Document ID: EPA-R03-OAR-2017-0290-0046
Agency: epa
Document Type: Rule
Title: Air Quality State Implementation Plans; Approval and Promulgation: Pennsylvania; Regulatory Amendments Addressing Reasonably Available Control Technology Requirements Under the 1997 and 2008 8-Hour Ozone National Ambient Air Quality Standards
Posted Date: 2019-05-09T04:00Z

[Federal Register Volume 84, Number 90 (Thursday, May 9, 2019)]
[Rules and Regulations]
[Pages 20274-20292]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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 schulingkamp.joseph@epa.gov.

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

[[Page 20275]]

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

[[Page 20276]]

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

[[Page 20277]]

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

[[Page 20278]]

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

[[Page 20279]]

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

[[Page 20280]]

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

[[Page 20281]]

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

[[Page 20282]]

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

[[Page 20283]]

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

[[Page 20284]]

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

[[Page 20285]]

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

[[Page 20286]]

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

[[Page 20287]]

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

[[Page 20288]]

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)-

[[Page 20289]]

(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

[[Page 20290]]

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 
costs on tribal governments or preempt tribal law.

B. Submission to Congress and the Comptroller General

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must

[[Page 20291]]

submit a rule report, which includes a copy of the rule, to each House 
of the Congress and to the Comptroller General of the United States. 
EPA will submit a report containing this action and other required 
information to the U.S. Senate, the U.S. House of Representatives, and 
the Comptroller General of the United States prior to publication of 
the rule in the Federal Register. A major rule cannot take effect until 
60 days after it is published in the Federal Register. This action is 
not a ``major rule'' as defined by 5 U.S.C. 804(2).

C. Petitions for Judicial Review

    Under section 307(b)(1) of the CAA, petitions for judicial review 
of this action must be filed in the United States Court of Appeals for 
the appropriate circuit by July 8, 2019. Filing a petition for 
reconsideration by the Administrator of this final rule does not affect 
the finality of this action for the purposes of judicial review nor 
does it extend the time within which a petition for judicial review may 
be filed and shall not postpone the effectiveness of such rule or 
action. This action, on Pennsylvania's RACT II Rule, may not be 
challenged later in proceedings to enforce its requirements. (See 
section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Nitrogen dioxide, Ozone, Reporting and recordkeeping 
requirements, Volatile organic compounds.

    Dated: April 25, 2019.
Cosmo Servidio,
Regional Administrator, Region III.

    40 CFR part 52 is amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart NN--Pennsylvania

0
2. In Sec.  52.2020, the table in paragraph (c)(1) is amended by 
adding:
0
a. Under ``Chapter 121--General Provisions,'' an entry for ``Section 
121.1'' after an existing entry for ``Section 121.1''; and
0
b. Under ``Chapter 129--Standards for Sources,'' after the entry for 
``129.95'', a subheading entitled ``Additional RACT Requirements for 
Major Sources of NOX and VOCs'' and the entries ``Section 
129.96'' through ``Section 129.100'' in numerical order.
    The additions read as follows:

Sec.  52.2020  Identification of plan.

* * * * *
    (c) * * *
    (1) * * *

----------------------------------------------------------------------------------------------------------------
                                                          State                          Additional explanation/
         State citation             Title/subject    effective date   EPA approval date  Sec.   52.2063 citation
----------------------------------------------------------------------------------------------------------------
                          Title 25--Environmental Protection Article III--Air Resources
----------------------------------------------------------------------------------------------------------------
                                         Chapter 121--General Provisions
 
                                                  * * * * * * *
Section 121.1..................  Definitions.......         4/23/16  5/9/19, [insert     Revises the following
                                                                      Federal Register    definitions: ``CEMS--
                                                                      citation].          Continuous emission
                                                                                          monitoring system,''
                                                                                          ``Major NOX emitting
                                                                                          facility,'' ``Major
                                                                                          VOC emitting
                                                                                          facility,'' and
                                                                                          ``Stationary internal
                                                                                          combustion engine or
                                                                                          stationary
                                                                                          reciprocating internal
                                                                                          combustion engine.''
                                                                                          Adds new definitions
                                                                                          for the following
                                                                                          terms: ``Process
                                                                                          heater,'' ``Refinery
                                                                                          gas,'' ``Regenerative
                                                                                          cycle combustion
                                                                                          turbine,'' ``Simple
                                                                                          cycle combustion
                                                                                          turbine,'' and
                                                                                          ``Stationary
                                                                                          combustion turbine.''
 
----------------------------------------------------------------------------------------------------------------
                                                  * * * * * * *
                                       Chapter 129--Standards for Sources
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                                                  * * * * * * *
                         Additional RACT Requirements for Major Sources of NOX and VOCs
----------------------------------------------------------------------------------------------------------------
Section 129.96.................  Applicability.....         4/23/16  5/9/19, [insert     New section.
                                                                      Federal Register
                                                                      citation].
Section 129.97.................  Presumptive RACT           4/23/16  5/9/19, [insert     New section.
                                  requirements,                       Federal Register
                                  RACT emission                       citation].
                                  limitations, and
                                  petition for
                                  alternative
                                  compliance
                                  schedule.
Section 129.98.................  Facility-wide or           4/23/16  5/9/19, [insert     Conditionally approved.
                                  system-wide NOX                     Federal Register    See 40 CFR 52.2023(m).
                                  emissions                           citation].
                                  averaging plan
                                  general
                                  requirements.
Section 129.99.................  Alternative RACT           4/23/16  5/9/19, [insert     Conditionally approved.
                                  proposal and                        Federal Register    See 40 CFR 52.2023(m).
                                  petition for                        citation].
                                  alternative
                                  compliance
                                  schedule.
Section 129.100................  Compliance                 4/23/16  5/9/19, [insert     New section.
                                  demonstration and                   Federal Register
                                  recordkeeping                       citation].
                                  requirements.

[[Page 20292]]

 
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

0
3. Section 52.2023 is amended by adding reserved paragraph (l) and 
adding paragraph (m) to read as follows:

Sec.  52.2023  Approval status.

* * * * *
    (m) EPA conditionally approves Pennsylvania's 25 Pa Code sections 
129.98 and 129.99 submitted on May 16, 2016 to address the reasonably 
available control technology (RACT) requirements under CAA sections 
182(b)(2)(C), 182(f), and 184 under the 1997 and 2008 8-hour ozone 
NAAQS. Pursuant to CAA section 110(k)(4), this conditional approval is 
based upon a September 26, 2017 letter from Pennsylvania to submit to 
EPA, no later than 12 months from EPA's final conditional approval, 
additional SIP revisions to address the deficiencies identified. The 
SIP revisions, to be submitted by Pennsylvania, include:
    (1) All facility-wide or system-wide averaging plans approved by 
PADEP under 25 Pa Code 129.98 including but not limited to any terms 
and conditions that ensure the enforceability of the averaging plan as 
a practical matter, and
    (2) All source-specific RACT determinations approved by PADEP under 
25 Pa Code 129.99, including any alternative compliance schedules 
approved under Sec. Sec.  129.97(k) and 129.99(i); the source-specific 
RACT determinations submitted to EPA for approval into the SIP shall 
include any terms and conditions that ensure the enforceability of the 
source-specific RACT emission limitation as a practical matter.
[FR Doc. 2019-09478 Filed 5-8-19; 8:45 am]
 BILLING CODE 6560-50-P