[Federal Register Volume 83, Number 194 (Friday, October 5, 2018)]
[Proposed Rules]
[Pages 50314-50326]
[FR Doc No: 2018-21667]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2017-0681; FRL-9984-98-Region 3]

Approval and Promulgation of Air Quality Implementation Plans;
Pennsylvania; Attainment Plan for the Beaver, Pennsylvania
Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient
Air Quality Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a state implementation plan (SIP) revision, submitted by the
Commonwealth of Pennsylvania through the Pennsylvania Department of
Environmental Protection (PADEP), to EPA on September 29, 2017, for the
purpose of providing for attainment of the 2010 sulfur dioxide
(SO2) primary national ambient air quality standard (NAAQS)
in the Beaver County, Pennsylvania SO2 nonattainment area
(hereafter referred to as the ``Beaver Area'' or ``Area''). The Beaver
Area is comprised of a portion of Beaver County (Industry Borough,
Shippingport Borough, Midland Borough, Brighton Township, Potter
Township and Vanport Township) in Pennsylvania. The SIP submission is
an attainment plan which includes the base year emissions inventory, an
analysis of the reasonably available control technology (RACT) and
reasonably available control measure (RACM) requirements, a reasonable
further progress (RFP) plan, a modeling demonstration of SO2
attainment, contingency measures for the Beaver Area, and
Pennsylvania's new source review (NSR) permitting program. As part of
approving the attainment plan, EPA is also proposing to approve into
the Pennsylvania SIP new SO2 emission limits and associated
compliance parameters for the FirstEnergy Generation, LLC (FirstEnergy)
Bruce Mansfield Power Station (Bruce Mansfield Facility) and a consent
order with Jewel Acquisition Midland steel plant (Jewel Facility). This
action is being taken under the Clean Air Act (CAA).

DATES: Written comments must be received on or before November 5, 2018.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-
OAR-2017-0681 at http://www.regulations.gov, or via email to
[email protected]. For comments submitted at Regulations.gov,
follow the online instructions for submitting comments. Once submitted,
comments cannot be edited or removed from Regulations.gov. For either
manner of submission, EPA may publish any comment received to its
public docket. Do not submit electronically any information you
consider to be confidential business information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e. on the web, cloud, or other file sharing
system). For additional submission methods, please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section. For the full
EPA public comment policy, information about CBI or multimedia
submissions, and general guidance on making effective comments, please
visit http://www2.epa.gov/dockets/commenting-epa-dockts.

FOR FURTHER INFORMATION CONTACT: Megan Goold<PHONE_NUMBER>, or by
email at [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background for EPA's Proposed Action
II. Requirements for SO2 Nonattainment Area Plan
III. Attainment Demonstration and Longer Averaging Times

IV. Pennsylvania's Attainment Plan Submittal for the Beaver Area
V. EPA's Analysis of Pennsylvania's Attainment Plan for the Beaver
Area
    A. Pollutants Addressed
    B. Emissions Inventory Requirements
    C. Air Quality Modeling
    D. RACM/RACT
    E. RFP Plan
    F. Contingency Measures
    G. New Source Review
VI. EPA's Proposed Action
VII. Incorporation by Reference
VIII. Statutory and Executive Order Reviews

I. Background for EPA's Proposed Action

    On June 2, 2010, the EPA Administrator signed a final rule
establishing a new SO2 NAAQS as a 1-hour standard of 75
parts per billion (ppb), based on a 3-year average of the annual 99th
percentile of 1-hour daily maximum concentrations. See 75 FR 35520
(June 22, 2010), codified at 40 CFR 50.17(a)-(b). This action also
revoked the existing 1971 primary annual and 24-hour standards, subject
to certain conditions.\1\ EPA established the NAAQS based on
significant evidence and numerous health studies demonstrating that
serious health effects are associated with short-term exposures to
SO2 emissions ranging from 5 minutes to 24 hours with an
array of adverse respiratory effects including narrowing of the airways
which can cause difficulty breathing (bronchoconstriction) and
increased asthma symptoms. For more information regarding the health
impacts of SO2, please refer to the June 22, 2010, final
rulemaking. See 75 FR 35520. Following promulgation of a new or revised
NAAQS, EPA is required by the CAA to designate areas throughout the
United States as attaining or not attaining the NAAQS; this designation
process is described in section 107(d)(1) of the CAA. On August 5,
2013, EPA promulgated initial air quality designations for 29 areas for
the 2010 SO2 NAAQS (78 FR 47191), which became effective on
October 4, 2013, based on violating air quality monitoring data for
calendar years 2009-2011, where there was sufficient data to support a
nonattainment designation.\2\
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    \1\ EPA's June 22, 2010 final action revoked the two 1971
primary 24-hour standard of 140 ppb and the annual standard of 30
ppb because they were determined not to add additional public health
protection given a 1-hour standard at 75 ppb. See 75 FR 35520.
However, the secondary 3-hour SO2 standard was retained.
Currently, the 24-hour and annual standards are only revoked for
certain of those areas the EPA has already designated for the 2010
1-hour SO2 NAAQS. See 40 CFR 50.4(e).
    \2\ EPA is continuing its designation efforts for the 2010
SO2 NAAQS. Pursuant to a court-order entered on March 2,
2015, by the U.S. District Court for the Northern District of
California, EPA must complete the remaining designations for the
rest of the country on a schedule that contains three specific
deadlines. Sierra Club, et al. v. Environmental Protection Agency,
13-cv-03953-SI (2015).
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    Effective on October 4, 2013, the Beaver Area was designated as
nonattainment for the 2010 SO2 NAAQS for an area that
encompasses several past and current sources of SO2
emissions and the nearby SO2 monitor (Air Quality Site ID:
42-007-0005). The October 4, 2013 final designation triggered a
requirement for Pennsylvania to submit a SIP revision with an
attainment plan for how the Area would attain the 2010 SO2
NAAQS as expeditiously as practicable, but no later than October 4,
2018, in accordance with CAA section 192(a).
    For a number of areas, including the Beaver Area, EPA published a
notice on March 18, 2016, effective April 18, 2016, that Pennsylvania
and other pertinent states had failed to submit the required
SO2 attainment plan by this submittal deadline. See 81 FR
14736. This finding initiated a deadline under CAA section 179(a) for
the potential imposition of new source review and highway funding
sanctions. However, pursuant to Pennsylvania's submittal of September
29, 2017, and EPA's subsequent letter dated October 5, 2017, to
Pennsylvania finding the submittal complete and noting the stopping of
these sanctions' deadline, these sanctions under section 179(a) will
not be imposed as a consequence of Pennsylvania's missing the SIP
submission deadline. Additionally, under CAA section 110(c), the March
18, 2016 finding triggers a requirement that EPA promulgate a federal
implementation plan (FIP) within two years of the finding unless, by
that time the state has made the necessary complete submittal and EPA
has approved the submittal as meeting applicable requirements. EPA's
obligation to promulgate and implement a FIP will not apply if EPA
makes final the approval action proposed here.

II. Requirements for SO2 Nonattainment Area Plans

    Attainment plans must meet the applicable requirements of the CAA,
and specifically CAA sections 110, 172, 191, and 192. The required
components of an attainment plan submittal are listed in section 172(c)
of Title 1, part D of the CAA. The EPA's regulations governing
nonattainment SIPs are set forth at 40 CFR part 51, with specific
procedural requirements and control strategy requirements residing at
subparts F and G, respectively. Soon after Congress enacted the 1990
Amendments to the CAA, EPA issued comprehensive guidance on SIPs, in a
document entitled the ``General Preamble for the Implementation of
Title I of the Clean Air Act Amendments of 1990,'' published at 57 FR
13498 (April 16, 1992) (General Preamble). Among other things, the
General Preamble addressed SO2 SIPs and fundamental
principles for SIP control strategies. Id. at 13545-49, 13567-68. On
April 23, 2014, EPA issued recommended guidance (hereafter 2014
SO2 Nonattainment Guidance) for how state submissions could
address the statutory requirements in SO2 attainment
plans.\3\ In this guidance, EPA described the statutory requirements
for an attainment plan, which include: An accurate base year emissions
inventory of current emissions for all sources of SO2 within
the nonattainment area (172(c)(3)); an attainment demonstration that
includes a modeling analysis showing that the enforceable emissions
limitations and other control measures taken by the state will provide
for expeditious attainment of the NAAQS (172(c)); demonstration of RFP
(172(c)(2)); implementation of RACM, including RACT (172(c)(1)); NSR
(172(c)(5)); and adequate contingency measures for the affected area
(172(c)(9)). A synopsis of these requirements is also provided in the
notice of proposed rulemaking on the Illinois SO2
nonattainment plans, published on October 5, 2017 at 82 FR 46434.
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    \3\ See ``Guidance for 1-Hour SO2 Nonattainment Area
SIP Submissions'' (April 23, 2014), available at https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
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    In order for the EPA to fully approve a SIP as meeting the
requirements of CAA sections 110, 172 and 191-192 and EPA's regulations
at 40 CFR part 51, the SIP for the affected area needs to demonstrate
to EPA's satisfaction that each of the aforementioned requirements have
been met. Under CAA sections 110(l) and 193, the EPA may not approve a
SIP that would interfere with any applicable requirement concerning
NAAQS attainment and RFP, or any other applicable requirement, and no
requirement in effect (or required to be adopted by an order,
settlement, agreement, or plan in effect before November 15, 1990) in
any area which is a nonattainment area for any air pollutant, may be
modified in any manner unless it ensures equivalent or

greater emission reductions of such air pollutant.

III. Attainment Demonstration and Longer Term Averaging

    CAA section 172(c)(1) directs states with areas designated as
nonattainment to demonstrate that the submitted plan provides for
attainment of the NAAQS. 40 CFR part 51, subpart G further delineates
the control strategy requirements that SIPs must meet, and EPA has long
required that all SIPs and control strategies reflect four fundamental
principles of quantification, enforceability, replicability, and
accountability. General Preamble, at 13567-68. SO2
attainment plans must consist of two components: (1) Emission limits
and other control measures that assure implementation of permanent,
enforceable and necessary emission controls, and (2) a modeling
analysis which meets the requirements of 40 CFR part 51, Appendix W
which demonstrates that these emission limits and control measures
provide for timely attainment of the primary SO2 NAAQS as
expeditiously as practicable, but by no later than the attainment date
for the affected area. In all cases, the emission limits and control
measures must be accompanied by appropriate methods and conditions to
determine compliance with the respective emission limits and control
measures and must be quantifiable (i.e., a specific amount of emission
reduction can be ascribed to the measures), fully enforceable
(specifying clear, unambiguous and measurable requirements for which
compliance can be practicably determined), replicable (the procedures
for determining compliance are sufficiently specific and non-subjective
so that two independent entities applying the procedures would obtain
the same result), and accountable (source specific limits must be
permanent and must reflect the assumptions used in the SIP
demonstrations).
    EPA's 2014 SO2 Nonattainment Guidance recommends that
the emission limits established for the attainment demonstration be
expressed as short-term average limits (e.g., addressing emissions
averaged over one or three hours), but also describes the option to
utilize emission limits with longer averaging times of up to 30 days so
long as the state meets various suggested criteria. See 2014
SO2 Nonattainment Guidance, pp. 22 to 39. The guidance
recommends that--should states and sources utilize longer averaging
times--the longer term average limit should be set at an adjusted level
that reflects a stringency comparable to the 1-hour average limit at
the critical emission value shown to provide for attainment that the
plan otherwise would have set.
    The 2014 SO2 Nonattainment Guidance provides an
extensive discussion of EPA's rationale for concluding that
appropriately set comparably stringent limitations based on averaging
times as long as 30 days can be found to provide for attainment of the
2010 SO2 NAAQS. In evaluating this option, EPA considered
the nature of the standard, conducted detailed analyses of the impact
of use of 30-day average limits on the prospects for attaining the
standard, and carefully reviewed how best to achieve an appropriate
balance among the various factors that warrant consideration in judging
whether a state's plan provides for attainment. Id. at pp. 22-39,
Appendices B, C, and D.
    As specified in 40 CFR 50.17(b), the 1-hour primary SO2
NAAQS is met at an ambient air quality monitoring site when the 3-year
average of the annual 99th percentile of daily maximum 1-hour
concentrations is less than or equal to 75 ppb. In a year with 365 days
of valid monitoring data, the 99th percentile would be the fourth
highest daily maximum 1-hour value. The 2010 SO2 NAAQS,
including this form of determining compliance with the standard, was
upheld by the U.S. Court of Appeals for the District of Columbia
Circuit in Nat'l Envt'l Dev. Ass'n's Clean Air Project v. EPA, 686 F.3d
803 (D.C. Cir. 2012). Because the standard has this form, a single
exceedance does not create a violation of the standard. Instead, at
issue is whether a source operating in compliance with a properly set
longer term average could cause exceedances, and if so the resulting
frequency and magnitude of such exceedances, and in particular, whether
EPA can have reasonable confidence that a properly set longer term
average limit will provide that the average fourth highest daily
maximum value will be at or below 75 ppb. A synopsis of how EPA
evaluates whether such plans ``provide for attainment,'' based on
modeling of projected allowable emissions and in light of the NAAQS'
form for determining attainment at monitoring sites follows.
    For plans for SO2 based on 1-hour emission limits, the
standard approach is to conduct modeling using fixed emission rates.
The maximum emission rate that would be modeled to result in attainment
(i.e., an ``average year'' \4\ shows three, not four days with maximum
hourly levels exceeding 75 ppb) is labeled the ``critical emission
value.'' The modeling process for identifying this critical emissions
value inherently considers the numerous variables that affect ambient
concentrations of SO2, such as meteorological data,
background concentrations, and topography. In the standard approach,
the state would then provide for attainment by setting a continuously
applicable 1-hour emission limit at this critical emission value.
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    \4\ An ``average year'' is used to mean a year with average air
quality. While 40 CFR 50 Appendix T provides for averaging three
years of 99th percentile daily maximum values (e.g., the fourth
highest maximum daily concentration in a year with 365 days with
valid data), this discussion and an example below uses a single
``average year'' in order to simplify the illustration of relevant
principles.
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    EPA recognizes that some sources have highly variable emissions,
for example due to variations in fuel sulfur content and operating
rate, that can make it extremely difficult, even with a well-designed
control strategy, to ensure in practice that emissions for any given
hour do not exceed the critical emission value. EPA also acknowledges
the concern that longer term emission limits can allow short periods
with emissions above the ``critical emissions value,'' which, if
coincident with meteorological conditions conducive to high
SO2 concentrations, could in turn create the possibility of
a NAAQS exceedance occurring on a day when an exceedance would not have
occurred if emissions were continuously controlled at the level
corresponding to the critical emission value. However, for several
reasons, EPA believes that the approach recommended in its guidance
document suitably addresses this concern. First, from a practical
perspective, EPA expects the actual emission profile of a source
subject to an appropriately set longer term average limit to be similar
to the emission profile of a source subject to an analogous 1-hour
average limit. EPA expects this similarity because it has recommended
that the longer term average limit be set at a level that is comparably
stringent to the otherwise applicable 1-hour limit (reflecting a
downward adjustment from the critical emissions value) and that takes
the source's emissions profile into account. As a result, EPA expects
either form of emission limit to yield comparable air quality.
    Second, from a more theoretical perspective, EPA has compared the
likely air quality with a source having maximum allowable emissions
under an appropriately set longer term limit, as compared to the likely
air quality with the source having maximum allowable

emissions under the comparable 1-hour limit. In this comparison, in the
1-hour average limit scenario, the source is presumed at all times to
emit at the critical emission level, and in the longer term average
limit scenario, the source is presumed occasionally to emit more than
the critical emission value but on average, and presumably at most
times, to emit well below the critical emission value. In an ``average
year,'' compliance with the 1-hour limit is expected to result in three
exceedance days (i.e., three days with hourly values above 75 ppb) and
a fourth day with a maximum hourly value at 75 ppb. By comparison, with
the source complying with a longer term limit, it is possible that
additional exceedances would occur that would not occur in the 1-hour
limit scenario (if emissions exceed the critical emission value at
times when meteorology is conducive to poor air quality). However, this
comparison must also factor in the likelihood that exceedances that
would be expected in the 1-hour limit scenario would not occur in the
longer term limit scenario. This result arises because the longer term
limit requires lower emissions most of the time (because the limit is
set well below the critical emission value), so a source complying with
an appropriately set longer term limit is likely to have lower
emissions at critical times than would be the case if the source were
emitting as allowed with a 1-hour limit.
    As a hypothetical example to illustrate these points, suppose a
source that always emits 1000 pounds of SO2 per hour, which
results in air quality at the level of the NAAQS (i.e., results in a
design value of 75 ppb). Suppose further that in an ``average year,''
these emissions cause the 5-highest maximum daily average 1-hour
concentrations to be 100 ppb, 90 ppb, 80 ppb, 75 ppb, and 70 ppb. Then
suppose that the source becomes subject to a 30-day average emission
limit of 700 pounds per hour. It is theoretically possible for a source
meeting this limit to have emissions that occasionally exceed 1000
pounds per hour, but with a typical emissions profile emissions would
much more commonly be between 600 and 800 pounds per hour. In this
simplified example, assume a zero background concentration, which
allows one to assume a linear relationship between emissions and air
quality. (A nonzero background concentration would make the mathematics
more difficult but would give similar results.) Air quality will depend
on what emissions happen on what critical hours, but suppose that
emissions at the relevant times on these 5 days are 800 pounds/hour,
1100 pounds per hour, 500 pounds per hour, 900 pounds per hour, and
1200 pounds per hour, respectively. (This is a conservative example
because the average of these emissions, 900 pounds per hour, is well
over the 30-day average emission limit.) These emissions would result
in daily maximum 1-hour concentrations of 80 ppb, 99 ppb, 40 ppb, 67.5
ppb, and 84 ppb. In this example, the fifth day would have an
exceedance that would not otherwise have occurred, but the third and
fourth days would not have exceedances that otherwise would have
occurred. In this example, the fourth highest maximum daily
concentration under the 30-day average would be 67.5 ppb.
    This simplified example illustrates the findings of a more
complicated statistical analysis that EPA conducted using a range of
scenarios using actual plant data. As described in Appendix B of EPA's
2014 SO2 Nonattainment Guidance, EPA found that the
requirement for lower average emissions is highly likely to yield
better air quality than is required with a comparably stringent 1-hour
limit. Based on analyses described in Appendix B of its 2014
SO2 Nonattainment Guidance, EPA expects that an emission
profile with maximum allowable emissions under an appropriately set
comparably stringent 30-day average limit is likely to have the net
effect of having a lower number of exceedances and better air quality
than an emission profile with maximum allowable emissions under a 1-
hour emission limit at the critical emission value. This result
provides a compelling policy rationale for allowing the use of a longer
averaging period, in appropriate circumstances where the facts indicate
this result can be expected to occur.
    The question then becomes whether this approach, which is likely to
produce a lower number of overall exceedances even though it may
produce some unexpected exceedances above the critical emission value,
meets the requirement in section 110(a)(1) and 172(c)(1) for SIPs to
``provide for attainment'' of the NAAQS. For SO2, as for
other pollutants, it is generally impossible to design a nonattainment
plan in the present that will guarantee that attainment will occur in
the future. A variety of factors can cause a well-designed attainment
plan to fail and unexpectedly not result in attainment, for example if
meteorology occurs that is more conducive to poor air quality than was
anticipated in the plan. Therefore, in determining whether a plan meets
the requirement to provide for attainment, EPA's task is commonly to
judge not whether the plan provides absolute certainty that attainment
will in fact occur, but rather whether the plan provides an adequate
level of confidence of prospective NAAQS attainment. From this
perspective, in evaluating use of a 30-day average limit, EPA must
weigh the likely net effect on air quality. Such an evaluation must
consider the risk that occasions with meteorology conducive to high
concentrations will have elevated emissions leading to exceedances that
would not otherwise have occurred, and must also weigh the likelihood
that the requirement for lower emissions on average will result in days
not having exceedances that would have been expected with emissions at
the critical emissions value. Additional policy considerations, such as
in this case the desirability of accommodating real world emissions
variability without significant risk of violations, are also
appropriate factors for EPA to weigh in judging whether a plan provides
a reasonable degree of confidence that the plan will lead to
attainment. Based on these considerations, especially given the high
likelihood that a continuously enforceable limit averaged over as long
as 30 days, determined in accordance with EPA's guidance, will result
in attainment, EPA believes as a general matter that such limits, if
appropriately determined, can reasonably be considered to provide for
attainment of the 2010 SO2 NAAQS.
    The 2014 SO2 Nonattainment Guidance offers specific
recommendations for determining an appropriate longer term average
limit. The recommended method starts with determination of the 1-hour
emission limit that would provide for attainment (i.e., the critical
emission value), and applies an adjustment factor to determine the
(lower) level of the longer term average emission limit that would be
estimated to have a stringency comparable to the otherwise necessary 1-
hour emission limit. This method uses a database of continuous emission
data reflecting the type of control that the source will be using to
comply with the SIP emission limits, which (if compliance requires new
controls) may require use of an emission database from another source.
The recommended method involves using these data to calculate a
complete set of emission averages, computed according to the averaging
time and averaging procedures of the prospective emission limitation.
In this recommended method, the ratio of the 99th percentile among
these long term averages to the 99th percentile of the 1-hour values
represents an adjustment factor that may

be multiplied by the candidate 1-hour emission limit to determine a
longer term average emission limit that may be considered comparably
stringent.\5\ The 2014 SO2 Nonattainment Guidance also
addresses a variety of related topics, such as the potential utility of
setting supplemental emission limits, such as mass-based limits, to
reduce the likelihood and/or magnitude of elevated emission levels that
might occur under the longer term emission rate limit. Preferred air
quality models for use in regulatory applications are described in
Appendix A of EPA's Guideline on Air Quality Models (40 CFR part 51,
Appendix W).\6\ In 2005, EPA promulgated the American Meteorological
Society/Environmental Protection Agency Regulatory Model (AERMOD) as
the Agency's preferred near-field dispersion modeling for a wide range
of regulatory applications addressing stationary sources (for example
in estimating SO2 concentrations) in all types of terrain
based on extensive developmental and performance evaluation.
Supplemental guidance on modeling for purposes of demonstrating
attainment of the SO2 standard is provided in Appendix A to
the April 23, 2014 SO2 nonattainment area SIP guidance
document referenced above. Appendix A provides extensive guidance on
the modeling domain, the source inputs, assorted types of
meteorological data, and background concentrations. Consistency with
the recommendations in this guidance is generally necessary for the
attainment demonstration to offer adequately reliable assurance that
the plan provides for attainment.
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    \5\ For example, if the critical emission value is 1000 pounds
of SO2 per hour, and a suitable adjustment factor is
determined to be 70 percent, the recommended longer term average
limit would be 700 pounds per hour.
    \6\ The EPA published revisions to the Guideline on Air Quality
Models on January 17, 2017.
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    As stated previously, attainment demonstrations for the 2010 1-hour
primary SO2 NAAQS must demonstrate future attainment and
maintenance of the NAAQS in the entire area designated as nonattainment
(i.e., not just at the violating monitor) by using air quality
dispersion modeling (see Appendix W to 40 CFR part 51) to show that the
mix of sources and enforceable control measures and emission rates in
an identified area will not lead to a violation of the SO2
NAAQS. For a short-term (i.e., 1-hour) standard, EPA believes that
dispersion modeling, using allowable emissions and addressing
stationary sources in the affected area (and in some cases those
sources located outside the nonattainment area which may affect
attainment in the area) is technically appropriate, efficient and
effective in demonstrating attainment in nonattainment areas because it
takes into consideration combinations of meteorological and emission
source operating conditions that may contribute to peak ground-level
concentrations of SO2.
    The meteorological data used in the analysis should generally be
processed with the most recent version of AERMET. Estimated
concentrations should include ambient background concentrations, should
follow the form of the standard, and should be calculated as described
in section <IP_ADDRESS> of the August 23, 2010 clarification memo on
``Applicability of Appendix W Modeling Guidance for the 1-hr
SO2 National Ambient Air Quality Standard'' (U. S. EPA,
2010a).

IV. Pennsylvania's Attainment Plan Submittal for the Beaver Area

    In accordance with section 172(c) of the CAA, the Pennsylvania
attainment plan for the Beaver Area includes: (1) An emissions
inventory for SO2 for the plan's base year (2011); (2) an
attainment demonstration including an analysis that locates,
identifies, and quantifies sources of emissions contributing to
violations of the 2010 SO2 NAAQS and a dispersion modeling
analysis of an emissions control strategy for the primary remaining
SO2 sources in the area and which also accounts for smaller
sources within the Area in the background concentration, showing
attainment of the SO2 NAAQS by the October 4, 2018
attainment date; (3) a determination that the control strategy for the
primary remaining SO2 sources within the nonattainment area
constitutes RACM/RACT; (4) requirements for RFP toward attaining the
SO2 NAAQS in the Area; (5) contingency measures; and (6) the
assertion that Pennsylvania's existing SIP-approved NSR program meets
the applicable requirements for SO2. The Pennsylvania
attainment plan for the Beaver Area also includes the request that
emission limitations and compliance parameters contained in a consent
order with Bruce Mansfield and a consent order with Jewel be
incorporated into the SIP.

V. EPA's Analysis of Pennsylvania's Attainment Plan for the Beaver Area

    Consistent with CAA requirements (see section 172), an attainment
demonstration for a SO2 nonattainment area must show that
the area will attain the 2010 SO2 NAAQS as expeditiously as
practicable. The demonstration must also meet the requirements of 40
CFR 51.112 and 40 CFR part 51, Appendix W, and include inventory data,
modeling results, and emissions reductions analyses on which the state
has based its projected attainment. EPA is proposing that the
attainment plan submitted by Pennsylvania is sufficient, and EPA is
proposing to approve the plan to ensure ongoing attainment.

A. Pollutants Addressed

    Pennsylvania's SO2 attainment plan evaluates
SO2 emissions for the Area within the portion of Beaver
County (Industry Borough, Shippingport Borough, Midland Borough,
Brighton Township, Potter Township and Vanport Township) that is
designated nonattainment for the 2010 SO2 NAAQS. There are
no precursors to consider for the SO2 attainment plan.
SO2 is a pollutant that arises from direct emissions, and
therefore concentrations are highest relatively close to the sources
and much lower at greater distances due to dispersion. Thus,
SO2 concentration patterns resemble those of other directly
emitted pollutants like lead, and differ from those of photochemically-
formed (secondary) pollutants such as ozone.

B. Emissions Inventory Requirements

    States are required under section 172(c)(3) of the CAA to develop
comprehensive, accurate and current emissions inventories of all
sources of the relevant pollutant or pollutants in the nonattainment
area. These inventories provide detailed accounting of all emissions
and emissions sources by precursor or pollutant. In addition,
inventories are used in air quality modeling to demonstrate that
attainment of the NAAQS is as expeditious as practicable. The 2014
SO2 Nonattainment Guidance provides that the emissions
inventory should be consistent with the Air Emissions Reporting
Requirements (AERR) at Subpart A to 40 CFR part 51.\7\
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    \7\ The AERR at Subpart A to 40 CFR part 51 cover overarching
federal reporting requirements for the states to submit emissions
inventories for criteria pollutants to EPA's Emissions Inventory
System. EPA uses these submittals, along with other data sources, to
build the National Emissions Inventory.
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    For the base year inventory of actual emissions, a ``comprehensive,
accurate and current'' inventory can be represented by a year that
contributed to the three-year design value used for the original
nonattainment designation. The 2014 SO2 Nonattainment
Guidance notes that the base year inventory should include all sources
of SO2 in the nonattainment area as well as any sources
located outside the nonattainment area which may affect

attainment in the area. Pennsylvania appropriately elected to use 2011
as the base year, as the Area was designated nonattainment with monitor
data from 2009-2011. Actual emissions from all the sources of
SO2 in the Beaver Area were reviewed and compiled for the
base year emissions inventory requirement. One additional source
located outside the area was included in the inventory due to its
proximity to the Area. The source is IPSCO Koppel Tubular (Koppel) with
2011 emissions of 130.42 tons per year (tpy). Table 1 shows the level
of emissions, expressed in tpy, in the Beaver Area for the 2011 base
year by emissions source category. The point source category includes
all sources within the nonattainment area and one source (Koppel) just
outside the area.

   Table 1--2011 Base Year SO2 Emissions Inventory for the Beaver Area
------------------------------------------------------------------------
                                                          SO2  Emissions
                Emission source category                       (tpy)

------------------------------------------------------------------------
Point...................................................      26,591.051
Area....................................................          29.784
Non-road................................................           0.111
On-road.................................................           1.530
                                                         ---------------
    Total...............................................      26,622.476
------------------------------------------------------------------------

                       Table 2--Point Source 2011
                Actual Sulfur Dioxide Emission Inventory
------------------------------------------------------------------------
                                                          SO2  Emissions
                        Facility                               (tpy)

------------------------------------------------------------------------
AES BEAVER VALLEY.......................................       3,085.634
BRUCE MANSFIELD.........................................      21,195.710
HORSEHEAD...............................................       2,014.920
IPSCO KOPPEL TUBULARS/KOPPEL *..........................         130.420
JEWEL...................................................         162.100
SHELL...................................................           0.000
All Other Point Sources Combined........................           2.267
                                                         ---------------
    Total...............................................      26,591.051
------------------------------------------------------------------------
* IPSCO KOPPEL TUBULARS/KOPPEL is not physically in the Beaver Area, but
  modeling shows it has a small impact on it. Another source located
  near the Area, Anchor Hocking/Monaca, which had 2011 SO2 emissions of
  26.068 tons, was also evaluated. Based on the modeling analysis,
  Anchor Hocking/Monaca does not have significant impacts in the Beaver
  Area and is not included in the inventory.

    A more detailed discussion of the emissions inventory for the
Beaver Area can be found in Pennsylvania's September 29, 2017
submittal, as well as, the emissions inventory Technical Support
Document (TSD), which can be found under Docket ID No. EPA-R03-OAR-
2017-0681 and is available online at www.regulations.gov. EPA has
evaluated Pennsylvania's 2011 base year emissions inventory for the
Beaver Area and has made the determination that this inventory was
developed consistently with section 172(c)(3) and EPA's guidance as
discussed in detail in the inventory TSD. Therefore, EPA is proposing
to approve Pennsylvania's 2011 base year emissions inventory for the
Beaver Area.
    The attainment plan also provides for a projected attainment year
inventory that includes estimated emissions for all emission sources of
SO2 which are determined to impact the Beaver Area for the
year in which the area is expected to attain the NAAQS. Pennsylvania
provided a 2018 projected emissions inventory for all known sources
included in the 2011 base year inventory and one additional source,
Shell Chemical Appalachia LLC's recently permitted petrochemicals
complex. This source will not start operation until after 2018 but has
been included to provide assurance that the NAAQS will be attained and
maintained notwithstanding commencement of its operation.
    The projected 2018 emissions are shown in Table 3 and Table 4.
Projected allowable emissions for 2018 exceed the 2011 emissions
inventory; however, projected actual emissions for 2018 are below the
2011 emissions inventory. It should be noted that the sources most
likely causing impacts at the previously violating monitor, including
AES Beaver Valley and Horsehead, have closed or remain idled such as
the Jewel Facility's Meltshop. The remaining primary SO2
sources with their new allowable emissions may be above the total 2011
actual emissions in the Area; however, the remaining primary sources
were modeled using emissions above their new allowable emissions (as
listed in Table 4) and demonstrate attainment as discussed subsequently
in this Notice. SO2 impacts are very source specific and
assumptions cannot be made merely related to the total amount of
emissions in an area. Also, as discussed in the submittal, the
projected actual emissions are based on business projections of 2018
operations, and allowable maximum 2018 emissions are assuming that the
plant is operating 8,760 hours per year and in compliance with the
comparably stringent longer term average limit. The allowable maximum
provides the worst-case emissions for the facilities versus the actual
anticipated emissions which are based on typical operating hours and on
projected business demand. In this case, the modeled maximum
SO2 emissions were not set equal to the allowable maximum
emissions, but were greater than the allowable maximum emissions. For
Bruce Mansfield, the 2018 maximum modeled emissions were 45,038.226
tpy. The 2018 modeled maximum emissions for Koppel and Shell were 306.6
tpy and 22.0 tpy, respectively.
    Reductions in projected 2018 SO2 emissions in the
onroad, nonroad and nonpoint source categories can be attributed to
lower sulfur content limits for gasoline and diesel fuels for the
onroad and nonroad sector, and more stringent sulfur content limits on
home heating oil and other distillate/residual fuel oils for the
nonpoint sector which limits are included in the Pennsylvania SIP. A
detailed discussion of projected emissions for the Beaver Area can be
found in Pennsylvania's September 29, 2017 submittal which can be found
under Docket ID No. EPA-R03-OAR-2017-0681 and online at
www.regulations.gov.

   Table 3--2018 Projected SO2 Emission Inventory for the Beaver Area
------------------------------------------------------------------------
                                                          SO2  emissions
                                                               (tpy)
                                          SO2  emissions     *includes
                                               (tpy)         allowable
        Emission source category            anticipated    emissions for
                                              actual         all point
                                                              sources

------------------------------------------------------------------------
Point...................................      14,679.771      32,420.050
Area....................................          22.586          22.586
Non-road................................           0.057           0.057
On-road.................................           0.590           0.590
                                         -------------------------------
    Total...............................      14,703.004      32,443.283
------------------------------------------------------------------------

   Table 4--2018 Projected Point Source Emissions for the Beaver Area
------------------------------------------------------------------------
                                                               2018
                                               2018         Anticipated
                Facility                  Allowable  Max    Actual SO2
                                            SO2  (tpy)         (tpy)
------------------------------------------------------------------------
AES BEAVER VALLEY.......................           0.000           0.000
BRUCE MANSFIELD.........................      32,245.560      14,542.309
HORSEHEAD...............................           0.000           0.000
IPSCO KOPPEL TUBULARS/KOPPEL *..........         149.500         133.472
JEWEL...................................           1.603           1.603
SHELL **................................          21.000           0.000
All Other Point Sources Combined........           2.387           2.387
                                         -------------------------------
    Total...............................      32,420.050      14,679.771
------------------------------------------------------------------------
* IPSCO KOPPEL TUBULARS/KOPPEL is not physically in the nonattainment
  area, but modeling shows it has a small impact on it. It is included
  in the 2011 base year and 2018 attainment year inventories.
** Shell does not anticipate startup to occur prior to the end of 2018.
  Annual emissions after startup are limited by the facility's Plan
  Approval to less than 21 tons SO2 per year.

C. Air Quality Modeling

    The SO2 attainment demonstration provides an air quality
dispersion modeling analysis to demonstrate that control strategies
chosen to reduce SO2 source emissions will bring the Area
into attainment by the statutory attainment date of October 4, 2018.
The modeling analysis, conducted pursuant to recommendations outlined
in Appendix W to 40 CFR part 51 (EPA's Modeling Guidance), is used for
the attainment demonstration to assess the control strategy for a
nonattainment area and establish emission limits that will provide for
attainment. The analysis requires five years of meteorological data to
simulate the dispersion of pollutant plumes from multiple point, area,
or volume sources across the averaging times of interest. The modeling
demonstration typically also relies on maximum allowable emissions from
sources in the nonattainment area. Though the actual emissions are
likely to be below the allowable emissions, sources have the ability to
run at higher production rates or optimize controls such that emissions
approach the allowable emissions limits. A modeling analysis that
provides for attainment under all scenarios of operation for each
source must therefore consider the worst-case scenario of both the
meteorology (e.g. predominant wind directions, stagnation, etc.) and
the maximum allowable emissions. In this case, the modeled maximum
SO2 emissions were greater than the allowable maximum
SO2 emissions.
    PADEP's modeling analysis was developed in accordance with EPA's
Modeling Guidance and the 2014 SO2 Nonattainment Guidance,
and was prepared using EPA's preferred dispersion modeling system,
AERMOD. A more detailed discussion of PADEP's modeling analysis for the
Beaver Area can be found in Pennsylvania's September 29, 2017 submittal
as well as the modeling TSD, which can be found under Docket ID No.
EPA-R03-OAR-2017-0681 which is available online at www.regulations.gov.
    For its modeling demonstration, PADEP evaluated SO2
emissions from the Bruce Mansfield Facility located in Shippingport
Borough and potential SO2 emissions from Shell Chemical
Appalachia LLC's (Shell Chemical Appalachia) planned petrochemicals
complex to be located in Potter and Center Townships. SO2
emissions from Koppel, located outside the Beaver Area were also
included in the modeling. The Jewel Facility Meltshop was idled in 2015
and its emissions were not included in the attainment modeling
demonstration. To resume operation, the Meltshop must comply with a
Consent Order and Agreement (COA) described in section D of this
notice.
    EPA has reviewed the modeling that Pennsylvania submitted to
support the attainment demonstration for the Beaver Area and has
determined that this modeling is consistent with CAA requirements,
Appendix W, and EPA's Guidance for SO2 attainment
demonstration modeling. The modeling properly characterized source
limits, local meteorological data, background concentrations, and
provided an adequate model receptor grid to capture maximum modeled
concentrations. Using the EPA conversion factor for the SO2
NAAQS, the modeled design values for the Beaver Area are less than 75
ppb as shown in Table 5 below.\8\ EPA's analysis of the modeling is
discussed in

more detail in EPA's modeling TSD, which can be found under Docket ID
No. EPA-R03-OAR-2017-0681. EPA proposes to conclude that the modeling
provided in the attainment plan shows that the Beaver Area will attain
the 2010 1-hour primary SO2 NAAQS by the attainment date and
proposes to approve the attainment demonstration.
---------------------------------------------------------------------------

    \8\ The SO2 NAAQS level is expressed in ppb but
AERMOD gives results in micrograms per meter cubed ([mu]g/m\3\). The
conversion factor for SO2 (at the standard conditions
applied in the ambient SO2 reference method) is 1ppb =
approximately 2.619 [mu]g/m\3\. See Pennsylvania's SO2
Round 3 Designations Proposed Technical Support Document at https://www.epa.gov/sites/production/files/2017-08/documents/35_pa_so2_rd3-final.pdf.
---------------------------------------------------------------------------

D. RACM/RACT

    CAA section 172(c)(1) requires that each attainment plan provide
for the implementation of all RACM as expeditiously as practicable for
attainment of the NAAQS. EPA interprets RACM, including RACT, under
section 172, as measures that a state determines to be both reasonably
available and contribute to attainment as expeditiously as practicable
``for existing sources in the area.'' In addition, CAA section
172(c)(6) requires plans to include enforceable emission limitations
and control measures as may be necessary or appropriate to provide for
attainment by the attainment date.
    Pennsylvania's September 29, 2017 submittal discusses federal and
state measures that will provide emission reductions leading to
attainment and maintenance of the 2010 SO2 NAAQS. With
regards to state rules, Pennsylvania cites its low sulfur fuel rules,
which were SIP-approved on July 10, 2014 (79 FR 39330). Pennsylvania's
low sulfur fuel oil provisions apply to refineries, pipelines,
terminals, retail outlet fuel storage facilities, commercial and
industrial facilities, and facilities with units burning regulated fuel
oil to produce electricity and domestic home heaters. These low sulfur
fuel oil rules reduce the amount of sulfur in fuel oils used in
combustion units, thereby reducing SO2 emissions and the
formation of sulfates that cause decreased visibility.
    Pennsylvania's attainment plan submittal discusses facility
closures and facility-specific control measures. Pennsylvania's
submittal indicates that two of the three largest sources in the Beaver
Area were permanently shut down prior to January 2, 2017. The Horsehead
facility closed in the spring of 2014 and has been demolished. AES
Beaver Valley was a coal fired power plant that permanently shut down
in the fall of 2015. Appendix A of the state submittal includes PADEP's
approval letters of Emission Reduction Credits for these facilities
which indicate permanent facility closure. The Jewel Facility is
currently idled and has agreed in a Consent Order and Agreement with
PADEP that its Meltshop cannot emit any SO2 emissions unless
additional modeling is done to support attainment and new
SO2 emissions limitations are established for the SIP as
necessary. This restriction is established in a COA (see Appendix C of
the September 29, 2017 submittal) between PADEP and the Jewel Facility
which PADEP seeks to have incorporated by reference into the SIP,
thereby making it permanently federally enforceable under the CAA. In
addition to these actual emission reductions in the Area of 5,100.554
tpy, new SO2 emission limits were developed through air
dispersion modeling (AERMOD) submitted by PADEP as discussed below, and
in section IV.C. Air Quality Modeling of this proposed rulemaking as
well as in the modeling TSD.
    In order to ensure that the Beaver Area demonstrates attainment
with the SO2 NAAQS, PADEP asserts that the following
combination of emission limits at the Bruce Mansfield Facility are
sufficient for the Beaver Area to meet the SO2 NAAQS and
serve as RACM/RACT. For the Bruce Mansfield Facility, the new emission
limits are established in a COA (see Appendix C of the September 29,
2017 submittal) between PADEP and FirstEnergy for the Bruce Mansfield
Facility, which PADEP has also submitted for incorporation into the SIP
as permanently federally enforceable limits under the CAA.
    The Facility's SO2 emission sources include three coal-
fired boilers (Unit 1, Unit 2, and Unit 3) that were included in the
air dispersion modeling. The SO2 emissions from each of the
three boilers are controlled by three individual Flue Gas
Desulfurization (FGD) systems. Unit 1 and Unit 2 each vent through two
flues within a common stack. Unit 3 vents through two flues in the
other stack. To demonstrate compliance with the 2010 1-hour
SO2 NAAQS, FirstEnergy requested that the Unit 1 and Unit 2
combined emission limit be established as a function of the Unit 3
emission limit. On and after October 1, 2018, FirstEnergy shall begin
calculating a pound per hour (lb/hr) 30-operating day rolling average
SO2 emission rate for Unit 1 (Source ID 031) and Unit 2
(Source ID 032) from Chimney 1 (Stacks S01-S04), and a lb/hr 30-
operating day rolling average SO2 emission rate for Unit 3
(Source ID 033) from Chimney 2 (Stacks S05 and S06), using data from
the PADEP-certified Continuous Emission Monitoring Systems (CEMS) at
the Bruce Mansfield Facility. The 30-operating day rolling average
SO2 emissions rates shall be calculated using the procedures
outlined in the Mercury and Air Toxics Standards (MATS) regulations in
40 CFR parts 60 and 63. The 30-operating day rolling average
SO2 emissions rate for Units 1 and 2 cannot exceed the
result of equation one (EQ-1), below, with Chimney 1 (CH1) and Chimney
2 (CH2) in service, calculated daily. In addition, the 30-operating day
rolling average emissions rate cannot exceed 7,362 lb/hr for Units 1
and 2 combined. The 30-operating day rolling average SO2
emissions rate cannot exceed 3,584 lb/hr for Unit 3. The results of EQ-
1 are only valid when Unit 3 emissions are less than or equal to 3,584
lb/hr.

EQ-1: CH1SO2 Lim = -1.38E-04 x CH2SO2\2\ - 0.920
x CH2SO2 + 7100

Where:

CH1SO2 Lim: Chimney 1 SO2 lb/hr 30-day rolling
average Limit
CH1SO2 Lim <=7,362 lb/hr
CH2SO2: Chimney 2 SO2 lb/hr 30-day rolling
average.
CH2SO2 <=3,584 lb/hr

    Also, FirstEnergy is required by the COA to use its PADEP-certified
CEMS to demonstrate compliance with the new emission restrictions as
detailed in the COA (Paragraph 3.a. of the COA). In accordance with the
current version of PADEP's Continuous Source Monitoring Manual,
FirstEnergy is required by the COA to continue to provide quarterly
reports of emissions data as recorded by the CEMS to PADEP.
    Additionally, FirstEnergy shall achieve as detailed in the COA at
least a 95% removal efficiency from the FGDs following the general
requirements contained in 25 Pa. Code Chapter 139.11. FirstEnergy shall
annually test for removal efficiency of the FGDs by using a combination
of CEMS data and coal sampling in accordance with the procedures
outlined in 40 CFR part 60, Appendix A, Method 19. Three test runs
shall be conducted concurrently in the two flues that feed each unit
during the annual tests. Each test run shall be a minimum of sixty
minutes in duration. A report of the efficiency test shall be provided
annually to PADEP. The first report shall be submitted within one (1)
year of the final execution of this COA and annually thereafter.
FirstEnergy shall maintain records of the operation of and emissions
monitoring from the FGDs, including the annual efficiency report.
    The auxiliary boilers located at the Bruce Mansfield Facility are
limited by an existing federally enforceable operating permit to a
capacity factor of less than 5% in any 12-consecutive month period.
PADEP stated this existing federally enforceable limitation has reduced
the potential to emit SO2 to levels at which additional
SO2 controls are not feasible. Thus PADEP concluded the
permit restrictions are RACM and no

further control is needed from these auxiliary boilers for the Area to
attain the NAAQS or to reflect RACT from these boilers. EPA finds
Pennsylvania's conclusion for the auxiliary boilers reasonable given
the existing permit limitations and low potential to emit
SO2.
    Operating restrictions are also placed on the Jewel Facility as
RACM/RACT. To ensure that the Beaver Area will demonstrate attainment
with the 2010 1-hour SO2 NAAQS, the Jewel Facility has
agreed to conditions in a COA which specifies zero SO2
emissions from the Meltshop, which is the Jewel Facility Source ID 106.
Other SO2 emission sources at the facility were addressed in
the modeling analysis as part of the ``background'' sources as
discussed in section V. C. of this notice. The COA also requires
additional modeling and SO2 emission limitations for the SIP
as necessary to assure attainment before the Jewel Facility would be
able to operate the Meltshop. EPA is proposing here to approve the
requirement for zero emissions from the Meltshop as RACM/RACT; any
authorization of nonzero emissions from this Meltshop source would need
to be subject to EPA review as a SIP revision with required modeling
analysis showing continued attainment of the NAAQS.
    Based on the modeling analysis discussed in section V.C. Air
Quality Modeling above, the collective emission limits and related
compliance parameters for the Bruce Mansfield Facility, along with the
operating restrictions at the Jewel Facility, have been proposed as
RACM/RACT and for incorporation into the SIP, therefore making them
federally enforceable. PADEP asserts that this proposed control
strategy as demonstrated by the modeling analysis is sufficient for the
Beaver Area to attain the 2010 SO2 NAAQS.
    To establish the emission limit equation (EQ-1) described earlier
in this section, Pennsylvania conducted a modeling analysis that
included eleven modeling runs, supplemented with six additional
modeling runs performed by FirstEnergy, to determine the range of
emission rates for the three Units at the Bruce Mansfield Facility that
provide for attainment. In each of these runs, the model demonstrates
that the respective set of hourly emissions would result in the 5-year
average of the 99th percentile of daily maximum hourly SO2
concentrations below the level of the 1-hour NAAQS. The modeling
results are presented in Table 5.

 Table 5--Summary of Air Dispersion Modeling Results for FirstEnergy Bruce Mansfield 1-Hour SO2 Modeled Emission
                                                     Values
----------------------------------------------------------------------------------------------------------------
                                                                                Maximum
                                                                                modeled
                                                                   Unit 1 & unit      Unit 3        1[dash]hour
                            Model run                             2 combined  1-    1[dash]hour     SO2 design
                                                                   hour SO2 rate   SO2 rate (lb/   concentration
                                                                      (lb/hr)           hr)         ([micro]g/
                                                                                m\3\)
----------------------------------------------------------------------------------------------------------------
1...............................................................       10,282.70            0.00       196.17563
2...............................................................        9,254.43          761.19       196.18089
3...............................................................        8,226.16        1,482.72       196.17966
1FE *...........................................................        7,484.24        2,006.14       196.18033
4...............................................................        7,197.89        2,206.62       196.17977
2FE *...........................................................        6,765.97        2,507.57       196.14426
5...............................................................        6,169.62        2,885.44       196.18044
3FE *...........................................................        5,952.47        3,009.17       196.07897
6...............................................................        5,141.35        3,469.90       196.17912
4FE *...........................................................        5,051.66        3,510.68       196.11106
7...............................................................        4,113.08        3,985.46       196.17974
5FE *...........................................................        4,015.93        4,012.20       196.04158
8...............................................................        3,084.81        4,407.53       196.18032
6FE *...........................................................        2,857.18        4,513.72       196.10031
9...............................................................        2,056.54        4,743.88       196.18082
10..............................................................        1,028.27        4,956.43       196.18081
11..............................................................            0.00        5,041.58       196.17832
----------------------------------------------------------------------------------------------------------------
* FirstEnergy model run.

    FirstEnergy developed adjustment factors to convert the 1-hour
emission rates (Table 5) to comparably stringent 30-operating day
emission rates for each unit at the Bruce Mansfield Facility. To do
this, historic operating data for 2012-2016 from EPA's Clean Air
Markets Database (CAMD) were used in accordance with the methods EPA
recommended in Appendix C and Appendix D of EPA's 2014 SO2
Nonattainment Guidance. The SO2 emission limit adjustment
factor was calculated as 0.59 for Unit 1, 0.717 for Unit 2, and 0.794
for Unit 3. The adjustment factor for Unit 2 was applied to Unit 1 as
First Energy deemed it a more representative correction factor for Unit
1. It was noted in Pennsylvania's submittal that Unit 2's hourly
emissions have a tendency to be higher more frequently than Unit 1.
Given this fact, Pennsylvania asserted that applying the adjustment
factor developed for Unit 2 (higher frequency of higher emissions) to
Unit 1 will continue to protect the NAAQS. EPA's SO2
Nonattainment Guidance allows for using a unit more representative of
planned operations going forward under the newly established emission
limits stating ``. . . data from other sources of comparable source
type, size, operation, fuel, and control type may be more useful for
these comparisons.'' In addition, Unit 2's adjustment factors of 0.717
is very similar to the average adjustment factor for 30-day emission
values (0.71) listed in Appendix D of EPA's SO2
Nonattainment Guidance for sources with wet scrubbers (the same control
technology that Unit 1 and 2 have in place). For these reasons, EPA
believes it is appropriate to utilize 0.717 as the adjustment factor
for Unit 1.
    The unit specific adjustment factors (0.717 for Units 1 and 2, and
0.794 for Unit 3) were multiplied by the 1-hour modeled emission rates
shown in Table 5, resulting in the corresponding 30-day average
emission rates shown in

columns three and five in Table 6. These corresponding 30-day average
emission rates show a series of 30-day average limits for Units 1 and 2
combined emissions and for Unit 3 emissions, respectively. Pennsylvania
then determined an equation (EQ-1), identified above, that can be used
to interpolate additional combinations of emissions that would also
result in attainment.
    Table 6 addresses the relationship between the modeling results and
Pennsylvania's emission limit in particular addressing whether the
modeling demonstrates that Pennsylvania's compliance equation provides
for attainment throughout the range of possible combinations of
allowable emissions. For each model run, Table 6 shows the modeled
emission rates for Units 1 + 2 (reflecting the sum of emissions from
the two units) and for Unit 3, along with the corresponding 30-day
average emission rates. EPA calculated the sixth column of Table 6 by
plugging in the Unit 3 30-day average emission rates (from the fifth
column, Table 6) into the equation, and determining the limit for Units
1 and 2. In three cases, the entry in the sixth column is
``Disallowed,'' because the emission rate for Unit 3 is higher than the
30-operating day average limit (3,584 lbs/hr) that independently
applies to Unit 3. An important feature of Table 6 is that the limit on
the sum of emissions from Units 1 and 2 computed using the equation
(EQ-1), in all cases is lower than the 30-day average sum of Units 1
and 2 emissions that was calculated as comparably stringent to the
modeled 1-hour sum of Units 1 and 2 emissions. For a full range of
cases, Pennsylvania demonstrated that its equation required a level of
emissions that is lower than the level (adjusted to reflect comparable
stringency) demonstrated to result in attainment. In other words, the
equation (EQ-1) used to calculate the 30-day average limits is slightly
more stringent than the comparably stringent adjusted 30-day average
limits. By this means, Pennsylvania demonstrated that the compliance
equation that it adopted, supplemented by independent limits on the
emissions of Unit 3 and on the sum of emissions from Units 1 and 2,
provides for attainment.

                     Table 6--FirstEnergy Bruce Mansfield 30-Day Average SO2 Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                                                30-day average
                                                                                SO2 limit for
                                   Modeled      Corresponding                   Corresponding  units 1 + 2 based
                                emissions for  30-day average      Modeled     30-day average  on 30-day average
          Model run              units 1 + 2    emissions for   emissions for   emissions for    equivalent to
                                   (lb/hr)       units 1 + 2   unit 3 (lb/hr)  unit 3 (lb/hr)    modeled unit 3
                                                 (lb/hr) **                          **        emissions (lb/hr)
                                                                                ***
----------------------------------------------------------------------------------------------------------------
1............................       10,282.70        7,372.70            0.00            0.00             7100.0
2............................        9,254.43        6,635.43          761.19          604.38             6493.6
3............................        8,226.16        5,898.16        1,482.72        1,177.28             5825.6
1FE *........................        7,484.24        5,366.20        2,006.14        1,592.88             5284.4
4............................        7,197.89        5,160.89        2,206.62        1,752.06             5064.5
2FE *........................        6,765.97        4,851.20        2,507.57        1,991.01             4721.2
5............................        6,169.62        4,323.62        2,885.44        2,291.04             4267.9
3FE *........................        5,952.47        4,267.92        3,009.17        2,389.28             4114.1
6............................        5,141.35        3,686.35        3,469.90        2,755.10             3517.8
4FE *........................        5,051.66        3,622.04        3,510.68        2,787.48             3463.3
7............................        4,113.08        2,949.08        3,985.46        3,164.46             2806.8
5FE *........................        4,015.93        2,879.42        4,012.20        3,185.69             2768.7
8............................        3,084.81        2,211.81        4,407.53        3,499.58             2190.3
6FE *........................        2,857.18        2,048.60        4,513.72        3,583.89             2030.3
9............................        2,056.54        1,474.54        4,743.88        3,766.64         Disallowed
10...........................        1,028.27          737.27        4,956.43        3,935.41         Disallowed
11...........................            0.00            0.00        5,041.58        4,003.01         Disallowed
----------------------------------------------------------------------------------------------------------------
* FirstEnergy model run.
** Corresponding 30-day average emission rates were calculated by multiplying the modeled 1-hour emission rates
  from Table 5 by PADEP's adjustment ratios (0.717 for Units 1 and 2; 0.794 for Unit 3).
*** The limit that would result from the compliance equation (EQ-1) using the Unit 3 30-operating day average
  emission rate that corresponds to the modeled 1-hour rate (from fifth column of this table).

    EPA's guidance for longer term average limits states that plans
based on such limits can be considered to provide for attainment where
appropriate as long as the longer term limit is comparably stringent to
the 1-hour limit that would otherwise be set, and as long as EPA can
have reasonable confidence that occasions of emissions above the CEV
will be limited in frequency and magnitude. To address this latter
criterion, Pennsylvania has provided an analysis of historic emissions,
assessing the frequency of elevated emissions. This analysis used 2012-
2016 CAMD data. Pennsylvania established a limit based on an equation
involving the emissions from multiple units. The equation was derived
from the modeled CEV values (from Table 5). These values were used to
develop a polynomial equation which was plotted on a graph and compared
to the 2012-2016 CAMD data. This comparison demonstrates that during
2012-2016, the Bruce Mansfield Facility only exceeded the 1 hour
emissions formula for 0.50% of the hours.\9\ PADEP's CEV analysis is

provided in an excel spreadsheet in the Docket at www.regulations.gov.
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    \9\ Appendix E-1 of Pennsylvania's September 29, 2017 submittal
included a statement that ``[p]rior to the implementation of the new
emissions limits associated with the 2010 standard, the occasions
when emissions have exceeded the proposed CEVs have been relatively
few. In fact, it has only occurred 13% of the time during the period
of 2012-2016.'' Pennsylvania submitted a correction to this
statement and the corresponding emissions analysis on June 11, 2018
via email which is included in Docket ID No. EPA-R03-OAR-2017-0681.
EPA has reviewed the correction and agrees with the assessment.
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    Accordingly, EPA believes that PADEP has demonstrated that its
limit for the Bruce Mansfield facility will assure that occasions of
emissions exceeding critical levels will be limited. More generally,
EPA believes that PADEP has met EPA's recommended criteria for longer
term average limits and believes that the emission limits proposed by
PADEP for the Bruce Mansfield Facility will provide reasonable
assurance that the Area will attain the standard.
    Additional information on the development of the adjustment factor
and limits, including statistical analyses performed to develop the
limits in accordance with the 2014 SO2 Nonattainment
Guidance, can be found in Section IV: Control Strategies and in
Appendices D and E of the Pennsylvania attainment plan submittal of
September 29, 2017. These adjustment factors are reasonably consistent
with the average adjustment factor identified in Appendix D of the 2014
SO2 Nonattainment Guidance for units controlled with wet
FGDs (an adjustment factor of 0.71). EPA reviewed the modeling which
shows the Beaver Area attaining the NAAQS with these limits at the
Bruce Mansfield Facility and reviewed the methodology used to develop
the 30-operating day limits and agrees that the limits are reasonable
and follow EPA's 2014 SO2 Nonattainment Guidance. EPA is
proposing to approve the emission limits for the Bruce Mansfield
Facility Units 1, 2 and 3 as representing RACM/RACT.
    EPA finds that the proposed SO2 control strategy at the
Bruce Mansfield Facility and Jewel Facility, the only remaining
significant SO2 sources in the Area after the closure of
Horsehead and AES Beaver Valley, constitute RACM/RACT for sources in
the Beaver Area based on the modeling analysis previously described
which demonstrates the Beaver Area is projected to attain the
SO2 NAAQS by the 2018 attainment date. Furthermore, with our
final approval of Pennsylvania's attainment plan, the emission limits
described for the three units at the Bruce Mansfield Facility and
corresponding compliance parameters found in the COA for the Bruce
Mansfield Facility as well as the operating restrictions on the Jewel
Facility will become permanent and enforceable SIP measures to meet the
requirements of the CAA. EPA proposes that Pennsylvania has satisfied
the requirements in CAA sections 172(c)(1) and 172(c)(6) to adopt and
submit all RACM and enforceable emission limitations and control
measures as needed to attain the standard as expeditiously as
practicable.

E. RFP Plan

    Section 172(c)(2) of the CAA requires that an attainment plan
includes a demonstration that shows reasonable further progress (i.e.,
RFP) for meeting air quality standards will be achieved through
generally linear incremental improvement in air quality. Section 171(1)
of the CAA defines RFP as ``such annual incremental reductions in
emissions of the relevant air pollutant as are required by this part
(part D) or may reasonably be required by EPA for the purpose of
ensuring attainment of the applicable NAAQS by the applicable
attainment date.'' As stated originally in the 1994 SO2
Guidelines Document \10\ and repeated in the 2014 SO2
Nonattainment Guidance, EPA continues to believe that this definition
is most appropriate for pollutants that are emitted from numerous and
diverse sources, where the relationship between particular sources and
ambient air quality are not directly quantified. In such cases,
emissions reductions may be required from various types and locations
of sources. The relationship between SO2 and sources is much
more defined, and usually there is a single step between pre-control
nonattainment and post-control attainment. Therefore, EPA interpreted
RFP for SO2 as adherence to an ambitious compliance schedule
in both the 1994 SO2 Guideline Document and the 2014
SO2 Nonattainment Guidance. The control measures for
attainment of the 2010 SO2 NAAQS included in Pennsylvania's
submittal have been modeled to achieve attainment of the NAAQS. The
SO2 emission reductions from the permanent shutdowns at
Horsehead and AES Beaver Valley along with the COAs including specific
emission limits and compliance parameters which are effective at the
Bruce Mansfield Facility on October 1, 2018, and operating restrictions
on the Jewel Facility effective on October 1, 2018, show the resulting
emission reductions to be achieved as expeditiously as practicable for
the Area. EPA guidance recommends a compliance date of January 1, 2017
for purposes of providing for a calendar year of meeting the standard,
however in this plan some sources in the area did not have any
emissions for several years while other sources still in operation such
as the Bruce Mansfield and Jewel facilities will have new limits
effective October 1, 2018. However, air quality data in this area has
shown attainment of the NAAQS since 2015. Also based on air quality
modeling reviewed by EPA, the new limits and shutdowns result in
modeled attainment of the SO2 NAAQS for the Beaver Area.
Therefore, EPA has determined that PADEP's SO2 attainment
plan for the Beaver Area fulfills the RFP requirements for the Area.
EPA does not anticipate future nonattainment, or that the Area will not
meet the October 4, 2018 attainment date. EPA proposes to approve
Pennsylvania's attainment plan with respect to the RFP requirements.
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    \10\ SO2 Guideline Document, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, EPA-452/R-94-008, February 1994.
Located at: http://www.epa.gov/ttn/oarpg/t1pgm.html.
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F. Contingency Measures

    In accordance with section 172(c)(9) of the CAA, contingency
measures are required as additional measures to be implemented in the
event that an area fails to meet the RFP requirements or fails to
attain the standard by its attainment date. These measures must be
fully adopted rules or control measures that can be implemented quickly
and without additional EPA or state action if the area fails to meet
RFP requirements or fails to meet its attainment date, and should
contain trigger mechanisms and an implementation schedule. However,
SO2 presents special considerations. As stated in the final
2010 SO2 NAAQS promulgation on June 22, 2010 (75 FR 35520)
and in the 2014 SO2 Nonattainment Guidance, EPA concluded
that because of the quantifiable relationship between SO2
sources and control measures, it is appropriate that state agencies
develop a comprehensive program to identify sources of violations of
the SO2 NAAQS and undertake an aggressive follow-up for
compliance and enforcement.
    The Bruce Mansfield Facility COA (see Appendix C of the September
29, 2017 submittal) contains the following measures that are designed
to keep the Area from triggering an exceedance or violation of the
SO2 NAAQS: (1) If the SO2 emissions from Units 1,
2 or 3 exceed 99% of the limits set forth in paragraph 3A of the COA,
FirstEnergy shall, within 48 hours, begin a full system audit of Units
1, 2, and 3 SO2 controls. The audit shall document the
operating parameters of the sources and their control devices and
evaluate whether the units and control devices were operating
effectively. If the units and/or control devices were not operating
effectively, FirstEnergy shall

identify corrective actions to be implemented to ensure that the limits
in Paragraph 3(a) of the COA are not exceeded. Only one audit in a
seven operating day period is required if SO2 emissions from
Units 1, 2, and 3 exceed 99% of the limits in Paragraph 3(a) of the
COA. The audit shall be documented and records maintained on site, and
a report documenting the audit provided to PADEP within 45 days of
completing the audit. (2) At any time after October 1, 2018, if any
PADEP SO2 monitor within the Beaver Area measures a 1-hour
concentration exceeding 75 ppb, PADEP will notify the Jewel Facility,
Koppel, Shell, and FirstEnergy in writing. A 1-hour SO2
concentration that exceeds 75 ppb at any PADEP SO2 monitor
in the Beaver Area will be a ``daily exceedance.'' FirstEnergy shall
identify whether Unit 1, Unit 2, and/or Unit 3 were running at the time
of the exceedance and within a reasonable time period leading up to the
exceedance. If Unit 1, Unit 2, and/or Unit 3 were running at the time
of the exceedance, and within a reasonable time period leading up to
the exceedance, FirstEnergy shall perform an analysis of meteorological
data on the day the daily exceedance occurred to ensure that the daily
exceedance was not due to SO2 emissions from that source.
The meteorological data analysis may include trajectories run at three
different heights (one at stack height and two more within the boundary
layer) by NOAA's Hysplit program or an equivalent program, hourly
meteorological data collected at the FirstEnergy Beaver Valley nuclear
power station to determine stability parameters within the river
valley, and/or an analysis of Pittsburgh International Airport's
radiosonde data and modeled upper air data. The overall goal of the
meteorological data analysis is to investigate if emissions from the
source could have potentially mixed down to the SO2 monitor
measuring the exceedance. The source's finding must be submitted in
writing to PADEP within 45 days of PADEP notifying FirstEnergy. These
measures will be incorporated into the Pennsylvania SIP upon EPA's
final approval of this attainment plan.
    There is also one contingency measure pertaining to the Jewel
Facility. According to the COA with the facility, if the Jewel Facility
Meltshop is reactivated and if any of PADEP's monitors in the Beaver
Area measure a 1-hour SO2 concentration of 75 ppb or
greater, PADEP will notify the Jewel Facility both verbally and in
writing. The Jewel Facility shall notify PADEP of the operational
status of the Meltshop within 10 days of the notice.
    Additionally, PADEP states in its attainment plan that if PADEP
identifies a 1-hour daily maximum concentration at a PADEP operated
SO2 ambient air quality monitor in the Beaver Area that
registers a concentration exceeding 75 ppb, PADEP would proceed with
the following actions and enforcement as appropriate: (1) Within 5
business days, the PADEP Bureau of Air Quality Monitoring Division will
contact the Air Resource Management Division Chief and the Southwest
Regional Office (SWRO) Air Program Manager to report the monitored
value. (2) Within 5 business days, SWRO staff will contact FirstEnergy
and the Jewel Facility, if reactivated, to trigger the implementation
of their contingency measures found in the COAs. If necessary, section
4(27) of the Pennsylvania Air Pollution Control Act (APCA), 35 P.S.
Sec.  4004(27), authorizes PADEP to take any action it deems necessary
or proper for the effective enforcement of the APCA and the rules and
regulations promulgated under the APCA. Such actions include the
issuance of orders (i.e., enforcement orders and orders to take
corrective action to address air pollution or the danger of air
pollution from a source) and the assessment of civil penalties. A more
detailed description of the contingency measures can be found in
section VIII of the September 27, 2017 submittal as well as in the COAs
included in the submittal and included for incorporation by reference
into the SIP.
    EPA is proposing to find that Pennsylvania's September 29, 2017
submittal includes sufficient measures to expeditiously identify the
source of any violation of the SO2 NAAQS and for aggressive
follow-up including enforcement measures within PADEP's authority under
the APCA as necessary. Therefore, EPA proposes that the contingency
measures submitted by Pennsylvania follow the 2014 SO2
Nonattainment Guidance and meet the section 172(c)(9) requirements.

G. New Source Review \11\
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    \11\ The CAA new source review (NSR) program is composed of
three separate programs: Prevention of significant deterioration
(PSD), Nonattainment NSR (NNSR), and Minor NSR. PSD is established
in part C of title I of the CAA and applies in undesignated areas
and areas that meet the NAAQS-- designated ``attainment areas''--as
well as areas where there is insufficient information to determine
if the area meets the NAAQS--designated ``unclassifiable areas.''
The NNSR program is established in part D of title I of the CAA and
applies in areas that are not in attainment of the NAAQS --
``nonattainment areas.'' The Minor NSR program addresses
construction or modification activities that do not qualify as
``major'' and applies regardless of the designation of the area in
which a source is located. Together, these programs are referred to
as the NSR programs. Section 173 of the CAA lays out the NNSR
program for preconstruction review of new major sources or major
modifications to existing sources, as required by CAA section
172(c)(5). The programmatic elements for NNSR include, among other
things, compliance with the lowest achievable emissions rate and the
requirement to obtain emissions offsets.
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    Section 172(c)(5) of the CAA requires that an attainment plan
require permits for the construction and operation of new or modified
major stationary sources in a nonattainment area. Pennsylvania has a
fully implemented Nonattainment New Source Review (NNSR) program for
criteria pollutants in 25 Pennsylvania Code Chapter 127, Subchapter E,
which was originally approved into the Pennsylvania SIP on December 9,
1997 (62 FR 64722). On May 14, 2012 (77 FR 28261), EPA approved a SIP
revision pertaining to the pre-construction permitting requirements of
Pennsylvania's NNSR program to update the regulations to meet EPA's
2002 NSR reform regulations. EPA then approved an update to
Pennsylvania's NNSR regulations on July 13, 2012 (77 FR 41276). These
rules provide for appropriate new source review as required by CAA
sections 172(c)(5) and 173 and 40 CFR 51.165 for SO2 sources
undergoing construction or major modification in the Beaver Area
without need for modification of the approved rules. Therefore, EPA
concludes that the Pennsylvania SIP meets the requirements of section
172(c)(5) for this Area.

VI. EPA's Proposed Action

    EPA is proposing to approve Pennsylvania's SIP revision, its
attainment plan for the Beaver Area, as submitted through PADEP to EPA
on September 29, 2017, for the purpose of demonstrating attainment of
the 2010 1-hour SO2 NAAQS. Specifically, EPA is proposing to
approve the base year emissions inventory, a modeling demonstration of
SO2 attainment, an analysis of RACM/RACT, an RFP plan, and
contingency measures for the Beaver Area and is proposing that the
Pennsylvania SIP has met requirements for NSR for the 2010 1-hour
SO2 NAAQS. Additionally, EPA is proposing to approve into
the Pennsylvania SIP specific SO2 emission limits and
compliance parameters and control measures established for the
SO2 sources impacting the Beaver Area.
    EPA has determined that Pennsylvania's SO2 attainment
plan for the 2010 1-hour SO2 NAAQS for Beaver

County meets the applicable requirements of the CAA and EPA's 2014
SO2 Nonattainment Guidance. Thus, EPA is proposing to
approve Pennsylvania's attainment plan for the Beaver Area as submitted
on September 29, 2017. EPA's analysis for this proposed action is
discussed in Section V of this proposed rulemaking. EPA is soliciting
public comments on the issues discussed in this document. These
comments will be considered before taking final action. Final approval
of this SIP submittal will remove EPA's duty to promulgate and
implement a FIP for this Area.

VII. Incorporation by Reference

    In this document, EPA is proposing to include regulatory text in a
final rule that includes incorporation by reference. In accordance with
requirements of 40 CFR 51.5, EPA is proposing to incorporate by
reference the portions of the COAs entered between Pennsylvania and
FirstEnergy and Pennsylvania and Jewel included in the PADEP submittal
of September 29, 2017 that are not redacted. This includes emission
limits and associated compliance parameters, recording-keeping and
reporting, and contingency measures. EPA has made, and will continue to
make, these materials generally available through http://www.regulations.gov and at the EPA Region III Office (please contact
the person identified in the FOR FURTHER INFORMATION CONTACT section of
this preamble for more information).

VIII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely approves state law as meeting federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this proposed rule, concerning the SO2
attainment plan for the Beaver nonattainment area in Pennsylvania, does
not have tribal implications as specified by Executive Order 13175 (65
FR 67249, November 9, 2000), because the SIP is not approved to apply
in Indian country located in the state, and EPA notes that it will not
impose substantial direct costs on tribal governments or preempt tribal
law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Reporting and recordkeeping requirements, Sulfur oxides.

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

    Dated: September 24, 2018.
Cosmo Servidio,
Regional Administrator, Region III.
[FR Doc. 2018-21667 Filed 10-4-18; 8:45 am]
BILLING CODE 6560-50-P