[Federal Register Volume 87, Number 35 (Tuesday, February 22, 2022)]
[Proposed Rules]
[Pages 9516-9533]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-02952]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

EPA-R03-OAR-2021-0873; EPA-HQ-OAR-2021-0663; FRL-9494-01-R3]


Air Plan Disapproval; West Virginia; Interstate Transport of Air 
Pollution for the 2015 8-Hour Ozone National Ambient Air Quality 
Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or the Act), the 
Environmental Protection Agency (EPA) is proposing to disapprove a 
State Implementation Plan (SIP) submittal from West Virginia intended 
to address interstate transport for the 2015 8-hour ozone national 
ambient air quality standards (2015 8-hour ozone NAAQS). The ``good 
neighbor'' or ``interstate

[[Page 9517]]

transport'' provisions require that each state's SIP contain adequate 
provisions to prohibit emissions from within the state from 
significantly contributing to nonattainment or interfering with 
maintenance of the NAAQS in other states. This requirement is part of 
the broader set of ``infrastructure'' requirements, which are designed 
to ensure that the structural components of each state's air quality 
management program are adequate to meet the state's responsibilities 
under the CAA. This disapproval, if finalized, will establish a 2-year 
deadline for the EPA to promulgate a Federal Implementation Plan (FIP) 
to address the relevant interstate transport requirements, unless the 
EPA approves a subsequent SIP submittal that meets these requirements. 
Disapproval does not start a mandatory sanctions clock.

DATES: Written comments must be received on or before April 25, 2022.

ADDRESSES: You may send comments, identified as Docket No. EPA-R03-OAR-
2021-0873, by any of the following methods: Federal eRulemaking Portal 
at https://www.regulations.gov following the online instructions for 
submitting comments or via email to [email protected]. For additional 
methods for submitting comments, contact the person in the FOR FURTHER 
INFORMATION CONTACT section. Include Docket ID No. EPA-R03-OAR-2021-
0873 in the subject line of the message.
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document. Out 
of an abundance of caution for members of the public and our staff, the 
EPA Docket Center and Reading Room are open to the public by 
appointment only to reduce the risk of transmitting COVID-19. Our 
Docket Center staff also continues to provide remote customer service 
via email, phone, and webform. For further information on EPA Docket 
Center services and the current status, please visit us online at 
https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Michael Gordon, Planning & 
Implementation Branch (3AD30), Air & Radiation Division, U.S. 
Environmental Protection Agency, Region III, 1650 Arch Street, 
Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-
2039. Mr. Gordon can also be reached via electronic mail at 
[email protected].

SUPPLEMENTARY INFORMATION: Public Participation: Submit your comments, 
identified by Docket ID No. EPA-R03-OAR-2021-0873, at https://www.regulations.gov (our preferred method), or the other methods 
identified in the ADDRESSES section. Once submitted, comments cannot be 
edited or removed from the docket. The EPA may publish any comment 
received to its public docket. Do not submit to EPA's docket at https://www.regulations.gov 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. The 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).
    There are two dockets supporting this action, EPA-R03-OAR-2021-0873 
and EPA-HQ-OAR-2021-0663. Docket No. EPA-R03-OAR-2021-0873 contains 
information specific to West Virginia, including the notice of proposed 
rulemaking. Docket No. EPA-HQ-OAR-2021-0663 contains additional 
modeling files, emissions inventory files, technical support documents, 
and other relevant supporting documentation regarding interstate 
transport of emissions for the 2015 8-hour ozone NAAQS which are being 
used to support this action. All comments regarding information in 
either of these dockets are to be made in Docket No. EPA-R03-OAR-2021-
0873. For additional submission methods, please contact Michael Gordon, 
215-814-2039, [email protected]. For the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. Due to public health 
concerns related to COVID-19, the EPA Docket Center and Reading Room 
are open to the public by appointment only. Our Docket Center staff 
also continues to provide remote customer service via email, phone, and 
webform. For further information and updates on EPA Docket Center 
services, please visit us online at https://www.epa.gov/dockets.
    The EPA continues to carefully and continuously monitor information 
from the Centers for Disease Control and Prevention (CDC), local area 
health departments, and our Federal partners so that we can respond 
rapidly as conditions change regarding COVID-19. The index to the 
docket for this action, Docket No. EPA-R03-OAR-2021-0873, is available 
electronically at www.regulations.gov. While all documents in the 
docket are listed in the index, some information may not be publicly 
available via the online docket, such as modeling data files, due to 
docket file size restrictions or content (e.g., CBI). Please contact 
the EPA Docket Center Services for further information on how to obtain 
these files.
    Throughout this document, ``we,'' ``us,'' and ``our'' means the 
EPA.

I. Background

A. Description of Statutory Background

    On October 1, 2015, the EPA promulgated a revision to the ozone 
NAAQS (2015 8-hour ozone NAAQS), lowering the level of both the primary 
and secondary standards to 0.070 parts per million (ppm).\1\ Section 
110(a)(1) of the CAA requires states to submit, within 3 years after 
promulgation of a new or revised standard, SIP submissions meeting the 
applicable requirements of section 110(a)(2).\2\ One of these 
applicable requirements is found in CAA section 110(a)(2)(D)(i)(I), 
otherwise known as the ``interstate transport'' or ``good neighbor'' 
provision, which generally requires SIPs to contain adequate provisions 
to prohibit in-state emissions activities from having certain adverse 
air quality effects on other states due to interstate transport of 
pollution. There are two so-called ``prongs'' within CAA section 
110(a)(2)(D)(i)(I). A SIP for a new or revised NAAQS must contain 
adequate provisions prohibiting any source or other type of emissions 
activity within the state from emitting air pollutants in amounts that 
will significantly contribute to nonattainment of the NAAQS in another 
state (prong 1) or interfere with maintenance of the NAAQS in another 
state (prong 2). The EPA and states must give independent

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significance to prong 1 and prong 2 when evaluating downwind air 
quality problems under CAA section 110(a)(2)(D)(i)(I).\3\
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    \1\ National Ambient Air Quality Standards for Ozone, Final 
Rule, 80 FR 65292 (October 26, 2015). Although the level of the 
standard is specified in the units of ppm, ozone concentrations are 
also described in parts per billion (ppb). For example, 0.070 ppm is 
equivalent to 70 ppb.
    \2\ SIP revisions that are intended to meet the applicable 
requirements of section 110(a)(1) and (2) of the CAA are often 
referred to as infrastructure SIPs and the applicable elements under 
section 110(a)(2) are referred to as infrastructure requirements.
    \3\ See North Carolina v. EPA, 531 F.3d 896, 909-11 (D.C. Cir. 
2008).
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B. Description of the EPA's Four-Step Interstate Transport Regulatory 
Process

    The EPA is using the 4-step interstate transport framework (or 4-
step framework) to evaluate the states' SIP submittals addressing the 
interstate transport provision for the 2015 8-hour ozone NAAQS. The EPA 
has addressed the interstate transport requirements of CAA section 
110(a)(2)(D)(i)(I) with respect to prior ozone NAAQS in several 
regional regulatory actions, including the Cross-State Air Pollution 
Rule (CSAPR), which addressed interstate transport with respect to the 
1997 ozone NAAQS as well as the 1997 and 2006 fine particulate matter 
standards,\4\ and the Cross-State Air Pollution Rule Update (CSAPR 
Update) \5\ and the Revised CSAPR Update, both of which addressed the 
2008 ozone NAAQS.\6\
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    \4\ See Federal Implementation Plans: Interstate Transport of 
Fine Particulate Matter and Ozone and Correction of SIP Approvals, 
76 FR 48208 (August 8, 2011).
    \5\ Cross-State Air Pollution Rule Update for the 2008 Ozone 
NAAQS, 81 FR 74504 (October 26, 2016).
    \6\ In 2019, the D.C. Circuit Court of Appeals remanded the 
CSAPR Update to the extent it failed to require upwind states to 
eliminate their significant contribution by the next applicable 
attainment date by which downwind states must come into compliance 
with the NAAQS, as established under CAA section 181(a). Wisconsin 
v. EPA, 938 F.3d 303, 313 (D.C. Cir. 2019). The Revised CSAPR Update 
for the 2008 Ozone NAAQS, 86 FR 23054 (April 30, 2021), responded to 
the remand of the CSAPR Update in Wisconsin and the vacatur of a 
separate rule, the ``CSAPR Close-Out,'' 83 FR 65878 (December 21, 
2018), in New York v. EPA, 781 F. App'x. 4 (D.C. Cir. 2019).
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    Through the development and implementation of the CSAPR rulemakings 
and prior regional rulemakings pursuant to the interstate transport 
provision,\7\ the EPA, working in partnership with states, developed 
the following 4-step interstate transport framework to evaluate a 
State's obligations to eliminate interstate transport emissions under 
the interstate transport provision for the ozone NAAQS: (1) Identify 
monitoring sites that are projected to have problems attaining and/or 
maintaining the NAAQS (i.e., nonattainment and/or maintenance 
receptors); (2) identify states that impact those air quality problems 
in other (i.e., downwind) states sufficiently such that the states are 
considered ``linked'' and therefore warrant further review and 
analysis; (3) identify the emissions reductions necessary (if any), 
applying a multifactor analysis, to eliminate each linked upwind 
state's significant contribution to nonattainment or interference with 
maintenance of the NAAQS at the locations identified in Step 1; and (4) 
adopt permanent and enforceable measures needed to achieve those 
emissions reductions.
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    \7\ In addition to the CSAPR rulemakings, other regional 
rulemakings addressing ozone transport include the ``NOX 
SIP Call,'' 63 FR 57356 (October 27, 1998), and the ``Clean Air 
Interstate Rule'' (CAIR), 70 FR 25162 (May 12, 2005).
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C. Background on the EPA's Ozone Transport Modeling Information

    In general, the EPA has performed nationwide air quality modeling 
to project ozone design values which are used in combination with 
measured data to identify nonattainment and maintenance receptors. To 
quantify the contribution of emissions from specific upwind states on 
2023 ozone design values for the identified downwind nonattainment and 
maintenance receptors, the EPA performed nationwide, state-level ozone 
source apportionment modeling for 2023. The source apportionment 
modeling provided contributions to ozone at receptors from precursor 
emissions of anthropogenic nitrogen oxides (NOX) and 
volatile organic compounds (VOCs) in individual upwind states.
    The EPA has released several documents containing projected ozone 
design values, contributions, and information relevant to evaluating 
interstate transport with respect to the 2015 8-hour ozone NAAQS. 
First, on January 6, 2017, the EPA published a notice of data 
availability (NODA) in which we requested comment on preliminary 
interstate ozone transport data including projected ozone design values 
(DVs) and interstate contributions for 2023 using a 2011 base year 
platform.\8\ In the NODA, the EPA used the year 2023 as the analytic 
year for this preliminary modeling because that year aligns with the 
expected attainment year for Moderate ozone nonattainment areas for the 
2015 8-hour ozone NAAQS.\9\ On October 27, 2017, we released a 
memorandum (October 2017 memorandum) containing updated modeling data 
for 2023, which incorporated changes made in response to comments on 
the NODA, and noted that the modeling may be useful for states 
developing SIPs to address interstate transport obligations for the 
2008 ozone NAAQS.\10\ On March 27, 2018, we issued a memorandum (March 
2018 memorandum) noting that the same 2023 modeling data released in 
the October 2017 memorandum could also be useful for identifying 
potential downwind air quality problems with respect to the 2015 8-hour 
ozone NAAQS at Step 1 of the 4-step interstate transport framework.\11\ 
The March 2018 memorandum also included the then newly available 
contribution modeling data for 2023 to assist states in evaluating 
their impact on potential downwind air quality problems for the 2015 8-
hour ozone NAAQS under Step 2 of the 4-step interstate transport 
framework.\12\ The EPA subsequently issued two more memoranda in August 
and October 2018, providing additional information to states developing 
interstate transport SIP submissions for the 2015 8-hour ozone NAAQS 
concerning, respectively, potential contribution thresholds that may be 
appropriate to apply in Step 2 of the 4-step interstate transport 
framework, and considerations for identifying downwind areas that may 
have problems maintaining the standard at Step 1 of the 4-step 
interstate transport framework.\13\
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    \8\ See Notice of Availability of the Environmental Protection 
Agency's Preliminary Interstate Ozone Transport Modeling Data for 
the 2015 8-hour Ozone National Ambient Air Quality Standard (NAAQS), 
82 FR 1733 (January 6, 2017).
    \9\ See 82 FR 1733, 1735 (January 6, 2017).
    \10\ See Information on the Interstate Transport State 
Implementation Plan Submissions for the 2008 Ozone National Ambient 
Air Quality Standards under Clean Air Act Section 
110(a)(2)(D)(i)(I), October 27, 2017, available in the docket for 
this action or at https://www.epa.gov/interstate-air-pollution-transport/interstate-air-pollution-transport-memos-and-notices.
    \11\ See Information on the Interstate Transport State 
Implementation Plan Submissions for the 2015 Ozone National Ambient 
Air Quality Standards under Clean Air Act Section 
110(a)(2)(D)(i)(I), March 27, 2018 (``March 2018 memorandum''), 
available in the docket for this action or at https://www.epa.gov/interstate-air-pollution-transport/interstate-air-pollution-transport-memos-and-notices.
    \12\ The March 2018 memorandum, however, provided, ``While the 
information in this memorandum and the associated air quality 
analysis data could be used to inform the development of these SIPs, 
the information is not a final determination regarding states' 
obligations under the good neighbor provision. Any such 
determination would be made through notice-and-comment rulemaking.''
    \13\ See Analysis of Contribution Thresholds for Use in Clean 
Air Act Section 110(a)(2)(D)(i)(I) Interstate Transport State 
Implementation Plan Submissions for the 2015 Ozone National Ambient 
Air Quality Standards, August 31, 2018) (``August 2018 
memorandum''), and Considerations for Identifying Maintenance 
Receptors for Use in Clean Air Act Section 110(a)(2)(D)(i)(I) 
Interstate Transport State Implementation Plan Submissions for the 
2015 Ozone National Ambient Air Quality Standards, October 19, 2018, 
available in the docket for this action or at https://www.epa.gov/airmarkets/memo-and-supplemental-information-regarding-interstate-transport-sips-2015-ozone-naaqs.
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    Since the release of the modeling data shared in the March 2018

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memorandum, the EPA performed updated modeling using a 2016-based 
emissions modeling platform (i.e., 2016v1). This emissions platform was 
developed under the EPA/Multi-Jurisdictional Organization (MJO)/state 
collaborative project.\14\ This collaborative project was a multi-year 
joint effort by the EPA, MJOs, and states to develop a new, more recent 
emissions platform for use by the EPA and states in regulatory modeling 
as an improvement over the dated 2011-based platform that the EPA had 
used to project ozone design values and contribution data provided in 
the 2017 and 2018 memoranda. The EPA used the 2016v1 emissions to 
project ozone design values and contributions for 2023. On October 30, 
2020, in the Notice of Proposed Rulemaking for the Revised CSAPR 
Update, the EPA released and accepted public comment on 2023 modeling 
that used the 2016v1 emissions platform.\15\ Although the Revised CSPAR 
Update addressed transport for the 2008 ozone NAAQS, the projected 
design values and contributions from the 2016v1 platform are also 
useful for identifying downwind ozone problems and linkages with 
respect to the 2015 ozone NAAQS.\16\
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    \14\ The results of this modeling, as well as the underlying 
modeling files, are included in docket EPA-HQ-OAR-2021-0663.
    \15\ See 85 FR 68964, 68981
    \16\ See the Air Quality Modeling Technical Support Document for 
the Final Revised Cross-State Air Pollution Rule Update, included in 
the Headquarters docket ID No. EPA-HQ-OAR-2021-0663.
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    Following the final Revised CSAPR Update, the EPA made further 
updates to the 2016 emissions platform to include mobile emissions from 
the EPA's Motor Vehicle Emission Simulator MOVES3 model \17\ and 
updated emissions projections for electric generating units (EGUs) that 
reflect the emissions reductions from the Revised CSAPR Update, recent 
information on plant closures, and other sector trends. The construct 
of the updated emissions platform, 2016v2 (2016v2 emissions platform), 
is described in the emissions modeling technical support document (TSD) 
for this proposed rulemaking.\18\ The EPA performed air quality 
modeling of the 2016v2 emissions using the most recent public release 
version of the Comprehensive Air-quality Model with extensions (CAMx) 
photochemical modeling, version 7.10.\19\ The EPA now proposes to 
primarily rely on modeling based on the updated and newly available 
2016v2 emissions platform in evaluating these submissions with respect 
to Steps 1 and 2 of the 4-step interstate transport framework and 
generally referenced within this action as 2016v2 modeling for 2023. By 
using the updated modeling results, the EPA is using the most current 
and technically appropriate information for this proposed rulemaking. 
Section III of this document and the Air Quality Modeling TSD for 2015 
8-hour Ozone NAAQS Transport SIP Proposed Actions, included in Docket 
ID No. EPA-HQ-OAR-2021-0663 for this proposal, contain additional 
detail on the EPA's 2016v2 modeling. In this document, the EPA is 
accepting public comment on this updated 2023 modeling, which uses a 
2016v2 emissions platform. Comments on the EPA's air quality modeling 
should be submitted in the Regional docket for this action, Docket ID 
No. EPA-R03-OAR-2021-0873. No comments on any topic are being accepted 
in docket ID No. EPA-HQ-OAR-2021-0663.
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    \17\ Additional details and documentation related to the MOVES3 
model can be found at https://www.epa.gov/moves/latest-version-motor-vehicle-emission-simulator-moves.
    \18\ See Technical Support Document (TSD) Preparation of 
Emissions Inventories for the 2016v2 North American Emissions 
Modeling Platform, included in the Headquarters docket ID No. EPA-
HQ-OAR-2021-0663.
    \19\ Ramboll Environment and Health, January 2021, www.camx.com.
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    States may have chosen to rely on the results of EPA modeling and/
or alternative modeling performed by states or MJOs to evaluate 
downwind air quality problems and contributions as part of their 
submissions. EPA's evaluation of how West Virginia used air quality 
modeling information in their submission is in Section III of this 
document.

D. The EPA's Approach to Evaluating Interstate Transport SIPs for the 
2015 8-Hour Ozone NAAQS

    The EPA proposes to apply a consistent set of policy judgments 
across all states for purposes of evaluating interstate transport 
obligations and the approvability of interstate transport SIP 
submittals for the 2015 8-hour ozone NAAQS. These policy judgments 
reflect consistency with relevant case law and past agency practice as 
reflected in the CSAPR and related rulemakings. Nationwide consistency 
in approach is particularly important in the context of interstate 
ozone transport, which is a regional-scale pollution problem involving 
many smaller contributors. Effective policy solutions to the problem of 
interstate ozone transport going back to the NOX SIP Call 
have necessitated the application of a uniform framework of policy 
judgments in order to ensure an ``efficient and equitable'' approach. 
See EME Homer City Generation, LP v. EPA, 572 U.S. 489, 519 (2014).
    In the March, August, and October 2018 memoranda, the EPA 
recognized that states may be able to establish alternative approaches 
to addressing their interstate transport obligations for the 2015 8-
hour ozone NAAQS that vary from a nationally uniform framework. The EPA 
emphasized in these memoranda, however, that such alternative 
approaches must be technically justified and appropriate in light of 
the facts and circumstances of each particular state's submittal. In 
general, the EPA continues to believe that deviation from a nationally 
consistent approach to ozone transport must be substantially justified 
and have a well-documented technical basis that is consistent with 
relevant case law. Where states submitted SIPs that rely on any such 
potential ``flexibilities'' as may have been identified or suggested in 
the past, the EPA will evaluate whether the state adequately justified 
the technical and legal basis for doing so. The EPA's proposed 
framework with respect to analytic year, definition of nonattainment 
and maintenance receptors, selection of contribution threshold, and 
multifactor control strategy assessment is described in this section. 
The EPA notes that certain concepts included in an attachment to the 
March 2018 memorandum require unique consideration, and these ideas do 
not constitute agency guidance with respect to transport obligations 
for the 2015 ozone NAAQS. Attachment A to the March 2018 memorandum 
identified a ``Preliminary List of Potential Flexibilities'' that could 
potentially inform SIP development.\20\ However, EPA made clear in that 
Attachment that the list of ideas were not suggestions endorsed by the 
Agency but rather ``comments provided in various forums'' on which EPA 
sought ``feedback from interested stakeholders.'' \21\ Further, 
Attachment A stated, ``EPA is not at this time making any determination 
that the ideas discussed below are consistent with the requirements of 
the CAA, nor is the EPA specifically recommending that states use these 
approaches.'' \22\ Attachment A to the March 2018 memorandum, 
therefore, does not constitute agency guidance, but was intended to 
generate further discussion around potential approaches to addressing 
ozone transport among interested stakeholders. To the extent

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states sought to develop or rely on these ideas in support of their SIP 
submittals, the EPA will thoroughly review the technical and legal 
justifications for doing so.
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    \20\ March 2018 memorandum, Attachment A.
    \21\ Id. at A-1.
    \22\ Id.
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    The remainder of this section describes the EPA's proposed 
framework with respect to analytic year, definition of nonattainment 
and maintenance receptors, selection of contribution threshold, and 
multifactor control strategy assessment.
1. Selection of Analytic Year
    In general, the states and the EPA must implement the interstate 
transport provision in a manner ``consistent with the provisions of 
[title I of the CAA.]'' CAA section 110(a)(2)(D)(i). This requires, 
among other things, that these obligations are addressed consistently 
with the timeframes for downwind areas to meet their CAA obligations. 
With respect to ozone NAAQS, under CAA section 181(a), this means 
obligations must be addressed ``as expeditiously as practicable'' and 
no later than the schedule of attainment dates provided in CAA section 
181(a)(1).\23\ Several D.C. Circuit court decisions address the issue 
of the relevant analytic year for the purposes of evaluating ozone 
transport air-quality problems. On September 13, 2019, the D.C. Circuit 
issued a decision in Wisconsin v. EPA, remanding the CSAPR Update to 
the extent that it failed to require upwind states to eliminate their 
significant contribution by the next applicable attainment date by 
which downwind states must come into compliance with the NAAQS, as 
established under CAA section 181(a). 938 F.3d 303 at 313.
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    \23\ For attainment dates for the 2015 8-hour ozone NAAQS, refer 
to CAA section 181(a), 40 CFR 51.1303, and Additional Air Quality 
Designations for the 2015 Ozone National Ambient Air Quality 
Standards, 83 FR 25776 (June 4, 2018, effective August 3, 2018).
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    On May 19, 2020, the D.C. Circuit issued a decision in Maryland v. 
EPA that cited the Wisconsin decision in holding that the EPA must 
assess the impact of interstate transport on air quality at the next 
downwind attainment date, including Marginal area attainment dates, in 
evaluating the basis for the EPA's denial of a petition under CAA 
section 126(b). Maryland v. EPA, 958 F.3d 1185, 1203-04 (D.C. Cir. 
2020). The court noted that ``section 126(b) incorporates the Good 
Neighbor Provision,'' and, therefore, ``EPA must find a violation [of 
section 126] if an upwind source will significantly contribute to 
downwind nonattainment at the next downwind attainment deadline. 
Therefore, the agency must evaluate downwind air quality at that 
deadline, not at some later date.'' Id. at 1204 (emphasis added). The 
EPA interprets the court's holding in Maryland as requiring the Agency, 
under the good neighbor provision, to assess downwind air quality as 
expeditiously as practicable and no later than the next applicable 
attainment date,\24\ which is now the Moderate area attainment date 
under CAA section 181 for ozone nonattainment. The Moderate area 
attainment date for the 2015 8-hour ozone NAAQS is August 3, 2024.\25\ 
The EPA believes that 2023 is now the appropriate year for analysis of 
interstate transport obligations for the 2015 8-hour ozone NAAQS 
because the 2023 ozone season is the last relevant ozone season during 
which achieved emissions reductions in linked upwind states could 
assist downwind states with meeting the August 3, 2024 Moderate area 
attainment date for the 2015 8-hour ozone NAAQS.
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    \24\ We note that the court in Maryland did not have occasion to 
evaluate circumstances in which the EPA may determine that an upwind 
linkage to a downwind air quality problem exists at steps 1 and 2 of 
the interstate transport framework by a particular attainment date, 
but for reasons of impossibility or profound uncertainty the Agency 
is unable to mandate upwind pollution controls by that date. See 
Wisconsin, 938 F.3d at 320. The D.C. Circuit noted in Wisconsin that 
upon a sufficient showing, these circumstances may warrant 
flexibility in effectuating the purpose of the interstate transport 
provision.
    \25\ See CAA section 181(a); 40 CFR 51.1303; Additional Air 
Quality Designations for the 2015 Ozone National Ambient Air Quality 
Standards, 83 FR 25776 (June 4, 2018, effective August 3, 2018).
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    The EPA recognizes that the attainment date for nonattainment areas 
classified as Marginal for the 2015 8-hour ozone NAAQS was August 3, 
2021. Under the Maryland holding, any necessary emissions reductions to 
satisfy interstate transport obligations should have been implemented 
by no later than this date. At the time of the statutory deadline to 
submit interstate transport SIPs (October 1, 2018), many states relied 
upon the EPA modeling of the year 2023, and no state provided an 
alternative analysis using a 2021 analytic year (or the prior 2020 
ozone season). However, the EPA must act on SIP submittals using the 
information available at the time it takes such action. In this 
circumstance, the EPA does not believe it would be appropriate to 
evaluate states' obligations under CAA section 110(a)(2)(D)(i)(I) as of 
an attainment date that is wholly in the past, because the Agency 
interprets the interstate transport provision as forward looking. See 
86 FR at 23074(April 30, 2021); see also Wisconsin, 938 F.3d at 322. 
Consequently, in this proposal the EPA will use the analytical year of 
2023 to evaluate each state's CAA section 110(a)(2)(D)(i)(I) SIP 
submission with respect to the 2015 8-hour ozone NAAQS.
2. Step 1 of the 4-Step Interstate Transport Framework
    In Step 1, the EPA identifies monitoring sites that are projected 
to have problems attaining and/or maintaining the NAAQS in the 2023 
analytic year. Where the EPA's analysis shows that a site does not fall 
under the definition of a nonattainment or maintenance receptor, that 
site is excluded from further analysis under the EPA's 4-step 
interstate transport framework. For sites that are identified as a 
nonattainment or maintenance receptor in 2023, we proceed to the next 
step of our 4-step interstate transport framework by identifying the 
upwind state's contribution to those receptors.
    The EPA's approach to identifying ozone nonattainment and 
maintenance receptors in this action is consistent with the approach 
used in previous transport rulemakings. The EPA's approach gives 
independent consideration to both the ``contribute significantly to 
nonattainment'' and the ``interfere with maintenance'' prongs of CAA 
section 110(a)(2)(D)(i)(I), consistent with the D.C. Circuit's 
direction in North Carolina v. EPA.\26\
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    \26\ See North Carolina v. EPA, 531 F.3d 896, 910-11 (D.C. Cir. 
2008) (holding that the EPA must give ``independent significance'' 
to each prong of CAA section 110(a)(2)(D)(i)(I)).
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    For the purpose of this proposal, the EPA identifies nonattainment 
receptors as those monitoring sites that are projected to have average 
design values that exceed the NAAQS and that are also measuring 
nonattainment based on the most recent monitored design values. This 
approach is consistent with prior transport rulemakings, such as the 
CSAPR Update, where the EPA defined nonattainment receptors as those 
areas that both currently measure nonattainment and that the EPA 
projects will be in nonattainment in the future analytic year (i.e., 
2023).\27\
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    \27\ See 81 FR 74504 (October 26, 2016). This same concept, 
relying on both current monitoring data and modeling to define 
nonattainment receptor, was also applied in CAIR. See 70 FR 25241 
(January 14, 2005); see also North Carolina, 531 F.3d at 913-14 
(affirming as reasonable EPA's approach to defining nonattainment in 
CAIR).
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    In addition, in this proposal, the EPA identifies a receptor to be 
a ``maintenance'' receptor for purposes of defining interference with 
maintenance, consistent with the method used in the CSAPR and upheld by 
the D.C. Circuit in EME Homer City Generation, L.P. v. EPA, 795 F.3d 
118, 136 (D.C. Cir.

[[Page 9521]]

2015).\28\ Specifically, the EPA identified maintenance receptors as 
those receptors that would have difficulty maintaining the relevant 
NAAQS in a scenario that takes into account historical variability in 
air quality at that receptor. The variability in air quality was 
determined by evaluating the ``maximum'' future design value at each 
receptor based on a projection of the maximum measured design value 
over the relevant period. The EPA interprets the projected maximum 
future design value to be a potential future air quality outcome 
consistent with the meteorology that yielded maximum measured 
concentrations in the ambient data set analyzed for that receptor 
(i.e., ozone conducive meteorology). The EPA also recognizes that 
previously experienced meteorological conditions (e.g., dominant wind 
direction, temperatures, air mass patterns) promoting ozone formation 
that led to maximum concentrations in the measured data may reoccur in 
the future. The maximum design value gives a reasonable projection of 
future air quality at the receptor under a scenario in which such 
conditions do, in fact, reoccur. The projected maximum design value is 
used to identify upwind emissions that, under those circumstances, 
could interfere with the downwind area's ability to maintain the NAAQS.
---------------------------------------------------------------------------

    \28\ See 76 FR 48208 (August 8, 2011). CSAPR Update and Revised 
CSAPR Update also used this approach. See 81 FR 74504 (October 26, 
2016) and 86 FR 23054 (April 30, 2021).
---------------------------------------------------------------------------

    Recognizing that nonattainment receptors are also, by definition, 
maintenance receptors, the EPA often uses the term ``maintenance-only'' 
to refer to those receptors that are not nonattainment receptors. 
Consistent with the concepts for maintenance receptors, as described 
above, the EPA identifies ``maintenance-only'' receptors as those 
monitoring sites that have projected average design values above the 
level of the applicable NAAQS, but that are not currently measuring 
nonattainment based on the most recent official design values. In 
addition, those monitoring sites with projected average design values 
below the NAAQS, but with projected maximum design values above the 
NAAQS are also identified as ``maintenance only'' receptors, even if 
they are currently measuring nonattainment based on the most recent 
official design values.
3. Step 2 of the 4-Step Interstate Transport Framework
    In Step 2, the EPA quantifies the contribution of each upwind state 
to each receptor in the 2023 analytic year. The contribution metric 
used in Step 2 is defined as the average impact from each state to each 
receptor on the days with the highest ozone concentrations at the 
receptor based on the 2023 modeling. If a state's contribution value 
does not equal or exceed the threshold of 1 percent of the NAAQS (i.e., 
0.70 parts per billion (ppb) for the 2015 8-hour ozone NAAQS), the 
upwind state is not ``linked'' to a downwind air quality problem, and 
the EPA, therefore, concludes that the state does not significantly 
contribute to nonattainment or interfere with maintenance of the NAAQS 
in the downwind states. However, if a state's contribution equals or 
exceeds the 1 percent threshold, the state's emissions are further 
evaluated in Step 3, considering both air quality and cost as part of a 
multi-factor analysis, to determine what, if any, emissions might be 
deemed ``significant'' and, thus, must be eliminated under CAA section 
110(a)(2)(D)(i)(I). The EPA is proposing to rely in the first instance 
on the 1 percent threshold (i.e., 0.70 ppb) for the purpose of 
evaluating a state's contribution to nonattainment or maintenance of 
the 2015 8-hour ozone NAAQS at downwind receptors. This is consistent 
with the Step 2 approach that EPA applied in CSAPR for the 1997 ozone 
NAAQS, which has subsequently been applied in the CSAPR Update when 
evaluating interstate transport obligations for the 2008 ozone NAAQS. 
The EPA continues to find 1 percent to be an appropriate threshold. For 
ozone, as the EPA found in the Clean Air Interstate Rule (CAIR), CSAPR, 
and CSAPR Update, a portion of the nonattainment problems from 
anthropogenic sources in the U.S. result from the combined impact of 
relatively small contributions from many upwind states, along with 
contributions from in-state sources and, in some cases, substantially 
larger contributions from a subset of particular upwind states. The 
EPA's analysis shows that much of the ozone transport problem being 
analyzed in this proposed rulemaking is still the result of the 
collective impacts of contributions from many upwind states. Therefore, 
application of a consistent contribution threshold is necessary to 
identify those upwind states that should have responsibility for 
addressing their contribution to the downwind nonattainment and 
maintenance problems to which they collectively contribute. Continuing 
to use 1 percent of the NAAQS as the screening metric to evaluate 
collective contribution from many upwind states also allows the EPA 
(and states) to apply a consistent framework to evaluate interstate 
emissions transport under the interstate transport provision from one 
NAAQS to the next. See 81 FR at 74518 (October 26, 2016). See also 86 
FR at 23085 (April 30, 2021) (reviewing and explaining rationale from 
CSAPR, 76 FR at 48237-38 (August 8, 2011), for selection of 1 percent 
threshold).
    The EPA's August 2018 memorandum recognized that in certain 
circumstances, a state may be able to establish that an alternative 
contribution threshold of 1 ppb is justifiable. Where a state relies on 
this alternative threshold, and where that state determined that it was 
not linked at Step 2 using the alternative threshold, the EPA will 
evaluate whether the state provided a technically sound assessment of 
the appropriateness of using this alternative threshold based on the 
facts and circumstances underlying its application in the particular 
SIP submission.
4. Step 3 of the 4-Step Interstate Transport Framework
    Consistent with the EPA's longstanding approach to eliminating 
significant contribution or interference with maintenance, at Step 3, 
states linked at Steps 1 and 2 are generally expected to prepare a 
multifactor assessment of potential emissions controls. The EPA's 
analysis at Step 3 in prior Federal actions addressing interstate 
transport requirements has primarily focused on an evaluation of cost-
effectiveness of potential emissions controls (on a marginal cost-per-
ton basis), the total emissions reductions that may be achieved by 
requiring such controls (if applied across all linked upwind states), 
and an evaluation of the air quality impacts such emissions reductions 
would have on the downwind receptors to which a state is linked; other 
factors may potentially be relevant if adequately supported. In 
general, where the EPA's or alternative air quality and contribution 
modeling establishes that a state is linked at Steps 1 and 2, it will 
be insufficient at Step 3 for a state merely to point to its existing 
rules requiring control measures as a basis for approval. In general, 
the emissions-reducing effects of all existing emissions control 
requirements are already reflected in the air quality results of the 
modeling for Steps 1 and 2. If the state is shown to still be linked to 
one or more downwind receptor(s), states must provide a well-

[[Page 9522]]

documented evaluation determining whether their emissions constitute 
significant contribution or interference with maintenance by evaluating 
additional available control opportunities by preparing a multifactor 
assessment. While the EPA has not prescribed a particular method for 
this assessment, the EPA expects states at a minimum to present a 
sufficient technical evaluation. This would typically include 
information on emissions sources, applicable control technologies, 
emissions reductions and costs, cost effectiveness, and downwind air 
quality impacts of the estimated reductions, before concluding that no 
additional emissions controls should be required.\29\
---------------------------------------------------------------------------

    \29\ As examples of general approaches for how such an analysis 
could be conducted for their sources, states could look to the CSAPR 
Update, 81 FR 74504, 74539-51; CSAPR, 76 FR 48208, 48246-63 (August 
8, 2011); CAIR, 70 FR 25162, 25195-229 (May 12, 2005).; or the 
NOX SIP Call, 63 FR 57356, 57399-405 (October 27, 1998). 
See also Revised CSAPR Update, 86 FR 23054, 23086-23116 (April 30, 
2021). Consistently across these rulemakings, the EPA has developed 
emissions inventories, analyzed different levels of control 
stringency at different cost thresholds, and assessed downwind air 
quality improvements.
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5. Step 4 of the 4-Step Interstate Transport Framework
    At Step 4, states (or the EPA) develop permanent and federally 
enforceable control strategies to achieve the emissions reductions 
determined to be necessary at Step 3 to eliminate significant 
contribution to nonattainment or interference with maintenance of the 
NAAQS. For a state linked at Steps 1 and 2 to rely on an emissions 
control measure at Step 3 to address its interstate transport 
obligations, that measure must be included in the state's SIP so that 
it is permanent and federally enforceable. See CAA section 110(a)(2)(D) 
(``Each such [SIP] shall . . . contain adequate provisions . . .''). 
See also CAA section 110(a)(2)(A); Committee for a Better Arvin v. U.S. 
E.P.A., 786 F.3d 1169, 1175-76 (9th Cir. 2015) (holding that measures 
relied on by state to meet CAA requirements must be included in the 
SIP).

II. West Virginia's SIP Submission Addressing Interstate Transport of 
Air Pollution for the 2015 8-Hour Ozone NAAQS

    On September 14, 2018, the West Virginia Department of 
Environmental Protection (WVDEP), on behalf of the State of West 
Virginia, made a SIP submission to address most of the 2015 8-hour 
ozone NAAQS i-SIP requirements under CAA section 110(a)(2), except for 
the CAA section 110(a)(2)(D)(i)(I) (the ``Good Neighbor'' or 
``interstate transport'') requirements, which West Virginia proposed to 
address in a separate SIP submittal. The EPA published a final approval 
of this SIP submission on March 17, 2020. 85 FR 15071. On February 4, 
2019, WVDEP submitted a separate, supplemental SIP revision addressing 
only the CAA Section 110(a)(2)(D)(i)(I) interstate transport 
requirements for the 2015 8-hour ozone NAAQS (the 2019 SIP).\30\ West 
Virginia's 2019 SIP submittal evaluated different modeling options, 
provided an analysis of ozone monitoring data and emission trends, and 
argued that the State has already implemented adequate measures to 
address pollutant transport that may significantly contribute to 
downwind states' ozone maintenance and nonattainment problems, before 
concluding that West Virginia has satisfied its section 
110(a)(2)(D)(i)(I) Good Neighbor obligations for the 2015 8-hour ozone 
NAAQS.
---------------------------------------------------------------------------

    \30\ See the 2019 SIP submittal included in docket EPA-R03-OAR-
2021-0873.
---------------------------------------------------------------------------

    WVDEP requested that the EPA ``conditionally'' approve the 2019 SIP 
submittal, because at the time of submission, WVDEP had a proposed 
rulemaking pending before the West Virginia Legislature for approval 
during the 2019 legislative session. The proposed rulemaking, entitled 
``45CSR43--Cross-State Air Pollution Rule to Control Annual Nitrogen 
Oxide Emissions, Annual Sulfur Dioxide Emissions and Ozone Season 
Nitrogen Oxide Emissions,'' would incorporate by reference into the 
West Virginia regulations the following emissions trading programs set 
forth in the CSAPR and CSAPR Update regulations: 40 CFR part 97, 
subpart AAAAA (CSAPR NOX Annual Trading Program), subpart 
CCCCC (CSAPR SO2 Group 1 Trading Program), and subpart EEEEE 
(CSAPR NOX Ozone Season Group 2 Trading Program). Following 
the submission of this 2019 SIP revision, the West Virginia Legislature 
approved the state regulation incorporating by reference these 
subparts, and WVDEP submitted a SIP revision requesting that the EPA 
approve this regulation into the West Virginia SIP on June 5, 2019. The 
EPA proposed approval of this SIP revision on August 16, 2019. 84 FR 
41944.\31\ WVDEP claimed that following the EPA final approval of the 
SIP revision incorporating these programs, the West Virginia SIP would 
contain all the measures necessary to ensure that it met the good 
neighbor obligations of the CAA section 110(a)(2)(D)(i)(I) for the 2015 
8-hour ozone NAAQS. The EPA has not taken final action on that SIP 
revision.\32\
---------------------------------------------------------------------------

    \31\ Docket No. EPA-R03-OAR-2019-0349.
    \32\ The D.C. Circuit court's decision in Wisconsin v. EPA, 938 
F.3d 303 (September 13, 2019) remanding the CSAPR Update rule to EPA 
for further consideration prevented final approval of West 
Virginia's SIP submission.
---------------------------------------------------------------------------

    WVDEP's submittal to address interstate transport for the 2015 8-
hour ozone NAAQS roughly followed the 4-step interstate transport 
framework, as briefly described here. At Step 1, WVDEP discussed and 
compared the EPA's transport modeling provided in the March 2018 
memorandum against transport modeling provided by Alpine and LADCO and 
decided that the Alpine modeling was the ``most appropriate, robust 
modeling available to identify the nonattainment and maintenance 
receptors to which West Virginia significantly contributes.'' Alpine 
released air quality modeling in June 2018, which used a 12-km grid 
(supplemented with two 4-km nested grids) based on the EPA's 2023en 
modeling platform and preliminary source contribution assessment. In 
addition to air quality modeling, the Alpine TSD \33\ included a 
discussion of ``Selected SIP Revision Approaches'' based on information 
on the ``flexibilities'' listed in an appendix to the EPA's March 2018 
Memorandum. Alpine's air quality modeling incorporated meteorological 
data from the WRF model along with emissions data developed using 
SMOKE, MOVES2014, and BEIS version 3.61. Alpine used CAMx, and the 
OSAT/APCA tool to project ozone concentrations at downwind receptors. 
The modeling used 2023 as the projection year based on the EPA's 
guidance in the 2017 Memorandum stating that 2023 was the appropriate 
year to use. As shown in Table 1 of this document, Alpine modeling 
projected that in the Mid-Atlantic region, one receptor would have 
nonattainment issues and nine receptors would have maintenance problems 
in 2023 with respect to the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    \33\ See Appendix E of the WVDEP submittal. ``Good Neighbor'' 
Modeling Technical Support Document for 8-Hour Ozone State 
Implementation Plans.'' Alpine Geophysics, June 2018.

[[Page 9523]]



                Table 1--Receptors Identified by West Virginia Using Alpine's June 2018 Modeling
----------------------------------------------------------------------------------------------------------------
                                                                   2023 Average    2023  Maximum     2014-2016
         Receptor ID               Location       Nonattainment/   design value    design value    Actual design
                                                   maintenance         (ppb)           (ppb)       value  (ppb)
----------------------------------------------------------------------------------------------------------------
240251001....................  Harford, MD.....  Nonattainment..            71.1            73.5              73
551170006....................  Sheboygan, WI...  Nonattainment..            71.7            74.0              79
90010017.....................  Fairfield, CT...  Maintenance....            69.2            71.5              80
90013007.....................  Farifield, CT...  Maintenance....            69.7            73.6              81
90019003.....................  Farifield, CT...  Maintenance....            69.9            72.7              83
90099002.....................  New Haven, CT...  Maintenance....            70.3            73.0              76
90110124.....................  New London, CT..  Maintenance....            68.2            71.3              72
260050003....................  Allegan, MI.....  Maintenance....            70.3            73.1              75
340150002....................  Gloucester, NJ..  Maintenance....            68.8            71.0              74
360850067....................  Richmond, NY....  Maintenance....            69.6            71.0              76
361030002....................  Suffolk, NY.....  Maintenance....            70.7            72.1              72
421010024....................  Philadelphia, PA  Maintenance....            68.0            71.0              77
----------------------------------------------------------------------------------------------------------------

    At Step 2 of the analysis, WVDEP noted that the Alpine modeling 
projected that West Virginia would be ``linked'' to the only downwind 
2023 nonattainment receptor and three maintenance receptors in the Mid-
Atlantic 4-km region. The contribution results of the Alpine modeling 
are shown in Table 2 of this document. WVDEP noted that the Alpine 
modeling projected that West Virginia's largest identified contribution 
to downwind 8-hour ozone nonattainment and maintenance receptors was 
2.52 ppb and 1.63 ppb, respectively.

             Table 2--West Virginia's Contribution to Receptors Based on Alpine's June 2018 Modeling
----------------------------------------------------------------------------------------------------------------
                                                                   2023 Average    2023  Maximum   West Virginia
         Receptor ID               Location       Nonattainment/   design value    design value    contribution
                                                   maintenance         (ppb)           (ppb)           (ppb)
----------------------------------------------------------------------------------------------------------------
240251001....................  Harford County,   Nonattainment..            71.1            73.5            2.52
                                MD.
340150002....................  Gloucester        Maintenance....            68.8            71.0            1.63
                                County, NJ.
360850067....................  Richmond County,  Maintenance....            69.6            71.0            0.71
                                NY.
421010024....................  Philadelphia      Maintenance....            68.0            71.0            1.21
                                County, PA.
----------------------------------------------------------------------------------------------------------------

    WVDEP identified specific receptors for further analysis, based 
upon the Alpine modeling that indicated that emissions from the State 
would be ``linked'' to the downwind ozone nonattainment receptor at 
Harford, Maryland, and to three maintenance receptors at Gloucester, 
New Jersey; Richmond, New York; and Philadelphia, Pennsylvania. 
Therefore, WVDEP stated that further review and analysis relevant to 
those areas was warranted. With respect to these specific monitors, 
WVDEP also presented further analysis of the air pollution problems at 
these four locations in Section 4 of the SIP submittal, entitled 
``Flexibilities.''
    At Step 3, WVDEP noted that it is necessary to identify the 
emissions reductions necessary (if any), considering cost and air 
quality factors, to prevent the identified upwind state from 
contributing significantly to downwind air quality problems. To do 
this, WVDEP reviewed NOX emissions data from EPA's 2008, 
2011, 2014 and 2017 NEI Air Pollution Emissions Trends Data website, to 
evaluate emissions' trends data for all Tier 1 Categories from 1990 
through 2017.\34\ This review determined that six categories of Tier 1 
sources accounted for approximately 95% of the State's NOX 
emissions in 2017, and thus WVDEP focused its evaluation of potential 
controls and the cost-effectiveness of those controls on these six 
categories of sources in West Virginia.
---------------------------------------------------------------------------

    \34\ This website provides current emissions trends data for all 
Tier 1 Categories from 1990 through 2017. See also https://www.epa.gov/air-emissions-inventories/what-sources-make-tier-1-categories-used-emissions-trends.
---------------------------------------------------------------------------

    For two of these categories--highway vehicles and off-highway 
vehicles--WVDEP determined that these emission sources are regulated by 
the Federal government, and therefore declined to conduct any further 
analysis of emissions reduction opportunities. For the other four 
categories--fuel combustion electric utilities, fuel combustion 
industrial, fuel combustion other, and petroleum and related 
industries--WVDEP grouped these into two categories for analysis: EGUs 
and non-EGUs. For the EGU category, WVDEP identified the shutdown of 
six EGUs since 2011 and the amount of emissions that these sources 
emitted prior to shutdown. For those EGUs still operating, WVDEP relied 
upon the EPA's analysis in the proposed CSAPR Update for its finding 
that ``because all identified highly cost-effective emission reductions 
have already been implemented with respect to EGUs, WV finds that no 
additional highly cost-effective reductions are available for EGUs for 
the 2015 ozone NAAQS.''
    For the non-EGU categories, WVDEP relied upon a technical support 
document (TSD) developed by the EPA analyzing available controls and 
the costs for non-EGU sources for the CSAPR Update. This TSD identified 
nine non-EGU sources in West Virginia emitting more than 100 tons per 
year of NOX, and 21 West Virginia sources emitting between 
25 and 100 tons per year of NOX. WVDEP then listed those 
sources in these two groupings which have shut down, or will shut down 
in the near future, and the reduction in NOX emissions from 
the 2011 base year attributable to these past and future shutdowns and 
various other information before determining that ``[t]he shutdown of 
the identified 10 sources; the required shutdown of the

[[Page 9524]]

additional five sources; and the current level of control on the 
remaining 20 sources, in conjunction with the implementation of the 
Control Measures programs listed in Section 6, represent the 
implementation of reasonable control measures in West Virginia.''
    For the petroleum category, WVDEP separately opined that its 
approved permitting programs would prevent new or modified sources from 
causing or contributing to a violation of the NAAQS and included a 
discussion of these programs in section 6.1 of the SIP submittal.
    At Step 4 of its analysis, WVDEP identified the control measures it 
has already implemented or is subject to that ``reasonably'' reduce 
emissions from relevant sources located in the State. Among the 
measures identified by WVDEP in its SIP submittal are permitting 
programs, stationary source control measures, and mobile source control 
measures. WVDEP also determined that the adoption of a regional trading 
program to replace the CSAPR Update FIP under 45CSR43 was sufficient to 
address the State's significant contribution to the downwind receptors. 
Upon approval of West Virginia's 45CSR43 into the SIP, WVDEP states 
that its SIP will contain the necessary measures to reduce the State's 
impact on the identified downwind receptors for purposes of the 2015 
ozone NAAQS.
    Under the permitting programs, WVDEP referenced the State's NSR 
permit program, which includes revision of applications, determination 
of permit applicability and issuance of permits for both minor \35\ and 
major \36\ sources. Under the minor source NSR program, the 
construction or modification of a source with the potential to emit six 
or more pounds per hour (lbs/hr), or greater than 144 pounds per 
calendar day, of a regulated pollutant, including ozone precursors, 
requires that the source obtain a permit under the state rule 45CSR13. 
WVDEP stated that ``45CSR13 is the mechanism under which NSPS are 
applied to a given minor source,'' and reductions from sources subject 
to NSPS are assumed to be equivalent to reasonably available control 
technology/reasonably available control measures (RACT/RACM).
---------------------------------------------------------------------------

    \35\ Permitting requirements for minor sources are codified at 
45CSR13--Permits for Construction, Modification, Relocation and 
Operation of Stationary Sources of Air Pollutants, Notification 
Requirements, Administrative Updates, Temporary Permits, General 
Permits, Permission to Commence Construction, and Procedures for 
Evaluation.
    \36\ Permitting requirements for major sources are codified at 
45CSR14--Permits for the Construction and Major Modification of 
Major Stationary Sources of Air Pollution for the Prevention of 
Significant Deterioration, and 45CSR19--Permits for Construction and 
Major Modification of Major Stationary Sources Which Cause or 
Contribute to Nonattainment Areas and 45CSR30--Requirements for 
Operating Permits.
---------------------------------------------------------------------------

    For major stationary sources, WVDEP referenced two additional 
permitting programs: One that satisfies the prevention of significant 
deterioration (PSD) requirements under Part C of Title 1 of the CAA, 
and another that satisfies the nonattainment area NSR (NNSR) 
requirements under Part D of the CAA. These are codified at 45CSR14 
\37\ and 45CSR19,\38\ respectively. WVDEP asserts that the PSD 
regulations at 45CSR14 regulate future growth and thus provide for 
continued maintenance of the 2015 8-hour ozone NAAQS. WVDEP also notes 
that, pursuant to CAA section 165(a)(3), WVDEP is authorized to 
implement the existing PSD permit program to ensure that construction 
and modification of a major source will not cause or contribute to 
violations of the NAAQS.\39\ The State explained that the NNSR 
regulations at 45CSR19 cover new major sources and major modifications, 
not subject to PSD, in nonattainment areas. The State explained that 
this regulation contains a significance level for ozone of 40 tons per 
year of VOC or NOX. WVDEP specified in its SIP submittal 
that there are no areas designated as nonattainment for the 2008 or 
2015 ozone NAAQS in West Virginia.
---------------------------------------------------------------------------

    \37\ Permits for the Construction and Major Modification of 
Major Stationary Sources of Air Pollution for the Prevention of 
Significant Deterioration.
    \38\ Permits for Construction and Major Modification of Major 
Stationary Sources Which Cause or Contribute to Nonattainment Areas.
    \39\ See 45CSR 14-9.1 and 40 CFR 51.166(k).
---------------------------------------------------------------------------

    For stationary sources, WVDEP's submittal also included a list of 
other federally established control measures including: (i) New source 
performance standards (40 CFR part 60); (ii) the Acid Rain Program; 
(iii) the NOX SIP call; (iv) the CAIR; (v) CSAPR; (vi) the 
CSAPR Update; (vii) solid waste combustion rules (40 CFR part 60); and 
(viii) the maximum achievable control technology (MACT) program (i.e., 
the NESHAPS at 40 CFR part 63).
    In addition, WVDEP included a list of control measures for mobile 
sources that EPA has established. These control measures include: (i) 
The 2007 heavy-duty highway rule in 40 CFR part 86, subpart P; (ii) 
Tier 2 vehicle and gasoline sulfur program at 40 CFR part 80, subpart 
H, 40 CFR part 85 and 40 CFR part 86; (iii) Tier 3 motor vehicle 
emission and fuel standards codified under 40 CFR parts 79, 80, 85, 86, 
600, 1036, 1037, 1039, 1042, 1048, 1054, 1065, and 1066; (iv) Tier 4 
vehicle standards; and (v) the nonroad diesel emissions program at 40 
CFR part 89.
    In conclusion, following a review of the emission reductions 
created by shutdowns, and various existing emission control 
requirements, WVDEP states that ``upon incorporation of 45CSR43 into 
the SIP, no additional highly cost-effective reductions are available 
for the 2015 8-hour ozone NAAQS.''

III. EPA Evaluation

    The EPA is proposing to find that WVDEP's February 4, 2019 SIP 
submission does not meet the State's obligations with respect to 
prohibiting emissions that contribute significantly to nonattainment or 
interfere with maintenance of the 2015 8-hour ozone NAAQS in any other 
state. The proposed disapproval is based on both newer, updated 
modeling performed by the EPA that was not available when WVDEP 
submitted its SIP submission to address the requirements of section 
110(a)(2)(D)(i)(I) for the 2015 ozone NAAQS, and the EPA's evaluation 
of WVDEP's SIP submission using the 4-step interstate transport 
framework.

A. West Virginia

1. Evaluation of Information Provided by West Virginia Regarding Steps 
1 and 2
    As explained in Section II of this document, at Step 1 of the 4-
Step interstate transport framework, WVDEP used the Alpine modeling 
released in June 2018 to identify any areas where that modeling would 
project nonattainment or maintenance problems in 2023. Although 
Alpine's June 2018 modeling TSD describes several potential concepts 
identified by outside parties and listed in an appendix to the EPA's 
March 2018 Memorandum, it does not appear that WVDEP relied on those 
so-called ``flexibilities.'' \40\ The nonattainment and maintenance 
receptors identified in Alpine's modeling under Step 1 are listed in 
Table 1 in Section II of this document. Based on the results of the 
Alpine modeling alone, WVDEP acknowledged

[[Page 9525]]

in its SIP submission that it should proceed to Step 2 of the analysis.
---------------------------------------------------------------------------

    \40\ The ``flexibilities'' identified in the Alpine modeling 
TSD, but not used by West Virginia, include removing Canadian and 
Mexican contributions from modeling results, using an alternate 
significant contribution threshold in Step 2 of EPA's four-step 
transport interstate framework, using relative significant impact 
amongst those states similarly contributing to a downwind receptor 
under Step 3 of EPA's four-step transport interstate framework, and 
using alternative timeframes to address the ``interference with 
maintenance'' prong of the good neighbor provision.
---------------------------------------------------------------------------

    At Step 2 of its analysis, WVDEP again relied on Alpine's June 2018 
modeling results and highlighted any receptors to which emissions from 
the State contributed more than 1 percent of the NAAQS (i.e., >0.70 
ppb). Table 2 in Section II of this document identifies receptors from 
Alpine's June 2018 modeling that are projected to receive contribution 
levels from emissions in West Virginia above the 1 percent threshold. 
According to Alpine's June 2018 modeling projections, emissions from 
West Virginia would significantly contribute to the Harford, MD 
nonattainment receptor, with a 2.52 ppm contribution, and to the 
Gloucester, NJ, Richmond, NY, and Philadelphia, PA maintenance 
receptors with contributions of 1.63, 0.71, and 1.21 ppb, respectively.
    WVDEP concluded in its own analysis that it was linked using the 1 
percent of the NAAQS threshold and acknowledged that ``it is [then] 
necessary to identify the emissions reductions (if any), considering 
cost and air quality factors, to prevent West Virginia from 
contributing to downwind air quality problems,'' \41\ which is Step 3 
of the 4-step interstate transport framework.
---------------------------------------------------------------------------

    \41\ See the February 4, 2019 SIP submittal included in docket 
EPA-R03-OAR-2021-0873.
---------------------------------------------------------------------------

    Although WVDEP relied on alternative modeling instead of the EPA's 
modeling included in the March 2018 memorandum, WVDEP acknowledged in 
its SIP submission that it is linked to downwind receptors and is 
projected to contribute above the 1 percent threshold to certain 
nonattainment and/or maintenance receptors in 2023. Because the 
alternative modeling relied on by the state also demonstrates that a 
linkage exists between the state and downwind receptors at Step 2, the 
EPA need not conduct a comparative assessment of the alternative 
modeling. The State's analysis corroborates the conclusion in the EPA's 
most recent modeling.
2. Results of the EPA's Step 1 and Step 2 Modeling and Findings for 
West Virginia
    As described in Section I of this document, the EPA performed air 
quality modeling using the 2016v2 emissions platform to project design 
values and contributions for 2023. These data were examined to 
determine if West Virginia contributes at or above the threshold of 1 
percent of the 2015 8-hour ozone NAAQS (i.e., 0.70 ppb) to any downwind 
nonattainment or maintenance receptor. As shown in Table 1 of this 
document, the data \42\ indicate that in 2023, emissions from West 
Virginia contribute greater than 1 percent of the NAAQS to 
nonattainment or maintenance-only receptors in Fairfield County-
Westport, Fairfield County-Stratford, and New Haven County in 
Connecticut, as well as Bucks County, Pennsylvania.\43\
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    \42\ Design values and contributions at individual monitoring 
sites nationwide are provide in the file: 
2016v2_DVs_state_contributions.xlsx which is included in docket ID 
No. EPA-HQ-OAR-2021-0663.
    \43\ These modeling results are consistent with the results of a 
prior round of 2023 modeling using the 2016v1 emissions platform 
which became available to the public in the fall of 2020 in the 
Revised CSAPR Update, as noted in Section I of this document. That 
modeling showed that West Virginia had a maximum contribution 
greater than 0.70 ppb to at least one nonattainment or maintenance-
only receptor in 2023. These modeling results are included in the 
file ``Ozone Design Values And Contributions Revised CSAPR 
Update.xlsx'' in docket EPA-HQ-OAR-2021-0663.

                   Table 3--West Virginia's Linkage Results Based on EPA 2016v2-Based Modeling
----------------------------------------------------------------------------------------------------------------
                                                                   2023 Average    2023  Maximum   West Virginia
         Receptor ID               Location       Nonattainment/   design value    design value    contribution
                                                   maintenance         (ppb)           (ppb)           (ppb)
----------------------------------------------------------------------------------------------------------------
90099002.....................  New Haven, CT...  Nonattainment..            71.8            73.9            1.45
420170012....................  Bucks, PA.......  Maintenance....            70.7            72.2            1.44
90019003.....................  Fairfield-        Nonattainment..            76.1            76.4            1.34
                                Westport, CT.
90013007.....................  Fairfield-        Nonattainment..            74.2            75.1            1.30
                                Stratford, CT.
----------------------------------------------------------------------------------------------------------------

    We recognize that the results of EPA (2011 and 2016 base year) and 
Alpine (2011 base year) modeling indicated different receptors and 
linkages at Steps 1 and 2 of the framework. These differing results 
regarding receptors and linkages can be affected by the varying 
meteorology from year to year, but this does not indicate that the 
modeling or the EPA or the state's methodology for identifying 
receptors or linkages is inherently unreliable. Rather, these three 
separate modeling runs all indicated: (i) That there would be receptors 
in areas that would struggle with nonattainment or maintenance in the 
future, and (ii) that West Virginia was linked to some set of these 
receptors, even if the receptors and linkages differed from one another 
in their specifics (e.g., a different set of receptors were identified 
to have nonattainment or maintenance problems, or West Virginia was 
linked to different receptors in one modeling run versus another). The 
EPA thinks this common result indicates that West Virginia's emissions 
have been substantial enough to generate linkages at Steps 1 and 2 to 
some set of downwind receptors, under varying assumptions and 
meteorological conditions, even if the precise set of linkages changed 
between modeling runs. Under these circumstances, we think it is 
appropriate to proceed to a Step 3 analysis to determine what portion 
of West Virginia's emissions should be deemed ``significant.'' In doing 
so, the EPA does not necessarily agree with the methods and assumptions 
contained in the Alpine modeling relied on by WVDEP in this action, nor 
that we consider our own earlier modeling to be of equal reliability 
relative to more recent modeling. However, where alternative or older 
modeling generated linkages, even if those linkages differ from 
linkages in the EPA's most recent set of modeling, that information 
provides further evidence, not less, in support of a conclusion that 
the state is required to proceed to Step 3 to further evaluate its 
emissions.
    Therefore, based on the EPA's evaluation of the information 
submitted by West Virginia, and based on the EPA's most recent modeling 
results for 2023, the EPA proposes to find that West Virginia is linked 
at Steps 1 and 2 and has an obligation to assess potential emissions 
reductions from sources or other emissions activity at Step 3 of the 4-
step framework.

[[Page 9526]]

3. West Virginia's Analysis of ``Flexibilities''
    Before proceeding to Step 3 of the analysis, WVDEP examined several 
so-called ``flexibilities'' identified in Attachment A to the EPA's 
March 2018 Memorandum in section 4 of its SIP submission,\44\ 
ostensibly to show that West Virginia should not be seen as 
contributing significantly to certain 2023 nonattainment or maintenance 
receptors identified by the Alpine modeling. Although the Alpine 
modeling is now out of date, and the EPA is primarily relying upon the 
updated 2023 modeling using the 2016v2 emissions platform to inform its 
decision, the EPA has evaluated the ``flexibilities'' discussed by West 
Virginia to see if any of these ideas continue to have relevance to 
this proposed disapproval action.
---------------------------------------------------------------------------

    \44\ See West Virginia 2019 SIP submittal, p. 14.
---------------------------------------------------------------------------

a. HYSPLIT Back Trajectories
    WVDEP evaluated the potential interstate impacts of emissions from 
West Virginia on other states, using HYPLIT modeling. To do so, WVDEP 
considered impacts at the one nonattainment receptor (Harford, MD) and 
three maintenance receptors (Philadelphia, PA; Gloucester, NJ; 
Richmond, NY) to which West Virginia was linked by the Alpine 4-km 
modeling. WVDEP identified the exceedance days for each of those 
receptors during the 2015-2017 time period. For the identified 
exceedance days, West Virginia then used the National Oceanic and 
Atmospheric Administration's (NOAA) Air Resources Laboratory's Hybrid 
Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to 
develop a back trajectory analysis for each day to show the origin of 
air masses and establish emission source-receptor relationships. These 
back trajectory analyses are shown in Appendix H of the West Virginia 
2019 SIP submittal. Using this approach, WVDEP concluded that the 291 
back trajectory analyses ``demonstrate that on the majority of the days 
on which ozone exceedances occurred at the subject receptors, the 
origin of the air masses impacting the receptors did not originate 
within, or pass through, West Virginia's borders in the 48 hours 
preceding the exceedance.'' \45\
---------------------------------------------------------------------------

    \45\ Id. at 17.
---------------------------------------------------------------------------

    The EPA notes that WVDEP's own back trajectory analysis did not 
indicate that there were no cases when air masses associated with 
exceedance days at linked receptors passed over West Virginia. Rather, 
the state claimed that air masses did not move across West Virginia on 
a ``majority'' of the days the State examined ``in the 48 hours 
preceding'' the exceedance. WVDEP further argued that only some of the 
air masses moving across the state moved across ``an industrial area 
where air emissions are more predominate.'' Thus, WVDEP's evaluation of 
HYSPLIT back trajectories still show linkages between some downwind 
exceedances and air masses originating or passing through West 
Virginia.
    In addition, the data in Appendix H of the WVDEP submittal indicate 
that one or more of the daily back trajectories from the Harford, 
Maryland receptor moved across West Virginia on 50 percent of the 
exceedance days between 2015 and 2017 at this receptor. Furthermore, 
the line thickness displayed on trajectory plots does not represent the 
geographic extent of the transported air mass, but rather they 
represent the centerline of an air parcel's motion, calculated to 
understand the trajectory line itself. Uncertainties are clearly 
present in these results and these uncertainties change with trajectory 
time and distance traveled. In this regard, one should avoid concluding 
a region is not along a trajectory's path if the center line of that 
trajectory missed the region by a relatively small distance.\46\ In 
contrast, the EPA's analysis of transported emissions as discussed in 
Section I.C of this document, above, uses updated, photochemical grid 
modeling designed to assess ozone transported to downwind monitors 
across the entire region and over extended timeframes that fully 
account for fate and transport of ozone-precursors over longer 
distances. Thus, the EPA finds that WVDEP's back trajectory analysis 
does not show that West Virginia should not be linked to downwind 
nonattainment or maintenance receptors in 2023.
---------------------------------------------------------------------------

    \46\ See Area Designations for the 2015 Ozone National Ambient 
Air Quality Standards memorandum from Janet G. McCabe to the EPA 
Regional Administrators, February 25, 2016.
---------------------------------------------------------------------------

b. Downwind Air Quality Context
    As the ``context'' surrounding certain downwind receptors, WVDEP 
presented information regarding other local sources of emissions also 
contributing to the nonattainment or maintenance problems at those 
locations. In Section 4.2 of the SIP submittal, WVDEP analyzed various 
types of information.\47\ From this analysis, WVDEP concluded that all 
of the projected receptors in the Alpine modeling are located in 2015 
8-hour ozone NAAQS nonattainment areas within the Interstate 95 highway 
corridor, that high population areas ``closely correspond'' to the 
nonattainment areas, and that high Vehicle Miles Traveled (VMT) also 
``closely correlate'' with the nonattainment areas. WVDEP included a 
more detailed analysis of these factors in Appendix I of the West 
Virginia 2019 SIP Submittal.
---------------------------------------------------------------------------

    \47\ Id.
---------------------------------------------------------------------------

    While the EPA would generally agree that the high VMT along the 
Interstate 95 corridor, along with high population densities in the 
various existing and predicted 2023 nonattainment areas, have a large 
impact on the ozone nonattainment status of these areas, this does not 
prove that West Virginia's emissions do not also contribute to 
nonattainment and maintenance problems at those locations. The fact 
that local sources of emissions also contribute to high ozone levels is 
neither surprising nor outcome determinative. The EPA has developed the 
4-step process to help evaluate whether or not a given state is linked 
to downwind nonattainment and maintenance problems, and that analysis 
starts at the question of whether the state's emissions have a 
projected impact above the 1 percent of the NAAQS threshold in 2023. 
That value at Step 2 is set relatively low in light of the ``collective 
contribution'' problem associated with regional ozone transport. The 
Alpine modeling that WVDEP relied upon shows such impacts above the 
Step 2 threshold from West Virginia at a number of receptors. The more 
recent modeling that the EPA has conducted indicates impacts above that 
threshold at other monitors. Thus, the EPA does not agree that WVDEP's 
analysis of the relative impacts of local sources compared to the 
projected impacts of emissions from the state establishes that West 
Virginia does not significantly contribute to these nonattainment and 
maintenance areas. Nor would the EPA agree that similar arguments about 
the ``context'' of local emissions would apply at the more recently 
identified receptors.
c. International Emissions
    The last consideration noted by WVDEP is Section 179B of the CAA, 
entitled ``International border areas.'' The State focused not on 
section 179B(a), applicable to states that are required to submit 
nonattainment plan SIP submissions to address applicable requirements 
in nonattainment areas, but rather section 179B(b), which applies in 
the case of a state with a designated ozone nonattainment area that 
fails to meet the applicable attainment date and thus may trigger a 
reclassification to the next highest

[[Page 9527]]

classification of ozone nonattainment. Section 179B(b) states: 
``Notwithstanding any other provision of law, any State that 
establishes to the satisfaction of the Administrator that, with respect 
to an ozone nonattainment area in such State, such State would have 
attained the national ambient air quality standard for ozone by the 
applicable attainment date, but for emissions emanating from outside of 
the United States, shall not be subject to the provisions of section 
7511(a)(2) or (5) of this title or section 7511d of this title.'' \48\
---------------------------------------------------------------------------

    \48\ Section 7511(a)(2) relates to the attainment date for 
severe ozone nonattainment areas, and (a)(5) describes the 
conditions necessary for a one-year extension of ozone attainment 
dates. Section 7511d pertains to enforcement for severe and extreme 
ozone nonattainment areas for failure to attain. Neither provision 
is germane to this action.
---------------------------------------------------------------------------

    West Virginia cites a statement in the TSD for the Alpine modeling 
which notes that if anthropogenic emissions from Canada and Mexico, 
tracked as a single tag, are taken into account, then both the EPA and 
Alpine's modeling demonstrate attainment at the Harford Maryland 
receptor with the 2015 ozone NAAQS.\49\ In other words, simply 
subtracting the projected impact of international emissions from Canada 
and Mexico at that receptor would result in ``attainment'' at that 
location. WVDEP asserts that this fact would allow the State to ``stop 
at Step 1 of the four-factor process.'' EPA notes that WVDEP only 
raised this issue with respect to the nonattainment receptor it 
identified in Harford, Maryland, rather than the maintenance receptors, 
presumably in recognition of the fact that section 179B(b) pertains to 
nonattainment areas, rather than maintenance areas.
---------------------------------------------------------------------------

    \49\ Id. at p. 20.
---------------------------------------------------------------------------

    The EPA disagrees with the theory that section 179B applies in this 
way. First, the EPA notes that section 179B(b), relied upon and quoted 
by WVDEP, has no bearing on the issue of interstate transport as 
posited in the State's SIP submission. That specific statutory 
provision, by its explicit terms, only applies in the event a state 
with a designated ozone nonattainment area fails to attain the NAAQS by 
the applicable attainment date. If, in those circumstances, the state 
at issue would have attained the NAAQS but for the impacts of 
international transport, then that state may seek to avoid 
reclassification to the next level of ozone nonattainment that would 
otherwise occur upon the EPA making the requisite finding of failure to 
attain. WVDEP misapplies section 179B(b) when it suggests that it 
alters the State's obligations with respect to section 110(a)(D)(i)(I), 
using the example of the impacts at the Harford Maryland receptor 
identified in the Alpine modeling. However, even if Maryland could in 
the future seek to invoke section 179B(b), the only effect would be to 
excuse Maryland from certain additional nonattainment plan requirements 
of CAA sections 7511(a)(2) and (5) and 7511D. Further, if Maryland were 
to do so, the mere existence of international transport impacts would 
not be outcome determinative--even in that context where CAA section 
179B(b) actually applies.\50\ Section 179B does not supplant the 
separate obligation of upwind states such as West Virginia to address 
their interstate transport impacts on other downwind states. It is a 
separate provision of the CAA intended to address the impacts of 
international emissions on nonattainment areas.
---------------------------------------------------------------------------

    \50\ See Guidance on the Preparation of Clean Air Act Section 
179B Demonstrations for Nonattainment Areas Affected by 
International Transport of Emissions (December 2020), pages 10-12, 
available at https://www.epa.gov/sites/default/files/2020-01/documents/draft_179b_guidance-final_draft_for_posting.pdf.
---------------------------------------------------------------------------

    Second, and more importantly, West Virginia's reasoning related to 
international emissions is inapplicable to the requirements of CAA 
section 110(a)(2)(D)(i)(I). The good neighbor provision requires states 
and the EPA to address interstate transport of air pollution that 
contributes to downwind states' ability to attain and maintain NAAQS. 
Whether emissions from other states or other countries also contribute 
to the same downwind air quality issue is irrelevant in assessing 
whether a downwind state has an air quality problem, or whether an 
upwind state is significantly contributing to that problem. States are 
not obligated under CAA section 110(a)(2)(D)(i)(I) to reduce emissions 
sufficient on their own to resolve downwind receptors' nonattainment or 
maintenance problems. Rather, states are obligated to eliminate their 
own ``significant contribution'' or ``interference'' with the ability 
of other states to attain or maintain the NAAQS.
    Indeed, the D.C. Circuit in Wisconsin specifically rejected 
petitioner arguments suggesting that upwind states should be excused 
from good neighbor obligations on the basis that some other source of 
emissions (whether international or another upwind state) could be 
considered the ``but-for'' cause of downwind air quality problem. 938 
F.3d 303 at 323-324. The court viewed petitioners' arguments as 
essentially an argument ``that an upwind State `contributes 
significantly' to downwind nonattainment only when its emissions are 
the sole cause of downwind nonattainment.'' 938 F.3d 303 at 324. The 
court explained that ``an upwind State can `contribute' to downwind 
nonattainment even if its emissions are not the but-for cause.'' Id. at 
324-325. See also Catawba County v. EPA, 571 F.3d 20, 39 (D.C. Cir. 
2009) (rejecting the argument ``that `significantly contribute' 
unambiguously means `strictly cause' '' because there is ``no reason 
why the statute precludes EPA from determining that [an] addition of 
[pollutant] into the atmosphere is significant even though a nearby 
county's nonattainment problem would still persist in its absence''); 
Miss. Comm'n o Envtl. Quality v. EPA, 790 F.3d 138, 163 n.12 (D.C. Cir. 
2015) (observing that the argument that ``there likely would have been 
no violation at all . . . if it were not or the emissions resulting 
from [another source]'' is ``merely a rephrasing of the but-for 
causation rule that we rejected in Catawba County.''). Therefore, a 
state is not excused from eliminating its significant contribution on 
the basis that international emissions also contribute some amount of 
pollution to the same receptors to which the State is linked.
    Therefore, the EPA proposes to find that Section 179B(b) of the CAA 
does not serve to alleviate West Virginia of any potential obligations 
under Section 110(a)(2)(D)(i)(I).
    EPA will proceed to evaluate the information and analysis WVDEP 
provided at Step 3 of the 4-step interstate transport framework.
4. Evaluation of Information Provided Regarding Step 3
    At Step 3 of the 4-step interstate transport framework, the state 
should further evaluate its sources of emissions that may impact the 
relevant downwind receptors, in light of multiple factors, including 
air quality and cost considerations, to determine what, if any, 
emissions significantly contribute to nonattainment or interfere with 
maintenance and, thus, must be eliminated under CAA section 
110(a)(2)(D)(i)(I).
    To evaluate effectively which emissions in the state should be 
deemed ``significant'' and therefore prohibited, states generally 
should prepare an accounting of sources and other emissions activity 
for relevant pollutants and assess potential, additional emissions 
reduction opportunities and resulting downwind air quality 
improvements. The EPA has consistently applied this general approach 
(i.e., Step 3 of the 4-step

[[Page 9528]]

interstate transport framework) when identifying emissions 
contributions that the Agency has determined to be ``significant'' (or 
interfere with maintenance) in each of its prior Federal, regional 
ozone transport rulemakings, and this interpretation of the statute has 
been upheld by the Supreme Court. See EME Homer City, 572 U.S. 489, 519 
(2014). While the EPA has not directed states that they must conduct a 
Step 3 analysis in precisely the manner the EPA has done in its prior 
regional transport rulemakings, state implementation plans addressing 
the obligations in CAA section 110(a)(2)(D)(i)(I) must prohibit ``any 
source or other type of emissions activity within the State'' from 
emitting air pollutants which will contribute significantly to downwind 
air quality problems. Thus, states must complete something similar to 
the EPA's analysis (or an alternative approach to defining 
``significance'' that comports with the statute's objectives) to 
determine whether and to what degree emissions from a state should be 
``prohibited'' to eliminate emissions that will ``contribute 
significantly to nonattainment in, or interfere with maintenance of,'' 
the NAAQS in any other state.
    In Step 3, West Virginia evaluated statewide NOX 
emissions data from the triennial National Emissions Inventory (NEI) 
for 2008, 2011, 2014 and 2017, as updated on August 2, 2018, on the 
EPA's NEI Air Pollution Emissions Trends Data website. This website 
provides current emissions trends data for all Tier 1 Categories of 
NOX emissions from 1990 through 2020.\51\ WVDEP's analysis 
found that of the Tier 1 Categories, six of those categories 
represented 95% of the total 2017 NOX emissions from sources 
in the State. These categories are: (i) Fuel Combustion--Electric 
Utilities (29.5%); (ii) Fuel Combustion--Industrial (9.1%); (iii) Fuel 
Combustion--Other (4.8%); (iv) Petroleum and Related Industries 
(22.8%); (v) Highway Vehicles (21.5%); (vi) and Off-Highway (7.6%). 
West Virginia therefore focused its Step 3 control and cost analysis on 
these six categories of sources.
---------------------------------------------------------------------------

    \51\ At the time West Virginia submitted its SIP in 2019, NEI 
data for 2020 was not available, so West Virginia limited its 
analysis to data available at that time.
---------------------------------------------------------------------------

a. Highway Vehicles and Off-Highway
    West Virginia's analysis of NEI data indicated that these two Tier 
1 source categories combined produced 29.1% of the NOX 
emissions in the State in 2017. For these categories of mobile sources, 
WVDEP noted that such sources are regulated at the Federal level and 
not the state level, so WVDEP concluded that no further analysis of the 
Highway Vehicles and Off-Highway categories for additional potential 
reductions is required. In Section 6.1 of the SIP submission, WVDEP 
noted and described a number of EPA programs designed to reduce 
NOX emissions from mobile sources, including the 2007 Heavy-
Duty Highway Rule (40 CFR part 86, subpart P); the Tier 2 Vehicle and 
Sulfur Program (40 CFR part 80, subpart H; 40 CFR part 85, 40 CFR part 
86), Tier 3 Motor Vehicle Emission and Fuel Standards (40 CFR parts 79, 
80, 85, 86, 600, 1036, 1037, 1042, 1048, 1054, 1065, and 1066); Tier 4 
Vehicle Standards; and the Nonroad Diesel Emissions Program (40 CFR 
part 89).
    Given the magnitude of NOX emission reductions in West 
Virginia reflected in the NEI, the EPA agrees that it is appropriate 
for WVDEP to evaluate these source categories for potential additional 
controls to reduce interstate transport for the purposes of the 2015 8-
hour ozone NAAQS. The EPA does not agree, however, with the State's 
attempt to categorize certain sectors of emissions as per se beyond its 
regulatory control. Clearly the State possesses regulatory authority 
over many categories of sources and other types of ``emissions activity 
within the state,'' see CAA section 110(a)(2)(D)(i). While the EPA 
generally regulates mobile sources at the Federal level under title II 
of the CAA, the state also has the authority to undertake any number of 
measures to reduce emissions from mobile sources through means and 
techniques that are not preempted by title II. See, e.g., CAA sections 
182(b)(3), 182(b)(4), 182(c)(3), 182(c)(4), 182(c)(5), 182(d)(1), 
182(e)(3), and 182(e)(4) (identifying programs to control mobile source 
emissions that states are required to implement depending on the degree 
of ozone nonattainment). Pursuant to CAA section 116, states retain 
authority to regulate sources in SIPs, and to do so more stringently 
than the EPA, unless preempted. For example, many states, including 
states with receptors to which West Virginia is linked, have adopted 
California motor vehicle standards as permitted under CAA section 
177.\52\
---------------------------------------------------------------------------

    \52\ California Air Resources Board, States That Have Adopted 
California's Vehicle Standards Under Section 177 of the Federal 
Clean Air Act (Current as of December 6, 2021), https://ww2.arb.ca.gov/resources/documents/states-have-adopted-californias-vehicle-standards-under-section-177-federal.
---------------------------------------------------------------------------

    WVDEP's listing of existing Federal control measures for mobile 
sources does not in and of itself serve as an adequate substitute for a 
Step 3 analysis of additional potential emission reductions. First, 
these standards, to the extent they are ``on-the-books,'' are already 
reflected in the base case air quality modeling conducted at Steps 1 
and 2. Further, the listing of existing or on-the-way control measures, 
whether approved into the State's SIP or not, does not substitute for a 
complete Step 3 analysis under the EPA's 4-step framework to define 
``significant contribution.''
b. Petroleum and Related Industries
    For the Petroleum and Related Industries Tier 1 category, WVDEP's 
analysis indicated that sources of this type produced 22.8% of the 2017 
NOX emissions in the State. West Virginia further 
acknowledged that this category has been a growing source of emissions 
in more recent years, but argued that West Virginia's New Source Review 
(NSR) permitting programs will adequately ensure that emissions from 
any new or modified sources in this category do not cause or contribute 
to nonattainment of the NAAQS.\53\ West Virginia has a PSD program that 
requires new or modified major stationary sources located in designated 
attainment areas to obtain a permit and impose emission controls that 
meet the best available control technology (BACT) level of control. 
Similarly, West Virginia has a Nonattainment NSR program that requires 
new or modified major stationary sources located in designated 
nonattainment areas to obtain a permit and impose emission controls 
that meet the lowest achievable emission rate (LAER) level of control. 
WVDEP asserts that the BACT and LAER requirements are by definition 
more stringent than the RACT/RACM level of control required in 
nonattainment plans that states must impose in designated nonattainment 
areas. As a component of these permitting programs, the State noted 
that there is also a requirement to consider whether the emissions from 
the source ``will interfere with attainment or maintenance of an 
applicable ambient air quality standard.'' The State therefore did not 
perform an analysis of potential additional control measures or costs 
for this category of sources.
---------------------------------------------------------------------------

    \53\ Id. at 25.
---------------------------------------------------------------------------

    The EPA agrees with WVDEP's identification of the sources in the 
Petroleum and Related Industries category from the NEI as sufficiently 
significant to warrant evaluation for NOX emission controls. 
As the State reflected in its SIP submission, the

[[Page 9529]]

cumulative NOX emissions from this category comprise 22.8% 
of West Virginia's emissions, and thus a proportion of emissions second 
only to the category that includes EGUs. Further, WVDEP acknowledged 
that unlike other source categories, the NOX emissions from 
this category have been increasing in recent years. In Table 6 of the 
SIP submission, the State reflected the large increase in such 
emissions from 2008 through 2017.
    Notwithstanding these increases in emissions, WVDEP relies 
primarily on the existing permitting programs (minor source, PSD, and 
NNSR) as the basis for concluding that no further controls would be 
necessary for these sources to address interstate transport problems 
for purposes of the 2015 8-hour ozone NAAQS. First, WVDEP seems to have 
done no more than describe the general framework for new source 
permitting that is mandated of all states under the CAA and has not 
identified how its state programs in particular go beyond those basic 
requirements in any manner relevant to ozone transport. Nonetheless, 
the State is correct that these permitting programs do impose control 
requirements (e.g., BACT or LAER) and do require an analysis of 
potential impacts on attainment and maintenance of the NAAQS. But there 
are likewise important distinctions between the permitting program 
requirements and interstate transport requirements, including but not 
limited to: (i) The permitting programs generally apply only to new 
sources or major modification of existing sources; (ii) the evaluation 
of impacts on attainment and maintenance in other states in the context 
of a permit for a single source may not be as robust and have the same 
geographic scope as that undertaken by states and the EPA for purposes 
of section 110(a)(2)(D)(i)(I); and (iii) the timing of the permitting 
process evaluation may have no bearing on the NAAQS at issue (i.e., a 
permit issued in 2005 would not have considered impacts vis a vis the 
2015 8-hour ozone NAAQS). Further, existing sources may have been 
permitted under a new source permitting program years or even decades 
ago, before more effective or cheaper emissions control technologies 
became available.
    Thus, even if the permitting programs address new sources of 
emissions for the intended purposes of those programs, it does not 
necessarily follow that they automatically meet all other CAA 
requirements as well. The EPA disagrees, therefore, with the conclusion 
that the existence of these permitting programs resolves the issue of 
whether there are additional control measures that the State should 
impose specifically for purposes of eliminating significant 
contribution to nonattainment or interference with maintenance at 
downwind receptors for the 2015 8-hour ozone NAAQS.\54\
---------------------------------------------------------------------------

    \54\ The EPA notes that WVDEP has not explained why new source 
permitting was a sufficient control measure for interstate ozone 
transport from the ``Petroleum and Related Industries'' category, 
but not other source categories, when the new source permitting 
requirements apply to all new sources.
---------------------------------------------------------------------------

    In general, the listing of existing or on-the-way control measures, 
whether approved into the State's SIP or not, does not substitute for a 
complete Step 3 analysis under EPA's 4-step framework to define 
``significant contribution.'' WVDEP did not provide an assessment of 
the overall effects of these measures, when the emissions reductions 
would be achieved, and what the overall resulting air quality effects 
would be at identified out of state receptors. WVDEP did not evaluate 
additional, potential emissions control opportunities, or their costs 
or impacts, or attempt to analyze whether, if applied more broadly 
across linked states, the emissions reductions would constitute the 
elimination of significant contribution. Although the EPA acknowledges 
states are not necessarily bound to follow its own analytical framework 
at Step 3, we note that WVDEP did not do a meaningful analysis of what 
other potential controls may be necessary to achieve NOX 
emission reductions from these sources for the 2015 ozone NAAQS. This 
would have been similar to the approach to defining significant 
contribution that EPA has applied in prior rulemakings such as CSAPR 
and or the CSAPR Update, even if such an analysis is not technically 
mandatory.
c. Fuel Combustion--Electric Utilities
    West Virginia's analysis of NEI data indicated that EGUs produced 
30.2% of the NOX emissions in the State in 2017.\55\ The 
State noted that NOX emissions from EGUs have already 
declined as a result of other CAA requirements, such as the Acid Rain 
Program, the NOX Budget Trading Program, the CAIR, and the 
CSAPR programs. As a result of these programs and actions, WVDEP 
estimated a reduction in ozone season emissions of 75 percent, or 
almost 2 million tons, since 1997. The EPA acknowledges that these 
existing programs have already reduced NOX emissions 
substantially from EGUs, but the question at issue at this time is 
whether more NOX emissions reductions are necessary from 
such sources for purposes of CAA section 110(a)(2)(D)(i)(I) for the 
2015 8-hour ozone NAAQS. Notwithstanding the past reductions of 
NOX from EGUs, WVDEP correctly concluded that further 
analysis of potential controls is necessary.
---------------------------------------------------------------------------

    \55\ The narrative text of West Virginia's SIP submission at 
page 27 says that EGUs contribute 30.2%, while Table 6 of the SIP 
submission identifies the EGU contribution as 29.5%. This difference 
in attributed contribution does not change the outcome of EPA's 
analysis.
---------------------------------------------------------------------------

    As one part of this analysis, West Virginia relied on the shutdown 
of specific EGUs that would further reduce NOX emissions 
from the state. West Virginia identified the retirements of six coal-
fired power plants (consisting of 17 units total) that have occurred in 
recent years. Three power plants shut down in September 2012. Three 
additional power plants shut down in June 2015. WVDEP provided 
documentation for these units showing that the units were permanently 
retired, and the Title V permits were surrendered. The State further 
indicated that should operations resume at any of the shut-down units 
in the future, the source \56\ would have to complete the permitting 
process as a new facility.
---------------------------------------------------------------------------

    \56\ The documentation is in Appendix M of West Virginia's 2019 
SIP submittal.
---------------------------------------------------------------------------

    The EPA agrees that these shutdowns will eliminate NOX 
emissions from these sources, and thus this may help to reduce the 
impacts of such emissions from West Virginia at the identified 
nonattainment and maintenance receptors. Evaluation of further control 
of these specific EGU sources is not required. However, EPA's most 
recent 2016v2 emissions platform-based modeling has already taken these 
shutdowns into account, and projects impacts at nonattainment or 
maintenance receptors in Connecticut, New York, and Maryland 
notwithstanding these reductions in emissions. Further, the mere fact 
that a particular EGU has shutdown does not mean that all associated 
emissions should be subtracted from the total inventory of a state's 
emissions. Typically, a shutdown is accompanied by a shift in 
generation to new sources or existing sources with available capacity, 
which in turn produces some incremental increase in emissions at those 
sources. WVDEP did not analyze the net emissions effects of the 
shutdowns it listed. By contrast, in its most recent modeling, the EPA 
has thoroughly and comprehensively evaluated emissions from EGUs in 
West Virginia and other states. The EPA's latest projections of the 
baseline EGU emissions uses the version 6--Summer 2021 Reference Case 
of the Integrated Planning Model (IPM). IPM is a multi-

[[Page 9530]]

regional, dynamic, and deterministic linear programming model of the 
U.S. electric power sector.\57\ The model provides forecasts of least 
cost capacity expansion, electricity dispatch, and emission control 
strategies, while meeting energy demand, environmental, transmission, 
dispatch, and reliability constraints.
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    \57\ Detailed information and documentation of EPA's Base Case, 
including all the underlying assumptions, data sources, and 
architecture parameters can be found on EPA's website at: https://www.epa.gov/airmarkets/epas-power-sector-modeling-platform-v6-using-ipm-summer-2021-reference-case.
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    The IPM version 6--Summer 2021 Reference Case incorporated recent 
updates through the Summer of 2021 to account for updated Federal and 
State environmental regulations for EGUs. This projected base case 
accounts for the effects of the finalized Mercury and Air Toxics 
Standards rule, CSAPR, the CSAPR Update, the Revised CSAPR Update, New 
Source Review settlements, the final effluent limitation guidelines 
(ELG) Rule, the coal combustion residual (CCR) Rule, and other on-the-
books Federal and State rules (including renewable energy tax credit 
extensions from the Consolidated Appropriations Act of 2021) through 
early 2021 impacting SO2, NOX, directly emitted 
particulate matter, CO2, and power plant operations. It also 
includes final actions EPA has taken to implement the Regional Haze 
Rule and best available retrofit technology (BART) requirements. 
Further, the IPM Platform v6 uses demand projections from the Energy 
Information Agency's (EIA) Annual Energy Outlook (AEO) 2020.\58\
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    \58\ Detailed information and documentation of EPA's Base Case, 
including all the underlying assumptions, data sources, architecture 
parameters, and IPM comments form can be found on EPA's website at: 
https://www.epa.gov/airmarkets/epas-power-sector-modeling-platform-v6-using-ipm-summer-2021-reference-case.
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    The IPM version 6--Summer 2021 Reference Case uses the National 
Electric Energy Data System (NEEDS) v6 database as its source for data 
on all existing and planned-committed units. Units are removed from the 
NEEDS inventory only if a high degree of certainty could be assigned to 
future implementation of the announced future closure or 
retirement.\59\ The available retirement-related information was 
reviewed for each unit, and the following rules are applied to remove:
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    \59\ The ``Capacity Dropped'' and the ``Retired Through 2023'' 
worksheets in NEEDS lists all units that are removed from the NEEDS 
v6 inventory--NEEDS v6 Summer 2021 Reference Case. This data can be 
found on EPA's website at: https://www.epa.gov/airmarkets/national-electric-energy-data-system-needs-v6.

    (i) Units that are listed as retired in the December 2020 EIA 
Form 860M;
    (ii) Units that have a planned retirement year prior to June 30, 
2023 in the December 2020 EIA Form 860M;
    (iii) Units that have been cleared by a regional transmission 
operator (RTO) or independent system operator (ISO) to retire before 
2023, or whose RTO/ISO clearance to retire is contingent on actions 
that can be completed before 2023;
    (iv) Units that have committed specifically to retire before 
2023 under Federal or state enforcement actions or regulatory 
requirements; and
    (v) Finally, units for which a retirement announcement can be 
corroborated by other available information. Units required to 
retire pursuant to enforcement actions or state rules on July 1, 
2023 or later are retained in NEEDS v6.

    Retirement of EGU units that follow this process are excluded from 
the NEEDS inventory. This includes EGU units as highlighted in the West 
Virginia SIP submission (Appendix G and Appendix M).\60\ Thus, the 
modeling already accounts for the NOX emission reductions in 
West Virginia that resulted from the source shutdowns identified by 
WVDEP. Further, closures taking place on or after July 1, 2023 are 
captured as constraints on those units in the IPM modeling, and the 
units are retired in future year projections per the terms of the 
related requirements.
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    \60\ The ``Capacity Dropped'' and the ``Retired Through 2023'' 
worksheets in NEEDS lists all units that are removed from the NEEDS 
v6 inventory--NEEDS v6 Summer 2021 Reference Case. This data can be 
found on EPA's website at: https://www.epa.gov/airmarkets/national-electric-energy-data-system-needs-v6.
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    As a second part of its Step 3 evaluation of potential controls for 
EGUs, West Virginia also relied on the EPA's own analysis of potential 
NOX emission reductions in connection with the CSAPR Update 
for the 2008 ozone NAAQS. WVDEP noted that the EPA itself considered 
the adequacy of NOX controls for EGUs as part of the CSAPR 
Update rulemaking. The State pointed to the EPA's analytical process in 
the CSAPR Update rulemaking concerning factors such as cost, available 
emissions reductions, and downwind air impacts, and the resulting 
emission budgets that EPA derived using the ``knee in the curve'' 
evaluation of cost effectiveness as described in the proposed 
``Determination Regarding Good Neighbor Obligations for the 2008 Ozone 
National Ambient Air Quality Standard.'' In particular, WVDEP 
emphasized the EPA statement in the proposal that it ``considers the 
turning on and optimizing of existing SCR controls and the installation 
of combustion controls to be NOX control strategies that 
have already been appropriately evaluated and implemented in the final 
CSAPR Update.'' The State also pointed to the EPA's proposed CSAPR 
Close-Out Rule, in which the EPA similarly stated, ``the EPA considers 
the turning on and optimizing of existing SCR controls and the 
installation of combustion controls to be NOX control 
strategies that have already been appropriately evaluated and 
implemented in the final CSAPR Update.''
    In support of this argument, WVDEP also included a Table containing 
the ozone season NOX emission rates in 2017 and 2018 for EGU 
sources located in West Virginia. Table 7 presents information about 
the size, fuel type, control type, and emission rates in pounds (lbs) 
per million British thermal unit (MMBtu) (lbs/MMBtu). This table 
provides key information about the existing control measures and 
emission rates for these individual sources, at the time of the SIP 
submission. However, WVDEP does not provide analysis of any potential 
additional or strengthened control measures at these sources, that may 
or may not be needed for purposes of the 2015 8-hour ozone NAAQS.
    Finally, for EGUs, WVDEP asserted that because the EPA's CSAPR 
Update concluded that all identified highly cost-effective emission 
reductions have already been implemented with respect to EGUs for the 
2008 ozone NAAQS, no additional highly cost-effective reductions are 
available for EGUs for the 2015 8-hour ozone NAAQS. WVDEP argues that 
because its EGUs are subject to the CSAPR Update (which reflected a 
stringency at the nominal marginal cost threshold of $1400/ton (2011$) 
for the 2008 ozone NAAQS), it has already implemented all cost-
effective emissions reductions for its EGU fleet.
    The EPA disagrees. First, the so-called CSAPR Close-Out has been 
vacated for unlawfully permitting significant contribution to continue 
beyond the next attainment date. New York v. EPA, 781 Fed. App'x 4 
(D.C. Cir. 2019). See also Wisconsin, 938 F.3d at 318-20. Second, in 
the CSAPR Update, EPA had promulgated only a partial remedy as to EGUs 
even with respect to the less stringent 2008 ozone NAAQS, a conclusion 
affirmed by the D.C. Circuit in New York v. EPA, 964 F.3d 1214, 1225 
(D.C. Cir. 2020). EPA has recently completed action on remand from the 
Wisconsin decision and has promulgated a full remedy as to West 
Virginia's obligations for the 2008 ozone NAAQS in the Revised CSAPR 
Update. EPA found that additional, cost-effective emissions reductions 
from West Virginia's EGUs were indeed necessary to resolve its 
obligations under the 2008

[[Page 9531]]

ozone NAAQS, see 86 FR 23054, 23100, 23123-24 (April 30, 2021). 
Therefore, WVDEP's conclusions that no further cost-effective emission 
reductions are available from its EGUs cannot be sustained.
    More fundamentally, relying on the CSAPR Update's (or any other CAA 
program's) determination of cost-effectiveness without further Step 3 
analysis is insufficient. Cost-effectiveness must be assessed in the 
context of the specific CAA program; assessing cost-effectiveness in 
the context of ozone transport should reflect a more comprehensive 
evaluation of the nature of the interstate transport problem, the total 
emissions reductions available at several cost thresholds, and the air 
quality impacts of the reductions at downwind receptors. While the EPA 
has not established a benchmark cost-effectiveness value for the 2015 
8-hour ozone NAAQS interstate transport obligations, because the 2015 
8-hour ozone NAAQS is a more stringent and more protective air quality 
standard, it is reasonable to expect control measures or strategies to 
address interstate transport under this NAAQS to reflect higher 
marginal control costs. As such, the marginal cost threshold of $1,400/
ton for the CSAPR Update (which addresses the 2008 ozone NAAQS and is 
in 2011$) is not an appropriate cost threshold and cannot be approved 
as a benchmark to use for interstate transport SIP submissions for the 
2015 8-hour ozone NAAQS.
    In addition, the updated 2016v2 emissions platform captures all 
existing CSAPR trading programs in the baseline, and that modeling 
confirms that these control programs were not sufficient to eliminate 
West Virginia's linkage at Steps 1 and 2 under the 2015 8-hour ozone 
NAAQS. Although the state provided an inventory of existing controls on 
its EGU fleet, based on updated modeling results, the State was 
therefore obligated at Step 3 to assess additional control measures 
using a multifactor analysis.
d. Fuel Combustion--Industrial and Fuel Combustion--Other
    WVDEP's analysis indicated that NOX emissions from non-
EGU sources in two other NEI source categories, Fuel Combustion--
Industrial and Fuel Combustion--Other, together comprised 13.9% of the 
NOX emissions in West Virginia in 2017. For non-EGU sources 
of NOX emissions, WVDEP similarly reviewed EPA documentation 
for the CSAPR Update, specifically a cost-effectiveness evaluation 
provided by SRA International (SRA), which was contracted by the EPA to 
perform this analysis. The analysis split the sources subject to the 
cost-effectiveness analysis into two groups: Sources with 
NOX emissions greater than 100 tons per year (tpy) in 2017, 
and sources with NOX emissions between 25 and 100 tpy in 
2017. The analysis then reviewed these sources using a $10,000 per ton 
cost effectiveness threshold. In West Virginia, the analysis identified 
nine emissions units in the ``greater than 100 tpy'' group and 21 
emission units in the ``25 to 100 tpy'' group for further evaluation 
based on potential for controls.
    Of the nine ``greater than 100 tpy'' units, WVDEP noted that four 
had permanently shutdown, two were subject to a Consent Order to 
shutdown by December 31, 2021, and one was subject to a Consent Order 
which established a 0.20 lbs/MMBtu during the ozone season. For the 
remaining two sources, WVDEP claims that the EPA determined in the 
CSAPR Close-Out Rule that one source was well controlled and the other 
did not have any technically and economically available controls. 
However, EPA made no such determinations with respect to any non-EGUs 
in the CSAPR Close-Out. Of the 21 ``25 to 100 tpy'' units, WVDEP noted 
that six units have permanently shutdown and three are subject to a 
Consent Order to shutdown by December 31, 2021.\61\ West Virginia's SIP 
submission concludes that ``[t]he shutdown of the identified 10 
sources; the required shutdown of the additional five sources; and the 
current level of control on the remaining 20 sources, in conjunction 
with the implementation of the Control Measures programs listed in 
Section 6, represent the implementation of reasonable control measures 
in West Virginia.'' \62\
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    \61\ See Appendix N of West Virginia's SIP submittal.
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    Given that the emissions from these source categories comprise 
13.9% of the total NOX emissions from West Virginia in the 
2017 NEI, the EPA agrees that it is appropriate for WVDEP to evaluate 
them. The EPA does not, however, agree with this analysis for certain 
non-EGU sources. First, many of the source shutdowns identified by West 
Virginia have generally been captured in the data the EPA used to 
perform the 2016v2 emissions platform-based modeling. Even with the 
shutdowns, the results of that updated modeling continue to show that 
West Virginia's sources contribute to nonattainment and maintenance 
receptors. Moreover, because the 2015 8-hour ozone NAAQS is more 
stringent than the 2008 ozone NAAQS, the EPA's findings of an 
acceptable cost threshold for controls (which did not include non-EGUs) 
in the CSAPR Update, which only addresses transport for the 2008 ozone 
NAAQS, are not sufficient to evaluate whether West Virginia has adopted 
all reasonable control measures for these non-EGU sources for purposes 
of the 2015 8-hour ozone NAAQS. Additional reductions above and beyond 
those amounts may be needed for a more stringent 2015 8-hour ozone 
NAAQS, so WVDEP's analysis showing the NOX reductions 
attributable to sources shutdown since 2011 did not address the 
quantity of additional reductions that may be needed from these types 
of sources for purposes of meeting section 110(a)(2)(D)(i)(I) 
requirements for the 2015 8-hour ozone NAAQS. Although the State 
provided an inventory of non-EGU sources based on previous CoST 
outputs, the State did not assess additional control measures using a 
multifactor analysis for sources that were not shut down, not under the 
obligations of a consent order, or were not considered well controlled 
based on the EPA's assessment. The inventory of non-EGU stationary 
sources included in EPA's most recent emissions inventory indicates 
that there are a number of such sources that continue to emit 
NOX in excess of 100 tpy.\63\ WVDEP conducted no analysis of 
additional emissions control opportunities at these sources.
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    \63\ See ``wv_og_nonegu_unit_comparison_16_17_18_19_20.xlsx'' in 
Docket ID No. EPA-R03-OAR-2021-0873.
---------------------------------------------------------------------------

    Finally, relying on a FIP at Step 3 is per se not approvable if the 
state has not adopted that program into its SIP and instead continues 
to rely on the FIP. States may not rely on non-SIP measures to meet SIP 
requirements. See CAA section 110(a)(2)(D) (``Each such [SIP] shall . . 
. contain adequate provisions. . . .''). See also CAA section 
110(a)(2)(A); Committee for a Better Arvin v. U.S. E.P.A., 786 F.3d 
1169, 1175-76 (9th Cir. 2015) (holding that measures relied on by state 
to meet CAA requirements must be included in the SIP). In this matter, 
West Virginia has adopted a state regulation, 45CSR43,\64\ 
incorporating by reference 40 CFR part 97, subparts AAAAA, CCCCC, and 
EEEEE, which are the CSAPR NOX Annual, SO2 Group 
1, and Ozone Season NOX trading programs. The State designed 
the SIP submission to incorporate into the West Virginia SIP the 
requirements of the CSAPR Update

[[Page 9532]]

Group 2 trading program, in order to meet the State's obligations under 
the good neighbor provision for the 2008 ozone NAAQS. WVDEP submitted 
this as a SIP revision to the EPA on June 5, 2019, and the EPA proposed 
approval of the revision.\65\ However, following EPA's proposed 
approval of this SIP submission, a court decision and EPA's subsequent 
rulemaking in the Revised CSAPR Update have rendered it inadequate. As 
explained in Section I of this document, the D.C. Circuit issued a 
decision in Wisconsin v. EPA, remanding the CSAPR Update because the 
EPA had failed to require upwind states to eliminate their significant 
contribution by the next applicable attainment date by which downwind 
states must come into compliance with the NAAQS, as established under 
CAA section 181(a). 938 F.3d at 313. The EPA has since issued the 
Revised CSAPR Update, which released updated budgets and requirements 
for states, including West Virginia, in order to fully resolve 
interstate transport obligations for the 2008 ozone NAAQS. As such, the 
ozone season NOX budgets in the West Virginia SIP submission 
for which the EPA proposed approval no longer satisfy the State's 
interstate transport obligations under the 2008 ozone NAAQS. The EPA is 
not in this action addressing the pending June 5, 2019 SIP submission 
and will address it in a separate action. The EPA encourages West 
Virginia to withdraw the June 5, 2019 SIP submission.
---------------------------------------------------------------------------

    \64\ See ``Cross State Air Pollution Rule to Control Annual 
Nitrogen Oxide Emissions, Annual Sulfur Dioxide Emissions, and Ozone 
Season Nitrogen Oxide Emission,'' at https://dep.wv.gov/daq/publicnoticeandcomment/Documents/45CSR43Prop_wAttachments.pdf.
    \65\ See 84 FR 41944 (August 16, 2019).
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5. Evaluation of Information Provided Regarding Step 4
    Step 4 of the 4-step interstate transport framework calls for 
development of permanent and federally enforceable control strategies 
to achieve the emissions reductions determined to be necessary at Step 
3 to eliminate significant contribution to nonattainment or 
interference with maintenance of the NAAQS. As mentioned previously, 
WVDEP's SIP submission did not contain an evaluation of additional 
emission control opportunities or establish that no additional controls 
are required beyond their existing controls and regulatory mechanisms 
to eliminate significant contribution to nonattainment or interference 
with maintenance of the 2015 8-hour ozone NAAQS. WVDEP additionally 
identified the incorporation by reference into its SIP certain emission 
budgets and trading programs created by CSAPR and the CSAPR Update and 
the EPA's pending final action on this proposed SIP revision to meet 
its requirements for the good neighbor provisions under the 2015 8-hour 
ozone NAAQS. However, as explained in our evaluation of Step 3 of 
WVDEP's 2019 SIP submittal, we do not agree that the requirements of 
the CSAPR Update satisfy West Virginia's good neighbor obligations 
under the 2015 8-hour ozone NAAQS (or the 2008 ozone NAAQS). 
Additionally, the budgets and trading programs created by CSAPR and the 
CSAPR Update is not a new measure with new requirements, as the FIP 
implementing these programs has been in effect for several years and 
the emissions reductions associated have been taken into account in the 
EPA's modeling of 2023 nonattainment and maintenance receptors using 
the 2016v2 emissions platform. As a result, EPA proposes to disapprove 
West Virginia's submittal on the separate, additional basis that the 
State has not developed the appropriate permanent and enforceable 
emissions reductions necessary to meet the obligations of CAA section 
110(a)(2)(d)(i)(I).
6. Conclusion
    Based on the EPA's evaluation of West Virginia's SIP submission, 
the EPA is proposing to find that West Virginia's February 4, 2019 SIP 
submission addressing CAA section 110(a)(2)(D)(i)(I) does not meet the 
State's interstate transport obligations, because it fails to contain 
the necessary provisions to eliminate emissions that will contribute 
significantly to nonattainment or interfere with maintenance of the 
2015 8-hour ozone NAAQS in any other state.

IV. Proposed Action

    We are proposing to disapprove West Virginia's February 4, 2019 SIP 
submission pertaining to interstate transport of air pollution which 
will significantly contribute to nonattainment or interfere with 
maintenance of the 2015 8-hour ozone NAAQS in other states. Under CAA 
section 110(c)(1), disapproval would establish a 2-year deadline for 
the EPA to promulgate a FIP for West Virginia to address the CAA 
section 110(a)(2)(D)(i)(I) interstate transport requirements pertaining 
to significant contribution to nonattainment and interference with 
maintenance of the 2015 8-hour ozone NAAQS in other states, unless the 
EPA approves a new West Virginia SIP submission that meets these 
requirements. Disapproval does not start a mandatory sanctions clock 
for West Virginia.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action as defined by 
E.O. 12866 and was therefore not submitted to the Office of Management 
and Budget for review.

B. Paperwork Reduction Act (PRA)

    This proposed action does not impose an information collection 
burden under the PRA because it does not contain any information 
collection activities.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action merely proposes to disapprove a SIP submission as not meeting 
the CAA.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. This action does not apply on any Indian 
reservation land, any other area where the EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction, or non-reservation areas of 
Indian country. Thus, Executive Order 13175 does not apply to this 
action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per

[[Page 9533]]

the definition of ``covered regulatory action'' in section 2-202 of the 
Executive Order. This action is not subject to Executive Order 13045 
because it merely proposes to disapprove a SIP submission as not 
meeting the CAA.

H. Executive Order 13211, Actions That Significantly Affect Energy 
Supply, Distribution or Use

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes the human health or environmental risk addressed 
by this action will not have potential disproportionately high and 
adverse human health or environmental effects on minority, low-income 
or indigenous populations. This action merely proposes to disapprove a 
SIP submission as not meeting the CAA.

K. CAA Section 307(b)(1)

    Section 307(b)(1) of the CAA governs judicial review of final 
actions by the EPA. This section provides, in part, that petitions for 
review must be filed in the D.C. Circuit: (i) When the agency action 
consists of ``nationally applicable regulations promulgated, or final 
actions taken, by the Administrator,'' or (ii) when such action is 
locally or regionally applicable, if ``such action is based on a 
determination of nationwide scope or effect and if in taking such 
action the Administrator finds and publishes that such action is based 
on such a determination.'' For locally or regionally applicable final 
actions, the CAA reserves to the EPA complete discretion whether to 
invoke the exception in (ii).\66\
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    \66\ In deciding whether to invoke the exception by making and 
publishing a finding that an action is based on a determination of 
nationwide scope or effect, the Administrator takes into account a 
number of policy considerations, including his judgment balancing 
the benefit of obtaining the D.C. Circuit's authoritative 
centralized review versus allowing development of the issue in other 
contexts and the best use of agency resources.
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    If the EPA takes final action on this proposed rulemaking, the 
Administrator intends to exercise the complete discretion afforded to 
him under the CAA to make and publish a finding that the final action 
(to the extent a court finds the action to be locally or regionally 
applicable) is based on a determination of ``nationwide scope or 
effect'' within the meaning of CAA section 307(b)(1). Through this 
rulemaking action (in conjunction with a series of related actions on 
other SIP submissions for the same CAA obligations), the EPA interprets 
and applies section 110(a)(2)(d)(i)(I) of the CAA for the 2015 ozone 
NAAQS based on a common core of nationwide policy judgments and 
technical analysis concerning the interstate transport of pollutants 
throughout the continental U.S. In particular, the EPA is applying here 
(and in other proposed actions related to the same obligations) the 
same, nationally consistent 4-step framework for assessing good 
neighbor obligations for the 2015 8-hour ozone NAAQS. The EPA relies on 
a single set of updated, 2016-base year photochemical grid modeling 
results of the year 2023 as the primary basis for its assessment of air 
quality conditions and contributions at Steps 1 and 2 of that 
framework. Further, the EPA proposes to determine and apply a set of 
nationally consistent policy judgments to apply the 4-step framework. 
The EPA has selected a nationally uniform analytic year (2023) for this 
analysis and is applying a nationally uniform approach to nonattainment 
and maintenance receptors and a nationally uniform approach to 
contribution threshold analysis.\67\
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    \67\ A finding of nationwide scope or effect is also appropriate 
for actions that cover states in multiple judicial circuits. In the 
report on the 1977 Amendments that revised section 307(b)(1) of the 
CAA, Congress noted that the Administrator's determination that the 
``nationwide scope or effect'' exception applies would be 
appropriate for any action that has a scope or effect beyond a 
single judicial circuit. See H.R. Rep. No. 95-294 at 323, 324, 
reprinted in 1977 U.S.C.C.A.N. 1402-03.
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    For these reasons, the Administrator intends, if this proposed 
action is finalized, to exercise the complete discretion afforded to 
him under the CAA to make and publish a finding that this action is 
based on one or more determinations of nationwide scope or effect for 
purposes of CAA section 307(b)(1).\68\
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    \68\ The EPA may take a consolidated, single final action on all 
of the proposed SIP disapproval actions with respect to obligations 
under CAA section 110(a)(2)(D)(i)(I) for the 2015 ozone NAAQS. 
Should EPA take a single final action on all such disapprovals, this 
action would be nationally applicable, and the EPA would also 
anticipate, in the alternative, making and publishing a finding that 
such final action is based on a determination of nationwide scope or 
effect.
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List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Ozone.

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

    Dated: February 7, 2022
Diana Esher,
Acting Regional Administrator, Region III.
[FR Doc. 2022-02952 Filed 2-18-22; 8:45 am]
BILLING CODE 6560-50-P


