[Federal Register Volume 81, Number 222 (Thursday, November 17, 2016)]
[Proposed Rules]
[Pages 81276-81317]
[FR Doc No: 2016-27333]

Vol. 81

Thursday,

No. 222

November 17, 2016

Part III

Environmental Protection Agency

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40 CFR Parts 50 and 51

Implementation of the 2015 National Ambient Air Quality Standards for
Ozone: Nonattainment Area Classifications and State Implementation Plan
Requirements; Proposed Rule

Federal Register / Vol. 81 , No. 222 / Thursday, November 17, 2016 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 50 and 51

[EPA-HQ-OAR-2016-0202; FRL-9950-24-OAR]
RIN 2060-AS82

Implementation of the 2015 National Ambient Air Quality Standards
for Ozone: Nonattainment Area Classifications and State Implementation
Plan Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing
nonattainment area classification thresholds and implementation
requirements for the strengthened 2015 ozone national ambient air
quality standards (NAAQS) (2015 ozone NAAQS) that were promulgated on
October 1, 2015. This proposal is largely an update to the implementing
regulations previously promulgated for the 2008 ozone NAAQS, and we
propose to retain without significant revision the majority of those
provisions to implement the 2015 ozone NAAQS. This proposal addresses
the timing of attainment dates for each nonattainment area
classification and a range of nonattainment area state implementation
plan (SIP) requirements for the 2015 ozone NAAQS. The proposed SIP
requirements pertain to attainment demonstrations, reasonable further
progress (RFP) and associated milestone demonstrations, reasonably
available control technology (RACT), reasonably available control
measures (RACM), major nonattainment new source review (NNSR), emission
inventories, the timing of required SIP submissions, and compliance
with emission control measures in the SIP. Other issues addressed in
this proposed rule are the revocation of the 2008 ozone NAAQS, anti-
backsliding requirements that would apply when the 2008 ozone NAAQS are
revoked, and reconsideration of the ozone NAAQS interprecursor trading
(IPT) provisions (in response to a petition for reconsideration).

DATES: Comments. Written comments must be received on or before January
17, 2017. Public Hearing. If anyone contacts us requesting a hearing on
or before December 2, 2016, we will hold a hearing. Additional
information about the hearing, if requested, will be published in a
subsequent Federal Register document. Information Collection Request.
Under the Paperwork Reduction Act (PRA), comments on the information
collection provisions are best assured of having full effect if the
Office of Management and Budget (OMB) receives a copy of your comments
on or before December 19, 2016.

ADDRESSES: Comments: Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2016-0202, at http://www.regulations.gov. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from Regulations.gov. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. 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 http://www2.epa.gov/dockets/comments.html.

FOR FURTHER INFORMATION CONTACT: For further general information on
this proposed rule, contact Mr. Robert Lingard, Office of Air Quality
Planning and Standards (OAQPS), U.S. EPA, at<PHONE_NUMBER> or
<EMAIL_ADDRESS>or Mr. Lynn Dail, OAQPS, U.S. EPA, at (919)
541-2363 or<EMAIL_ADDRESS>For information on the Information
Collection Request (ICR), contact Mr. Butch Stackhouse, OAQPS, U.S.
EPA, at<PHONE_NUMBER> or<EMAIL_ADDRESS>For information on
the public hearing, contact Ms. Pamela Long, OAQPS, U.S. EPA, at (919)
541-0641 or<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. General Information

A. Preamble Glossary of Terms and Acronyms

    The following are abbreviations of terms used in the preamble.

ACT Alternative Control Techniques
AERR Air Emissions Reporting Requirements
AVERT AVoided Emissions geneRation Tool
BSMP Basic Smoke Management Practices
CAA Clean Air Act
CAIR Clean Air Interstate Rule
CBI Confidential Business Information
CFR Code of Federal Regulations
CO Carbon Monoxide
CSAPR Cross-State Air Pollution Rule
CTG Control Techniques Guidelines
DOI Department of the Interior
DOT Department of Transportation
DV Design Value
EE/RE Energy Efficiency and Renewable Energy
EPA Environmental Protection Agency
FIP Federal Implementation Plan
FLM Federal Land Managers
FR Federal Register
ICR Information Collection Request
I/M Inspection and Maintenance
IPT Interprecursor Trade or Interprecursor Trading
MCD Milestone Compliance Demonstration
MPO Metropolitan Planning Organization
NAAQS National Ambient Air Quality Standards
NNSR Nonattainment New Source Review
NOX Nitrogen Oxides
O3 Ozone
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OTR Ozone Transport Region
PAMS Photochemical Assessment Monitoring Station
PM2.5 Fine Particulate Matter
ppm Parts per Million
PRA Paperwork Reduction Act
PSD Prevention of Significant Deterioration
PTE Potential to Emit
PUC Public Utility Commission
RACM Reasonably Available Control Measures
RACT Reasonably Available Control Technology
RFP Reasonable Further Progress
ROP Rate of Progress
RPS Renewable Portfolio Standard
SIP State Implementation Plan
SO2 Sulfur Dioxide
tpy Tons per Year
TAR Tribal Authority Rule
TAS Treatment as a State
TGD Technical Guidance Document
TIP Tribal Implementation Plan
TIP Transportation Improvement Program
TSD Technical Support Document
USB U.S. Background
U.S.C. United States Code
USDA U.S. Department of Agriculture
VOC Volatile Organic Compounds

B. Does this action apply to me?

    Entities potentially affected directly by this proposed rule
include state, local and tribal governments and air pollution control
agencies (``air agencies'') responsible for attainment and maintenance
of the NAAQS. Entities potentially affected indirectly by this proposed
rule as regulated sources include owners and operators of sources of
emissions of volatile organic compounds (VOCs) and nitrogen oxides

(NOX) that contribute to ground-level ozone formation.

C. What should I consider as I prepare my comments for the EPA?

    When submitting comments, remember to:
     Identify the rulemaking docket by docket number and other
identifying information (subject heading, Federal Register date and
page number).
     Follow directions. The proposed rule may ask you to
respond to specific questions or organize comments by referencing a
Code of Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives
and substitute language for your requested changes.
     Describe any assumptions and provide any technical
information and/or data that you used to support your comment.
     If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
     Provide specific examples to illustrate your concerns
wherever possible, and suggest alternatives.
     Explain your views as clearly as possible, avoiding the
use of profanity or personal threats.
     Make sure to submit your comments by the comment period
deadline identified.

D. How can I find information about a possible hearing?

    To request a public hearing or information pertaining to a public
hearing regarding this document, contact Ms. Pamela Long, OAQPS, U.S.
EPA, at<PHONE_NUMBER> or<EMAIL_ADDRESS>
E. Where can I get a copy of this document and other related
information?

    In addition to being available in the docket, an electronic copy of
this Federal Register document will be posted at http://www.epa.gov/ozone-pollution.

F. How is this notice of proposed rulemaking organized?

    The information and proposals presented in this notice are
organized as follows:

I. General Information
    A. Preamble Glossary of Terms and Acronyms
    B. Does this action apply to me?
    C. What should I consider as I prepare my comments for the EPA?
    D. How can I find information about a possible hearing?
    E. Where can I get a copy of this document and other related
information?
    F. How is this notice of proposed rulemaking organized?
II. Summary of Proposed Rule and Background
III. Provisions of the 2008 Ozone NAAQS Implementing Regulations To
Be Retained Without Significant Revision
    A. Submitting Nonattainment Area and OTR SIP Elements Due Under
CAA Sections 182 and 184 for the 2015 Ozone NAAQS
    B. Applicability of Existing NAAQS Implementation Provisions in
40 CFR Part 51
    C. General Classification and Nonattainment Area Planning
Provisions
    D. Redesignation to Nonattainment Following Initial Designations
    E. Determining Eligibility for 1-Year Attainment Date Extensions
for the 2015 Ozone NAAQS Under CAA Section 181(a)(5)
    F. Modeling and Attainment Demonstration Requirements
    G. Requirements for RFP
    H. Requirements for RACT and RACM
    I. CAA Section 182(f) NOX Exemption Provisions
    J. General Nonattainment NSR Requirements
    K. Ambient Monitoring Requirements
    L. Requirements for an OTR
    M. Fee Programs for Severe and Extreme Nonattainment Areas That
Fail To Attain
    N. Applicability
IV. Provisions of the 2008 Ozone NAAQS Implementing Regulations To
Be Retained With Specific Revisions
    A. Application of Classification and Attainment Date Provisions
in CAA Section 181 to Areas Subject to Subpart 2 of Part D of Title
I of the CAA
    B. Transition From the 2008 Ozone NAAQS to the 2015 Ozone NAAQS
and Anti-Backsliding Requirements
    C. Requirements for RFP: Milestone Compliance Demonstrations
(MCD)
    D. Requirements for RACT: Deadlines for Submittal and
Implementation of RACT SIP Revisions
    E. Requirements for RACM: Consideration of Sources of Intrastate
Transport of Pollution
    F. Nonattainment NSR Offset Requirement: Interprecursor Trading
for Ozone Offsets
    G. Emissions Inventory and Emissions Statement Requirements
V. Additional Considerations
    A. Managing Emissions From Wildfire and Wildland Prescribed Fire
    B. Transportation Conformity and General Conformity
    C. Requirements for Contingency Measures in the Event of Failure
To Meet a Milestone or To Attain
    D. International Transport and Background Ozone
    E. Additional Policies and Programs for Achieving Emissions
Reductions
    F. Additional Requirements Related to Enforcement and Compliance
    G. Applicability of Proposed Rule to Tribes
VI. Environmental Justice Considerations
VII. 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 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 (NTTA)
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
VIII. Statutory Authority

II. Summary of Proposed Rule and Background

    On October 1, 2015,\1\ the EPA announced that it was strengthening
the primary and secondary NAAQS for ozone to a level of 0.070 parts per
million (ppm).\2\ Since the 2015 primary and secondary NAAQS for ozone
are identical, for convenience, we refer to both as ``the 2015 ozone
NAAQS'' or ``the 2015 ozone standards.'' The 2015 ozone NAAQS retains
the same general form and averaging time as the 0.075 ppm NAAQS set in
2008, but is set at a more protective level.
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    \1\ See 80 FR 65292.
    \2\ Annual fourth highest daily maximum 8-hour average
concentration, averaged over 3 years. For a detailed explanation of
the calculation of the 3-year 8-hour average, see 40 CFR part 50,
Appendix P.
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    The revisions to the ozone NAAQS trigger a process under which
states recommend area designations (i.e., as nonattainment, attainment,
or unclassifiable) to the EPA. The EPA then evaluates air quality data
and other factors prior to making its proposed and final determinations
regarding area designations. To aid the states developing their
recommendations, the EPA issued area designations guidance on February
25, 2016.\3\ Areas designated as nonattainment for the revised ozone
NAAQS will be classified at the time of designation. With this action,
the EPA is proposing and seeking comment on air quality thresholds and
attainment dates for each nonattainment area classification, which it
will finalize upon or before promulgating final area

designations and classifications for the 2015 ozone NAAQS.
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    \3\ The EPA's guidance on the area designations for the 2015
ozone NAAQS is available at https://www.epa.gov/ozone-designations/epa-guidance-area-designations-2015-ozone-naaqs.
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    The Clean Air Act (CAA or Act) does not require that the EPA
promulgate new or revised implementing regulations or guidance every
time that a NAAQS is revised. State, local and tribal air agencies
(hereinafter, referred to simply as air agencies) are required to
submit SIPs as provided in the CAA and in EPA regulations. Where the
nature of revisions to a NAAQS indicate that additional regulations or
guidance (or revisions to existing regulations or guidance) may be
helpful, the EPA endeavors to provide such regulations or guidance to
facilitate the designations process and preparation of timely SIP
submittals. It is important to note, however, that the existing EPA
regulations in 40 CFR part 51 applicable to SIPs generally and to
particular pollutants (e.g., ozone and its precursors) continue to
apply even without such updates. This rule is proposing revisions to
existing regulations and guidance as appropriate to aid in the
implementation of the 2015 ozone NAAQS.
    The EPA believes that the overall framework and policy approach of
the implementation provisions associated with the 2008 ozone NAAQS
provide an effective and appropriate template for the general approach
air agencies should follow in planning for attainment of the revised
ozone standards. However, to assist with the implementation of the
revised ozone standards, the EPA is proposing this additional ozone
NAAQS implementation rule.
    We are proposing multiple actions in this rule pertaining to
nonattainment area classification thresholds and associated attainment
dates, as well as submittal deadlines and specific CAA requirements for
the content of nonattainment area and Ozone Transport Region (OTR) SIPs
for the 2015 ozone NAAQS. As a general matter, this proposed rule
follows the same basic principles and approach that the EPA applied to
interpret the CAA's part D, subpart 2 ozone nonattainment area
requirements in developing the classification and implementation rules
for the 2008 ozone NAAQS.\4\ Additionally, we are proposing and seeking
comment on two alternative approaches for revoking the 2008 ozone NAAQS
and, where applicable, establishing anti-backsliding requirements for
areas that are designated nonattainment at the time the 2008 ozone
NAAQS is revoked.
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    \4\ See the Classifications Rule (77 FR 30160; May 21, 2012) and
SIP Requirements Rule (80 FR 12264; March 6, 2015) for the 2008
ozone NAAQS.
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    Regarding the format of this preamble, we organize our discussion
of implementation requirements for the 2015 ozone NAAQS around the
implementing regulations for the 2008 ozone NAAQS. As stated
previously, we propose to retain without significant revision the
majority of those existing regulations to implement the 2015 ozone
NAAQS, as discussed in Section III of this preamble. We discuss the
existing implementing regulations that we propose to retain with
specific revisions for implementing the 2015 ozone NAAQS in Section IV
of this preamble. For topics where we do not propose any action, we
provide guidance on that topic in the preamble. Section V of this
preamble addresses several requirements and policies not covered by
this proposed rulemaking (with one exception), but for which the EPA is
soliciting public comment (e.g., dealing with emissions from wildfires
and wildland prescribed fires, and international transport and
background ozone).

III. Provisions of the 2008 Ozone NAAQS Implementing Regulations To Be
Retained Without Significant Revision

    For purposes of the 2015 ozone NAAQS, we are proposing to retain
the majority of existing implementation provisions for the 2008 ozone
NAAQS without significant revision. The existing classification and SIP
requirement provisions for the 2008 standards are codified at subpart
AA of 40 CFR part 51, and the corresponding provisions for the 2015
standards would be codified at the new subpart CC of part 51. As
discussed earlier, the EPA believes that the implementing regulations
for the 2008 standards generally provide an appropriate approach to
follow in attainment planning for the 2015 standards, and we welcome
comment on the following proposed provisions.

A. Submitting Nonattainment Area and OTR SIP Elements Due Under CAA
Sections 182 and 184 for the 2015 Ozone NAAQS

1. Deadlines for Submitting Nonattainment Area and OTR SIP Elements
    The EPA is proposing to retain the existing approach to calculating
deadlines for submitting nonattainment SIP elements. Section 182 of the
CAA requires states with ozone nonattainment areas to submit various
SIP elements within specified time periods after enactment of the CAA
Amendments of 1990. For the 2008 ozone NAAQS, the EPA adopted the
approach that the SIP elements listed in the proposal are due based on
the timeframes provided in CAA section 182 as measured from the
effective date of designation, instead of the 1990 date. For reference,
the final 2008 Ozone NAAQS SIP Requirements Rule (2008 ozone SRR)
provides an extensive discussion of the EPA's current approach and
rationale for SIP element submittal deadlines (80 FR 12265; March 6,
2015). The EPA is proposing to retain the same approach for calculating
deadlines for submitting nonattainment area SIP elements under CAA
section 182 for the 2015 ozone NAAQS, based on the current approach and
rationale articulated in the final 2008 Ozone NAAQS SIP Requirements
Rule.
    Accordingly, states with areas designated nonattainment have 2
years from the effective date of nonattainment designation to submit
SIP revisions addressing emission inventories (required by CAA section
182(a)(1)), RACT (CAA section 182(b)(2)) and emissions statement
regulations \5\ (CAA section 182(a)(3)(B)); 3 years to submit SIP
revisions addressing 15 percent rate of progress (ROP) plans (CAA
section 182(b)(1)) and Moderate area attainment demonstrations (CAA
section 182(b)(1)); and 4 years to submit SIP revisions addressing 3
percent per year \6\ RFP plans (CAA section 182(c)(2)) and attainment
demonstrations (CAA section 182(c)(2)) for Serious and higher areas,
where applicable. If an area is subject to vehicle inspection and
maintenance (I/M) program requirements based on its classification, the
SIP revision due date, codified in 40 CFR 51.372(b)(2), would be
aligned with the due date for the attainment demonstration SIP for the
area. The SIP revisions addressing CAA section 185 penalty fee programs
in areas initially classified Severe or Extreme would be due 10 years
from the effective date of designations. Finally, SIP submissions
addressing nonattainment NSR would be due 3 years \7\ from the
effective date of designations.
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    \5\ See Section IV.G of this preamble for additional information
on emissions statements.
    \6\ 3 percent per year RFP plans are typically submitted in 3-
year increments, thus, as 9 percent RFP plans that produce average
reductions of 3 percent per year.
    \7\ See 70 FR 71612, 71672 and 71683 (November 29, 2005); and 80
FR 12264, 12266 and 12267, March 6, 2015.
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    We note also that the EPA's implementing regulations for revised
ozone NAAQS have required OTR states

to submit RACT SIP revisions based on the timeframe provided in CAA
section 184 as measured from the effective date for designations made
pursuant to those revised NAAQS. This requirement was first codified in
40 CFR 51.916 for the 1997 ozone NAAQS, and later codified for the 2008
ozone NAAQS in 40 CFR 51.1116. Under those provisions, states in the
OTR are required to submit SIP revisions addressing the RACT
requirements of CAA section 184 no later than 2 years after the
effective date of designations for the revised ozone NAAQS. The EPA is
proposing to retain these same general requirements for the 2015 ozone
NAAQS (see Section III.L of this preamble).
2. Form and Content of Nonattainment and OTR SIP Element Submissions
Required Under a Revised NAAQS
    The EPA is restating the existing requirement that states must
submit all nonattainment SIP elements applicable for an area's
classification upon revision of the NAAQS, and is providing the
following guidance on the form and content of such submissions. As
discussed in the preceding section, a SIP submission is due from air
agencies for every nonattainment area for each of the SIP elements
listed in this proposal, including (but not limited to) emissions
statement regulations, nonattainment NSR, and vehicle I/M programs,
upon revision of the NAAQS, and they are due based on the timeframes
provided in CAA section 182 as measured from the effective date of
designation.
    The EPA interprets the CAA to require an air agency to provide a
SIP submission to meet each nonattainment area planning requirement for
the 2015 ozone NAAQS. Many air agencies may already have regulations to
address certain requirements in place due to nonattainment designations
for a prior ozone NAAQS. Air agencies should review any existing
regulation that was previously approved by the EPA to determine whether
it is sufficient to fulfill obligations triggered by any revised ozone
NAAQS. In cases where a previously-approved provision is modified for
any reason, or where no provision exists, air agencies must provide the
new or modified provision as a SIP submission. This would include new
or modified RACT provisions for states with nonattainment areas and
states in an OTR, which must be reviewed to ensure that emissions from
affected stationary sources are appropriately controlled. However,
where an air agency believes that an existing regulation is adequate to
meet the nonattainment requirements of CAA section 182 (or OTR RACT
requirements of CAA section 184) for a revised ozone NAAQS, that air
agency's SIP submission may provide a written statement of the
rationale for that determination in lieu of submitting new revised
regulations. For example, a state may have an emissions statement
regulation (per CAA section 182(a)(3)(B)) that has been previously
approved by the EPA for a prior ozone NAAQS that covers all of the
state's nonattainment areas and relevant classes and categories of
sources for the 2015 ozone NAAQS, and is likely to be sufficient for
purposes of the emissions statement requirement for the 2015 ozone
NAAQS. The EPA has taken action on similar written statements. See 80
FR 48036, 48040 (explaining that EPA is approving Georgia's
certification that the state's previously approved regulation meets the
requirements of CAA section 182(a)(3)(B) for the 2008 ozone standards).
Other previously-approved nonattainment SIP elements that may be
sufficient for purposes of an area that has been designated
nonattainment for a revised NAAQS might include (but are not
necessarily limited to): Nonattainment NSR; vehicle I/M programs; and
clean fuels requirement for boilers.
    An air agency choosing to provide a written statement to meet the
submission requirement of the CAA must provide the statement to the EPA
as a SIP submission in accordance with CAA section 110 and 40 CFR
51.102, 103 and Appendix V. An air agency should identify the related
applicable requirements and how each is met for the revised ozone NAAQS
by the regulation previously approved for a prior ozone NAAQS. The
purpose of the statement is to demonstrate compliance with the
nonattainment plan requirements for the new NAAQS. These written
statements must be treated in the same manner as any SIP submission and
must be provided to the EPA in accordance with applicable SIP
submission requirements and deadlines.

B. Applicability of Existing NAAQS Implementation Provisions in 40 CFR
Part 51

    The EPA is proposing to retain its existing general requirement
that establishes the applicability of 40 CFR part 51 to the current and
prior ozone NAAQS. The general applicability of 40 CFR part 51 to the
2008 ozone NAAQS is codified in 40 CFR 51.1101, and requires that the
provisions in subparts A through X of part 51 apply to areas to the
extent they are not inconsistent with the specific implementation
provisions for the 2008 standards (i.e., subpart AA of part 51).
Subparts A through X of part 51 \8\ include generally applicable
requirements for preparation, adoption, and submittal of implementation
plans, as well as specific implementation provisions for the 1997 8-
hour ozone NAAQS (codified in subpart X). The EPA is proposing that the
same requirements apply for purposes of the 2015 ozone NAAQS at 40 CFR
51.1301, except that the listing of potentially applicable subparts
would include the addition of subpart AA of part 51 (i.e., subparts A
through AA).
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    \8\ Excluding subpart Z (Provisions for Implementation of
PM2.5 NAAQS) and subpart BB (Data Requirements for
Characterizing Air Quality for the Primary Sulfur Dioxide
(SO2) NAAQS).
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C. General Classification and Nonattainment Area Planning Provisions

    The EPA is proposing to retain its existing general classification
and nonattainment area planning provisions, which are codified for the
2008 ozone NAAQS in 40 CFR 51.1102. These provisions require that
designated areas be classified in accordance with CAA section 181
(classifications and attainment dates), as interpreted in 40 CFR
51.1103(a), and that designated areas will be subject to the applicable
planning requirements of subpart 2 of part D of title I of the CAA
(additional provisions for ozone nonattainment areas). The EPA is
proposing to retain the same general requirements for the 2015 ozone
NAAQS, without revision, and codify them at 40 CFR 51.1302 and
51.1303(a).

D. Redesignation to Nonattainment Following Initial Designations

    The EPA is proposing to retain its existing requirements for areas
initially designated attainment for the current ozone NAAQS and
subsequently redesignated to nonattainment for the same standards,
which are codified for the 2008 ozone NAAQS in 40 CFR 51.1106. These
provisions generally allow an extension of any absolute, fixed date for
SIP requirements under part 51--excluding attainment dates--equal to
the length of time between the effective date of the initial
designation for the NAAQS and the effective date of redesignation,
unless otherwise provided in the implementation provisions for those
standards. The maximum attainment date for a redesignated area would be
based on the area's classification (see Section IV.A of this preamble
for discussion of classification thresholds and attainment dates). The
EPA is proposing to retain the same requirements for the 2015 ozone
NAAQS, without revision.

E. Determining Eligibility for 1-Year Attainment Date Extensions for
the 2015 Ozone NAAQS Under CAA Section 181(a)(5)

    The EPA is proposing to retain its existing eligibility criteria
for 1-year attainment date extensions under CAA section 181(a)(5),
which are codified for the 2008 ozone NAAQS in 40 CFR 51.1107. An area
that fails to attain a specific ozone NAAQS by its attainment date
would be eligible for the first 1-year extension if, for the attainment
year, the area's fourth highest daily maximum 8-hour average is at or
below the level of the standards. The area would be eligible for the
second 1-year extension if the area's fourth highest daily maximum 8-
hour value, averaged over both the original attainment year and the
first extension year, is at or below the level of the standards. For
the second 1-year extension, the area's fourth highest daily maximum 8-
hour average for each year (the attainment year and the first extension
year) must be determined using the monitor which, for that year, has
the fourth highest daily maximum 8-hour average of all the monitors
that represent that area (i.e., the area's fourth highest daily maximum
8-hour average for each year could be derived from a different monitor)
(see 80 FR 12292; March 6, 2015). The EPA is proposing to retain the
same general eligibility criteria for the 2015 ozone NAAQS, without
revision.
    We are also restating in this preamble that, in addition to
demonstrating that an area meets these general eligibility criteria, an
air agency must demonstrate that it has complied with all requirements
and commitments pertaining to the area in the applicable SIP, per CAA
section 181(a)(5)(A). Given the state and federal partnership in
implementing the CAA, it is reasonable for the EPA to interpret CAA
section 181(a)(5)(A) as permitting the agency to rely upon the
certified statements of its state counterparts, and the EPA has long
interpreted the provision to be satisfied by such statements.\9\ In
practice, in conjunction with a request for an extension, a state air
agency's Executive Officer, or other senior individual with equivalent
responsibilities, signs and affirms that their state is complying with
their applicable federally-approved SIP.
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    \9\ See memorandum signed by D. Kent Berry, Acting Director, Air
Quality Management Division, ``Procedures for Processing Bump Ups
and Extension Requests for Marginal Ozone Nonattainment Areas.''
U.S. EPA, February 3, 1994.
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F. Modeling and Attainment Demonstration Requirements

    The EPA is proposing to retain its existing modeling and attainment
demonstration requirements, which are codified for the 2008 ozone NAAQS
in 40 CFR 51.1108, and to establish criteria and due dates for
attainment demonstrations and implementation of control measures. Due
dates for attainment demonstrations are established relative to the
effective date of area designations, and all control measures in the
attainment demonstration must be implemented no later than the
beginning of the attainment year ozone season, notwithstanding specific
RACT and/or RACM implementation deadline requirements. For reference,
the final 2008 Ozone NAAQS SIP Requirements Rule provides an extensive
discussion of attainment demonstration elements and related modeling
protocols (80 FR 12268; March 6, 2015). The EPA's current procedures
for modeling are well developed and described in the EPA's ``Draft
Modeling Guidance for Demonstrating Attainment of Air Quality Goals for
Ozone, PM2.5, and Regional Haze'' (December 2014).\10\ The
EPA is proposing to retain the same modeling and attainment
demonstration requirements for the 2015 ozone NAAQS, based on the
current approach articulated in the final 2008 Ozone NAAQS SIP
Requirements Rule.
---------------------------------------------------------------------------

    \10\ Modeling guidance, tools, and supporting documents for SIP
attainment demonstration are available at: http://www3.epa.gov/scram001/guidance_sip.htm.
---------------------------------------------------------------------------

G. Requirements for RFP

    The EPA is proposing to retain its existing RFP requirements and to
add new regulatory provisions codifying statutory requirements for RFP
milestone compliance demonstrations (MCDs) (see Section IV.C of this
preamble). The EPA is also seeking comment on requiring states to use
the year of an area's designation as nonattainment as the baseline year
for the emission inventory for the RFP requirement.
    The RFP requirements for the 2008 ozone NAAQS are codified in 40
CFR 51.1110 and require that nonattainment SIPs provide for the annual
incremental emission reductions needed to ensure attainment of the
NAAQS. The provisions in 40 CFR 51.1110 are organized by the following
major subjects: Submission deadline for SIP revisions; RFP requirements
for affected areas; \11\ creditability of emission control measures;
creditability of out-of-area emissions reductions; \12\ calculation of
non-creditable emissions reductions; and baseline emission inventories
for RFP plans. For reference, the final 2008 Ozone NAAQS SIP
Requirements Rule provides an extensive discussion of the EPA's
rationale and approach for how air agencies can provide for RFP in
their nonattainment SIPs (80 FR 12271; March 6, 2015).
---------------------------------------------------------------------------

    \11\ 40 CFR 51.1110(a)(2)-(4) establish three separate sets of
RFP requirements for: (1) Areas with an approved 1-hour or 1997
ozone NAAQS 15 percent VOC rate of progress (ROP) plan; (2) areas
for which an approved 15 percent VOC ROP plan for the 1-hour or 1997
ozone NAAQS exists for only a portion of the area; and (3) areas
without an approved 1-hour or 1997 ozone NAAQS 15 percent VOC ROP
plan.
    \12\ Per 40 CFR 51.1110(a)(6), creditable emission reductions
for fixed percentage reduction RFP must be obtained from sources
within the nonattainment area.
---------------------------------------------------------------------------

    The EPA is proposing to retain the same RFP approach and
requirements for the 2015 ozone NAAQS, except that they would also
apply to areas with approved RFP plans for the 2008 ozone NAAQS, in
addition to the 1-hour and 1997 standards. This proposed approach
includes continuing to state that the baseline year for RFP should be
the calendar year for the most recently available triennial emission
inventory at the time ROP/RFP plans are developed (e.g., 2017 for
initial designations effective in 2018), but states may elect an
earlier alternate year to be used to recognize investments in
implementing early reductions to achieve improved air quality. We
propose that states may use an alternate year (i.e., other that 2017)
between the year of the revised NAAQS issuance (2015) and the year in
which nonattainment designation is effective. However, the EPA is
inviting comment on an alternate approach of requiring that states use
the year of the effective date of an area's designation as the baseline
year for the emission inventory for the RFP requirements.
    The EPA is proposing to codify our existing interpretation of
statutory requirements for RFP MCD, which would be codified into
specific provisions of the RFP requirements discussed here (see Section
IV.C of this preamble).

H. Requirements for RACT and RACM

1. RACT
    The EPA is proposing to retain its existing general RACT
requirements, and to add new deadline requirements for certain RACT SIP
revisions (see Section IV.D of this preamble). The general RACT
requirements for the 2008 ozone NAAQS, which are codified in 40 CFR
51.1112(a) and (b), address the content and timing of RACT SIP

submittals and implementation, and major source criteria for RACT
applicability.\13\ Underlying these general RACT requirements are well-
established EPA policies and guidance, including existing control
techniques guidelines (CTGs) and alternative control techniques
(ACTs).\14\ For reference, the final 2008 Ozone NAAQS SIP Requirements
Rule provides an extensive discussion of the EPA's current rationale
and approach for how air agencies can provide for RACT in their
nonattainment SIPs (80 FR 12278; March 6, 2015). With the exception of
new implementation deadlines for certain RACT SIP revisions (see
Section IV.D of this preamble), the EPA is proposing to retain the same
RACT requirements for the 2015 ozone NAAQS, based on the current
rationale and approach articulated in the final 2008 Ozone NAAQS SIP
Requirements Rule (80 FR 12278; March 6, 2015).
---------------------------------------------------------------------------

    \13\ The EPA has defined RACT as the lowest emission limitation
that a particular source is capable of meeting by the application of
control technology that is reasonably available considering
technological and economic feasibility (December 9, 1976, memorandum
from Roger Strelow, Assistant Administrator for Air and Waste
Management, to Regional Administrators, ``Guidance for Determining
Acceptability of SIP Regulations in Non-Attainment Areas'' and also
in 44 FR 53762; September 17, 1979). Availability and feasibility
may differ across sources in the same category (June 19, 1985,
memorandum from John Calcagni, Chief, Economic Analysis Branch, to
G.T. Helms, ``Criteria for Determining RACT in Region IV.'').
    \14\ The EPA's CTGs and ACTs are available at: https://www3.epa.gov/airtoxics/ctg_act.html.
---------------------------------------------------------------------------

2. RACM
    The EPA is proposing to retain its existing RACM requirements, and
to clarify the requirement under CAA section 172(c)(6) that air
agencies also consider the impacts of emissions from sources outside an
ozone nonattainment area but within a state's boundaries, and to
require such other measures for emissions reductions from these
intrastate sources if needed to attain the ozone NAAQS by the
applicable attainment date (see Section IV.E of this preamble). The
general RACM requirements for the 2008 ozone NAAQS are codified in 40
CFR 51.1112(c). For reference, the final 2008 Ozone NAAQS SIP
Requirements Rule describes the EPA's current rationale and approach
for how air agencies can provide for RACM in their nonattainment SIPs
(80 FR 12282; March 6, 2015). The EPA interprets the RACM provision to
require a demonstration that an air agency has adopted all reasonable
measures (including RACT) to meet RFP requirements and to demonstrate
attainment as expeditiously as practicable and, thus, that no
additional measures that are reasonably available will advance the
attainment date or contribute to RFP for the area.15 16 17
As the EPA has previously stated in the final 2008 Ozone NAAQS SIP
Requirements Rule,\18\ in determining the attainment date that is as
expeditious as practicable, an air agency should consider impacts on
the nonattainment area of intrastate transport of pollution from
sources within its jurisdiction, and potential reasonable measures to
reduce emissions from those sources. Further, the EPA requires that air
agencies should consider all available measures, including those being
implemented in other areas, but must adopt measures for an area only if
those measures are economically and technologically feasible and will
advance the attainment date or are necessary for RFP. The EPA is
proposing to retain its existing general RACM requirements for the 2015
ozone NAAQS--including the requirement to consider measures that
address intrastate transport--based on the current rationale and
approach articulated in the final 2008 Ozone NAAQS SIP Requirements
Rule, and the requirements of CAA section 172(c)(6).
---------------------------------------------------------------------------

    \15\ ``State Implementation Plans; General Preamble for Proposed
Rulemaking on Approval of Plan Revisions for Nonattainment Areas''
44 FR 20375 (April 4, 1979). ``State Implementation Plans; General
Preamble for the Implementation of Title I of the Clean Air Act
Amendments of 1990; Proposed Rule.'' 57 FR 13560 (April 16, 1992).
    \16\ ``Guidance on the Reasonably Available Control Measures
(RACM) Requirement and Attainment Demonstration Submissions for
Ozone Nonattainment Areas.'' John S. Seitz, Director, Office of Air
Quality Planning and Standards. November 30, 1999. Available at:
http://www3.epa.gov/ttn/caaa/t1/memoranda/revracm.pdf.
    \17\ Memorandum of December 14, 2000, from John S. Seitz,
Director, Office of Air Quality Planning and Standards, re:
``Additional Submission on RACM from States with Severe One-Hour
Ozone Nonattainment Area SIPs.'' Available at: http://www3.epa.gov/ttn/caaa/t1/memoranda/121400_racmmemfin.pdf.
    \18\ See the final SIP Requirements Rule for the 2008 ozone
NAAQS (80 FR 12264, 12270; March 6, 2015).
---------------------------------------------------------------------------

    The final 2008 Ozone NAAQS SIP Requirements Rule also recommended
that if wildfire impacts are significant in an area and contribute to
exceedances of the standard, then air agencies should consider RACM for
wildfires (which could include the use of prescribed fires). As
discussed in Section V.A of this preamble, the EPA is revising its
recommendation, such that prescribed fire and related wildland
management practices instead be addressed outside of the regulatory
framework of nonattainment planning.

I. CAA Section 182(f) NOX Exemption Provisions

    The EPA is proposing to retain its existing CAA section 182(f)
NOX exemption provisions, which are codified for the 2008
ozone NAAQS in 40 CFR 51.1113. These provisions allow a person or an
air agency to petition the Administrator for an exemption from
NOX obligations under CAA section 182(f) for any area
designated nonattainment for the 2008 ozone standards and for any area
in a CAA section 184 OTR. 40 CFR 51.1113(c) stipulates that
NOX exemptions granted for previous 1-hour or 1997 ozone
NAAQS do not relieve an area from CAA section 182(f) NOX
obligations under the 2008 standards (see 80 FR 12294; March 6, 2015).
The EPA is proposing to retain the same requirements for the 2015 ozone
NAAQS, stipulating that NOX exemptions granted for any prior
ozone NAAQS do not relieve an area from CAA section 182(f)
NOX obligations under a specific revised ozone NAAQS.
Consistent with current EPA policy, existing NOX waivers for
the 2008 ozone standards would remain valid until area designations for
the 2015 NAAQS become effective, and we encourage air agencies to
consult the EPA's guidance on appropriate documentation for new waiver
requests.\19\
---------------------------------------------------------------------------

    \19\ Memorandum dated January 14, 2005, ``Guidance on Limiting
Nitrogen Oxides (NOX) Requirements Related to 8-Hour
Ozone Implementation'' from Stephen D. Page, Director, Office of Air
Quality Planning and Standards, to Air Directors, Regions I-X.
Available at: http://www3.epa.gov/ttn/caaa/t1/memoranda/guide8hr-oz.pdf.
---------------------------------------------------------------------------

J. General Nonattainment NSR Requirements

    With one significant exception, the EPA is proposing to retain its
NNSR requirements contained at 40 CFR 51.165 and part 51 Appendix S,
which contain provisions for the preconstruction review and issuance of
permits to proposed new major stationary sources and major
modifications locating in ozone nonattainment areas. The one exception
pertains to a proposal to address IPT for ozone. As explained in
Section IV.F of this preamble, the EPA is proposing to confirm its
policy on ozone IPT, which is currently codified at 40 CFR
51.165(a)(11) and part 51 Appendix S, section IV.G.5, in response to a
petition for reconsideration. A basic understanding about how the NNSR
requirements would otherwise apply to the 2015 ozone NAAQS can be
obtained from the preamble discussion at Section VIII.C in the final
rule for the setting of

the 2015 Ozone NAAQS. See 80 FR 65442 (October 26, 2015).
    The EPA proposes to codify NNSR requirements for the ozone NAAQS at
40 CFR 51.1314. These provisions would require that for each
nonattainment area an air agency must submit an NNSR plan or plan
revision for the 2015 ozone NAAQS no later than 36 months after the
effective date of the area's nonattainment designation for the 2015
ozone NAAQS. As discussed in Section IV.B of this preamble, we are
proposing two options for revoking the 2008 ozone NAAQS. The first
approach to revoking the 2008 ozone NAAQS (option 1) would parallel the
approach used in revoking the 1-hour and 1997 ozone NAAQS, and would
require that a set of protective anti-backsliding requirements be
promulgated for all areas that are designated nonattainment for both
the 2008 NAAQS and the 2015 NAAQS. Under the second approach (option
2), the 2008 ozone NAAQS would not be revoked in any area designated
nonattainment for the 2008 ozone NAAQS until that area is redesignated
to attainment with an approved CAA section 175A 10-year maintenance
plan; but in no case earlier than 1 year after the effective date of
designation for the 2015 ozone NAAQS. If the EPA were to revoke the
2008 ozone NAAQS according to proposed option 1, the EPA is also
proposing conforming changes to the existing anti-backsliding
provisions at 40 CFR 51.165(a)(12) and part 51 Appendix S section VII.
See Section IV.B of this preamble for a discussion of the conforming
revisions to the anti-backsliding provisions addressing the proposed
revocation of the 2008 ozone NAAQS under option 1.

K. Ambient Monitoring Requirements

    The EPA is not proposing any changes to the existing ozone ambient
monitoring requirements are codified in 40 CFR part 58. Monitoring rule
amendments published on October 17, 2006, (71 FR 61236) established
minimum ozone monitoring requirements based on population and levels of
ozone in an area to better prioritize monitoring resources. The minimum
monitoring requirements are contained in Table D-2 of appendix D to
part 58. The Photochemical Assessment Monitoring Station (PAMS)
program, required by CAA section 182(c)(1), collects enhanced ambient
air measurements. The rulemaking for the final 2015 ozone NAAQS
included revisions to the PAMS requirements (80 FR 65416; October 26,
2015). The revisions were intended to provide a more spatially
dispersed network, reduce potential redundancy, and improve data value
while providing monitoring agencies flexibility in collecting
additional information needed to understand their specific ozone
issues.

L. Requirements for an OTR

    The EPA is proposing to retain its existing OTR requirements, and
to add new deadline requirements for certain RACT SIP revisions (see
Section IV.D of this preamble). The OTR requirements for the 2008 ozone
NAAQS, which are codified in 40 CFR 51.1116, establish the general
applicability of CAA sections 176A (interstate transport commissions)
and 184 (control of interstate ozone air pollution), and stipulate the
criteria and timing for RACT SIP submittals and RACT implementation for
those portions of states located in an OTR (see 80 FR 12295; March 6,
2015). With the exception of additional submission and implementation
deadlines for certain RACT SIP revisions (see Section IV.D of this
preamble), the EPA is proposing to retain the same requirements for the
2015 ozone NAAQS, without revision.

M. Fee Programs for Severe and Extreme Nonattainment Areas That Fail To
Attain

    The EPA is proposing to retain its existing fee program SIP
submission requirements, which are codified for the 2008 ozone NAAQS in
40 CFR 51.1117, and apply to each area classified Severe or Extreme for
that standard. Affected areas must submit a SIP revision that meets the
requirements of CAA section 185 (Enforcement for Severe and Extreme
ozone nonattainment areas for failure to attain) within 10 years of the
effective date of designation and classification as a Severe or Extreme
area. The EPA is proposing to retain the same SIP submission
requirements for the 2015 ozone NAAQS, without revision.

N. Applicability

    The EPA is proposing to retain the provision that establishes
applicability of the current ozone NAAQS implementation provisions,
which is codified for the 2008 ozone NAAQS in 40 CFR 51.1119. The
provision states that the current provisions (subpart AA of part 51)
shall replace those for the previous 1997 standards (subpart X of part
51) after revocation of the 1997 NAAQS, except for anti-backsliding
purposes. The EPA is proposing to retain the same requirements for the
2015 ozone NAAQS, except that the proposed new implementation
provisions (to be codified in the new subpart CC of part 51) would
replace those for the 2008 ozone NAAQS (subpart AA) if the 2008
standards are revoked for all purposes, except for anti-backsliding
purposes. The proposed revocation of, and anti-backsliding requirements
for, the 2008 ozone NAAQS are discussed in Section IV.B of this
preamble.

IV. Provisions of the 2008 Ozone NAAQS Implementing Regulations To Be
Retained With Specific Revisions

    For purposes of the 2015 ozone NAAQS, we are proposing to
promulgate some provisions that are similar to those for the 2008 ozone
NAAQS, but with minor modifications to reflect application to the 2015
ozone NAAQS, as explained later. The existing classification and SIP
requirement provisions for the 2008 standards, and revocation of the
1997 standards are codified at subpart AA of 40 CFR part 51, and the
corresponding provisions for the 2015 standards would be codified at
the new subpart CC of part 51. These proposed revisions reflect
classification thresholds and attainment deadlines relevant to the 2015
ozone standards; MCD for RFP; submission and implementation deadlines
for RACT SIP revisions; the consideration of intrastate pollution
sources outside of a nonattainment area for attainment planning; NNSR
IPT for ozone; emissions inventories and emissions statements; and
revoking the 2008 standards. The EPA welcomes comment on the following
proposed provisions.

A. Application of Classification and Attainment Date Provisions in CAA
Section 181 to Areas Subject to Subpart 2 of Part D of Title I of the
CAA

1. Background and Summary of Proposal
    The EPA is proposing thresholds for classifying nonattainment areas
for the 2015 ozone NAAQS, and is proposing the timing of attainment
dates for each classification. We are also proposing to grant voluntary
reclassification to six California areas designated as nonattainment
for the 1997 ozone NAAQS that were voluntarily reclassified under that
NAAQS and the subsequent 2008 ozone standards. Each area designated as
nonattainment for the 2015 ozone NAAQS will be classified at the same
time as the area is designated by the EPA. Accordingly, the EPA intends
to finalize classification thresholds on or before the date that it
issues area designations.

2. Initial Area Designations for the 2015 Ozone NAAQS
    After promulgating a new or revised NAAQS, the EPA considers air
agencies' recommendations for initial area designations (i.e., as
nonattainment, attainment, or unclassifiable). Area designations
establish which areas are meeting the NAAQS (attainment) and which
areas are not meeting the NAAQS (nonattainment), and the boundaries for
those areas. Areas designated unclassifiable cannot be classified as
meeting or not meeting the NAAQS based on available information. Based
on the schedule provided in section 107(d) of the CAA, states are
required to submit designation recommendations for every area in the
state to the EPA by no later than October 1, 2016, which is 1 year
after the promulgation date of the 2015 ozone NAAQS.\20\ In the event
that the EPA intends to modify an air agency's recommendation, the EPA
will notify the air agency no less than 120 days prior to issuing
designations.\21\ The CAA requires the EPA to promulgate designations
no later than 2 years after the October 1, 2015, promulgation of the
revised ozone NAAQS. Such period may be extended for up to one year in
the event the Administrator has insufficient information to promulgate
the designations.
---------------------------------------------------------------------------

    \20\ Area designations guidance for the 2015 ozone NAAQS
available at: https://www.epa.gov/ozone-designations/epa-guidance-area-designations-2015-ozone-naaqs.
    \21\ While CAA section 107, which governs the process for
initial area designations, specifically addresses states, the EPA
intends to follow the same process for tribes to the extent
practicable, pursuant to section 301(d) of the CAA regarding tribal
authority and the Tribal Authority Rule (TAR) (63 FR 7254; February
12, 1998).
---------------------------------------------------------------------------

3. Nonattainment Area Classifications
    In accordance with CAA section 181(a)(1), each area designated as
nonattainment for the 2015 ozone NAAQS will be classified at the time
of designation. The planning and emission reduction requirements as
well as the maximum attainment date for each area are based on that
area's classification.
    Under Subpart 2 of part D of title I of the CAA, state planning and
emissions control requirements for ozone are determined, in part, by a
nonattainment area's classification. These requirements apply in
addition to the general SIP planning requirements applicable to all
nonattainment areas under subpart 1 of part D. Under CAA subpart 2,
ozone nonattainment areas are classified based on the severity of their
ozone levels (as determined based on the area's ``design value,''
(DV)).\22\ Nonattainment areas with a ``lower'' classification have
ozone levels that are closer to the standard than areas with a
``higher'' classification. Subpart 2 provides an increasing amount of
maximum time from the date of designation to attain the standards for
the progressively higher classifications: Marginal (3 years), Moderate
(6 years), Serious (9 years), Severe-15 (15 years), Severe-17 (17
years) and Extreme (20 years).
---------------------------------------------------------------------------

    \22\ The air quality DV for the 8-hour ozone NAAQS is the 3-year
average of the annual fourth highest daily maximum 8-hour average
ozone concentration for a specific monitor. When an area has
multiple monitors, the area's DV is determined by the individual
monitor with the highest DV.
---------------------------------------------------------------------------

    Air agencies with areas in the lower classification levels have
fewer mandatory air quality planning and control requirements than
those in higher classifications. For instance, air agencies with a
Marginal area are only required to adopt an emissions statement rule
for major stationary sources, submit a base year emissions inventory,
follow the general and transportation conformity requirements in CAA
section 176(c), and implement a nonattainment area preconstruction
permit program (NNSR). Air agencies with a Moderate area are subject to
the Marginal area requirements; in addition air agencies must submit a
SIP revision that provides for a 15 percent emissions reduction from
the RFP baseline year within 6 years after the baseline year, and a
demonstration that the area will attain as expeditiously as
practicable, but not later than 6 years after designation. Air agencies
with a Moderate area must also adopt (and submit for EPA approval)
certain emissions control requirements, such as RACT, a basic vehicle
I/M program if the area meets the applicable population thresholds, and
provisions for increased offsets for new or modified sources under the
state's NNSR program. The higher classifications similarly require
additional emissions control programs and stricter NNSR requirements
beyond those required for a Moderate area. In addition, the major
source threshold for permitting, RACT and emissions reporting decreases
progressively from 100 tons per year (tpy) for Marginal areas to 10 tpy
for Extreme areas.

4. Proposed Classification Thresholds

    a. Background. The CAA was amended in 1990 to add specific
provisions that apply to ozone nonattainment areas. These include
timelines for both planning and implementation, and requirements for
specific programs to reduce emissions that vary based on an area's
classification. The ozone standard in effect at the time of the 1990
CAA amendments was a 1-hour exceedance-based standard of 0.12 ppm.\23\
Accordingly, the classification provisions in Table 1 in section 181 of
subpart 2 of the CAA (also referred to herein as the ``subpart 2
classification table'') are specific to that 1-hour standard. In 1997,
the EPA revised both the form and level of the ozone NAAQS to a 3-year
average of annual fourth highest daily maximum 8-hour averages.\24\ In
a subsequent rulemaking, the EPA adapted the CAA's 1-hour
classification thresholds to the new 8-hour standard \25\ and used the
new 8-hour threshold values to classify certain areas designated
nonattainment for the 1997 8-hour NAAQS. We translated the
classification thresholds in the subpart 2 classification table from 1-
hour DVs to 8-hour DVs based on the percentage by which each
classification threshold in the table exceeds the 1-hour ozone NAAQS.
We noted that these percentages, as established by Congress in 1990,
set the classification thresholds at certain percentages or fractions
above the level of the standard.\26\ The EPA refers to this method as
the ``percent-above-the-standard'' method. This approach for
translating the CAA's 1-hour threshold values to 8-hour threshold
values was challenged in litigation and was upheld by the Court. See
South Coast Air Quality Management District v. Environmental Protection
Agency, 472 F.3d at 896-898. After analyzing various alternative
options for establishing classification thresholds, the EPA retained
the ``percent-above-the-standard'' approach in its final implementing
regulations for the 2008 ozone NAAQS.\27\
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    \23\ For additional discussion on the 1-hour ozone NAAQS and its
associated area designations and classifications, see 56 FR 56695
(November 6, 1991).
    \24\ See 40 CFR Appendix I.
    \25\ Referred to as the Phase 1 Rule, see 69 FR 23956 to 23966
and part 51, subpart X at 51.903.
    \26\ The upper thresholds of the Marginal, Moderate, Serious and
Severe classifications are precise percentages or fractions above
the level of the standard, namely 15 percent (3/20ths more than the
standard), 33.33 percent (one-third more than the standard), 50
percent (one-half more than the standard), and 133.3 percent (one
and one-third more than the standard).
    \27\ See 77 FR 30162 to 30164 (May 21, 2012).
---------------------------------------------------------------------------

    b. Proposed classification threshold method. In this action, we are
proposing to use the same ``percent-above-the-standard'' methodology as
was used for establishing thresholds for classifications for the 1997
and 2008 8-hour ozone standards. The percent-above-the-standard method
is a simple and straightforward method for establishing classification
thresholds that is based on principles inherent in

the subpart 2 classification table itself. The principles include the
following:
     Areas are grouped by the severity of their air quality
problem as characterized by the degree of nonattainment based on their
DV.
     Classification would occur ``by operation of law'' without
relying on the EPA exercising discretion for individual situations.\28\
---------------------------------------------------------------------------

    \28\ Prior to any application of the 5 percent adjustment
provision under CAA section 181(a)(4) which may occur in the 90-day
period following initial designations and classifications). See
Section IV.A.5 of this preamble for details on how the EPA proposes
to interpret previous voluntary reclassification requests for the
1997 ozone NAAQS under the 2015 ozone NAAQS.
---------------------------------------------------------------------------

     Classification thresholds are derived from the structure
or logic of the CAA's nonattainment area planning and control
requirements, including the subpart 2 classification table, and
consistent with the overall goal of subpart 2 of attaining the
standards as expeditiously as practicable. At the same time, the CAA
provides mechanisms for voluntary and mandatory reclassification to a
higher classification, in the event that the initial maximum attainment
date for an area is determined to be insufficient to achieve the
standards.
    In developing its proposed Classifications Rule for the 2008 ozone
standards, the EPA evaluated other options for classifying ozone
nonattainment areas but did not find them to be a more reasonable
interpretation of the Act's classification provisions, and did not
propose or solicit comment on them in the rule.\29\
---------------------------------------------------------------------------

    \29\ Docket #EPA-HQ-OAR-2010-0885 includes a background
information document prepared for the proposed rule titled,
Additional Options Considered for Classification of Nonattainment
Areas under the Proposed 2008 Ozone NAAQS (January 2012).
---------------------------------------------------------------------------

    Under the proposed percent-above-the-standard method, the
classification thresholds in the subpart 2 classification table would
be translated into a corresponding set of 8-hour DVs that are the same
percentages above the 2015 ozone NAAQS as the DV levels in the subpart
2 classification table are above the 1-hour ozone NAAQS. For example,
the threshold separating the Marginal and Moderate classifications in
the subpart 2 classification table (0.138 ppm) is 15 percent above the
1-hour ozone NAAQS (0.12 ppm). Thus, under this approach, the threshold
separating the Marginal and Moderate classifications for the 2015 ozone
NAAQS would be 0.070 ppm plus 15 percent, or 0.081 ppm. Table 1 depicts
this proposed translation for classifications as it would apply for the
2015 ozone NAAQS.

  Table 1--Subpart 2 1-Hour Ozone Design Value Classification Table Translation to 8-Hour Design Values for the
                                          2015 Ozone NAAQS of 0.070 PPM
----------------------------------------------------------------------------------------------------------------
                                                                                Percent above 1-   8-hour ozone
             Area class                                         1-Hour design      hour ozone      design value
                                                                 value (ppm)         NAAQS            (ppm)
----------------------------------------------------------------------------------------------------------------
Marginal............................  From up to \a\.........            0.121            0.833            0.071
                                                                         0.138               15            0.081
Moderate............................  From up to \a\.........            0.138               15            0.081
                                                                         0.160           33.333            0.093
Serious.............................  From up to \a\.........            0.160           33.333            0.093
                                                                         0.180               50            0.105
Severe-15...........................  From up to \a\.........            0.180               50            0.105
                                                                         0.190           58.333            0.111
Severe-17...........................  From up to \a\.........            .0190           58.333            0.111
                                                                         0.280          133.333            0.163
Extreme.............................  Equal to or above......            0.280          133.333            0.163
----------------------------------------------------------------------------------------------------------------
\a\ But not including.

    Based on our analysis of air quality information from 2013-2015, we
estimate that approximately 57 ``hypothetical nonattainment areas'' had
ambient ozone concentrations exceeding the 2015 ozone NAAQS. We use
these 57 ``hypothetical nonattainment areas'' for purposes of the
following discussion. These hypothetical areas are intended to
illustrate the potential distribution of areas into the proposed
classifications. The actual number of total nonattainment areas,
boundaries of those areas, and the classification of each area will
depend on decisions made in the separate designations process under CAA
section 107(d) and we anticipate that these decisions will be based on
air quality information from 2014-2016. Applying the proposed
thresholds in Table 1, the 57 hypothetical nonattainment areas based on
2013-2015 air quality data would yield the distribution in each
classification as shown in Table 2.

       Table 2--Number of Hypothetical Nonattainment Areas in Each
  Classification Under the 2015 Ozone NAAQS: Percent-Above-the-Standard
                                 Method
------------------------------------------------------------------------
                                                            2015 Ozone
                                                               NAAQS
                   Area classification                     (hypothetical
                                                            areas) \a\
------------------------------------------------------------------------
Marginal................................................              47
Moderate................................................               7
Serious.................................................               3
Severe-15...............................................               0
Severe-17...............................................               0
Extreme.................................................               0
                                                         ---------------
    Total...............................................              57
------------------------------------------------------------------------
\a\ Hypothetical nonattainment area classifications do not reflect
  potential voluntary reclassifications of the California areas
  discussed in Section IV.A.5 of the preamble.

    The proposed classification method results in the vast majority of
nonattainment areas being classified Marginal. It is possible that a
few areas would have a later maximum statutory attainment date for
their existing classification under the 2008 ozone NAAQS than they
would have for their new classification under the 2015 NAAQS. For
example, an area that would be classified Moderate if designated in
2017 for the more stringent 2015 ozone NAAQS (with a potential maximum
statutory attainment date in 2023), may currently be classified Severe
for the less-stringent 2008 ozone NAAQS (which has a later maximum
statutory attainment date in 2027).\30\ This issue also arose under the
previously promulgated 8-hour classification threshold structure for
the 2008 NAAQS. See Section IV.A.5 of this preamble for additional
details on how the EPA intends to address previous voluntary
reclassifications under the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    \30\ As indicated elsewhere in this preamble, the CAA requires
the EPA to designate areas for the 2015 standard by October 1, 2017.
Thus, a 6-year attainment deadline would be in 2023.
---------------------------------------------------------------------------

    For areas likely to be classified Marginal with a 3-year attainment
date

(e.g., in 2020), a number of federal and state emission reduction
programs have already been adopted that are expected to provide
reductions of ozone precursor emissions, both within and upwind of the
ozone nonattainment areas, lowering peak ozone concentrations by the
attainment date. Such programs include more stringent emission
standards for on-road and nonroad vehicles and equipment (with
associated fleet turnover), regional reductions in power plant
emissions to address interstate transport, and future programs to
reduce VOC emissions from oil and gas sources.
5. Reclassification of Nonattainment Areas That Have Voluntarily
Requested Higher Classifications
    The CAA provides three mechanisms for addressing nonattainment
areas that may not be able to attain by the attainment date appropriate
to their classification. First, CAA section 181(a)(4) provides that
within 90 days of designation and classification, the Administrator may
exercise discretion to reclassify an area to a higher (or lower)
classification if its DV is within 5 percent of the DV range of the
higher (or lower) classification.\31\ Any air agency interested in
taking advantage of this flexibility should submit a request to the EPA
in sufficient time for the Administrator to make a determination within
the 90 days provided.
---------------------------------------------------------------------------

    \31\ Because most areas would be expected to be classified
Marginal (i.e., the lowest classification) and the few areas that
would be classified in higher classifications are likely to be
challenged to attain by the attainment date for the classification
it receives at the time of designation, we do not anticipate
receiving requests to reclassify an area to a lower classification.
---------------------------------------------------------------------------

    The second mechanism, provided in CAA section 181(b)(2), requires
that an area be reclassified to a higher classification (i.e.,
``bumped-up'') if the EPA determines that the area has failed to attain
the standard by the applicable attainment date.
    The third mechanism, provided in CAA section 181(b)(3), allows an
air agency to voluntarily request that the EPA reclassify the area to a
higher classification. The EPA must approve any such requests. Once an
area is reclassified to a higher classification, it becomes subject to
the associated additional planning and control requirements for that
higher classification, and must attain the standard no later than the
maximum attainment date for that classification. Six nonattainment
areas in California were granted voluntary reclassifications for both
the 1997 and 2008 ozone standards (77 FR 30165; May 21, 2012).
    The EPA is again proposing to apply a previous voluntary
reclassification for areas in California to the more stringent 2015
ozone standards unless the state of California explicitly requests
otherwise in their comments to this proposed action.\32\ These areas
are listed in Table 3. We believe this is an appropriate mechanism to
address the situation for these California areas that were voluntarily
reclassified for the 1997 ozone NAAQS and previously used this
mechanism for the 2008 ozone NAAQS to ensure the areas would have an
attainment date for the more stringent 2015 ozone NAAQS that is no
earlier than the area's attainment date for the less stringent 2008
NAAQS. The EPA is proposing this approach in order to minimize burden
on the state of California and obviate the need to go through the
voluntary reclassification process again.
---------------------------------------------------------------------------

    \32\ Areas for which California declines voluntary
reclassification would be classified at the time of designation for
the 2015 ozone NAAQS based on their DV.

                      TABLE 3--Areas for Which the State of California Requested a Voluntary Reclassification Under the 1997 NAAQS
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Hypothetical
                                                               Voluntary              Voluntary              initial             Potential voluntary
                                    Original 1997 ozone   reclassification for   reclassification for     classification     reclassification under 2015
        Nonattainment area         NAAQS classification     1997 ozone NAAQS       2008 ozone NAAQS      under 2015 ozone    ozone NAAQS \a\ (attainment
                                     (attainment date)     (attainment date)      (attainment date)         NAAQS \a\                   date)
                                                                                (attainment date)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Los Angeles-South Coast Air Basin  Severe-17 (2021)....  Extreme (2024).......  Extreme (2032).......  Serious (2026).....  Extreme (2037).
San Joaquin Valley...............  Serious (2013)......  Extreme (2024).......  Extreme (2032).......  Serious (2026).....  Extreme (2037).
Riverside County (Coachella        Serious (2013)......  Severe-15 (2019).....  Severe-15 (2027).....  Moderate (2023)....  Severe-15 (2032).
 Valley).
Sacramento Metro.................  Serious (2013)......  Severe (2019)........  Severe-15 (2027).....  Moderate (2023)....  Severe-15 (2032).
Ventura County...................  Moderate (2010).....  Serious (2013).......  Serious (2021).......  Marginal (2020)....  Serious (2026).
Western Mojave...................  Moderate (2010).....  Severe-15 (2019).....  Severe-15 (2027).....  Moderate (2023)....  Severe-15 (2032).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Based on thresholds proposed in this notice and final 2013-2015 design values.

    It is important to note that an air agency may request a voluntary
reclassification for an area under CAA section 181(b)(3) at any time.
If the air agency wants a specific higher classification to apply to an
area at the time of initial designation, the EPA encourages the air
agency to make such a request prior to or contemporaneous with the
designation process.
6. Attainment Dates for Nonattainment Areas in Each Classification of
the 2015 ozone NAAQS
    The EPA is proposing to retain its current approach in establishing
attainment dates for each nonattainment area classification, which run
from the effective date of designation. This approach is codified at 40
CFR 51.1103 for the 2008 ozone NAAQS, and we are proposing to retain
the same approach for the 2015 ozone NAAQS without revision.
    In the implementing regulations for the 1997 ozone NAAQS, the EPA
interpreted these timeframes to run from the date that area
designations and nonattainment classifications (by operation of law)
became effective (64 FR 23954; April 30, 2004). We adopted an
alternative approach in the classification regulations for the 2008
ozone standards, where the attainment dates would be December 31 of the
year that is the specified number of years in the subpart 2
classification table after designation (77 FR 30166; May 21, 2012). The
end of calendar year attainment date was challenged in NRDC v. EPA, 777
F.3d 456 (D.C. Cir. 2014). On December 23, 2014, the U.S. Court of
Appeals for the District of Columbia Circuit issued an opinion holding
that the EPA's decision to run the attainment periods to the end of the
calendar year in which areas were designated was unreasonable. While

recognizing that there is a ``gap'' in the statute since the CAA runs
the attainment periods from the date of enactment of the CAA Amendments
of 1990, the Court concluded that nothing in the statute or
congressional intent authorized the EPA to establish the attainment
dates for designated ozone nonattainment areas as December 31st of the
relevant calendar years, but rather that Congress's decision to run the
``. . . attainment periods starting from the designation date'' for the
ozone standard existing at the time of the 1990 CAA amendments
``strongly suggests that the same trigger date should apply when
adapting [applicable attainment dates] to the analogous situation of a
revised NAAQS.'' 777 F.3d at 466. The EPA subsequently revised its
regulations for the 2008 ozone NAAQS to follow the same approach used
for the 1997 ozone NAAQS, and this is codified at 40 CFR 51.1103.
    Consistent with the regulatory approach for both the 1997 and 2008
ozone NAAQS, we are proposing that the maximum attainment dates for
nonattainment areas in each classification under the 2015 NAAQS are as
follows: Marginal--3 years from effective date of designation;
Moderate--6 years from effective date of designation; Serious--9 years
from effective date of designation; Severe--15 years (or 17 years) from
effective date of designation; and Extreme--20 years from effective
date of designation.

B. Transition From the 2008 Ozone NAAQS to the 2015 Ozone NAAQS and
Anti-Backsliding Requirements

1. Background and Summary of Proposal
    The EPA is proposing and seeking comment on two alternative
approaches for revoking the 2008 ozone NAAQS and is also seeking
comment on whether to revoke the NAAQS at the current time. The first
approach to revoking the 2008 ozone NAAQS would parallel the approach
used in revoking the 1-hour and 1997 ozone NAAQS. Under this first
approach, the 2008 ozone NAAQS would be revoked at essentially the same
time for all areas of the U.S., and a set of protective anti-
backsliding requirements would be promulgated for all areas that are
designated nonattainment for the 2008 and 2015 NAAQS as of one year
after the effective date of designation for the 2015 ozone NAAQS. Under
the second approach, the 2008 ozone NAAQS would continue to apply in
any area designated nonattainment for the 2008 ozone NAAQS until that
area is redesignated to attainment with an approved CAA section 175A
10-year maintenance plan; but in no case earlier than 1 year after the
effective date of designation for the 2015 ozone NAAQS. The 2008 ozone
NAAQS would be revoked in all other areas 1 year after the effective
date of designation for the 2015 ozone NAAQS.
2. Rationale and Authority
    The EPA believes that both of the proposed options to revoke the
2008 ozone NAAQS are consistent with the CAA and previous precedent in
transitioning from a previous NAAQS to a new, more stringent NAAQS, and
would help ensure that areas designated attainment for the revoked
NAAQS continue to attain the revoked NAAQS into the future.
    a. Option 1: Revoke the 2008 ozone NAAQS for all purposes in each
area 1 year after the effective date of the designation for the 2015
ozone NAAQS. The EPA's first proposed option would revoke the 2008
ozone NAAQS for all purposes 1 year following the effective date of the
designations for the 2015 ozone standard. The EPA interprets the CAA
such that revoking the 2008 ozone NAAQS in an area would require
appropriate anti-backsliding measures. Therefore, the EPA is proposing
that anti-backsliding provisions would apply to an area in accordance
with its designation and its classification for the 2008 (and, if
applicable, 1997 and 1-hour) ozone NAAQS as of the effective date of
the revocation of the 2008 ozone NAAQS (a more detailed discussion of
EPA's proposed approach to anti-backsliding is provided in Section
IV.B.4 of this preamble). Upon revocation of the 2008 NAAQS, the areas
that had been initially designated or subsequently redesignated to
attainment for the 2008 NAAQS prior to its revocation would be subject
only to the general protections of CAA sections 110(l) and 193, whereas
areas designated nonattainment for the 2008 NAAQS would also be subject
to an extensive set of regulatory anti-backsliding provisions
promulgated in accordance with the principles of CAA section 172(e).
This approach is consistent with the EPA's established practice in
transitioning from prior to current ozone NAAQS.
    After revocation of the 2008 ozone NAAQS, the designations (and the
classifications associated with those designations) for that NAAQS
would no longer be in effect. However, the EPA would retain the listing
of the designated nonattainment areas and their associated
classifications for the revoked 2008 ozone NAAQS in 40 CFR part 81, for
the sole purpose of identifying the anti-backsliding requirements that
may apply to the areas at the time of revocation. Accordingly, such
references to historical designations for the revoked NAAQS should not
be viewed as current designations under CAA section 107(d).
    The EPA believes it would be appropriate to revoke, rather than
retain, the 2008 ozone NAAQS for all purposes because it would ensure
that only one ozone NAAQS--in this case the more protective 2015 ozone
NAAQS--would directly apply in an area, rather than having a situation
in which two standards would apply concurrently. The EPA believes that
the permanent retention of two standards, differing only in the ozone
concentrations they allow, could result in unnecessarily complex
implementation procedures \33\ and is not necessary to provide for
timely attainment of the more stringent NAAQS. The EPA's reason for
establishing the new standards of 0.070 ppm as requisite to protect
public health and welfare was its conclusion that the old standard of
0.075 ppm was not adequate. Revoking (with appropriate anti-backsliding
measures) rather than retaining the 2008 ozone NAAQS would facilitate a
more seamless transition to demonstrating compliance with the more
health and welfare protective 2015 ozone NAAQS, and would ensure an
efficient use of state and local resources in working toward attainment
of that standard. Moreover, we believe that by requiring adequate anti-
backsliding measures we will ensure continued momentum in air agencies'
efforts toward achieving clean air.
---------------------------------------------------------------------------

    \33\ For example, if an area's boundaries for two ozone NAAQS
differ from one another the same test of conformity cannot be used
for both ozone NAAQS (see 77 FR 30168; May 21, 2012).
---------------------------------------------------------------------------

    The D.C. Circuit held that the EPA had authority to revoke the one-
hour NAAQS so long as it introduced adequate anti-backsliding measures.
South Coast Air Quality Mgmt. Dist. v. EPA, 472 F.3d 882, 899 (D.C.
Cir. 2006). The EPA is proposing to follow the same approach here as
was upheld by the D.C. Circuit by requiring adequate anti-backsliding
measures, as discussed in this section of the preamble.
    b. Option 2: Revoke the 2008 ozone NAAQS for all purposes in an
area only when designated attainment for that NAAQS, no sooner than 1
year after the effective date of the designations for the 2015 ozone
NAAQS. Under this option, the EPA would not revoke the 2008 ozone NAAQS
in any area that is designated nonattainment for that NAAQS. For areas
designated attainment or unclassifiable for the 2008

NAAQS on the effective date of designations for the 2015 ozone NAAQS,
the 2008 ozone NAAQS would be revoked 1 year after the effective date
of the 2015 NAAQS designation for that area. For nonattainment areas
that are subsequently redesignated attainment (maintenance) for the
2008 ozone NAAQS, the 2008 ozone NAAQS would be revoked upon
designation, but in no case sooner than 1 year after the effective date
of the designation for the 2015 ozone NAAQ for the area. This proposed
approach follows the approach established in revocation of the 1997
primary annual particulate matter (PM2.5) NAAQS (see 81 FR
58142, August 24, 2016). This option is also consistent with the
approach established for the transition from the prior lead and sulfur
dioxide (SO2) NAAQS to the current lead and SO2
NAAQS (see 73 FR 67043, November 12, 2008; and 75 FR 35581, June 22,
2010, respectively).
    Under this proposed approach, areas that are designated
nonattainment for the 2008 ozone NAAQS at the time initial area
designations are completed for the 2015 NAAQS would be required to
continue to meet all applicable implementation requirements for the
2008 NAAQS in those areas, and would continue to seek redesignation to
attainment for the 2008 ozone NAAQS when the areas meet the conditions
necessary for redesignation. While such an area remains designated
nonattainment for the 2008 ozone NAAQS, transportation and general
conformity would continue to apply and the EPA would continue to
reclassify areas as provided in CAA section 181(b)(2). Further, the
designations for the 2008 ozone NAAQS would no longer be in effect in
areas where the NAAQS has been revoked, and the sole designations that
would remain in effect would be those for the 2015 ozone NAAQS.
Transportation and general conformity requirements for the 2008 ozone
NAAQS would no longer apply in the areas where that NAAQS has been
revoked.
    The EPA notes that under proposed option 2, it is unnecessary to
propose a specific set of additional anti-backsliding requirements for
the 2008 ozone NAAQS, since option 2 would only revoke this NAAQS in
areas initially designated or redesignated attainment for the 2008
NAAQS. Special additional anti-backsliding requirements are not
necessary for areas that have attained the 2008 NAAQS. In areas that
have been redesignated to attainment for the 2008 ozone NAAQS while
that NAAQS is in effect, states have fulfilled all applicable
attainment and maintenance plan requirements for that NAAQS, including
applicable anti-backsliding requirements for the prior revoked 1997 and
1-hour ozone NAAQS. The area, therefore, is not subject to any specific
additional anti-backsliding requirements for the revoked 2008 ozone
NAAQS. These areas are required instead to implement their approved CAA
section 175A maintenance plan for the 2008 ozone NAAQS and, if
designated attainment for the 2008 ozone NAAQS implement a Prevention
of Significant Deterioration (PSD) program for this NAAQS. Revisions to
the approved maintenance plan for such an area can only be made subject
to the CAA's provisions in sections 110(l) and 193, which prevent
changes to SIPs if such changes would interfere with attainment and
maintenance of the more current 2015 ozone NAAQS.
3. Effective Date of the Revocation of the 2008 Ozone NAAQS
    Under either option 1 or 2 outlined earlier, the EPA is proposing
to revoke the 2008 ozone NAAQS no sooner than one year after the
effective date of an area's final designation for the 2015 ozone
standards.\34\ The proposed timeline for revocation of the standard
under either option 1 or 2 outlined earlier is intended to ensure that
there is no period during which conformity does not apply in areas that
are nonattainment or maintenance for the 2008 ozone NAAQS and that are
designated nonattainment for the 2015 ozone NAAQS, and that
nonattainment areas for the 2015 ozone NAAQS do not have to perform
transportation conformity analyses for both the prior and current ozone
standards at the same time.\35\ As an example, areas designated
nonattainment for the first time for the 2015 ozone NAAQS would have a
1-year grace period before transportation conformity applies for those
standards. This 1-year grace period before transportation conformity is
required would apply to all areas designated nonattainment for the 2015
standards, regardless of their 2008 NAAQS designation status.
Transportation conformity for the 2008 standards would, therefore, no
longer apply 1 year following the effective date of the 2015 ozone
NAAQS designations (i.e., when the 2008 standards are revoked in
eligible areas). However, transportation conformity obligations for the
2008 ozone standards would remain applicable during the grace period
and would not be affected by the designation of areas for the 2015
NAAQS. Our proposed approach further supports air quality planning in
allowing areas to be redesignated to attainment or reclassified to a
higher classification until the 2008 ozone NAAQS is revoked.
---------------------------------------------------------------------------

    \34\ The 2008 Ozone NAAQS SIP Requirements Rule revoked the 1997
ozone standards upon the effective date of that final rule (April 6,
2015), which was 30 days after its publication in the Federal
Register (80 FR 12296; March 6, 2015). The EPA deemed this approach
appropriate because the final SIP requirements rule was being issued
more than a year after the effective date of final area designations
(July 20, 2012) for the 2008 ozone standards (77 FR 30160; May 21,
2012), an atypical sequence that is not expected to apply in this
case.
    \35\ The EPA believes that these concerns are relevant for
either proposed option 1 or option 2, and therefore proposes the
same timeline for revocation for either option. Under option 2, the
motivation of ensuring that areas do not have to perform
transportation conformity analyses for both the prior and current
ozone standards at the same time would only be relevant for 2015
ozone NAAQS nonattainment areas that are maintenance areas for the
2008 ozone NAAQS at the time of the initial revocation. Areas that
remain designated nonattainment for the 2008 ozone NAAQS at the time
of the initial revocation are required to continue to make
transportation conformity determinations until they are redesignated
to attainment for that NAAQS regardless of their designation status
for the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    If the 2008 ozone NAAQS are revoked in an area in a manner
consistent with the EPA's first proposed option, the anti-backsliding
requirements for those NAAQS would become applicable. The extent of
continued implementation efforts for revoked standards derives from
administration of anti-backsliding requirements (if any) for the
revoked standards. After the 2008 ozone NAAQS is revoked for an area,
the EPA will no longer take action to reclassify or to redesignate that
area for that NAAQS. Further, the designations for the 2008 ozone NAAQS
would be no longer be in effect in such areas, and the sole
designations that would remain in effect would be those for the 2015
ozone NAAQS. However, under option 1, the EPA would retain the listing
of the designated areas and the associated nonattainment
classifications for the revoked 2008 ozone NAAQS in 40 CFR part 81, for
the sole purpose of identifying the anti-backsliding requirements that
may apply to the areas as of the effective date of the revocation. Such
references to historical designations for the revoked standards would
not be current designations under CAA section 107(d) and should not be
viewed as such. If the EPA finalizes the option 2 approach to
revocation of the 2008 ozone NAAQS, the EPA would continue to
redesignate areas for the 2008 ozone NAAQS after the initial revocation
occurs 1 year after the effective date of designations for the 2015
ozone NAAQS. For any area

redesignated more than 1 year after the effective date of designations
for the 2015 ozone NAAQS, the 2008 ozone NAAQS would be revoked on the
effective date of the redesignation to attainment for the 2008 ozone
NAAQS.
4. Anti-Backsliding Requirements
    ``Anti-backsliding'' provisions are designed to ensure that for
existing ozone nonattainment areas that are designated nonattainment
for the revised and more stringent ozone NAAQS, there is protection
against degradation of air quality (e.g., the areas do not
``backslide''), the areas continue to make progress toward attainment
of the new, more stringent NAAQS, and there is consistency with the
ozone NAAQS implementation framework outlined in subpart 2 of Part D of
the CAA.
    Where a NAAQS is relaxed, CAA section 172(e) requires EPA to
promulgate regulations that impose on areas, which have not attained a
NAAQS prior to a relaxation, controls that are at least as stringent as
the controls applicable in nonattainment areas prior to any such
relaxation. Such controls are often referred to as ``anti-backsliding
requirements.'' Because the CAA does not speak to what to do where a
NAAQS is strengthened, the EPA has historically concluded, and proposes
to do so again here, that it is reasonable to look to the principles
set forth in CAA section 172 to impose anti-backsliding requirements
for purposes of transitioning to a more stringent NAAQS. See 69 FR
23951, 23972 (April 30, 2004); 80 FR 12264, 12297-98 (March 6, 2015).
The D.C. Circuit has upheld the EPA's authority to revoke a superseded
NAAQS in its entirety where adequate anti-backsliding measures are
retained under the principles of CAA section 7502(e). South Coast Air
Qual. Mgmt Dist. v. EPA, 472 F.3d 882, 899 (D.C. Cir. 2006).
    Under option 1, the EPA is proposing to retain, for purposes of the
transition from the 2008 to the 2015 ozone NAAQS, the existing approach
to establishing anti-backsliding requirements. The proposed subpart CC,
40 CFR 51.1300 et seq., provides the set of anti-backsliding
requirements that would apply following revocation of the 2008 ozone
NAAQS along with the use of the latest approved or adequate motor
vehicle emission budgets for a prior ozone NAAQS (i.e., the 2008, 1997
or the 1-hour ozone NAAQS) at 40 CFR 93.109(c)(2) as part of
transportation conformity determinations in nonattainment areas for the
2015 NAAQS until 2015 ozone motor vehicle emissions budgets are
available.\36\ For reference, the final 2008 Ozone NAAQS SIP
Requirements Rule provides an extensive discussion of the EPA's
approach and rationale for establishing anti-backsliding requirements
consistent with the first proposed revocation option in this proposal
(option 1) (80 FR 12296-12308; March 6, 2015). The EPA is proposing a
second approach (option 2) to revoking the 2008 ozone NAAQS that would
not require the same extensive set of anti-backsliding requirements.
This co-proposal and associated anti-backsliding approach are discussed
previously in this section of the preamble.
---------------------------------------------------------------------------

    \36\ The EPA believes it is unnecessary to propose to include
the use of existing SIP motor vehicle emissions budgets for
transportation conformity purposes in the proposed list of
regulatory anti-backsliding requirements subpart CC, 40 CFR 51.1300
et seq because EPA's regulations (40 CFR 93.109(c)(2)) already
require that transportation conformity determinations in
nonattainment areas for the new ozone NAAQS continue to be based on
the latest approved or adequate motor vehicle emission budgets for a
prior ozone NAAQS (i.e., the 2008, 1997 or the 1-hour ozone NAAQS)
until 2015 ozone budgets are available.
---------------------------------------------------------------------------

    The following sections discuss the applicable anti-backsliding
requirements and how they apply to areas with various designations and
classifications for the 2015 standards, the 2008 standards that we are
proposing to revoke, and the already revoked 1997 and 1-hour ozone
NAAQS. Our proposed approach for revoking the 2008 ozone NAAQS is
discussed in Section IV.B of this preamble.
    a. Applicable requirements for anti-backsliding purposes following
the revocation of the 2008 ozone NAAQS. As discussed in more detail in
Section IV.B of this preamble, the EPA is proposing and seeking comment
on two options for revoking the 2008 ozone NAAQS. As explained in that
section, under proposed option 2, it is unnecessary to propose specific
new anti-backsliding requirements for the 2008 ozone NAAQS, since
option 2 would only revoke this NAAQS in attainment areas. Therefore,
the following section would only apply if EPA were to finalize option 1
for revocation of the 2008 ozone standard. For purposes of the revoked
2008 ozone NAAQS if option 1 were to be finalized, the EPA is proposing
to retain the same set of anti-backsliding requirements that currently
apply for purposes of the revoked 1997 ozone NAAQS, without revision.
    For the revoked 2008 ozone NAAQS, the potentially applicable
requirements for an area for anti-backsliding purposes would be
identical to the requirements currently codified at 40 CFR 51.1100(o).
These requirements include: (1) RACT; (2) Vehicle I/M programs; (3)
Major source applicability cut-offs for purposes of RACT; (4) ROP and/
or RFP reductions and associated MCDs; (5) the Clean Fuel Fleet program
under section 183(c)(4) of the CAA; (6) Clean fuels for boilers under
section 182(e)(3) of the CAA; (7) Transportation control measures
during heavy traffic hours as provided under section 182(e)(4) of the
CAA; (8) Enhanced (ambient) monitoring under section 182(c)(1) of the
CAA; (9) Transportation controls under section 182(c)(5) of the CAA;
(10) Vehicle miles traveled provisions under section 182(d)(1)(A) of
the CAA; (11) NOX requirements under section 182(f) of the
CAA; (12) Attainment demonstrations; (13) Nonattainment contingency
measures; (14) Nonattainment NSR major source thresholds and offset
ratios; (15) CAA section 185 requirements for Severe and Extreme areas
for failure to attain; (16) RACM; and (17) Contingency measures for
SIPs invoking section 182(e)(5) of the CAA. The use of the latest
approved or adequate motor vehicle emission budgets for a prior ozone
NAAQS (i.e., the 2008, 1997 or the 1-hour ozone NAAQS) as part of
transportation conformity determinations in nonattainment areas for the
2015 NAAQS until 2015 ozone motor vehicle emissions budgets are
available has also been recognized as a ``control'' for purposes of
defining anti-backsliding requirements. South Coast Air Qual. Mgmt.
Dist. v. EPA, 489 F.3d at 1248 (clarifying South Coast, 472 F.3d at
904-05). This requirement is already codified at 40 CFR 93.109(c)(2).
As discussed in the following section, applicability of individual
anti-backsliding requirements for an area would depend on its
designation and classification for all three of the revoked standards.
    b. Transition requirements for nonattainment and attainment areas.
The EPA is proposing to retain its current approach for applying
transition requirements to various categories of nonattainment and
attainment areas. This approach is codified at 40 CFR 51.1105, and we
are proposing to retain the same approach adopted through the 2008
Ozone NAAQS SIP Requirements Rule in this rulemaking at 40 CFR 51.1305,
revised to address the revocation of the 2008 ozone NAAQS in addition
to the other prior revoked standards.
    Table 4 provides a summary of the four transition categories, and
the proposed requirements that would apply for each of those
categories. The

following sections describe each category in detail.

                                Table 4--2015 Ozone NAAQS Transition Obligations
----------------------------------------------------------------------------------------------------------------
                                      Designation for prior     Proposed NNSR/PSD     Other proposed transition
     Designation for 2015 NAAQS               NAAQS                obligations               obligations
----------------------------------------------------------------------------------------------------------------
1. Attainment......................  Attainment/Maintenance  PSD remains in effect.  --Area remains subject to
                                                                                existing CAA section 175A
                                                                                maintenance plan for the
                                                                                prior ozone NAAQS and
                                                                                requirements already in
                                                                                the SIP.
                                                                                --SIP subject to revision
                                                                                consistent with CAA
                                                                                sections 110(l) and 193.
                                                                                --Existing CAA section 175A
                                                                                maintenance plan, in
                                                                                combination with an
                                                                                approved PSD program,
                                                                                satisfies maintenance
                                                                                requirement under CAA
                                                                                section 110(a)(1).
2. Attainment......................  Nonattainment for 2008  Nonattainment NSR in    --Area remains subject to
                                      ozone NAAQS.            effect until            control measures that were
                                                              revocation of the       included in its adopted
                                                              2008 ozone NAAQS;       SIP to meet nonattainment
                                                              then PSD applies.       requirements.
                                                                                --Control measures can be
                                                                                modified in, or removed
                                                                                from, active SIP only with
                                                                                a CAA section 110(l)
                                                                                demonstration and a CAA
                                                                                section 193 demonstration
                                                                                if applicable.
                                                                                --Area's approved PSD
                                                                                program satisfies CAA
                                                                                section 110(a)(1)
                                                                                maintenance provision.
3. Nonattainment...................  Attainment/Maintenance  Nonattainment NSR       --Area remains subject to
                                                              applies based on 2015   existing CAA section 175A
                                                              ozone NAAQS             maintenance plan (if
                                                              classification.         applicable) for the prior
                                                                                NAAQS and requirements
                                                                                already in the SIP.
                                                                                --SIP subject to revision
                                                                                consistent with CAA
                                                                                sections 110(l) and 193.
4. Nonattainment...................  Nonattainment for 2008  Nonattainment NSR       --Area subject to all
                                      ozone NAAQS.            applies based on        applicable anti-
                                                              highest applicable      backsliding requirements
                                                              classification.         for 1-hr, 1997 and/or 2008
                                                                                NAAQS.
                                                                                --The area is no longer
                                                                                required to adopt any
                                                                                outstanding applicable
                                                                                requirements for 1997 and/
                                                                                or 2008 standards when the
                                                                                area is redesignated to
                                                                                attainment for the 2015
                                                                                ozone NAAQS, or for the
                                                                                revoked 1-hour, 1997 or
                                                                                2008 NAAQS when the EPA
                                                                                approves a redesignation
                                                                                substitute.
----------------------------------------------------------------------------------------------------------------

    i. Requirements for areas designated attainment for the 2015 ozone
NAAQS and maintenance for the 2008 ozone NAAQS. For this category, the
EPA is proposing that for areas designated attainment for the 2015
ozone NAAQS and maintenance for the 2008 ozone NAAQS, the area's
approved CAA section 175A maintenance plan for the revoked ozone NAAQS,
in combination with an approved PSD program, satisfies both its
obligations for maintenance under CAA section 110(a)(1) for the 2015
ozone NAAQS and its obligation to submit a second approvable
maintenance plan under CAA section 175A for the revoked ozone NAAQS.
This approach recognizes and reflects that such areas have in place an
ozone air quality management program that has successfully achieved
initial compliance with the 2015 ozone NAAQS and all previous ozone
NAAQS. Ongoing compliance with the 2015 ozone NAAQS in such areas will
be governed by the provisions of the area's approved SIP and the CAA's
general air quality management requirements in sections 107, 110 and
182. Any future revisions to the SIP would be subject to the general
``interference'' provisions of CAA section 110(l) and, if applicable,
the section 193 savings clause.\37\ Should the area subsequently
violate the 2015 ozone NAAQS, the contingency measures in the approved
maintenance plan would be triggered and the area may become subject to
a SIP call (under CAA section 110(k)(5)) or redesignation to
nonattainment (under CAA section 107(d)(3)).
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    \37\ Section 110(l) of the CAA indicates that EPA cannot approve
a SIP revision if the revision would interfere with any applicable
requirement concerning attainment and RFP, or any other applicable
requirement of the CAA. Section 193 of the CAA prohibits the
modification of any rule adopted before November 15, 1990 in areas
designated as nonattainment for an air pollutant unless the
modification insures equivalent or greater emission reductions of
the relevant pollutant.
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    ii. Areas designated attainment for the 2015 ozone NAAQS and
nonattainment for the 2008 ozone NAAQS. For this category, the EPA is
proposing that for areas designated attainment for the 2015 ozone NAAQS
and nonattainment for the 2008 ozone NAAQS, air agencies are relieved
of adopting any outstanding applicable requirements for the revoked
standards as of the effective date of the revocation; in other words,
these areas would not be subject to anti-backsliding requirements under
the principles of CAA section 172(e). We also propose that PSD SIPs for
these areas, once approved by the EPA, satisfy the obligation to submit
an approvable maintenance plan for the 2015 ozone NAAQS under CAA
section 110(a)(1).
    Areas designated attainment for the 2015 ozone NAAQS and
nonattainment for the 2008 ozone NAAQS have already attained the most
stringent existing standard, notwithstanding their existing designation
as nonattainment for the 2008 NAAQS. Because it is mathematically
impossible to attain the 2015 NAAQS without having first attained the
2008 NAAQS (i.e., 0.070 ppm is necessarily less than 0.075 ppm), EPA
considers these areas to have attained the 2008 NAAQS at the time of
revocation of that standard. These areas, thus, have implemented an air
quality management program that, in combination with federal measures
and emissions controls in upwind areas, has produced sufficient
emissions reductions to achieve air quality that has both attained the
prior ozone

NAAQS and resulted in an attainment designation for the more protective
2015 ozone NAAQS. In this case, EPA proposes that an air agency would
not be obligated to implement the applicable anti-backsliding
requirements set forth in 51.1300(p) and 93.109(c)(2) at the time the
2008 NAAQS is revoked in these areas. Because CAA section 172(e) only
speaks to creation of regulatory anti-backsliding requirements for
``areas which have not attained th[e] standard as of the date of
[revocation],'' the EPA believes it is appropriate to not require the
regulatory anti-backsliding requirements listed in 40 CFR 51.1300(p)
and 40 CFR 93.109(c)(2) in these areas which have attained the 2008
standard as of the date that standard is revoked (by virtue of an
attainment designation for a more stringent standard). These areas
would remain subject to the prior emissions control requirements
(including contingency measures) already approved into the SIP. The
prior nonattainment area control requirements already approved into the
SIP can be revised upon a showing that such revision complies with CAA
sections 110(l) and 193.
    Given the succession of NAAQS of increasing stringency that has
occurred, the EPA believes that the burden of developing a separate
approvable 110(a)(1) maintenance plan for the 2015 ozone NAAQS would
outweigh any compensating benefit for an area that is already attaining
that NAAQS and implementing, where applicable, any prior nonattainment
requirements that are already incorporated into the SIP and have been
sufficient to bring the area into attainment of both the prior and 2015
standards. Ongoing compliance with the 2015 ozone NAAQS in such areas
will be governed by the provisions of the area's approved SIP and the
CAA's general air quality management requirements in sections 107, 110
and 182. Should the area subsequently violate the 2015 ozone NAAQS, it
may become subject to a SIP call (under CAA section 110(k)(5)) or
redesignation to nonattainment (under CAA section 107(d)(3)).
    iii. Areas designated nonattainment for the 2015 ozone NAAQS and
maintenance for the 2008 ozone NAAQS. For this category, the EPA is
proposing that an area's approved CAA section 175A maintenance plan for
the 2008 ozone NAAQS in combination with nonattainment obligations
under the 2015 ozone NAAQS would satisfy the obligation to submit a
second approvable maintenance plan under CAA section 175A for the
revoked 2008 ozone NAAQS. Areas in this category would already be
subject to the provisions of an approved CAA section 175A maintenance
plan for the revoked 2008 ozone NAAQS and would have been redesignated
to attainment for the revoked 2008 ozone NAAQS. The EPA's approval of
the redesignation request and of the CAA section 175A maintenance plan
for the 2008 ozone NAAQS would require the EPA to determine not only
that all applicable requirements for the 2008 ozone NAAQS have been
met, but also that all applicable anti-backsliding measures for the
1997 and 1-hour standards have been adopted and approved into the SIP.
No revision to a CAA section 175A maintenance plan for these areas can
be approved unless it complies with the conditions of CAA sections
110(l) and 193, which would ensure the revision would not interfere
with attainment and RFP for the 2015 standards.
    Areas in this category would also be designated nonattainment for
the more stringent 2015 ozone NAAQS and, therefore, would be subject to
NNSR and other nonattainment requirements for their classification
under the more stringent 2015 ozone NAAQS. Thus, the EPA believes that
there is no useful purpose or justification for a second CAA section
175A maintenance plan that would apply only to the revoked 2008 ozone
NAAQS, in light of the nonattainment and eventual maintenance
requirements that apply for the more protective 2015 ozone NAAQS.
    iv. Areas designated nonattainment for the 2015 ozone NAAQS and
nonattainment for the 2008 ozone NAAQS. For this category, the EPA is
proposing that for an area designated nonattainment for the 2015 ozone
NAAQS and nonattainment for the 2008 NAAQS (as of revocation of the
standard), an air agency would be obligated to implement the applicable
anti-backsliding requirements set forth in 40 CFR 51.1300(p) and 40 CFR
93.109(c)(2) for the revoked 2008 ozone NAAQS. This could include, as
applicable, anti-backsliding requirements associated with the revoked
1-hour and 1997 ozone NAAQS if the area was also designated
nonattainment for one or more of these ozone NAAQS when that NAAQS was
revoked and the status of the area with respect to those revoked NAAQS
has not been changed through a redesignation substitute. Nonattainment
NSR would apply in these areas in accordance with their highest
nonattainment classification under any ozone standards for which they
are (or were as of the effective date of the revocation) designated
nonattainment.\38\ Also, if these areas are classified Severe or
Extreme as of the effective date of the revocation of a prior standard,
the fee program requirements of CAA section 185 in relation to that
prior standard would continue to apply.
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    \38\ In the case of an approved redesignation substitute, an air
agency seeking to remove NNSR provisions associated with a revoked
NAAQS from the active portion of the SIP must demonstrate
consistency with CAA sections 110(l) and 193.
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    v. Application of transition requirements to nonattainment and
attainment areas. For purposes of determining an area's transition
requirements, we would first look to the area's initial designation for
the 2015 ozone NAAQS. We would then determine the area's designation
and classification status for the 2008 ozone NAAQS as of the effective
date the 2008 ozone NAAQS is revoked. Finally, where appropriate, we
would determine whether anti-backsliding requirements for the 1997 and
1-hour ozone NAAQS apply in the area and, if so, we would determine the
area's designation and classification status for those standards as of
the dates they were revoked.\39\
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    \39\ If an area was initially designated attainment for the 2008
ozone NAAQS or was redesignated to attainment (``Maintenance'') for
the 2008 ozone NAAQS prior to the date of revocation of the 2008
NAAQS, then consistent with the position we took in the 2008 rule,
the area is no longer required to adopt any outstanding applicable
requirements for the revoked 1997 standard.
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5. Satisfaction of Anti-Backsliding Requirements for an Area
    The EPA is proposing to retain its current approach through which
an air agency may demonstrate that it is no longer required to adopt
any additional applicable requirements for an area that have not
already been approved into the SIP for a revoked ozone NAAQS. The final
2008 Ozone NAAQS SIP Requirements Rule adopted two acceptable
procedures that, if followed and approved by the EPA, address anti-
backsliding requirements associated with one or more revoked standards.
These two procedures--formal redesignation to attainment and
redesignation substitute--are described later. We are proposing to
retain these two procedures for purposes of revocation of the 2008
ozone NAAQS. After one of these procedures has resulted in an approval
by the EPA, an air agency seeking to revise its SIP to remove anti-
backsliding measures, such as NNSR provisions, from the active portion
of the SIP must demonstrate consistency with CAA sections 110(l) and
193 (if applicable). Requirements could then be shifted from the active
portion of the SIP to the contingency

measures portion of the SIP (80 FR 12304; March 6, 2015).
    The first of the proposed procedures is formal redesignation of the
area to attainment for the 2015 ozone NAAQS. For areas subject to anti-
backsliding requirements for the revoked 1997 or 2008 standards,
approval of a request for redesignation to attainment for the 2015
ozone NAAQS would signify that the air agency has satisfied its
obligations to adopt anti-backsliding requirements for the revoked 1997
or 2008 standards. Once the area is redesignated, the requirement(s)
for NNSR for the 2015 ozone NAAQS and for any prior ozone NAAQS cease
to apply, and the air agency may begin implementing the PSD program
requirements. Nonattainment NSR requirements may be removed from the
SIP, or may be retained as a maintenance plan contingency measure.\40\
This procedure is consistent with the EPA's longstanding interpretation
of NNSR requirements for areas that are redesignated to attainment.\41\
It is important to note that lifting the applicability of NNSR SIP
provisions in an area does not relieve sources in the area of their
obligations under previously established permit conditions.
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    \40\ States in the OTR may not use this flexibility because the
CAA requires all areas of the OTR including attainment areas to
implement, at a minimum, the NNSR requirements prescribed for
Moderate areas.
    \41\ See Greenbaum v. EPA, 370 F.3d 527, 534 (6th Cir. 2004)
(``The EPA argues that the Part D NSR program is inapplicable to
attainment areas, so that the requirement disappears upon
redesignation. After redesignation, Part D NSR is replaced by a PSD,
another permitting program designed to ensure maintenance of the
NAAQS in attainment areas. . . . The NSR program would not be
implemented as approved, as NSR programs are only required in
nonattainment areas.'')
---------------------------------------------------------------------------

    Redesignation to attainment would also terminate any obligations to
implement CAA section 185 fee programs in a Severe or Extreme area for
the 2015 or revoked 1997 or 2008 ozone NAAQS pursuant to the express
terms of CAA section 185. All of the remaining anti-backsliding
measures that have been approved into the SIP must continue to be
implemented unless or until the air agency can show that such
implementation is not necessary for maintenance, consistent with CAA
sections 110(l) and 193 if applicable.\42\
---------------------------------------------------------------------------

    \42\ This showing may be submitted to the EPA at the same time
as the maintenance plan, and may be approved by the EPA in a single
action. Subject to this process, anti-backsliding requirements
contained in the SIP could be shifted to the contingency measures
portion of a CAA section 175A maintenance plan or, in limited
circumstances (such as nonattainment NSR), removed from the SIP.
---------------------------------------------------------------------------

    The second of the proposed procedures for satisfying the anti-
backsliding requirements associated with a specific revoked standard is
referred to as a ``redesignation substitute.'' This redesignation
substitute showing would serve as a successor to redesignation to
attainment, for which the area would have been eligible were it not for
revocation. The showing is based on the CAA's criteria for
redesignation to attainment (CAA section 107(d)(3)(E)), but differs in
some important respects. This procedure does not require air agencies
to go through formal SIP submission procedures to submit a request for
approval of a redesignation substitute because the action is not a
redesignation under CAA section 107(d)(3)(E). States would have to
demonstrate that the area has attained the relevant revoked standard
and met all of the requirements for redesignation for that standard. An
area would then no longer be subject to any remaining applicable anti-
backsliding requirements associated with the specific revoked NAAQS,
including the major source thresholds and offset ratios associated with
the area's classification under those standards.\43\ The remaining NSR
requirements would be determined by the highest remaining
classification to which the area is subject, whether for the 2015 ozone
NAAQS or another revoked NAAQS for which the EPA had not approved a
redesignation substitute showing.
---------------------------------------------------------------------------

    \43\ An air agency seeking to remove NNSR provisions associated
with a revoked NAAQS from the active portion of the SIP must
demonstrate consistency with CAA sections 110(l) and 193.
---------------------------------------------------------------------------

6. Application of the EPA's Determination of Attainment Regulation
(``Clean Data Policy'') for Purposes of the Anti-Backsliding
Requirements
    The EPA is proposing to retain its current approach to implementing
the Clean Data Policy, under which a determination of attainment
suspends the obligation to submit certain attainment-related planning
requirements for the associated NAAQS for an area as long as the area
continues to attain those standards.\44\ This approach is codified at
40 CFR 51.1118 for the 2008 ozone NAAQS, and we are proposing to retain
the same approach for the 2015 ozone NAAQS at 40 CFR 51.1318, without
revision.
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    \44\ The EPA initially issued the Clean Data Policy in 1995,
``Reasonable Further Progress, Attainment Demonstration, and Related
Requirements for Ozone Nonattainment Areas Meeting the Ozone
National Ambient Air Quality Standard.'' Memorandum from John S.
Seitz, Director, Office of Air Quality Planning and Standards, May
10, 1995. For purposes of the 1997 ozone NAAQS, we codified that
policy at 40 CFR 51.918. This codified policy was upheld by the D.C.
Circuit in NRDC v. EPA, 571 F.3d 1245 (D.C. 2009).
---------------------------------------------------------------------------

    The planning elements that would be suspended under 40 CFR 51.1318
are the same as those suspended under existing 40 CFR 51.1118: RFP
requirements, attainment demonstrations, RACM, contingency measures and
other state planning requirements related to attainment of the relevant
standards. For a Severe or Extreme area, a CAA section 185 fee program
is expressly linked by the statute itself to an attainment plan.
Therefore, suspension of the obligation to submit the attainment plan
also necessarily suspends the obligation to submit the fee program
which is part of the attainment plan (provided that the EPA has not
already determined that the area failed to attain by its attainment
deadline and, thus, triggered the obligation to implement a fee
program). The EPA notes that a determination of attainment would not,
however, suspend obligations to submit non-planning requirements such
as NNSR, subpart 2 RACT or emission inventories under CAA section
182(a)(1).
    Under this proposed approach, the EPA's long-standing Clean Data
Policy, which has been upheld by the D.C. Circuit and all other courts
that have considered it, would remain embodied in a regulation
applicable for the purpose of all existing and prior ozone NAAQS. We