[Federal Register Volume 77, Number 48 (Monday, March 12, 2012)]
[Rules and Regulations]
[Pages 14604-14677]
[FR Doc No: 2012-4493]

Vol. 77

Monday,

No. 48

March 12, 2012

Part II

Environmental Protection Agency

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40 CFR Part 52

Approval and Promulgation of Implementation Plans; Arkansas; Regional
Haze State Implementation Plan; Interstate Transport State
Implementation Plan To Address Pollution Affecting Visibility and
Regional Haze; Final Rule

Federal Register / Vol. 77 , No. 48 / Monday, March 12, 2012 / Rules
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2008-0727; FRL-9637-4]

Approval and Promulgation of Implementation Plans; Arkansas;
Regional Haze State Implementation Plan; Interstate Transport State
Implementation Plan To Address Pollution Affecting Visibility and
Regional Haze

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The EPA is partially approving and partially disapproving a
revision to the Arkansas State Implementation Plan (SIP) intended to
address the regional haze (RH) requirements of the Clean Air Act (CAA
or Act). In addition, EPA is partially approving and partially
disapproving the portion of the Arkansas Interstate Transport SIP
submittal that addresses the visibility requirement of section
110(a)(2)(D)(i)(II) for the 1997 8-hour ozone and 1997 fine particulate
matter (PM2.5) national ambient air quality standards
(NAAQS) that the Arkansas SIP contain adequate provisions to prohibit
emissions from interfering with measures required in another state to
protect visibility. EPA is approving certain core elements of the RH
SIP including: identification of affected Class I areas; determination
of baseline and natural visibility conditions; determination of Uniform
Rate of Progress (URP); reasonable progress goal (RPG) consultation and
long term strategy (LTS) consultation; coordination of RH and
reasonably attributable visibility impairment (RAVI); regional haze
monitoring strategy and other SIP requirements under 40 CFR
51.308(d)(4); commitment to submit periodic regional haze SIP revisions
and periodic progress reports describing progress towards the RPGs;
commitment to make a determination of the adequacy of the existing SIP
at the time a progress report is submitted; and consultation and
coordination with Federal land managers (FLMs). EPA is partially
approving and partially disapproving portions of other core elements of
the SIP including: identification of best available retrofit technology
(BART) eligible sources and subject to BART sources; requirements for
BART; Chapter 15 of the Air Pollution Control and Ecology Commission
(APCEC) Regulation No. 19, also known as the State's RH Rule; and the
LTS. EPA is disapproving Arkansas's reasonable progress goals (RPGs)
required under 40 CFR 51.308(d)(1). This action is being taken under
section 110 and part C of the CAA.

DATES: This final rule is effective on April 11, 2012.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-R06-OAR-2008-0727. All documents in the docket are listed in
the Federal e-Rulemaking portal index at http://www.regulations.gov and
are available either electronically at http://www.regulations.gov or in
hard copy at EPA Region 6, 1445 Ross Ave., Dallas, TX 75202-2733. To
inspect the hard copy materials, please schedule an appointment during
normal business hours with the contact listed in the FOR FURTHER
INFORMATION CONTACT section. A reasonable fee may be charged for
copies.

FOR FURTHER INFORMATION CONTACT: Ms. Dayana Medina, Air Planning
Section (6PD-L), Environmental Protection Agency, Region 6, 1445 Ross
Avenue, Suite 700, Dallas, Texas 75202-2733, telephone<PHONE_NUMBER>;
fax number<PHONE_NUMBER>; email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' ``our,'' or ``the Agency'' is used, we mean the EPA.

Overview

    The CAA requires that states develop and implement SIPs to reduce
the pollution that causes visibility impairment over a wide geographic
area, known as Regional Haze (RH). CAA sections 110(a) and 169A.
Arkansas submitted a RH plan to us on September 23, 2008, and August 3,
2010, and submitted supplemental information on September 27, 2011. On
October 17, 2011, we proposed to partially approve and partially
disapprove certain elements of Arkansas's SIP.\1\ Today, we are taking
final action by partially approving and partially disapproving the
elements of Arkansas's RH SIP addressed in our proposed rule.
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    \1\ 76 FR 64186.
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    In addition to the RH requirements, CAA section 110(a)(2)(D)(i)(II)
requires that the Arkansas SIP ensure that emissions from sources
within Arkansas do not interfere with the SIP of any other state under
part C of the CAA to protect visibility. This requirement is commonly
referred to as the visibility prong of ``interstate transport,'' which
is also called the ``good neighbor'' provision of the CAA. Arkansas
submitted a SIP to meet the requirements of interstate transport for
the 1997 8-hour ozone and PM2.5 NAAQS on April 2, 2008, and
supplemented it on September 27, 2011. On October 17, 2011, we proposed
to partially approve and partially disapprove this submission as it
relied upon the State's RH Rule that we were proposing to partially
approve and partially disapprove. Id. Because the Interstate Transport
SIP is conditioned upon the BART determinations in the RH SIP, we are
also taking final action by partially approving and partially
disapproving elements of Arkansas's Interstate Transport SIP addressed
in our proposed rule.
    Arkansas submitted Chapter 15 of APCEC Regulation No. 19, its State
RH Rule that addresses Arkansas's RH program, to address the
requirements in both its RH SIP and its Interstate Transport SIP. In
both the RH SIP and the Interstate Transport SIP, Arkansas adopted BART
emission limits for certain sources to meet the requirements of both
SIPs as stated in the State RH Rule. Based upon public comment, we are
disapproving the portion of the BART compliance provision found in the
State's RH Rule, Chapter 15 of APCEC Regulation No. 19, at Reg. 19.1504
(B), which requires each source subject to BART to install and operate
BART no later than six years after the effective date of Arkansas's RH
Rule for both the RH SIP and the Interstate Transport SIP. Because of
this disapproval, compliance with Arkansas's BART emission limitations
is within five years of approval of Arkansas RH SIP by EPA.
    For a RH SIP, 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. Second, states determine whether such sources
``emit 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''). Third, for
each source subject to BART, states then identify the appropriate type
and the level of control for reducing emissions by conducting a five-
step analysis: 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.

    We agree with Arkansas's identification of sources that are BART
eligible, with the exception of the 6A Boiler at the Georgia-Pacific
Crossett Mill, which we find to be BART eligible. We also agree with
Arkansas's identification of subject to BART sources, with the
exception of the 6A and 9A Boilers at the Georgia-Pacific Crossett
Mill, which we find to be subject to BART. In addition, we are
approving a number of BART determinations from Arkansas's RH SIP. We
are not able to approve the following BART determinations made by
Arkansas: the sulfur dioxide (SO2), nitrogen dioxide
(NOX), and particulate matter (PM) BART determinations for
the Arkansas Electric Cooperative Corporation (AECC) Bailey Plant Unit
1 and the AECC McClellan Plant Unit 1; the SO2 and
NOX BART determinations for the American Electric Power
(AEP) Flint Creek Plant Boiler No. 1; the NOX BART
determination for the natural gas firing scenario and the
SO2, NOX, and PM BART determinations for the fuel
oil firing scenario for the Entergy Lake Catherine Plant Unit 4; the
SO2 and NOX BART determinations for both the
bituminous and sub-bituminous coal firing scenarios for the Entergy
White Bluff Plant Units 1 and 2; the BART determination for the Entergy
White Bluff Plant Auxiliary Boiler; the SO2 and
NOX BART determinations for the Domtar Ashdown Mill Power
Boiler No. 1; and the SO2, NOX and PM BART
determinations for the Domtar Ashdown Mill Power Boiler No. 2. In
reviewing the State's BART determinations for these pollutants and
units, we found that the State did not satisfy all the regulatory and
statutory requirements in making these BART determinations. We have
therefore determined it is appropriate to finalize our proposed
disapproval of the State's BART determinations for these units, because
we conclude that the flaws and omissions in the State's BART analyses
were significant, and that the State therefore lacked adequate record
support and a reasoned basis for its analyses, as required by the RH
Rule (RHR). As we previously noted, Arkansas submitted Chapter 15 of
APCEC Regulation No. 19, also known as the State's RH Rule, as a SIP
revision to address both RH and the visibility transport requirements.
With respect to RH, we are partially approving and partially
disapproving Chapter 15 of APCEC Regulation No. 19, such that our
disapproval is of those portions of the State's RH Rule that correspond
to portions of the Arkansas RH SIP we are disapproving. In particular,
we note that based upon public comment, we also are disapproving the
portion of the BART compliance provision found in Chapter 15 of APCEC
Regulation No. 19, at Reg. 19.1504(B), which requires each source
subject to BART to install and operate BART requirements no later than
six years after the effective date of the State's regulation. We are
approving the portion of the BART compliance provision that requires
each Arkansas subject to BART source to install and operate BART as
expeditiously as practicable, but in no event later than five years
after EPA approval of the Arkansas RH SIP, for those sources' BART
determinations we are approving. We find that this is consistent with
the requirements under 40 CFR 51.308(e)(iv). Arkansas's inclusion of
the compliance provision that would require Arkansas subject to BART
sources to install and operate BART no later than six years after the
effective date of the State's regulation (if such date takes place
before five years from EPA approval of the Arkansas RH SIP) is not a
required element of the RH SIPs to be developed and submitted by states
pursuant to section 169 of the CAA. We are also partially approving and
partially disapproving the State's submitted LTS because it relies on
portions of the RH SIP we are disapproving, including some of
Arkansas's BART emission limits. We are disapproving the State's RPGs
under 40 CFR 51.308(d)(1) because Arkansas did not consider the four
factors that states are required to consider in establishing RPGs under
the CAA and 40 CFR 51.308(d)(1)(A).
    We are approving the remaining sections of the RH SIP submission.
This includes certain core elements of the SIP, including Arkansas's
(1) Identification of affected Class I areas; (2) determination of
baseline and natural visibility conditions; (3) determination of the
URP; (4) RPG consultation and LTS consultation; (5) coordination of
regional haze and reasonably attributable visibility impairment; (6)
monitoring strategy and other implementation requirements; (7)
commitment to submit periodic RH SIP revisions and periodic progress
reports describing progress towards the RPGs; (8) commitment to make a
determination of the adequacy of the existing SIP at the time a
progress report is submitted; (9) coordination with states and FLMs;
and (10) the following BART determinations from Arkansas's RH SIP:
     The PM BART determination for the AEP Flint Creek Plant
Boiler No. 1.
     The SO2 and PM BART determinations for the
natural gas firing scenario for the Entergy Lake Catherine Plant Unit
4.
     The PM BART determinations for both the bituminous and
sub-bituminous coal firing scenarios for the Entergy White Bluff Plant
Units 1 and 2.
     The PM BART determination for the Domtar Ashdown Mill
Power Boiler No. 1.
    Arkansas stated in its April 2, 2008 submittal that it is relying
on Chapter 15 of APCEC Regulation No. 19, also known as the State's RH
Rule, to satisfy the requirements of section 110(a)(2)(D)(i)(II) that
emissions from Arkansas sources not interfere with measures required in
the SIP of any other state under part C of the CAA to protect
visibility. The Arkansas Department of Environmental Quality (ADEQ)
also stated in its April 2, 2008, submittal that it is not possible to
assess whether there is any interference with the measures in the
applicable SIP for another state designed to protect visibility for the
8-hour ozone and PM2.5 NAAQS until ADEQ submits and EPA
approves Arkansas's RH SIP. We proposed to partially approve and
partially disapprove this submission as it relied upon the State's RH
Rule that we were proposing to partially approve and partially
disapprove. In developing their RH SIP and RPGs, Arkansas and
potentially impacted States collaborated through the Central Regional
Air Planning (CENRAP) association. Each state developed its RH Plans
and RPGs based on the CENRAP modeling. The CENRAP modeling was based in
part on the emissions reductions each state intended to achieve by
2018. Some of the emissions reductions included in the CENRAP's
modeling and thus relied upon by other states, were from BART controls
on Arkansas subject to BART sources. Compliance with these BART
requirements will ensure that Arkansas obtains its share of the
emission reductions relied upon by other states to meet the RPGs for
their Class I areas. As already previously discussed in this final
rulemaking, Arkansas submitted Chapter 15 of APCEC Regulation No. 19,
also known as the State's RH Rule, as a SIP revision to address both RH
and the visibility transport requirements. With respect to the
visibility interstate transport SIP, we are partially approving and
partially disapproving the submitted Chapter 15 of APCEC Regulation No.
19, such that our disapproval is of those portions that correspond to
the submitted BART determinations we are disapproving. In response to
public comment, we note that we also are disapproving the portion of
the BART compliance

provision found in the APCEC Regulation No. 19, at Reg. 19.1504(B),
which requires each source subject to BART to install and operate BART
no later than six years after the effective date of the State's
regulation. Since compliance of Arkansas's subject to BART sources with
BART requirements now is solely dependent upon our approval of the RH
SIP, and since we are disapproving the portion of the RH SIP which
includes some of Arkansas's BART determinations, a portion of the
emission reductions committed to by Arkansas and relied upon by other
states will not be realized. Consequently, Arkansas's emissions will
interfere with other states' SIPs to protect visibility. Therefore, we
are partially approving and partially disapproving the portion of the
Arkansas Interstate Transport SIP submittal that addresses the
visibility requirement of section 110(a)(2)(D)(i)(II) that emissions
from Arkansas sources not interfere with measures required in the SIP
of any other state under part C of the CAA to protect visibility.
    Under the CAA,\2\ we must, within 24 months following a final
disapproval, either approve a SIP or promulgate a Federal
Implementation Plan (FIP). We will of course consider, and would
prefer, approving a SIP if the state submits a revised plan that we can
approve before the expiration of the mandatory FIP clock for the
portions of the SIP we are disapproving in this rulemaking action.
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    \2\ CAA section 110(c)(1).
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    We originally provided a 30 day public comment period for this
action, which we extended after receiving several requests for an
extension on the comment period. We held a 66 day public comment period
for this action. Many public commenters disagreed with several aspects
of our proposal, expressing the belief that we should approve either
more portions of the Arkansas RH SIP or the SIP in its entirety. We
also received public comments agreeing with several aspects of our
proposal, expressing the belief that we should disapprove either more
portions of the Arkansas RH SIP or the SIP in its entirety. All public
comments and our responses are discussed in more detail in section III
of this final rulemaking action.
    This action is being taken under section 110 and part C of the CAA.

Table of Contents

I. Summary of Our Proposal
    A. Regional Haze
    B. Interstate Transport of Pollutants and Visibility Protection
II. Final Decision
    A. Regional Haze
    B. Interstate Transport of Pollutants and Visibility Protection
III. Public Comments Received and Our Responses
    A. Comments on Presumptive Emission Limits
    B. Comments on Reasonable Progress Goals and Long Term Strategy
    C. Comments on BART
    1. Evaluation of the Most Stringent Level of Control in the BART
Analysis
    2. Evaluation of Post-Combustion Controls in the BART Analysis
    3. Comments on the State's PM BART Emission Limits We Proposed
to Approve
    4. Comments on the Capacity Factor Used in the State's BART
Analyses for Entergy Lake Catherine and White Bluff
    5. Comments on the State's Cost Evaluations
    6. Comments on the August 2008 Revised BART Analysis for White
Bluff
    7. Other Comments Related to BART
    D. Comments on the Arkansas Pollution Control and Ecology
Commission Variance for Subject to BART Sources
    E. Comments on BART and the Forthcoming MACT Requirements
    F. Comments on Modeling
    G. Comments on Legal Issues
    1. Comments on Regional Haze
    2. Comments on Interstate Transport and Visibility
    H. Other Comments
    I. Comments Requesting an Extension to the Public Comment Period
IV. Statutory and Executive Order Reviews

I. Summary of Our Proposal

    On October 17, 2011, we published the proposal on which we are now
taking final action.\3\ We proposed to partially approve and partially
disapprove Arkansas's RH SIP revision submitted on September 23, 2008,
August 3, 2010, and supplemented on September 27, 2011. We also
proposed to partially approve and partially disapprove a portion of a
SIP revision we received from the State of Arkansas on April 2, 2008,
as supplemented on September 27, 2011, for the purpose of addressing
the ``good neighbor'' provisions of the CAA section 110(a)(2)(D)(i)(II)
with respect to visibility for the 1997 8-hour ozone NAAQS and the
PM2.5 NAAQS.
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    \3\ 76 FR 64186.
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A. Regional Haze

    We proposed to approve the State's identification of BART-eligible
sources, with the exception of the 6A Boiler at the Georgia-Pacific
Crossett Mill, which we find to be BART-eligible. We proposed to
approve the State's identification of subject to BART sources, with the
exception of the 6A and 9A Boilers at the Georgia-Pacific Crossett
Mill, which we find to be subject to BART. We also proposed to approve
certain core elements of the SIP, including Arkansas's (1)
identification of affected Class I areas; (2) determination of baseline
and natural visibility conditions; (3) determination of the URP; (4)
RPG consultation and LTS consultation; (5) coordination of regional
haze and reasonably attributable visibility impairment; (6) monitoring
strategy and other implementation requirements; (7) commitment to
submit periodic RH SIP revisions and periodic progress reports
describing progress towards the RPGs; (8) commitment to make a
determination of the adequacy of the existing SIP at the time a
progress report is submitted; (9) coordination with states and FLMs;
and (10) the following BART determinations from Arkansas's RH SIP: the
PM BART determination for the AEP Flint Creek Plant Boiler No. 1; the
SO2 and PM BART determinations for the natural gas firing
scenario for the Entergy Lake Catherine Plant Unit 4; the PM BART
determinations for both the bituminous and sub-bituminous coal firing
scenarios for the Entergy White Bluff Plant Units 1 and 2; and PM BART
determination for the Domtar Ashdown Mill Power Boiler No. 1.
    We proposed to disapprove Arkansas's SO2,
NOX, and PM BART determinations for the AECC Bailey Plant
Unit 1 and the AECC McClellan Plant Unit 1; the SO2 and
NOX BART determinations for the AEP Flint Creek Plant Boiler
No. 1; the NOX BART determination for the natural gas firing
scenario and the SO2, NOX, and PM BART
determinations for the fuel oil firing scenario for the Entergy Lake
Catherine Plant Unit 4; the SO2 and NOX BART
determinations for both the bituminous and sub-bituminous coal firing
scenarios for the Entergy White Bluff Plant Units 1 and 2; the BART
determination for the Entergy White Bluff Plant Auxiliary Boiler; the
SO2 and NOX BART determinations for the Domtar
Ashdown Mill Power Boiler No. 1; and the SO2, NOX
and PM BART determinations for the Domtar Ashdown Mill Power Boiler No.
2 because they do not comply with our regulations under 40 CFR
51.308(e). We also proposed to partially approve and partially
disapprove the Arkansas RH Rule, Chapter 15 of APCEC Regulation No. 19,
such that our proposed disapproval was of those portions of the State's
RH Rule that correspond to portions of the Arkansas RH SIP we were
proposing to disapprove. We also proposed to partially approve and
partially disapprove the LTS under 40 CFR

51.308(d)(3) because Arkansas has not shown that the strategy is
adequate to achieve the RPGs set by Arkansas and by other nearby
states.
    We proposed to disapprove the State's RPGs under 40 CFR
51.308(d)(1) because Arkansas did not consider the four factors states
are required to consider in establishing RPGs under the CAA and 40 CFR
51.308(d)(1)(A).

B. Interstate Transport of Pollutants and Visibility Protection

    We proposed to partially approve and partially disapprove a portion
of a SIP revision we received from the State of Arkansas on April 2,
2008, as supplemented on September 27, 2011, for the purpose of
addressing the ``good neighbor'' provisions of the CAA section
110(a)(2)(D)(i) with respect to visibility for the 1997 8-hour ozone
NAAQS and the PM2.5 NAAQS. This SIP revision addressed the
requirement of section 110(a)(2)(D)(i)(II) that emissions from Arkansas
sources do not interfere with measures required in the SIP of any other
state under part C of the CAA to protect visibility. ADEQ participated
in the CENRAP visibility modeling development that assumed certain
SO2, NOX, and PM reductions from Arkansas's BART
sources. Compliance with these BART requirements will ensure that
Arkansas obtains its share of the emission reductions relied upon by
other states to meet the RPGs for their Class I areas. Since compliance
of Arkansas's subject to BART sources with BART requirements is
dependent upon our approval of the RH SIP, and since we proposed to
disapprove the portion of the RH SIP which includes some of Arkansas's
BART determinations, a portion of the emission reductions committed to
by Arkansas and relied upon by other states will not be realized and,
as a consequence, Arkansas's emissions will interfere with other
states' SIPs to protect visibility.

II. Final Decision

A. Regional Haze

    With one exception, we are finalizing our action as proposed. As
discussed below, based upon public comment, we are adjusting our action
on the Arkansas RH Rule. We are partially approving and partially
disapproving the Arkansas RH SIP revision submitted on September 23,
2008, August 3, 2010, and supplemented on September 27, 2011. We are
approving Arkansas's identification of sources that are BART eligible,
with the exception of the 6A Boiler at the Georgia-Pacific Crossett
Mill, which we find to be BART-eligible. We are also approving
Arkansas's identification of subject to BART sources, with the
exception of the 6A and 9A Boilers at the Georgia-Pacific Crossett
Mill, which we find to be subject to BART.
    We are disapproving Arkansas's SO2, NOX, and
PM BART determinations for the AECC Bailey Plant Unit 1 and the AECC
McClellan Plant Unit 1; the SO2 and NOX BART
determinations for the AEP Flint Creek Plant Boiler No. 1; the
NOX BART determination for the natural gas firing scenario
and the SO2, NOX, and PM BART determinations for
the fuel oil firing scenario for the Entergy Lake Catherine Plant Unit
4; the SO2 and NOX BART determinations for both
the bituminous and sub-bituminous coal firing scenarios for the Entergy
White Bluff Plant Units 1 and 2; the BART determination for the Entergy
White Bluff Plant Auxiliary Boiler; the SO2 and
NOX BART determinations for the Domtar Ashdown Mill Power
Boiler No. 1; and the SO2, NOX and PM BART
determinations for the Domtar Ashdown Mill Power Boiler No. 2. With
respect to RH, we are partially approving and partially disapproving
the Arkansas RH Rule, Chapter 15 of APCEC Regulation No. 19, such that
our disapproval is of those portions of the State's RH Rule that
correspond to portions of the Arkansas RH SIP we are disapproving and
our approval is of the remaining portions. We do note that in response
to comments received, we are making one change to the portions of the
Arkansas RH Rule we are approving from what we proposed to approve in
our October 17, 2011, proposed rulemaking. Specifically, in our
proposed rulemaking, we proposed to approve Reg. 19.1504(B), which
requires Arkansas's subject to BART sources to ``install and operate
BART as expeditiously as practicable, but in no event later than 6
years after the effective date of [the State RH Rule] or 5 years after
EPA approval of the Arkansas Regional Haze State Implementation Plan,
whichever comes first.'' As discussed in more detail in our response to
comments, because the State revised its rule to delete the provision
that would require Arkansas's subject to BART sources to comply with
BART within 6 years of the effective date of the State RH Rule, we are
disapproving this portion of the BART compliance provision found in
Chapter 15 of APCEC Regulation No. 19. We are partially approving and
partially disapproving the portion of the BART compliance provision
that requires each Arkansas subject to BART source to install and
operate BART as expeditiously as practicable, but in no event later
than five years after EPA approval of the Arkansas RH SIP. The
disapproval is of those portions of the State's RH Rule that correspond
to portions of the Arkansas RH SIP we are disapproving. We find that
this is consistent with the requirements under 40 CFR 51.308(e)(iv). We
are partially approving and partially disapproving the LTS under 40 CFR
51.308(d)(3). We are disapproving the State's RPGs under 40 CFR
51.308(d)(1).
    We are approving the remaining sections of the RH SIP submission.
This includes certain core elements of the SIP, including Arkansas's
(1) identification of affected Class I areas; (2) determination of
baseline and natural visibility conditions; (3) determination of the
URP; (4) RPG consultation and LTS consultation; (5) coordination of
regional haze and reasonably attributable visibility impairment; (6)
monitoring strategy and other implementation requirements; (7)
commitment to submit periodic RH SIP revisions and periodic progress
reports describing progress towards the RPGs; (8) commitment to make a
determination of the adequacy of the existing SIP at the time a
progress report is submitted; (9) coordination with states and FLMs;
and (10) the following BART determinations from Arkansas's RH SIP:
     The PM BART determination for the AEP Flint Creek Plant
Boiler No. 1.
     The SO2 and PM BART determinations for the
natural gas firing scenario for the Entergy Lake Catherine Plant Unit
4.
     The PM BART determinations for both the bituminous and
sub-bituminous coal firing scenarios for the Entergy White Bluff Plant
Units 1 and 2.
     The PM BART determination for the Domtar Ashdown Mill
Power Boiler No. 1.

B. Interstate Transport of Pollutants and Visibility Protection

    We are partially approving and partially disapproving a portion of
a SIP revision we received from the State of Arkansas on April 2, 2008,
as supplemented on September 27, 2011, for the purpose of addressing
the ``good neighbor'' provisions of the CAA section 110(a)(2)(D)(i)
with respect to visibility for the 1997 8-hour ozone NAAQS and the
PM2.5 NAAQS. Because Arkansas relied on Chapter 15 of APCEC
Regulation No. 19, to satisfy the requirements of section
110(a)(2)(D)(i)(II) that emissions from Arkansas sources not interfere
with

measures required in the SIP of any other state under part C of the CAA
to protect visibility, we are partially approving and partially
disapproving the submitted Chapter 15 of APCEC Regulation No. 19, such
that our disapproval is of those portions that correspond to the
submitted BART determinations we are disapproving. In response to
public comment, we note that we also are disapproving the portion of
the BART compliance provision found in the APCEC Regulation No. 19, at
Reg. 19.1504(B), which requires each source subject to BART to install
and operate BART no later than six years after the effective date of
the State's regulation. Since compliance of Arkansas's subject to BART
sources with BART requirements now is solely dependent upon our
approval of the RH SIP, and since we are disapproving the portion of
the RH SIP which includes some of Arkansas's BART determinations, a
portion of the emission reductions committed to by Arkansas and relied
upon by other states will not be realized and, as a consequence,
Arkansas's emissions will interfere with other states' SIPs to protect
visibility. Therefore, we are partially approving and partially
disapproving the portion of the Arkansas Interstate Transport SIP
submittal that addresses the visibility requirement of section
110(a)(2)(D)(i)(II) that emissions from Arkansas sources not interfere
with measures required in the SIP of any other state under part C of
the CAA to protect visibility.

III. Public Comments Received and Our Responses

    During the public notice and comment period, we received 13 comment
letters both supporting and opposing our proposal. We received comments
from the ADEQ, the Utah Department of Environmental Quality (UDEQ), the
National Park Service, the Sierra Club, Entergy Arkansas Inc., the
American Electric Power/Southwestern Electric Power Company (AEP-
SWEPCO), the Arkansas Electric Cooperative Corporation, Domtar
Industries Inc., Nucor Steel-Arkansas, the Competitive Enterprise
Institute, the Utility Air Regulatory Group, PacifiCorp Energy, and the
Energy and Environmental Alliance of Arkansas. The comments we received
opposing our proposal contended that we had either overstepped our
bounds in proposing a partial disapproval or that we had not gone far
enough in our action and should fully disapprove Arkansas's RH SIP.
Many of the comments received are similar in nature and are grouped
together accordingly. Thus, many of the comments you will read are
representative of more than one comment letter. The comments are
summarized and addressed below. The full text received from these
commenters is included in the docket associated with this action.

A. Comments on Presumptive Emission Limits

    Comment: The SO2 and NOX BART determinations
for the AEP Flint Creek Boiler No. 1 and Entergy White Bluff Plant
Units 1 and 2 meet the presumptive BART limits established in 40 CFR
part 51, appendix Y (BART Guidelines). In the Arkansas RH proposal, EPA
did not justify its decision that the presumptive BART limits are
unacceptable. EPA is insisting on a five factor analysis even when a
source can meet the presumptive limits. EPA's current interpretation of
the presumptive BART limits makes the presumptive BART limits
meaningless, contrary to the requirements of the CAA and the clear
intent of the BART Rule. The CAA singles out electric generating units
(EGUs) located at 750 megawatt (MW) power plants for specific BART
controls (42 U.S.C. 7491(b)(2)), and EPA adopted the presumptive BART
limits to establish the specific control levels required for these
EGUs. Since EPA went through extensive analysis to establish
presumptive BART limits, the only rational explanation is that EPA
intended for those limits to be meaningful. EPA is rationalizing its
decision on the Arkansas RH SIP as if the presumptive BART limits were
no longer a binding regulation, and there is concern that EPA is
attempting to establish new, more stringent presumptive BART limits
through case-by-case disapprovals of state BART determinations. Unless
and until EPA goes through notice and comment rulemaking to remove the
presumptive emission limits and establish other requirements consistent
with the CAA, the presumptive BART limits in the promulgated BART Rule
continue to establish the requirement that states must meet in their
regional haze SIPs for large coal-fired EGUs and EPA must approve a
state's BART determination if it meets the presumptive regulatory
limits.
    Response: Our application of the presumptive BART limits in our
proposed rulemaking on the Arkansas RH SIP gives proper treatment of
presumptive BART limits and is consistent with the requirements of the
CAA and the intent of the BART Rule.
    We note that the states generally have broad authority to decide
appropriate BART controls. However, the CAA gives EPA a more active
role in establishing BART emission limits for large power plants.\4\
The CAA states the following regarding emission limits for fossil-fuel
fired generating power plants having a total generating capacity in
excess of 750 MW:
---------------------------------------------------------------------------

    \4\ 69 FR 39129 and CAA section 169(a)(4).
---------------------------------------------------------------------------

    ``In the case of a fossil-fuel fired generating power plant having
a total generating capacity in excess of 750 megawatts, the emissions
limitations required under this paragraph shall be determined pursuant
to guidelines, promulgated by the Administrator under paragraph (1).''
\5\
---------------------------------------------------------------------------

    \5\ 42 U.S.C. 7491(b).
---------------------------------------------------------------------------

    EPA disagrees that the CAA mandates specific control levels (i.e.
presumptive emission limits) for power plants with a total generating
capacity of 750 MW or greater. Rather, the CAA directed EPA to develop
guidelines for States to establish BART emission limits, and required
that power plants having a total generating capacity in excess of 750
MW follow the guidelines when establishing BART emission limits. In
response, in 2005 EPA promulgated the BART Guidelines, which provide a
detailed description of how a State must approach the BART
determination process for certain large EGUs, and required that the
determination of fossil-fuel fired power plants having a total
generating capacity greater than 750 MW must be made pursuant to the
BART Guidelines.\6\ As such, the plain reading of the CAA language
makes it clear the intent was to make the BART Guidelines mandatory for
EGUs larger than 750 MW, as opposed to presumptive limits. Therefore,
EPA's proposed rulemaking on the Arkansas RH SIP is not contrary to the
requirements of the CAA.
---------------------------------------------------------------------------

    \6\ 40 CFR 51.308(e)(1)(ii)(B) and Appendix Y to Part 51.
---------------------------------------------------------------------------

    The EPA went through extensive analysis to establish presumptive
BART emission limits, and intended these limits to be meaningful. As
stated in our proposed rulemaking on the Arkansas RH SIP, the purpose
of the presumptive limits in the BART Guidelines was to identify
controls that the Agency considered to be generally cost-effective
across all affected units. Because EPA's extensive analysis found that
these controls are generally cost-effective across all affected units
and were anticipated to result in a substantial degree of visibility
improvement, EPA concluded that such units should at least meet the
presumptive limits. However, EPA's BART Rule does not state that the
presumptive limits will represent the ``best available retrofit

controls'' for all EGUs at these larger power plants. Instead, EPA's
BART Rule and the BART Guidelines make clear that in developing the
presumptive emission limits, EPA made many design and technological
assumptions, and that the presumptive limits may not be BART in every
case. As such, the presumption in the BART Rule is not that the
presumptive limits will be BART in every case. Rather, the presumption
in the BART Rule is more accurately interpreted to be that the controls
reflected by the presumptive limits are cost-effective and will result
in considerable visibility improvement. EPA's intent was for these
generally cost-effective controls to be used in the State's BART
analysis considering the five factors specified in CAA section
169A(g)(2), and considering the level of control that is currently
achievable at the time that the BART analysis is being conducted.
    We note the RHR states:

    ``States, as a general matter, must require owners and operators
of greater than 750 MW power plants to meet these BART emission
limits. We are establishing these requirements based on the
consideration of certain factors discussed below. Although we
believe that these requirements are extremely likely to be
appropriate for all greater than 750 MW power plants subject to
BART, a State may establish different requirements if the State can
demonstrate that an alternative determination is justified based on
a consideration of the five statutory factors.'' \7\
---------------------------------------------------------------------------

    \7\ 70 FR 39131.

---------------------------------------------------------------------------
    The RHR also states:

    ``If, upon examination of an individual EGU, a State determines
that a different emission limit is appropriate based upon its
analysis of the five factors, then the State may apply a more or
less stringent limit.'' \8\
---------------------------------------------------------------------------

    \8\ 70 FR 39132.

    Therefore, the presumptive emission limits in the BART Guidelines
are rebuttable.\9\ The presumptive emission limits apply to power
plants with a total generating capacity of 750 MW or greater insofar as
these sources are required to adopt emission limits at least as
stringent as the presumptive limits, unless after considering the five
statutory factors, the State determines that the presumptive emission
limits are not appropriate. Moreover, the RHR and BART Guidelines do
not exempt states from a five factor BART analysis, and that BART
analysis may result in a determination of BART emission limits that are
more or less stringent than the presumptive emission limits for subject
to BART sources. The RHR states:
---------------------------------------------------------------------------

    \9\ 71 FR 60619.

    ``For each source subject to BART, 40 CFR 51.308(e)(1)(ii)(A)
requires that States identify the level of control representing BART
after considering the factors set out in CAA section 169A(g), as
follows:
States must identify the best system of continuous emission control
technology for each source subject to BART taking into account 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 visibility improvement that may be
expected from available control technology.'' \10\
---------------------------------------------------------------------------

    \10\ 70 FR 39158.

    As previously stated, the presumptive emission limits apply to
power plants with a total generating capacity of 750 MW or greater
insofar as these sources are required to adopt emission limits at least
as stringent as the presumptive limits, unless after considering the
five statutory factors, the State determines that a more or less
stringent emission limit is appropriate. Further, EPA is not attempting
to establish new, more stringent presumptive BART limits. As a matter
of fact, EPA's proposed rulemaking did not propose to establish
particular BART emission limits on any of Arkansas's subject to BART
sources. Instead, EPA's proposed rulemaking proposed to disapprove the
State's BART limits where the State adopted the NOX and
SO2 presumptive emission limits without conducting a proper
five factor BART analysis, as required by the RHR and the CAA, to
determine if an emission limit more or less stringent than the
presumptive limits is BART.
    EPA disagrees that our approach is not consistent with the RHR and
that we must undergo notice and comment rulemaking to follow our
application of the presumptive BART limits for large coal-fired EGUs.
EPA reiterates that the RHR and the BART Guidelines make clear that the
presumptive limits are rebuttable and may not necessarily be the
appropriate level of control for all EGUs.\11\ Therefore, EPA is not
required to approve every BART determination that meets the presumptive
emission limits, especially when there is no analysis that supports the
state's decision in adopting the presumptive limit instead of a more or
less stringent emission limit.
---------------------------------------------------------------------------

    \11\ 71 FR 60619.
---------------------------------------------------------------------------

    Comment: The BART Rule shows that an alternative analysis is
required only when a source cannot meet the presumptive limits (40 CFR
part 51, appendix Y, section IV.E.5). As such, only when EGUs cannot
meet presumptive NOX limits using current combustion control
technology should other technologies be considered. The plain reading
of the BART Rule is contrary to EPA's proposal to disapprove the
NOX presumptive emission limits adopted for BART by
Arkansas.
    Response: Regarding NOX presumptive emission limits, the
BART Rule provides that:
    ``For coal-fired EGUs greater than 200 MW located at greater than
750 MW power plants and operating without post-combustion controls
(i.e. Selective Catalytic Reduction or Selective Non-Catalytic
Reduction), we have provided presumptive NOX limits,
differentiated by boiler design and type of coal burned. You may
determine that an alternative control level is appropriate based on a
careful consideration of the statutory factors. For coal-fired EGUs
greater than 200 MW located at power plants 750 MW or less in size and
operating without post-combustion controls, you should likewise presume
that these same levels are cost-effective, unless you determine that an
alternative control level is justified based on consideration of the
statutory factors.'' \12\
---------------------------------------------------------------------------

    \12\ 70 FR 39171.
---------------------------------------------------------------------------

    The BART Rule does not contain language stating that an alternative
analysis is required only when a source cannot meet the presumptive
limits. The BART Guidelines provides the following:
    ``Most EGUs can meet these presumptive NOX limits
through the use of current combustion control technology, i.e. the
careful control of combustion air and low-NOX burners. For
units that cannot meet these limits using such technologies, you should
consider whether advanced combustion control technologies such as
rotating opposed fire air should be used to meet these limits.'' \13\
---------------------------------------------------------------------------

    \13\ Appendix Y to Part 51, section IV.E.5.
---------------------------------------------------------------------------

    The intent of this language is to communicate that EPA believes
that the large majority of units can at least meet the presumptive
limits at relatively low costs (i.e. without post-combustion controls).
Because of this, EPA found it appropriate to require EGUs greater than
200 MW located at greater than 750 MW power plants and without post-
combustion controls to at least meet the presumptive limit, unless
based on an evaluation of the statutory factors the State found a more
or less stringent emission limit is appropriate.\14\ The language in
the BART Guidelines should not be misinterpreted to mean that sources
capable of meeting the presumptive limits may forego a BART analysis or
that they need not consider post-combustion controls if they can

meet the NOX presumptive limits with combustion controls.
States have a duty to evaluate the five statutory factors,\15\ and
should consider the level of control that is currently achievable at
the time the BART analysis is conducted.\16\
---------------------------------------------------------------------------

    \14\ 70 FR 39132.
    \15\ See 40 CFR 51.308(e)(1)(ii)(A) and 42 U.S.C. 7491(g)(2).
    \16\ 70 FR 39171.
---------------------------------------------------------------------------

    Comment: The preamble discussion of the BART Rule shows that the
presumptive BART limits were intended to establish a presumptively
acceptable BART determination for large EGUs. The preamble to the
proposed May 5, 2004, and final July 5, 2005, BART Rule demonstrate the
clear intent that the presumptive limits in the BART Rule are BART. In
its proposed disapproval of the Arkansas RH SIP, EPA ignores this.
Nothing in the BART Rule or the preamble to the rule requires that a
source achieve a more stringent emission rate if the emission controls
allow the source to meet the presumptive emission limits. Section
169A(g) of the CAA requires a balancing of the five statutory factors
when a State is determining BART. The preamble to the BART Rule
describes the presumptive limits as reasonable, cost-effective,
extremely likely to be appropriate and likely to result in a
significant degree of visibility improvement. The term ``presumptive
minimum'' or a discussion of controls more stringent than the
presumptive limits is not found in the BART Rule.
    Response: The EPA disagrees that the presumptive BART limits in the
BART Rule were intended to establish BART in every case, as nothing on
the record states that the presumptive limits represent the ``best
available retrofit controls'' for all EGUs at these large power plants.
On the contrary, EPA's BART Rule and the BART Guidelines make clear
that in developing the presumptive emission limits, EPA made many
design and technological assumptions, and that the presumptive limits
may not be BART in every case. As such, the presumption in the BART
Rule is not that the presumptive limits will be BART in every case.
Rather, the presumption in the BART Rule is more accurately interpreted
to be that the controls reflected by the presumptive limits are cost-
effective and will result in considerable visibility improvement.
    EPA's proposed rulemaking on the Arkansas RH SIP did not propose to
require Arkansas's subject to BART sources to achieve an emission rate
more stringent than the presumptive emission limits. Rather, EPA's
proposed rulemaking proposed to disapprove the BART emission limits for
subject to BART sources where the State adopted presumptive emission
limits without conducting a proper BART five factor analysis. Only
after the State conducts a proper evaluation of the five statutory
factors, as required by 40 CFR 51.308(e)(1)(ii)(A) and section 169A(g)
of the CAA, or EPA conducts one in the context of a FIP, will it be
demonstrated whether any of Arkansas's subject to BART sources must
achieve an emission rate more (or less) stringent than the presumptive
limits.
    EPA agrees that section 169A(g) of the CAA requires a balancing of
the five statutory factors when a State is determining BART.\17\ EPA is
also in agreement that the preamble to the BART Rule describes the
presumptive limits as reasonable, cost-effective, extremely likely to
be appropriate and likely to result in a significant degree of
visibility improvement. However, EPA reiterates that the BART Rule does
not state that the presumptive limits will represent the ``best
available retrofit controls'' for all EGUs at these larger power
plants. EPA agrees that the term ``presumptive minimum'' or a
discussion of controls more stringent than the presumptive limits are
not explicitly found in the BART Rule, but the BART Rule does require
that affected sources achieve at least the level of control represented
by the presumptive limits, unless a proper evaluation of the five
statutory factors demonstrates that a different level of control is
BART for the affected sources.
---------------------------------------------------------------------------

    \17\ 42 U.S.C. 7491(g)(2).
---------------------------------------------------------------------------

    Comment: The CAA gives states discretion to make BART
determinations, and while a state may choose to establish a limit that
is more stringent than the presumptive limit, there is nothing in the
BART Rule that would require a state to do so. There are a number of
examples in the BART regulations and in the preambles to the proposed
and final BART Rule, showing that a state has discretion to choose to
demonstrate an alternative control level. The preamble to the BART Rule
recognizes that in some limited cases, where the source cannot meet the
presumptive limit, a state could demonstrate an alternative level of
control. The plain meaning of the BART Rule and the preamble discussion
of the presumptive limits supports a reading of the BART Rule that
discretion rests with a state, not EPA, as to whether the presumptive
limits are reasonable.
    Response: The EPA agrees with the comment that the CAA gives states
discretion to make BART determinations, and that there are examples in
the BART regulations and in the preambles to the proposed and final
BART Rule showing that a state has discretion to choose an alternative
control level after considering the five statutory factors. However,
section 169A(g) of the CAA requires States to consider these statutory
factors in determining BART for affected sources.\18\ If a proper
evaluation of the five statutory factors demonstrates that an emission
limit more or less stringent than the presumptive limit is BART for the
subject to BART source in question, then the State must require the
source to comply with such emission limit. EPA agrees that states have
considerable discretion in making BART determinations, but if the State
has not conducted a proper evaluation of the five statutory factors, as
required by 40 CFR 51.308(e)(1)(ii)(A) and section 169A(g) of the CAA,
the State cannot determine that the presumptive limits are the ``best
available retrofit controls'' for Arkansas's affected sources.
---------------------------------------------------------------------------

    \18\ 42 U.S.C. 7491(g)(2).
---------------------------------------------------------------------------

    Comment: The EPA proposes to reject Arkansas's BART determinations
that rely on the presumptive BART limits codified in EPA's own BART
Guidelines, arguing that states are required to perform a case-by-case
BART analysis in every instance and that they can never rely on the
presumptive limits (76 FR 64201). The BART rules state that the
presumptive limits should be adopted unless the state BART-determining
authority determines that an alternative control level is justified
based on a consideration of the statutory factors (70 FR 39171). Given
the assessment EPA undertook to determine the presumptive BART limits
and that EPA has determined in a formally codified rule that they are
likely to be suitable as BART limits in nearly every circumstance to
which they apply- except to the extent states make a determination
otherwise in a particular case- states properly have discretion to
adopt the presumptive limits. The determination as to whether the
presumptive limits should or should not apply is one that is well
within the discretion of the state. There is little reason for EPA to
have established the presumptive BART limits if states cannot rely on
them. If EPA requires a case-by-case analysis for every facility to
repeatedly test the assumptions underlying the presumptive limits, this
would result in a senseless approach that would vitiate the
establishment of the presumptive limits. This would be contrary to
EPA's own nationally applicable regulations developed as a product of
notice-and-comment

rulemaking. If a specific assessment is required in every case, there
is no reason to have a presumptive limit in the first place.
Regulations, like statutes, should not be interpreted in a manner that
is more stringent than the plain language requires. Where there is no
clear and compelling evidence that presumptive limits cannot be BART
for a given source, EPA should accept state BART determinations that
rely on the presumptive limits.
    Response: The EPA agrees that the State has considerable discretion
in making BART determinations, but if the State has not conducted a
proper evaluation of the five statutory factors, as required by 40 CFR
51.308(e)(1)(ii)(A) and section 169A(g) of the CAA, the State cannot
determine that the presumptive limits are the ``best available retrofit
controls'' for Arkansas's affected sources. With regard to the comment
that there is little reason for EPA to have established presumptive
emission limits if states cannot rely on them, EPA notes that the
purpose of the presumptive limits in the BART Guidelines was to
identify controls that the Agency considered to be generally cost-
effective across all affected units. Because EPA's extensive analysis
found that these controls are generally cost-effective across all
affected units and were anticipated to result in a substantial degree
of visibility improvement, EPA concluded that such units should at
least meet the presumptive limits. Presumptive limits, thus, rather
than being senseless, provide a starting point for a source specific
analysis.
    We agree that regulations, like statutes, should not be interpreted
in a manner that is more stringent than the plain language. However, we
do not agree that our application of the presumptive limit is more
stringent than what is required under the CAA and the RHR. Rather, our
application of the presumptive limit is in keeping with the plain
language of the CAA and the RHR. Under the RHR, presumptive limits were
promulgated to provide a path for states to follow when analyzing BART
for particular EGUs. The BART Rule has presumptive limits that act as a
starting point for the establishment of BART emission limits unless the
state's analysis indicates that an emission limit more or less
stringent than the presumptive limit is required. Please see our
response to other comments for our discussion of the requirements of
the CAA visibility program and the RHR.
    EPA disagrees that we should accept state BART determinations that
rely on the presumptive limits in every case as long as there is no
clear and compelling evidence that presumptive emission limits cannot
be BART for a given source. There is no language indicating this in the
CAA, the RHR, or the BART Guidelines. On the contrary, EPA's BART Rule
and the BART Guidelines make clear that in developing the presumptive
emission limits, EPA made many design and technological assumptions,
and that the presumptive limits may not be BART in every case. EPA's
intent was for the presumptive limits to be used in the State's BART
analysis considering the five factors specified in CAA section
169A(g)(2), and considering the level of control that is currently
achievable at the time that the BART analysis is being conducted.
    Comment: The intent of the RHR was to gain reasonable progress in
visibility improvements in Class I areas, with the ultimate goal being
to achieve background levels of visibility by the year 2064. The BART
Guidelines developed presumptive BART emission limits that are cost-
effective and capable of meeting reasonable progress. ADEQ followed
EPA's BART Guidelines in establishing presumptive limits as BART for
the AEP Flint Creek Boiler No. 1 and Entergy White Bluff Units 1 and 2.
In its proposed rule, EPA ignores its own guidance to utilize
presumptive limits and proposes to go beyond the cost-effective
presumptive limits at Arkansas's EGUs in the near term and to
essentially perform a BACT analysis for these units, as per EPA's PSD
regulations. Going beyond the presumptive limits denies the cost-
effectiveness afforded by the presumptive limits and places an
unnecessary burden on Arkansas electricity ratepayers. EPA's approach
is beyond what is required to comply with the RHR, as requiring
standards more stringent than EPA's own presumptive limits is
unnecessary in order to demonstrate reasonable progress. Implementing
the presumptive limits as BART meets the intent of the RHR and EPA
should accept ADEQ's proposed BART requirements for units subject to
presumptive limits.
    Response: With regard to the comment that the BART Guidelines
developed presumptive emission limits that are cost-effective and
capable of meeting reasonable progress, EPA notes that the RHR states
the following concerning SO2 and NOX presumptive
limits: ``Based on our analysis of emissions from power plants, we
believe that applying these highly cost-effective controls at the large
power plants covered by the guidelines would result in significant
improvements in visibility and help to ensure reasonable progress
toward the national visibility goal.'' \19\
---------------------------------------------------------------------------

    \19\ 70 FR 39131.
---------------------------------------------------------------------------

    The comment appears to suggest that a state's adoption of the
presumptive limits will result in achieving reasonable progress. The
EPA notes that the RHR stated that applying the highly cost-effective
controls reflected by the presumptive limits would result in
significant visibility improvement that would help to ensure reasonable
progress, not that it would necessarily ensure reasonable progress.
Furthermore, for a state to achieve reasonable progress during the
first implementation period, it must also look at point sources beyond
those that are subject to BART as well as at non-point sources and
determine, based on consideration of the four statutory factors under
40 CFR 51.308(d)(1)(i), whether it is reasonable to require these
sources to install additional pollution controls. Therefore, even if a
state satisfies the BART requirements, satisfaction of the reasonable
progress requirements cannot be met by complying with BART requirements
alone. In addition, the EPA notes that the BART Guidelines make clear
that the presumptive limits may not be appropriate for all affected
units.20,21,22
---------------------------------------------------------------------------

    \20\ 70 FR 39131.
    \21\ 70 FR 39132.
    \22\ 71 FR 60619.
---------------------------------------------------------------------------

    The EPA is not ignoring its own guidance to utilize presumptive
limits, as the BART Rule does not suggest the presumptive limits should
be viewed as establishing a safe harbor from more stringent regulation
under the BART provisions. The EPA's proposed rulemaking did not
propose particular emission limits more stringent than the presumptive
limits for Arkansas EGUs. Instead, the EPA's proposed rulemaking stated
that Arkansas must conduct a proper evaluation of the five statutory
factors, as required by 40 CFR 51.308(e)(1)(ii)(A) and section 169A(g)
of the CAA, before determining whether the presumptive emission limits
are the ``best available retrofit controls'' for affected units.
Therefore, the EPA does not believe that requiring the State to conduct
a proper evaluation of the five statutory factors places an unnecessary
burden on Arkansas electricity ratepayers.
    The EPA disagrees with the comment that EPA is requiring Arkansas
to perform a PSD BACT analysis for affected EGUs. The EPA notes the
comment is not specific in terms of explaining what aspect of our
proposed rulemaking led to the belief that EPA is requiring a PSD BACT
analysis for

affected EGUs. However, the proposed BART Rule did note that the
process for a BART analysis is very similar to the BACT review as
described in the New Source Review Workshop Manual (Draft, October
1990).\23\ The proposed BART Rule also explained that although very
similar in process, BART reviews differ in many respects from the BACT
review. The proposed BART Rule explained these differences as follows:
---------------------------------------------------------------------------

    \23\ 69 FR 25218.
---------------------------------------------------------------------------

    ``First, because all BART reviews apply to existing sources, the
available controls and the impacts of those controls may differ from
source to source. Second, the CAA requires you to take slightly
different factors into account in determining BART and BACT * * *
Because of the differences in terminology, the BACT review process
tends to encompass a broader range of factors * * * Finally, for the
BART analysis, there is no minimum level of control required, while any
BACT emission limitation must be at least as stringent as any NSPS that
applies to the source.'' \24\
---------------------------------------------------------------------------

    \24\ 69 FR 25218.
---------------------------------------------------------------------------

    Because of the similarities in the two processes, it is
understandable that there may be some misunderstanding regarding our
proposed rulemaking to mean that EPA is requiring subject to BART
sources to conduct a PSD BACT analysis. Our statement that subject to
BART sources must consider the ``most stringent option (i.e. maximum
level of control each technology is capable of achieving) as well a
reasonable set of options for analysis,'' \25\ may have been
misinterpreted to mean that we are requiring a PSD BACT analysis. We
are not requiring a PSD BACT analysis. As explained in our proposed
rulemaking, the BART Guidelines provide that in identifying all
options, you must identify the most stringent option (i.e. maximum
level of control each technology is capable of achieving) as well as a
reasonable set of options for analysis.\26\ The RHR also provides that
in establishing source specific BART emission limits, the State should
identify and consider in the BART analysis the maximum level of
emission reduction that has been achieved in other recent retrofits at
existing sources in the source category.\27\ Furthermore, the BART
Guidelines state that ``[t]echnologies required as BACT or LAER are
available for BART purposes.'' \28\ The guidelines instruct: ``You are
expected to identify potentially applicable retrofit control
technologies that represent the full range of demonstrated
alternatives. Examples of general information sources are to consider
include: The EPA's Clean Air Technology center, which includes the
RACT/BACT/LAER Clearinghouse (RBLC) * * *'' \29\ Our rulemaking is
consistent with the RHR and the BART Rule, and does not require
Arkansas's subject to BART sources to conduct a PSD BACT analysis.
---------------------------------------------------------------------------

    \25\ See our proposed rulemaking for the Arkansas RH SIP (76 FR
64186).
    \26\ See Appendix Y to Part 51.
    \27\ 64 FR 35740.
    \28\ 70 FR 39,164.
    \29\ 70 FR 39,164.
---------------------------------------------------------------------------

    The EPA disagrees with the comment that EPA's approach in our
proposed rulemaking for the Arkansas RH SIP is beyond what is required
to comply with the RHR and that requiring standards more stringent than
EPA's own presumptive limits is unnecessary in order to demonstrate
reasonable progress. As already explained elsewhere in our response to
other comments, EPA's rulemaking on the Arkansas RH SIP is not
requiring Arkansas affected sources to meet standards more stringent
than the presumptive emission limits. Arkansas must conduct a proper
evaluation of the five statutory factors, as required by 40 CFR
51.308(e)(1)(ii)(A) and section 169A(g) of the CAA, before determining
whether the presumptive emission limits are the ``best available
retrofit controls'' for affected units. Furthermore, 40 CFR
51.308(e)(1)(ii)(A) and section 169A(g) of the CAA require that states
consider the five statutory factors when making BART determinations,
and the State cannot determine whether or not emission limits more
stringent than the presumptive emission limits are necessary to
demonstrate reasonable progress when a proper evaluation of the five
statutory factors has not been conducted.
    Comment: Appendix Y is very clear that when it comes to presumptive
BART NOX emissions limits for qualifying EGUs, Arkansas must
require these EGUs to meet the presumptive BART emissions limits in
Appendix Y. Not only does Arkansas have broad discretion to apply
presumptive NOX limits, but Appendix Y actually requires
this. Arkansas followed this approach in its RH SIP. In its proposed
rule, EPA now claims that the presumptive limits are something
completely different than the straightforward directive contained in
the Code of Federal Regulations, claiming that they are the starting
point in a BART determination and that sources must ``at least'' meet
these emission limits. Using the word ``at least'' implies that
presumptive limits constitute a minimally acceptable degree of control
that would constitute BART. Nothing in the CAA, RHR, or Appendix Y ever
states or implies this. EPA also stated in its proposal for the
Arkansas RH SIP that ``nothing on the record would support the
conclusion that the presumptive limits represent `best available
retrofit controls' for all EGUs at these large power plants'' (76 FR
64201). EPA is attempting to avoid the broad statements it previously
made regarding the applicability of the ``presumptive BART''
NOX emissions limits. EPA's statements in previous
rulemakings demonstrate that in almost all cases, the presumptive BART
limits should apply, and the only instance when they should not apply
is to atypical instances when a source is able to show through a five
factor test that it is not able to meet the presumptive emission rates,
even if the expected control technology were installed. EPA's proposal
for the Arkansas RH SIP also incorrectly claims that in Appendix Y, EPA
simply concluded that it could not reach a generalized conclusion as to
the appropriateness of more stringent controls for categories of EGUs
(76 FR 64201). EPA's failure to recognize the proper role of
presumptive BART NOX emissions limits is arbitrary and
capricious because EPA acted in excess of statutory jurisdiction,
authority, or limitations (North Carolina v. EPA, 531 F.3d 896, 906, DC
Circuit 2008).
    Response: The EPA disagrees that Appendix Y (i.e. the BART
Guidelines) makes the presumptive emission limits mandatory for all
qualifying EGUs. The comment that states have broad discretion to apply
presumptive NOX limits contradicts the comment that the BART
Guidelines require states to adopt the presumptive limits. The BART
Guidelines make clear that the presumptive emission limits are
rebuttable.\30\ Referring to the NOX presumptive emission
limits, the BART Rule states that the presumptive emission limits may
not be appropriate for all sources, as they are ``presumptions only.''
\31\ The presumptive emission limits apply to power plants with a total
generating capacity of 750 MW or greater insofar as these sources are
required to adopt emission limits at least as stringent as the
presumptive limits, unless after considering the five statutory
factors, the State determines that the presumptive emission limits are
not appropriate. Moreover, the CAA, the RHR, and the BART Guidelines do
not

exempt the State from a five factor BART analysis or even provide the
State with discretion to determine whether or not to conduct an
analysis of the five statutory factors when the State has adopted the
presumptive emission limits.
---------------------------------------------------------------------------

    \30\ 71 FR 60619.
    \31\ 70 FR 39134.
---------------------------------------------------------------------------

    We are not claiming that the presumptive emission limits are
anything else than what is contained in the RHR and the BART
Guidelines. With regard to the comment that nothing in the CAA, RHR, or
Appendix Y ever states or implies that the presumptive limits are the
starting point in a BART determination, EPA notes that there is no
mention of the presumptive emission limits in the CAA. Further, in
response to comments on the proposed BART Guidelines that the
presumptive SO2 EGU limits should be more stringent, EPA
justified its decision not to establish more stringent SO2
presumptive limits, by explaining in the preamble to the final BART
Rule that ``[i]f, upon examination of an individual EGU, a State
determines that a different emission limit is appropriate based upon
its analysis of the five factors, then the State may apply a more or
less stringent limit.'' \32\ Similar statements are made elsewhere in
the BART Rule. Clearly, the RHR and the BART Rule do not suggest the
presumptive limits should be viewed as establishing a safe harbor from
more stringent regulation under the BART provisions. EPA stands by the
statement made in its proposed rulemaking on the Arkansas RH SIP that
``nothing on the record would support the conclusion that the
presumptive limits represent `best available retrofit controls' for all
EGUs at these power plants.'' \33\ EPA does not find this statement to
be inconsistent with the RHR and BART Guidelines. As already explained
above, EPA is clear in the BART Rule and the BART Guidelines that the
presumptive limits may not be appropriate for every EGU.\34\
---------------------------------------------------------------------------

    \32\ 70 FR 39132.
    \33\ 76 FR 64201.
    \34\ 70 FR 39131, 39132, and 39134.
---------------------------------------------------------------------------

    EPA disagrees with the comment that the only instance when the
presumptive emission limits should not apply is to atypical instances
when a source is able to show through a five factor test that it is not
able to meet the presumptive emission rates. The comment suggests that
for power plants with a total generating power capacity greater than
750 MW, the RHR and the BART Rule provide that an evaluation of the
five statutory factors for these units is merely a vehicle for
justifying adoption of a BART emission limit less stringent than the
presumptive limit. This is clearly not the intent of the RH regulations
and section 169A(g) of the CAA.\35\ As explained above, in response to
comments on the proposed BART Guidelines that the presumptive
SO2 EGU limits should be more stringent, EPA justified its
decision not to establish more stringent presumptive emission limits by
explaining that after considering the five statutory factors, States
may find that a more or less stringent emission limit is BART.\36\
Similar statements are made elsewhere in the BART Rule. The BART Rule
states the following:
    ``We recognize that while some scrubber units currently achieve
reductions greater than 95 percent, not all units can do so. The
individual units that currently achieve greater than 95 percent control
efficiencies do not necessarily represent the wide range of unit types
across the universe of BART-eligible sources * * * In addition, we note
that the presumption does not limit the States' ability to consider
whether a different level of control is appropriate in a particular
case.'' \37\
---------------------------------------------------------------------------

    \35\ See 40 CFR 51.308(e)(1)(ii)(A) and 42 U.S.C. 7491(g)(2).
    \36\ 70 FR 39132.
    \37\ 70 FR 39132.
---------------------------------------------------------------------------

    Further, in the BART Rule, EPA justified its decision not to
establish presumptive NOX limits based on the use of
selective catalytic reduction (SCR) for units other than cyclone units,
stating the following:
    ``For other units, we are not establishing presumptive limits based
on the installation of SCR. Although States may in specific cases find
that the use of SCR is appropriate, we have not determined that SCR is
generally cost-effective for BART across unit types.'' \38\
---------------------------------------------------------------------------

    \38\ 70 FR 39136.
---------------------------------------------------------------------------

    Therefore, EPA stands by its statement in the proposed rulemaking
on the Arkansas RH SIP that in the BART Guidelines, EPA simply
concluded that it could not reach a generalized conclusion as to the
appropriateness of more stringent controls for categories of EGUs.
    The EPA's application of presumptive BART NOX emissions
limits to Arkansas's RH BART determinations is not arbitrary and
capricious, because EPA is acting in accordance with the CAA and the
RHR. The EPA's disapproval of Arkansas's BART determinations that
adopted the presumptive BART SO2 and NOX emission
limits without conducting a proper five factor BART analysis is a
proper exercise of EPA's authority under the Act. Congress crafted the
CAA to provide for states to take the lead in developing implementation
plans consistent with the laws and regulations, but balanced that
decision by requiring EPA to review the plans to determine whether a
SIP meets the requirements of the CAA. The EPA's review of SIPs is not
limited to support and cooperation in implementation of a state SIP nor
is it to simply approve state decisions. When reviewing state SIPs, EPA
must consider not only whether the state considered the appropriate
factors in making decisions but acted reasonably in doing so. In
undertaking such a review, EPA does not usurp the state's authority but
ensures that such authority is reasonably exercised. EPA has reviewed
Arkansas's BART determinations for NOX that adopted the
presumptive limits without conducting a proper five factor BART
analysis, and we find that Arkansas did not follow the requirements of
the RHR; that is the basis for our disapproval of those BART
determinations. For a more detailed explanation of state and EPA
authority in the development and approval of RH SIPs as well as of how
EPA's action does not encroach on state authority and is consistent
with the CAA and the RHR, please see our response to comments under
section III.F, titled ``Comments on Legal Issues,'' of this final
rulemaking.
    Comment: The EPA's treatment of presumptive limits in its proposed
partial disapproval of AR RH SIP is inconsistent with EPA's BART
Guidelines. EPA departed from the BART Guidelines and made the use of
presumptive limits meaningless when it disapproved BART determinations
for Entergy's Lake Catherine Unit 4 and White Bluff Units 1 and 2 that
adopt the presumptive limits. When EPA departs from the BART
Guidelines, it is going beyond the scope of the CAA's visibility
protection program. For certain categories of EGUs, EPA's BART
Guidelines provide presumptive limits that the states rely upon in
making BART determinations. The presumptive limit framework outlined in
the BART Guidelines is intended to function like presumptive evidence
in litigation where the evidence is received and treated as sufficient
until it is discredited. Presumptive limits should represent BART until
and unless they are rebutted. This is not how EPA approached
presumptive limits in reviewing the Arkansas RH SIP. The BART
Guidelines provide that if a state wishes to do a case-by-case BART
then there are presumptive levels of controls for SO2 and
NOX that can be adopted for certain EGUs that the state
finds are

subject to BART. This is what Arkansas did and should be approved by
EPA.
    Response: The EPA disagrees that the EPA's treatment of the
presumptive limits in its proposed rulemaking on the Arkansas RH SIP is
inconsistent with EPA's BART Guidelines and made use of the presumptive
limits meaningless. EPA notes that Entergy Lake Catherine Unit 4 is
currently permitted to burn natural gas and fuel oil. EPA's BART
Guidelines do not establish presumptive emission limits for units that
burn natural gas and/or fuel oil, therefore the ADEQ did not adopt any
presumptive limits for Entergy Lake Catherine Unit 4. With regard to
Entergy White Bluff Units 1 and 2, as stated in our proposed rulemaking
on the Arkansas RH SIP, the purpose of the presumptive limits in the
BART Guidelines was to identify controls that the Agency considered to
be generally cost-effective across all affected units. Because EPA's
extensive analysis found that these controls are generally cost-
effective across all affected units and were anticipated to result in a
substantial degree of visibility improvement, EPA concluded that such
units should at least meet the presumptive limits, unless a more or
less stringent limit is found to be BART after the state considers the
five statutory factors. EPA's intent was for these generally cost-
effective controls to be used in the State's BART analysis considering
the five factors specified in CAA section 169A(g)(2), and considering
the level of control that is currently achievable at the time that the
BART analysis is being conducted. Further, 40 CFR 51.308(e)(1)(ii)(A)
requires that States identify the level of control representing BART
after considering the five statutory factors set out in CAA section
169A(g).\39\
---------------------------------------------------------------------------

    \39\ 70 FR 39158.
---------------------------------------------------------------------------

    We disagree that the presumptive limits should represent BART until
and unless they are rebutted. We reiterate that nothing on the record
states that the presumptive limits represent the ``best available
retrofit controls'' for all EGUs at these large power plants. On the
contrary, EPA's BART Rule and the BART Guidelines make clear that in
developing the presumptive emission limits, EPA made many design and
technological assumptions, and that the presumptive limits may not be
BART in every case.
    While the BART Guidelines provide that there are presumptive levels
of controls for SO2 and NOX that can be adopted
for certain EGUs that the state finds are subject to BART, this is true
only after the state has considered the five statutory factors to
determine whether a more or less stringent emission limit is BART. In
the BART Guidelines, EPA noted that the presumptive limits represented
current control capabilities at the time the BART Rule was promulgated,
and that we expected that scrubber technology would continue to improve
and control costs continue to decline.\40\ Therefore, in their
evaluation of the five statutory factors, states must consider the
level of control that is currently achievable at the time the BART
analysis is being conducted.
---------------------------------------------------------------------------

    \40\ 70 FR 39144.
---------------------------------------------------------------------------

    The presumptive limit framework could be compared to the
presumptive evidence in litigation. However, the comment
mischaracterizes the role of presumptive evidence in litigation as
simply to be received and treated as sufficient until it is
discredited. Presumptive evidence is circumstantial evidence that
creates belief by showing surrounding circumstances which logically
lead to a conclusion of fact. At trial, many forms of evidence are
submitted including circumstantial evidence. All forms of evidence that
are admitted in court are reviewed and considered before a decision is
made. While presumptive evidence may meet the sufficiency requirement
for admission in court, this does not mean that it is looked at alone
without review of the other admitted evidence. Presumptive evidence
does not trump other forms of evidence. It is just a type of evidence
that is reviewed in reaching a court decision. Like presumptive
evidence, presumptive limits are one line of analysis for reaching a
decision. Like presumptive evidence in the court room, presumptive
limits are not the only limit that is looked at when performing the
five factor BART analysis. Presumptive limits do not preempt states
from conducting the BART analysis nor do they preclude the evaluation
of other emission limits to help the state reach its BART
determination.
    Comment: The EPA should approve the Arkansas RH SIP in its entirety
and specifically with regards to Arkansas adoption of presumptive
limits in its BART determinations. Modeling conducted by Arkansas and
CENRAP demonstrates that Arkansas's adoption of the presumptive limits
is satisfactory to make reasonable progress toward the national goal by
2018 and ultimately to achieve the national goal prior to 2064.
    Response: Presumptive emission limits apply to power plants with a
total generating capacity of 750 MW or greater insofar as these sources
are required to adopt emission limits at least as stringent as the
presumptive limits, unless after considering the five statutory
factors, the State determines that the presumptive emission limits are
not appropriate. The RHR and the BART Guidelines make clear that the
presumptive limits will not necessarily be the appropriate level of
control for all EGUs. Therefore, EPA is not required to approve a
state's submitted presumptive emission limits in every instance for
every EGU as BART. For the reasons presented in our proposed
rulemaking, and as further explained in our response to comments, EPA
stands by its partial approval and partial disapproval of the BART
determinations in the Arkansas RH SIP.
    States are required to satisfy all BART requirements in this first
implementation period regardless of whether modeling demonstrates that
the state will make reasonable progress by 2018 and meet the national
goal by 2064. As described in our proposed rulemaking on the Arkansas
RH SIP, we find that in adopting the SO2 and NOX
presumptive limits for the AEP Flint Creek Boiler No. 1 and Entergy
White Bluff Units 1 and 2 without conducting a proper evaluation of the
five statutory factors, as required by 40 CFR 51.308(e)(1)(ii)(A) and
section 169A(g) of the CAA, Arkansas did not satisfy all the BART
requirements for these subject to BART sources. Furthermore, EPA notes
that the CENRAP modeled the projected visibility conditions anticipated
at each Class I area in 2018. The CENRAP modeling is based on emissions
reductions expected to result from Federal, state, and local control
programs that are either currently in effect or with mandated future-
year emission reduction schedules that predate 2018. The CENRAP
modeling itself did not show that already mandated controls are
expected to attain natural visibility conditions by 2064. Rather, the
rate of visibility improvement anticipated by the CENRAP modeling in
2018, if sustained, will result in a return to natural visibility prior
to 2064. The comment that Arkansas is expected to ultimately achieve
the national goal prior to 2064 assumes that the same level of
reductions of visibility-impairing pollutants that is expected to occur
during the first implementation period ending in 2018 will increasingly
occur during each implementation period until the final implementation
period ending in 2064. However, there is no guarantee that this will
occur. The Arkansas RH SIP addresses implementation of the RHR only up
to the end of the first implementation

period ending in 2018. Therefore, EPA disagrees that we should approve
Arkansas's adoption of the presumptive limits on the basis that
modeling demonstrates that the State's adoption of the presumptive
limits is satisfactory to make reasonable progress toward the national
goal by 2018 and ultimately to achieve the national goal prior to 2064.
    Comment: Under the BART Guidelines, presumptive limits were
established as a default requirement where the presumption would apply
unless the state has persuasive evidence that an alternative
determination is justified. According to EPA, the presumptive limits
reflect highly cost-effective controls that are extremely likely to be
appropriate for all power plants subject to BART but may be deviated
from if a state determines that a different emission limit is
appropriate based upon its analysis of the five factors. 76 FR 39131-
32.
    Response: As reflected in our previous responses to similar
comments, the proper interpretation of the BART Rule and BART
Guidelines is that presumptive limits are the ``rebuttable'' starting
point rather than the ``default requirement'' in making BART
determinations. Referring to the NOX presumptive emission
limits, the BART Rule states that the presumptive emission limits may
not be appropriate for all sources, as they are ``presumptions only.''
\41\ EPA notes that presumptive emission limits apply to power plants
with a total generating capacity of 750 MW or greater insofar as these
sources are required to adopt emission limits at least as stringent as
the presumptive limits, unless after considering the five statutory
factors, the State determines that the presumptive emission limits are
not appropriate for BART.
---------------------------------------------------------------------------

    \41\ 70 FR 39134.
---------------------------------------------------------------------------

    EPA agrees that the BART Rule and the BART Guidelines provide that
presumptive limits reflect controls that the Agency considered to be
generally cost-effective across all affected units. Because EPA's
extensive analysis found that these controls are generally cost-
effective across all affected units and were anticipated to result in a
substantial degree of visibility improvement, they may likely be
appropriate for all Arkansas power plants subject to BART, but Arkansas
must establish different BART emission limits if an evaluation of the
five statutory factors reveals that such emission limit is appropriate.
However, as discussed in our proposed rulemaking, Arkansas did not
conduct a proper evaluation of the five statutory factors for its
sources. Therefore, it is not possible to know whether the presumptive
emission limits or an alternative emission limit is BART for the
affected sources.
    Comment: The approach in EPA's proposed rule to presumptive limits
as a starting point is inconsistent with the BART Guidelines. The
Guidelines do not state that presumptive limits are a starting point
for a BART determination, but instead establish a presumption in favor
of the presumptive limits. Presumptive limits serve no purpose if their
adoption does not presume compliance with the applicable regulations.
The EPA's inconsistent application of its own guidelines fosters
regulatory uncertainty among the EGU industry.
    Response: The EPA disagrees that our approach to presumptive limits
as a starting point in EPA's proposed rule is inconsistent with the
BART Guidelines and that the presumptive limits serve no purpose if
their adoption does not presume compliance with the regulations. As
stated in our proposed rulemaking on the Arkansas RH SIP, the purpose
of the presumptive limits in the BART Guidelines was to identify
controls that the Agency considered to be generally cost-effective
across all affected units. Because EPA's extensive analysis found that
these controls are generally cost-effective across all affected units
and were anticipated to result in a substantial degree of visibility
improvement, EPA concluded that such units should at least meet the
presumptive limits. EPA's intent was for these generally cost-effective
controls to be used in the State's BART analysis considering the five
factors specified in CAA section 169A(g)(2), and considering the level
of control that is currently achievable at the time that the BART
analysis is being conducted. The BART Rule makes clear that the
presumptive emission limits in the BART Guidelines are rebuttable.\42\
Referring to the NOX presumptive emission limits, the BART
Rule states that the presumptive emission limits may not be appropriate
for all sources, as they are ``presumptions only.'' \43\ Further, in
response to comments on the proposed BART Guidelines that the
presumptive SO2 EGU limits should be more stringent, EPA
explained in the preamble to the final BART Rule that ``[i]f, upon
examination of an individual EGU, a State determines that a different
emission limit is appropriate based upon its analysis of the five
factors, then the State may apply a more or less stringent limit.''
\44\ Similar statements are made elsewhere in the BART Rule. It is
important that, in analyzing the technology, states take into account
the most stringent emission control level that the technology is
capable of achieving. States should be sure to consider the level of
control that is currently achievable at the time that the BART analysis
is being conducted. Thus, the BART Guidelines require that potential
emission limits that are more stringent than the presumptive limits
must be examined as part of the BART determination.
---------------------------------------------------------------------------

    \42\ 71 FR 60619.
    \43\ 70 FR 39134.
    \44\ 70 FR 39132.
---------------------------------------------------------------------------

    Comment: The EPA's proposed disapproval of Arkansas's adoption of
presumptive limits for some of its BART determinations is inconsistent
with EPA's acceptance of presumptive limits in other states' BART
determinations such as Kansas, North Dakota, and Oklahoma. The EPA has
not identified a rationale or reason for this inconsistency. The lack
of consistency in its analyses for states' RH SIPs is a cause of
concern. Applying different standards and/or rendering different
decisions on similar SIPs when there is no basis for differentiation is
by definition arbitrary and capricious, and therefore invalid. Instead
of arbitrarily applying different standards, EPA should use its own
guidelines to implement the RH program on a consistent, cost-effective
basis. For Kansas, the EPA approved the Kansas RH SIP including the
adoption of SO2 and NOX presumptive limits for
non-oil or gas-fired units similar in design and capacity to Arkansas's
units. The Kansas RH SIP also included language, which EPA approved,
that presumptive limits are cost effective in most cases, and if a
facility proposed controls at or beyond the presumptive limits, it need
not take into account the remaining statutory factors as BART will be
met. In addition, the SIP also stated that allowing facilities to use
presumptive limits to meet BART is within its authority under the RH
program. This contradicts the EPA's proposed disapproval of the
Arkansas RH SIP where EPA states that presumptive limits are the
starting point in a BART determination for these units. For North
Dakota, EPA proposed to approve the BART determinations that
SO2 and NOX presumptive limits is BART for
facilities that are similar in use of fuel and capacity to Arkansas's
units. For Oklahoma, the EPA has proposed to approve those portions of
Oklahoma's SIP which adopt the presumptive emissions limits for
NOX set forth in the Guidelines as BART for the subject

units. This contradicts EPA's approach for this proposed rule since EPA
is proposing to disapprove the NOX BART presumptive limit
for Arkansas's units even though the units are similar in design and
capacity to the subject units in Oklahoma and Arkansas considered the
same BART factors as Oklahoma. EPA's simultaneous proposed approval of
other states' SIPs which use presumptive limits in a manner similar to
Arkansas and proposed disapproval of those portions of Arkansas's SIP
demonstrates that EPA is acting inconsistently and has exceeded its
limited authority in implementation of the visibility protection
program.
    Response: The EPA disagrees that there is an inconsistency between
our approach to presumptive limits in our proposed rulemaking on the
Arkansas RH SIP and that in our proposed rulemaking on the North Dakota
RH SIP and final rulemakings on the Kansas and Oklahoma RH SIPs. Our
action on the Arkansas RH SIP is not arbitrary and capricious.
    In the Arkansas RH SIP, the State adopted the NOX and
SO2 presumptive emission limits for BART without conducting
any form of BART analysis for AEP Flint Creek Boiler No. 1. For Entergy
White Bluff Units 1 and 2, the State conducted a five factor BART
analysis for SO2 and NOX, which we find does not
appropriately consider all five statutory factors at 40 CFR
51.308(e)(1)(ii)(B); as such, EPA proposed to disapprove the State's
determination that the presumptive SO2 and NOX
emission limits are BART for these two units.\45\ As explained in more
detail in our proposed rulemaking, the factors that EPA is finding were
not appropriately considered in the NOX and SO2
BART analyses for White Bluff Units 1 and 2 are the available control
technology and the cost and visibility impact of controls beyond the
presumptive limits. For NOX BART, Arkansas evaluated only
combustion controls to achieve the NOX presumptive emission
limit. For SO2 BART, Arkansas evaluated both combustion and
post-combustion controls, but evaluated the cost and visibility impact
of operating post-combustion controls (i.e. wet and dry scrubbers) to
achieve theSO2 presumptive emission limit only. As explained
in our proposed rulemaking, Arkansas did not evaluate NOX
and SO2 controls to achieve emission limits beyond the
presumptive limits, and we believe it is very likely that a proper five
factor analysis would demonstrate that controls that achieve
NOX and SO2 emission limits more stringent than
presumptive limits are cost-effective for White Bluff Units 1 and 2.
Therefore, we are disapproving the SO2 and NOX
presumptive emission limits for Flint Creek Boiler No. 1 and White
Bluff Units 1 and 2 not because the State adopted the presumptive
emission limits, but rather because the State did not conduct a proper
evaluation of the five statutory factors when making these BART
determinations.
---------------------------------------------------------------------------

    \45\ 76 FR 64206.
---------------------------------------------------------------------------

    In contrast, in our evaluation of the Oklahoma RH SIP, EPA found
that Oklahoma conducted proper BART analyses before determining that
NOX presumptive limits are BART for some sources. In our
final rulemaking action on the Oklahoma RH SIP, EPA approved the
State's NOX BART determinations for Units 1 and 2 at OG&E
Sooner; Units 4 and 5 at OG&E Muskogee; and Units 3 and 4 at AEP/PSO
Northeastern. For each of these sources, the State made its
NOX BART determination based on an evaluation of a number of
controls, including post-combustion controls operated to achieve an
emission limit beyond the NOX presumptive limit. Based on an
evaluation of the five statutory factors, Oklahoma determined that the
NOX presumptive limit is BART for these sources. In our
action on the Oklahoma RH SIP, we approved the NOX
presumptive limits as BART for these sources because Oklahoma's
NOX BART analyses were appropriate and met the requirements
of the RHR and CAA.
    In our proposed approval of the Kansas RH SIP, we noted that each
of Kansas's subject to BART sources are EGUs greater than 200 MW in
capacity and located at power plants with a total capacity greater than
750 MW, which are units for which EPA established presumptive BART
emission limits.\46\ Consistent with our proposed rulemaking on the
Arkansas RH SIP, in our proposed rulemaking for Kansas, we stated that
such units must as a general matter at least meet the presumptive
emission limits as described in the BART Guidelines, unless an
evaluation of the five statutory factors demonstrated that an
alternative level of control was appropriate.\47\ The State of Kansas
performed an evaluation of the five statutory factors for each source
subject to BART, evaluating the costs and visibility impact of both
combustion and post-combustion controls.\48\ In fact, the Kansas BART
evaluation for some units resulted in the adoption of BART emission
limits more stringent than the NOX and SO2
presumptive limits.\49\ Based on an evaluation of the five factors, the
State of Kansas determined, and EPA proposed to approve the
NOX and SO2 presumptive limits for some units.
During the public comment period for our proposed approval of the
Kansas RH SIP, we received comments stating that the Kansas RH SIP was
incomplete and insufficient because the State did not evaluate the cost
and visibility improvement resulting from the most stringent emission
limit capable of being achieved by the various SO2 and
NOX controls considered for these units. Subsequently, the
State provided EPA information on the cost and visibility impact of
operating the various NOX and SO2 control
technologies considered by the State at an emission rate more stringent
than the presumptive limits. The information provided by the State
demonstrated that operation of these controls to achieve an emission
limit more stringent than the presumptive limit would result in high
costs and very low visibility improvement, and thereby not be cost-
effective. Based upon its evaluation of the State's five factor
supplemented analysis, EPA agreed with Kansas that it is reasonable to
determine that the cost of further control beyond presumptive limits is
not warranted and finalized its proposed approval of the Kansas RH SIP
without changes.\50\ In particular, for the Westar Jeffrey Units 1 and
2, EPA agreed with the State of Kansas that given the very low
visibility improvement modeled for the additional SO2
control (i.e. operating a scrubber at a control efficiency that would
achieve an emission rate of 0.05 lb/MMBtu instead of the presumptive
emission rate of 0.15 lb/MMBtu), it is not reasonable to establish an
SO2 emission limit more stringent than the presumptive
limit. Arkansas has not provided EPA with information demonstrating
that operation of SO2 and NOX controls to achieve
an emission limit more stringent than the presumptive limits is not
cost-effective for Flint Creek Boiler No. 1 and White Bluff Units 1 and
2. Since controls capable of achieving a more stringent emission limit
than the NOX and SO2 presumptive limits have been
found to be technically feasible and cost-effective at similar sources,
the State must evaluate these controls in its BART analysis. Therefore,
EPA's final approval of the NOX and SO2
presumptive limits for some EGUs in Kansas is not inconsistent with our
proposed disapproval of the NOX and

SO2 presumptive limits for White Bluff Units 1 and 2 and
Flint Creek Boiler No. 1. With regard to the comment that the Kansas RH
SIP included language that that if a subject facility proposes controls
at or beyond the presumptive limits then BART will be met and that
allowing facilities to use presumptive limits to meet BART is within
the State's authority under the RH program, EPA notes that although the
Kansas RH SIP did include such language, EPA did not approve or propose
to approve the BART determinations by Kansas based on such reasoning.
EPA notes that Kansas supplemented its BART evaluation by providing
additional information on the costs and visibility impacts associated
with various NOX and SO2 control technologies.
This additional information constituted an important part of the basis
for EPA's approval of the Kansas RH SIP. As a general matter, in
evaluating a SIP submittal, EPA considers the state's rationale for its
determinations but reaches a decision as to whether a SIP meets the
relevant statutory and regulatory requirements based on consideration
of other factors as well. EPA's approval of a SIP does not mean that
EPA has determined that every statement or analysis provided by the
state was appropriate or reasonable or that EPA agrees with the state's
interpretation of the relevant legal requirements. Furthermore, the
preamble to our proposed rulemaking on the Kansas RH SIP states that as
presumptive units, each of Kansas' five subject to BART units ``must as
a general matter at least meet the presumptive emission limits as
described in the BART Guidelines.'' \51\ This is consistent with
statements made in the preamble to our proposed rulemaking on the
Arkansas RH SIP. EPA believes that our approach to presumptive limits
in our final action on the Kansas RH SIP is consistent with that in our
action on the Arkansas RH SIP.
---------------------------------------------------------------------------

    \46\ 76 FR 52616.
    \47\ 76 FR 52616.
    \48\ 76 FR 52617.
    \49\ 76 FR 80754.
    \50\ 76 FR 80754.
    \51\ 76 FR 52604, at 52616.
---------------------------------------------------------------------------

    While the SO2 controls evaluated by North Dakota for the
Great River Energy Coal Creek Station Units 1 and 2 are not expected to
achieve an emission limit more stringent than the SO2
presumptive emission limit, EPA disagrees that our approach to
presumptive limits in our proposed action on North Dakota's BART
determinations for the Coal Creek Station Units 1 and 2 is inconsistent
with that in our proposed action on Arkansas's BART determinations for
Flint Creek Boiler 1 and White Bluff Units 1 and 2. First of all, the
SO2 presumptive limits do not apply to North Dakota's Coal
Creek Station Units 1 and 2, as the presumptive limits do not apply to
coal-fired units with existing SO2 post-combustion
controls.\52\ The Coal Creek Station Units 1 and 2 have existing wet
scrubbers, and as such, the cost effectiveness (on a dollar/tons
reduced basis) of additional controls and/or upgrades to the existing
scrubbers may not be as cost-effective as the installation and
operation of a new scrubber would be at a unit with no existing post-
combustion controls (as is the case with Arkansas's Flint Creek Boiler
No. 1 and White Bluff Units 1 and 2). In addition, we note that the
Coal Creek Station Units 1 and 2 burn pulverized lignite coal, while
Flint Creek Boiler No. 1 burns low sulfur western coal (i.e. sub-
bituminous coal) and White Bluff Units 1 and 2 burn sub-bituminous and
bituminous coal. Lignite coal generally has higher sulfur content than
sub-bituminous and bituminous coal, and therefore, its combustion
produces a greater amount of SO2 emissions. As such, the
operation of a given control technology, in this case a wet scrubber,
at a lignite firing unit (such as North Dakota's Coal Creek Station
Units 1 and 2) may not necessarily achieve an emission limit as
stringent as that capable of being achieved at a unit burning sub-
bituminous and/or bituminous coal (such as Arkansas's Flint Creek
Boiler No. 1 and White Bluff Units 1 and 2). In light of the above, we
believe that our approach to presumptive limits in our proposed action
on the North Dakota RH SIP is not inconsistent with that in our
proposed action on the Arkansas RH SIP.
---------------------------------------------------------------------------

    \52\ The BART Guidelines provide that States must require 750 MW
power plants to meet specific control levels for SO2 of
either 95% control or 0.15 lb/MMBtu, for each EGU greater than 200
MW that is currently uncontrolled unless you determine that an
alternative control level is justified based on a careful
consideration of the statutory factors (Appendix Y to Part 51,
section IV.E.4.).
---------------------------------------------------------------------------

    As articulated in our proposed rulemaking on the North Dakota RH
SIP, the Great River Energy Stanton Unit 1 is located at a 188 MW power
plant. Therefore, presumptive NOX and SO2
emission limits do not apply to Stanton Unit 1. As shown in Tables 7
and 8 of our proposed rulemaking on the North Dakota RH SIP, in its
five factor analyses for SO2 for this unit (for both the
lignite and the Powder River Basin coal firing scenarios), North Dakota
considered a number of post-combustion control options, several of
which were expected to achieve an emission limit more stringent than
the SO2 presumptive limit, including one of which would
achieve 95% control efficiency.\53\ Based on its consideration of the
five statutory factors, North Dakota determined that an SO2
emission limit of 0.24 lb/MMBtu for lignite burning and an emission
limit of 0.16 lb/MMBtu for Powder River Basin coal burning is BART for
SO2. For NOX for Stanton Unit 1, North Dakota
evaluated both combustion and post-combustion controls for both the
lignite and Powder River Basin Coal burning scenarios. In its
evaluation of controls, North Dakota considered the operation of
selective non-catalytic reduction (SNCR) to achieve a control
efficiency of 90% for lignite burning and 88% for Powder River Basin
coal burning, which corresponds to an emission limit beyond the
NOX presumptive limit. Based on its consideration of the
five statutory factors, North Dakota determined that a NOX
emission limit of 0.29 lb/MMBtu for lignite burning and 0.23 lb/MMBtu
for Powder River Basin coal burning is BART for NOX. In our
proposal, we did not identify any flaws with North Dakota's BART
analyses for NOX and SO2 for this unit, and
proposed to approve North Dakota's BART determinations. EPA's approach
to presumptive limits in our proposed action on North Dakota's BART
determinations for the Great River Energy Stanton Unit 1is not
inconsistent with that in our proposed action on the Arkansas BART
determinations for White Bluff Unit 1 and 2 and Flint Creek Boiler No.
1 because North Dakota considered controls beyond the NOX
and SO2 presumptive emission limits. This was not done by
Arkansas in the NOX and SO2 BART analyses for
White Bluff Units 1 and 2 and Flint Creek Boiler No. 1. Furthermore,
presumptive NOX and SO2 emission limits do not
apply to Stanton Unit 1.
---------------------------------------------------------------------------

    \53\ 76 FR 58570, at 58586 and 58587.
---------------------------------------------------------------------------

    North Dakota's Minnkota Power Cooperative Milton R. Young Station
Unit 1 has no existing SO2 post-combustion controls, while
Unit 2 has an existing wet scrubber for control of SO2. As
such, the SO2 presumptive limits don't apply to Unit 2. As
shown in Table 12 of our proposed rulemaking on the North Dakota RH
SIP, for Milton R. Young Station Unit 1, North Dakota considered post
combustion controls that were expected to achieve 95% control
efficiency, which corresponds to an emission limit more stringent than
the SO2 presumptive limit.\54\ As shown in Table 13 of our
proposed rulemaking on the North Dakota RH SIP, for Milton R. Young
Station Unit 2 North Dakota considered upgrades to the existing wet
scrubber that were expected to achieve

95% control efficiency, which corresponds to an emission limit beyond
the SO2 presumptive limit.\55\ In our proposed rulemaking on
the North Dakota RH SIP, we did not identify any flaws with North
Dakota's SO2 BART analysis for these units. In light of the
fact that SO2 presumptive limits don't apply to Milton R.
Young Station Unit 2 and that North Dakota evaluated controls to
achieve 95% control efficiency for both Units 1 and 2, which
corresponds to an emission limit more stringent than the SO2
presumptive limit, we believe that EPA's approach to presumptive limits
in our proposed action on North Dakota's BART determinations for
Minnkota Power Cooperative Milton R. Young Station Unit 1 and 2 is not
in conflict with that in our proposed action on Arkansas's BART
determinations for White Bluff Units 1 and 2 and Flint Creek Boiler No.
1.
---------------------------------------------------------------------------

    \54\ 76 FR 58570, at 58589.
    \55\ 76 FR 58570, at 58590.
---------------------------------------------------------------------------

    While the SO2 controls evaluated by North Dakota for the
Basin Electric Power Cooperative Leland Olds Station Units 1 and 2,
which are located at a 656 MW coal fired power plant, are not expected
to achieve an emission limit more stringent than the SO2
presumptive emission limit, EPA disagrees that our approach to
presumptive limits in our proposed action on North Dakota's BART
determinations for the Leland Olds Station Unit 1 and 2 is inconsistent
with that in our proposed action on Arkansas's BART determinations for
Flint Creek Boiler No. 1 and White Bluff Units 1 and 2. As with the
Great River Energy Stanton Unit 1, the SO2 and
NOX presumptive limits do not apply to North Dakota's Leland
Olds Station Units 1 and 2, as the presumptive limits do not apply to
coal fired power plants with a total generating capacity less than 750
MW.\56\ As shown in Table 17 of our proposed rulemaking on the North
Dakota RH SIP, for Leland Olds Station Unit 1 North Dakota considered
both NOX combustion and post-combustion controls capable of
achieving 80% control efficiency, which corresponds to an emission
limit much more stringent than the NOX presumptive
limit.\57\ In our proposed rulemaking on the North Dakota RH SIP, we
did not identify any flaws with North Dakota's BART analysis for
NOX for Unit 1 and proposed to approve North Dakota's
determination that BART for NOX is 0.19 lb/MMBtu for Leland
Olds Station Unit 1. EPA's approach to presumptive limits in our
proposed action on North Dakota's BART determination for NOX
for the Leland Olds Station Unit 1 is not inconsistent with that in our
proposed action on Arkansas's BART determinations for Flint Creek
Boiler No. 1 and White Bluff Units 1 and 2 because in its evaluation of
controls for NOX for Unit 1 (for which we did not propose to
find any flaws), North Dakota considered controls beyond the
NOX presumptive emission limits. This was not done by
Arkansas in the NOX and SO2 BART analyses for
White Bluff Units 1 and 2 and Flint Creek Boiler No. 1. Furthermore,
the NOX and SO2 presumptive limits do not apply
at the Leland Olds Station Units 1 and 2.
---------------------------------------------------------------------------

    \56\ The BART Guidelines provide that States must require 750 MW
power plants to meet specific control levels for SO2 of
either 95% control or 0.15 lb/MMBtu, for each EGU greater than 200
MW that is currently uncontrolled unless you determine that an
alternative control level is justified based on a careful
consideration of the statutory factors (Appendix Y to Part 51,
section IV.E.4.).
    \57\ 76 FR 58570, at 58593.
---------------------------------------------------------------------------

    In summary, EPA disagrees that there is an inconsistency between
our approach to presumptive limits in our proposed rulemaking on the
Arkansas RH SIP and that in our proposed rulemaking on the North Dakota
RH SIP and final rulemakings on the Kansas and Oklahoma RH SIPs.
    Comment: The process used by the State of Arkansas in adopting the
presumptive emission limits set forth in EPA's BART Guidelines as BART
for Entergy White Bluff was improper. The record reflects that neither
ADEQ nor the APCEC conducted its analysis of the statutory factors
required to establish BART, but merely adopted EPA's presumptive limits
as proposed by the owners and operators of the Entergy White Bluff
Units 1 and 2. The record does not reflect that any analysis was done
by ADEQ to determine if the estimated operating cost and the projected
cost per deciview (dv) improvement for wet scrubbing control technology
for the White Bluff plant were realistic, whether those costs were
consistent with the cost assumptions underlying EPA's development of
presumptive limits in the BART Guidelines, or whether other options
were available to address RH concerns or whether existing control
technology at White Bluff was sufficient. Moreover, after Arkansas's RH
SIP was adopted by the APCEC, Entergy submitted a revised 2008 BART
analysis to ADEQ that reflected a more than 300% increase in the costs
of compliance for the White Bluff facility. After this, Entergy filed
with the Arkansas Public Service Commission a claim that the RHR
compliance costs for White Bluff would exceed $1 billion. Nothing in
the record indicates that Arkansas considered these increased costs in
establishing BART emission limits for Entergy White Bluff in the
Arkansas RH SIP. In addition, EPA was not aware or did not consider
Entergy's 2008 revised BART analysis for White Bluff.
    Response: The EPA agrees that the Arkansas BART determination for
Entergy White Bluff Units 1 and 2 was flawed. As described in our
proposed rulemaking, the State failed to adequately consider controls
and BART emission limits beyond the presumptive limits and the State
did not determine that the general assumptions underlying the EPA's
analysis of presumptive limits in its 2005 BART Rule were not
applicable to White Bluff. As to the revised 2008 BART analysis for
White Bluff, which the source submitted to ADEQ, EPA notes that the
Arkansas RH SIP submittal that EPA received from the State on September
23, 2008, contains a BART analysis for White Bluff dated December
2006.\58\ The Arkansas RH SIP submittal does not contain the revised
2008 BART analysis for White Bluff, nor was the revised 2008 BART
analysis for White Bluff ever submitted to EPA by the State as an
official RH SIP revision. Given this, EPA has not taken the revised
analysis into account in evaluating the Arkansas RH SIP.
---------------------------------------------------------------------------

    \58\ See ``BART Analysis for the White Bluff Steam Electric
Station,'' dated December 2006 and prepared by Robert Paine, found
in Appendix 9.3A of the Arkansas RH SIP.
---------------------------------------------------------------------------

    Comment: The process used by the State of Arkansas in adopting the
presumptive emission limits set forth in EPA's Guidelines as BART for
Flint Creek Boiler No. 1 was improper. For the Flint Creek facility,
there is no BART analysis or other information that indicates the
actual costs of various control technologies or other options for
addressing RH concerns, and there is nothing in the record that
reflects that ADEQ considered the actual costs of controls at the Flint
Creek plant in its determination of BART for this facility. This is due
to Arkansas's improper adoption and reliance on EPA's presumptive
limits.
    Response: The EPA agrees that the process used by Arkansas in
adopting the NOX and SO2 presumptive emission
limits set forth in EPA's Guidelines for BART for Flint Creek Boiler
No. 1 was improper. The State did not consider the costs of controls or
any of the other statutory factors, as required under the RHR and the
Act, when making its BART determinations for this source. For this
reason we are finalizing our proposed disapproval of the States'
NOX

and SO2 BART determinations for Flint Creek Boiler No. 1.
    Comment: The EPA approval of the PM BART determination for Flint
Creek Boiler No. 1 in which BART analysis was not conducted because
visibility impacts are minimal contradicts EPA's later rejection of
presumptive limits for failure to conduct a full BART analysis for
NOX and SO2 at the same facility.
    Response: Our proposed approval of the PM BART determination for
the AEP Flint Creek Boiler No. 1 does not contradict our proposed
disapproval of the NOX and SO2 presumptive limits
for the same source. In our review of the Arkansas RH SIP, we evaluated
the determination by ADEQ that no additional PM controls are required
at the Flint Creek Boiler No. 1. ADEQ's determination was based on the
pre-control modeling performed by ADEQ and a review of AEP SWEPCO's
statement that the PM visibility modeling did not ``trip the BART
impact threshold.'' We reviewed the pre-control modeling preformed by
ADEQ using the 24-hr actual maximum emissions from the baseline period.
The modeling results in Appendix 9.2B of the Arkansas RH SIP and
presented in Table 7-6 of Appendix A of the Technical Support Document
(TSD),\59\ indicate that PM contributes less than 0.5% of the total
visibility impacts from Flint Creek Boiler No. 1 at all nearby Class I
areas with the exception of Upper Buffalo. PM contributions to
visibility impacts at Upper Buffalo from Flint Creek are less than 2%
of the total visibility impairment at this Class I area. On the most
impacted day at Upper Buffalo, modeling the 24-hr actual maximum
emissions demonstrates that PM contributes only 0.07 dv of the total
3.781 dv modeled visibility impact from the source. As stated in the
proposal, we found that the visibility impact from PM emissions alone
is so minimal such that the installation of any additional PM controls
on the unit (including any upgrades to the existing controls) could
only have minimal visibility benefit and therefore would not be
justified. This is in keeping with the BART Rule, which states the
following:
---------------------------------------------------------------------------

    \59\ These documents can be found in the docket for our
rulemaking.

    ``Consistent with the CAA and the implementing regulations,
States can adopt a more streamlined approach to making BART
determinations where appropriate. Although BART determinations are
based on the totality of circumstances in a given situation, such as
the distance of the source from a Class I area, the type and amount
of pollutant at issue, and the availability and cost of controls, it
is clear that in some situations, one or more factors will clearly
suggest an outcome. Thus, for example, a State need not undertake an
exhaustive analysis of a source's impact on visibility resulting
from relatively minor emissions of a pollutant where it is clear
that controls would be costly and any improvements in visibility
resulting from reductions in emissions of that pollutant would be
negligible. In a scenario, for example, where a source emits
thousands of tons of SO2 but less than one hundred tons
of NOX, the State could easily conclude that requiring
expensive controls to reduce NOX would not be
appropriate. In another situation, however, inexpensive
NOX controls might be available and a State might
reasonably conclude that NOX controls were justified as a
means to improve visibility despite the fact that the source emits
less than one hundred tons of the pollutant.'' \60\
---------------------------------------------------------------------------

    \60\ 70 FR 39116.

    Clearly, the most effective controls to address visibility
impairment from the source are those that would reduce emissions of
visibility impairing pollutants other than direct emissions of PM.
Therefore, we are finalizing our proposed disapproval of the
NOX and SO2 BART determinations for Flint Creek
Boiler No. 1, as ADEQ did not properly identify and evaluate
NOX and SO2 controls to address visibility
impairment from the source. As explained elsewhere in our response to
comments, this is consistent with the BART Guidelines and with our
action on other state's RH SIPs.
    Comment: The EPA's 2004 proposed RHR provided extensive technical
justification to establish that the presumptive limits represent cost
effective technologies equivalent to BART. In addition, the 2004
proposed RHR provides that the adoption of the presumptive limits by
the state is acceptable unless the states choose to conduct a BART
analysis to support different limits. Arkansas relied on the 2004
proposed RHR to adopt presumptive limits, along with consultation with
BART-eligible sources to determine whether any site-specific factors
vary significantly from those examined by EPA. Since no factors have
been identified by the affected sources, Arkansas adopted EPA's
presumptive limit without any further analysis. That is all that is
required under the RHR.
    Response: The EPA agrees that we went through extensive analysis to
provide presumptive BART emission limits. As stated in our proposed
rulemaking on the Arkansas RH SIP, the purpose of the presumptive
limits in the BART Guidelines was to identify controls that the Agency
considered to be generally cost-effective across all affected units.
Because EPA's extensive analysis found that these controls are
generally cost-effective across all affected units and were anticipated
to result in a substantial degree of visibility improvement, EPA
concluded that such units should at least meet the presumptive limits.
However, the RHR and the BART Guidelines make clear that the
presumptive limits are rebuttable.\61\ As discussed elsewhere in our
response to comments, the RHR and the BART Guidelines make clear that
the presumptive limits will not necessarily be the appropriate level of
control for all EGUs. Therefore, EPA cannot approve any BART
determination that relies upon the presumptive emission limit unless
the five factor BART analysis shows the presumptive emission limit
meets BART. EPA disagrees that the 2004 proposed RHR provides that the
adoption of the presumptive limits by the state is acceptable unless
the state chooses to conduct a BART analysis to support different
limits. The RHR (in some instances referred to in the comment as the
BART Rule) and the BART Guidelines do not provide that a state may
choose to conduct a BART analysis to support different limits. The RHR
states the following concerning presumptive limits:
---------------------------------------------------------------------------

    \61\ 71 FR 60619.
---------------------------------------------------------------------------

    ``If, upon examination of an individual EGU, a State determines
that a different emission limit is appropriate based upon its analysis
of the five factors, then the State may apply a more or less stringent
limit.'' \62\
---------------------------------------------------------------------------

    \62\ 70 FR 39132.
---------------------------------------------------------------------------

    There is similar language elsewhere in the RHR and the BART
Guidelines. The RHR and the BART Guidelines do not contain language
giving the State discretion to determine whether or not to conduct a
five factor BART analysis when the presumptive emission limits have
been adopted.
    The EPA disagrees that reliance on the 2004 proposed RHR to adopt
presumptive limits along with consultation with subject to BART sources
to determine whether any site-specific factors vary significantly from
those examined by EPA is all Arkansas is required to do to satisfy the
BART requirements under the RHR. The RHR states that for each source
subject to BART, states are required to identify BART after considering
the five statutory factors in CAA section 169A(g), as follows:

    ``States must identify the best system of continuous emission
control technology for each source subject to BART taking into
account 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
visibility improvement that may be expected from available control
technology.'' \63\
---------------------------------------------------------------------------

    \63\ 70 FR 39158.

    Therefore, adoption of the NOX and SO2
presumptive limits alone does not satisfy the requirements of the RHR
and the CAA.
    Comment: The EPA's 2004 proposed RHR supports the position that the
presumptive limits identified in the RHR are adequate to meet the
visibility requirements for the first implementation period of the RHR.
Thus, Arkansas's use of presumptive limits should be approved because,
like the RHR confirms, use of presumptive limits by Arkansas ensures
that there is sufficient visibility improvement to satisfy the URP
goals. The EPA's suggestion that a more detailed or extensive
investigation is required is not supported by the RHR or guidance. It
is the state's prerogative to make this determination and to choose
what sources of information and degree of investigation is adequate.
Having confirmed EPA's expectations, the state's submission should be
approved.
    Response: Neither the 2004 proposed nor the final RHR provide that