced interim
SO2 emission limit of 0.60 lb/MMBtu per unit on a 12-month
rolling average basis, with an additional 25,097 tpy combined cap for
Units 3 and 4 on a 12-month rolling basis; (3) the facility will shut
down one of the subject units (either Unit 3 or Unit 4) no later than
April 16, 2016; (4) the facility will install and operate a dry sorbent
injection (DSI) system on the unit that remains in operation past April
16, 2016; (5) the unit remaining in operation will comply with an
SO2 emission limit of 0.40 lb/MMBtu on a 30-day rolling
average basis from April 16, 2016 through December 31, 2026, with
additional limits of 1,910 lb/hr on a 30-day rolling average basis and
8,366 tpy on a 12-month rolling basis (this limit may be lowered
pursuant to the results of an optimization study to be conducted by
AEP/PSO); and (6) the facility will incrementally decrease capacity
utilization for the remaining unit between 2021 and 2026, culminating
with the complete shutdown of the remaining unit no later than December
31, 2026. Consequently, we are proposing to approve for SO2,
the ``PSO Regional Haze Agreement, DEQ Case No. 10-025 (February 10,
2010), as amended by the ``First Amended Regional Haze Agreement, DEQ
Case No. 10-025 (March 2013).''
    The newly submitted regional haze SIP revision also includes, and
we are proposing to approve, an accelerated NOX BART
compliance schedule: (1) By December 31, 2013, the facility will comply
with an emission limit of 0.23 lb/MMBtu on a 30-day rolling average
basis with an additional limit of 1,098 lb/hr per unit on a 30-day
rolling average basis and a 9,620 tpy combined cap for both units; and
(2) the unit that remains in operation shall undergo further control
system tuning and by April 16, 2016 comply with an emission limit of
0.15 lb/MMBtu on a 30-day rolling average basis with an additional
limit of 716 lb/hr on a 30-day rolling average basis and a cap of 3,137
tpy on a 12-month rolling basis. For NOx, we are proposing to codify
our approval of the PSO Regional Haze Agreement, DEQ Case No. 10-025
(February 10, 2010) as amended by the First Amended Regional Haze
Agreement, DEQ Case No. 10-025 (March 2013), because it contains the
NOx BART emission limitations and schedules for AEP/PSO's BART subject
units in Oklahoma.

B. Interstate Transport and Visibility

    Because we are proposing to approve the State's new SO2
BART determination for AEP/PSO Northeastern Power Station Units 3 and
4, we accordingly propose to approve that portion of the Oklahoma RH
SIP Revision concerning Oklahoma's interstate transport obligations,
which we found were not appropriately addressed by the prior,
disapproved submittal. We propose to find that the Oklahoma RH SIP
Revision addresses the requirements of the interstate transport
provisions of CAA section 110(a)(2)(D)(i)(II) as applied to this source
and its associated impacts on other states' programs to protect
visibility in Class I Areas. Relatedly, we propose to approve the
ODEQ's enforceable commitment in the SIP Narrative at page 10.

C. FIP Amendments

    We are proposing to withdraw those portions of the FIP at 40 CFR
Sec.  52.1923 that impose SO2 requirements on AEP/PSO
Northeastern Units 3 and 4.\25\ We note that finalization of this
portion of today's proposal may follow our finalized approval of the
SIP revisions via a separate Administrator-signed action.
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    \25\ The proposed amendatory language for this proposed revision
of the earlier promulgated FIP is set forth at the end of this
proposal. If the action is finalized as proposed, the final action
will also present additional amendatory language reflecting our
approval of the submitted SIP revision.
---------------------------------------------------------------------------

D. Clean Air Act Section 110(l)

    Section 110(l) of the CAA states that ``[t]he Administrator shall
not approve a revision of a plan if the revision would interfere with
any applicable requirement concerning attainment and reasonable further
progress or any other applicable requirement of this chapter.'' 42
U.S.C. 7410(l). EPA does not interpret section 110(l) to require a full
attainment or maintenance demonstration before any changes to a SIP may
be approved. Generally, a SIP revision may be approved under section
110(l) if EPA finds that it will at least preserve status quo air
quality, particularly where the pollutants at issue are those for which
an area has not been designated nonattainment.
    We do not believe an approval, as proposed, will interfere with CAA
requirements for BART or for preventing interference with other states'
programs to protect visibility because our proposal is supported by an
evaluation that those CAA requirements are met. An approval will not
result in any substantive changes to the BART requirements or other CAA
requirements, and the AEP/PSO units will continue to be subject to the
CAA requirements for BART. The SIP replaces a federal determination
that was based on different underlying facts. Because of this, the
submitted SIP cannot be said to be less stringent than the
determination in the FIP. We also believe that approval of the
submitted SIP revision will not interfere with attainment and
maintenance of the NAAQS within the state of Oklahoma. The submitted
SIP revision, if approved, will reduce emissions from the current
levels allowed to impact local air quality. The area where the
Northeastern facility is located has not been designated nonattainment
for any NAAQS pollutants nor have any nearby areas. The revision being
approved here will result in reductions in NOx and SO2 over
existing levels, and therefore, we do not deem this to be an instance
where a full attainment or maintenance demonstration is needed to
bolster our determination that approval of the submitted SIP revision
would not interfere with attainment and maintenance of the NAAQS. The
FIP, were it to remain in place, would assuredly also preserve, if not
improve upon, status quo air quality. However, the requirement for BART
takes its form in future implemented emission reductions. We are not
aware of any basis for concluding or demonstrating that the regional
haze SIP revisions, when implemented, would interfere with the
maintenance of the NAAQS in Oklahoma.

VII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
proposed

action merely approves state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Order
12866 (58 FR 51735, October 4, 1993);
     does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act; and
     does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this rule does not have tribal implications as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000)
because the SIP is not approved to apply in Indian country located in
the state, and EPA notes that it will not impose substantial direct
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental
relations, Nitrogen dioxide, Particulate matter, Regional haze,
Reporting and recordkeeping requirements, Sulfur dioxide, Visibility,
and Volatile organic compounds.

    Dated: August 12, 2013.
Samuel Coleman,
P.E., Acting Regional Administrator, Region 6.

    Title 40, chapter I, of the Code of Federal Regulations is proposed
to be amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

0
2. Section 52.1923 is amended by:
0
a. Revising the section heading; and
0
b. Revising paragraphs (a), (c), and (e)(1).
    The revised text read as follows:

Sec.  52.1923  Best Available Retrofit Requirements (BART) for
SO2 and Interstate pollutant transport provisions; What are
the FIP requirements for Units 4 and 5 of the Oklahoma Gas and Electric
Muskogee plant; and Units 1 and 2 of the Oklahoma Gas and Electric
Sooner plant affecting visibility?

    (a) Applicability. The provisions of this section shall apply to
each owner or operator, or successive owners or operators, of the coal
burning equipment designated as: Units 4 or 5 of the Oklahoma Gas and
Electric Muskogee plant; and Units 1 or 2 of the Oklahoma Gas and
Electric Sooner plant.
* * * * *
    (c) Definitions. All terms used in this part but not defined herein
shall have the meaning given them in the CAA and in parts 51 and 60 of
this chapter. For the purposes of this section:
    24-hour period means the period of time between 12:01 a.m. and 12
midnight.
    Air pollution control equipment includes selective catalytic
control units, baghouses, particulate or gaseous scrubbers, and any
other apparatus utilized to control emissions of regulated air
contaminants that would be emitted to the atmosphere.
    Boiler-operating-day means any 24- hour period between 12:00
midnight and the following midnight during which any fuel is combusted
at any time at the steam generating unit.
    Daily average means the arithmetic average of the hourly values
measured in a 24-hour period.
    Heat input means heat derived from combustion of fuel in a unit and
does not include the heat input from preheated combustion air,
recirculated flue gases, or exhaust gases from other sources. Heat
input shall be calculated in accordance with 40 CFR part 75.
    Owner or Operator means any person who owns, leases, operates,
controls, or supervises any of the coal burning equipment designated
as:

Unit 4 of the Oklahoma Gas and Electric Muskogee plant; or
Unit 5 of the Oklahoma Gas and Electric Muskogee plant; or
Unit 1 of the Oklahoma Gas and Electric Sooner plant; or
Unit 2 of the Oklahoma Gas and Electric Sooner plant.

    Regional Administrator means the Regional Administrator of EPA
Region 6 or his/her authorized representative.
    Unit means one of the coal fired boilers covered under Paragraph
(a), above.
* * * * *
    (e) * * *
    (1) No later than the compliance date of this regulation, the owner
or operator shall install, calibrate, maintain and operate Continuous
Emissions Monitoring Systems (CEMS) for SO2 on Units 4 and 5
of the Oklahoma Gas and Electric Muskogee plant; and Units 1 and 2 of
the Oklahoma Gas and Electric Sooner plant in accordance with 40 CFR
60.8 and 60.13(e), (f), and (h), and Appendix B of Part 60. The owner
or operator shall comply with the quality assurance procedures for CEMS
found in 40 CFR part 75. Compliance with the emission limits for
SO2 shall be determined by using data from a CEMS.
* * * * *
[FR Doc. 2013-20317 Filed 8-20-13; 8:45 am]
BILLING CODE 6560-50-P