[Federal Register Volume 87, Number 66 (Wednesday, April 6, 2022)]
[Proposed Rules]
[Pages 20036-20216]
[FR Doc No: 2022-04551]

Vol. 87

Wednesday,

No. 66

April 6, 2022

Part II

Environmental Protection Agency

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40 CFR Parts 52, 75, 78, et al.

Federal Implementation Plan Addressing Regional Ozone Transport for the
2015 Ozone National Ambient Air Quality Standard; Proposed Rule

Federal Register / Vol. 87, No. 66 / Wednesday, April 6, 2022 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52, 75, 78 and 97

[EPA-HQ-OAR-2021-0668; FRL 8670-01-OAR]
RIN 2060-AV51

Federal Implementation Plan Addressing Regional Ozone Transport
for the 2015 Ozone National Ambient Air Quality Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action proposes Federal Implementation Plan (FIP)
requirements to address twenty-six states' obligations to eliminate
significant contribution to nonattainment, or interference with
maintenance, of the 2015 ozone National Ambient Air Quality Standard
(NAAQS) in other states. The U.S. Environmental Protection Agency (EPA)
is proposing this action under the ``good neighbor'' or ``interstate
transport'' provision of the Clean Air Act (CAA or Act). The Agency
proposes establishing nitrogen oxides emissions budgets requiring
fossil fuel-fired power plants in 25 states to participate in an
allowance-based ozone season trading program beginning in 2023. The
Agency is also proposing to establish nitrogen oxides emissions
limitations applicable to certain other industrial stationary sources
in 23 states with an earliest possible compliance date of 2026. These
industrial source types are: Reciprocating internal combustion engines
in Pipeline Transportation of Natural Gas; kilns in Cement and Cement
Product Manufacturing; boilers and furnaces in Iron and Steel Mills and
Ferroalloy Manufacturing; furnaces in Glass and Glass Product
Manufacturing; and high-emitting equipment and large boilers in Basic
Chemical Manufacturing, Petroleum and Coal Products Manufacturing, and
Pulp, Paper, and Paperboard Mills.

DATES: Comments must be received on or before June 6, 2022.
    Public Hearing: The EPA will hold a virtual public hearing on April
21, 2022. Please refer to the SUPPLEMENTARY INFORMATION section for
additional information on the public hearing.
    Information Collection Request (ICR): Under the Paperwork Reduction
Act (PRA), comments on the information collection provisions are best
assured of consideration if the Office of Management and Budget (OMB)
receives a copy of your comments on or before May 6, 2022.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2021-0668; via the Federal eRulemaking Portal: https://www.regulations.gov/ (our preferred method). Follow the online
instructions for submitting comments.
    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. Hand deliveries and couriers may be
received by scheduled appointment only. For further information on EPA
Docket Center services and the current status, please visit us online
at https://www.epa.gov/dockets.
    The virtual public hearing will be held on April 21, 2022. The
virtual public hearing will convene at 10 a.m. Eastern Time (ET) and
will conclude at 7 p.m. ET. The EPA may close a session 15 minutes
after the last pre-registered speaker has testified if there are no
additional speakers. For information or questions about the public
hearing, please contact Ms. Holly DeJong at [email protected]. The
EPA will announce further details at https://www.epa.gov/csapr/csapr-2015-ozone-naaqs. Refer to the SUPPLEMENTARY INFORMATION section for
additional information.

FOR FURTHER INFORMATION CONTACT: Ms. Elizabeth Selbst, Air Quality
Policy Division, Office of Air Quality Planning and Standards (C539-
01), Environmental Protection Agency, 109 TW Alexander Drive, Research
Triangle Park, NC 27711; telephone number:<PHONE_NUMBER>; email
address: [email protected].

SUPPLEMENTARY INFORMATION:

Preamble Glossary of Terms and Abbreviations

    The following are abbreviations of terms used in the preamble.

2016v1 2016 Version 1 Emissions Modeling Platform
2016v2 2016 Version 2 Emissions Modeling Platform
4-Step Framework 4-Step Interstate Transport Framework
ACS American Community Survey
AEO Annual Energy Outlook
AQAT Air Quality Assessment Tool
AQMTSD Air Quality Modeling Technical Support Document
BACT Best Available Control Technology
BPT Benefit Per Ton
CAA or Act Clean Air Act
CAIR Clean Air Interstate Rule
CBI Confidential Business Information
CCR Coal Combustion Residual
CDC Centers for Disease Control and Prevention
CEMS Continuous Emissions Monitoring Systems
CES Clean Energy Standards
CHP Combined Heat and Power
CMDB Control Measures Database
CMV Commercial Marine Vehicle
CoST Control Strategy Tool
CPT Cost Per Ton
CSAPR Cross-State Air Pollution Rule
EGU Electric Generating Unit
EIA U.S. Energy Information Agency
EISA Energy Independence and Security Act
ELG Effluent Limitation Guidelines
E.O. Executive Order
EPA or the Agency United States Environmental Protection Agency
FFS Finding of Failure To Submit
FIP Federal Implementation Plan
GIS Geographic Information System
HDGHG Greenhouse Gas Emissions and Fuel Efficiency Standards for
Medium- and Heavy-Duty Engines and Vehicles
HEDD High Electricity Demand Days
ICI Industrial, Commercial, and Institutional
I/M Inspection and Maintenance
IPM Integrated Planning Model
LNB Low-NOX Burners
MJO Multi-Jurisdictional Organization
MOVES Motor Vehicle Emission Simulator
MSAT2 Mobile Source Air Toxics Rule
MWC Municipal Waste Combustor
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NEEDS National Electric Energy Data System
NEI National Emissions Inventory
NESHAP National Emissions Standards for Hazardous Air Pollutants
No SISNOSE No Significant Economic Impact on a Substantial Number of
Small Entities
Non-EGU Non-Electric Generating Unit
NOX Nitrogen Oxides
NSPS New Source Performance Standard
NREL National Renewable Energy Lab
NTTAA National Technology Transfer and Advancement Act
OFA Over-Fire Air
OMB United States Office of Management and Budget
OSAT/APCA Ozone Source Apportionment Technology/Anthropogenic
Precursor Culpability Analysis
OTC Ozone Transport Commission
OTR Ozone Transport Region
OTSA Oklahoma Tribal Statistical Area
PEMS Predictive Emissions Monitoring Systems

PM2.5 Fine Particulate Matter
ppb parts per billion
ppm parts per million
ppmvd parts per million by volume, dry
PRA Paperwork Reduction Act
RACT Reasonably Available Control Technology
RFA Regulatory Flexibility Act
RICE Reciprocating Internal Combustion Engines
ROP Rate of Progress
RPS Renewable Portfolio Standards
RRF Relative Response Factor
SAFE Safer Affordable Fuel-Efficient Vehicles Rule
SAFETEA Safe, Accountable, Flexible, Efficient, Transportation
Equity Act
SCR Selective Catalytic Reduction
SIP State Implementation Plan
SMOKE Sparse Matrix Operator Kernel Emissions
SNCR Selective Non-Catalytic Reduction
SO2 Sulfur Dioxide
tpd ton per day
TSD Technical Support Document
UMRA Unfunded Mandates Reform Act
VMT Vehicle Miles Traveled
VOCs Volatile Organic Compounds
WRAP Western Regional Air Partnership
WRF Weather Research and Forecasting

Table of Contents

I. Executive Summary
    A. Purpose of Regulatory Action
    1. Emissions Limitations for EGUs Established by the Proposed
Rule
    2. Emissions Limitations for Non-EGU Stationary Point Sources
Established by the Proposed Rule
    3. Proposed Error Correction for Previously Approved 2015 Ozone
Transport SIP
    4. Request for Comment on All Aspects of the Proposal
    B. Summary of the Major Provisions of the Regulatory Action
    C. Benefits and Costs
II. Public Participation
    A. Written Comments
    B. Submitting Confidential Business Information
    C. Participation in Virtual Public Hearing
III. General Information
    A. Does this action apply to me?
    B. What action is the Agency taking?
    C. What is the Agency's legal authority for taking this action?
    1. Statutory Authority
    D. What actions has EPA previously issued to address regional
ozone transport?
IV. Air Quality Issues Addressed and Overall Approach for the
Proposed Rule
    A. The Interstate Ozone Transport Air Quality Challenge
    1. Nature of Ozone and the Ozone NAAQS
    2. Ozone Transport
    3. Health and Environmental Effects
    B. Proposed Rule Approach
    1. The 4-Step Interstate Transport Framework
    a. Step 1 Approach
    b. Step 2 Approach
    c. Step 3 Approach
    d. Step 4 Approach
    2. FIP Authority for Each State Covered by the Proposed Rule
    C. Other CAA Authorities for This Action
    1. Correction of EPA's Determination Regarding Delaware's SIP
Submission and Its Impact on EPA's FIP Authority for Delaware
    2. Application of Rule in Indian Country and Necessary or
Appropriate Finding
    a. Indian Country Subject to State Implementation Planning
Authority
V. Analyzing Downwind Air Quality Problems and Contributions From
Upwind States
    A. Selection of Analytic Years for Evaluating Ozone Transport
Contributions to Downwind Air Quality Problems
    B. Overview of Air Quality Modeling Platform
    C. Emissions Inventories
    1. Foundation Emissions Inventory Data Sets
    2. Development of Emissions Inventories for EGUs
    3. Development of Emissions Inventories for Non-EGU Point
Sources
    4. Development of Emissions Inventories for Onroad Mobile
Sources
    5. Development of Emissions Inventories for Commercial Marine
Vessels
    6. Development of Emissions Inventories for Other Nonroad Mobile
Sources
    7. Development of Emissions Inventories for Nonpoint Sources
    D. Air Quality Modeling To Identify Nonattainment and
Maintenance Receptors
    E. Pollutant Transport From Upwind States
    1. Air Quality Modeling To Quantify Upwind State Contributions
    2. Application of Contribution Screening Threshold
    a. States That Contribute at or Above the Screening Threshold
    F. Treatment of Certain Receptors in California and Implications
for Oregon's Good Neighbor Obligations for 2015 Ozone NAAQS
VI. Quantifying Upwind-State NOX Emissions Reduction
Potential To Reduce Interstate Ozone Transport for the 2015 Ozone
NAAQS
    A. The Multi-Factor Test for Determining Significant
Contribution
    B. Identifying Control Stringency Levels
    1. EGU NOX Mitigation Strategies
    a. Optimizing Existing SCRs
    b. Installing State-of-the-Art NOX Combustion
Controls
    c. Optimizing Already Operating SNCRs or Turning on Idled
Existing SNCRs
    d. Installing New SNCRs
    e. Installing New SCRs
    f. Generation Shifting
    2. Non-EGU NOX Mitigation Strategies
    a. Determining Non-EGU NOX Reduction Potential
    3. Other Stationary Sources NOX Mitigation Strategies
    a. Units Less Than or Equal to 25 MW
    b. Municipal Solid Waste Units
    c. Cogeneration Units
    4. Mobile Source NOX Mitigation Strategies
    C. Control Stringencies Represented by Cost Threshold ($ per
Ton) and Corresponding Emissions Reductions
    1. EGU Emissions Reduction Potential by Cost Threshold
    2. Non-EGU Emissions Reduction Potential--Cost Threshold Up to
$7,500/Ton
    D. Assessing Cost, EGU and Non-EGU NOX Reductions,
and Air Quality
    1. EGU Assessment
    2. Non-EGU Assessment
    a. Request for Comment on Non-EGU Control Strategies and
Measures
    3. Combined EGU and Non-EGU Assessment
    4. Over-Control Analysis
VII. Implementation of Emissions Reductions
    A. NOX Reduction Implementation Schedule
    1. 2023-2025: EGU NOX Reductions Beginning in 2023
    2. 2026 and Later Years: EGU and Non-EGU EGU NOX
Reductions Beginning in 2026
    a. EGU Schedule for 2026 and Later Years
    b. Non-EGU Schedule for 2026 and Later Years
    B. Regulatory Requirements for EGUs
    1. Trading Program Background and Overview of Proposed Revisions
    a. Current CSAPR Trading Program Design Elements and Identified
Concerns
    b. Enhancements To Maintain Selected Control Stringency Over
Time
    i. Revised Emissions Budget-Setting Process
    ii. Allowance Bank Recalibration
    c. Enhancements To Improve Emissions Performance at Individual
Units
    i. Unit-Specific Backstop Daily Emissions Rates
    ii. Unit-Specific Emissions Limitations Contingent on Assurance
Level Exceedances
    2. Expansion of Geographic Scope
    3. Applicability and Tentative Identification of Newly Affected
Units
    4. New and Revised State Emissions Budgets
    a. Methodology for Determining Preset State Emissions Budgets
for the 2023 and 2024 Control Periods
    b. Methodology for Determining Dynamic State Emissions Budgets
for Control Periods in 2025 and Beyond
    c. Proposed and Illustrative State Emissions Budgets
    5. Variability Limits and Assurance Levels
    6. Annual Recalibration of Allowance Bank
    7. Unit-Specific Backstop Daily Emissions Rates
    8. Unit-Specific Emissions Limitations Contingent on Assurance
Level Exceedances
    9. Unit-Level Allowance Allocation and Recordation Procedures
    a. Set-Asides of Portions of State Emissions Budgets for New
Units
    b. Allocations to Existing Units, Including Units That Cease
Operation
    c. Allocations From Portions of State Emissions Budgets Set
Aside for New Units
    d. Incorrectly Allocated Allowances
    10. Other Trading Program Provisions
    a. Designated Representative Requirements
    b. Monitoring and Reporting Requirements
    11. Transitional Provisions
    a. Prorating Emissions Budgets, Assurance Levels, and Unit-Level
Allowance

Allocations in the Event of an Effective Date After May 1, 2023
    b. Creation of Additional Group 3 Allowance Bank for 2023
Control Period
    c. Recall of Group 2 Allowances for Control Periods After 2022
    12. Conforming Revisions to Other Regulations
    C. Regulatory Requirements for Non-EGUs
    1. Pipeline Transportation of Natural Gas
    2. Cement and Concrete Product Manufacturing
    3. Iron and Steel Mills and Ferroalloy Manufacturing
    4. Glass and Glass Product Manufacturing
    5. Boilers From Basic Chemical Manufacturing, Petroleum and Coal
Products Manufacturing, and Pulp, Paper, and Paperboard Mills
    a. Coal-Fired Industrial Boilers
    b. Oil-Fired Industrial Boilers
    c. Gas-Fired Industrial Boilers
    D. Submitting a SIP
    1. SIP Option To Modify Allocations for 2024 Under EGU Trading
Program
    2. SIP Option To Modify Allocations for 2025 and Beyond Under
EGU Trading Program
    3. SIP Option To Replace the Federal EGU Trading Program With an
Integrated State EGU Trading Program
    4. SIP Revisions That Do Not Use the New Trading Program
    5. SIP Revision Requirements for Non-EGU Emissions Limits
    E. Title V Permitting
    F. Relationship to Other Emissions Trading and Ozone Transport
Programs
    1. NOX SIP Call
    2. Acid Rain Program
    3. Other Current Emissions Trading Programs
VIII. Environmental Justice Considerations, Implications, and
Stakeholder Outreach
    A. Introduction
    B. Analytical Considerations
    C. Outreach and Engagement
IX. Costs, Benefits, and Other Impacts of the Proposed Rule
X. Summary of Proposed Changes to the Regulatory Text for the
Federal Implementation Plans and Trading Programs for EGUs
    A. Amendments to FIP Provisions in 40 CFR Part 52
    B. Amendments to Group 3 Trading Program and Related Regulations
    C. Transitional Provisions
    D. Clarifications and Conforming Revisions
XI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Determinations Under CAA Section 307(b)(1) and (d)

I. Executive Summary

    This proposed rule would resolve the interstate transport
obligations of 26 states under CAA section 110(a)(2)(D)(i)(I), referred
to as the ``good neighbor provision'' or the ``interstate transport
provision'' of the Act, for the 2015 ozone NAAQS. On October 1, 2015,
the EPA revised the primary and secondary 8-hour standards for ozone to
70 parts per billion (ppb).\1\ States were required to provide ozone
infrastructure State Implementation Plan (SIP) submissions to fulfill
interstate transport obligations for the 2015 ozone NAAQS by October 1,
2018.
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    \1\ See 80 FR 65291 (October 26, 2015).
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    The EPA proposes to make a finding that interstate transport of
ozone precursor emissions from 26 upwind states (Alabama, Arkansas,
California, Delaware, Illinois, Indiana, Kentucky, Louisiana, Maryland,
Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New
York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Utah, Virginia,
West Virginia, Wisconsin, and Wyoming) is significantly contributing to
downwind nonattainment or interfering with maintenance of the 2015
ozone NAAQS in other states, based on projected nitrogen oxides
(NOX) emissions in the 2023 ozone season. The EPA is
proposing to issue FIP requirements to eliminate interstate transport
of ozone precursors from these 26 states that significantly contributes
to nonattainment or interferes with maintenance of the NAAQS in other
states.
    The EPA is proposing FIPs for 23 states for which the Agency has
not approved an ozone transport SIP that was submitted for the 2015
ozone NAAQS: Alabama, Arkansas, California, Illinois, Indiana,
Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi,
Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, Tennessee,
Texas, Utah, West Virginia, Wisconsin, and Wyoming. In this proposed
rule, the EPA is proposing to issue FIPs for two states--Pennsylvania
and Virginia--for which the EPA issued a Finding of Failure to Submit
for 2015 ozone transport SIPs with an effective date of January 6,
2020. Under CAA section 301(d)(4), the EPA proposes to extend FIP
requirements to apply in Indian country located within the upwind
geography of the proposed rule, including Indian reservation lands and
other areas of Indian country over which the EPA or a tribe has
demonstrated that a tribe has jurisdiction.\2\ The EPA is also
proposing a FIP for Delaware and an error correction for the Agency's
May 1, 2020, approval at 85 FR 25307 of the interstate transport
elements for Delaware's October 11, 2018, and December 26, 2019, ozone
infrastructure SIP submissions.
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    \2\ In general, specific tribal names or reservations are not
identified separately in this proposal except as needed. See Section
IV.C.2 of this notice for further discussion.
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    In this proposed rule, the EPA proposes to establish new ozone
season NOX emissions budgets beginning in 2023 for Electric
Generating Unit (EGU) sources. The EPA is also proposing to establish
emissions limitations beginning in 2026 for certain other industrial
stationary sources (referred to generally as ``non-Electric Generating
Units'' (non-EGUs)). Taken together, these strategies will fully
eliminate the covered states' significant contribution to downwind
ozone air quality problems in other states.
    The EPA proposes to implement the necessary emissions reductions as
follows. The proposed FIP requirements establish ozone season
NOX emissions budgets for EGUs in 25 states (Alabama,
Arkansas, Delaware, Illinois, Indiana, Kentucky, Louisiana, Maryland,
Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New
York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Utah, Virginia,
West Virginia, Wisconsin, and Wyoming) and require EGUs in these states
to participate in a revised version of the Cross-State Air Pollution
Rule (CSAPR) NOX Ozone Season Group 3 Trading Program that
was previously established in the Revised CSAPR Update.\3\ The EPA
proposes to amend existing FIPs for 12 states currently participating
in the CSAPR NOX Ozone Season Group 3 Trading Program
(Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, New
Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia) to
replace their existing emissions budgets established in the Revised
CSAPR Update (with respect to the 2008 ozone NAAQS) with new

emissions budgets. For eight states currently covered by the CSAPR
NOX Ozone Season Group 2 Trading Program under SIPs or FIPs,
the EPA is proposing to issue new FIPs for two states (Alabama and
Missouri) and amend existing FIPs for six states (Arkansas,
Mississippi, Oklahoma, Tennessee, Texas, and Wisconsin) to transition
EGU sources in these states from the Group 2 program to the revised
Group 3 trading program, beginning with the 2023 ozone season. EPA
proposes to issue new FIPs for five states not currently covered by any
CSAPR NOX ozone season trading program: Delaware, Minnesota,
Nevada, Utah, and Wyoming.
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    \3\ As explained in Section VI.C.1 of this notice, EPA proposes
finding that EGU sources within the State of California are
sufficiently controlled such that no further emissions reductions
are needed from them to eliminate significant contribution to
downwind states.
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    Under this proposed rulemaking, emissions reductions in the
selected control stringency would be achieved as soon as they are
available, some of which are scheduled to occur by the 2023 ozone
season and prior to the August 3, 2024, attainment date for areas
classified as Moderate nonattainment for the 2015 ozone NAAQS, and the
rest of which occur as soon as possible thereafter through the 2026
ozone season, prior to the August 3, 2027, attainment date for areas
classified as Serious nonattainment for the 2015 ozone NAAQS. As
discussed in Section VII.A.2 of this notice, the EPA proposes to find
that the 2026 ozone season is as expeditious as practicable to
implement substantial emissions reductions from potential new post-
combustion control installations at EGUs as well as from installation
of new pollution controls at non-EGUs.
    These EGU emissions reductions are scheduled to begin in the 2026
ozone season based on the feasibility of control installation for EGUs
in 22 states that remain linked to downwind nonattainment and
maintenance receptors in that year. These 22 states are: Arkansas,
Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Minnesota,
Mississippi, Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma,
Pennsylvania, Texas, Utah, Virginia, West Virginia, Wisconsin, and
Wyoming. The additional emissions reductions required for these states
are based primarily on the potential retrofit of additional post-
combustion controls for NOX on most coal steam EGUs and a
portion of oil/gas steam EGUs that are currently lacking such controls.
    In this proposed rule, the EPA introduces additional features to
the allowance-based trading program approach for EGUs, including
dynamic adjustments of the emissions budgets over time and backstop
daily emissions rate limits for most coal-fired units, that will help
maintain control stringency over time and improve emissions performance
at individual units, providing further assurance that existing
pollution controls will be operated during the ozone season and that
the emission reductions necessary to meet good neighbor requirements
will be achieved.
    The EPA proposes to find that NOX emissions from non-EGU
sources are significantly contributing to nonattainment or interfering
with maintenance of the 2015 ozone NAAQS and that cost-effective
controls for NOX emissions reductions are available in
certain industrial source categories that would result in meaningful
air quality improvements in downwind receptors. The EPA proposes to
require emissions limitations beginning in 2026 for non-EGUs located
within 23 states: Arkansas, California, Illinois, Indiana, Kentucky,
Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri,
Nevada, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Texas,
Utah, Virginia, West Virginia, Wisconsin, and Wyoming. The proposed
rule establishes NOX emissions limitations during the ozone
season for the following unit types for sources in non-EGU industries:
Reciprocating internal combustion in Pipeline Transportation of Natural
Gas sources; kilns in Cement and Cement Product Manufacturing sources;
boilers and furnaces in Iron and Steel Mills and Ferroalloy
Manufacturing sources; furnaces in Glass and Glass Product
Manufacturing sources; and high-emitting equipment and large boilers in
Basic Chemical Manufacturing, Petroleum and Coal Products
Manufacturing, and Pulp, Paper, and Paperboard Mills.

A. Purpose of the Regulatory Action

    The purpose of this rulemaking is to protect public health and the
environment by reducing interstate transport of certain air pollutants
that significantly contribute to nonattainment, or interfere with
maintenance, of the 2015 ozone NAAQS in other states. Ground-level
ozone has detrimental effects on human health as well as vegetation and
ecosystems. Acute and chronic exposure to ozone in humans is associated
with premature mortality and a number of morbidity effects, such as
asthma exacerbation. Ozone exposure can also negatively impact
ecosystems by limiting tree growth, causing foliar injury, and changing
ecosystem community composition. Section IV of this proposed rule
provides additional evidence of the harmful effects of ozone exposure
on human health and the environment. Studies have established that
ozone air pollution can be transported over hundreds of miles, with
elevated ground-level ozone concentrations occurring in rural and
metropolitan areas.4 5 Assessments of ozone control
approaches have concluded that control strategies targeting reduction
of NOX emissions are an effective method to reduce regional-
scale ozone transport.\6\
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    \4\ Bergin, M.S. et al. (2007) Regional air quality: Local and
interstate impacts of NOX and SO2 emissions on
ozone and fine particulate matter in the eastern United States.
Environmental Sci & Tech. 41: 4677-4689.
    \5\ Liao, K. et al. (2013) Impacts of interstate transport of
pollutants on high ozone events over the Mid-Atlantic United States.
Atmospheric Environment 84, 100-112.
    \6\ See 82 FR 51238, 51248 (November 3, 2017) [citing 76 FR
48208, 48222 (August 8, 2011)] and 63 FR 57381 (October 27, 1998).
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    CAA section 110(a)(2)(D)(i)(I) requires states to prohibit
emissions that will contribute significantly to nonattainment or
interfere with maintenance in any other state with respect to any
primary or secondary NAAQS.\7\ States fulfill their primary
responsibility to address interstate transport emissions under the good
neighbor provision by submitting SIPs containing enforceable emission
limitations and other control measures, means, or techniques required
to address the interstate transport provision. Within 3 years of the
EPA promulgating a new or revised NAAQS, states are required to provide
infrastructure SIP submittals, including good neighbor SIPs. See CAA
section 110(a)(1) and (2). When states do not submit approvable
interstate transport SIPs or fail to submit interstate transport SIPs
by the statutory deadline, the CAA requires the EPA to issue FIPs to
ensure that states eliminate their significant contribution to downwind
air quality problems under the good neighbor provision. See generally
CAA section 110(k) and 110(c). As such, in this proposed rule, the EPA
is proposing requirements to fully address good neighbor obligations
for these states for the 2015 ozone NAAQS under its authority to
promulgate FIPs under CAA section 110(c).
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    \7\ 42 U.S.C. 7410(a)(2)(D)(i)(I).
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    It is appropriate to issue this proposal at this time for at least
three reasons. First, this proposal will ensure that necessary
emissions reductions to eliminate significant contribution are achieved
as expeditiously as practicable. The EPA's anticipated timing will
provide for all possible emissions reductions to go into effect

beginning in the 2023 ozone season, which is aligned with the next
upcoming attainment date of August 3, 2024, for areas classified as
Moderate nonattainment under the 2015 ozone standard. Additional
emissions reductions that the EPA finds not possible to implement by
that attainment date are proposed to take effect as expeditiously as
practicable, with the full suite of emissions reductions taking effect
by the 2026 ozone season, which is aligned with the August 3, 2027,
attainment date for areas classified as Serious nonattainment under the
2015 ozone NAAQS. As explained in sections V.A, VI, and VII.A of this
proposed rule, these proposed timeframes for eliminating significant
contribution are consistent with the provisions of title I of the CAA.
Second, this proposal will provide states with as much information as
the EPA can supply at this time to support their ability to submit SIP
revisions to achieve the emissions reductions the EPA believes
necessary to eliminate significant contribution. Third, for all of the
states included in this proposed rule, the EPA's modeling and analysis
indicate that additional emissions reductions beyond those which are
provided in any state's 2015 ozone transport SIP are necessary to
eliminate significant contribution.
    The EPA anticipates that the states covered in this proposed FIP
rulemaking may not have adequate provisions in their SIPs to address
their interstate transport obligations for the 2015 ozone NAAQS. As
discussed in Section IV.B.2 of this proposed rule, the EPA has, for
certain states, made findings that the state failed to submit a
complete good neighbor SIP revision for the 2015 ozone NAAQS. For
certain other states, the EPA has proposed, but has not finalized,
actions disapproving good neighbor SIP revisions. And for other states,
the EPA has not yet proposed action on their good neighbor SIP
submittals, but these submittals are currently under review, and EPA
intends to act on these submittals in the coming months. The EPA will
not finalize this proposed FIP action for any state for which it has
not taken final action either disapproving that state's good neighbor
SIP submittal or finding that the state failed to submit a complete
SIP.
    The EPA conducted air quality modeling for future analytic years to
identify (1) the downwind areas that are expected to have trouble
attaining or maintaining the 2015 ozone NAAQS in the future and (2) the
contribution of ozone transport from upwind states to the downwind air
quality problems. Section V of this proposed rule provides a full
description of the results of EPA's air quality modeling and relevant
analyses for the proposed rulemaking. Based on EPA's air quality
analysis, a total of 27 upwind states are linked above the 1 percent of
the NAAQS threshold to downwind air quality problems in other states.
The EPA had previously approved 2015 ozone transport SIPs submitted by
two of these states--Oregon and Delaware--and proposes in this proposed
rule to issue an error correction for its prior approval of Delaware's
2015 ozone transport SIP (see Section IV.C.1 of this notice for
additional information on the proposed error correction). The EPA is
not proposing any change to its prior approval of Oregon's 2015 ozone
transport SIP, a determination which is further described in Section
V.F of this proposed rule.
    In this proposed rule, the EPA is proposing to issue FIP
requirements for 26 states, which include emissions reductions for EGU
sources within the borders of 25 states (described in Section VII.B of
this proposed rule) and include emissions reductions for non-EGU
sources within the borders of 23 states (described in Section VII.C in
this proposed rule). Based on EPA's assessment of remaining air quality
issues and additional emissions control strategies, the EPA further
proposes to find that the EGU and non-EGU NOX emissions
reductions required in the proposed rule would fully eliminate these
states' significant contributions to downwind air quality problems for
the 2015 ozone NAAQS. By eliminating significant contribution from
these upwind states, this rule, if finalized as proposed, will make
substantial and meaningful improvements in air quality by reducing
ozone levels at the identified downwind receptors as well as many other
areas of the country.
1. Emissions Limitations for EGUs Established by the Proposed Rule
    In this proposed rule, the EPA proposes to issue FIP requirements
that include new NOX ozone season emissions budgets for EGU
sources within the borders of the 25 states listed in Table I.A-1, with
implementation of these emissions budgets beginning in the 2023 ozone
season. The EPA proposes to find that these emissions reductions are
necessary to address upwind states' interstate transport obligations
for the 2015 ozone NAAQS.

    Table I.A-1--Proposed List of 25 Covered States for EGU Emissions
               Reductions for the 2015 8-Hour Ozone NAAQS
------------------------------------------------------------------------
                                  State
-------------------------------------------------------------------------
Alabama
Arkansas
Delaware
Illinois
Indiana
Kentucky
Louisiana
Maryland
Michigan
Minnesota
Mississippi
Missouri
Nevada
New Jersey
New York
Ohio
Oklahoma
Pennsylvania
Tennessee
Texas
Utah
Virginia
West Virginia
Wisconsin
Wyoming
------------------------------------------------------------------------

    The EPA proposes to expand the CSAPR NOX Ozone Season
Group 3 Trading Program beginning in the 2023 ozone season.
Specifically, the FIPs would require power plants within the borders of
the 25 states listed in Table I.A-1 to participate in a revised version
of the CSAPR NOX Ozone Season Group 3 Trading Program
created by the Revised CSAPR Update. Affected EGUs within the borders
of twelve states currently participating in the Group 3 Trading Program
under FIPs or SIPs would remain in the program, with revised provisions
beginning in the 2023 ozone season, under this proposed rule: Illinois,
Indiana, Kentucky, Louisiana, Maryland, Michigan, New Jersey, New York,
Ohio, Pennsylvania, Virginia, and West Virginia. The FIPs would also
require affected EGUs within the borders of eight states currently
covered by the CSAPR NOX Ozone Season Group 2 Trading
Program (the ``Group 2 trading program'') under existing FIPs or
existing SIPs to transition from the Group 2 program to the revised
Group 3 trading program beginning with the 2023 control period:
(Alabama, Arkansas, Mississippi, Missouri, Oklahoma, Tennessee, Texas,
and Wisconsin).\8\ Finally, the EPA is

proposing to issue new FIPs for EGUs within the borders of five states
not currently covered by any CSAPR trading program for seasonal
NOX emissions: Delaware, Minnesota, Nevada, Utah, and
Wyoming. If the proposed FIP is finalized, sources in these states
would enter the Group 3 trading program in the 2023 control period
following the effective date of the final rule.\9\ In all cases, if the
state submits and the EPA approves a SIP revision that would fully
achieve the emissions reductions needed to meet the state's good
neighbor obligations with respect to the 2015 ozone NAAQS before a
final rule is promulgated in this rulemaking, the proposed FIP
requirements summarized above would not be finalized. Refer to Section
VII.B of this proposed rule for details on EGU regulatory requirements.
---------------------------------------------------------------------------

    \8\ Six of these eight states (Arkansas, Mississippi, Oklahoma,
Tennessee, Texas, and Wisconsin) currently participate in the
federal Group 2 trading program pursuant to the FIPs finalized in
the CSAPR Update, so the FIPs proposed in this rulemaking would
amend the existing FIPs for these states. The other two states
(Alabama and Missouri) have already replaced the FIPs finalized in
the CSAPR Update with approved SIP revisions that require their EGUs
to participate in state Group 2 trading programs integrated with the
federal Group 2 trading program, so the FIPs proposed in this action
would constitute new FIPs for these states, and the EPA would cease
implementation of the state Group 2 trading programs included in the
two states' SIPs.
    \9\ Two states, Kansas and Iowa, will remain in the Group 2
Trading Program.
---------------------------------------------------------------------------

2. Emissions Limitations for Non-EGU Stationary Point Sources
Established by the Proposed Rule
    In this proposed rule, the EPA proposes to issue FIP requirements
that include new NOX emissions limitations for non-Electric
Generating Unit (non-EGU) sources in 23 states, with earliest possible
compliance dates for these emissions limitations beginning in 2026. The
EPA proposes to require emissions reductions from non-EGU sources to
address interstate transport obligations for the 2015 ozone NAAQS for
the 23 states listed in Table I.A-2.

  Table I.A-2--Proposed List of 23 Covered States for Non-EGU Emissions
               Reductions for the 2015 8-Hour Ozone NAAQS
------------------------------------------------------------------------
                                  State
-------------------------------------------------------------------------
Arkansas
California
Illinois
Indiana
Kentucky
Louisiana
Maryland
Michigan
Minnesota
Mississippi
Missouri
Nevada
New Jersey
New York
Ohio
Oklahoma
Pennsylvania
Texas
Utah
Virginia
West Virginia
Wisconsin
Wyoming
------------------------------------------------------------------------

    The EPA is proposing to require emissions limitations for the
following unit types in non-EGU industries: Reciprocating internal
combustion engines in Pipeline Transportation of Natural Gas sources;
kilns in Cement and Cement Product Manufacturing sources; boilers and
furnaces in Iron and Steel Mills and Ferroalloy Manufacturing sources;
furnaces in Glass and Glass Product Manufacturing sources; and high-
emitting equipment and large boilers in Basic Chemical Manufacturing,
Petroleum and Coal Products Manufacturing, and Pulp, Paper, and
Paperboard Mills. Refer to Table III.A-1 for a list of North American
Industry Classification System (NAICS) codes for each entity included
for regulation under this proposed rule.
3. Proposed Error Correction for Previously Approved 2015 Ozone
Transport SIP
    The EPA proposes to make an error correction under CAA section
110(k)(6) of its May 1, 2020, approval at 85 FR 25307 of the interstate
transport elements for Delaware's October 11, 2018, and December 26,
2019, ozone infrastructure SIP submissions as satisfying the
requirements of CAA section 110(a)(2)(D)(i)(I) for the 2015 ozone
NAAQS. The EPA proposes to determine that the basis for the prior SIP
approval is invalidated by the Agency's more recent technical
evaluation of air quality modeling performed in support of the proposed
rule,\10\ and that Delaware has unresolved interstate transport
obligations for the 2015 ozone NAAQS. In this proposed rule, the EPA is
also exercising its authority to propose to issue a FIP for Delaware in
light of these unresolved interstate transport obligations.
---------------------------------------------------------------------------

    \10\ See the Air Quality Modeling Technical Support Document
(AQM TSD) in the docket for this proposed rule.
---------------------------------------------------------------------------

4. Request for Comment on All Aspects of the Proposal
    Throughout this proposed rule, unless noted otherwise, the EPA is
requesting comments on all aspects of the proposal to enable the Agency
to develop a final rule that, consistent with our responsibilities
under section 110 of the CAA, eliminates air pollution that
significantly contributes to nonattainment or interference with
maintenance of the 2015 ozone NAAQS. This proposed rule adheres closely
to the legal and analytical framework that the EPA has applied in the
past in implementing the good neighbor provision of the CAA, as well as
the ample case law reviewing that framework. At the same time, in this
proposal, the EPA is applying lessons learned from the performance of
regulatory programs established by previous ozone transport
rulemakings, as well as updating the Agency's application of the 4-step
interstate transport framework with recent information on the nature of
ozone transport and emissions reductions opportunities in order to
eliminate significant contribution for the more stringent 2015 ozone
NAAQS under the good neighbor provision. The EPA invites comments and
information to support its efforts to improve the regulation of
interstate ozone transport under the good neighbor provision and to
fulfill our mission to protect human health and the environment. The
EPA will carefully consider information provided in response to this
request and will respond to comments submitted through the regulatory
docket in the final rule.

B. Summary of the Major Provisions of the Regulatory Action

    The EPA is applying the 4-step interstate transport framework
developed in CSAPR, the CSAPR Update, the Revised CSAPR Update, and
other previous ozone transport rules to propose to further limit
NOX emissions from EGU sources within the borders of 25
states during the ozone season (May 1 through September 30) and to
limit ozone season NOX emissions from non-EGU sources in 23
states to reduce interstate ozone transport under the authority
provided in CAA section 110(a)(2)(D)(i)(I). The 4-step interstate
transport framework provides a stepwise method for the EPA to propose
rule provisions that are required to address the requirements of the
good neighbor provision for the 2015 ozone NAAQS: (1) Identifying
downwind receptors that are expected to have problems attaining or

maintaining the NAAQS; (2) determining which upwind states contribute
to these identified problems in amounts sufficient to ``link'' them to
the downwind air quality problems (i.e., in this proposed rule, a
contribution threshold of 1 percent of the NAAQS); (3) for states
linked to downwind air quality problems, identifying upwind emissions
that significantly contribute to downwind nonattainment or interfere
with downwind maintenance of the NAAQS; and (4) for states that are
found to have emissions that significantly contribute to nonattainment
or interfere with maintenance of the NAAQS in downwind areas,
implementing the necessary emissions reductions through enforceable
measures. In this proposed rule, the EPA applies the 4-step framework
to evaluate upwind states' obligations to reduce interstate transport
of ozone precursor emissions for the 2015 ozone NAAQS. The remainder of
this section provides a general overview of the EPA's application of
the 4-step framework as it applies to major provisions of the proposed
rule; additional details regarding EPA's proposed rule approach are
found in Section IV of this proposed rule.
    In order to apply the first step of the 4-step framework to the
2015 ozone NAAQS, the EPA performed air quality modeling to project
ozone concentrations at air quality monitoring sites in 2023, 2026, and
2032.\11\ The EPA evaluated projected ozone concentrations for the 2023
analytic year at individual monitoring sites and considered current
ozone monitoring data at these sites to identify receptors that are
anticipated to have problems attaining or maintaining the 2015 ozone
NAAQS. This analysis was then repeated using projected ozone
concentrations for 2026 and 2032.
---------------------------------------------------------------------------

    \11\ These 3 analytic years are the last full ozone seasons
before, and thus align with, upcoming attainment dates for the 2015
ozone NAAQS: August 3, 2024, for areas classified as Moderate
nonattainment, August 3, 2027, for areas classified as Serious
nonattainment, and August 3, 2033, for areas classified as Severe.
See 83 FR 25776.
---------------------------------------------------------------------------

    To apply the second step of the framework, the EPA used air quality
modeling to quantify the contributions from upwind states to ozone
concentrations in 2023 and 2026 at downwind receptors.\12\ Once
quantified, EPA then evaluated these contributions relative to a
screening threshold of 1 percent of the NAAQS (i.e., 0.70 ppb).\13\
States with contributions that equaled or exceeded 1 percent of the
NAAQS were identified as warranting further analysis at Step 3 of the
four-step framework to determine if the upwind state significantly
contributes to nonattainment or interference with maintenance in a
downwind state. States with contributions below 1 percent of the NAAQS
were considered not to significantly contribute to nonattainment or
interfere with maintenance of the NAAQS in downwind states. Based on
EPA's most recent air quality modeling and contribution analysis using
2023 as the analytic year, the EPA proposes to find that the following
27 states have contributions that equal or exceed 1 percent of the 2015
ozone NAAQS, and, thereby, warrant further analysis of significant
contribution to nonattainment or interference with maintenance of the
NAAQS: Alabama, Arkansas, California, Delaware, Illinois, Indiana,
Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi,
Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, Oregon,
Pennsylvania, Tennessee, Texas, Utah, Virginia, West Virginia,
Wisconsin, and Wyoming. Further evaluation of the locations in
California to which Oregon was linked at Step 2 leads the EPA to
conclude downwind areas represented by these monitoring sites should
not be considered interstate ozone transport receptors. Therefore, the
EPA is not proposing any further emissions reductions from the state of
Oregon because there is no significant contribution required to be
eliminated under the interstate transport provision, as described in
Section V.F of this proposed rule.
---------------------------------------------------------------------------

    \12\ The EPA did not perform contribution modeling for 2032
since contribution data for this year were not needed to identify
upwind states to be analyzed in Step 3.
    \13\ See Section V of this proposed rule for explanation of
EPA's use of the 1 percent of the NAAQS threshold in the Step 2
analysis.
---------------------------------------------------------------------------

    Based on the air quality analysis presented in Section V of this
proposed rule, the EPA proposes to find that in the absence of
additional emissions reductions in those states the majority of the
states that the EPA is proposing to participate in the Ozone Season
Group 3 Trading Program will continue to contribute above the 1 percent
of the NAAQS threshold to at least one receptor whose nonattainment and
maintenance concerns persist through the 2026 ozone season, with the
exception of Alabama, Delaware, and Tennessee. As a result, EPA's
evaluation of emissions reduction potential at Step 3 for Alabama,
Delaware, and Tennessee is limited to emission reductions achievable by
the 2023 ozone season. For each of these three states, EPA's analysis
does not consider, nor does the EPA propose to require, emissions
reductions at either EGUs or non-EGUs that cannot be implemented until
the 2026 ozone season.
    At the third step of the 4-step framework, EPA applied a multi-
factor test that incorporates cost, availability of emissions
reductions, and air quality impacts at the downwind receptors to
determine the amount of ozone precursor emissions from the linked
upwind states that ``significantly'' contribute to downwind
nonattainment or maintenance receptors. In this proposed rule, the EPA
proposes to apply the multifactor test described in Section VI.A of
this proposed rule to both EGU and non-EGU sources. The EPA assessed
the potential emissions reductions in 2023 and 2026, as well as in
intervening and later years to determine the emissions reductions
required to eliminate significant contribution in any future year where
downwind areas are projected to have potential problems attaining or
maintaining the 2015 ozone NAAQS.
    For EGU sources, the EPA evaluated the following set of widely-
available NOX emissions control technologies: (1) Fully
operating existing selective catalytic reduction (SCR) controls,
including both optimizing NOX removal by existing
operational SCRs and turning on and optimizing existing idled SCRs; (2)
installing state-of-the-art NOX combustion controls; (3)
fully operating existing selective non-catalytic reduction (SNCR)
controls, including both optimizing NOX removal by existing
operational SNCRs and turning on and optimizing existing idled SNCRs;
(4) installing new SNCRs; (5) installing new SCRs; and (6) generation
shifting. For the reasons explained in Section VI of this proposed rule
and supported by the EGU NOX Mitigation Strategies Proposed
Rule Technical Support Document (TSD) included in the docket for this
proposed rule, the EPA determined that for the regional, multi-state
scale of this rulemaking, only fully operating and optimizing existing
SCRs and existing SNCRs (EGU NOX emissions controls options
1 and 3 in the list earlier) are possible for the 2023 ozone season.
The EPA determined that state-of-the-art NOX combustion
controls at EGUs (emissions control option 2 in the list above) are
available by the beginning of the 2024 ozone season. Based on EPA's
assessment of the earliest possible timeframe for installation of new
SNCR and SCRs (EGU emissions controls options 4 and 5 in the list), the
EPA proposes to require emissions reductions commensurate with these
controls by the beginning of the 2026 ozone season. See Section VI.B.1
of this proposed rule for a full description of

EPA's analysis of NOX emissions mitigation strategies for
EGU sources.
    The EPA proposes control stringency levels that maximize
incremental NOX emissions reduction potential from EGUs and
corresponding downwind ozone air quality improvements to the extent
feasible in each year analyzed. The EPA believes that the required
controls provide cost-effective reductions of NOX emissions
that will provide substantial improvements in downwind ozone air
quality to address interstate transport obligations for the 2015 ozone
NAAQS in a timely manner. These controls represent greater stringency
in upwind EGU controls than in EPA's most recent ozone transport
rulemakings, such as the CSAPR Update and the Revised CSAPR Update.
However, programs to address interstate ozone transport based on the
retrofit of post-combustion controls are by no means unprecedented. In
prior ozone transport rulemakings such as the NOX SIP Call
and the Clean Air Interstate Rule (CAIR), the EPA established EGU
budgets premised on the widespread availability of retrofitting EGUs
with post-combustion emissions controls such as SCR.\14\ While these
programs successfully drove many EGUs to retrofit post-combustion
controls, other EGUs throughout the present geography of linked upwind
states continue to operate without such controls and continue to emit
at relatively high rates more than 20 years after similar units reduced
these emissions under prior interstate ozone transport rulemakings.
---------------------------------------------------------------------------

    \14\ See, e.g., 70 FR 25162, 25205-06 (May 12, 2005).
---------------------------------------------------------------------------

    Furthermore, the CSAPR Update provided only a partial remedy for
eliminating significant contribution for the 2008 ozone NAAQS, as
needed to obtain available reductions by the 2017 ozone season. In that
rule, the EPA made no determination regarding the appropriateness of
more stringent EGU NOX controls that would be required for a
full remedy for interstate transport for the 2008 ozone NAAQS.
Following the remand of the CSAPR Update in Wisconsin v. EPA, 938 F.3d
303 (D.C. Cir. 2019) (Wisconsin), the EPA again declined to require the
retrofit of new post-combustion controls on EGUs in the Revised CSAPR
Update, but that determination was based on a specific timing
consideration: Downwind air quality problems under the 2008 ozone NAAQS
were projected to resolve before post-combustion control retrofits
could be accomplished on a fleetwide, regional scale. See 86 FR 23054,
23110 (April 30, 2021).
    In this proposed rulemaking, the EPA is addressing good neighbor
obligations for the more stringent 2015 ozone NAAQS, and the Agency
observes ongoing and persistent contribution from upwind states to
ozone nonattainment and maintenance receptors in other states under
that NAAQS. As further discussed in Section VI of this proposed rule,
the nature of this contribution warrants a greater degree of control
stringency than the EPA determined to be necessary to eliminate
significant contribution of ozone transport in prior CSAPR rulemakings.
The EPA is therefore returning to EGU NOX control strategies
commensurate with those determined to be necessary in the
NOX SIP Call and CAIR.
    Based on the Step 3 analysis described in Section VI of this
proposed rule, the EPA is proposing that emissions reductions
commensurate with the full operation of all existing post-combustion
controls (both SCRs and SNCRs) and state-of-the-art combustion control
upgrades constitute the Agency's selected control stringency for EGUs
within the borders of 25 states linked to downwind nonattainment or
maintenance in 2023 (Alabama, Arkansas, Delaware, Illinois, Indiana,
Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi,
Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, Pennsylvania,
Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and
Wyoming). For 22 of those states that are also linked in 2026
(Arkansas, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan,
Minnesota, Mississippi, Missouri, Nevada, New Jersey, New York, Ohio,
Oklahoma, Pennsylvania, Texas, Utah, Virginia, West Virginia,
Wisconsin, and Wyoming), the EPA is determining that the selected EGU
control stringency also includes emissions reductions commensurate with
the retrofit of SCR at coal steam units of 100 MW or greater capacity
(excepting circulating fluidized bed units (CFB)), new SNCR on coal
steam units of less than 100 MW capacity and CFBs, and SCR on oil/gas
steam units greater than 100 MW that have historically emitted at least
150 tons of NOX per ozone season.
    To identify appropriate control strategies for non-EGU sources to
achieve NOX emissions reductions that would result in
meaningful air quality improvements in downwind areas, the EPA
developed an analytical framework to evaluate the air quality impacts
of potential emissions reductions from non-EGU sources located in the
linked upwind states. The EPA incorporated air quality modeling
information, annual emissions, and information about potential controls
to determine which industries, if subject to further control
requirements, would have the greatest impact in providing air quality
improvements at the downwind receptors. This evaluation was subject to
a marginal cost threshold of up to $7,500 per ton, which the EPA
determined based on information available to the Agency about existing
control device efficiency and cost information. Additional information
on the analytical framework is described in Section VI.B.2 of this
proposed rule and is presented in the memorandum titled Screening
Assessment of Potential Emissions Reductions, Air Quality Impacts, and
Costs from Non-EGU Emissions Units for 2026 (``Non-EGU Screening
Assessment memorandum''), which is available in the docket for this
proposed rulemaking. Based on the results of this assessment, the EPA
identified emissions unit types in seven industries (identified in
Section I.A.2 of this proposed rule) that provide opportunities for
NOX emissions reductions that result in meaningful impacts
on air quality at the downwind receptors.
    The EPA performed air quality analysis using the Ozone Air Quality
Assessment Tool (AQAT) to determine whether the proposed emissions
reductions for both EGUs and non-EGUs potentially create an ``over-
control'' scenario whereby (1) the expected ozone improvements would be
greater than necessary to resolve the downwind ozone pollution problem
(i.e., beyond what is necessary to resolve all nonattainment and
maintenance problems to which an upwind state is linked) or (2) the
expected ozone improvements would reduce the upwind state's ozone
contributions below the screening threshold (i.e., 1 percent of the
NAAQS or 0.70 ppb). The EPA's over-control analysis, discussed in
Section VI.D.4 of this proposed rule, shows that the proposed control
stringencies for EGU and non-EGU sources do not over-control upwind
states' emissions either with respect to the downwind air quality
problems to which they are linked or with respect to the 1 percent of
the NAAQS contribution threshold, such that over-control would trigger
re-evaluation at Step 3 for any linked upwind state.

    Based on the multi-factor test applied to both EGU and non-EGU
sources and our subsequent assessment of over-control, the EPA finds
that the selected EGU and non-EGU control stringencies constitute the
elimination of significant contribution and interference with
maintenance, without over-controlling emissions, from the 26 upwind
states subject to EGU and non-EGU emissions reductions requirements
under the proposed rule. In order to eliminate significant contribution
and interference with maintenance through the fourth step of the 4-step
framework, as described in Section VII of this proposed rule, the EPA
is establishing emissions budgets for EGUs within the borders of 25
states that reflect the remaining allowable emissions after the
emissions reductions associated with the selected control stringency
have been achieved. For the same reason, the EPA is establishing non-
EGU emissions limits in 23 states that result in the elimination of
significant contribution from non-EGU sources in these states. For
additional details about the test and the over-control analysis, see
the document titled, ``Ozone Transport Policy Analysis Proposed Rule
TSD'' included in the docket for this rulemaking.
    In this fourth step of the 4-step framework, the EPA proposes to
include enforceable measures in the promulgated FIPs to achieve the
required emissions reductions in each of the 26 states. Specifically,
the FIPs would require covered power plants within the borders of the
25 states listed in Table I.A-1 to participate in the CSAPR
NOX Ozone Season Group 3 Trading Program created by the
Revised CSAPR Update. Affected EGUs within the borders of twelve states
currently participating in the Group 3 Trading Program would remain in
the program, with revised provisions beginning in the 2023 ozone
season, under this proposed rule: Illinois, Indiana, Kentucky,
Louisiana, Maryland, Michigan, New Jersey, New York, Ohio,
Pennsylvania, Virginia, and West Virginia. Affected EGUs within the
borders of eight states currently covered by the CSAPR NOX
Ozone Season Group 2 Trading Program (the ``Group 2 trading
program'')--Alabama, Arkansas, Mississippi, Missouri, Oklahoma,
Tennessee, Texas, and Wisconsin--would transition from the Group 2
program to the revised Group 3 trading program beginning with the 2023
control period,\15\ and affected EGUs within the borders of five states
not currently covered by any CSAPR trading program for seasonal
NOX emissions--Delaware, Minnesota, Nevada, Utah, and
Wyoming--would enter the Group 3 trading program in the 2023 control
period following the effective date of the final rule. In addition, the
EPA proposes to revise other aspects of the Group 3 trading program to
help maintain control stringency over time and improve emissions
performance at individual units, offering a necessary measure of
assurance that existing pollution controls will be operated during the
ozone season, as described in Section VII of this proposed rule. This
proposal does not revise the budget stringency and geography of the
existing CSAPR NOX Ozone Season Group 1 trading program.
Aside from the eight states moving from the Group 2 trading program to
the Group 3 trading program under the proposed rule, this proposal
otherwise leaves unchanged the budget stringency of the existing CSAPR
NOX Ozone Season Group 2 trading program.
---------------------------------------------------------------------------

    \15\ The EPA would deem participation in the Group 3 trading
program by the EGUs in these eight states as also addressing the
respective states' good neighbor obligations with respect to the
2008 ozone NAAQS (for all eight states), the 1997 ozone NAAQS (for
all the states except Texas), and the 1979 ozone NAAQS (for Alabama,
Missouri, and Tennessee) to the same extent that those obligations
are currently being addressed by participation of the states' EGUs
in the Group 2 trading program.
---------------------------------------------------------------------------

    The EPA is proposing preset ozone season NOX emissions
budgets for the 2023 and 2024 ozone seasons, as explained in Section
VII.B of this proposed rule and as shown in Table I.B-1.

 Table I.B-1--Proposed and Illustrative CSAPR NOX Ozone Season Group 3 State Emissions Budgets for 2023 Through
                                             2026 Control Periods *
----------------------------------------------------------------------------------------------------------------
                                                     Proposed        Proposed      Illustrative    Illustrative
                                                     emissions       emissions       emissions       emissions
                      State                         budgets for     budgets for     budgets for     budgets for
                                                   2023 control    2024 control    2025 control    2026 control
                                                   period (tons)   period (tons)   period (tons)   period (tons)
----------------------------------------------------------------------------------------------------------------
Alabama.........................................           6,364           6,306           6,306           6,306
Arkansas........................................           8,889           8,889           8,889           3,923
Delaware........................................             384             434             434             434
Illinois........................................           7,364           7,463           7,463           6,115
Indiana.........................................          11,151           9,391           8,714           7,791
Kentucky........................................          11,640          11,640          11,134           7,573
Louisiana.......................................           9,312           9,312           9,179           3,752
Maryland........................................           1,187           1,187           1,187           1,189
Michigan........................................          10,718          10,718          10,759           6,114
Minnesota.......................................           3,921           3,921           3,910           2,536
Mississippi.....................................           5,024           4,400           4,400           1,914
Missouri........................................          11,857          11,857          10,456           7,246
Nevada..........................................           2,280           2,372           2,372           1,211
New Jersey......................................             799             799             799             799
New York........................................           3,763           3,763           3,763           3,238
Ohio............................................           8,369           8,369           8,369           8,586
Oklahoma........................................          10,265           9,573           9,393           4,275
Pennsylvania....................................           8,855           8,855           8,855           6,819
Tennessee.......................................           4,234           4,234           4,008           4,008
Texas...........................................          38,284          38,284          36,619          21,946
Utah............................................          14,981          15,146          15,146           2,620
Virginia........................................           3,090           2,814           2,948           2,567
West Virginia...................................          12,478          12,478          12,478          10,597
Wisconsin.......................................           5,963           5,057           4,198           3,473

Wyoming.........................................           9,125           8,573           8,573           4,490
----------------------------------------------------------------------------------------------------------------
* Further information on the state-level emissions budget calculations pertaining to Table I.B-1 is provided in
  Section VII.B.4 of this proposed rule as well as the Ozone Transport Policy Analysis Proposed Rule TSD.
  Further information on the proposed approach for allocating a portion of Utah's emissions budget for each
  control period to the existing EGU in the Uintah and Ouray Reservation within Utah's borders is provided in
  Section VII.B.9 of this proposed rule.

    Beyond preset emissions budgets for the 2023 and 2024 control
periods, the EPA also proposes to extend the Group 3 trading program
budget-setting methodology used in the Revised CSAPR Update so as to
routinely set emissions budgets for each future control period
(beginning in 2025) in the year before that control period, with each
emissions budget reflecting the latest available information on the
composition and utilization of the EGU fleet at the time that emissions
budget is determined (see Table VII.B.4.c-2 for illustrative examples
of dynamic budget calculations that the EPA will publish in advance of
each ozone season, effective for the 2025 control period and beyond).
The stringency of the dynamic emissions budgets would simply reflect
the stringency of the emissions control strategies selected in the
rulemaking more consistently over time and ensure that the annual
updates would eliminate emissions determined to be unlawful under the
good neighbor provision. See Section VII.B of this proposed rule for
additional discussion of EPA's proposed method for adjusting emissions
budgets to ensure elimination of significant contribution from EGU
sources in the linked upwind states.
    As an enhancement to the structure of the trading program as
originally promulgated in the Revised CSAPR Update, the EPA is also
proposing to establish backstop daily emissions rates for coal steam
units greater than or equal to 100 MW in covered states. Units emitting
in excess of these daily rates would be subject to increased allowance
surrender requirements under the trading program. The backstop daily
emissions rates would work in tandem with the ozone season emissions
budgets to offer downwind stakeholders a necessary measure of assurance
that they will be protected on a daily basis during the ozone season by
continuous operation of installed pollution controls. The EPA's
experience with the CSAPR trading programs has revealed instances where
EGUs have reduced their SCRs' performance on a given day, or across the
entire ozone seasons in some cases, including high ozone days.\16\ In
addition to maintaining a mass-based seasonal requirement, the EPA
proposes to require controls while maintaining as much compliance
flexibility as possible through a unit-level emission rate designed to
ensure that controls operate continuously and that required reductions
occur on the highest ozone days. These trading program improvements
also promote consistent emissions control performance across the power
sector, which protects communities living in downwind ozone
nonattainment areas from exceedances of the NAAQS that might otherwise
occur.
---------------------------------------------------------------------------

    \16\ See 86 FR 23090. The EPA highlighted the Miami Fort Unit 7
(possessing a SCR) more than tripled its ozone-season NOX
emission rate between 2017 and 2019.
---------------------------------------------------------------------------

    The EPA proposes to include enforceable emissions standards that
will apply during the ozone season (annually from May to September) for
seven non-EGU industries in the promulgated FIPs to achieve the
required emissions reductions in 23 states with remaining interstate
transport obligations for the 2015 ozone NAAQS in 2026: Arkansas,
California, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan,
Minnesota, Mississippi, Missouri, Nevada, New Jersey, New York, Ohio,
Oklahoma, Pennsylvania, Texas, Utah, Virginia, West Virginia,
Wisconsin, and Wyoming. These requirements would apply to all existing
emissions units and to any future emissions units constructed in the
covered states after promulgation of the final rule. Thus, the
emissions limits for non-EGU sources and associated compliance
requirements would apply in all 23 states listed in this paragraph,
even if certain of these states do not currently have existing
emissions units within a particular industry.
    Based on our evaluation of the time required to install controls at
the types of non-EGU sources covered by this proposed rule, the EPA has
identified the 2026 ozone season as the earliest compliance date
possible for non-EGU emissions reductions. The EPA is therefore
proposing to include non-EGU emissions reductions beginning in 2026.
For sources located in the 23 states listed in the previous paragraph,
The EPA proposes to require the emissions limits listed in Table I.B-2
for

reciprocating internal combustion engines in Pipeline Transportation of
Natural Gas; the emissions limits listed in Table I.B-3 for kilns in
Cement and Cement Product Manufacturing; the emissions limits listed in
Table I.B-4 for boilers and furnaces in Iron and Steel Mills and
Ferroalloy Manufacturing; the emissions limits listed in Table I.B-5
for furnaces in Glass and Glass Product Manufacturing; and the
emissions limits listed in Table I.B-6 for high-emitting equipment and
large boilers in Basic Chemical Manufacturing, Petroleum and Coal
Products Manufacturing, and Pulp, Paper, and Paperboard Mills.
---------------------------------------------------------------------------

    \17\ Based on source cap equation at 30 TAC Sec.  117.3123(b);
January 14, 2009 (74 FR 1927), Docket ID No. EPA-R06-OAR-2007-1147,
also see https://wayback.archive-it.org/414/20210527223433/https://www.tceq.texas.gov/assets/public/legal/rules/rules/pdflib/117e.pdf.

   Table I.B-2--Summary of Proposed NOX Emissions Limits for Pipeline
                      Transportation of Natural Gas
------------------------------------------------------------------------
                                           Proposed NOX emissions limit
          Engine type and fuel
------------------------------------------------------------------------
Natural Gas Fired Four Stroke Rich Burn.  1.0 g/hp-hr.
Natural Gas Fired Four Stroke Lean Burn.  1.5 g/hp-hr.
Natural Gas Fired Two Stroke Lean Burn..  3.0 g/hp-hr.
------------------------------------------------------------------------

 Table I.B-3--Summary of Proposed NOX Emissions Limits for Kiln Types in
                Cement and Concrete Product Manufacturing
------------------------------------------------------------------------
                                                           Proposed NOX
                                                             emissions
                        Kiln type                          limit (lb/ton
                                                           of  clinker)

------------------------------------------------------------------------
Long Wet................................................             4.0
Long Dry................................................             3.0
Preheater...............................................             3.8
Precalciner.............................................             2.3
Preheater/Precalciner...................................             2.8
------------------------------------------------------------------------

    The EPA is also proposing a source cap limit expressed in ton per
day (tpd) of NOX for each individual cement plant according
to the following equation.\17\
[GRAPHIC] [TIFF OMITTED] TP06AP22.000

Where:

CAP2015 Ozone Transport = total allowable NOX emissions
from all cement kilns located at one cement plant, in tons per day,
on a 30-operating day rolling average basis;
KD = 1.7 pounds NOX per ton of clinker for dry preheater-
precalciner or precalciner kilns;
KW = 3.4 pounds NOX per ton of clinker for long wet
kilns;
ND = the average annual production in tons of clinker plus one
standard deviation for the three most recent calendar years from all
dry preheater-precalciner or precalciner kilns located at one cement
plant; and
NW = the average annual production in tons of clinker plus one
standard deviation for the 3 most recent calendar years from all
long wet kilns located at one cement plant.

    An affected cement plant will need to comply with both the source
cap limit and the specific NOX emissions limits assigned to
its individual kiln type(s). Refer to Section VII.C.2 of this proposed
rule for additional information concerning the application of the
source cap limit to this industry source group.

Table I.B-4--Summary of Proposed NOX Emissions Limits for Iron and Steel
                     and Ferroalloy Emissions Units
------------------------------------------------------------------------
                                         Proposed NOX emissions standard
             Emissions unit              or requirement (lbs/hour or lb/
                                                      mmBtu)
------------------------------------------------------------------------
Blast Furnace..........................  0.03 lb/mmBtu.
Basic Oxygen Furnace...................  0.07 lb/ton.
Electric Arc Furnace...................  0.15 lb/ton steel.
Ladle/tundish Preheaters...............  0.06 lb/mmBtu.
Reheat furnace.........................  0.05 lb/mmBtu.
Annealing Furnace......................  0.06 lb/mmBtu.
Vacuum Degasser........................  0.03 lb/mmBtu.
Ladle Metallurgy Furnace...............  0.1 lb/ton.
Taconite production kilns..............  Work practice standard to
                                          install low NOX technology/
                                          burners, test and set.
Coke ovens (charging and coking).......  0.6 lb/ton of coal charged.
Coke ovens (pushing)...................  0.015 lb/ton of coal pushed.
Boilers--Coal..........................  0.20 lb/mmBtu.
Boilers--Residual oil..................  0.20 lb/mmBtu.
Boilers--Distillate oil................  0.12 lb/mmBtu.
Boilers--Natural gas...................  0.08 lb/mmBtu.
------------------------------------------------------------------------

 Table IV.B-5--Summary of Proposed NOX Emissions Limits for Furnace Unit
             Types in Glass and Glass Product Manufacturing
------------------------------------------------------------------------
                                                         Proposed NOX
                                                        emissions limit
                    Furnace type                       (lb/ton of glass
                                                           produced)
------------------------------------------------------------------------
Container Glass Manufacturing Furnace...............                 4.0
Pressed/Blown Glass Manufacturing Furnace or                         4.0
 Fiberglass Manufacturing Furnace...................
Flat Glass Manufacturing Furnace....................                 9.2
------------------------------------------------------------------------

 Table I.B-6--Summary of Proposed NOX Emissions Limits for High-Emitting
 Equipment and Large Boilers in Basic Chemical Manufacturing, Petroleum
 and Coal Products Manufacturing, and Pulp, Paper, and Paperboard Mills
------------------------------------------------------------------------
                                                             Emissions
                        Unit type                         limit (lbs NOX/
                                                              mmBtu)
------------------------------------------------------------------------
Coal....................................................            0.20
Residual oil............................................            0.20
Distillate oil..........................................            0.12
Natural gas.............................................            0.08
------------------------------------------------------------------------

    Refer to Section VII.C of this proposed rule for applicability
criteria, compliance assurance requirements, and the EPA's rationale in
proposing these emissions limits for each of the non-EGU industries
covered by the proposed rule. In addition, the EPA requests comment on
several topics regarding the implementation of emissions limits for
non-EGU sources that are proposed in this rulemaking, including
controls on emissions units and control installation timing. See
Section VI.D.2.a of this proposed rule for a list of detailed questions
on which the Agency is soliciting public comment.
    The remainder of this preamble is organized as follows: Section III
of this proposed rule outlines general applicability criteria for the
proposed rule and describes the EPA's legal authority for this proposed
rule, the relationship of the proposed rule to previous interstate
ozone transport rulemakings, and the incremental costs and benefits of
the proposed rule; Section IV of this proposed rule describes the human
health and environmental challenges posed by interstate transport
contributions to ozone air quality problems, as well as EPA's overall
approach for addressing interstate transport for the 2015 ozone NAAQS
in this proposed rule; Section V of this proposed rule describes the
Agency's analyses of air quality data to inform this proposed
rulemaking, including descriptions of the air quality modeling platform
and emissions inventories used in the proposed rule, as well as EPA's
methods for identifying downwind air quality problems and upwind
states' ozone transport contributions to downwind states; Section VI of
this proposed rule describes EPA's approach to quantifying upwind
states' obligations in the form of EGU NOX control
stringencies and non-EGU emissions limits; Section VII of this proposed
rule describes key elements of the implementation schedule for EGU and
non-EGU emissions reductions requirements, including details regarding
the revised aspects of the CSAPR NOX Group 3 trading program
and compliance deadlines, as well as regulatory requirements and
compliance deadlines for non-EGU sources; Section VIII of this proposed
rule discusses the environmental justice considerations of the proposed
rule; Section IX of this proposed rule describes the expected costs,
benefits, and other impacts of this proposed rule; Section X of this
proposed rule provides a summary of proposed changes to the existing
regulatory text; and Section XI of this proposed rule discusses the
statutory and executive orders affecting this proposed rulemaking.

C. Costs and Benefits

    A summary of the key results of the cost-benefit analysis that was
prepared for this proposed rule is presented in Table I.C-1. Table I.C-
1 presents estimates of the present values (PV) and equivalent
annualized values (EAV), calculated using discount rates of 3 and 7
percent as directed by OMB's Circular A-4, of the health benefits,
compliance costs, and net benefits of the proposed rule, in 2016
dollars, discounted to 2022. The estimated monetized net benefits are
the estimated monetized benefits minus the estimated monetized costs of
the proposed rule. These results present an incomplete overview of the
effects of the proposal, because important categories of benefits--
including benefits from reducing climate pollution, other types of air
pollutants, and water pollution--were not monetized and are therefore
not reflected in the cost-benefit tables. We anticipate that taking
non-monetized effects into account would show the proposal to be more
net beneficial than this table reflects.

  Table I.C-1--Estimated Monetized Benefits, Compliance Costs, and Net
            Benefits of the Proposed Rule, 2023 Through 2042
                 [Millions 2016$, discounted to 2022] a
------------------------------------------------------------------------
                                   3% Discount rate    7% Discount rate
------------------------------------------------------------------------
Present Value:
    Benefits \b\................             250,000             150,000
    Compliance Costs \c\........              22,000              14,000
                                 ---------------------------------------
        Net Benefits............             220,000             130,000
------------------------------------------------------------------------
Equivalent Annualized Value:
    Benefits....................              17,000              14,000
    Compliance Costs............               1,500               1,300
                                 ---------------------------------------

              Net Benefits......              15,000              12,000
------------------------------------------------------------------------
\a\ Rows may not appear to add correctly due to rounding.
\b\ The annualized present value of costs and benefits are calculated
  over a 20-year period from 2023 to 2042. Monetized benefits include
  those related to public health associated with reductions in PM2.5 and
  ozone concentrations. The health benefits are associated with several
  point estimates and are presented at real discount rates of 3 and 7
  percent. Several categories of benefits remain unmonetized and are
  thus not reflected in the table. Non-monetized benefits include
  important climate benefits from reductions in CO2 emissions. The U.S.
  District Court for the Western District of Louisiana has issued an
  injunction concerning the monetization of the benefits of greenhouse
  gas emission reductions by EPA and other defendants. See Louisiana v.
  Biden, No. 21-cv-01074-JDC-KK (W.D. La. Feb. 11, 2022). Therefore,
  such values are not presented in the benefit-cost analysis of this
  proposal conducted pursuant to E.O. 12866. Please see Chapter 5,
  Section 5.2 of the RIA for more discussion. In addition, there are
  important unquantified water quality benefits and benefits associated
  with reductions in other air pollutants.
\c\ The costs presented in this table are consistent with the costs
  presented in Chapter 4 of the RIA. To estimate these annualized costs,
  EPA uses a conventional and widely accepted approach that applies a
  capital recovery factor (CRF) multiplier to capital investments and
  adds that to the annual incremental operating expenses. Costs were
  calculated using a 3.76% real discount rate consistent with the rate
  used in IPM's objective function for cost-minimization.

    As shown in Table I.C-1, the PV of the benefits, associated with
reductions in PM2.5 and ozone concentrations, of this
proposed rule, discounted at a 3-percent discount rate, is estimated to
be about $250,000 million, with an EAV of about $17,000 million. At a
7-percent discount rate, the PV of the benefits is estimated to be
$150,000 million, with an EAV of about $14,000 million. The PV of the
compliance costs, discounted at a 3-percent rate, is estimated to be
about $22,000 million, with an EAV of about $1,500 million. At a 7-
percent discount rate, the PV of the compliance costs is estimated to
be about $14,000 million, with an EAV of about $1,300 million.

II. Public Participation

A. Written Comments

    Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2021-
0668 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). For additional submission methods, 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. Hand deliveries or couriers will be
received by scheduled appointment only. 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.

B. Submitting Confidential Business Information

    Do not submit information containing CBI to the EPA through https://www.regulations.gov. Clearly mark the part or all of the information
that you claim to be CBI. For CBI information on any digital storage
media that you mail to the EPA, mark the outside of the digital storage
media as CBI and then identify electronically within the digital
storage media the specific information that is claimed as CBI. In
addition to one complete version of the comments that includes
information claimed as CBI, you must submit a copy of the comments that
does not contain the information claimed as CBI directly to the public
docket through the procedures outlined in Instructions earlier. If you
submit any digital storage media that does not contain CBI, mark the
outside of the digital storage media clearly that it does not contain
CBI. Information not marked as CBI will be included in the public
docket and the EPA's electronic public docket without prior notice.
Information marked as CBI will not be disclosed except in accordance
with procedures set forth in 40 Code of Federal Regulations (CFR) part
2. Our preferred method to receive CBI is for it to be transmitted to
electronically using email attachments, File Transfer Protocol (FTP),
or other online file sharing services (e.g., Dropbox, OneDrive, Google
Drive). Electronic submissions must be transmitted directly to the
OAQPS CBI Office using the email address, [email protected], and should
include clear CBI markings as described above. If assistance is needed
with submitting large electronic files that exceed the file size limit
for email attachments, and if you do not have your own file sharing
service, please email [email protected] to request a file transfer link.
If sending CBI information through the postal service, please send it
to the following address: OAQPS Document Control Officer (C404-02),
OAQPS, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2021-0668. The
mailed CBI material should be double wrapped and clearly marked. Any
CBI markings should not show through the outer envelope.

C. Participation in Virtual Public Hearing

    Please note that because of current CDC recommendations, as well as
state and local orders for social distancing to limit the spread of
COVID-19, the EPA cannot hold in-person public meetings at this time.
    The EPA will begin pre-registering speakers for the hearing no
later than 1 business day after publication of this document in the
Federal Register. To

register to speak at the virtual hearing, please use the online
registration form available at https://www.epa.gov/csapr/csapr-2015-ozone-naaqs. The last day to pre-register to speak at the hearing will
be April 21, 2022. The EPA will post a general agenda for the hearing
that will list pre-registered speakers in approximate order at: https://www.epa.gov/csapr/csapr-2015-ozone-naaqs.
    The virtual public hearing will be held on via teleconference on
April 21, 2022. The virtual public hearing will convene at 10:00 a.m.
Eastern Time (ET) and will conclude at 7:00 p.m. ET. The EPA may close
a session 15 minutes after the last pre-registered speaker has
testified if there are no additional speakers. For information or
questions about the public hearing, please contact Ms. Holly DeJong at
[email protected]. The EPA will announce further details at https://www.epa.gov/csapr/csapr-2015-ozone-naaqs.
    The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 5 minutes to provide oral testimony. The
EPA encourages commenters to provide the EPA with a copy of their oral
testimony electronically (via email) by emailing it to
[email protected]. The EPA also recommends submitting the text of
your oral comments as written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations,
but will not respond to the presentations at that time. Written
statements and supporting information submitted during the comment
period will be considered with the same weight as oral comments and
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/csapr/csapr-2015-ozone-naaqs.
While the EPA expects the hearing to go forward as set forth above,
please monitor our website or contact Ms. Holly DeJong at
[email protected] to determine if there are any updates. The EPA
does not intend to publish a document in the Federal Register
announcing updates.
    If you require the services of a translator or special
accommodations such as audio description, please pre-register for the
hearing and describe your needs by April 18, 2022. EPA may not be able
to arrange accommodations without advanced notice.

III. General Information

A. Does this action apply to me?

    This proposed rule affects EGU and non-EGU sources, and regulates
the groups identified in Table III.A-1.

                     Table III.A-1--Regulated Groups
------------------------------------------------------------------------
                        Industry group                            NAICS
------------------------------------------------------------------------
Fossil fuel-fired electric power generation...................    221112
Pipeline Transportation of Natural Gas........................      4862
Cement and Concrete Product Manufacturing.....................      3273
Iron and Steel Mills and Ferroalloy Manufacturing.............      3311
Glass and Glass Product Manufacturing.........................      3272
Basic Chemical Manufacturing..................................      3251
Petroleum and Coal Products Manufacturing.....................      3241
Pulp, Paper, and Paperboard Mills.............................      3221
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
proposed rule. This table lists the types of entities that the EPA is
now aware could potentially be regulated by this proposed rule. Other
types of entities not listed in the table could also be regulated. For
example, the EPA is requesting comment in Section VI.B.3 of this
proposed rule on potential control strategies for sources outside of
the categories listed in the Table III.A.1, such as municipal waste
combustors (MWCs). To determine whether your EGU entity is proposed to
be regulated by this proposed rule, you should carefully examine the
applicability criteria found in 40 CFR 97.1004, which the EPA is not
proposing to alter in this proposed rule. If you have questions
regarding the applicability of this proposed rule to a particular
entity, consult the person listed in the FOR FURTHER INFORMATION
CONTACT section.

B. What action is the Agency taking?

    The EPA evaluated whether interstate ozone transport emissions from
upwind states are significantly contributing to nonattainment, or
interfering with maintenance, of the 2015 ozone NAAQS in any downwind
state using the same 4-step interstate transport framework that was
developed in previous ozone transport rulemakings. The EPA is proposing
to find that emissions reductions are required from EGU and non-EGU
sources in a total of 26 upwind states to eliminate significant
contribution to downwind air quality problems for the 2015 ozone
standard under the interstate transport provision of the CAA. The EPA
will ensure that these NOX emissions reductions are achieved
by issuing proposed FIP requirements for 26 states: Alabama, Arkansas,
California, Delaware, Illinois, Indiana, Kentucky, Louisiana, Maryland,
Michigan, Minnesota, Mississippi, Missouri, Nevada, New Jersey, New
York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Utah, Virginia,
West Virginia, Wisconsin, and Wyoming.
    The EPA is proposing to revise the existing CSAPR Group 3 Trading
Program to include additional states beginning in the 2023 ozone
season. EGUs in five states not currently covered by any CSAPR trading
program for seasonal NOX emissions--Delaware, Minnesota,
Nevada, Utah, and Wyoming--would be added to the CSAPR Group 3 Trading
Program under this proposed rule. EGUs in twelve states currently
participating in the Group 3 Trading Program would remain in the
program under this proposed rule: Illinois, Indiana, Kentucky,
Louisiana, Maryland, Michigan, New Jersey, New York, Ohio,
Pennsylvania, Virginia, and West Virginia. EGUs in eight states
(Alabama, Arkansas, Mississippi, Missouri, Oklahoma, Tennessee, Texas,
and Wisconsin) will transition from the CSAPR Group 2 Trading Program
to the CSAPR Group 3 Trading Program under this proposed rule beginning
in the 2023 ozone season. The EPA proposes to establish control
stringency levels reflecting installation of state-of-the-art
combustion controls on certain covered EGU sources in emissions budgets
beginning in the 2024 ozone season. The EPA proposes to establish
control stringency levels reflecting installation of new SCR or SNCR
controls on certain covered EGU sources in emissions budgets beginning
in the 2026 ozone season.
    As a complement to the ozone season emissions budgets, the EPA is
also proposing to establish backstop daily emissions rates of 0.14 lb/
mmBtu for coal-fired steam units greater than or equal to 100 MW in
covered states. The backstop emissions rates will first apply in 2024
for coal-fired steam sources with existing SCRs, and in 2027 for those
currently without SCRs.
    In this proposed rule, the EPA is proposing to require emissions
limitations for non-EGU sources in 23 states: Arkansas, California,
Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Minnesota,
Mississippi, Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma,
Pennsylvania, Texas, Utah, Virginia, West Virginia, Wisconsin, and

Wyoming. In these states, EPA is proposing to require emissions
limitations for the following unit types in non-EGU industries:
Furnaces in Glass and Glass Product Manufacturing; boilers and furnaces
in Iron and Steel Mills and Ferroalloy Manufacturing; kilns in Cement
and Cement Product Manufacturing; reciprocating internal combustion
engines in Pipeline Transportation of Natural Gas; and high-emitting
equipment and large boilers in Basic Chemical Manufacturing, Petroleum
and Coal Products Manufacturing, and Pulp, Paper, and Paperboard Mill.
See Table III.A-1 for a list of NAICS codes for each entity included
for regulation under this proposed rule.
    The proposed rule would reduce the transport of ozone precursor
emissions to downwind areas, which is protective of human health and
the environment because acute and chronic exposure to ozone are both
associated with negative health impacts. Ozone exposure is also
associated with negative effects on ecosystems. Additional information
on the human health and environmental benefits from the air quality
issues addressed by this proposed rule are included in Section IV of
this proposed rule.

C. What is the Agency's legal authority for taking this action?

1. Statutory Authority
    The statutory authority for this proposed rule is provided by the
CAA as amended (42 U.S.C. 7401 et seq.). Specifically, sections 110 and
301 of the CAA provide the primary statutory underpinnings for this
proposed rule. The most relevant portions of CAA section 110 are
subsections 110(a)(1), 110(a)(2) (including 110(a)(2)(D)(i)(I)),
110(c)(1), and 110(k)(6)).
    CAA section 110(a)(1) provides that states must make SIP
submissions ``within 3 years (or such shorter period as the
Administrator may prescribe) after the promulgation of a national
primary ambient air quality standard (or any revision thereof),'' and
that these SIP submissions are to provide for the ``implementation,
maintenance, and enforcement'' of such NAAQS.\18\ The statute directly
imposes on states the duty to make these SIP submissions, and the
requirement to make the submissions is not conditioned upon the EPA
taking any action other than promulgating a new or revised NAAQS.\19\
---------------------------------------------------------------------------

    \18\ 42 U.S.C. 7410(a)(1).
    \19\ See EPA v. EME Homer City Generation, L.P., 572 U.S. 489,
509-10 (2014).
---------------------------------------------------------------------------

    The EPA has historically referred to SIP submissions made for the
purpose of satisfying the applicable requirements of CAA sections
110(a)(1) and 110(a)(2) as ``infrastructure SIP'' or ``iSIP''
submissions. CAA section 110(a)(1) addresses the timing and general
requirements for iSIP submissions, and CAA section 110(a)(2) provides
more details concerning the required content of these submissions.\20\
It includes a list of specific elements that ``[e]ach such plan'' must
address.\21\
---------------------------------------------------------------------------

    \20\ 42 U.S.C. 7410(a)(2).
    \21\ EPA's general approach to infrastructure SIP submissions is
explained in greater detail in individual notices acting or
proposing to act on state infrastructure SIP submissions and in
guidance. See, e.g., Memorandum from Stephen D. Page on Guidance on
Infrastructure State Implementation Plan (SIP) Elements under Clean
Air Act Sections 110(a)(1) and 110(a)(2) (September 13, 2013).
---------------------------------------------------------------------------

    CAA section 110(c)(1) requires the Administrator to promulgate a
FIP at any time within two years after the Administrator: (1) Finds
that a state has failed to make a required SIP submission; (2) finds a
SIP submission to be incomplete pursuant to CAA section 110(k)(1)(C);
or (3) disapproves a SIP submission. This obligation applies unless the
state corrects the deficiency through a SIP revision that the
Administrator approves before the FIP is promulgated.\22\
---------------------------------------------------------------------------

    \22\ 42 U.S.C. 7410(c)(1).
---------------------------------------------------------------------------

    CAA section 110(a)(2)(D)(i)(I), also known as the ``good neighbor''
provision, provides the primary basis for this proposed rule.\23\ It
requires that each state SIP include provisions sufficient to
``prohibit[ ], consistent with the provisions of this subchapter, any
source or other type of emissions activity within the State from
emitting any air pollutant in amounts which will--(I) contribute
significantly to nonattainment in, or interfere with maintenance by,
any other State with respect to any [NAAQS].'' \24\ The EPA often
refers to the emissions reduction requirements under this provision as
``good neighbor obligations'' and submissions addressing these
requirements as ``good neighbor SIPs.''
---------------------------------------------------------------------------

    \23\ 42 U.S.C. 7410(a)(2)(D)(i)(I).
    \24\ Id.
---------------------------------------------------------------------------

    Once EPA promulgates a NAAQS, the EPA must designate areas as being
in ``attainment'' or ``nonattainment'' of the NAAQS, or
``unclassifiable.'' CAA section 107(d).\25\ For ozone, nonattainment is
further split into five classifications based on the severity of the
violation--Marginal, Moderate, Serious, Severe, or Extreme. Higher
classifications provide states with progressively more time to attain
while imposing progressively more stringent control requirements. See
CAA sections 181, 182.\26\ In general, states with nonattainment areas
classified as Moderate or higher must submit plans to EPA to bring
these areas into attainment according to the statutory schedule. CAA
section 182.\27\ If an area fails to attain the NAAQS by the attainment
date associated with its classification, it is ``bumped up'' to the
next classification. CAA section 181(b).\28\
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    \25\ 42 U.S.C. 7407(d).
    \26\ 42 U.S.C. 7511, 7511a.
    \27\ 42 U.S.C. 7511a.
    \28\ 42 U.S.C. 7511(b).
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    Section 301(a)(1) of the CAA gives the Administrator the general
authority to prescribe such regulations as are necessary to carry out
functions under the Act.\29\ Pursuant to this section, EPA has
authority to clarify the applicability of CAA requirements and
undertake other rulemaking action as necessary to implement CAA
requirements. CAA section 301 affords the Agency any additional
authority that may be needed in order to make certain other changes to
its regulations under 40 CFR parts 52, 75, 78, and 97, in order to
effectuate the purposes of the Act. Such changes are discussed in
Section X of this proposed rule.
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    \29\ 42 U.S.C. 7601(a)(1).
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    Section 110(k)(6) of the CAA gives the Administrator authority,
without any further submission from a state, to revise certain prior
actions, including actions to approve SIPs, upon determining that those
actions were in error.\30\ The EPA proposes to make an error correction
under CAA section 110(k)(6) with respect to its prior approval of the
2015 ozone transport SIP submission from the State of Delaware. This is
further discussed in Section IV.C.1 of the proposed rule.
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    \30\ 42 U.S.C. 7410(k)(6).
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    Tribes are not required to submit state implementation plans.
However, as explained in EPA's regulations outlining Tribal Clean Air
Act authority, the EPA is authorized to promulgate FIPs for Indian
country as necessary or appropriate to protect air quality if a tribe
does not submit, and obtain EPA approval of, an implementation plan.
See 40 CFR 49.11(a); see also CAA section 301(d)(4).\31\ In this
proposed rule, the EPA proposes an ``appropriate or necessary'' finding
under CAA section 301(d) and proposes tribal FIP(s) as necessary to
implement the relevant requirements. This is further discussed in
Section IV.C.2 of the proposed rule.
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    \31\ 42 U.S.C. 7601(d)(4).

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D. What actions has EPA previously issued to address regional ozone
transport?

    The EPA has issued several major rules interpreting and clarifying
the requirements of CAA section 110(a)(2)(D)(i)(I) with respect to the
regional transport of ozone. These rules, and the associated court
decisions addressing these rules, summarized here, provide important
direction regarding the requirements of CAA section 110(a)(2)(D)(i)(I).
    The ``NOX SIP Call,'' promulgated in 1998, addressed the
good neighbor provision for the 1979 1-hour ozone NAAQS.\32\ The rule
required 22 states and the District of Columbia to amend their SIPs to
reduce NOX emissions that contribute to ozone nonattainment
in downwind states. The EPA set ozone season NOX budgets for
each state, and the states were given the option to participate in a
regional allowance trading program, known as the NOX Budget
Trading Program.\33\ The D.C. Circuit largely upheld the NOX
SIP Call in Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000), cert.
denied, 532 U.S. 904 (2001).
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    \32\ Finding of Significant Contribution and Rulemaking for
Certain States in the Ozone Transport Assessment Group Region for
Purposes of Reducing Regional Transport of Ozone, 63 FR 57356 (Oct.
27, 1998). As originally promulgated, the NOX SIP Call
also addressed good neighbor obligations under the 1997 8-hour ozone
NAAQS, but EPA subsequently stayed and later rescinded the rule's
provisions with respect to that standard. See 84 FR 8422 (March 8,
2019).
    \33\ ``Allowance Trading,'' sometimes referred to as ``cap and
trade,'' is an approach to reducing pollution that has been used
successfully to protect human health and the environment. The design
elements of EPA's most recent trading programs are discussed in
Section VII.B.1.a of this proposed rule.
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    EPA's next rule addressing the good neighbor provision, the Clean
Air Interstate Rule (CAIR), was promulgated in 2005 and addressed both
the 1997 fine particulate matter (PM2.5) NAAQS and 1997
ozone NAAQS.\34\ CAIR required SIP revisions in 28 states and the
District of Columbia to reduce emissions of sulfur dioxide
(SO2) or NOX--important precursors of regionally
transported PM2.5 (SO2 and annual NOX)
and ozone (summer-time NOX). As in the NOX SIP
Call, states were given the option to participate in regional trading
programs to achieve the reductions. When the EPA promulgated the final
CAIR in 2005, the EPA also issued findings that states nationwide had
failed to submit SIPs to address the requirements of CAA section
110(a)(2)(D)(i) with respect to the 1997 PM2.5 and 1997
ozone NAAQS.\35\ On March 15, 2006, the EPA promulgated FIPs to
implement the emissions reductions required by CAIR.\36\ CAIR was
remanded to EPA by the D.C. Circuit in North Carolina v. EPA, 531 F.3d
896 (D.C. Cir. 2008), modified on reh'g, 550 F.3d 1176. For more
information on the legal issues underlying CAIR and the D.C. Circuit's
holding in North Carolina, refer to the preamble of the CSAPR rule.\37\
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    \34\ Rule To Reduce Interstate Transport of Fine Particulate
Matter and Ozone (Clean Air Interstate Rule); Revisions to Acid Rain
Program; Revisions to the NOX SIP Call, 70 FR 25162 (May
12, 2005).
    \35\ 70 FR 21147 (April 25, 2005).
    \36\ 71 FR 25328 (April 28, 2006).
    \37\ Federal Implementation Plans: Interstate Transport of Fine
Particulate Matter and Ozone and Correction of SIP Approvals, 76 FR
48208, 48217 (August 8, 2011).
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    In 2011, the EPA promulgated CSAPR to address the issues raised by
the remand of CAIR. CSAPR addressed the two NAAQS at issue in CAIR and
additionally addressed the good neighbor provision for the 2006
PM2.5 NAAQS.\38\ CSAPR required 28 states to reduce
SO2 emissions, annual NOX emissions, or ozone
season NOX emissions that significantly contribute to other
states' nonattainment or interfere with other states' abilities to
maintain these air quality standards.\39\ To align implementation with
the applicable attainment deadlines, the EPA promulgated FIPs for each
of the 28 states covered by CSAPR. The FIPs require EGUs in the covered
states to participate in regional trading programs to achieve the
necessary emissions reductions. Each state can submit a good neighbor
SIP at any time that, if approved by EPA, would replace the CSAPR FIP
for that state.
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    \38\ 76 FR 48208.
    \39\ CSAPR was revised by several rulemakings after its initial
promulgation in order to revise certain states' budgets and to
promulgate FIPs for five additional states addressing the good
neighbor obligation for the 1997 ozone NAAQS. See 76 FR 80760
(December 27, 2011); 77 FR 10324 (February 21, 2012); 77 FR 34830
(June 12, 2012).
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    CSAPR was the subject of an adverse decision by the D.C. Circuit in
August 2012.\40\ However, this decision was reversed in April 2014 by
the Supreme Court, which largely upheld the rule, including EPA's
approach to addressing interstate transport in CSAPR. EPA v. EME Homer
City Generation, L.P., 572 U.S. 489 (2014) (EME Homer City I). The rule
was remanded to the D.C. Circuit to consider claims not addressed by
the Supreme Court. Id. In July 2015 the D.C. Circuit generally affirmed
EPA's interpretation of various statutory provisions and EPA's
technical decisions. EME Homer City Generation, L.P. v. EPA, 795 F.3d
118 (2015) (EME Homer City II). However, the court remanded the rule
without vacatur for reconsideration of EPA's emissions budgets for
certain states, which the court found may have over-controlled those
states' emissions with respect to the downwind air quality problems to
which the states were linked. Id. at 129-30, 138. For more information
on the legal issues associated with CSAPR and the Supreme Court's and
D.C. Circuit's decisions in the EME Homer City litigation, refer to the
preamble of the CSAPR Update.\41\
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    \40\ On August 21, 2012, the D.C. Circuit issued a decision in
EME Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012),
vacating CSAPR. The EPA sought review with the D.C. Circuit en banc
and the D.C. Circuit declined to consider EPA's appeal en banc. EME
Homer City Generation, L.P. v. EPA, No. 11-1302 (D.C. Cir. January
24, 2013), ECF No. 1417012 (denying EPA's motion for rehearing en
banc).
    \41\ Cross-State Air Pollution Rule Update for the 2008 Ozone
NAAQS, 81 FR 74504, 74511 (October 26, 2016).
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    In 2016, the EPA promulgated the CSAPR Update to address interstate
transport of ozone pollution with respect to the 2008 ozone NAAQS.\42\
The final rule updated the CSAPR ozone season NOX emissions
budgets for 22 states to achieve cost-effective and immediately
feasible NOX emissions reductions from EGUs within those
states.\43\ The EPA aligned the analysis and implementation of the
CSAPR Update with the 2017 ozone season in order to assist downwind
states with timely attainment of the 2008 ozone NAAQS.\44\ The CSAPR
Update implemented the budgets through FIPs requiring sources to
participate in a revised CSAPR NOX ozone season trading
program beginning with the 2017 ozone season. As under CSAPR, each
state could submit a good neighbor SIP at any time that, if approved by
the EPA, would replace the CSAPR Update FIP for that state. The final
CSAPR Update also addressed the remand by the D.C. Circuit of certain
states' CSAPR phase 2 ozone season NOX emissions budgets in
EME Homer City II.
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    \42\ 81 FR 74504.
    \43\ One state, Kansas, was made newly subject to ozone season
NOX requirements by the CSAPR Update. All other CSAPR
Update states were already subject to ozone season NOX
requirements under CSAPR.
    \44\ 81 FR 74516. EPA's final 2008 Ozone NAAQS SIP Requirements
Rule, 80 FR 12264, 12268 (March 6, 2015), revised the attainment
deadline for ozone nonattainment areas designated as Moderate to
July 20, 2018. See 40 CFR 51.1103. In order to demonstrate
attainment by this deadline, states were required to rely on design
values calculated using ozone season data from 2015 through 2017,
since the July 20, 2018, deadline did not afford enough time for
measured data of the full 2018 ozone season.
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    In December 2018, the EPA promulgated the CSAPR ``Close-Out,''
which determined that no further enforceable reductions in emissions of
NOX were required with respect to the

2008 ozone NAAQS for 20 of the 22 eastern states covered by the CSAPR
Update, and reflected that determination in revisions to the existing
state-specific sections of the CSAPR Update regulations for those
states.\45\
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    \45\ Determination Regarding Good Neighbor Obligations for the
2008 Ozone National Ambient Air Quality Standard, 83 FR 65878, 65882
(Dec. 21, 2018). After promulgating the CSAPR Update and before
promulgating the CSAPR Close-Out, the EPA approved a SIP from
Kentucky resolving the Commonwealth's good neighbor obligations for
the 2008 ozone NAAQS. 83 FR 33730 (July 17, 2018). In the Revised
CSAPR Update, the EPA made an error correction under CAA section
110(k)(6) to convert this approval to a disapproval, because the
Kentucky approval relied on the same analysis which the D.C. Circuit
determined to be unlawful in the CSAPR Close-Out.
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    The CSAPR Update and the CSAPR Close-Out were both subject to legal
challenges in the D.C. Circuit. Wisconsin v. EPA, 938 F.3d 303 (D.C.
Cir. 2019) (Wisconsin); New York v. EPA, 781 Fed. App'x 4 (D.C. Cir.
2019) (New York). In September 2019, the D.C. Circuit upheld the CSAPR
Update in virtually all respects but remanded the rule because it was
partial in nature and did not fully eliminate upwind states'
significant contribution to nonattainment or interference with
maintenance of the 2008 ozone NAAQS by ``the relevant downwind
attainment deadlines'' in the CAA. Wisconsin, 938 F.3d at 313-15. In
October 2019, the D.C. Circuit vacated the CSAPR Close-Out on the same
grounds that it remanded the CSAPR Update in Wisconsin, specifically
that the Close-Out rule did not address good neighbor obligations by
``the next applicable attainment date'' of downwind states. New York,
781 Fed. App'x at 7.\46\
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    \46\ Subsequently, the D.C. Circuit made clear in a decision
reviewing EPA's denial of a petition under CAA section 126 that the
holding in Wisconsin regarding alignment with downwind area's
attainment schedules applies with equal force to the Marginal area
attainment date established under CAA section 181(a). See Maryland
v. EPA, 958 F.3d 1185, 1203-04 (D.C. Cir. 2020).
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    In response to the Wisconsin remand of the CSAPR Update and the New
York vacatur of the CSAPR Close-Out, the EPA promulgated the Revised
CSAPR Update on April 30, 2021.\47\ The Revised CSAPR Update found that
the CSAPR Update was a full remedy for nine of the covered states. For
the 12 remaining states, the EPA found that their projected 2021 ozone
season NOX emissions significantly contribute to downwind
states' nonattainment or maintenance problems. The EPA issued new or
amended FIPs for these 12 states and required implementation of revised
emissions budgets for EGUs beginning with the 2021 ozone season. Based
on EPA's assessment of remaining air quality issues and additional
emissions control strategies for EGUs and emissions sources in other
industry sectors (non-EGUs), the EPA determined that the NOX
emissions reductions achieved by the Revised CSAPR Update fully
eliminated these states' significant contributions to downwind air
quality problems for the 2008 ozone NAAQS. As under the CSAPR and the
CSAPR Update, each state can submit a good neighbor SIP at any time
that, if approved by EPA, would replace the Revised CSAPR Update FIP
for that state.\48\
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    \47\ Revised Cross-State Air Pollution Rule Update for the 2008
Ozone NAAQS, 86 FR 23054 (April 30, 2021).
    \48\ The Revised CSAPR Update is currently subject to a petition
for judicial review pending in the D.C. Circuit Court of Appeals,
Midwest Ozone Group v. EPA, No. 21-1146 (D.C. Cir. June 25, 2021).
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IV. Air Quality Issues Addressed and Overall Approach for the Proposed
Rule

A. The Interstate Ozone Transport Air Quality Challenge

1. Nature of Ozone and the Ozone NAAQS
    Ground-level ozone is not emitted directly into the air but is
created by chemical reactions between NOX and volatile
organic compounds (VOCs) in the presence of sunlight. Emissions from
electric utilities and industrial facilities, motor vehicles, gasoline
vapors, and chemical solvents are some of the major sources of
NOX and VOCs.
    Because ground-level ozone formation increases with temperature and
sunlight, ozone levels are generally higher during the summer months.
Increased temperature also increases emissions of volatile man-made and
biogenic organics and can also indirectly increase NOX
emissions (e.g., increased electricity generation for air
conditioning).
    On October 1, 2015, the EPA strengthened the primary and secondary
ozone standards to 70 ppb as an 8-hour level.\49\ Specifically, the
standards require that the 3-year average of the fourth highest 24-hour
maximum 8-hour average ozone concentration may not exceed 70 ppb as a
truncated value (i.e., digits to right of decimal removed).\50\ In
general, areas that exceed the ozone standard are designated as
nonattainment areas, pursuant to the designations process under CAA
section 107, and are subject to heightened planning requirements
depending on the degree of severity of their nonattainment
classification, see CAA sections 181, 182.
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    \49\ 80 FR 65291.
    \50\ 40 CFR part 50, Appendix P to part 50
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    In the process of setting the 2015 ozone NAAQS, the EPA noted that
the conditions conducive to the formation of ozone (i.e., seasonally-
dependent factors such as ambient temperature, strength of solar
insolation, and length of day) differ by location, and that the Agency
believes it is important that ozone monitors operate during all periods
when there is a reasonable possibility of ambient levels approaching
the level of the NAAQS. At that time, the EPA stated that ambient ozone
concentrations in many areas could approach or exceed the level of the
NAAQS, more frequently and during more months of the year compared with
the historical ozone season monitoring lengths. Consequently, the EPA
extended the ozone monitoring season for many locations. See 80 FR
65416 for more details.
    Furthermore, the EPA stated that in addition to being affected by
changing emissions, future ozone concentrations may also be affected by
climate change. Modeling studies in the EPA's Interim Assessment (U.S.
EPA, 2009a) that are cited in support of the 2009 Endangerment Finding
under CAA section 202(a) (74 FR 66496, Dec. 15, 2009) as well as a
recent assessment of potential climate change impacts (Fann et al.,
2015) project that climate change may lead to future increases in
summer ozone concentrations across the contiguous U.S.\51\ (80 FR
65300). The increase in ozone results from changes in local weather
conditions, including temperature and atmospheric circulation patterns,
as well as changes in ozone precursor emissions that are influenced by
meteorology (Nolte et al., 2018). While the projected impact may not be
uniform, climate change has the potential to increase average
summertime ozone relative to a future without climate
change.52 53 54 Climate

change has the potential to offset some of the improvements in ozone
air quality, and therefore some of the improvements in public health,
that are expected from reductions in emissions of ozone precursors (80
FR 65300).
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    \51\ These modeling studies are based on coupled global climate
and regional air quality models and are designed to assess the
sensitivity of U.S. air quality to climate change. A wide range of
future climate scenarios and future years have been modeled and
there can be variations in the expected response in U.S. O\3\ by
scenario and across models and years, within the overall signal of
higher summer O\3\ concentrations in a warmer climate.
    \52\ Fann NL, Nolte CG, Sarofim MC, Martinich J, Nassikas NJ.
Associations Between Simulated Future Changes in Climate, Air
Quality, and Human Health. JAMA Netw Open. 2021;4(1):e2032064. doi:
10.1001/jamanetworkopen.2020.32064.
    \53\ Christopher G Nolte, Tanya L Spero, Jared H Bowden, Marcus
C Sarofim, Jeremy Martinich, Megan S Mallard. Regional temperature-
ozone relationships across the U.S. under multiple climate and
emissions scenarios. J Air Waste Manag Assoc. 2021 Oct;71(10):1251-
1264. doi: 10.1080/10962247.2021.1970048.
    \54\ Nolte, C.G., P.D. Dolwick, N. Fann, L.W. Horowitz, V. Naik,
R.W. Pinder, T.L. Spero, D.A. Winner, and L.H. Ziska, 2018: Air
Quality. In Impacts, Risks, and Adaptation in the United States:
Fourth National Climate Assessment, Volume II [Reidmiller, D.R.,
C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K.
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research
Program, Washington, DC, USA, pp. 512-538. doi: 10.7930/
NCA4.2018.CH13.
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2. Ozone Transport
    Studies have established that ozone formation, atmospheric
residence, and transport occur on a regional scale (i.e., thousands of
kilometers) over much of the U.S.\55\ While substantial progress has
been made in reducing ozone in many areas, the interstate transport of
ozone precursor emissions remains an important contributor to peak
ozone concentrations and high-ozone days during the summer ozone
season.
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    \55\ Bergin, M.S. et al. (2007) Regional air quality: Local and
interstate impacts of NOX and SO2 emissions on
ozone and fine particulate matter in the eastern United States.
Environmental Sci & Tech. 41: 4677-4689.
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    The EPA has previously concluded in the NOX SIP Call,