[Federal Register Volume 84, Number 90 (Thursday, May 9, 2019)]
[Rules and Regulations]
[Pages 20274-20292]
[FR Doc No: 2019-09478]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2017-0290; FRL-9993-36-Region 3]

Approval and Promulgation of Air Quality Implementation Plans;
Pennsylvania; Regulatory Amendments Addressing Reasonably Available
Control Technology Requirements Under the 1997 and 2008 8-Hour Ozone
National Ambient Air Quality Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is taking action on
a state implementation plan (SIP) revision submitted by the
Commonwealth of Pennsylvania (Pennsylvania). This revision consists of
regulatory amendments intended to meet certain reasonably available
control technology (RACT) requirements under the 1997 and 2008 8-hour
ozone national ambient air quality standards (NAAQS). EPA is approving
most parts of the Pennsylvania SIP revision as meeting RACT
requirements under the Clean Air Act (CAA), while conditionally
approving certain provisions, based upon Pennsylvania's commitment to
submit additional enforceable measures that meet RACT. This action is
being taken in accordance with the requirements of the CAA.

DATES: This final rule is effective on June 10, 2019. Pennsylvania must
meet the conditions of this approval by May 9, 2020.

ADDRESSES: EPA has established a docket for this action under Docket ID
Number EPA-R03-OAR-2017-0290. All documents in the docket are listed on
the https://www.regulations.gov website. Although listed in the index,
some information is not publicly available, e.g., confidential business
information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the internet and will be publicly available only in hard
copy form. Publicly available docket materials are available through
https://www.regulations.gov, or please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section for additional availability
information.

FOR FURTHER INFORMATION CONTACT: Mr. Joseph Schulingkamp, Planning and
Implementation Branch (3AD30), Air and Radiation Division, U.S.
Environmental Protection Agency, Region III, 1650 Arch Street,
Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-
2021. Mr. Schulingkamp can also be reached via electronic mail at or by
email at<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. Background

    On March 14, 2018 (83 FR 11155), EPA published a notice of proposed
rulemaking (NPRM) for a SIP revision from the Commonwealth of
Pennsylvania. In the NPRM, EPA proposed to partially conditionally
approve and partially approve a Pennsylvania RACT SIP revision for the
1997 and 2008 8-hour ozone NAAQS. The formal SIP revision was submitted
by the Pennsylvania Department of Environmental Protection (PADEP) on
May 16, 2016.
    RACT requirements apply to any ozone nonattainment areas classified
as Moderate or higher (Serious, Severe or Extreme) under CAA sections
182(b)(2) and 182(f). Section 184(b)(1)(B) of the CAA also applies RACT
to all areas located within ozone transport regions established
pursuant to section 184 of the CAA. The entire Commonwealth of
Pennsylvania is part of the Ozone Transport Region (OTR) established
under section 184 of the CAA and thus is subject statewide to the RACT
requirements of CAA sections 182(b)(2) and 182(f), pursuant to section
184(b). The May 16, 2016 SIP submittal intends to satisfy sections
182(b)(2)(C), 182(f), and 184 of the CAA for both the 1997 and 2008 8-
hour ozone NAAQS for all major nitrogen oxides (NOx) and volatile
organic compound (VOC) sources in Pennsylvania not subject to control
technique guidelines (CTG) (i.e., VOC non-CTG sources), except glass
melting furnaces, ethylene production plants, surface active agents
manufacturing, and mobile equipment repair and refinishing.

II. Summary of SIP Revision and EPA's Proposed Actions

    The May 16, 2016 Pennsylvania SIP revision includes the
Pennsylvania regulations in 25 Pa. Code sections 129.96-129.100 titled
``Additional RACT Requirements for Major Sources of NOx and VOCs'' (the
RACT II Rule) and amendments to 25 Pa. Code section 121.1, including
related definitions, to be incorporated into the Pennsylvania SIP.
These regulatory amendments were adopted by PADEP on April 23, 2016 and
effective on the same date upon publication in the Pennsylvania
Bulletin. The May 16, 2016 SIP revision was submitted to satisfy
certain CAA RACT requirements under both the 1997 and 2008 8-hour ozone
NAAQS for specific source categories.
    The RACT II Rule applies statewide to existing major NOX
and/or VOC sources

in Pennsylvania, except those subject to other Pennsylvania
regulations, as specified in 25 Pa. Code 129.96(a)-(b).\1\ The RACT II
Rule exempts all VOC source categories for which PADEP had adopted CTG
RACT regulations at the time the RACT II Rule was finalized, as well as
three non-CTG VOC source categories: (1) Ethylene production plants,
(2) surface active agents manufacturing, and (3) mobile equipment
repair and refinishing; and glass melting furnaces as major NOx
sources. In the NPRM, EPA proposed to find that the applicability
requirements of 25 Pa. Code section 129.96 are necessary to implement
the RACT requirements within the RACT II Rule.
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    \1\ In the context of the RACT II Rule, the terms ``major
NOX emitting facility'' and ``major VOC emitting
facility,'' as defined in 25 Pa Code section 121.1, are used to
refer to major stationary sources.
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    The RACT II Rule requirements apply to any emissions unit or
process at an affected major source having a potential to emit (PTE) of
1 ton per year (TPY) or more of NOX and/or VOC. In the
context of the rule, existing major sources are those already in
existence as of July 20, 2012 or any major sources installed or
modified after July 20, 2012, which became a major source before
January 1, 2017. The RACT II Rule establishes a compliance date of
January 1, 2017, as provided in paragraphs in 129.97(a) and
129.99(d)(4), with some exceptions.
    Section 129.97 of the RACT II Rule establishes NOX and
VOC emission limits or operational requirements on certain types of
emissions units in the affected major sources which Pennsylvania
presumes to meet RACT, thus referred to in the rule as presumptive
RACT.
    Affected emissions units include combustion units, process heaters,
combustion turbines, stationary internal combustion engines, cement
kilns, municipal waste combustors, and municipal solid waste landfills.
In the NPRM, EPA proposed to find that the presumptive requirements of
25 Pa. Code section 129.97 represent RACT for the NOX and
VOC source categories affected by these provisions.
    Affected major sources subject to the presumptive requirements of
25 Pa. Code section 129.97 that cannot comply with the applicable
presumptive NOX limits for any given emissions units, may
choose one of two alternative compliance options to establish RACT.
Such sources may either propose an alternative NOX emissions
limit based on averaging NOX emissions from multiple
sources, under 25 Pa. Code section 129.98, or else propose an
alternative source-specific emission NOX or VOC limit or
RACT requirement, under 25 Pa. Code section 129.99. In the NPRM, EPA
proposed to find that 25 Pa. Code section 129.98 is not sufficient to
address RACT for sources seeking averaging, without the specific
NOX averaging provisions for any affected sources being
submitted to EPA for SIP approval. Also, in the NPRM, EPA proposed to
find that 25 Pa. Code section 129.99 is not approvable by itself
without further information on specific sources, along with the source-
specific limits being submitted to EPA for SIP approval. By letter
dated September 22, 2017, PADEP committed to address the problems with
sections 129.98 and 129.99, as later identified in the NPRM, by
submitting any facility-specific terms and conditions regarding
emissions averaging to EPA as a source specific SIP revision and
submitting all source-specific RACT determinations under section 129.99
to EPA as SIP revisions within 12 months of EPA's final approval.
Therefore, EPA proposed to conditionally approve the provisions in 25
Pa. Code sections 129.98 and 129.99.
    25 Pa. Code section 129.100 of the RACT II Rule establishes
compliance demonstration and recordkeeping requirements for affected
sources. Specific monitoring and testing requirements are established
for sources complying with presumptive RACT requirements under section
129.97. Recordkeeping requirements are established under section
129.100(d) for any affected sources under the RACT II Rule. In the
NPRM, EPA proposed to find that the compliance demonstration
requirements of 25 Pa. Code section 129.100 are necessary to implement
the RACT requirements of section 129.97. Also, additional compliance
demonstration requirements for NOX averaging or source-
specific RACT alternative limits will be established by PADEP or the
local permitting agency on a source-specific basis, in accordance with
sections 129.98 and 129.99, respectively, and consistent with section
129.100.
    Any definitions related to the RACT II Rule are codified in 25 Pa.
Code section 121.1. The definitional changes in 25 Pa. Code section
121.1 are consistent with requirements in the RACT II Rule and thus we
proposed to approve under CAA section 110. EPA proposed that the
amended provisions in 25 Pa. Code section 121.1 and the adopted
provisions in 25 Pa. Code sections 129.96, 129.97, 129.100 of the RACT
II Rule are approvable, in accordance with requirements in CAA sections
110, 172, 182, and 184, and meet RACT for the affected major sources of
non-CTG VOC and major sources of NOX for both the 1997 and
2008 8-hour ozone NAAQS. EPA proposed conditional approval of 25 Pa.
Code sections 129.98 and 129.99 for the reasons stated in this section
and in the NPRM in more detail.

III. Public Comments and EPA's Reponses

    During the comment period, EPA received relevant comments from
eight separate entities: The Connecticut Department of Energy and
Environmental Protection (CTDEEP), Friends of Pennsylvania (FOP), GenOn
Energy, Inc. (GenOn), the Maryland Department of Environment (MDE), the
State of New Jersey Department of Environmental Protection (NJDEP), the
New York State Department of Environmental Conservation (NYDEC),
Olympus Power, LLC (Olympus Power), and Sierra Club (SC). EPA also
received twelve irrelevant or non-adverse comments from anonymous
sources which will not be addressed here. The relevant comments and
EPA's response are discussed in this section of this rulemaking action.

A. Presumptive RACT

    Comment 1: Several commenters argue that PADEP's presumptive limits
for certain source categories do not represent RACT. The commenters
state that more stringent NOX RACT limits have been adopted
by other states for coal-fired utility boilers, such as in New York and
Connecticut's rules. Commenters also suggest there are more stringent
limits adopted for combustion turbines and stationary internal
combustion turbines.
    Response 1: EPA disagrees with the commenters that PADEP's
presumptive NOX RACT limits are not adequate as RACT. In
making RACT determinations, EPA has encouraged states to rely on
current EPA guidance, including CTGs and Alternative Control Techniques
(ACTs), \2\ and any other information available at the time of
development of the RACT SIP. See 78 FR 34178 at 34192. States have the
discretion to adopt more stringent limits as RACT for similar sources
when considering what emissions reductions of NOX and VOC
are necessary for timely attainment of the ozone NAAQS (i.e., beyond
RACT reductions).
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    \2\ EPA uses CTGs to presumptively define VOC RACT while ACTs
describe available control technologies and their respective cost
effectiveness.
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    Based on existing EPA guidance, EPA determined that the RACT II
Rule's presumptive requirements generally represent emission
limitations

achievable through implementation of reasonably available control
technologies considering technical and economic feasibility. In
addition, EPA reviewed NOX emissions limits in effect in
adjacent OTR states for certain source categories addressed by
Pennsylvania's rule for comparison purposes. EPA concluded that PADEP's
presumptive limits are comparable to other states' limits, denoting
that while some states may have adopted more stringent limits for
similar categories, other states have also adopted less stringent
controls. However, nothing in the CAA requires Pennsylvania's RACT
limits to be as stringent as neighboring states' limits.
    Some states may have adopted more stringent controls for similar
source categories given needs for ozone reduction to achieve attainment
within their particular state or to go ``beyond RACT'' for the state's
internal reasons. For instance, it is also worth noting that
Connecticut's 22a-174-22e rule established NOX presumptive
limits that would become effective in two phases on June 1, 2018 for
2008 RACT requirements and June 1, 2022; and EPA only considered the
June 1, 2018 control requirements under this regulation to be adequate
and needed to meet 2008 ozone RACT.\3\ EPA continues to find that
Pennsylvania's presumptive NOX limits are reasonable for the
source categories evaluated for the reasons described in detail in our
NPRM and TSD. EPA's determination considered for each source category
the emission rates achieved by different NOX control
technologies as discussed in the guidance documents and summarized in
the TSD, and limits that other states have adopted to meet RACT.
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    \3\ See 82 FR 16776. In addition, EPA notes that Connecticut has
areas in more severe nonattainment with the ozone NAAQS than
Pennsylvania and as such may need more NOX reductions.
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    In addition, PADEP received similar comments from Connecticut and
New Jersey on its proposed RACT II Rule, asserting that each state had
adopted more stringent presumptive NOX limits for coal-fired
boilers than Pennsylvania. In its response, PADEP asserted that it
``reviewed and considered RACT regulations from various states when
evaluating what constitutes reasonably available control technology for
the types of sources affected by the final rulemaking.'' PADEP stated
that ``[s]ource categories in Pennsylvania are diverse, with numerous
sources having varying characteristics differing from those of the
other Mid-Atlantic States,'' and that it ``evaluated its source
categories and determined the presumptive RACT requirements to be
adequate.'' Further, after considering comments received, PADEP
determined that the NOX limits for coal-fired boilers with a
rated heat input equal to or greater than 250 million British Thermal
Units (MMBTU) per hour (MMBTU/hr) could be revised to reflect more
stringent RACT. PADEP revised the presumptive NOX limit from
coal-fired boilers that are circulating fluidized bed combustion units
(CFBs) from 0.20 pounds per MMBTU (lbs/MMBTU) to 0.16 lbs/MMBTU. PADEP
also adopted additional presumptive RACT requirements for coal-fired
boilers with selective non-catalytic reduction (SNCR) and selective
catalytic reduction (SCR), established in subparagraph
129.97(g)(1)(vii) and 129.97(g)(1)(viii). See PADEP's Response to
Comments Document, Comments #61 and #75.\4\ Thus, EPA believes that
PADEP considered and addressed technically and economically feasible
rates for RACT as well as considered rates established for RACT in
neighboring states in its development of the presumptive limits for the
RACT II Rule.
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    \4\ PADEP's Response to Comments Document is available in the
docket for this rulemaking action at www.regulations.gov, Docket
#EPA-R03-OAR-2017-0290, document #EPA-R03-OAR-2017-0290-0004
(hereafter referred to as Docket item #0004).
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    EPA recognizes that other states have adopted more stringent RACT
standards for source categories similar to those in Pennsylvania.
However, that fact alone is not sufficient to conclude that PADEP's
presumptive limits are not acceptable or reasonable as RACT. States
have the discretion to adopt more stringent limits as RACT for similar
sources when considering the emissions reductions of NOX and
VOC necessary for timely attainment of the ozone NAAQS, or to adopt
``beyond RACT'' limits for their own internal reasons. RACT
requirements for ozone do not require Pennsylvania to adopt the same
level of control as the most stringent state in the OTR or country;
what is instead required is emission limitations reflecting what is the
lowest achievable rate considering technological and economic
feasibility.\5\ Each state should set RACT limits considering what it
determines reasonable for its sources. In general, the actual cost,
emission reduction, and cost-effectiveness levels that an individual
source will experience in meeting the RACT requirements will vary from
unit to unit and from area to area. These factors will differ from unit
to unit because the sources themselves vary in age, condition, and
size, among other considerations and, in many cases, will differ from
state to state.\6\ EPA believes that PADEP determined presumptive
limits based on its evaluation of technical and economic feasibility of
controls and determination of what is reasonable for each source
category.\7\
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    \5\ See December 9, 1976 memorandum from Roger Strelow,
Assistant Administrator for Air and Waste Management, to Regional
Administrators, ``Guidance for Determining Acceptability of SIP
Regulations in Non-Attainment Areas,'' and also 44 FR 53762;
September 17, 1979.
    \6\ See EPA's March 16, 1994 Memorandum ``Cost-Effective
Nitrogen Oxides (NOX) Reasonably Available Control
Technology (RACT)''.
    \7\ See 46 PaB 2037.
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    Comment 2: One commenter argues that PADEP's presumptive limits for
municipal waste combustors (MWCs) do not represent RACT for several
reasons. The commenter argues that for mass burn waterwall type MWCs
using SNCR as a control, states have adopted more stringent
NOX limits of 150 parts per million by volume, dry basis
(ppmvd). Also, the commenter states that neither PADEP nor EPA
considered the NOX RACT limit of 150 ppmvd that was adopted
by NJDEP. The commenter argues that Pennsylvania should have
established NOX presumptive limits for MWCs for each type of
combustor technology, which is how states and EPA typically regulate
MWCs considering that NOX emissions vary by each technology.
    Response 2: EPA disagrees with commenter's assertion that PADEP's
presumptive NOX RACT limit of 180 ppmvd for MWC is not
adequate as RACT. PADEP's NOx presumptive limit of 180 ppmvd at 7
percent (%) oxygen (O2) for MWC is reasonable as RACT, based
on NOX emission rates established by other states'
regulations and in EPA's New Source Performance Standards (NSPS) at 40
CFR part 60, subparts Cb and Eb. In the NSPS, EPA has established
NOX limits for MWCs ranging from 150 to 250 ppmvd at 7%
O2 after considering the best system of emissions reduction
(BSER). Also, as noted in the TSD, OTR states have adopted
NOX limits for MWCs ranging from 120 to 372 ppmvd at 7%
O2, with different averaging periods. PADEP's presumptive
RACT limit for MWCs is comparable to EPA's most stringent
NOX limit for MWCs in the NSPS and is comparable to the most
stringent limits adopted by other states given that factual scenarios
regarding technical and economic feasibility for controls for MWCs can
vary amongst states. EPA has no reason to believe that Pennsylvania did
not consider the existing controls at the MWCs, such as SNCR, when
determining RACT. For large MWCs with SNCR, other states have
established average daily NOX limits as

high as 250 ppmvd; thus, Pennsylvania's limit of 180 ppmvd is more
stringent for sources with SNCR than some states. Finally, EPA does not
believe that MWCs must be exclusively regulated by type of combustor.
In EPA's MWC regulations for NOX emission limits, EPA set
limits according to the type of combustor and also set a single
NOX limit that applies regardless of combustor type. See 40
CFR part 60, subparts Cb and Eb.
    In determining RACT, states should also consider any information
received during the public comments. EPA reviewed the comments received
by PADEP during the state's public comment period on the RACT II Rule.
PADEP initially proposed that MWCs meet RACT by complying with the
limits EPA established in the NSPS at 40 CFR part 60, subpart Cb or
Subpart Eb, which range from 180 to 250 ppmvd at 7% O2. In
response to comments, PADEP re-evaluated NOX emissions data
from its MWCs and concluded that a NOX emission limit of 180
ppmvd at 7% O2, the lowest limit in the NSPS, was more
representative of actual emissions achieved across the fleet of MWCs in
Pennsylvania, and therefore revised the final rule to adopt this
NOX limit as presumptive RACT. See PADEP's Response to
Comments Document, Docket item #0004, Comments #121. Thus, EPA believes
Pennsylvania considered for MWCs technical and economic feasibility in
setting lowest achievable emission rate for MWCs by considering what
was achieved by MWCs within the Commonwealth and thus EPA finds the
presumptive RACT rate reasonable.
    Finally, while EPA recognizes that other states have adopted more
stringent RACT standards for MWCs, that fact alone is not sufficient to
conclude that PADEP's presumptive limits are not acceptable or
reasonable as RACT as previously discussed. States have the discretion
to adopt more stringent limits as RACT for similar sources considering
the level of emissions reductions of NOX and VOC necessary
to timely attain the ozone NAAQS (i.e., beyond RACT reductions).
Requiring Pennsylvania to adopt the same level of control as the most
stringent state is not always necessary to satisfy the statutory
mandate for RACT. EPA continues to find that Pennsylvania's presumptive
NOX limit for MWCs is reasonable and represents RACT.
    Comment 3: Several commenters state that coal-fired boilers with
SCR in Pennsylvania are capable of achieving lower rates than 0.12 lbs/
MMBTU. One commenter recommends that EPA disapprove the presumptive
limit for coal-fired boilers with SCR and impose a limit of 0.09 lbs/
MMBTU, while another commenter proposes a limit of 0.07 lbs/MMBTU. Both
commenters reference NOX actual emissions data included as
part of the comments and assert that NOX emission rates
lower than 0.12 lbs/MMBTU have been historically achieved by units in
Pennsylvania. One commenter included NOX emissions data that
represents the ``best performing ozone season emissions rate'' (in lbs/
MMBTU) for 13 coal-fired boilers in Pennsylvania equipped with SCR
during 2005 to 2017. The second commenter provided NOX
emissions data for monthly average NOX rates lower than
0.017 lbs/MMBTU during 2005 to 2017 for 10 coal-fired boilers in
Pennsylvania equipped with SCR.
    Response 3: EPA disagrees that a more stringent NOX RACT
limit than 0.12 lbs/MMBTU is needed for Pennsylvania to meet RACT for
coal-fired boilers with SCR, based on the data provided and absent any
other technical justification to support a more stringent limit. The
NOX emissions data sets provided by the commenter are not
sufficient to conclude that a lower NOX emissions rate, such
as 0.07 or 0.09 lbs/MMBTU, is consistently achievable or sustainable to
make Pennsylvania's conclusions unreasonable. RACT involves an
evaluation of what is technically and economically feasible for
sources; thus, consideration of whether emission limits are
consistently achievable with controls that are cost effective and under
consideration is a reasonable consideration for Pennsylvania. EPA
acknowledges that historically, some individual coal-fired electric
generating units (EGUs) with SCR in Pennsylvania have been able to
achieve lower rates than 0.12 lbs/MMBTU as indicated in the commenters'
data. However, in evaluating fleet-wide NOX emissions and
determining an adequate achievable NOX RACT emissions limit
for all units in Pennsylvania, the lowest historical rate at any
particular unit at a specific point in time may not be a rate that can
be consistently achieved by other units. EPA does not require RACT
limits to be the lowest achievable emissions rate, but the lowest
achievable emission rates considering technical and economical
limitations.
    In previous RACT guidance to states, EPA estimated that coal-fired
boilers with SCR are expected to generate NOX emissions
rates ranging from 0.10 to 0.25 lbs/MMBTU, depending on the type of
boiler and whether the boiler is equipped or not with additional
combustion controls.\8\ Also, as part of the 2016 Cross-State Air
Pollution Rule (CSAPR) Update, EPA determined that 0.10 lbs/MMBTU is an
achievable NOX emissions rate during ozone season for coal-
fired electric generating units (EGUs) with SCR.\9\ As part of the
CSAPR Update, EPA analyzed NOX reduction potential and
corresponding NOX ozone season emissions budgets at utility
boilers (i.e., EGUs) based on NOX emissions rates that can
be consistently achieved for the units with SCRs that were not
currently being optimized or which were currently idled at the time of
EPA's analysis (i.e., 2016). To determine the NOX emissions
rate that could be consistently achieved, EPA evaluated coal-fired
NOX ozone season emission data for EGUs from 2009 through
2015 and calculated an average NOX ozone season emissions
rate across the fleet of coal-fired EGUs with SCR for each of these
seven years. The 0.1 rate represents the third lowest fleet-wide
average coal-fired EGU NOX ozone season emissions rate for
coal-fired EGUs with SCR. It is worth noting that EPA considered and
rejected the lowest or second lowest ozone season NOX rates,
because it determined that these rates may reflect new SCR systems and/
or existing SCR systems with all new components (e.g., due to
simultaneous replacement of multiple layers of catalyst rather than
routine replacement of a single layer).\10\ Therefore, reliance alone
on the lowest historical emissions rate to evaluate the feasibility and
cost effectiveness of controls would likely overestimate the emissions
reductions and, consequently, underestimate the costs to restart idled
or unoptimized controls because some EGUs have significantly curtailed
their hours of operation, for various reasons, since the time when the
low levels of NOX emissions were achieved. Furthermore, SCR
controls can become less effective at NOX removal as they
age and may not be as efficient as when first installed, so the lowest
historically achieved rate is not always technically feasible. It is
not unreasonable for Pennsylvania to have considered a slightly
different NOX

emission rate for RACT considering such technological and economic
feasibility issues than what EPA has deemed achievable as an ozone
season-only NOX rate (0.10 lbs/MMBTU), when averaging over a
shorter time period such as 30 days.
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    \8\ EPA's ACT Document ``NOX Emissions Document
``NOX Emissions from Utility Boilers'' (EPA-453/R-94-023;
March 1994). It is possible that further technological advancements
may have been proven to result in lower NOX emissions
levels than those reported in EPA's ACT.
    \9\ See 81 FR 74504, 74543 (October 26, 2016) (addressing
interstate transport of ozone for 2008 ozone NAAQS).
    \10\ Data from these new systems are not representative of
ongoing achievable NOX rates considering that some SCR
systems may have some broken-in components and routine maintenance
schedules entailing replacement of individual components.
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    Even when considering lowest achievable rates, the data sets
provided by the commenters are not sufficient to support the assertion
that a NOX rate of 0.07 or 0.09 lbs/MMBTU, respectively, or
in fact any other rate lower than 0.12 lbs/MMBTU, is consistently
achievable in Pennsylvania. The first commenter, the Sierra Club, only
considered data for the limited instances where the lowest
NOX rates have been achieved and did not consider any other
periods during the 2003 to 2012 timeframe.\11\ For example, in Table 2
of Sierra Club's comments, the commenter presented the data from
multiple units at multiple facilities on a monthly basis. The commenter
then appeared to sort the data in terms of average NOX rate
from the lowest rate to the highest rate but limited the data to those
units and months where the average NOX rate was less than or
equal to 0.07 lbs/MMBTU. By doing this, the commenter does not take
into account the months where a unit is operating at a rate above 0.07
lbs/MMBTU skewing the data in a way that tends to show these units are
able to comply with a lower emissions limit at all times. Furthermore,
by sorting the data in this way, the commenter obscures important
information such as which facilities and units were evaluated, and the
range of years or months evaluated; thus, the incomplete data set
submitted by the commenter was not sufficient for EPA to determine that
Pennsylvania's RACT is not permissibly or reasonably set at 0.12 lb/
MMBtu.
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    \11\ See Tables 2 and 3 of Sierra Club's comments, dated April
13, 2018.
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    The second commenter, the MDE, provided the best performing ozone
season NOX emissions rates during 2005 to 2017, but only
considered emissions rates of certain facilities and certain units that
were specifically lower than 0.09 lbs/MMBTU. The NOX rates
provided by the commenter were ozone season averages, not 30-day
rolling averages. PADEP's coal-fired emission limit of 0.12 lbs/MMBTU
is required on a 30-day rolling basis and is applicable on a continuous
basis throughout the year (not just during ozone season). Therefore,
the data provided by MDE is not comparable to the form of
Pennsylvania's RACT emission limitation.
    Finally, states must establish presumptive NOX emission
limits for RACT that are reasonably achievable for the entire fleet of
units within any source category. Both commenters only included data
below certain thresholds, so only some of the data from these units was
shown, making it hard to judge the overall representativeness of the
data. In its SIP revision, PADEP confirmed that the presumptive RACT
NOX limits for coal-fired boilers ``are achievable and
sustainable during the expected life of the affected unit using
technologies that are both technically and economically feasible.''
\12\ Absent any conflicting technical information, EPA continues to
believe that a NOX emissions rate of 0.12 lbs/MMBTU on a 30-
day rolling average, year-round, is reasonable and consistently
achievable by Pennsylvania's coal-fired boilers with SCR,
representative of SCR operation, and adequate for representing RACT for
these units based on Pennsylvania's analysis.
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    \12\ See PADEP's Response to Comments Document, Docket item
#0004, Comment #10, Page 23.
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    Comment 4: One commenter contends that EPA cannot approve the
provision in 25 Pa Code section 129.97(g)(1)(viii) applicable to coal-
fired boilers with SCR, because there is no adequate basis for the
minimum SCR operating temperature and the minimum operating temperature
of 600 [deg]F is contradicted by facts concerning SCR operation and
inlet temperature. The commenter argues that neither EPA nor
Pennsylvania have justified that a temperature-based exemption is
necessary or that 600 [deg]F is the correct threshold for such
exception. The commenter states that EPA did not mention this
``loophole'' in its proposal. The commenter also argues that EPA's
allowance of a temperature exemption is in direct contrast to prior
actions by EPA, in which EPA recognized that a minimum SCR operating
temperature varies significantly between EGUs and required utilities to
supply more technical data to support any accommodation of this
parameter. See 81 FR 21735 (April 13, 2016).
    Response 4: EPA recognizes that neither Pennsylvania nor EPA
explained in detail why the minimum SCR temperature exemption in
127.97(g)(1)(viii) for coal-fired boilers is adequate for RACT.
However, EPA disagrees that our determination to accept this exemption
as part of Pennsylvania's presumptive limits for coal-fired combustion
units is arbitrary or capricious. As proposed in the NPRM, EPA finds
that Pennsylvania's determination to limit the application of the SCR
limit when inlet temperature is less than 600 [deg]F is consistent with
the optimum operating temperature of SCRs used generally by coal-fired
boilers and reasonable as part of the presumptive RACT limitation. The
temperature at the inlet to the SCR provides a good indication of
catalytic reduction performance, because it indicates that the gas
stream is at sufficient temperature to initiate reduction of
NOX on the catalyst. EPA finds that the NOX
reduction reaction of an SCR is effective only within a given
temperature range. If the inlet temperature (i.e., of the process gas
stream) is too high, it may cause NOX generation in the SCR
rather than NOX reductions. (Reference: https://www3.epa.gov/ttnchie1/mkb/documents/B_15a.pdf). The use of a catalyst
in the SCR process lowers the temperature range required to maximize
the NOX reduction reaction. At temperatures below the
specified range, the reaction kinetics decrease, and ammonia passes
through the SCR (ammonia slip), but there is little effect on nitrous
oxide (N2O) formation. At temperatures above the specified
range, nitrous oxide (N2O) formation increases and catalyst
sintering and deactivation occurs, but little ammonia slip occurs. It
has been proven that for the majority of commercial catalysts (metal
oxides), the typical operating temperatures for the SCR process range
from 480 [deg]F to 800 [deg]F (250-430 [deg]C). The rate of
NOX removal increases with temperature up to a maximum
between 700 [deg]F and 750 [deg]F (370-400 [deg]C). (Reference: https://www.epa.gov/sites/production/files/2017-12/documents/scrcostmanualchapter7thedition_2016revisions2017.pdf; see Reference
[46].)
    In addition, EPA noted in its response to comments on the May 2016
updates to the Cost Control Manual for the SCR chapter that, while the
temperature of 480 [deg] to 800 [deg]F is a fairly wide range and is
dependent on catalyst type, this range is not reflective of general
optimum range. EPA concluded that 480 [deg] to 800 [deg]F is an
``operating'' range and that 700 [deg] to 750 [deg]F was an optimum
temperature range.\13\ It has been proven that the NOX
removal efficiency decreases more drastically when temperatures are
lower than the optimal operating range; at 600 [deg]F, the expected
NOX removal efficiency of an SCR has already decreased to
77% and at 550 [deg]F the removal efficiency drops to 63%. Therefore,
even if Pennsylvania were to lower the

temperature at which a SCR was to begin operating by 50 [deg]F, the
reductions achieved would be only slightly better than those achieved
with Low NOX burners with Overfired Air (40-60% reduction)
which is already required to be installed by the existing Pennsylvania
SIP. Thus, EPA finds Pennsylvania's selection of 600 [deg]F requirement
for coal-fired boiler RACT reasonable based on noted efficiencies with
SCRs at such temperatures and based on technical and economic
considerations from use of additional catalyst to achieve diminishing
NOX removal.
---------------------------------------------------------------------------

    \13\ See EPA, Air Pollution Cost Control Manual, Section 4--
NOX Controls, Chapter 2 at section 2.2.2. May 2016,
updated November 2017.
---------------------------------------------------------------------------

    In the NPRM, EPA recognized that the SCR limit is not applicable at
all times, given the temperature condition provided. Nevertheless, EPA
disagrees that this qualifies as a ``loophole'' of the regulation. As
discussed in the TSD in support of our proposed action, any affected
boiler with SCR or SNCR is also required to comply at all times with
the boiler type limits in section 129.97(g)(1)(vi), which in practice
would be applicable in any instances where the SCR or SNCR is not in
operation. For instance, a coal-fired boiler that has an SCR in place
would be subject in practice to two sets of RACT NOX limits:
(1) The SCR limit of 0.12 lbs/MMBTU when the inlet temperature to the
control is equal to or greater than 600 [deg]F; and (2) the boiler type
limit (0.16, 0.35, or 0.40 lbs/MMBTU depending on type of boiler) at
any other times when the inlet temperature to the control is less than
600 [deg]F. EPA finds that this control approach is practical and
acceptable to satisfy RACT for boilers with SCR and SNCR, as it ensures
applicability of RACT year-round, while requiring the lowest
NOX emissions limit considering the technical feasibility of
existing NOX controls. As stated in our TSD for the NPRM, in
our engineering judgment and based upon acknowledged technical
limitations of SCR and SNCR, EPA agrees with PADEP's determination that
SCR or SNCR cannot result in lower NOX emission rates at
those lower operating temperatures. See page 21 of the TSD.
    Comment 5: The commenter claims that section 129.97(g)(1)(viii) of
the RACT II Rule has allowed Pennsylvania utilities since 2017 to use
the minimum temperature-exemption for coal-fired boilers with SCR to
intentionally avoid operating controls at night. The commenter provides
NOX emissions and heat input rating from one particular EGU
coal-fired boiler, Cheswick, and alleges that it depicts a typical
practice and typical emission rate from the coal-fired EGU boilers with
SCR in Pennsylvania subject to the RACT II Rule.
    Response 5: As discussed in the prior response, the RACT II Rule's
temperature exception in section 129.97(g)(1)(viii) does not allow
coal-fired boilers equipped with SCR to avoid all NOX
controls. Although any coal-fired boiler with SCR is not subject to the
0.12 lbs/MMBTU RACT emission limitation when inlet temperature is below
600 [deg]F, these boilers must still comply at all times with the
presumptive limits in section 129.97(g)(1)(vi), which vary based upon
the furnace configuration or boiler type.
    The Cheswick unit is a tangentially coal-fired boiler equipped with
low NOX burners (LNB) with separated overfire air (SOFA) and
SCR. As such, the unit is required to comply with two presumptive
NOX limits under the RACT II Rule: 0.12 lbs/MMBTU when inlet
temperature to the SCR is above 600 [deg]F, and 0.35 lbs/MMBTU at all
other times. See section 129.97(g)(1)(vii) and (vi)(B). EPA notes that
a reduction of heat input at night for Cheswick is not unusual for a
coal-fired EGU boiler as the reduction in heat input can be driven by
lower demand for electricity; thus reduced heat input could lead to
temperatures below 600 [deg]F and below what is optimal for SCR
operation.
    Comment 6: One commenter claims Pennsylvania's rule does not
require a reporting requirement for the exhaust temperature of units
equipped with SCR, and that without this information the public will
not be able to know whether or not such units are complying with the
applicable emission limits. The commenter claims the lack of this
reporting requirement renders calculating compliance with the 30-day
average difficult and, overall, violates the CAA's requirement that
RACT be enforceable.
    Response 6: EPA disagrees with the commenter. Although PADEP's RACT
II Rule does not establish RACT-specific reporting requirements for
each source category, Pennsylvania has the generic recordkeeping
requirements at section 129.100(d) requiring that a source subject to
sections 129.96-129.99 ``keep records to demonstrate compliance with
Sec.  Sec.  129.96-129.99 that include sufficient data and calculations
to demonstrate that the requirements of Sec. Sec.  129.96-129.99 are
met.'' See 25 Pa Code 129.100(d). EPA finds that the compliance
demonstration requirements of 129.100(d) require sources to keep
sufficient records to demonstrate meeting RACT limits. PADEP may
establish more specific requirements for individual sources, as needed,
through the operating permit process.
    Comment 7: One commenter argues that EPA should disapprove the PA
RACT II Rule's provision in section 129.97(g)(1)(ix) concerning coal-
fired boilers with SNCR, based on the inadequate information provided
as part of the ``illegal and improperly submitted'' supplemental
documentation. The commenter asserts that PADEP's supplemental
documentation does not justify why PADEP did not impose an emission
limitation for coal-fired boilers in Pennsylvania, but simply
identifies the six Circulating Fluidized Bed (CFB) boilers with SNCR in
Pennsylvania subject to this requirement. Commenter asserts that in an
attempt to support that the 0.16 lbs/MMBTU presumptive limit for any
coal-fired CFB boiler is also adequate for coal-fired boilers with
SNCR, PADEP argues that CFB boilers without SCR have been able to
achieve lower NOX emission reductions than CFBs with SNCR.
Commenter also points to several EPA guidance documents supporting that
additional reductions can be achieved at EGU boilers through operation
of SNCR.
    Response 7: EPA disagrees with the commenter regarding the RACT
emission limitation for coal-fired boilers with SNCR. As explained in
the NPRM and TSD, such boilers are subject to emission limitations
(including a numeric limitation and a requirement to operate SNCR) that
Pennsylvania set considering technical and economic feasibility. Thus,
EPA finds these emission limitations reasonable as explained in more
detail in the NPRM and TSD. Sufficient information is available to
support this conclusion--all coal-fired boilers with SNCR are required
to comply with both the numeric emission limitations of section
129.97(g)(1)(vi) and the work practice standard under 129.97(g)(1)(ix).
In addition, Pennsylvania considered limits from other states and the
current limits in place at these sources. Furthermore, EPA does not
agree that the supplemental September 2017 submittal from PADEP is
illegal or was improperly submitted. PADEP's September 26, 2017
submittal included Pennsylvania's commitment to submit any facility-
wide or system-wide NOX averaging plans to EPA for SIP
approval and to submit to EPA for SIP approval any permits issued under
section 129.99 to support the conditional approval of 129.98 and 129.99
for the SIP. This commitment in Pennsylvania's supplement meets
requirements for a commitment under CAA section 110(k)(4). The
commenter has not provided sufficient information as to

why Pennsylvania's supplemental information is ``illegal.'' See
Response to Comment #34. Nevertheless, EPA has sufficient information
in the TSD and in the docket generally to support our conclusion that
Pennsylvania's RACT II Rule is reasonable including the RACT limitation
for coal-fired boilers with SNCR as the Rule includes a work practice
requirement as an emission limitation (as the Rule requires operation
of the SNCR) as well as a numeric restriction on emissions as an
emission limitation in section 129.97(g)(1)(vi). See also Response to
Comment #8.
    Comment 8: Commenters allege that EPA cannot approve the
presumptive provision contained in 129.97(g)(1)(ix) for coal-fired
boilers with SNCR because the provision lacks a numeric emission limit.
One commenter added the rule also failed to have a requirement to
optimize the existing SNCR control. Another commenter argued that
Pennsylvania should have been able to set a numeric emission limit
because such limits exist for other similar units with SNCR in place
and a numeric emission limit is required to meet EPA's definition of
``RACT.''
    Response 8: RACT generally requires the establishment of ``emission
limitations.'' Since the 1970's, EPA has consistently defined ``RACT''
as the lowest emission limit that a particular source is capable of
meeting by the application of the control technology that is reasonably
available considering technological and economic feasibility.\14\
However, EPA disagrees that an emission limitation is required to be
numeric to meet RACT for all source categories. CAA section 302(k)
defines an emissions limitation as ``a requirement established by the
State or the Administrator which limits the quantity, rate, or
concentration of emissions of air pollutants on a continuous basis
including any requirement relating to the operation or maintenance of a
source to assure continuous emission reduction, and any design,
equipment, work practice or operational standard promulgated under this
chapter.'' The requirement of 25 Pa. Code 129.97(g)(1)(ix), to operate
the system (i.e., coal-fired boilers with SNCR) with the injection of
reagents, qualifies as a work practice standard or an operational
requirement; thus, the provision meets the definition of ``emission
limitation'' under CAA section 307. Thus, Pennsylvania has established
a RACT emission limitation for coal-fired boilers with SNCR. In
addition, these boilers are also subject to boiler type presumptive
RACT limits (0.16, 0.35, 0.40, or 0.45 lbs/MMBTU) in 129.97(g)(v) and
(vi). Thus, coal-fired units are subject to both numerical limits and
work practice standards which reasonably establish RACT as an
``emission limitation'' considering technical and economic feasibility.
EPA also disagrees with the commenter's assertion that EPA should
require language to ensure optimum operation of SNCR controls because
this is not required for RACT-level control. EGUs are required to
optimize emission control for NOx (including SCR and SNCR) for
interstate ozone transport requirements for the 2008 ozone NAAQS. See
83 FR 50444 (October 5, 2018) (Response to Clean Air Act Section 126(b)
Petitions from Delaware and Maryland) (stating EGU sources would have
already optimized emission controls like SCR and SNCR when EPA
finalized the CSAPR Update in 2016 to address interstate transport of
ozone (81 FR 745504 (October 26, 2016)).
---------------------------------------------------------------------------

    \14\ See December 9, 1976 memorandum from Roger Strelow,
Assistant Administrator for Air and Waste Management, to Regional
Administrators, ``Guidance for Determining Acceptability of SIP
Regulations in Non-Attainment Areas,'' and also 44 FR 53762;
September 17, 1979.
---------------------------------------------------------------------------

B. NOX Averaging

    Comment 9: The commenter asserts that Pennsylvania's NOX
averaging formula in section 129.98(e) does not adequately set an
alternative emissions limit, as required by this provision in 129.98.
The commenter argues that the allowable NOX mass emissions
defined by the formula (Eiallowable) in 129.98 should be
``fixed,'' rather than changing with operating scenarios. The commenter
further requests that EPA disapprove section 129.98 because this
formula is unenforceable due to the unspecified method of calculation,
and because PADEP's interpretation of these provisions provided as part
of the supplemental document is clearly different from the plain
language of the rule.
    Response 9: As discussed in the NPRM and TSD, EPA identified
deficiencies in the NOX averaging provisions of the RACT II
Rule including the need for enforceable conditions. As previously
discussed, Pennsylvania committed in the September 26, 2017 letter ``.
. . to submit the terms and conditions dealing with emission averaging
to EPA as facility specific SIP revisions to address EPA's concerns.''
September 26, 2017 submittal, p. 2. EPA is conditionally approving
129.98 under CAA 110(k) based on this commitment. Thus, EPA agrees to a
limited extent with the comment regarding whether 129.98 adequately
established how to compute the alternative NOX limit. The
submission of alternative NOX limits and relevant compliance
demonstration requirements for approval into the SIP would allow EPA to
determine if each NOX averaging plan and underlying
alternative NOX limit is adequate for RACT. In addition, any
alternative limits provided by PADEP would need to be enforceable to
obtain EPA approval into the SIP.
    EPA does not agree with commenter that for the alternative
NOX emissions limit to be adequate and/or enforceable, it
must necessarily be a ``fixed'' limit. EPA has, in the past, approved
emission limitations based on equations where certain variables within
the equation change based on various aspects, such as type of fuel
being used, operating modes, or other specific
conditions.15 16 EPA believes that, as long as all possible
variables to be used are properly identified and the equation is
sufficiently constrained, the equation can be used to establish an
alternative emission limit and that limit can be enforceable.
---------------------------------------------------------------------------

    \15\ See Air Plan Approval; Georgia; Miscellaneous Revisions,
July 28, 2017 (82 FR 35106); specifically, Rule 391-3-1-.02(2)(e)
which establishes allowable particulate matter emission limits for
sources based on process input weight.
    \16\ See Approval and Promulgation of Air Quality Implementation
Plans; Montana; Regional Haze Federal Implementation Plan, September
12, 2017 (82 FR 42738); specifically, the best available retrofit
technology (BART) particulate matter emission rate for the Trident
cement kiln which is based on the concentration of particulate
matter, volumetric flow rate of the effluent gas, and total kiln
clinker production.
---------------------------------------------------------------------------

    Regarding the comment that Pennsylvania's interpretation of the
enforceability of averaging provisions in 129.98 is somehow different
in the September 2017 letter to EPA than what is in the terms of 25 Pa.
Code 129.98, EPA has addressed the enforceability issues relating to
averaging in 129.98 through the conditional approval and through
Pennsylvania's commitment to submit all such plans to EPA for SIP
approval. Pennsylvania's interpretation in the September 2017 letter
regarding terms in 129.98 is not germane as EPA is conditionally
approving 129.98 based on Pennsylvania's commitment to submit averaging
plans to EPA for SIP approval in response to EPA's identified
deficiencies in the NPRM regarding averaging.
    Comment 10: The commenter identified various concerns with the
equation provided in section 129.98(e) to estimate an alternative limit
for NOX emissions averaging. First, the commenter argues
that the equation is unenforceable because it does not properly explain
how to calculate

allowable NOX mass emissions for each affected emission
unit. The commenter also indicates that if PADEP allows the use of
actual heat input to calculate both actual NOX emissions
(Eiactual) and allowable NOX emissions
(Eiallowable), the source will never be found in violation
of the NOX averaging plan, as mathematically both sides of
the equation would increase proportionally.
    Response 10: EPA agrees with the commenter to the extent that EPA
already identified concerns with the equation provided in 129.98(e)
given its lack of specificity. These concerns led to our conditionally
approving 129.98 based upon Pennsylvania's commitment to submit to EPA
for inclusion in the SIP permits which will employ these NOX
averaging provisions. In order for section 129.98 to become fully
approved, PADEP must provide to EPA for approval into the SIP the
alternative emission limits adopted under section 129.98 and related
compliance demonstration requirements.
    EPA does not have sufficient information to assess if actual heat
input will in fact be used in calculating both actual and allowable
NOX emissions. Eiactual is defined in section
129.98(e) as ``the actual NOx mass emissions, including emissions
during start-ups, shutdowns and malfunctions, for air contamination
source i on a 30-day rolling basis.'' (italics added).
Eiactual cannot represent the ``actual NOx mass emissions''
if the actual heat input is not used in the calculation, so using
allowable heat input in calculating actual emissions would be
illogical. EPA also believes that PADEP intends to use actual heat
inputs when calculating Eiallowable, along with the
presumptive RACT emission rate (or more stringent emission rate
applicable to the source). PADEP's September 26, 2017 commitment
submittal states that ``[t]he allowable mass emissions are calculated
each hour using the presumptive NOx RACT emission limit (or more-
stringent limit, if applicable) and the actual heat input from the
Department certified CEMS.'' P. 1 (italics added). However, the RACT
regulations do not expressly specify whether actual heat input or
allowable heat input will be used in calculating
Eiallowable. This is one of several identified concerns
which led to EPA's conditional approval of section 129.98, and
Pennsylvania's commitment to submit NOX averaging plans for
approval into the SIP, with each plan including an enforceable
alternative emissions limit and compliance demonstration requirements.
    Comment 11: One commenter requests EPA require that NOX
averaging emissions limitations established under 25 Pa. Code section
129.98(e) be based on emissions rates (lbs/MMBTU), instead of mass
emissions (lbs).
    Response 11: EPA disagrees with commenter's request because there
is no requirement in the CAA that RACT emission limitations for
NOX averaging be based on emissions rates, as opposed to
NOX mass emissions. Although EPA allows the use of
NOX averaging to meet RACT for NOX sources, no
specific additional regulatory requirements concerning how to implement
a NOX averaging scheme were adopted by EPA. Therefore, EPA
believes that PADEP should have flexibility in choosing how to express
the NOX averaging limits, as long as PADEP can demonstrate
that the same level of RACT emission reductions will be achieved.\17\
---------------------------------------------------------------------------

    \17\ See 80 FR 12279.
---------------------------------------------------------------------------

    Comment 12: The commenter asserts that the system-wide and
facility-wide averaging equations do not set an ``alternative
limitation,'' which commenter claims is required by the plain language
of the RACT II Rule. Commenter asserts that the Rule requires
facilities to ``calculate the alternative facility-wide or system-wide
NOX RACT emission limit . . . .'' Commenter further states
that only the equation in 129.98(e) characterizes averaging as a method
for demonstrating compliance, while this is not the plain reading of
the remainder of section 129.98.
    Response 12: Because the Commenter did not cite to the particular
section or sentence of the RACT II Rule which is being interpreted or
quoted, EPA can only use its best judgment to surmise that the language
in section 129.98(e) is the source of the quoted language. Section
129.98(e) states ``[t]he owner or operator shall calculate the
alternative facility-wide or system-wide NOX RACT emissions
limitation using a 30-day rolling average for the air contamination
sources included in the application for the operating permit or plan
approval, . . . .'' There is no other language in section 129.98 which
is similar to the Commenter's quote. EPA believes that the term
``emission limitation'' in section 129.98(e) should be interpreted as
``Eiallowable,'' and that the calculation of
Eiallowable results in a total NOX mass emission
limitation for all of the sources included in the averaging plan, while
commenter is expecting the averaging plan to have an overall emission
rate limit, expressed as lbs NOX/million Btu heat input, for
the sources. When section 128.98(e) is considered in its entirety,
rather than considering just a portion of one sentence, there is no
conflict between the equations in 129.98(e) and the language of Section
129.98 overall. As discussed in the March 14, 2018 NPRM, EPA proposed
to conditionally approve the NOX averaging provisions in
section 129.98 given concerns about the specificity of the equation in
129.98(e) and the compliance demonstration requirements within the
rule. In this action, EPA is finalizing that conditional approval based
on Pennsylvania's commitment to submit permits with NOX
averaging to EPA for SIP approval. Section 129.98(e) states that an
alternative limit calculated by the owner or operator must be in the
operating permit modification or plan approval, and section 129.98(g)
requires that the application for such an averaging plan should
contain, ``. . . methods for demonstrating compliance. . . .'' The SIP
submittal should therefore address the emission limitation and the
compliance demonstration issues.
    Comment 13: One commenter states that an averaging plan is a method
of demonstrating compliance with presumptive NOX limits in
section 129.97, allowing sources to demonstrate compliance as a group
of emissions sources rather than as individual emissions sources.
    Response 13: EPA agrees that sources can use section 129.98 to
apply for an averaging plan covering multiple units or sources.
However, EPA does not agree that the averaging plan or equation in
section 129.98 will directly show compliance with the presumptive RACT
limits applicable to each source in the plan. The averaging plan or
equation in section 129.98 is instead intended to demonstrate that the
resulting NOX emissions using a 30-day rolling average would
not be greater than NOX emissions from the group of included
sources if they each complied with the applicable presumptive
NOX RACT emissions limit in section 129.97. Section
129.98(g) requires that the application for such an averaging plan
should contain, ``methods for demonstrating compliance. . . .'' The
fact that the application must have a method for determining compliance
shows that section 129.98 does not, in its text, have a method for
determining compliance with section 129.97. The presumptive limits in
section 129.97 otherwise applicable to each source must be used as a
factor in the Eiallowable equation (unless a lower emission
limit applies to a source) in 129.98 but will not be used on the
Eiactual side of the equation. Instead, actual mass
emissions from each source in the plan, as determined by CEMS or other
means, on any given day will be added together on

the Eiactual side of the equation. Thirty days of
Eiactual daily mass emissions will be added together and
divided by 30, and 30 days of daily Eiallowable mass
emissions will be added together and divided by 30. The resultant 30-
day average of Eiactual emissions on any given day must be
less than or equal to the 30-day average of Eiallowable
emissions on the same day. It will not be possible under this averaging
scheme to determine whether the individual hourly emission rate of each
source/unit met the presumptive RACT limit in section 129.97 for that
source. Thus, the provisions of 129.98 provide the formula to set the
alternative NOX emission limitation for sources who will
comply with the alternative NOX emission limitation in lieu
of the presumptive rates in 129.97.
    As previously discussed, EPA is concerned that section 129.98 lacks
a definitive method for demonstrating how the 30-day rolling average
mass NOX emission limitation allowed by 129.98 will be less
than or equal to the NOX emissions that would have been
emitted if all the sources complied with the source specific RACT
limits of 129.97, so PADEP has committed to submit these averaging
plans to EPA for approval into the SIP. The adequacy of the compliance
demonstration provisions will be assessed through both the state public
notice process and EPA's review of such SIP revisions. Thus, EPA
disagrees with the commenter that any of the assertions prevent EPA
from conditionally approving 129.98 as part of Pennsylvania's RACT.
    Comment 14: One commenter asserts that PADEP's NOX
averaging provisions in section 129.98 do not require the establishment
of an alternative NOX emissions limit; and therefore, there
is no need to submit averaging plans as separate SIP revisions to EPA.
    Response 14: EPA disagrees that Pennsylvania's NOX
averaging provisions do not require establishment of an alternative
NOX emission limit. As discussed in the March 14, 2018 NPRM,
EPA proposed to determine that the NOX averaging equation in
section 129.98(e) does '' . . . not clearly specify how to properly
establish an alternative RACT limit.'' 83 FR 11160. To do so, EPA would
need to know, at the least, what facilities and units are involved in
each plan, the applicable limits in each plan, if multiple fuels are
used, or any other information necessary to calculate
``Eiallowable.'' EPA also expressed concerns about the lack
of compliance demonstration requirements in the rule. In addressing
these deficiencies, PADEP committed to submit as SIP revisions any
alternative emissions limits and compliance demonstration requirements
approved under section 129.98. EPA has proposed approval of section
129.98 with the condition that PADEP meets this commitment to submit
additional enforceable provisions for approval into the SIP during
which time the alternative NOX emissions limit will be
clearly established.
    Comment 15: Two commenters allege that Pennsylvania's rule provides
system-wide or facility-wide NOX averaging as a means of
demonstrating compliance with the applicable emission limits included
in the rule; and requests EPA to review the averaging provisions
contained in EPA's Acid Rain Program (at 40 CFR 76.11) and the Mercury
and Air Toxics Rule (MATS rule) (at 40 CFR 63.10009) that allow
averaging as a means of demonstrating compliance.
    Response 15: EPA disagrees with the commenters that Pennsylvania's
rule provides averaging as a means of determining compliance. As
previously stated, Pennsylvania's rule specifically directs the owner
or operator to determine the ``alternative facility-wide or system-wide
NOX RACT emission limitation.'' This language requiring the
owner/operator to determine an alternative emission limitation shows
that the provisions of 25 Pa. Code 129.98 are not a means of
demonstrating compliance but rather a means to determine an alternative
emission limitation applicable to the corresponding facility or system.
    Furthermore, section 76.11(a)(3) of the Acid Rain Program
regulations require that each unit in an averaging plan must have a
contemporaneous annual emission limitation, and, also requires that
specific information be submitted that is not specified in section
129.98, such as annual heat input limits and an alternative annual
emission limitation for each unit. The equation is only one part of the
Acid Rain Program provisions, and if PADEP's section 129.98 regulation
included the additional information and other requirements of the Acid
Rain Program regulations, the equation might present an acceptable
option.
    Regarding the MATS rule equation at 40 CFR 63.10009, EPA notes
there are many additional limitations in that section which are not
present in section 129.98, such as groupings of similar sources, as
well as multiple equations (6) specifically geared toward each
grouping. In the absence of further explanation by the commenter as to
how these equations can be usefully applied to the section 129.98
averaging program, EPA does not see the MATS rule averaging scheme as
useful to resolving EPA's concerns.
    Comment 16: One commenter disagrees with EPA's interpretation that
section 129.98 requires the establishment of alternative emissions
limitations for individual sources. The commenter urges EPA to
recognize that the presumptive limits of section 129.97 are being used
to establish RACT compliance requirements, including the averaging
provisions, and that therefore these requirements should meet RACT. The
commenter asserts that the NOX averaging provisions in
section 129.98 should be adequate for approval into the SIP, because
EPA has found that the multiple fuel presumptive provision of section
129.97(g)(4) is approvable. The commenter contends that the multiple
fuel presumptive provision is similar to the NOX averaging
provisions, as they both establish weighted averaged limits. The
commenter also claims that EPA's proposed rulemaking action makes the
RACT II Rule costlier to implement and comply with and less flexible.
    Response 16: The fact that EPA has approved the source specific
RACT limits in section 129.97 does not mean that an averaging plan
which uses those limits to calculate an alternative limit is
necessarily approvable. EPA must clarify that, as proposed in our NPRM,
we do not expect new unit-specific emission limits (other than the
unit-specific limit required by presumptive RACT) to be established for
each unit covered under a system-wide or facility-wide NOX
averaging plan, but rather that an alternative limit must be determined
for each plan, which would cover the non-complying unit and any other
participating units. This is required by PADEP under 25 Pa. Code
section 129.98(e): ``The owner or operator shall calculate the
alternative facility-wide or system-wide NOX RACT emissions
limitation using a 30-day rolling average for the air contamination
sources included in the application (. . .) by using the following
equation to sum the emissions for all of the sources included in the
NOX emissions averaging plan.''
    EPA agrees with the commenter that the presumptive emission limits
in section 129.97 are used in developing the alternative NOX
limit under an averaging plan, as required by section 129.98(e);
however, EPA disagrees that they are used to establish RACT compliance
requirements. As plainly stated in section 129.98(e), the owner or
operator shall calculate an alternative facility-wide or system-wide
NOX emission limitation. Second, according to section
129.98(a), the averaging provisions of section 129.98 may only

be utilized if one or more sources covered under such a plan are unable
to meet the presumptive limits under section 129.97, and this unit
would be in violation of the applicable NOX limit in section
129.97.
    EPA disagrees with the commenter's assertion that the averaging
provisions of section 129.98(e) are similar to those under the multiple
fuel firing provisions in section 129.97(g)(4). The mathematical
formula in section 129.97(g)(4) is a weighted average formula where a
value is computed resulting from the multiplication of each component
by a factor reflecting its frequency of use. The formula in section
129.98 computes an alternative limit that is not a weighted average or
even a mathematical average, as the section's title may imply, but a
summation of all NOX mass emissions from each unit covered
under the averaging plan. Thus, the two formulae described by the
commenter are not similar in nature and are not comparable. Also, the
most substantive difference between these two requirements is that the
NOX averaging provisions of section 129.98 require an owner
or operator to establish an alternative limit covering multiple units,
including any NOX units unable to meet presumptive RACT and
any other participating units under such averaging plan; whereas
section 129.97(g)(4) establishes a presumptive RACT requirement for a
single emissions unit. This need to establish an alternative limit
under the variable ``Eiallowable'' in the equation of
section 129.98(e) is one of the main differences between the two
provisions.
    Furthermore, EPA identified several deficiencies in the averaging
provisions of section 129.98 that prevent its full approval, but those
deficiencies were not present in the multiple fuel provisions of
129.97(g)(4). Namely, EPA found that the averaging provisions of
section 129.98 do not clearly specify how to properly establish an
alternative RACT limit (under the variable ``Eiallowable'')
and do not specify sufficient compliance demonstration requirements for
sources seeking to comply with these provisions. Therefore, these
provisions were not found adequate to meet RACT. EPA disagrees with the
commenter's presumption that if section 129.97(g)(4) meets RACT, so
should section 129.98.
    Finally, although the commenter claims that EPA's proposed action
raises the cost for affected sources with regard to implementation and
compliance of the RACT II Rule, the commenter failed to specify how
EPA's action would increase costs on facilities choosing system-wide or
facility-wide averaging. Given the lack of specificity and lack of
analysis on how EPA's action requiring Pennsylvania to submit plans for
SIP approval raises costs on sources, EPA provides no further answer.
    Comment 17: The commenter argues that NOX averaging
plans under section 129.98 must provide explicit emissions limits for
individual emissions units consistent with the reasonably achievable
controls, and further recommends using historical achievable
NOX rates as the basis for establishing these limits.
Furthermore, the commenter asserts that the averaging plan must show
that the resulting NOX emission limits from the averaging
plans are more stringent than the presumptive limits that would be in
effect otherwise.
    Response 17: EPA disagrees with the commenter on each of its
assertions. First, EPA disagrees that averaging must provide explicit
emissions limitations for individual sources. In fact, under its
longstanding RACT policy, EPA has allowed NOX averaging,
recognizing that it would allow states the flexibility of establishing
RACT without requiring the imposition of source-specific controls or
consequently source-specific emissions limits. EPA has allowed
averaging for RACT purposes, as long as the state can achieve
NOX reductions less than or equal to those that would be
achieved if individual RACT emission rates were required for each
individual source. Limitations on individual sources would restrict
flexibility for meeting RACT requirements.
    EPA disagrees that averaging must result in more stringent
NOX limitations than the presumptive limits, as this is not
required under the longstanding EPA provisions permitting averaging.
See South Coast Air Quality Mgmt. Dist. v. EPA, 882 F.3d 1138, 1154
(D.C. Cir. 2018) (addressing averaging within EPA's ozone
implementation rule). EPA finds that section 129.98 requires that the
overall level of NOX emissions from units participating in
an averaging plan should be less than or equal to the total
NOX emissions which would have been emitted if each source
complied with its applicable presumptive RACT limit. See 25 Pa. Code
129.98(e).
    Comment 18: The commenter urges EPA to deny the approval of any
NOX averaging plan as a revision to the SIP, if the plan
does not provide sufficient justification for demonstrating that an
emissions unit cannot meet the applicable presumptive RACT limit.
    Response 18: EPA concurs with commenter that section 129.98(a)
requires PADEP to determine that the facility is not able to comply
with presumptive RACT in order to allow a source to comply with the
provisions in 129.98. Pennsylvania has committed to submitting permits
with the NOX averaging plans to EPA for SIP approval and EPA
will review whether sources demonstrated compliance with requirements
in 129.98 when such plans are before EPA for SIP approval.
    Comment 19: One commenter asserts that although NOX
averaging applies to NOX emitting units that cannot comply
with the presumptive limits, section 129.98 does not impose any
detailed requirements for showing that an affected NOX
emissions unit cannot comply with the presumptive NOX RACT
limits. Commenter argues that this lack of specific requirements allows
the owner or operator of the affected emissions units to make this
determination without providing any justification. Commenter further
suggests such demonstration should be based on the evaluation of past
performance for the non-complying unit.
    Response 19: EPA agrees that section 129.98 does not specifically
describe how a source must demonstrate that it is unable to meet the
applicable presumptive limit, in order to qualify for averaging under
section 129.98. However, the inability to meet the limit remains a
requirement within 129.98 for Pennsylvania to evaluate before granting
the alternative NOX plan. In addition, based on
Pennsylvania's September 2017 commitment to ``submit the terms and
conditions dealing with emissions averaging to EPA as facility specific
SIP revisions,'' EPA will review the terms of each plan and whether the
provisions in 129.98 were met. See Pennsylvania's September 26, 2017
submittal, p .2.
    Comment 20: One commenter states that PADEP's averaging provisions
allow unbounded discretion to the owner or operator in choosing which
units may be able to participate in an averaging plan, which then
allows inappropriate averaging. The commenter also contends that such
discretion would allow, for example, that coal-fired boilers with
existing controls, such as SCR or SNCR, avoid fully optimizing existing
controls; or that averaging occurs across different fuel types.
    Response 20: EPA agrees in part with the commenter's statement that
section 129.98 grants the owner or operator the ability to determine
which units should be averaged together; however, EPA disagrees with
commenter's proposition that such discretion should cause EPA to
disapprove this SIP revision. EPA believes that such discretion is
consistent with EPA's RACT policy, which allows states to use averaging
for RACT purposes as long as the level of NOX reductions due
to averaging is

equivalent to, or greater than, the level of reductions otherwise
achieved by individual application of RACT. As noted in EPA's responses
above, Section 129.98(a) requires that an owner or operator seeking to
use NOX averaging must first show that one (or more) units
to be included in the averaging plan cannot comply with the presumptive
RACT limits applicable to the unit before an averaging plan can be
considered. In addition, system-wide averaging is only allowed among
sources under common control of the same owner or operator and located
within the same ozone nonattainment area. Further, section 129.98(c)
requires that the other sources participating in a NOX
averaging plan are subject to a NOX emissions limitation
under section 129.97. Provided these conditions are met, the owner or
operator of an affected source (i.e., the source with a non-compliant
unit) may select which and how many other emissions units would be
included in the averaging plan. PADEP has also stated as part of the
SIP submittal that an owner or operator of an affected source complying
with a NOX averaging plan must demonstrate that the
NOX emissions for other units included in the averaging plan
are below the applicable limits in section 129.97 in order to provide
the cushion for averaging the excess emissions of the noncomplying
source.\18\ Thus, the discretion provided under section 129.98 to
choose which units participate in a NOX averaging plan is
not unbounded and would not allow ``inadequate averaging,'' as the
commenter proposes.
---------------------------------------------------------------------------

    \18\ See PADEP's Responses to Comments Document, Comments #137,
#138, #142, and #194.
---------------------------------------------------------------------------

    EPA recognizes that PADEP's NOX averaging may allow
units to avoid the installation of additional controls or optimization
of existing controls. However, nothing in the CAA, its regulations or
EPA guidance requires installation of additional controls or
optimization of existing controls to meet ozone RACT requirements. By
allowing states to use NOX averaging, EPA intended to
provide additional flexibility in establishing RACT, as long as RACT
level reductions are achieved for the nonattainment area. EPA does not
believe that averaging across combustion units firing different fuels
is inappropriate, nor does the commenter provide any analysis
supporting this statement.
    Comment 21: One commenter asserts that the RACT II Rule, as
written, limits system-wide averaging to areas designated nonattainment
under CAA section 107, but that PADEP appears to be considering the
rest of the Commonwealth as one giant nonattainment area. The commenter
argues that because the RACT II Rule does not have its own definition
of ``nonattainment area,'' Pennsylvania's general definition in section
121.1 applies. Section 121.1 defines ``nonattainment area'' as those
areas designated by EPA under CAA section 107.
    Response 21: Pennsylvania's RACT II Rule allows emissions averaging
to take place under two specific scenarios. In response to comments
submitted by EPA during the state rulemaking process, PADEP clarified
its interpretation of section 129.98 in the preamble to the final
regulations. See 46 PaB 2036. First, for areas formally designated as
nonattainment under CAA section 107, PADEP intended to limit emissions
averaging to sources under common control or ownership within that
formally designated nonattainment area, as this comports with
established caselaw. See Nat. Res. Def. Council v. EPA, 571 F.3d 1245
(D.C. Cir. 2009) (holding that the NOX SIP call trading plan
cannot be used for RACT averaging because emission reductions needed
for a nonattainment area must come from same nonattainment area).
Second, EPA believes PADEP intended to allow emissions averaging among
sources under common control/ownership that were outside of those areas
``formally designated'' nonattainment, but inside the state boundaries
(i.e., within the OTR attainment areas and treated as Moderate
nonattainment for SIP planning purposes in accordance with CAA section
184). That is, sources within an area formally designated as
nonattainment under CAA section 107 could use emissions averaging with
another source in the same area, and sources outside those formally
designated nonattainment areas could use emissions averaging with other
sources that are in similar attainment areas (but within the OTR area),
but no emissions averaging is allowed between sources in an area
formally designated as nonattainment under section 107 and sources in
areas designated unclassifiable or attainment within the Commonwealth,
but within the OTR.

C. Compliance Demonstration Requirements

    Comment 22: The commenter notes that the provisions in section
129.98(g)(3) and 129.98(j) refer to the compliance demonstration
requirements in section 129.100; however, the commenter states section
129.100 has no specific requirements for sources in an averaging plan.
    Response 22: As noted in the NPRM, EPA identified its concerns
regarding the provisions establishing compliance demonstration
requirements for sources seeking to comply with NOX
averaging in sections 129.98 and 129.100 of the RACT II Rule. For this
reason, EPA is requiring PADEP as part of our conditional approval to
submit for approval into the SIP any compliance demonstration
requirements for sources subject to section 129.98. This will ensure
that the alternative NOX limits under section 129.98 are
practically and Federally enforceable, pursuant to CAA section
110(a)(2)(A).
    Comment 23: The commenter contends that section 129.99(d)(6) refers
to the compliance demonstration requirements in section 129.100;
however, no specific requirements are specified for these affected
sources under section 129.100. The commenter also contends that without
existing compliance demonstration requirements, it is unclear how PADEP
will be able to approve enforceable alternative RACT proposal, and that
consequently EPA should disapprove section 129.99 of the regulation.
    Response 23: EPA notes that section 129.99(d)(6) requires a source
seeking to comply with source-specific RACT to ``[i]nclude in the RACT
proposal methods for demonstrating compliance and (emphasis added)
recordkeeping and reporting requirements in accordance with Sec.
129.100 (relating to compliance demonstration and recordkeeping
requirements) for each air contamination source included in the RACT
proposal.'' Section 129.100(d) and (i) establish recordkeeping and
reporting requirements for all sources subject to the RACT II Rule. In
addition, section 129.99(d)(1) requires the written RACT proposal to
follow the procedures in 129.92(a)(1)-(5) and (7)-(10). Section
129.92(a)(7) requires a RACT proposal to include the ``testing,
monitoring, recordkeeping and reporting procedures proposed to
demonstrate compliance with RACT.'' See 129.92(a)(7). As Pennsylvania
has committed to submitting all additional source-specific RACT SIP
provisions containing source-specific RACT limits approved by PADEP
under 129.99 to EPA for approval into the Pennsylvania SIP, EPA can
further evaluate compliance demonstration when such alternatives are
submitted for SIP approval.
    Comment 24: One commenter contends that section 129.100 does not
prescribe specific recordkeeping requirements to determine compliance
with the applicable RACT requirements in sections 129.96 to 129.99; and
for that reason, urges EPA to disapprove this

section of the RACT II Rule. Commenter argues that PADEP should have
identified specific requirements for determining compliance with
presumptive RACT and NOX averaging, such as fuel monitoring
and hours of operation, while for alternative source-specific limits,
it should have specified that compliance methods would be determined on
a case-by-case basis.
    Response 24: Neither EPA's implementation rule for the 1997 ozone
standard nor the implementation rule for the 2008 ozone standard
specifically identify those parameters, measures, or data which a
source must record in order to demonstrate compliance with RACT limits
developed by the states. See 40 CFR part 51, subparts X and AA. EPA has
issued general statements in preambles for rulemakings other than the
ozone implementation rules mentioned above discussing the monitoring
and recordkeeping requirements generally necessary for any SIP and for
NOX RACT SIPs, but these do not identify specific parameters
that must be monitored/recorded for various types of sources in order
to prove compliance, and instead directs the state to identify those
parameters. See 57 FR 13498, 13502 (April 16, 1992) (General Preamble
for the Implementation of Title I of the [CAA] Amendments of 1990); 57
FR 55620, 55624--55625 (Nov. 25, 1992) (Nitrogen Oxides Supplement to
the General Preamble for the 1990 Amendments). The commenter cites two
such parameters--fuel usage and/or hours of operation--which could have
been specified in Pennsylvania's RACT regulations for NOX
averaging and presumptive RACT. While EPA agrees that for many sources
these two parameters are useful to determine compliance, EPA does not
expect that a state's RACT SIP regulation identify, for each type of
source, each parameter which must or might be monitored by that source
in order to show compliance with the RACT limit. EPA believes that the
operating permits issued by the Commonwealth will specify the
parameters that need to be monitored to show RACT compliance. The
Pennsylvania SIP also has other recordkeeping requirements besides the
RACT II Rule (25 Pa. Code sections 129.96-129.100) which require
recordkeeping useful for determining compliance with the RACT limits.
For example, Pennsylvania has emission reporting requirements, found at
25 Pa. Code 135.1-135.5, which require almost every stationary source
of any size to maintain and make available records which ``. . . may
include records of production, fuel usage, maintenance of production or
pollution control equipment or other information determined by the
Department to be necessary for identification and quantification of
potential and actual air contaminant emissions. If direct recordkeeping
is not possible or practical, sufficient records shall be kept, to
provide the needed information by indirect means.'' 25 Pa. Code 135.5.
In addition, Pennsylvania has special monitoring provisions for sources
that have or are likely to have ``substantial impacts'' on the
maintenance of ambient air quality standards. 25 Pa. Code 139.51-
139.53. These requirements include regular testing for emissions or the
installation of continuous emission monitoring systems (25 Pa. Code
139.52) and reporting of such testing to PADEP, including ``. . .
information regarding test methods, test conditions, operating
conditions of the source or other information which may be necessary to
properly evaluate the results of emissions monitoring performed at a
source.'' 25 Pa. Code 139.53(b).
    Pennsylvania's SIP also has permitting requirements (called Plan
Applications and Plan Approvals) which require any ``air contamination
source'' to obtain a plan approval from PADEP prior to constructing,
modifying, reactivating, or installing an air pollution control device
on such source. 25 Pa. Code 127.11. A plan application must, inter
alia, ``(3) Show that the source will be equipped with reasonable and
adequate facilities to monitor and record the emissions of air
contaminants and operating conditions which may affect the emissions of
air contaminants and that the records are being and will continue to be
maintained . . .'' 25 Pa. Code 127.12(a)(3). The permit (plan approval)
must contain the monitoring, recordkeeping and reporting requirements
in 25 Pa. Code 139, any such requirements in Article III
(Pennsylvania's Air regulations), and any other CAA monitoring,
recordkeeping and reporting requirements required. 25 Pa. Code
127.12b(c). Finally, the operating permit requirements for major
sources in 25 Pa. Code 127.401-127.406 also contain similar monitoring,
recordkeeping, and reporting requirements. See 25 Pa. Code
127.411(a)(4), 127.441(c), and 127.442.
    EPA believes that given the lack of specific requirements in EPA's
RACT regulations for the 1997 or 2008 ozone NAAQS, the recordkeeping
and reporting requirements of Pennsylvania's RACT II Rule in 25 Pa.
Code 129.100 are sufficient for approval of the RACT SIP. Also,
Pennsylvania has many other monitoring and recordkeeping requirements
potentially applicable to RACT sources that provide ample authority to
Pennsylvania, through various mechanisms, to obtain any information
necessary to show compliance with the RACT limits. Thus, EPA does not
believe Pennsylvania's RACT regulations must be disapproved, in whole
or in part, for lack of specificity concerning monitoring and
recordkeeping to show RACT compliance.

D. Averaging Time for Compliance Demonstration

    Comment 25: Commenters allege that EPA failed to consider the
averaging times of Pennsylvania's NOX presumptive emission
limits. Commenters contend that a 30-day averaging period is too
lenient and inconsistent with RACT in other OTR states, which use
averaging periods as short as 1-hour or 24-hours averages. Commenters
also allege that 30-day NOX averaging may allow sources to
emit more NOX on days when conditions are conducive to ozone
formation that might lead to an exceedance of the NAAQS.
    Response 25: EPA disagrees with the commenters. During EPA's review
of Pennsylvania's RACT II Rule, EPA compared Pennsylvania's presumptive
limits with those of other OTR states. In Appendix B of EPA's TSD, EPA
provided the emission limits for other OTR states while noting the
difference between those states' rules and Pennsylvania's rule below
each table in the TSD.
    PADEP determined that a 30-day rolling average limit addresses
problems faced by certain owners and operators, including variability
in fuel source, emission spikes during start-ups, shutdowns, and
malfunctions, and other unavoidable circumstances. PADEP determined
that these situations are not indicative of normal operations and so it
would not be appropriate to require facilities to show compliance with
the presumptive NOX RACT emission limit over a 1-hour or 8-
hour averaging period as such variability would affect technical and
economic feasibility of sources to meet the presumptive limits making
compliance either technically infeasible or cost ineffective. PADEP
selected the 30-day rolling average to ensure technical and economic
feasibility for Pennsylvania sources to meet RACT. PADEP reasons that
to maintain compliance with a 30-day rolling average, sources will have
to operate below the allowable standard on some days in order to
account for potential days of higher emissions. PADEP also notes that
EPA has

approved 30-day rolling averages as ``short-term'' RACT limitations in
SIP revisions submitted by New York and Wisconsin. See 75 FR 64155
(October 19, 2010) for Wisconsin and 78 FR 41846 (July 12, 2013) for
New York.

E. Cost Effectiveness

    Comment 26: One commenter contends that PADEP did not perform any
cost effectiveness evaluation while setting the presumptive limits and
argues that EPA cannot supplement a state's faulty or deficient SIP.
The commenter alleges that EPA's performance of a cost-effective
analysis in the second TSD shows both the necessity for such an
analysis and that PADEP did not perform a cost-effectiveness analysis
and therefore Pennsylvania's SIP revisions lacked an adequate RACT
evaluation.
    Response 26: EPA disagrees that PADEP did not perform any cost-
effectiveness evaluation when establishing presumptive limits under the
RACT II Rule. PADEP relied on a cost-effectiveness of $2,800 per ton of
NOX controlled and $5,500 per ton of VOC controlled for the
presumptive limits in the RACT II Rule.\19\ As mentioned in PADEP's
final rulemaking, Pennsylvania's Environmental Quality Board (EQB)
stated that the Regulatory Analysis Form (RAF) was ``replete with
substantive information regarding emissions data, cost-effectiveness
numbers, public health information, statutory requirements, small
business information and other types of analyses to demonstrate that
the regulations are legally required, in the public interest,
economically and technologically feasible, and will reduce emissions.''
The EQB also stated ``[t]he presumptive RACT emission limitations were
established based on cost-effectiveness of available control
technology. . . .'' Thus, EPA believes that PADEP did in fact perform a
cost-effectiveness evaluation in order to determine what emission
limitations and control technologies were technologically and
economically feasible.
---------------------------------------------------------------------------

    \19\ See PADEP's Responses to Comments Document, Docket item
#0004 Comments #13 and #111.
---------------------------------------------------------------------------

    Also, EPA disagrees that it ``supplemented'' the state's SIP
submission by performing and referring to its own analysis of cost for
very large coal-fired boilers with SCR and SNCR in the second TSD. EPA
performed this analysis in support of our evaluation of the
reasonableness of PADEP's cost-effectiveness threshold of $2,800 per
ton of NOx controlled and the resulting emission limits derived for
coal-fired boilers in the RACT II Rule. EPA focused its evaluation on
this source category because it is the largest NOX emitting
sector in Pennsylvania. EPA's evaluation in the TSD supported our
conclusion that Pennsylvania's RACT was reasonable and does not
indicate that Pennsylvania's SIP was therefore inadequate or lacking
information.
    Comment 27: Two commenters claimed that Pennsylvania's cost
effectiveness thresholds for NOX and/or VOC were too low
compared to adjoining states (New York, New Jersey, and Delaware) in
the OTR and states sharing nonattainment areas with Pennsylvania. One
commenter referred to New York's threshold of $5,000 to $5,500 per ton
of NOX for coal-fired units and pointed to New Jersey's and
Delaware's consideration of best available control technology (BACT) as
cost effective controls to meet RACT, even when not using specific
cost-effectiveness benchmarks.
    Response 27: EPA is aware that Pennsylvania considered cost-
effectiveness levels that are lower than other states in the OTR when
developing the RACT II Rule; however, states have the discretion to
determine what costs are considered reasonable when establishing RACT
for its sources. For these reasons, EPA has not set a single cost,
emission reduction, or cost-effectiveness figure to fully define cost-
effectiveness in meeting the NOX RACT requirement.
Therefore, each state must make and defend its own determination on how
to weigh these values in establishing RACT.
    PADEP relied on a cost-effectiveness of $2,800 per ton of
NOX controlled and $5,500 per ton of VOC controlled for the
presumptive limits in the RACT II Rule.\20\ In considering similar
comments received during its proposal of the rule concerning cost-
effectiveness, PADEP determined that ``[e]ven with an additional 25%
margin, the upper bound cost-effectiveness threshold would not be any
greater than $3,500 per ton NOX controlled'' and ``$7,000
per ton VOC controlled,'' and that ``[a]pplying these new thresholds
does not have an effect on the add-on control technology decisions for
the presumptive RACT requirements established in the final
rulemaking.'' PADEP concluded that the RACT presumptive limits included
in final form of the RACT II Rule ``are comparable to emission limits
included in other states' RACT regulations as well.'' \21\
---------------------------------------------------------------------------

    \20\ See PADEP's Responses to Comments Document, Docket item
#0004, Comments #13 and #111.
    \21\ See PADEP's Responses to Comments Document, Docket item
#0004, Comment #13
---------------------------------------------------------------------------

    Further, while cost effectiveness is an important consideration, it
must be noted that other factors should be integrated into a RACT
analysis, such as emission reductions and environmental impact. As
stated above, Pennsylvania determined higher cost thresholds did not
impact feasible add on control technology. And, as discussed earlier,
EPA believes that PADEP's presumptive limits are reasonable as they
reflect control levels achieved by the application and consideration of
available control technologies, after considering both the economic and
technological circumstances of Pennsylvania's own sources. EPA also
finds that Pennsylvania's presumptive limits are comparable to those
adopted in other states for similar sources.\22\
---------------------------------------------------------------------------

    \22\ See EPA's TSD, section IV.C.
---------------------------------------------------------------------------

F. Alternative Compliance Schedules

    Comment 28: One commenter argues that sources petitioning for
alternative compliance schedules, as allowed under section 129.97 and
129.99, should be required to submit the alternative compliance dates
and interim emissions limits to EPA for inclusion in the SIP. Commenter
further argues that without incorporating these into the SIP,
facilities would be liable for violating the SIP-approved compliance
deadline of Jan 1, 2017 and the applicable presumptive limits.
    Response 28: Regarding section 129.99, section 129.99(h) explicitly
states that alternative RACT requirements or emission limitations
requested under subparts 129.99(a), (b) and (c) and approved under
129.99(f) will be submitted to EPA for approval into the SIP.
Pennsylvania has also committed to submitting to EPA all source-
specific RACT determinations under section 129.99 for approval as a SIP
revision within 12 months of EPA's final rulemaking. Therefore, the
commenter's concern that alternative compliance schedules issued under
section 129.99 should be submitted to EPA for approval as part of the
SIP is already being addressed by the language of section 129.99(h) and
Pennsylvania's September 26, 2017 committal to submit permits with
schedules under 129.99 to EPA for inclusion in the SIP; PADEP will be
submitting any section 129.99 alternative compliance schedule and the
emission limits to EPA as a formal SIP revision. EPA will evaluate and
act accordingly on any SIP revision

submitted with alternative compliance schedules in a future rulemaking
action.
    For alternative compliance schedules in section 129.97(k), EPA
believes that PADEP intends to submit all such alternative compliance
schedules to EPA for approval into the SIP. EPA finds the schedules
discussed in section 129.97(k) are also included within the scope of
section 129.99 (and thus within Pennsylvania's September 26, 2017
commitment) because section 129.99(i) addresses how sources can get an
alternative RACT requirement or alternative RACT emission limit when
installing an air cleaning device and section 129.99(i) provides the
process and details needed for sources to petition PADEP for an
alternative. Section 129.97(k) provides one such alternative RACT
requirement within the meaning of section 129.99(i) as it provides that
sources which cannot meet presumptive limits without installing an air
cleaning device may petition PADEP for additional time to comply. Thus,
any source seeking an alternative under section 129.97(k) (because it
needs to install an air cleaning device) is also subject to section
129.99 (via 129.99(i) as a source seeking an alternative RACT
requirement due to installation of an air cleaning device), and PADEP
has committed in its September 26, 2017 letter to sending all such
alternative RACT proposals to EPA for SIP approval.
    Sources that did not need to install equipment and/or modify
permits to meet the presumptive RACT requirements in 25 Pa. Code 129.96
were required to comply with presumptive RACT by the January 1, 2017
deadline. Existing sources that could not meet presumptive RACT without
installation of an air cleaning device were required to petition PADEP
to request an alternative compliance schedule by October 24, 2016 and
include a compliance schedule no longer than three years from the date
of PADEP's approval of the petition, with interim emission limits and
compliance dates. 25 Pa. Code 129.97(k). PADEP provided a list to EPA
on March 22, 2019 of sources receiving alternative compliance schedules
under 25 Pa. Code 127.97(k) or 127.99(i) showing that eight of the nine
sources are presently complying with presumptive RACT requirements or
more stringent emission limits known as ``best available technology''
limits to which new sources in Pennsylvania are subject. The ninth
source will achieve full compliance with presumptive RACT by Fall of
2019. EPA has included the list from Pennsylvania in the docket for
this rulemaking action available online at www.regulations.gov.
    Given the relatively small number of sources seeking alternative
compliance schedules under 25 Pa. Code 129.97(k), the majority of
sources currently in compliance with presumptive RACT and the remaining
source complying with presumptive RACT imminently, and given PADEP's
commitment to have permits issued under 25 Pa. Code 127.99 (inclusive
of 127.97(k)) included in the SIP, the extensions of time granted by
PADEP's regulations after the January 1, 2017 RACT compliance deadline
are not unreasonable as RACT is being implemented within the
Commonwealth. Moreover, there is no ability for EPA to ``turn back the
clock'' and have these sources comply by 2017 at this date. For these
reasons, EPA believes that the provisions in 127.97 and 129.99
regarding compliance dates are reasonable and approvable (with the
caveat that 127.99 is subject to conditional approval for submission of
permits for SIP approval) for RACT as compliance is complete or nearly
complete. EPA will evaluate and act accordingly on any permits
submitted to EPA for SIP-approval at a future time through a future
rulemaking action.
    Comment 29: Commenter argues that for sources receiving alternative
compliance schedules under sections 129.97 or 129.99 extending beyond
January 1, 2017, PADEP should be required to submit the alternative
compliance dates and interim emissions limits to EPA for possible
approval into the SIP. Commenter urges EPA to confirm that alternative
compliance schedules or limits are not Federally enforceable, unless
PADEP submits them to EPA and EPA approves them into the SIP.
    Response 29: In 25 Pa. Code section 129.99(h), PADEP explicitly
states that PADEP will submit the alternative RACT requirement or RACT
emission limitation requested to EPA for approval into the SIP. In
addition, PADEP has committed to submitting to EPA any alternative RACT
schedules and proposals received under section 129.99, which includes
those submitted under 25 Pa. Code 127.97(k) as discussed in response to
prior comments. EPA will evaluate and act accordingly on any
alternative compliance schedule or alternative RACT emission limit
submitted for SIP-approval at a future time through a future rulemaking
action. EPA will evaluate the reasonableness of any extension of time
for RACT compliance beyond Pennsylvania's January 1, 2017 deadline when
the SIP is submitted to EPA. In response to Comment #28, EPA addressed
the timing of sources complying with alternative RACT. Regarding
Federal enforceability, EPA agrees that any alternative RACT emission
limits and/or alternative compliance schedules approved by PADEP which
are not submitted to EPA for approval into the SIP would not be
Federally-enforceable under the SIP; however, these limits may be
included in some other type of Federally-enforceable permit.
    Comment 30: One commenter argues that EPA cannot approve section
129.99(i)(2)(v) for sources petitioning alternative compliance
schedules, because it allows a compliance date later than January 1,
2017, as required by EPA's ozone implementation regulation in 40 CFR
51.1112(a)(3). Commenter states that EPA must disapprove this provision
of the regulation, as it is in violation of EPA's own regulations.
    Response 30: EPA issued the 2008 ozone attainment designations for
numerous areas of the country, including designating five areas in
Pennsylvania as Marginal nonattainment areas, on May 21, 2012. See 77
FR 30088 and 40 CFR 81.339. On March 6, 2015, EPA issued its final rule
for implementation of the 2008 ozone NAAQS (the ``2008 Ozone SIP
Requirements Rule''). See 80 FR 12264 and 40 CFR 51.1100-51.1103. The
2008 Ozone SIP Requirements Rule set a deadline for submission of RACT
SIP revisions for VOC and NOX of two years after the
designations effective date of July 20, 2012 or July 20, 2014 and a
deadline for implementation of RACT of January 1, 2017. See 77 FR 30088
and 40 CFR 51.1112(a)(2). After EPA issued the 2008 Ozone SIP
Requirements Rule, PADEP submitted its SIP revision on May 16, 2016 to
implement the RACT requirements for the 1997 and 2008 ozone NAAQS.
These regulations became final at the state level on April 23, 2016.
    Sources in Pennsylvania subject to RACT for the 1997 and 2008 ozone
NAAQS generally had slightly more than seven months from the state
effective date of Pennsylvania's RACT regulations to meet the January
1, 2017 deadline. Advance planning by RACT sources in reliance upon
Pennsylvania's proposed RACT limits before they became final at the
state level on April 23, 2016 would have been imprudent because
Pennsylvania both lowered and raised the presumptive RACT limits for
multiple types of sources following the public comment period, which
illustrates the uncertainty sources faced while trying to plan for
implementation of RACT standards. For a list of changes

to the presumptive limits following Pennsylvania's proposal, see Table
1.

      Table 1--Changes in Presumptive Limits From Proposal to Final
------------------------------------------------------------------------
  Presumptive citation (129.97)     Proposed limit        Final limit
------------------------------------------------------------------------
(g)(1)(i)--Natural gas unit,      0.08 lbs/MMBTU....  0.10 lbs/MMBTU.
 heat input >=50 MMBTU/hr.
(g)(1)(vi)(A)--coal fired CFB     0.20 lbs/MMBTU....  0.16 lbs/MMBTU.
 unit >=250 MMBTU/hr.
(g)(2)(i)(B)--combined cycle      75 ppmvd NOX......  96 ppmvd NOX.
 turbine >=1,000 bhp, <180 MW;
 fuel oil.
(g)(2)(i)(C)--combined cycle      2 ppmvd VOC.......  5 ppmvd VOC.
 turbine >=1,000 bhp, <180 MW;
 natural gas.
(g)(2)(i)(D)--combined cycle      2 ppmvd VOC.......  9 ppmvd VOC.
 turbine >=1,000 bhp, <180 MW;
 fuel oil.
(g)(2)(iv)(B)--simple cycle       75 ppmvd NOX......  96 ppmvd NOX.
 turbine >=6,000 bhp; fuel oil.
(g)(3)(i)(B)--lean burn           0.4 grams VOC/bhp-  1.0 grams VOC/bhp-
 stationary internal combustion    hr.                 hr.
 engine, >=500 bhp; Natural gas
 or noncommercial gaseous fuel.
(g)(1)(vii)--new limit for solid  N/A...............  0.25 lbs/MMBTU.
 fuel fired combustion units
 >=50 MMBTU/hr.
(g)(1)(viii)--new limit for coal  N/A...............  0.12 lbs/MMBTU.
 fired units with SCR; when >=
 600[deg]F.
(g)(1)(ix)--new work practice     N/A...............  Inject ammonia.
 standard for coal fired units
 with SNCR.
(g)(2)(iii)(A), (B), (C), and     N/A...............  150 ppmvd NOX 9
 (D)--simple cycle turbine                             ppmvd VOC.
 >=1,000 bhp, <6,000 bhp; firing
 natural gas or fuel oil.
------------------------------------------------------------------------

    Pennsylvania sources relying on the presumptive limits in
Pennsylvania's proposed RACT II Rule could find themselves ordering
equipment to meet RACT limits that they didn't need because they could
meet the increased limit in the final rule without additional equipment
or could find themselves ordering inadequate equipment to meet a
NOX limit that was lowered by the final rule.
    On April 6, 2017, EPA proposed approval of revisions to
Connecticut's RACT regulations for the 2008 ozone NAAQS. See 83 FR
16772. These revisions included new NOX limits for MWCs with
a compliance date of August 2, 2017, and new NOX limits for
boilers, turbines, and reciprocating internal combustion engines (RICE)
with a compliance date of June 1, 2018. See 83 FR 16772, 16773 (April
6, 2017). Among other reasons, EPA justified these compliance deadlines
beyond the January 1, 2017 Federal regulatory deadline because the
sources subject to the new RACT limits were a small subset of all the
facilities subject to RACT and were already subject to RACT controls in
the SIP that would be further tightened by the new revisions. See 83 FR
16772, 16776. EPA also justified the post-January 2017 dates based on
the fact that it was impossible for sources to retroactively meet the
January 1, 2017 deadline, and agreed with Connecticut's determination
that given the August 2, 2016 and December 22, 2016 state effective
dates for the new MWC limits and combustor limits, respectively, it
would not be reasonable to require immediate compliance. Likewise, for
Pennsylvania, EPA finds it would be impossible for sources today to
retroactively meet the January 1, 2017 deadline for implementation of
RACT. Like Connecticut, Pennsylvania had also implemented in its SIP
RACT requirements on all major sources of NOx and VOCs for the prior 1-
hour ozone NAAQS. See 40 CFR 52.2020(d). In addition, for sources
needing installation of controls to meet requirements of the RACT II
Rule after the Rule became state effective in 2016, such sources needed
time to select controls, apply for permits and implement, install and
begin operating such controls to meet RACT II Rule limits.
    For the above reasons, EPA finds the provisions in Pennsylvania's
rules providing for additional time to comply in 25 Pa. Code section
127.97 and 127.99 allowed sources installing new emission controls to
meet RACT a reasonable time to comply. Thus, EPA is approving the
provisions in 129.97 and conditionally approving the provisions of
129.99.

G. Other Comments

    Comment 31: The commenter asks whether section 129.96(d), which
states that the requirements of sections 129.96-129.100 do not apply to
the owner and operator of a facility which is not a major
NOX or major VOC emitting facility on or before January 1,
2017, would allow an otherwise major NOX or VOC source to
obtain a synthetic minor permit before 1/1/17 to avoid 2008 RACT, then
``shed'' its minor status after 1/1/17 and remain not subject to 2008
RACT. The commenter argues that facilities that become synthetic minor
NOX or VOC sources before January 1, 2017 to avoid RACT
should take enforceable permit limits and that such limits should be
submitted to EPA for approval into the SIP.
    Response 31: EPA acknowledges that, generally, major sources may
take enforceable restrictions to reduce their facility-wide potential
emissions to avoid the definition of a major NOX or VOC
source. However, EPA interprets that because the RACT II Rule is only
applicable to sources that met the ``major NOX/VOC source
definition'' by January 1, 2017, any major sources without Federally-
enforceable restrictions by such date must be required to comply with
the RACT II Rule.
    Furthermore, if any facility which takes such restrictions seeks to
later ``shed'' its minor source status after January 1, 2017, the
facility would then become a major source through its ``modification''
and would then be subject to the RACT II Rule via 25 Pa Code 129.96(b).
This subsection requires facilities that become a major source to be
subject to the RACT II Rule which has ongoing applicability. Thus, EPA
believes it is unnecessary to require enforceable restrictions to be
submitted to EPA for SIP approval as the facility would be subject to
the RACT II Rule if it shed its minor limits and became a major source
of NOX or VOC.
    Comment 32: The commenter argues that EPA's approval of section
129.97(b)(1)(i)-(iii), requiring biennial tune-up for units between 20
to 50 MMBTU/hr, would be backsliding as there are similar RACT
provisions previously approved in the Pennsylvania SIP, in 25 Pa. Code
sections 129.91-95, that are more stringent because they require annual
tune-ups.
    Response 32: EPA disagrees with the commenter's assertion that EPA
is allowing ``backsliding'' by approving the provisions in section
129.97(b)(1). Commenter seems to be referring to the provisions in
129.92(b)(2)(i)-(iii), which also require tune-up for units between 20
to 50 MMBTU/hr, but on an annual basis. EPA acknowledges that the
requirements in section 129.92(b)(2)(i)-

(iii) require an annual tune-up, while section 129.97(b)(1)(i)-(iii)
only requires a tune-up once every two years. However, EPA does not
believe that relaxation of the SIP is occurring because section
129.97(i) requires sources to comply with section 129.97 unless a RACT
permit issued prior to April 23, 2016 under 129.91-95 has more
stringent requirements or limits. Based on the requirement in section
129.97(i), individual sources in Pennsylvania with RACT permits issued
prior to April 23, 2016 would not be backsliding because they would
remain subject to the more stringent annual tune-up requirements of
129.92(b)(2)(i)-(iii). Only relatively newer sources (not subject to
the prior RACT requirement for annual tune up) would be subject to the
biennial tune-up requirements of section 129.97(b)(1)(i)-(iii). Thus,
EPA believes any relaxation concerns with respect to tune-up
requirements for units between 20 to 50 MMBTU/hr are fully addressed by
the provisions of section 129.97(i).
    Comment 33: Commenter requests EPA to justify how the provisions in
section 129.97(c) and (d), requiring owners or operators to install,
maintain, and operate the source in accordance with the manufacturer's
specifications and with good operating practices, are enforceable as a
practical matter.
    Response 33: The requirement to ``install, maintain and operate the
source in accordance with the manufacturer's specifications'' is a
practically enforceable requirement as the manufacturer specifications
for control equipment at any particular source are usually available
and defined. A requirement to operate in line with ``good operating
practices'' is practically enforceable because good operating practices
can be defined within a source or industry. This is consistent with
EPA's prior approval of similar RACT provisions for the Commonwealth.
    Comment 34: One commenter alleges that EPA cannot rely on the
document titled ``PADEP's RACT II Supplemental Submittal'' for its
rulemaking action, as this document did not undergo adequate public
participation as a SIP revision, as required in 40 CFR 51.102, 51.103,
51.104 and Appendix V.
    Response 34: EPA is relying only on that portion of PADEP's
September 26, 2017 submittal (titled ``PADEP's RACT II Supplemental
Submittal'') that contains PADEP's commitments to further supplement
the SIP within one year of EPA's final conditional approval.
Information in PADEP's supplemental submittal that is not relevant to
PADEP's commitment to address EPA's conditions is not needed nor relied
upon in EPA's rulemaking herein. The nature of a conditional approval
under CAA section 110(k)(4) is such that when EPA's review of a formal
SIP submission identifies a deficiency in the SIP that could be
remedied by state action within one year of the final conditional
approval, the NPRM sets forth the conditions the state must satisfy
within one year to correct the deficiencies. The state must provide a
committal letter to EPA stating that it will fulfill EPA's requirements
for the commitment. The opportunity for public comment upon the
adequacy of EPA's conditions and the ability of the state to meet those
conditions occurs during the public comment period announced by the
NPRM. EPA does not consider a state's conditional approval committal
letter to be a SIP revision under 40 CFR 51.102(a), 51.103, 51.104, or
the completeness criteria in Appendix V to Part 51. The provisions in
Appendix V related to requirements for states to conduct public hearing
and follow state administrative procedural requirements relate to the
plan submitted by the state. Pennsylvania complied with requirements in
40 CFR part 51 and Appendix V relating to submission of its ``plan'' or
SIP submittal (i.e., the May 16, 2016 SIP submittal which includes
provisions in 25 Pa. Code 121.1, 129.96, 129.97, 129.98, 129.99 and
129.100). Pennsylvania's supplemental material from September 2017 was
additional supportive information Pennsylvania had regarding its RACT
provisions and was about Pennsylvania's commitment to submit
alternative RACT requirements and emission limitations to EPA for SIP
approval. Thus, EPA disagrees with the commenter that Pennsylvania's
September 26, 2017 provision to EPA needed to undergo additional
``public participation as a SIP revision.''
    Comment 35: The commenter claims EPA should better define the
conditional nature of EPA's approval and EPA should fully develop
methods and conditions which Pennsylvania would need to address for
full approval.
    Response 35: EPA disagrees with the commenter. EPA's NPRM clearly
specified what PADEP needed to do to correct the deficiencies
identified in the NPRM relating to section 129.98 NOX
averaging provision and section 129.99 for alternative RACT
requirements or emission limitations. See 83 FR 11155, 11160-62. EPA
has also restated the conditions and deficiencies in this rulemaking.
See Section II of this rulemaking action.
    Comment 36: The commenter claims that section 129.98 and 129.99 do
not conform with CAA section 110(a)(2)(A), as they are not practically
and Federally enforceable, and recommends EPA to disapprove these
provisions until Pennsylvania adopts specific enforceable measures.
    Response 36: The commenter has not provided adequate argument,
analysis, or specific information for EPA to account for this comment.
Thus, no further response is needed. However, EPA will note that we are
conditionally approving section 129.98 and 129.99 based on the
deficiencies we identified in the NPRM and based on Pennsylvania's
commitment to submit permits and plans to EPA for SIP approval. With
respect to the issue of practical enforceability as it pertains to
section 110(a)(2)(A), EPA finds that section 129.99 is practically
enforceable, as the regulation lays out the process for sources to
obtain source-specific RACT requirements for affected sources. PADEP
would then subsequently submit to EPA such permits for approval into
the SIP. EPA proposed conditional approval of section 129.99 because it
lacked a date certain by which PADEP would submit the relevant source-
specific RACT SIP revisions to EPA.
    As discussed in detail in the NPRM and in this action, EPA did have
concerns with enforceability of 129.98 and thus we are conditionally
approving 129.98. EPA's conditional approval of these provisions will
ensure that practical, enforceable RACT emissions limits are
established under 25 Pa. Code sections 129.98 and 129.99, consistent
with CAA section 110(a)(2)(A).
    Comment 37: Commenter believes that the required elements of
section 110(a)(2) of CAA have been fully addressed by PADEP's SIP
submittal for the RACT II Rule, particularly referring to section
110(a)(2)(A), (C), and (F). The commenter asserts that a specific
method of compliance is not required under section 110(a)(2), if the
applicable emission limits and related requirements are already part of
the rule.
    Response 37: EPA identified deficiencies in 25 Pa. Code section
129.98 pertaining to the requirement in CAA section 110(a)(2)(A) for
enforceable limits because 129.98 did not adequately establish how to
compute an alternative NOX emissions limitation and/or
adequately specify the methods for demonstrating compliance and
recordkeeping and reporting requirements for emissions averaging. EPA's
conditional approval of 25 Pa. Code section 129.98 will ensure that
practical enforceable emissions limits for CAA 110(a)(2) are
established as

RACT through SIP approval of each averaging plan.

IV. Terms of the Conditional Approval

    On September 26, 2017, PADEP submitted a letter detailing its
commitments to provide additional SIP revisions to correct various
deficiencies identified by EPA as present in the May 16, 2016 SIP
submittal. In that letter, PADEP committed to submitting to EPA, for
approval into the SIP, any facility-wide or system-wide averaging plan
approved under 25 Pa. Code section 129.98 and any source-specific RACT
determinations under 25 Pa. Code section 129.99. PADEP committed to
submitting these additional SIP revisions within 12 months of EPA's
final conditional approval.
    Therefore, as authorized in CAA section 110(k)(3) and (k)(4),
Pennsylvania shall submit the following as source-specific SIP
revisions for EPA's approval as a condition of approval of 25 Pa. Code
128 and 129 in the May 16, 2016 SIP revision: (1) All facility-wide or
system-wide averaging plans approved by PADEP under 25 Pa. Code section
129.98 including, but not limited to, any terms and conditions that
ensure the enforceability of the averaging plan as a practical matter
(e.g., any monitoring, reporting, recordkeeping, or testing
requirements); and (2) all source-specific RACT determinations approved
by PADEP under 25 Pa. Code section 129.99, including any alternative
compliance schedules approved under section 129.97(k) and 129.99(i);
the source-specific RACT determinations submitted to EPA for approval
into the SIP should include any terms and conditions that ensure the
enforceability of the source-specific RACT emission limitation as a
practical matter (e.g., any monitoring, reporting, recordkeeping, or
testing requirements).

V. Final Action

    EPA is fully approving 25 Pa. Code sections 121.1, 129.96, 129.97,
and 129.100 as meeting certain aspects of major stationary source RACT
in CAA section 172, 182, and 184 for the 1997 and 2008 ozone NAAQS
submitted May 16, 2016. EPA is also conditionally approving 25 Pa. Code
sections 129.98 and 129.99 based on the commitment provided by
Pennsylvania to submit additional SIP revisions to address the
deficiencies identified by EPA in the May 16, 2016 SIP revision. Upon
submission of all elements intended to meet the conditions identified
in Section IV of this rulemaking action, Pennsylvania must submit a SIP
revision certifying that it has met all conditions. Once EPA has
determined that Pennsylvania has satisfied these conditions, EPA shall
remove the conditional nature of this approval and Pennsylvania's 1997
and 2008 8-hour ozone RACT SIP revision will, at that time, receive a
full approval status. Should Pennsylvania fail to meet the conditions
specified in Section IV, the final conditional approval of 25 Pa. Code
sections 129.98 and 129.99 shall automatically convert to a disapproval
and EPA will issue a finding of disapproval. A finding of disapproval
would start an 18-month clock to apply sanctions under CAA section
179(b) and a two-year clock for a Federal implementation plan under CAA
section 110(c)(1).

VI. Incorporation by Reference

    In this document, EPA is finalizing regulatory text that includes
incorporation by reference. In accordance with requirements of 1 CFR
51.5, EPA is finalizing the incorporation by reference of the following
sections of 25 Pa. Code with a state effective date of April 23, 2016:
25 Pa. Code section 121.1, 129.96, 129.97, 129.98, 129.99 and 129.100;
the list of definitions contained in 121.1 and the changes being made
can be found in the TSD for this rulemaking action. EPA has made, and
will continue to make, these materials generally available through
www.regulations.gov and at the EPA Region III Office (please contact
the person identified in the For Further Information Contact section of
this preamble for more information). Therefore, these materials have
been approved by EPA for inclusion in the SIP, have been incorporated
by reference by EPA into that plan, are fully Federally enforceable
under sections 110 and 113 of the CAA as of the effective date of the
final rulemaking of EPA's approval, and will be incorporated by
reference in the next update to the SIP compilation.\23\
---------------------------------------------------------------------------

    \23\ 62 FR 27968 (May 22, 1997).
---------------------------------------------------------------------------

VII. Statutory and Executive Order Reviews

A. General Requirements

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely approves state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866.
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this rule does not have tribal implications as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000),
because the SIP is not approved to apply in Indian country located in
the state, and EPA notes that it will not impose substantial direct