[Federal Register Volume 89, Number 29 (Monday, February 12, 2024)]
[Proposed Rules]
[Pages 9815-9819]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-02834]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 81

[EPA-R03-OAR-2023-0419; FRL-11736-01-R3]


Redesignation of Portions of Westmoreland and Cambria Counties, 
Pennsylvania for the 2010 Sulfur Dioxide (SO2) National Ambient Air 
Quality Standards (NAAQS): Notification of Availability and Public 
Comment Period

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability and public comment period.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA or the Agency) is 
providing notice of our intent to redesignate portions of Westmoreland 
County and Cambria County, Pennsylvania, to ``nonattainment'' for the 
2010 sulfur dioxide (SO<INF>2</INF>) national ambient air quality 
standard (NAAQS or standard). Westmoreland County is currently 
designated ``attainment/unclassifiable,'' and Cambria County is 
currently designated ``unclassifiable.'' EPA's intended redesignation 
of portions of these counties is based on modeled violations of the 
2010 SO<INF>2</INF> NAAQS. If the redesignation to nonattainment is 
finalized, the Commonwealth of Pennsylvania would be required to 
undertake certain planning requirements to reduce SO<INF>2</INF> 
concentrations within this area, including, but not limited to, the 
requirement to submit within 18 months of redesignation a revision to 
the Pennsylvania state implementation plan (SIP) that provides for 
attainment of the SO<INF>2</INF> standard as expeditiously as 
practicable, but no later than five years after the date of 
redesignation to nonattainment.
    Notice is hereby given that EPA has posted on our public electronic 
docket and internet website the intended redesignation for relevant 
portions of Westmoreland and Cambria counties, Pennsylvania under the 
2010 SO<INF>2</INF> NAAQS. The Agency invites the public to review and 
provide input on our intended redesignation during the comment period 
specified in the DATES section. EPA notified the Commonwealth of 
Pennsylvania of our intended redesignation action via a letter to the 
Governor on or about February 17, 2023, which is included in the docket 
for this notice of availability (NOA).

DATES: Comments must be received on or before March 28, 2024. Please 
refer to

[[Page 9816]]

the SUPPLEMENTARY INFORMATION section for additional information on the 
comment period.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-
OAR-2023-0419 at www.regulations.gov or via email to 
<a href="/cdn-cgi/l/email-protection#bed9d1ccdad1d090d3d7d5dbfedbcedf90d9d1c8"><span class="__cf_email__" data-cfemail="e5828a97818a8bcb888c8e80a5809584cb828a93">[email protected]</span></a>. 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 www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: For general questions concerning this 
action, please contact Ellen Schmitt, Planning & Implementation Branch 
(3AD30), Air & Radiation Division, U.S. Environmental Protection 
Agency, Region III, 1600 John F. Kennedy Boulevard, Philadelphia, 
Pennsylvania 19103. The telephone number is (215) 814-5787. Ms. Schmitt 
can also be reached via electronic mail at <a href="/cdn-cgi/l/email-protection#7f0c1c1712160b0b511a13131a113f1a0f1e51181009"><span class="__cf_email__" data-cfemail="6310000b0e0a17174d060f0f060d230613024d040c15">[email protected]</span></a>.
    EPA encourages the public to review our letter notifying 
Pennsylvania of our intended redesignation action, and the associated 
area-specific technical support information at www.epa.gov/sulfur-dioxide-designations/sulfur-dioxide-designations-regulatory-actions or 
in the public docket for this intended redesignation at 
www.regulations.gov under Docket ID No. EPA-R03-OAR-2023-0419.

SUPPLEMENTARY INFORMATION: 
    The information in this document is organized as follows:

I. Purpose of Action and Instructions for Submitting Public Comments
II. The 2010 SO<INF>2</INF> NAAQS
III. Designations for the 2010 SO<INF>2</INF> NAAQS
IV. SO<INF>2</INF> Monitoring and Modeling Considerations
V. Modeled SO<INF>2</INF> NAAQS Violations in Westmoreland and 
Cambria Counties, Pennsylvania
VI. EPA's Intended Decision To Address Modeled SO<INF>2</INF> NAAQS 
Violations in Portions of Westmoreland and Cambria Counties, 
Pennsylvania Through Redesignation

I. Purpose of Action and Instructions for Submitting Public Comments

    The purpose of this NOA is to solicit input from interested parties 
on EPA's notification to the Governor of Pennsylvania about our intent 
and rationale for redesignating portions of Westmoreland and Cambria 
counties in Pennsylvania to nonattainment for the 2010 SO<INF>2</INF> 
NAAQS. EPA's notification letter and the supporting technical analysis 
can be found at www.epa.gov/sulfur-dioxide-designations/sulfur-dioxide-designations-regulatory-actions, as well as in the public docket for 
this redesignation at www.regulations.gov under Docket ID No. EPA-R03-
OAR-2023-0419.
    EPA invites public input regarding the redesignation of portions of 
Westmoreland and Cambria counties during the 45-day comment period 
provided in this document. To receive full consideration, input from 
the public must be submitted to the docket by March 28, 2024. This 
publication and opportunity for public comment does not affect any 
rights or obligations of any state, or tribe, or of EPA, which might 
otherwise exist pursuant to the Clean Air Act (CAA or Act) section 
107(d).
    CAA section 107(d)(3) provides a process for air quality 
redesignations that involves recommendations by affected states, 
territories, and tribes to EPA and responses from the Agency to those 
parties, prior to EPA promulgating final area redesignation decisions. 
The Agency is not required under CAA section 107(d)(3) to seek public 
comment during the redesignations process, but we are electing to do so 
for these counties with respect to the 2010 SO<INF>2</INF> NAAQS to 
gather additional information for EPA to consider before making a final 
redesignation decision for these specific areas.

A. Submitting CBI

    Do not submit CBI information to EPA through www.regulations.gov or 
email. Clearly mark the part or all of the information that you claim 
to be CBI. For CBI on a disk or CD-ROM that you mail to EPA, mark the 
outside of the disk or CD-ROM as CBI and then identify electronically 
within the disk or CD-ROM the specific information that is claimed as 
CBI. In addition to one complete version of the comment that includes 
information claimed as CBI, a copy of the comment that does not contain 
the information claimed as CBI must be submitted for inclusion in the 
public docket. Information so marked will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2. For additional directions on sending or delivering 
information identified as CBI, contact the person identified in the FOR 
FURTHER INFORMATION CONTACT section.

B. Tips for Preparing Your Comments

    When submitting comments, remember to:
    <bullet> Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
    <bullet> Follow directions.
    <bullet> Explain why you agree or disagree; suggest alternatives 
and substitute language for your requested changes.

II. The 2010 SO2 NAAQS

    Under section 109 of the CAA, EPA has established primary and 
secondary NAAQS for certain pervasive air pollutants (referred to as 
``criteria pollutants'') and conducts periodic reviews of the NAAQS to 
determine whether they should be revised or whether new NAAQS should be 
established. The primary NAAQS represent ambient air quality standards, 
the attainment and maintenance of which EPA has determined, including a 
margin of safety, are requisite to protect the public health. The 
secondary NAAQS represent ambient air quality standards, the attainment 
and maintenance of which EPA has determined are requisite to protect 
the public welfare from any known or anticipated adverse effects 
associated with the presence of such air pollutant in the ambient air.
    EPA revised the primary SO<INF>2</INF> NAAQS in a final rule 
published in the Federal Register on June 22, 2010 (75 FR 35520), 
codified at 40 CFR 50.17, which became effective on August 23, 2010. 
Based on review of the air quality criteria for oxides of sulfur and 
the primary NAAQS for oxides of sulfur as measured by SO<INF>2,</INF> 
EPA revised the primary SO<INF>2</INF> NAAQS to provide the requisite 
protection of public health with an adequate margin of safety. 
Specifically, EPA established a new 1-hour SO<INF>2</INF> standard at a 
level of 75 parts per billion (ppb), which is met at an ambient air 
quality monitoring site (or in the case of dispersion modeling, at an 
ambient air

[[Page 9817]]

quality receptor location) when the 3-year average of the annual 99th 
percentile of daily maximum 1-hour average concentrations is less than 
or equal to 75 ppb, as determined in accordance with appendix T of 40 
CFR part 50. 40 CFR 50.17(a) and (b).
    Anthropogenic SO<INF>2</INF> emissions originate chiefly from point 
sources, with fossil fuel combustion at electric utilities and other 
industrial facilities accounting for the majority of total 
emissions.\1\ Current scientific evidence links short-term exposures to 
SO<INF>2</INF>, ranging from five minutes to 24 hours, with an array of 
adverse respiratory effects including bronchoconstriction and increased 
asthma symptoms.\2\ These effects are particularly important for 
asthmatics at elevated ventilation rates (e.g., while exercising or 
playing).\3\ Studies also show a connection between short-term exposure 
and increased visits to emergency departments and hospital admissions 
for respiratory illnesses, particularly in at-risk populations 
including children, the elderly and asthmatics.\4\
---------------------------------------------------------------------------

    \1\ 75 FR 35520 (June 22, 2010).
    \2\ Id.
    \3\ Id.
    \4\ Id.
---------------------------------------------------------------------------

III. Designations for the 2010 SO2 NAAQS

    EPA is required by CAA section 107(d) to designate all areas 
throughout the nation as attaining or not attaining the NAAQS within 
two years of the promulgation of any new or revised NAAQS. Pursuant to 
CAA section 107(d), EPA must designate as ``nonattainment'' those areas 
that violate the NAAQS and those nearby areas that contribute to 
violations. Once an area has been designated, the EPA Administrator, 
under CAA section 107(d)(3), may at any time notify a state that a 
designation should be revised.
    EPA was required to designate areas throughout the country for the 
2010 SO<INF>2</INF> NAAQS by June 3, 2012. EPA invoked a 1-year 
extension of the deadline to designate areas for the 2010 
SO<INF>2</INF> NAAQS, as provided for under CAA section 107, after 
which the Agency completed an initial round of SO<INF>2</INF> 
designations for certain areas of the country on August 5, 2013 
(referred to as ``Round 1'').\5\ In Round 1, EPA designated Indiana 
County and a portion of Armstrong County, Pennsylvania as nonattainment 
(hereafter referred to as the ``Indiana Area''). On January 9, 2018,\6\ 
in a subsequent round of designations (Round 3), EPA designated 
Westmoreland County, Pennsylvania as attainment/unclassifiable, and 
Cambria County, Pennsylvania as unclassifiable.
---------------------------------------------------------------------------

    \5\ 78 FR 47191. Effective date October 4, 2013.
    \6\ 83 FR 1098. Effective date April 9, 2018.
---------------------------------------------------------------------------

    In 2018, during the public comment period for the proposed approval 
of the SO<INF>2</INF> attainment SIP for the Indiana Area (83 FR 32606, 
July 13, 2018), the Sierra Club (in conjunction with the National Parks 
Conservation Association (NPCA), PennFuture, Earthjustice, and Clean 
Air Council (the Council)) submitted a modeling analysis which claimed 
to show violations of the SO<INF>2</INF> NAAQS within portions of 
Westmoreland and Cambria counties due to SO<INF>2</INF> emissions from 
sources located within the Indiana Area. In 2022, during the public 
comment period for the proposed partial disapproval and partial 
approval of the Indiana Area's attainment SIP (87 FR 15166, March 17, 
2022), EPA received additional modeling from the Sierra Club, and 
Keystone-Conemaugh Projects, LLC (KEY-CON),\7\ focused on the 
Westmoreland and Cambria areas. EPA also conducted its own modeling of 
those areas. Based on review of all modeling analyses, EPA has 
determined that there are modeled SO<INF>2</INF> NAAQS violations 
outside of the existing Indiana Area, in portions of Westmoreland and 
Cambria counties, and accordingly notified the Governor of Pennsylvania 
in a letter dated February 17, 2023, of its intent to redesignate the 
relevant portions of Westmoreland and Cambria counties as nonattainment 
for the 2010 SO<INF>2</INF> NAAQS, consistent with CAA section 
107(d)(3)(A). On June 22, 2023, Acting Secretary for the Pennsylvania 
Department of Environmental Protection (PA DEP), Richard Negrin, 
responded to EPA's letter but did not specify whether the Commonwealth 
agreed or disagreed with EPA's determination to redesignate portions of 
Westmoreland and Cambria counties as nonattainment for the 2010 
SO<INF>2</INF> NAAQS. Instead, Pennsylvania's response included several 
comments questioning certain aspects of the Technical Support Document 
(TSD) that EPA had developed and submitted to PA DEP with the February 
17, 2023 redesignation letter. EPA has responded to the Commonwealth's 
comments in a response to comments (RTC) document which is in the 
docket for this document.\8\
---------------------------------------------------------------------------

    \7\ KEY-CON, licensee for the Keystone Generating Station 
located in Armstrong County and the Conemaugh Generating station 
located in Indiana County, provided modeling to support its comments 
rebutting modeling and views presented by the Sierra Club and EPA.
    \8\ A copy of PA DEP's comments on EPA's initial redesignation 
TSD and also EPA's RTC replying to these comments, can be found in 
Docket No. EPA-R03-OAR-2023-0419 via www.regulations.gov.
---------------------------------------------------------------------------

IV. SO2 Monitoring and Modeling Considerations

    The 1-hour primary SO<INF>2</INF> standard is violated at an 
ambient air quality monitoring site (or in the case of dispersion 
modeling, at an ambient air quality receptor location) when the 3-year 
average of the annual 99th percentile of the daily maximum 1-hour 
average concentrations exceeds 75 ppb, as determined in accordance with 
appendix T of 40 CFR part 50. EPA also believes that in certain cases, 
including when SO<INF>2</INF> monitors are lacking, air dispersion 
modeling is an appropriate tool to determine whether an area is in 
attainment, as discussed in EPA's document titled, ``SO<INF>2</INF> 
NAAQS Designations Modeling Technical Assistance Document'' (Modeling 
TAD). The Modeling TAD provides nonbinding recommendations on how to 
appropriately and sufficiently model ambient air in proximity to an 
SO<INF>2</INF> emission source to establish air quality data for 
comparison to the 2010 primary SO<INF>2</INF> NAAQS for the purposes of 
designations.
    Ambient SO<INF>2</INF> monitoring data are collected by state, 
local, and tribal monitoring agencies (``monitoring agencies'') in 
accordance with the monitoring requirements contained in 40 CFR parts 
50, 53, and 58. A monitoring network is generally designed to measure, 
report, and provide related information on air quality data as 
described in 40 CFR part 58. To ensure that the data from the network 
is accurate and reliable, the monitors in the network must meet a 
number of requirements, including the use of monitoring methods that 
EPA has approved as Federal Reference Methods (FRMs) or Federal 
Equivalent Methods (FEMs), focusing on particular monitoring 
objectives, and following specific siting criteria, data reporting, 
quality assurance and data handling rules or procedures.
    At present, except for SO<INF>2</INF> monitoring required at 
National Core Monitoring Stations (Ncore stations), there are no 
minimum monitoring requirements for SO<INF>2</INF> in 40 CFR part 58 
appendix D, other than a requirement for EPA Regional Administrator 
approval before removing any existing monitors and a requirement that 
any ongoing SO<INF>2</INF> monitoring must have at least one monitor 
sited to measure the maximum concentration of SO<INF>2</INF> in that 
area.
    In addition to using any valid data generated by existing monitors, 
refined dispersion modeling may inform NAAQS designation and

[[Page 9818]]

implementation decisions regarding sources that may have the potential 
to cause or contribute to a NAAQS violation. For a short-term 1-hour 
standard, dispersion modeling of stationary sources can be more 
technically appropriate, efficient, and effective because it accounts 
for fairly infrequent combinations of meteorological and source 
operating conditions that can contribute to peak ground-level 
concentrations of SO<INF>2</INF>.
    EPA's Guideline on Air Quality Models, found at appendix W to 40 
CFR part 51, provides recommendations on modeling techniques and 
guidance for estimating pollutant concentrations to assess control 
strategies and determine emission limits.

V. Modeled SO2 NAAQS Violations in Westmoreland and Cambria Counties, 
Pennsylvania

    Effective on October 4, 2013, the Indiana Area (which encompasses 
Indiana County, as well as Plumcreek Township, South Bend Township and 
Eldertown Borough of Armstrong County) was designated as nonattainment 
for the 2010 SO<INF>2</INF> NAAQS. The Indiana Area includes Keystone, 
Conemaugh, Homer City, and Seward electric generating units (EGUs), all 
primary SO<INF>2</INF> emitting sources.
    On October 11, 2017, PA DEP submitted to EPA an attainment SIP for 
the Indiana Area which the Agency proposed approval of on July 13, 2018 
(83 FR 32606). During the public comment period for the proposed 
approval of the attainment SIP, the Sierra Club (in conjunction with 
the NPCA, PennFuture, Earthjustice, and the Council) submitted a 
modeling analysis using actual emissions and the critical emission 
values (CEVs) \9\ for Conemaugh and Seward which claimed to show 
violations of the SO<INF>2</INF> NAAQS outside of the Indiana Area, 
beyond the eastern border of Indiana County, within nearby portions of 
Westmoreland and Cambria counties. The modeling used the same 
meteorological data, stack parameters, background concentrations and 
building downwash as Pennsylvania's attainment SIP for the Indiana 
Area. The Sierra Club modeling used emission inputs of actual 
historical emissions (2013-2018 quarter 1) and a finer receptor grid 
that included receptors outside Indiana County. When modeling 2015-2017 
emissions, the resulting design value was 293.4 micrograms per cubic 
meter (ug/m\3\), and when modeling 2013-2017 emissions, the resulting 
design value was 267.2 ug/m\3\.\10\
---------------------------------------------------------------------------

    \9\ A CEV is the maximum modeled emission rate that results in 
attainment.
    \10\ EPA considers 196.4 ug/m\3\ equivalent to 75 ppb (based on 
the 2010 SO<INF>2</INF> NAAQS).
---------------------------------------------------------------------------

    EPA issued a final approval of Pennsylvania's attainment plan for 
the Indiana Area 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 EPA's final approval of the Indiana Area's 
attainment plan.\11\ On April 5, 2021, EPA filed a motion for voluntary 
remand without vacatur of its approval of the Indiana Area attainment 
plan in order to reconsider its approval of the attainment plan.
---------------------------------------------------------------------------

    \11\ Sierra Club, et. al. v. EPA, Case No. 20-3568 (3rd Cir.).
---------------------------------------------------------------------------

    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 2010 SO<INF>2</INF> NAAQS attainment plan for the 
Indiana Area, requiring that the Agency 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 18, 2022).
    After reconsideration, on March 17, 2022, EPA proposed partial 
disapproval and partial approval of the Indiana Area attainment plan 
(87 FR 15166). During the public comment period, EPA received air 
quality modeling (including modeling files) from the Sierra Club (in 
conjunction with the NPCA, PennFuture, Earthjustice, and the Council) 
using updated emissions data claiming to show modeled NAAQS violations 
in Westmoreland and Cambria counties due to SO<INF>2</INF> emissions 
from the Conemaugh and Seward sources located in Indiana County. EPA 
also received an air quality modeling report from KEYCON which used 
updated emissions from Conemaugh and Seward but did not show modeled 
NAAQS violations in Westmoreland and Cambria counties.\12\
---------------------------------------------------------------------------

    \12\ KEYCON emailed the modeling files to EPA on April 20, 2022.
---------------------------------------------------------------------------

    EPA then conducted its own modeling analysis, discussed in detail 
in the TSD located in the docket for this document. Based on review of 
all modeling analyses, EPA determined that there are modeled 
SO<INF>2</INF> NAAQS violations outside of the existing Indiana Area, 
in Westmoreland and Cambria counties.

VI. EPA's Intended Decision To Address Modeled SO2 NAAQS Violations in 
Portions of Westmoreland and Cambria Counties, Pennsylvania Through 
Redesignation

    The CAA provides EPA with the authority to revise designations of, 
or ``redesignate,'' areas under CAA section 107(d)(3). Such 
redesignations can originate as requests by states (per CAA section 
107(d)(3)(D)), and EPA can also notify a state at any time that a 
designation of any area or portion of an area should be revised, on the 
basis of air quality data, planning and control considerations, or any 
other air quality-related considerations the EPA Administrator deems 
appropriate. CAA section 107(d)(3)(A) further states that, ``[i]n 
issuing such notification, which shall be public, to the Governor, the 
Administrator shall provide such information as the Administrator may 
have available explaining the basis for the notice.'' The Act then 
requires the Governor to submit to EPA such redesignation, if any, as 
the Governor deems appropriate (CAA section 107(d)(3)(B)). CAA section 
107(d)(3)(C) states that ``the Administrator shall promulgate the 
redesignation, if any, of the area or portion thereof, submitted by the 
Governor in accordance with [CAA section 107(d)(3)(B)], making such 
modifications as the Administrator may deem necessary . . . . If the 
Governor does not submit, in accordance with [CAA section 
107(d)(3)(B)], a redesignation for an area (or portion thereof) 
identified by the Administrator under [CAA section 107(d)(3)(A)], the 
Administrator shall promulgate such redesignation, if any, that the 
Administrator deems appropriate.''
    As noted, CAA section 107(d)(3)(A) provides EPA latitude to 
consider a broad range of information in considering whether a 
designation should be revised. In consideration of ``air quality data, 
planning and control considerations, or any other air quality-related 
considerations the EPA Administrator deems appropriate,'' EPA has taken 
note of the analytical guidance that it has previously used in issuing 
initial area designations under CAA section 107(d)(1). EPA has issued 
multiple guidance documents for performing SO<INF>2</INF> designations, 
the most recent of which is a September 5, 2019 guidance from Peter 
Tsirigotis, Director, U.S. EPA, Office of Air Quality Planning and 
Standards, to Regional Air Division Directors, U.S. EPA Regions 1-
10.\13\

[[Page 9819]]

This memorandum supplements, where necessary, prior designations 
guidance documents on area designations for the 2010 primary 
SO<INF>2</INF> NAAQS issued on March 24, 2011, March 20, 2015, and July 
22, 2016. The September 2019 memorandum identifies evaluation factors 
in determining whether areas are in violation of the 2010 
SO<INF>2</INF> NAAQS and factors that EPA intends to assess in 
determining the boundaries for such areas. These factors include:
---------------------------------------------------------------------------

    \13\ See, ``Area Designations for the 2010 Primary Sulfur 
Dioxide National Ambient Air Quality Standard--Round 4,'' memorandum 
to Regional Air Division Directors, Regions 1-10, from Peter 
Tsirigotis, dated September 5, 2019, available at www.epa.gov/sites/default/files/2019-09/documents/round_4_so2_designations_memo_09-05-2019_final.pdf.
---------------------------------------------------------------------------

    (1) Air quality characterization via ambient monitoring or 
dispersion modeling results;
    (2) emissions-related data;
    (3) meteorology;
    (4) geography and topography; and
    (5) jurisdictional boundaries.
    Available modeling indicates that portions of Westmoreland and 
Cambria counties are violating the 2010 1-hour SO<INF>2</INF> NAAQS. 
EPA's detailed evaluation of the modeled violations, contributing 
sources, and intended area boundaries based on the weight of evidence 
of the previously identified factors are included in the TSD, which is 
located in the docket for this action. EPA's intended boundaries of the 
relevant area encompass Lower Yoder Township in Cambria County, 
Pennsylvania and St. Clair Township, Seward Borough, and New Florence 
Borough in Westmoreland County, Pennsylvania. A map showing the 
boundaries of our intended nonattainment area for Westmoreland and 
Cambria counties is included in the TSD.
    With respect to area boundaries, EPA's modeling shows that the 
sources of this nonattainment are SO<INF>2</INF> emissions from the 
Conemaugh and Seward plants, which are located in the existing Indiana, 
Pennsylvania nonattainment area. The attainment plan for the Indiana 
Area was partially disapproved and partially approved. This initiated a 
sanctions clock under CAA section 179, providing for emission offset 
sanctions for new sources unless Pennsylvania submits, and EPA fully 
approves, a revised attainment SIP for the Indiana Area within 18 
months after the Agency's final partial disapproval, and providing for 
highway funding sanctions if EPA has not fully approved a revised plan 
within six months thereafter. Due to this unique situation and the 
already determined attainment planning schedule for the Indiana Area, 
EPA has decided not to add the proposed Westmoreland and Cambria 
nonattainment area into the existing Indiana Area. EPA maintains that 
under the circumstances presented here, a new nonattainment area that 
does not include the contributing sources is not an impediment to the 
Commonwealth's ability to impose new emission limits on the sources 
contributing to the air quality violations in the nonattainment area. 
In any future attainment plan submitted for this new area, Pennsylvania 
will need to demonstrate that any future emissions or new emission 
limits for Seward and Conemaugh are sufficient to provide for NAAQS 
attainment in both areas as a result of this redesignation. A 
discussion of the intended boundaries for the Westmoreland and Cambria 
nonattainment area is located in the TSD associated with this 
redesignation document. The TSD can be found at www.regulations.gov in 
Docket ID No. EPA-R03-OAR-2023-0419. Based on this information, EPA 
notified the Governor of Pennsylvania, in a letter dated February 17, 
2023, of EPA's intention to redesignate portions of Westmoreland and 
Cambria counties to nonattainment. On June 22, 2023, Acting Secretary 
for the PA DEP, Richard Negrin, responded to EPA's letter but did not 
specify whether it agreed or disagreed with EPA's determination to 
redesignate portions of Westmoreland and Cambria counties as 
nonattainment for the 2010 SO<INF>2</INF> NAAQS. Instead, 
Pennsylvania's response included several comments questioning certain 
aspects of the TSD that EPA had developed and submitted to PA DEP with 
the February 17, 2023 redesignation letter. EPA has responded to the 
Commonwealth's comments in a RTC document which is in the docket for 
this action.\14\
---------------------------------------------------------------------------

    \14\ A copy of PA DEP's comments on EPA's initial redesignation 
TSD and also EPA's RTC replying to these comments, can be found in 
Docket No. EPA-R03-OAR-2023-0419 via www.regulations.gov.
---------------------------------------------------------------------------

    Through this action, EPA is providing notice of our intent to 
redesignate portions of Westmoreland and Cambria counties to 
nonattainment for the 2010 SO<INF>2</INF> NAAQS. The Agency is 
voluntarily taking public comment on the intended redesignation, TSD, 
and our response to PA DEP's June 27, 2023 comments. Public comment 
information is located in section I of this document. Per CAA section 
107(d)(3)(C), EPA intends to promulgate a redesignation, if any, after 
considering any further information obtained during the comment period.

Adam Ortiz,
Regional Administrator, Region III.
[FR Doc. 2024-02834 Filed 2-9-24; 8:45 am]
BILLING CODE 6560-50-P


</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>