Air Plan Partial Disapproval and Partial Approval; Pennsylvania; Attainment Plan for the Indiana, Pennsylvania Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard, 50778-50785 [2022-17449]
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50778
Federal Register / Vol. 87, No. 159 / Thursday, August 18, 2022 / Rules and Regulations
Dated: August 13, 2022.
H.R. Mattern,
Captain, U.S. Coast Guard, Captain of the
Port Sector Ohio Valley.
[FR Doc. 2022–17804 Filed 8–17–22; 8:45 am]
BILLING CODE 9110–04–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R03–OAR–2017–0615; FRL–9607–02–
R3]
Air Plan Partial Disapproval and Partial
Approval; Pennsylvania; Attainment
Plan for the Indiana, Pennsylvania
Nonattainment Area for the 2010 Sulfur
Dioxide Primary National Ambient Air
Quality Standard
Environmental Protection
Agency (EPA).
ACTION: Final rule.
AGENCY:
The Environmental Protection
Agency (EPA) is revising its prior action
that erroneously fully approved a state
implementation plan (SIP) revision
submitted by the Commonwealth of
Pennsylvania (PA), through the
Pennsylvania Department of
Environmental Protection (PADEP), to
EPA on October 11, 2017, and
supplemented on February 5, 2020. The
SIP revision provided a plan for
attainment of the 2010 sulfur dioxide
(SO2) primary national ambient air
quality standard (NAAQS) in the
Indiana, Pennsylvania SO2
nonattainment area (hereafter referred to
as the ‘‘Indiana, PA NAA’’ or ‘‘Indiana
Area’’). The attainment plan submission
included a base year emissions
inventory, an analysis of the reasonably
available control technology (RACT)
and reasonably available control
measure (RACM) requirements,
enforceable emission limitations and
control measures, a reasonable further
progress (RFP) plan, a modeling
demonstration of SO2 attainment, and
contingency measures for the Indiana
Area. EPA is revising its prior action
and is partially approving and partially
disapproving the SIP. This action is
being taken under the Clean Air Act
(CAA).
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SUMMARY:
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 www.regulations.gov,
or please contact the person identified
in the FOR FURTHER INFORMATION
CONTACT section for additional
availability information.
FOR FURTHER INFORMATION CONTACT:
Megan Goold, Planning &
Implementation Branch (3AD30), Air &
Radiation Division, U.S. Environmental
Protection Agency, Region III, Four
Penn Center, 1600 John F. Kennedy
Boulevard, Philadelphia, Pennsylvania
19103. The telephone number is (215)
814–2027. Ms. Goold can also be
reached via electronic mail at
goold.megan@epa.gov.
SUPPLEMENTARY INFORMATION:
I. Background
On March 17, 2022 (87 FR 15166),
EPA published a notice of proposed
rulemaking (NPRM) for the
Commonwealth of Pennsylvania. In the
NPRM, EPA provided notice to the
Commonwealth and the public and
described the basis for its determination
that it had erroneously fully approved
the Indiana, PA SO2 Attainment Plan,
and proposed to revise its formal
approval of the Plan to a partial
disapproval and partial approval. See
CAA section 110(k)(6). The formal SIP
revision was originally submitted by
Pennsylvania on October 11, 2017, and
later supplemented on February 5, 2020.
EPA took final action approving this
attainment plan on October 19, 2020 (85
FR 66240).
On December 18, 2020, the Sierra
Club, Clean Air Council, and
PennFuture filed a petition for judicial
review with the U.S. Court of Appeals
for the Third Circuit, challenging that
final approval.1 On April 5, 2021, EPA
filed a motion for voluntary remand
without vacatur of its approval of the
Indiana, PA SO2 attainment plan. On
August 17, 2021, the U.S. Court of
Appeals for the Third Circuit granted
EPA’s request for remand without
DATES: This final rule is effective on
vacatur of the final approval of
September 19, 2022.
Pennsylvania’s SO2 attainment plan for
ADDRESSES: EPA has established a
the Indiana, PA NAA, and required that
docket for this action under Docket ID
EPA take final action in response to the
Number EPA–R03–OAR–2017–0615. All remand no later than one year from the
documents in the docket are listed on
date of the court’s order (i.e., by August
the www.regulations.gov website.
Although listed in the index, some
1 Sierra Club, et. al v. EPA, Case No. 20–3568 (3rd
Cir.).
information is not publicly available,
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17, 2022). This action finalizes EPA’s
response to the court’s order.
II. Summary of SIP Revision and EPA
Analysis
In accordance with section 172(c) of
the CAA, the Pennsylvania attainment
plan for the Indiana Area includes an
emissions inventory for SO2 for the
plan’s base year (2011) and an
attainment demonstration. The
attainment demonstration includes the
following: (1) analyses that locate,
identify, and quantify sources of
emissions contributing to violations of
the 2010 SO2 NAAQS; (2) a
determination that the control strategy
for the primary SO2 sources within the
nonattainment areas constitutes RACM/
RACT; (3) a dispersion modeling
analysis of an emissions control strategy
for the primary SO2 sources contributing
to SO2 concentrations in the Area
(Keystone, Conemaugh, Homer City, and
Seward) purporting to show attainment
of the SO2 NAAQS by the October 4,
2018, attainment date; (4) requirements
for RFP toward attaining the SO2
NAAQS in the Area; (5) contingency
measures; (6) the assertion that
Pennsylvania’s existing SIP-approved
new source review (NSR) program meets
the applicable requirements for SO2;
and (7) the request that emission
limitations and compliance parameters
for Keystone, Conemaugh, Homer City,
and Seward be incorporated into the
SIP.
On February 5, 2020, in response to
comments submitting during the
proposal’s public comment period,
PADEP submitted supplemental
information in support of the attainment
plan. The February 5, 2020 submittal
included: (1) a supplemental air
dispersion modeling report; (2)
supplemental air dispersion modeling
data; (3) a supplemental air dispersion
modeling protocol; (4) a meteorological
monitoring plan; (5) meteorological
monitoring data; (6) meteorological
monitoring quality assurance, quality
control, and audit reports; (7) Clean Air
Markets Division (CAMD) emissions
data for 2010–2018; and (8) Continuous
Emissions Monitoring (CEM) data for
2010 through the third quarter of 2019.
The supplemental air dispersion
modeling used a more refined model
receptor grid than that in the original
submittal, meteorological data collected
near the controlling modeled source
(Seward), and more recent (2016–18)
background concentrations from the
South Fayette SO2 monitor (the monitor
used to determine background
concentrations in the original modeling
analysis). In order to allow for public
comment on this supplemental
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information and modeling, on March 9,
2020 (85 FR 13602), EPA published a
notice of data availability (NODA) for
the February 5, 2020, submittal.
EPA now has determined that it was
in error to fully approve the Indiana, PA
SO2 attainment plan, and is revising and
correcting its prior action in the same
manner as the prior full approval
without further submission from the
Commonwealth. See CAA section
110(k)(6). EPA is retaining the approval
of the emissions inventory and
nonattainment new source review
(NNSR) program requirements, and is
finalizing disapproval of the attainment
demonstration, RACM/RACT
requirements, RFP requirements, and
contingency measures.
Other specific requirements of section
172(c) and the rationale for EPA’s
proposed and final action are explained
in the NPRM, and its associated
technical support document (TSD), and
will not be restated here.
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III. EPA’s Response to Comments
Received
EPA received two sets of comments
on the notice of proposed rulemaking
for this action. A summary of the
comments and EPA’s responses are
provided below. To view the full set of
comments, refer to the docket for this
action, Docket EPA–R03–OAR–2017–
0615.
Comment 1: The commenter disagrees
that the SIP did not include an
assessment showing that the longer-term
average limits for Keystone and Seward
are of comparable stringency to the onehour Critical Emissions Value (CEV).
The commenter believes that Appendix
C of EPA’s 2014 Guidance for 1-hour
SO2 Nonattainment Area SIP
Submissions 2 (‘‘2014 Guidance’’) is a
statistical approach and is a surrogate
approach that was justified by
Appendix B, such that Appendix C is a
theorem and Appendix B is the proof.
The commenter states that the
Randomly Reassigned Emissions (RRE)
modeling approach provides a very
robust demonstration of a comparably
stringent relationship between the
modeling results of the CEV analysis
and the RRE analysis. The commenter
believes the facts below support that the
longer-term average limits have been
shown to be comparably stringent to the
one-hour CEV, and that the RRE
modeling is thorough in testing the
2 EPA Guidance for 1-hour SO Nonattainment
2
Area SIP Submissions, April 23, 2014,
www.epa.gov/sites/default/files/2016-06/
documents/20140423guidance_nonattainment_
sip.pdf.
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emissions distributions that had the
following attributes:
1. The emissions used in the RRE
modeling followed Appendix C of the
2014 Guidance because they reflected
the distribution of emissions expected
once the attainment plan had been
implemented.
2. High emission events were
modeled in a way that is representative
of both the variability shown by the
2016 emissions data and of the expected
distribution of emissions occurring in
compliance with the allowable longerterm average emissions limits.
3. High emission events (i.e., hours
with emissions above the CEV) were
randomly placed throughout the year in
the modeling in order to examine
combinations of high emissions and
varying meteorology.
4. Each of the 100 runs resulted in
modeled design values below the
NAAQS, which the commenter asserts
is a stringent requirement that is
equivalently stringent to the modeling
results for the one-hour CEV analysis,
which has the same modeling outcome.
Therefore, the commenter asserts that
Pennsylvania’s RRE modeling did
incorporate the necessary steps to
establish the comparably stringent
relationship between a modeled onehour CEV and the longer-term average
limits.
The commenter also asserts that the
fact that its RRE modeling approach—
which EPA used in Appendix B to test
the statistical adjustment approach in
Appendix C—results in different longerterm average limits than the Appendix
C approach in this specific case, is not
contrary to the 2014 Guidance because
they both demonstrate attainment. They
argue that the direct use of the
submitted modeling approach can be
viewed as the gold standard, with a very
high level of confidence that the
emissions distribution is protective of
the NAAQS.
The commenter also claims that
Appendix B uses an emissions
distribution that is expected once the
plan is in place, which is the same type
of emissions data used in the Appendix
C approach. The commenter continues
that EPA’s guidance does not require the
use of the 99th percentile of historic
hourly data in the future emissions
profile.
The commenter is also concerned that
EPA is requiring a clear link between
the modeled one-hour CEV and the
longer-term average emission limits
even though the words ‘‘clear’’ and
‘‘link’’ do not appear in the 2014
Guidance document. Although the
commenter disagrees with the
requirement to demonstrate a clear link
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between the modeled 1-hr CEV and the
longer-term average limits, and with
EPA’s position that its modeled future
emissions scenarios must represent the
worst case emissions scenarios
permissible under the limit, the
commenter believes that the RRE
modeling has satisfied those
requirements because, (1) the CEV was
used as one of the bins in the modeling,
thus demonstrating a clear link in the
commenter’s view, and (2) based on the
commenter’s comparison of modeled
emissions (future expected emissions),
and actual emissions from 2017–2021
for Keystone and Seward, the sources
have actually had a fewer number of
hours above the CEV than was modeled,
and there have been no observed onehour emissions from either source
equaling or exceeding the highest
hourly emissions used in the peak
modeled emissions bin.
The commenter continues that
discount factors were calculated from
the RRE modeling of 0.989 for Keystone
and 0.686 for Seward, which are
consistent with the range of the
discount values listed in Appendix D.
Response 1: In general, the
commenter is misinterpreting the 2014
Guidance and conflating the use of
Appendix B of the guidance as an
apparent alternate method of satisfying
the SIP requirements. A SIP requires
that the plan provide for attainment of
the NAAQS. Attainment of the NAAQS
is successfully demonstrated when the
affected sources operate within the
limits in the plan such that emissions
from any and all variable operating
scenarios are in compliance with those
limits and do not lead to NAAQS
violations. Modeling the maximum onehour emission rate (i.e., the maximum
allowable rate or ‘worst-case’) that
yields a design concentration below the
NAAQS is the means by which the SIP
provides for attainment. So, a one-hour
limit is the mechanism for providing for
attainment in the SIP. In the alternative
to the one-hour limit, the 2014
Guidance provides flexibility for
developing limits with longer-term
averages (up to 30-days). Appendix C
describes the method to develop longerterm limits that are comparably
stringent to the maximum one-hour
limit. Appendix C uses the 99th
percentile distribution of emissions to
ensure that the longer-term limits are
appropriately adjusted to be comparably
stringent, and by extension, provide for
attainment. Appendix B is merely a
diagnostic tool using a statistical
example as a back check to demonstrate
that the 99th percentile consideration
used in Appendix C is the appropriate
means to show comparable stringency.
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Appendix B is not a tool which can be
decoupled from Appendix C to develop
limits sufficient to provide for
attainment. Accordingly, the state SIP
cannot be said to provide for attainment
because the longer-term limits have not
been shown to be comparably stringent
to the one-hour maximum allowable
value. The worst case emissions
scenario has not been simulated (for
example by a 99th percentile evaluation
of the emission distribution), and
therefore the RRE analysis does not
demonstrate that the longer-term limit
that the commenter claims is proven by
the RRE analysis will provide for
attainment actually does so, when it was
performed by modeling future expected
operating scenarios that did not
simulate worst case conditions. Using
Appendix B as a standalone tool to
develop emission limits, as the state has
done here, is not appropriate without
considering worst case emissions,
which is accomplished by linking to the
CEV as is reflected in Appendix C. The
variable emissions modeling approach
used by the state provides no direct
means of assessing whether any
particular long-term limit is of
comparable stringency to any particular
one-hour limit.
The 2014 Guidance did not remove
the requirement for an attainment
demonstration to be based on maximum
allowable emissions (as the commenter
implies), nor did it recommend basing
attainment modeling on an expected
hourly distribution of emissions once
the attainment plan had been
implemented (as the commenter
implies). The 2014 Guidance stated that
‘‘for SO2 modeling, maximum allowable
emissions are the basis of the emissions
input to the model in accordance with
Section 8 of Appendix W and past SO2
guidance (U.S. EPA, 1994).’’ (2014
Guidance, pg. A–5). Furthermore, the
Guidance used the term critical
emission value to refer to the hourly
emission rate that the model predicts
would result in the 5-year average of the
annual 99th percentile of daily
maximum hourly SO2 concentrations at
the level of the one-hour NAAQS, given
representative meteorological data for
the area. (2014 Guidance, pg. 23). The
guidance provided a methodology by
which the maximum allowable modeled
hourly emissions CEV would be clearly
linked to the comparably stringent
longer-term average limit. While the
terms ‘‘clear’’ and ‘‘link’’ are not
included in the guidance document, the
methods set forth in Appendix C
describe a step-by-step process by
which an adjustment factor can be
calculated, which would then be
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directly applied to the CEV to create a
comparably stringent longer-term
average limit. Consequently, if the CEV
changed, the comparably stringent
longer-term limit would also change as
a result of the application of the
adjustment factor.
Regardless of whether the guidance
document uses the words ‘clear’ and
‘link,’ the absence of a direct showing
that the limits in Pennsylvania’s SIP are
comparably stringent to the one-hour
limits modeled as necessary to provide
for attainment means that the plan
presumptively does not provide
adequate assurance of attainment.
Further, the commenter does not make
a consistent argument that long-term
limits may be justified by modeling a
significantly different level of emissions
(i.e., not maximum allowable emissions)
than the emissions that must be
modeled to determine one-hour limits.
Additionally, the adjustment factor as
specified in the 2014 Guidance is
derived from a statistical analysis of a
set of data that reflect the emissions
variability that the controlled source is
expected to exhibit. Specifically, the
adjustment factor is calculated by
comparing the 99th percentile of hourly
emissions data (from the previously
described data set) compared to the 99th
percentile of the longer-term averaging
period values. This comparison at the
higher end of the distribution (99th
percentile) of data values is purposeful
because ‘‘the goal of the analyses is to
identify a longer-term average limit that
requires a comparable degree of control,
particularly at times of greatest
emissions as would be required by the
1-hr limit that would otherwise be set,
the EPA would expect the analyses to
compare the corresponding longer-term
average and the 1-hr values among times
of greatest emissions’’ (2014 Guidance,
pg. 29). Without undertaking this
comparison, EPA does not believe it is
able to determine that a longer-term
average limit is comparably stringent to
the one-hour limit that would otherwise
be necessary to demonstrate attainment
of the one-hour NAAQS. The state’s
plan has not evaluated how the modeled
emissions compare to worst case
emissions that are allowable under the
long-term limits, either in terms of
whether the SIP modeled the maximum
allowable emissions or in terms of
whether a worst case distribution of
emissions was modeled. Therefore, EPA
does not have evidence that the
modeled emissions was a conservative
distribution of emissions in relation to
the relevant benchmark of worst case
allowable emissions.
EPA does not agree that the RRE
modeling provided this necessary type
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of comparably stringent analysis. First,
as the commenter points out, although
the CEV was used as one of the bins of
hourly emission values in the modeling,
the state’s longer-term limit was not
based on that CEV such that if the CEV
changed the longer-term limit would in
turn change in the same direction. As
noted in the proposal for this rule, in
the supplemental modeling analysis
Pennsylvania submitted for Seward,
when Seward’s CEV decreased by 579
pounds per hour (lb/hr) (from 5,079 lb/
hr to 4,500 lb/hr), the longer-term limit
derived by Pennsylvania from the RRE
modeling remained unchanged. The air
quality found by modeling of variable
emissions is a function of the full range
of modeled emissions, influenced by the
frequency and magnitude of emission
values in all parts of the distribution,
and so the use of the CEV as one of the
bin values provides almost no assurance
that the full RRE modeling analysis
which includes other binned emissions
is linked in any meaningful way to the
CEV.
Additionally, the RRE approach used
the entire distribution of past annual
hourly emissions to set a longer-term
average limit, rather than the 99th
percentile of annual hourly emissions,
which does not satisfy EPA’s
recommendation to use the time of
greatest emissions, and thus fails the
Appendix C test for comparable
stringency (2014 Guidance, pg. 29).
The commenter seems to be confused
about what values in the analysis need
to be comparably stringent; the
commenter claims that the modeling
results of the RRE modeling approach
are comparably stringent to the onehour CEV modeling because both show
design values below the NAAQS. The
values that need to be comparably
stringent are the CEV and the longerterm limit, not the modeled SO2 design
values.
The modeled design values are
dependent on the model inputs,
particularly the hourly emissions
modeled. While EPA recommended that
the ‘‘comparably stringent’’ assessment
be based on a set of emissions data that
can be expected to reflect the variability
of emissions once the subject source
implements its attainment plan, this
recommendation was in conjunction
with the recommendation to use the
times of greatest emissions (which the
Guidance suggests is properly simulated
by using the 99th percentile
distribution), and to begin the
comparably stringent analysis with the
CEV. The commenter seems to have
misconstrued these recommendations
and incorrectly concluded that
modeling an historic hourly distribution
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of emissions for a source in an
attainment modeling demonstration
could be used as a substitute to
modeling maximum allowable
emissions, or to determining the CEV
and then adjusting that value to
calculate a comparably stringent longerterm limit. Pennsylvania’s RRE
modeling did not model maximum
allowable emissions, nor did it
demonstrate a relationship between the
CEV (maximum allowable hourly
emission value) and the longer-term
average limit as recommended in EPA’s
2014 Guidance in order to enable a
conclusion that the longer-term limits
are comparably stringent to the onehour CEV.
Pennsylvania’s RRE analysis modeled
the entire distribution of historic hourly
emissions in 100 randomly assigned
model runs; and in the case for Seward,
it set the 30-day limit at the weighted
average of hourly emissions modeled,
and in the case for Keystone, it set the
24-hour limit at the longer-term value
that was modeled 30% of the year. It is
questionable whether either of these
longer-term average limits are actually
being tested in the RRE model runs, or
whether the model runs only test the
distribution of hourly emissions that
were modeled. EPA is not confident that
these RRE derived longer-term limits
will act as a constraint on the
distribution of future hourly emissions
to the same degree as the Appendix C
approach using the 99th percentile
value, and therefore EPA does not have
the same degree of confidence that the
NAAQS will not be violated. The future
hourly emissions distribution could
skew towards having more frequent
hourly values above or near the CEV, in
which case the RRE modeling
performed for these sources might not
show design values complying with the
NAAQS considering the modeling
results from the RRE modeling resulted
in design values extremely close to the
75 parts per billion (ppb) standard (as
discussed in more detail below).
Additionally, Pennsylvania’s use of a
limited number of emission bins with a
high emissions ‘‘floor’’ adds a further
disconnect from the real distribution of
worse case emissions.
Appendix B provided results of a
variety of emissions scenarios for a
suitably adjusted longer-term average
limit, which consistently resulted in
design values between 39 and 59 ppb.
EPA notes on page B–3 of the 2014
Guidance, ‘‘in each of these simulations
a substantial number of hours (on
average, just under one percent) had
emissions higher than the CEV.
Nevertheless, given the margin between
these values and the NAAQS level of 75
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ppb, this analysis indicates that the
likelihood of a violation occurring with
these emissions values is extremely
low.’’ The RRE modeling provided by
Pennsylvania in support of Seward’s 30day limit and Keystone’s 24-hour limit
resulted in design values just slightly
below the 75 ppb NAAQS, which
provides very little margin by which
hourly emissions could vary from those
modeled by Pennsylvania and not cause
a violation. If Pennsylvania had
properly accounted for worst case
emissions allowable under the limit, it
is quite possible that would have shown
a violation.
Combining the impacts of using the
99th percentile of emissions statistics,
and the large margin between the
resultant modeled concentration in
Appendix B and the level of the
NAAQS, EPA is confident that a longerterm average limit based on the
Appendix C methodology can be
protective of the NAAQS. In contrast,
the state has provided an RRE modeled
demonstration of expected future hourly
emissions, that when modeled, results
in design values that come near to
violating the NAAQS while also
reflecting compliance with the longerterm average limits but at emissions
scenarios not representative of worst
case emissions levels allowed under the
longer-term average limits. The State’s
submission does not provide confidence
that a comparably stringent relationship
(as the commenter claims) exists and
therefore, does not provide a sufficient
level of assurance that the longer-term
average limits provide for NAAQS
attainment.
In support of its claim that the RRE
modeling demonstrated attainment
using worst case emission scenarios, the
commenter provided an analysis which
purportedly showed that more recent
emissions (2017–2021) had less hours
above the CEV than the hourly
emissions modeled for Seward and
Keystone. However, no evidence was
provided that the distribution of hourly
emissions modeled by the RRE runs
were comparable to the worst-case
hourly emissions scenario that could
occur in compliance with the longerterm emission limit. The commenter’s
comparison of binned hourly emissions
values modeled to those that actually
occurred throughout recent years, does
not provide evidence of worst case
hourly emissions scenarios for a onehour NAAQS. In contrast, a different
commenter provided modeling of
Keystone’s actual emissions from 2019–
2021, which purportedly showed that
modeled NAAQS violations occurred
when the source was in compliance
with the 24-hour limit of 9600 lb/hr,
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and that the source’s hourly emissions
exceeded the CEV during 35 hours in
2019, 69 hours in 2020, and 232 hours
in 2021. This modeling analysis
demonstrates that when a different
emissions scenario is modeled from
Pennsylvania’s RRE modeling, a
NAAQS violation occurs, highlighting
the importance of modeling worst case
emissions to ensure attainment.
The RRE modeling approach used by
Pennsylvania did not reflect the
maximum possible emissions that could
occur while maintaining compliance
with the longer-term average emission
limit, nor did the approach provide a
comparably stringent analysis.
Consequently, it was erroneous for EPA
to fully approve the Indiana, PA SO2
Attainment Plan in 2020, and it is
necessary for EPA to correct its error by
revising its action to partially approve
and partially disapprove the Plan.
Comment 2: The commenter notes
that the monitors do not show evidence
of nonattainment, and noted that, even
though the Strongstown monitor is not
located in the area of the modeled
maximum SO2 concentration, previous
modeling demonstrated that the
Strongstown monitor would be
‘‘significantly impacted’’ if elevated
impacts occurred elsewhere in the
Indiana, PA NAA. The commenter
provided data from the Strongstown
monitor showing that its monitored
values are decreasing and approaching
values from the background monitor in
South Fayette.
Response 2: EPA agrees that the
monitors in Strongstown and South
Fayette are reading below the standard.
However, as noted by the commenter,
the monitors are not located in the area
of modeled maximum concentrations
and therefore are not, by themselves,
indicative of whether the area is
meeting the SO2 NAAQS. Although the
comment makes reference to the
‘‘modeling effort,’’ it is not clear what
modeling the commenter is referring to
and the commenter has not provided
any other data to support the claim that
the Strongstown monitor would be
‘‘significantly impacted’’ if elevated
impacts occurred elsewhere in Indiana,
PA.
SO2 concentrations result from direct
emissions from combustion sources so
that concentrations are highest
relatively close to sources and are much
lower at greater distances due to
dispersion, i.e., a strong concentration
gradient. Given the source-oriented
nature of this pollutant (see 75 FR at
35570, June 22, 2010), dispersion
models are the most appropriate air
quality modeling tools to predict the
near field concentrations and gradients
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of this pollutant. EPA has received
dispersion modeling from a different
commenter that purportedly shows
modeled violations within the Indiana,
PA NAA near the Indiana and
Armstrong County border, using actual
2019–2021 emissions for Keystone,
while the source was purportedly
complying with the 24-hour limit of
9,600 lb/hr. Consequently, EPA does not
regard the commenter’s observations
about the Strongstown monitor as
providing persuasive evidence that the
Area is not violating the NAAQS or that
the Plan provides for attainment of the
NAAQS.
Comment 3: The commenter claims
that EPA is acting inconsistently
because EPA approved the use of an
alternative modeling method in Miami,
AZ, which used Appendix C to
calculate an adjustment factor, and
included a supporting Appendix B
modeling demonstration, which the
commenter claims ‘‘definitively’’
confirmed the adequacy of the
Appendix C calculated adjustment
factor. The commenter argues that
Appendix B was used as an essential
component of the SIP because Appendix
C was used in an application not
addressed in EPA’s 2014 Guidance.
Further, the commenter argues that the
regulatory requirement is attainment of
the NAAQS. The commenter alleges that
this disapproval is arbitrary and
capricious because it proposes to
interpret the guidance differently in two
nonattainment areas and apply it
inconsistently without any explanation
for the inconsistency.
Response 3: EPA disagrees that it has
applied the 2014 Guidance
inconsistently between the Indiana, PA
attainment plan and the Miami, AZ
attainment plan. As the commenter
noted, a significant difference between
the two plans is that the Arizona plan
used the Appendix C methodology to
calculate a comparably stringent longerterm average limit, and then provided
additional modeling to analyze whether
the longer-term emission limit derived
using Appendix C was reasonably likely
to be protective of the NAAQS. In
contrast, Pennsylvania used RRE
modeling to arrive at the longer-term
average limit without demonstrating
comparable stringency to the one-hour
CEV. The Arizona longer-term limit was
calculated by obtaining a ratio of the
99th percentile of hourly emissions
compared to the 99th percentile of
longer-term average values as
recommended by EPA. This ratio or
adjustment factor was then applied to
the CEV, thus taking into account the
times of greatest emissions and linking
the longer-term limit to the maximum
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modeled emission value (CEV),
accordingly. Although the Arizona plan
included an RRE-type (i.e., Appendix B)
assessment of projected air quality, EPA
did not rely on that assessment and
made no reference to it in its final rule,
insofar as the SIP was approvable
without regard to the merits of the
assessment.
In contrast, the longer-term limits for
Keystone and Seward in the Indiana, PA
attainment plan were developed using
only RRE modeling, which modeled the
entire distribution of historic hourly
emissions and based the limit on the 24hour values that were modeled 30% of
the time (Keystone) and the weighted
annual average (Seward), neither of
which considered the 99th percentile
statistics of the historic hourly data set
(times of greatest emissions), and
neither of which were linked to the
maximum modeled hourly emission rate
(CEV). While sources can use
approaches other than Appendix C to
derive a longer-term average limit, the
evidence that the other approach will
result in attainment needs to be as
compelling. EPA believes that any
approach used should begin with the
CEV, and account for times of greatest
emissions in setting a longer-term limit.
EPA also has noted that supplemental
limits may be necessary to further
constrain the frequency and magnitude
of these worst case emission episodes.
Due to these clear differences in
approaches, EPA is not acting
inconsistently in our actions on the
Indiana, PA and Miami, AZ attainment
plans as the commenter claims; rather,
EPA is applying the 2014 Guidance
consistently across rather dissimilar
situations.
Comment 4: The commenter claims
that EPA’s action is arbitrary and
capricious because the disapproval is
not based on a rational connection
between the facts found and the choice
made. The commenter asserts that the
facts in the record show that Appendix
B is the proof of the statistical analysis
in Appendix C, and that using the
Appendix B approach is a more robust,
thorough way to show that a longer-term
emission limit can be protective of the
NAAQS. The commenter claims that the
use of the Appendix B approach is
consistent with EPA’s requirements for
an approvable SIP: ‘‘. . . as the EPA
explained in our 2014 SO2 Guidance
and in numerous proposed and final SIP
actions implementing the SO2 NAAQS,
a key element of an approvable SIP is
the required modeling demonstration
showing that the remedial control
measures and strategy are adequate to
bring a previously or currently violating
area into attainment.’’ 84 FR 8815,
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March 12, 2019. EPA is now seemingly
self-contradictory and believes that
Appendix B does not provide a longerterm emission limit that is equivalently
stringent to the one-hour limit. Nothing
in the record supports making this
determination, the commenter claims.
Response 4: EPA disagrees with the
commenter and believes the commenter
has misunderstood the purpose of
Appendix B of the 2014 Guidance. First,
the EPA language quoted by the
commenter is referring to the modeling
performed to determine the CEV, which
is a one-hour limit for SO2 emissions,
rather than a longer-term limit. Also, as
noted in the 2014 Guidance, ‘‘Appendix
B documents analyses that the EPA has
conducted to evaluate the extent to
which longer-term limits that have been
adjusted to have comparable stringency
to one-hour limits as the critical
emissions value provide for
attainment.’’ (pg. 25). Also, as noted in
the Guidance, ‘‘at issue is the likelihood
that a source complying with a 30-day
average limit reflecting the adjustment
generally recommended in this
guidance [emphasis added] would have
sufficiently high emissions on a
sufficient fraction of the potential
exceedance days to cause an SO2
NAAQS violation.’’ (pg. B–2). In each of
the modeling simulations run by EPA in
support of the Appendix C
methodology, the estimated design
values obtained were between 39 and 58
ppb, and thus EPA stated, ‘‘Given the
margin between these values and the
NAAQS level of 75 ppb, this analysis
indicates that the likelihood of a
violation occurring with these emissions
values is extremely low.’’ (pg. B–3).
Thus, the modeling exercise was
conducted as a test on emission limits
that were considered comparably
stringent with the CEV (i.e., comparably
stringent longer-term emission limits,
and not simply ‘‘longer-term’’ emission
limits); it was not used to develop the
comparably stringent longer-term limits
because, as noted, the results of the
Appendix B analyses yielded a range of
estimated design values and EPA did
not select a specific modeling scenario
result to rely upon as an attainment
demonstration. Rather, EPA used the
analysis as support that the comparably
stringent longer-term limit derived
using the Appendix C methodology,
notwithstanding infrequent hourly
emissions spikes above the CEV, could
nevertheless protect the NAAQS.
The commenter’s claim that
Appendix B is a ‘‘proof’’ of the
statistical analysis in Appendix C is not
substantiated. A mathematical proof of
a theorem should show that the theorem
holds true at all times so long as any
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constraints set forth by the theorem are
followed (e.g., theorem only applies to
prime numbers). In Appendix B, EPA
summarizes modeling exercises that
were conducted using the emission
patterns that could be expected even
when a source is just barely complying
with a long-term average emission limit.
(2014 Guidance, at B–4). Based on this,
EPA concluded that these analyses
indicated ‘‘that suitably adjusted longerterm average limits can generally be
expected to provide adequate
confidence that the attainment plan will
provide for attainment.’’ (pg. B–2).
Words such as ‘‘generally’’ and
‘‘adequate confidence’’ are not words
used to describe a mathematical proof.
The modeling analyses were one
piece of evidence that provided more
confidence to EPA that a comparably
stringent longer-term limit (set using the
99th percentile of emissions statistics)
can be protective of a one-hour NAAQS,
but the Appendix B modeling analyses
did not ‘‘prove’’ that a longer-term limit
set via other methods that went through
100 model runs with a specified hourly
emissions distribution and that modeled
attainment would provide the same
level of confidence that the limit is
protective of the one-hour NAAQS.
More specifically, Pennsylvania
modeled hourly values that, when
averaged over a 24-hour day, equaled
less than the 24-hour limit for 70% of
the year for Keystone. That is, while the
24-hour limit for Keystone was set at
9,600 lb/hr, the hourly emissions that
were modeled averaged between 5,000
and 8,964 lb/hr on a 24-hour basis for
70% of the year; and the hourly
emissions that were modeled averaged
9,600 lb/hr on a 24-hour basis for 30%
of the year. Pennsylvania did not scale
the data set such that the modeled
hourly values resulted in 24-hour
averages that just met the 24-hour limit
of 9,600 lb/hr. Therefore, it’s
questionable whether the RRE modeling
actually tested the 24-hour limit for
Keystone. If the 24-hour averaged
emissions varied from those that were
modeled, such that 50% or 100% of the
24-hour averages equaled 9,600 lb/hr
(the limit) rather than only 30%, it is
uncertain that the modeled
concentrations would still result in
attainment. On the other hand, EPA’s
methods for determining a comparably
stringent limit do provide confidence
that changes in the hourly emissions
distribution while in compliance with
the longer-term limit will still provide
for attainment. Tellingly, at no point
does the guidance recommend use of
the methods described in Appendix B as
a means of determining suitable limits
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or of determining whether limits
determined by other means (whether of
comparable stringency to a one-hour
limit at the CEV or not) will suitably
provide for attainment. Thus,
characterizing Appendix B as ‘proof’ of
the Appendix C theorem is off base.
Comment 5: A different commenter
claims that longer-term limits are
fundamentally incapable of protecting a
one-hour NAAQS. The commenter
provided an updated analysis of
Keystone’s actual hourly emissions for
the years 2018 through 2021 which
showed that the source exceeded the
CEV over 500 hours. The commenter
noted that 2021 was worse than 2020.
The analysis also showed that Seward
exceeded the CEV 71 times in that same
period (4 years). The commenter
believes that the NAAQS will not be
attained if just four hours on four days
have ambient concentrations above 75
ppb, and thus concludes that longerterm emissions averaging cannot protect
the NAAQS. The commenter therefore
asserts that the current emission limits
in the SIP for Keystone and Seward are
inadequate to protect air quality.
In addition, the commenter calculated
a conversion factor for Keystone using
Appendix C and the more recent 2018–
2021 hourly emissions data and noted
the analysis yields a limit of 8,292.5 lb/
hr (24-hour daily average), which is
below the current limit of 9,600 lb/hr as
a 24-hour daily average.
Response 5: EPA disagrees with the
commenter’s assertion that a longerterm limit, so long as it is properly set,
cannot protect a one-hour NAAQS. But
that abstract issue is not being decided
in this action. In this case, EPA agrees
with the commenter that the specific
longer-term limits for Keystone and
Seward were not set at a level that
ensures the protection of the one-hour
SO2 NAAQS, since they were not shown
to be comparably stringent to a modeled
attaining one-hour CEV. EPA agrees
with the commenter that the longer-term
limits for Keystone and Seward do not
ensure protection of the NAAQS, and
with this action will finalize
disapproval of the attainment
demonstration.
Comment 6: The commenter provided
recent air quality modeling allegedly
demonstrating that SO2 emissions from
Keystone, Conemaugh, and Seward
continue to cause nonattainment in
Pennsylvania, both inside and outside
the Indiana NAA. The air quality
modeling submitted with the comment,
which used actual emissions from
Keystone from 2019 through 2021,
purportedly demonstrates that Keystone
is causing violations of the NAAQS
(209.9 micrograms per cubic meter (mg/
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50783
m3)). The commenter also provided
annual SO2 emissions for Keystone,
which show lower annual emissions in
2020 (13,011 tons per year), but other
years range from 17,000–24,000 tons per
year. Using actual emissions for various
three-year time periods from 2015–2017
through 2019–2021, the commenter
provided modeling demonstrating that
Seward and Conemaugh cause
violations of the NAAQS (244.6 mg/m3–
275.4 mg/m3) 3 outside the
nonattainment area.
Response 6: EPA believes that this
final rule may result in Pennsylvania
adopting tighter SO2 emission limits for
both Keystone and Seward which will
reduce their hourly emissions and better
provide for reductions in SO2
concentrations towards achieving
attainment of the NAAQS, subject to
EPA’s evaluation of any such future
limits.
Regarding the commenter’s modeling,
which seems to show modeled SO2
NAAQS violations in Westmoreland
and Cambria counties in Pennsylvania
outside the boundaries of the Indiana
NAA, EPA notes that it is not basing its
partial disapproval of the Indiana
attainment plan on these modeled
NAAQS violations outside of the
Indiana NAA. As stated in the proposal
for this action, EPA is planning a
separate regulatory action under the
Clean Air Act to address those modeled
NAAQS violations.
Comment 7: The commenter states
that Conemaugh and Seward’s SO2
pollution implicates serious
environmental justice (EJ) concerns. The
commenter provided an EJ Screen
analysis which indicates that southeast
of Seward the population is
characterized by low incomes and
generally elderly population. The
commenter also overlaid the modeled
violations of the NAAQS with the EJ
screen map showing that the modeled
violations are impacting the identified
vulnerable population. The commenter
asserts that this adds urgency to the
need for attainment to be achieved and
SO2 emissions from Conemaugh and
Seward to be properly limited.
Response 7: EPA’s analysis in the
notice of proposed rulemaking showed
similar results to the commenter’s EJ
screen analysis and indicated
communities with environmental justice
concerns both inside and outside the
Indiana nonattainment area. EPA
therefore encourages Pennsylvania to be
as expeditious as practicable in
3 In the Round 3 intended designations (82 FR
41903) published September 5, 2017, EPA endorsed
a value of 196.4 mg/m3 (based on calculations using
all available significant figures) as equivalent to 75
ppb.
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developing its new attainment plan
limits in order to address the emissions
impact on the vulnerable populations
both inside the current nonattainment
area, and in adjacent areas.
IV. Final Action
EPA is partially approving and
partially disapproving the Indiana, PA
attainment plan as a correction of its
erroneous prior full approval action and
as a revision to the Pennsylvania SIP.
See CAA section 110(k)(6). Specifically,
EPA is disapproving the attainment
demonstration, RACT/RACM
determination, RFP requirements, and
contingency measures. EPA is retaining
the approval of the emissions inventory
and the NNSR program.
This action initiates a sanctions clock
under CAA section 179, providing for
emission offset sanctions for new
sources if EPA has not fully approved a
revised SIP attainment plan within 18
months after final partial disapproval,
and providing for highway funding
sanctions if EPA has not fully approved
a revised plan within 6 months
thereafter. The sanctions clock can be
stopped only if the conditions of EPA’s
regulations at 40 CFR 52.31 are met.
This action also initiates an obligation
for EPA to promulgate a Federal
implementation plan within 24 months
unless Pennsylvania has submitted, and
EPA has fully approved, a plan
addressing these attainment planning
requirements.
V. Statutory and Executive Order
Reviews
Additional information about these
statutes and Executive Orders can be
found at www.epa.gov/laws-regulations/
laws-and-executive-orders.
A. Executive Order 12866: Regulatory
Planning and Review and Executive
Order 13563: Improving Regulation and
Regulatory Review
This action is not a significant
regulatory action and was therefore not
submitted to the Office of Management
and Budget (OMB) for review.
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B. Paperwork Reduction Act (PRA)
This action does not impose an
information collection burden under the
PRA, because this SIP partial approval
and partial disapproval does not in-andof itself create any new information
collection burdens, but simply partially
approves and partially disapproves
certain State requirements for inclusion
in the SIP.
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C. Regulatory Flexibility Act (RFA)
I certify that this action will not have
a significant economic impact on a
substantial number of small entities
under the RFA. This action will not
impose any requirements on small
entities. This SIP partial approval and
partial disapproval does not in-and-of
itself create any new requirements but
simply partially approves and partially
disapproves certain pre-existing State
requirements for inclusion in the SIP.
D. Unfunded Mandates Reform Act
(UMRA)
This action does not contain any
unfunded mandate as described in
UMRA, 2 U.S.C. 1531–1538, and does
not significantly or uniquely affect small
governments. This action does not
impose additional requirements beyond
those imposed by state law.
Accordingly, no additional costs to
state, local, or tribal governments, or to
the private sector, will result from this
action.
E. Executive Order 13132: Federalism
This action does not have federalism
implications. It will not have substantial
direct effects on the states, on the
relationship between the national
government and the states, or on the
distribution of power and
responsibilities among the various
levels of government.
F. Executive Order 13175: Coordination
With Indian Tribal Governments
This action does not have tribal
implications, as specified in Executive
Order 13175, because the SIP EPA is
disapproving would not apply on any
Indian reservation land or in any other
area where the EPA or an Indian tribe
has demonstrated that a tribe has
jurisdiction, and will not impose
substantial direct costs on tribal
governments or preempt tribal law.
Thus, Executive Order 13175 does not
apply to this action.
G. Executive Order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
The EPA interprets Executive Order
13045 as applying only to those
regulatory actions that concern
environmental health or safety risks that
the EPA has reason to believe may
disproportionately affect children, per
the definition of ‘‘covered regulatory
action’’ in section 2–202 of the
Executive order. This action is not
subject to Executive Order 13045
because this SIP partial approval and
partial disapproval does not in-and-of
itself create any new regulations, but
PO 00000
Frm 00022
Fmt 4700
Sfmt 4700
simply partially approves and partially
disapproves certain pre-existing State
requirements for inclusion in the SIP.
H. Executive Order 13211: Actions That
Significantly Affect Energy Supply,
Distribution, or Use
This action is not subject to Executive
Order 13211, because it is not a
significant regulatory action under
Executive Order 12866.
I. National Technology Transfer and
Advancement Act (NTTAA)
Section 12(d) of the NTTAA directs
the EPA to use voluntary consensus
standards in its regulatory activities
unless to do so would be inconsistent
with applicable law or otherwise
impractical. The EPA believes that this
action is not subject to the requirements
of section 12(d) of the NTTAA because
application of those requirements would
be inconsistent with the CAA.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations and
Low-Income Population
The EPA lacks the discretionary
authority to address environmental
justice in this rule.
K. Congressional Review Act (CRA)
This action is subject to the CRA, and
the EPA will submit a rule report to
each House of the Congress and to the
Comptroller General of the United
States. This action is not a ‘‘major rule’’
as defined by 5 U.S.C. 804(2).
L. 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 October 17, 2022. Filing a
petition for reconsideration by the
Administrator of this final rule does not
affect the finality of this rule 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
pertaining to the partial approval and
partial disapproval of the Indiana, PA
SO2 attainment plan, 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, Intergovernmental relations,
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Reporting and recordkeeping
requirements, Sulfur oxides.
PART 52—APPROVAL AND
PROMULGATION OF
IMPLEMENTATION PLANS
Adam Ortiz,
Regional Administrator, Region III.
1. The authority citation for part 52
continues to read as follows:
■
For the reasons stated in the
preamble, the EPA amends 40 CFR part
52 as follows:
Authority: 42 U.S.C. 7401 et seq.
Subpart NN—Pennsylvania
2. In § 52.2020, the table in paragraph
(e)(1) is amended by adding an entry
Name of nonregulatory SIP revision
Applicable geographic
area
*
Attainment Plan for the
Indiana, Pennsylvania Nonattainment
Area for the 2010
Sulfur Dioxide Primary National Ambient Air Quality
Standard.
*
Indiana County and
portions of Armstrong County
(Plumcreek Township, South Bend
Township, and
Elderton Borough).
*
*
*
*
*
4. Amend § 52.2033 by revising
paragraph (f) to read as follows:
■
§ 52.2033
Control strategy: Sulfur oxides.
*
*
*
*
(f) EPA partially approves and
partially disapproves the attainment
demonstration State Implementation
Plan for the Indiana, PA Sulfur Dioxide
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*
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State submittal date
Nonattainment Area submitted by the
Pennsylvania Department of
Environmental Protection on October
11, 2017 and updated on February 5,
2020, and corrected permits submitted
on May 13, 2020. EPA approves the base
year inventory and the Nonattainment
New Source Review (NNSR)
requirements, and disapproves the
attainment demonstration, Reasonably
Frm 00023
Fmt 4700
§ 52.2020
Sfmt 9990
Identification of plan.
*
*
(e) * * *
(1) * * *
EPA approval date
*
*
*
10/11/17,
8/18/22, [Insert FedSupplemental informaeral Register Citation submitted 02/
tion].
05/20, updated re10/19/20, 85 FR
dacted permits sub66255.
mitted on 05/13/20.
PO 00000
‘‘Attainment Plan for the Indiana,
Pennsylvania Nonattainment Area for
the 2010 Sulfur Dioxide Primary
National Ambient Air Quality
Standard’’ at the end of the table to read
as follows:
*
■
50785
*
*
Additional explanation
*
*
Partial Disapproval (attainment demonstration, Reasonably Available Control Technology (RACT)/Reasonably Available Control Measures (RACM) determination, Reasonable Further Progress (RFP) requirements, contingency measures) and Partial
Approval (emissions inventory and nonattainment new source review (NNSR)
program) 52.2033(f).
Available Control Technology (RACT)/
Reasonably Available Control Measures
(RACM) determination, Reasonable
Further Progress (RFP) requirements
and contingency measures.
[FR Doc. 2022–17449 Filed 8–17–22; 8:45 am]
BILLING CODE 6560–50–P
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Agencies
[Federal Register Volume 87, Number 159 (Thursday, August 18, 2022)]
[Rules and Regulations]
[Pages 50778-50785]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-17449]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R03-OAR-2017-0615; FRL-9607-02-R3]
Air Plan Partial Disapproval and Partial Approval; Pennsylvania;
Attainment Plan for the Indiana, Pennsylvania Nonattainment Area for
the 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is revising its
prior action that erroneously fully approved a state implementation
plan (SIP) revision submitted by the Commonwealth of Pennsylvania (PA),
through the Pennsylvania Department of Environmental Protection
(PADEP), to EPA on October 11, 2017, and supplemented on February 5,
2020. The SIP revision provided a plan for attainment of the 2010
sulfur dioxide (SO2) primary national ambient air quality
standard (NAAQS) in the Indiana, Pennsylvania SO2
nonattainment area (hereafter referred to as the ``Indiana, PA NAA'' or
``Indiana Area''). The attainment plan submission included a base year
emissions inventory, an analysis of the reasonably available control
technology (RACT) and reasonably available control measure (RACM)
requirements, enforceable emission limitations and control measures, a
reasonable further progress (RFP) plan, a modeling demonstration of
SO2 attainment, and contingency measures for the Indiana
Area. EPA is revising its prior action and is partially approving and
partially disapproving the SIP. This action is being taken under the
Clean Air Act (CAA).
DATES: This final rule is effective on September 19, 2022.
ADDRESSES: EPA has established a docket for this action under Docket ID
Number EPA-R03-OAR-2017-0615. All documents in the docket are listed on
the 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
www.regulations.gov, or please contact the person identified in the For
Further Information Contact section for additional availability
information.
FOR FURTHER INFORMATION CONTACT: Megan Goold, Planning & Implementation
Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection
Agency, Region III, Four Penn Center, 1600 John F. Kennedy Boulevard,
Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-
2027. Ms. Goold can also be reached via electronic mail at
[email protected].
SUPPLEMENTARY INFORMATION:
I. Background
On March 17, 2022 (87 FR 15166), EPA published a notice of proposed
rulemaking (NPRM) for the Commonwealth of Pennsylvania. In the NPRM,
EPA provided notice to the Commonwealth and the public and described
the basis for its determination that it had erroneously fully approved
the Indiana, PA SO2 Attainment Plan, and proposed to revise
its formal approval of the Plan to a partial disapproval and partial
approval. See CAA section 110(k)(6). The formal SIP revision was
originally submitted by Pennsylvania on October 11, 2017, and later
supplemented on February 5, 2020. EPA took final action approving this
attainment plan on October 19, 2020 (85 FR 66240).
On December 18, 2020, the Sierra Club, Clean Air Council, and
PennFuture filed a petition for judicial review with the U.S. Court of
Appeals for the Third Circuit, challenging that final approval.\1\ On
April 5, 2021, EPA filed a motion for voluntary remand without vacatur
of its approval of the Indiana, PA SO2 attainment plan. On
August 17, 2021, the U.S. Court of Appeals for the Third Circuit
granted EPA's request for remand without vacatur of the final approval
of Pennsylvania's SO2 attainment plan for the Indiana, PA
NAA, and required that EPA take final action in response to the remand
no later than one year from the date of the court's order (i.e., by
August 17, 2022). This action finalizes EPA's response to the court's
order.
---------------------------------------------------------------------------
\1\ Sierra Club, et. al v. EPA, Case No. 20-3568 (3rd Cir.).
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II. Summary of SIP Revision and EPA Analysis
In accordance with section 172(c) of the CAA, the Pennsylvania
attainment plan for the Indiana Area includes an emissions inventory
for SO2 for the plan's base year (2011) and an attainment
demonstration. The attainment demonstration includes the following: (1)
analyses that locate, identify, and quantify sources of emissions
contributing to violations of the 2010 SO2 NAAQS; (2) a
determination that the control strategy for the primary SO2
sources within the nonattainment areas constitutes RACM/RACT; (3) a
dispersion modeling analysis of an emissions control strategy for the
primary SO2 sources contributing to SO2
concentrations in the Area (Keystone, Conemaugh, Homer City, and
Seward) purporting to show attainment of the SO2 NAAQS by
the October 4, 2018, attainment date; (4) requirements for RFP toward
attaining the SO2 NAAQS in the Area; (5) contingency
measures; (6) the assertion that Pennsylvania's existing SIP-approved
new source review (NSR) program meets the applicable requirements for
SO2; and (7) the request that emission limitations and
compliance parameters for Keystone, Conemaugh, Homer City, and Seward
be incorporated into the SIP.
On February 5, 2020, in response to comments submitting during the
proposal's public comment period, PADEP submitted supplemental
information in support of the attainment plan. The February 5, 2020
submittal included: (1) a supplemental air dispersion modeling report;
(2) supplemental air dispersion modeling data; (3) a supplemental air
dispersion modeling protocol; (4) a meteorological monitoring plan; (5)
meteorological monitoring data; (6) meteorological monitoring quality
assurance, quality control, and audit reports; (7) Clean Air Markets
Division (CAMD) emissions data for 2010-2018; and (8) Continuous
Emissions Monitoring (CEM) data for 2010 through the third quarter of
2019. The supplemental air dispersion modeling used a more refined
model receptor grid than that in the original submittal, meteorological
data collected near the controlling modeled source (Seward), and more
recent (2016-18) background concentrations from the South Fayette
SO2 monitor (the monitor used to determine background
concentrations in the original modeling analysis). In order to allow
for public comment on this supplemental
[[Page 50779]]
information and modeling, on March 9, 2020 (85 FR 13602), EPA published
a notice of data availability (NODA) for the February 5, 2020,
submittal.
EPA now has determined that it was in error to fully approve the
Indiana, PA SO2 attainment plan, and is revising and
correcting its prior action in the same manner as the prior full
approval without further submission from the Commonwealth. See CAA
section 110(k)(6). EPA is retaining the approval of the emissions
inventory and nonattainment new source review (NNSR) program
requirements, and is finalizing disapproval of the attainment
demonstration, RACM/RACT requirements, RFP requirements, and
contingency measures.
Other specific requirements of section 172(c) and the rationale for
EPA's proposed and final action are explained in the NPRM, and its
associated technical support document (TSD), and will not be restated
here.
III. EPA's Response to Comments Received
EPA received two sets of comments on the notice of proposed
rulemaking for this action. A summary of the comments and EPA's
responses are provided below. To view the full set of comments, refer
to the docket for this action, Docket EPA-R03-OAR-2017-0615.
Comment 1: The commenter disagrees that the SIP did not include an
assessment showing that the longer-term average limits for Keystone and
Seward are of comparable stringency to the one-hour Critical Emissions
Value (CEV). The commenter believes that Appendix C of EPA's 2014
Guidance for 1-hour SO2 Nonattainment Area SIP Submissions
\2\ (``2014 Guidance'') is a statistical approach and is a surrogate
approach that was justified by Appendix B, such that Appendix C is a
theorem and Appendix B is the proof. The commenter states that the
Randomly Reassigned Emissions (RRE) modeling approach provides a very
robust demonstration of a comparably stringent relationship between the
modeling results of the CEV analysis and the RRE analysis. The
commenter believes the facts below support that the longer-term average
limits have been shown to be comparably stringent to the one-hour CEV,
and that the RRE modeling is thorough in testing the emissions
distributions that had the following attributes:
---------------------------------------------------------------------------
\2\ EPA Guidance for 1-hour SO2 Nonattainment Area
SIP Submissions, April 23, 2014, www.epa.gov/sites/default/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
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1. The emissions used in the RRE modeling followed Appendix C of
the 2014 Guidance because they reflected the distribution of emissions
expected once the attainment plan had been implemented.
2. High emission events were modeled in a way that is
representative of both the variability shown by the 2016 emissions data
and of the expected distribution of emissions occurring in compliance
with the allowable longer-term average emissions limits.
3. High emission events (i.e., hours with emissions above the CEV)
were randomly placed throughout the year in the modeling in order to
examine combinations of high emissions and varying meteorology.
4. Each of the 100 runs resulted in modeled design values below the
NAAQS, which the commenter asserts is a stringent requirement that is
equivalently stringent to the modeling results for the one-hour CEV
analysis, which has the same modeling outcome.
Therefore, the commenter asserts that Pennsylvania's RRE modeling
did incorporate the necessary steps to establish the comparably
stringent relationship between a modeled one-hour CEV and the longer-
term average limits.
The commenter also asserts that the fact that its RRE modeling
approach--which EPA used in Appendix B to test the statistical
adjustment approach in Appendix C--results in different longer-term
average limits than the Appendix C approach in this specific case, is
not contrary to the 2014 Guidance because they both demonstrate
attainment. They argue that the direct use of the submitted modeling
approach can be viewed as the gold standard, with a very high level of
confidence that the emissions distribution is protective of the NAAQS.
The commenter also claims that Appendix B uses an emissions
distribution that is expected once the plan is in place, which is the
same type of emissions data used in the Appendix C approach. The
commenter continues that EPA's guidance does not require the use of the
99th percentile of historic hourly data in the future emissions
profile.
The commenter is also concerned that EPA is requiring a clear link
between the modeled one-hour CEV and the longer-term average emission
limits even though the words ``clear'' and ``link'' do not appear in
the 2014 Guidance document. Although the commenter disagrees with the
requirement to demonstrate a clear link between the modeled 1-hr CEV
and the longer-term average limits, and with EPA's position that its
modeled future emissions scenarios must represent the worst case
emissions scenarios permissible under the limit, the commenter believes
that the RRE modeling has satisfied those requirements because, (1) the
CEV was used as one of the bins in the modeling, thus demonstrating a
clear link in the commenter's view, and (2) based on the commenter's
comparison of modeled emissions (future expected emissions), and actual
emissions from 2017-2021 for Keystone and Seward, the sources have
actually had a fewer number of hours above the CEV than was modeled,
and there have been no observed one-hour emissions from either source
equaling or exceeding the highest hourly emissions used in the peak
modeled emissions bin.
The commenter continues that discount factors were calculated from
the RRE modeling of 0.989 for Keystone and 0.686 for Seward, which are
consistent with the range of the discount values listed in Appendix D.
Response 1: In general, the commenter is misinterpreting the 2014
Guidance and conflating the use of Appendix B of the guidance as an
apparent alternate method of satisfying the SIP requirements. A SIP
requires that the plan provide for attainment of the NAAQS. Attainment
of the NAAQS is successfully demonstrated when the affected sources
operate within the limits in the plan such that emissions from any and
all variable operating scenarios are in compliance with those limits
and do not lead to NAAQS violations. Modeling the maximum one-hour
emission rate (i.e., the maximum allowable rate or `worst-case') that
yields a design concentration below the NAAQS is the means by which the
SIP provides for attainment. So, a one-hour limit is the mechanism for
providing for attainment in the SIP. In the alternative to the one-hour
limit, the 2014 Guidance provides flexibility for developing limits
with longer-term averages (up to 30-days). Appendix C describes the
method to develop longer-term limits that are comparably stringent to
the maximum one-hour limit. Appendix C uses the 99th percentile
distribution of emissions to ensure that the longer-term limits are
appropriately adjusted to be comparably stringent, and by extension,
provide for attainment. Appendix B is merely a diagnostic tool using a
statistical example as a back check to demonstrate that the 99th
percentile consideration used in Appendix C is the appropriate means to
show comparable stringency.
[[Page 50780]]
Appendix B is not a tool which can be decoupled from Appendix C to
develop limits sufficient to provide for attainment. Accordingly, the
state SIP cannot be said to provide for attainment because the longer-
term limits have not been shown to be comparably stringent to the one-
hour maximum allowable value. The worst case emissions scenario has not
been simulated (for example by a 99th percentile evaluation of the
emission distribution), and therefore the RRE analysis does not
demonstrate that the longer-term limit that the commenter claims is
proven by the RRE analysis will provide for attainment actually does
so, when it was performed by modeling future expected operating
scenarios that did not simulate worst case conditions. Using Appendix B
as a standalone tool to develop emission limits, as the state has done
here, is not appropriate without considering worst case emissions,
which is accomplished by linking to the CEV as is reflected in Appendix
C. The variable emissions modeling approach used by the state provides
no direct means of assessing whether any particular long-term limit is
of comparable stringency to any particular one-hour limit.
The 2014 Guidance did not remove the requirement for an attainment
demonstration to be based on maximum allowable emissions (as the
commenter implies), nor did it recommend basing attainment modeling on
an expected hourly distribution of emissions once the attainment plan
had been implemented (as the commenter implies). The 2014 Guidance
stated that ``for SO2 modeling, maximum allowable emissions
are the basis of the emissions input to the model in accordance with
Section 8 of Appendix W and past SO2 guidance (U.S. EPA,
1994).'' (2014 Guidance, pg. A-5). Furthermore, the Guidance used the
term critical emission value to refer to the hourly emission rate that
the model predicts would result in the 5-year average of the annual
99th percentile of daily maximum hourly SO2 concentrations
at the level of the one-hour NAAQS, given representative meteorological
data for the area. (2014 Guidance, pg. 23). The guidance provided a
methodology by which the maximum allowable modeled hourly emissions CEV
would be clearly linked to the comparably stringent longer-term average
limit. While the terms ``clear'' and ``link'' are not included in the
guidance document, the methods set forth in Appendix C describe a step-
by-step process by which an adjustment factor can be calculated, which
would then be directly applied to the CEV to create a comparably
stringent longer-term average limit. Consequently, if the CEV changed,
the comparably stringent longer-term limit would also change as a
result of the application of the adjustment factor.
Regardless of whether the guidance document uses the words `clear'
and `link,' the absence of a direct showing that the limits in
Pennsylvania's SIP are comparably stringent to the one-hour limits
modeled as necessary to provide for attainment means that the plan
presumptively does not provide adequate assurance of attainment.
Further, the commenter does not make a consistent argument that long-
term limits may be justified by modeling a significantly different
level of emissions (i.e., not maximum allowable emissions) than the
emissions that must be modeled to determine one-hour limits.
Additionally, the adjustment factor as specified in the 2014
Guidance is derived from a statistical analysis of a set of data that
reflect the emissions variability that the controlled source is
expected to exhibit. Specifically, the adjustment factor is calculated
by comparing the 99th percentile of hourly emissions data (from the
previously described data set) compared to the 99th percentile of the
longer-term averaging period values. This comparison at the higher end
of the distribution (99th percentile) of data values is purposeful
because ``the goal of the analyses is to identify a longer-term average
limit that requires a comparable degree of control, particularly at
times of greatest emissions as would be required by the 1-hr limit that
would otherwise be set, the EPA would expect the analyses to compare
the corresponding longer-term average and the 1-hr values among times
of greatest emissions'' (2014 Guidance, pg. 29). Without undertaking
this comparison, EPA does not believe it is able to determine that a
longer-term average limit is comparably stringent to the one-hour limit
that would otherwise be necessary to demonstrate attainment of the one-
hour NAAQS. The state's plan has not evaluated how the modeled
emissions compare to worst case emissions that are allowable under the
long-term limits, either in terms of whether the SIP modeled the
maximum allowable emissions or in terms of whether a worst case
distribution of emissions was modeled. Therefore, EPA does not have
evidence that the modeled emissions was a conservative distribution of
emissions in relation to the relevant benchmark of worst case allowable
emissions.
EPA does not agree that the RRE modeling provided this necessary
type of comparably stringent analysis. First, as the commenter points
out, although the CEV was used as one of the bins of hourly emission
values in the modeling, the state's longer-term limit was not based on
that CEV such that if the CEV changed the longer-term limit would in
turn change in the same direction. As noted in the proposal for this
rule, in the supplemental modeling analysis Pennsylvania submitted for
Seward, when Seward's CEV decreased by 579 pounds per hour (lb/hr)
(from 5,079 lb/hr to 4,500 lb/hr), the longer-term limit derived by
Pennsylvania from the RRE modeling remained unchanged. The air quality
found by modeling of variable emissions is a function of the full range
of modeled emissions, influenced by the frequency and magnitude of
emission values in all parts of the distribution, and so the use of the
CEV as one of the bin values provides almost no assurance that the full
RRE modeling analysis which includes other binned emissions is linked
in any meaningful way to the CEV.
Additionally, the RRE approach used the entire distribution of past
annual hourly emissions to set a longer-term average limit, rather than
the 99th percentile of annual hourly emissions, which does not satisfy
EPA's recommendation to use the time of greatest emissions, and thus
fails the Appendix C test for comparable stringency (2014 Guidance, pg.
29).
The commenter seems to be confused about what values in the
analysis need to be comparably stringent; the commenter claims that the
modeling results of the RRE modeling approach are comparably stringent
to the one-hour CEV modeling because both show design values below the
NAAQS. The values that need to be comparably stringent are the CEV and
the longer-term limit, not the modeled SO2 design values.
The modeled design values are dependent on the model inputs,
particularly the hourly emissions modeled. While EPA recommended that
the ``comparably stringent'' assessment be based on a set of emissions
data that can be expected to reflect the variability of emissions once
the subject source implements its attainment plan, this recommendation
was in conjunction with the recommendation to use the times of greatest
emissions (which the Guidance suggests is properly simulated by using
the 99th percentile distribution), and to begin the comparably
stringent analysis with the CEV. The commenter seems to have
misconstrued these recommendations and incorrectly concluded that
modeling an historic hourly distribution
[[Page 50781]]
of emissions for a source in an attainment modeling demonstration could
be used as a substitute to modeling maximum allowable emissions, or to
determining the CEV and then adjusting that value to calculate a
comparably stringent longer-term limit. Pennsylvania's RRE modeling did
not model maximum allowable emissions, nor did it demonstrate a
relationship between the CEV (maximum allowable hourly emission value)
and the longer-term average limit as recommended in EPA's 2014 Guidance
in order to enable a conclusion that the longer-term limits are
comparably stringent to the one-hour CEV.
Pennsylvania's RRE analysis modeled the entire distribution of
historic hourly emissions in 100 randomly assigned model runs; and in
the case for Seward, it set the 30-day limit at the weighted average of
hourly emissions modeled, and in the case for Keystone, it set the 24-
hour limit at the longer-term value that was modeled 30% of the year.
It is questionable whether either of these longer-term average limits
are actually being tested in the RRE model runs, or whether the model
runs only test the distribution of hourly emissions that were modeled.
EPA is not confident that these RRE derived longer-term limits will act
as a constraint on the distribution of future hourly emissions to the
same degree as the Appendix C approach using the 99th percentile value,
and therefore EPA does not have the same degree of confidence that the
NAAQS will not be violated. The future hourly emissions distribution
could skew towards having more frequent hourly values above or near the
CEV, in which case the RRE modeling performed for these sources might
not show design values complying with the NAAQS considering the
modeling results from the RRE modeling resulted in design values
extremely close to the 75 parts per billion (ppb) standard (as
discussed in more detail below). Additionally, Pennsylvania's use of a
limited number of emission bins with a high emissions ``floor'' adds a
further disconnect from the real distribution of worse case emissions.
Appendix B provided results of a variety of emissions scenarios for
a suitably adjusted longer-term average limit, which consistently
resulted in design values between 39 and 59 ppb. EPA notes on page B-3
of the 2014 Guidance, ``in each of these simulations a substantial
number of hours (on average, just under one percent) had emissions
higher than the CEV. Nevertheless, given the margin between these
values and the NAAQS level of 75 ppb, this analysis indicates that the
likelihood of a violation occurring with these emissions values is
extremely low.'' The RRE modeling provided by Pennsylvania in support
of Seward's 30-day limit and Keystone's 24-hour limit resulted in
design values just slightly below the 75 ppb NAAQS, which provides very
little margin by which hourly emissions could vary from those modeled
by Pennsylvania and not cause a violation. If Pennsylvania had properly
accounted for worst case emissions allowable under the limit, it is
quite possible that would have shown a violation.
Combining the impacts of using the 99th percentile of emissions
statistics, and the large margin between the resultant modeled
concentration in Appendix B and the level of the NAAQS, EPA is
confident that a longer-term average limit based on the Appendix C
methodology can be protective of the NAAQS. In contrast, the state has
provided an RRE modeled demonstration of expected future hourly
emissions, that when modeled, results in design values that come near
to violating the NAAQS while also reflecting compliance with the
longer-term average limits but at emissions scenarios not
representative of worst case emissions levels allowed under the longer-
term average limits. The State's submission does not provide confidence
that a comparably stringent relationship (as the commenter claims)
exists and therefore, does not provide a sufficient level of assurance
that the longer-term average limits provide for NAAQS attainment.
In support of its claim that the RRE modeling demonstrated
attainment using worst case emission scenarios, the commenter provided
an analysis which purportedly showed that more recent emissions (2017-
2021) had less hours above the CEV than the hourly emissions modeled
for Seward and Keystone. However, no evidence was provided that the
distribution of hourly emissions modeled by the RRE runs were
comparable to the worst-case hourly emissions scenario that could occur
in compliance with the longer-term emission limit. The commenter's
comparison of binned hourly emissions values modeled to those that
actually occurred throughout recent years, does not provide evidence of
worst case hourly emissions scenarios for a one-hour NAAQS. In
contrast, a different commenter provided modeling of Keystone's actual
emissions from 2019-2021, which purportedly showed that modeled NAAQS
violations occurred when the source was in compliance with the 24-hour
limit of 9600 lb/hr, and that the source's hourly emissions exceeded
the CEV during 35 hours in 2019, 69 hours in 2020, and 232 hours in
2021. This modeling analysis demonstrates that when a different
emissions scenario is modeled from Pennsylvania's RRE modeling, a NAAQS
violation occurs, highlighting the importance of modeling worst case
emissions to ensure attainment.
The RRE modeling approach used by Pennsylvania did not reflect the
maximum possible emissions that could occur while maintaining
compliance with the longer-term average emission limit, nor did the
approach provide a comparably stringent analysis. Consequently, it was
erroneous for EPA to fully approve the Indiana, PA SO2
Attainment Plan in 2020, and it is necessary for EPA to correct its
error by revising its action to partially approve and partially
disapprove the Plan.
Comment 2: The commenter notes that the monitors do not show
evidence of nonattainment, and noted that, even though the Strongstown
monitor is not located in the area of the modeled maximum
SO2 concentration, previous modeling demonstrated that the
Strongstown monitor would be ``significantly impacted'' if elevated
impacts occurred elsewhere in the Indiana, PA NAA. The commenter
provided data from the Strongstown monitor showing that its monitored
values are decreasing and approaching values from the background
monitor in South Fayette.
Response 2: EPA agrees that the monitors in Strongstown and South
Fayette are reading below the standard. However, as noted by the
commenter, the monitors are not located in the area of modeled maximum
concentrations and therefore are not, by themselves, indicative of
whether the area is meeting the SO2 NAAQS. Although the
comment makes reference to the ``modeling effort,'' it is not clear
what modeling the commenter is referring to and the commenter has not
provided any other data to support the claim that the Strongstown
monitor would be ``significantly impacted'' if elevated impacts
occurred elsewhere in Indiana, PA.
SO2 concentrations result from direct emissions from
combustion sources so that concentrations are highest relatively close
to sources and are much lower at greater distances due to dispersion,
i.e., a strong concentration gradient. Given the source-oriented nature
of this pollutant (see 75 FR at 35570, June 22, 2010), dispersion
models are the most appropriate air quality modeling tools to predict
the near field concentrations and gradients
[[Page 50782]]
of this pollutant. EPA has received dispersion modeling from a
different commenter that purportedly shows modeled violations within
the Indiana, PA NAA near the Indiana and Armstrong County border, using
actual 2019-2021 emissions for Keystone, while the source was
purportedly complying with the 24-hour limit of 9,600 lb/hr.
Consequently, EPA does not regard the commenter's observations about
the Strongstown monitor as providing persuasive evidence that the Area
is not violating the NAAQS or that the Plan provides for attainment of
the NAAQS.
Comment 3: The commenter claims that EPA is acting inconsistently
because EPA approved the use of an alternative modeling method in
Miami, AZ, which used Appendix C to calculate an adjustment factor, and
included a supporting Appendix B modeling demonstration, which the
commenter claims ``definitively'' confirmed the adequacy of the
Appendix C calculated adjustment factor. The commenter argues that
Appendix B was used as an essential component of the SIP because
Appendix C was used in an application not addressed in EPA's 2014
Guidance. Further, the commenter argues that the regulatory requirement
is attainment of the NAAQS. The commenter alleges that this disapproval
is arbitrary and capricious because it proposes to interpret the
guidance differently in two nonattainment areas and apply it
inconsistently without any explanation for the inconsistency.
Response 3: EPA disagrees that it has applied the 2014 Guidance
inconsistently between the Indiana, PA attainment plan and the Miami,
AZ attainment plan. As the commenter noted, a significant difference
between the two plans is that the Arizona plan used the Appendix C
methodology to calculate a comparably stringent longer-term average
limit, and then provided additional modeling to analyze whether the
longer-term emission limit derived using Appendix C was reasonably
likely to be protective of the NAAQS. In contrast, Pennsylvania used
RRE modeling to arrive at the longer-term average limit without
demonstrating comparable stringency to the one-hour CEV. The Arizona
longer-term limit was calculated by obtaining a ratio of the 99th
percentile of hourly emissions compared to the 99th percentile of
longer-term average values as recommended by EPA. This ratio or
adjustment factor was then applied to the CEV, thus taking into account
the times of greatest emissions and linking the longer-term limit to
the maximum modeled emission value (CEV), accordingly. Although the
Arizona plan included an RRE-type (i.e., Appendix B) assessment of
projected air quality, EPA did not rely on that assessment and made no
reference to it in its final rule, insofar as the SIP was approvable
without regard to the merits of the assessment.
In contrast, the longer-term limits for Keystone and Seward in the
Indiana, PA attainment plan were developed using only RRE modeling,
which modeled the entire distribution of historic hourly emissions and
based the limit on the 24-hour values that were modeled 30% of the time
(Keystone) and the weighted annual average (Seward), neither of which
considered the 99th percentile statistics of the historic hourly data
set (times of greatest emissions), and neither of which were linked to
the maximum modeled hourly emission rate (CEV). While sources can use
approaches other than Appendix C to derive a longer-term average limit,
the evidence that the other approach will result in attainment needs to
be as compelling. EPA believes that any approach used should begin with
the CEV, and account for times of greatest emissions in setting a
longer-term limit. EPA also has noted that supplemental limits may be
necessary to further constrain the frequency and magnitude of these
worst case emission episodes.
Due to these clear differences in approaches, EPA is not acting
inconsistently in our actions on the Indiana, PA and Miami, AZ
attainment plans as the commenter claims; rather, EPA is applying the
2014 Guidance consistently across rather dissimilar situations.
Comment 4: The commenter claims that EPA's action is arbitrary and
capricious because the disapproval is not based on a rational
connection between the facts found and the choice made. The commenter
asserts that the facts in the record show that Appendix B is the proof
of the statistical analysis in Appendix C, and that using the Appendix
B approach is a more robust, thorough way to show that a longer-term
emission limit can be protective of the NAAQS. The commenter claims
that the use of the Appendix B approach is consistent with EPA's
requirements for an approvable SIP: ``. . . as the EPA explained in our
2014 SO2 Guidance and in numerous proposed and final SIP
actions implementing the SO2 NAAQS, a key element of an
approvable SIP is the required modeling demonstration showing that the
remedial control measures and strategy are adequate to bring a
previously or currently violating area into attainment.'' 84 FR 8815,
March 12, 2019. EPA is now seemingly self-contradictory and believes
that Appendix B does not provide a longer-term emission limit that is
equivalently stringent to the one-hour limit. Nothing in the record
supports making this determination, the commenter claims.
Response 4: EPA disagrees with the commenter and believes the
commenter has misunderstood the purpose of Appendix B of the 2014
Guidance. First, the EPA language quoted by the commenter is referring
to the modeling performed to determine the CEV, which is a one-hour
limit for SO2 emissions, rather than a longer-term limit.
Also, as noted in the 2014 Guidance, ``Appendix B documents analyses
that the EPA has conducted to evaluate the extent to which longer-term
limits that have been adjusted to have comparable stringency to one-
hour limits as the critical emissions value provide for attainment.''
(pg. 25). Also, as noted in the Guidance, ``at issue is the likelihood
that a source complying with a 30-day average limit reflecting the
adjustment generally recommended in this guidance [emphasis added]
would have sufficiently high emissions on a sufficient fraction of the
potential exceedance days to cause an SO2 NAAQS violation.''
(pg. B-2). In each of the modeling simulations run by EPA in support of
the Appendix C methodology, the estimated design values obtained were
between 39 and 58 ppb, and thus EPA stated, ``Given the margin between
these values and the NAAQS level of 75 ppb, this analysis indicates
that the likelihood of a violation occurring with these emissions
values is extremely low.'' (pg. B-3). Thus, the modeling exercise was
conducted as a test on emission limits that were considered comparably
stringent with the CEV (i.e., comparably stringent longer-term emission
limits, and not simply ``longer-term'' emission limits); it was not
used to develop the comparably stringent longer-term limits because, as
noted, the results of the Appendix B analyses yielded a range of
estimated design values and EPA did not select a specific modeling
scenario result to rely upon as an attainment demonstration. Rather,
EPA used the analysis as support that the comparably stringent longer-
term limit derived using the Appendix C methodology, notwithstanding
infrequent hourly emissions spikes above the CEV, could nevertheless
protect the NAAQS.
The commenter's claim that Appendix B is a ``proof'' of the
statistical analysis in Appendix C is not substantiated. A mathematical
proof of a theorem should show that the theorem holds true at all times
so long as any
[[Page 50783]]
constraints set forth by the theorem are followed (e.g., theorem only
applies to prime numbers). In Appendix B, EPA summarizes modeling
exercises that were conducted using the emission patterns that could be
expected even when a source is just barely complying with a long-term
average emission limit. (2014 Guidance, at B-4). Based on this, EPA
concluded that these analyses indicated ``that suitably adjusted
longer-term average limits can generally be expected to provide
adequate confidence that the attainment plan will provide for
attainment.'' (pg. B-2). Words such as ``generally'' and ``adequate
confidence'' are not words used to describe a mathematical proof.
The modeling analyses were one piece of evidence that provided more
confidence to EPA that a comparably stringent longer-term limit (set
using the 99th percentile of emissions statistics) can be protective of
a one-hour NAAQS, but the Appendix B modeling analyses did not
``prove'' that a longer-term limit set via other methods that went
through 100 model runs with a specified hourly emissions distribution
and that modeled attainment would provide the same level of confidence
that the limit is protective of the one-hour NAAQS. More specifically,
Pennsylvania modeled hourly values that, when averaged over a 24-hour
day, equaled less than the 24-hour limit for 70% of the year for
Keystone. That is, while the 24-hour limit for Keystone was set at
9,600 lb/hr, the hourly emissions that were modeled averaged between
5,000 and 8,964 lb/hr on a 24-hour basis for 70% of the year; and the
hourly emissions that were modeled averaged 9,600 lb/hr on a 24-hour
basis for 30% of the year. Pennsylvania did not scale the data set such
that the modeled hourly values resulted in 24-hour averages that just
met the 24-hour limit of 9,600 lb/hr. Therefore, it's questionable
whether the RRE modeling actually tested the 24-hour limit for
Keystone. If the 24-hour averaged emissions varied from those that were
modeled, such that 50% or 100% of the 24-hour averages equaled 9,600
lb/hr (the limit) rather than only 30%, it is uncertain that the
modeled concentrations would still result in attainment. On the other
hand, EPA's methods for determining a comparably stringent limit do
provide confidence that changes in the hourly emissions distribution
while in compliance with the longer-term limit will still provide for
attainment. Tellingly, at no point does the guidance recommend use of
the methods described in Appendix B as a means of determining suitable
limits or of determining whether limits determined by other means
(whether of comparable stringency to a one-hour limit at the CEV or
not) will suitably provide for attainment. Thus, characterizing
Appendix B as `proof' of the Appendix C theorem is off base.
Comment 5: A different commenter claims that longer-term limits are
fundamentally incapable of protecting a one-hour NAAQS. The commenter
provided an updated analysis of Keystone's actual hourly emissions for
the years 2018 through 2021 which showed that the source exceeded the
CEV over 500 hours. The commenter noted that 2021 was worse than 2020.
The analysis also showed that Seward exceeded the CEV 71 times in that
same period (4 years). The commenter believes that the NAAQS will not
be attained if just four hours on four days have ambient concentrations
above 75 ppb, and thus concludes that longer-term emissions averaging
cannot protect the NAAQS. The commenter therefore asserts that the
current emission limits in the SIP for Keystone and Seward are
inadequate to protect air quality.
In addition, the commenter calculated a conversion factor for
Keystone using Appendix C and the more recent 2018-2021 hourly
emissions data and noted the analysis yields a limit of 8,292.5 lb/hr
(24-hour daily average), which is below the current limit of 9,600 lb/
hr as a 24-hour daily average.
Response 5: EPA disagrees with the commenter's assertion that a
longer-term limit, so long as it is properly set, cannot protect a one-
hour NAAQS. But that abstract issue is not being decided in this
action. In this case, EPA agrees with the commenter that the specific
longer-term limits for Keystone and Seward were not set at a level that
ensures the protection of the one-hour SO2 NAAQS, since they
were not shown to be comparably stringent to a modeled attaining one-
hour CEV. EPA agrees with the commenter that the longer-term limits for
Keystone and Seward do not ensure protection of the NAAQS, and with
this action will finalize disapproval of the attainment demonstration.
Comment 6: The commenter provided recent air quality modeling
allegedly demonstrating that SO2 emissions from Keystone,
Conemaugh, and Seward continue to cause nonattainment in Pennsylvania,
both inside and outside the Indiana NAA. The air quality modeling
submitted with the comment, which used actual emissions from Keystone
from 2019 through 2021, purportedly demonstrates that Keystone is
causing violations of the NAAQS (209.9 micrograms per cubic meter
([micro]g/m\3\)). The commenter also provided annual SO2
emissions for Keystone, which show lower annual emissions in 2020
(13,011 tons per year), but other years range from 17,000-24,000 tons
per year. Using actual emissions for various three-year time periods
from 2015-2017 through 2019-2021, the commenter provided modeling
demonstrating that Seward and Conemaugh cause violations of the NAAQS
(244.6 [micro]g/m\3\-275.4 [micro]g/m\3\) \3\ outside the nonattainment
area.
---------------------------------------------------------------------------
\3\ In the Round 3 intended designations (82 FR 41903) published
September 5, 2017, EPA endorsed a value of 196.4 [micro]g/m\3\
(based on calculations using all available significant figures) as
equivalent to 75 ppb.
---------------------------------------------------------------------------
Response 6: EPA believes that this final rule may result in
Pennsylvania adopting tighter SO2 emission limits for both
Keystone and Seward which will reduce their hourly emissions and better
provide for reductions in SO2 concentrations towards
achieving attainment of the NAAQS, subject to EPA's evaluation of any
such future limits.
Regarding the commenter's modeling, which seems to show modeled
SO2 NAAQS violations in Westmoreland and Cambria counties in
Pennsylvania outside the boundaries of the Indiana NAA, EPA notes that
it is not basing its partial disapproval of the Indiana attainment plan
on these modeled NAAQS violations outside of the Indiana NAA. As stated
in the proposal for this action, EPA is planning a separate regulatory
action under the Clean Air Act to address those modeled NAAQS
violations.
Comment 7: The commenter states that Conemaugh and Seward's
SO2 pollution implicates serious environmental justice (EJ)
concerns. The commenter provided an EJ Screen analysis which indicates
that southeast of Seward the population is characterized by low incomes
and generally elderly population. The commenter also overlaid the
modeled violations of the NAAQS with the EJ screen map showing that the
modeled violations are impacting the identified vulnerable population.
The commenter asserts that this adds urgency to the need for attainment
to be achieved and SO2 emissions from Conemaugh and Seward
to be properly limited.
Response 7: EPA's analysis in the notice of proposed rulemaking
showed similar results to the commenter's EJ screen analysis and
indicated communities with environmental justice concerns both inside
and outside the Indiana nonattainment area. EPA therefore encourages
Pennsylvania to be as expeditious as practicable in
[[Page 50784]]
developing its new attainment plan limits in order to address the
emissions impact on the vulnerable populations both inside the current
nonattainment area, and in adjacent areas.
IV. Final Action
EPA is partially approving and partially disapproving the Indiana,
PA attainment plan as a correction of its erroneous prior full approval
action and as a revision to the Pennsylvania SIP. See CAA section
110(k)(6). Specifically, EPA is disapproving the attainment
demonstration, RACT/RACM determination, RFP requirements, and
contingency measures. EPA is retaining the approval of the emissions
inventory and the NNSR program.
This action initiates a sanctions clock under CAA section 179,
providing for emission offset sanctions for new sources if EPA has not
fully approved a revised SIP attainment plan within 18 months after
final partial disapproval, and providing for highway funding sanctions
if EPA has not fully approved a revised plan within 6 months
thereafter. The sanctions clock can be stopped only if the conditions
of EPA's regulations at 40 CFR 52.31 are met. This action also
initiates an obligation for EPA to promulgate a Federal implementation
plan within 24 months unless Pennsylvania has submitted, and EPA has
fully approved, a plan addressing these attainment planning
requirements.
V. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at www.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA, because this SIP partial approval and partial disapproval does
not in-and-of itself create any new information collection burdens, but
simply partially approves and partially disapproves certain State
requirements for inclusion in the SIP.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. This SIP
partial approval and partial disapproval does not in-and-of itself
create any new requirements but simply partially approves and partially
disapproves certain pre-existing State requirements for inclusion in
the SIP.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action does not impose additional requirements
beyond those imposed by state law. Accordingly, no additional costs to
state, local, or tribal governments, or to the private sector, will
result from this action.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.
F. Executive Order 13175: Coordination With Indian Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175, because the SIP EPA is disapproving would not
apply on any Indian reservation land or in any other area where the EPA
or an Indian tribe has demonstrated that a tribe has jurisdiction, and
will not impose substantial direct costs on tribal governments or
preempt tribal law. Thus, Executive Order 13175 does not apply to this
action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive order. This action is not subject to
Executive Order 13045 because this SIP partial approval and partial
disapproval does not in-and-of itself create any new regulations, but
simply partially approves and partially disapproves certain pre-
existing State requirements for inclusion in the SIP.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.
I. National Technology Transfer and Advancement Act (NTTAA)
Section 12(d) of the NTTAA directs the EPA to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. The EPA
believes that this action is not subject to the requirements of section
12(d) of the NTTAA because application of those requirements would be
inconsistent with the CAA.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Population
The EPA lacks the discretionary authority to address environmental
justice in this rule.
K. Congressional Review Act (CRA)
This action is subject to the CRA, and the EPA will submit a rule
report to each House of the Congress and to the Comptroller General of
the United States. This action is not a ``major rule'' as defined by 5
U.S.C. 804(2).
L. 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 October 17, 2022. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this rule 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 pertaining to the partial approval and partial disapproval
of the Indiana, PA SO2 attainment plan, 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, Intergovernmental relations,
[[Page 50785]]
Reporting and recordkeeping requirements, Sulfur oxides.
Adam Ortiz,
Regional Administrator, Region III.
For the reasons stated in the preamble, the EPA amends 40 CFR part
52 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 (e)(1) is amended by adding
an entry ``Attainment Plan for the Indiana, Pennsylvania Nonattainment
Area for the 2010 Sulfur Dioxide Primary National Ambient Air Quality
Standard'' at the end of the table to read as follows:
Sec. 52.2020 Identification of plan.
* * * * *
(e) * * *
(1) * * *
----------------------------------------------------------------------------------------------------------------
Name of non- regulatory SIP Applicable State submittal
revision geographic area date EPA approval date Additional explanation
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Attainment Plan for the Indiana County 10/11/17, 8/18/22, [Insert Partial Disapproval
Indiana, Pennsylvania and portions of Supplemental Federal Register (attainment
Nonattainment Area for the Armstrong County information Citation]. demonstration,
2010 Sulfur Dioxide Primary (Plumcreek submitted 02/05/ 10/19/20, 85 FR Reasonably Available
National Ambient Air Quality Township, South 20, updated 66255. Control Technology
Standard. Bend Township, redacted permits (RACT)/Reasonably
and Elderton submitted on 05/ Available Control
Borough). 13/20. Measures (RACM)
determination,
Reasonable Further
Progress (RFP)
requirements,
contingency measures)
and Partial Approval
(emissions inventory
and nonattainment new
source review (NNSR)
program) 52.2033(f).
----------------------------------------------------------------------------------------------------------------
* * * * *
0
4. Amend Sec. 52.2033 by revising paragraph (f) to read as follows:
Sec. 52.2033 Control strategy: Sulfur oxides.
* * * * *
(f) EPA partially approves and partially disapproves the attainment
demonstration State Implementation Plan for the Indiana, PA Sulfur
Dioxide Nonattainment Area submitted by the Pennsylvania Department of
Environmental Protection on October 11, 2017 and updated on February 5,
2020, and corrected permits submitted on May 13, 2020. EPA approves the
base year inventory and the Nonattainment New Source Review (NNSR)
requirements, and disapproves the attainment demonstration, Reasonably
Available Control Technology (RACT)/Reasonably Available Control
Measures (RACM) determination, Reasonable Further Progress (RFP)
requirements and contingency measures.
[FR Doc. 2022-17449 Filed 8-17-22; 8:45 am]
BILLING CODE 6560-50-P