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Rule2026-11169

Revisions of the Nonattainment Designation for the 2008 and 2015 Ozone Standards and Clean Data Determinations for the 2008 and 2015 Ozone Standards: Cecil County, MD and New Castle County, DE

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Published

June 4, 2026

Effective

July 6, 2026

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is approving two separate requests from Maryland and Delaware to revise the designation for the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area for the 2008 primary and secondary ozone national ambient air quality standards (NAAQS) and the 2015 primary and secondary ozone NAAQS. Due to the concurrent requests from Maryland and Delaware, the EPA is revising the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area boundary into three distinct nonattainment areas that together cover the identical geographic area of the existing area. The EPA is also issuing clean data determinations (CDDs) for the revised Maryland and Delaware nonattainment areas for both the 2008 and 2015 ozone NAAQS. The EPA is taking this action pursuant to Clean Air Act (CAA) sections 107, 110, 172, and 182.

Full Text

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<title>Federal Register, Volume 91 Issue 107 (Thursday, June 4, 2026)</title>
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[Federal Register Volume 91, Number 107 (Thursday, June 4, 2026)]
[Rules and Regulations]
[Pages 33610-33617]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-11169]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R03-OAR-2025-1872; FRL-12994-02-R3]

Revisions of the Nonattainment Designation for the 2008 and 2015
Ozone Standards and Clean Data Determinations for the 2008 and 2015
Ozone Standards: Cecil County, MD and New Castle County, DE

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is approving two
separate requests from Maryland and Delaware to revise the designation
for the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE
nonattainment area for the 2008 primary and secondary ozone national
ambient air quality standards (NAAQS) and the 2015 primary and
secondary ozone NAAQS. Due to the concurrent requests from Maryland and
Delaware, the EPA is revising the Philadelphia-Wilmington-Atlantic
City, PA-NJ-MD-DE nonattainment area boundary into three distinct
nonattainment areas that together cover the identical geographic area
of the existing area. The EPA is also issuing clean data determinations
(CDDs) for the revised Maryland and Delaware nonattainment areas for
both the 2008 and 2015 ozone NAAQS. The EPA is taking this action
pursuant to Clean Air Act (CAA) sections 107, 110, 172, and 182.

DATES: This final rule is effective on July 6, 2026.

ADDRESSES: The EPA has established a docket for this action under
Docket ID Number EPA-R03-OAR-2025-1872. All documents in the docket are
listed on the <a href="http://www.regulations.gov">www.regulations.gov</a> website. Although listed in the
index, some information is not publicly available, e.g., confidential
business information (CBI) or other information whose disclosure is
restricted by statute. Certain other material, such as copyrighted
material, is not placed on the internet and will be publicly available
only in hard copy form. Publicly available docket materials are
available through <a href="http://www.regulations.gov">www.regulations.gov</a>, or please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section for
additional availability information.

FOR FURTHER INFORMATION CONTACT: Sarah McCabe, Planning &
Implementation Branch (3AD30), Air & Radiation Division, U.S.
Environmental Protection Agency, Region III, 1600 John F. Kennedy
Boulevard, Philadelphia, Pennsylvania 19103. The telephone number is
(215) 814-5786. Ms. McCabe can also be reached via electronic mail at
<a href="/cdn-cgi/l/email-protection#5b3638383a393e75283a293a331b3e2b3a753c342d"><span class="__cf_email__" data-cfemail="4d202e2e2c2f28633e2c3f2c250d283d2c632a223b">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

I. Background

On January 2, 2026, the EPA published a notice of proposed
rulemaking (NPRM) proposing to take several actions regarding the
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area
for the 2008 ozone NAAQS and 2015 ozone NAAQS.\1\
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\1\ 91 FR 98 (January 2, 2026).
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First, under the authority of CAA section 107(d)(3)(D), the EPA
proposed to split the identical geographic area of the Philadelphia-
Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area for both the
2008 and 2015 ozone NAAQS into three separate nonattainment areas: the
Cecil County, MD nonattainment area, the New Castle County, DE
nonattainment area, and the revised Philadelphia-Atlantic City, PA-NJ
nonattainment area. The EPA proposed that the air quality data,
emissions and emissions-related data, meteorology, geography/
topography, jurisdictional boundaries, and other air quality related
considerations, as well as planning and control considerations, support
both of the States' requests to reconsider the Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE nonattainment area boundary.
Second, pursuant to regulations at 40 Code of Federal Regulations
(CFR) 51.1118 and 51.1318, the EPA proposed to issue four CDDs for the
proposed Cecil County, MD nonattainment area and proposed New Castle
County, DE nonattainment area for the 2008 and 2015 ozone NAAQS.
For additional background information on this action, please refer
to the NPRM.

II. Summary of Maryland's Redesignation Request and EPA Analysis

On February 13, 2025, Governor Wes Moore and the Maryland
Department of the Environment (MDE) submitted a request and
accompanying five-factor analysis for the EPA to revise the boundary of
the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment
area for the 2008 and 2015 ozone NAAQS.\2\ Maryland

[[Page 33611]]

requested, under CAA section 107(d)(3)(D), to revise the boundary for
the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment
area by splitting it into two distinct nonattainment areas for the 2008
ozone NAAQS and 2015 ozone NAAQS: a Southern Philadelphia nonattainment
area encompassing all of Cecil County, MD, and a Central Philadelphia
nonattainment area encompassing the existing nonattainment area
counties in Delaware, New Jersey, and Pennsylvania. As discussed in
section V of this preamble, due to Delaware's similar concurrent
request, the EPA is revising the Philadelphia-Wilmington-Atlantic City,
PA-NJ-MD-DE nonattainment area into three distinct nonattainment areas.
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\2\ Maryland's submittal can be found in the docket of this rule
using Docket ID No. EPA-R03-OAR-2025-1872.
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The rationale for the EPA's actions is explained in the NPRM and
its associated technical support document (TSD) and will not be
restated here.

III. Summary of Delaware's Redesignation Request and EPA Analysis

On August 15, 2025, Governor Matt Meyer and the Delaware Department
of Natural Resources and Environmental Control (DNREC) submitted a
request and accompanying five-factor analysis for the EPA to revise the
boundary of the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE
nonattainment area for the 2008 and 2015 ozone NAAQS.\3\
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\3\ Delaware's submittal can be found in the docket of this
rulemaking using Docket ID No. EPA-R03-OAR-2025-1872.
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Delaware requested, under CAA section 107(d)(3)(D), to revise the
boundary for the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE
nonattainment area for the 2008 and 2015 ozone NAAQS to create a stand-
alone nonattainment area for New Castle County, Delaware. As discussed
in section V of this preamble, due to Maryland's similar concurrent
request, the EPA is revising the Philadelphia-Wilmington-Atlantic City,
PA-NJ-MD-DE nonattainment area into three distinct nonattainment areas.
The rationale for the EPA's actions is explained in the NPRM and
its associated technical support document (TSD) and will not be
restated here.

IV. EPA's Response to Comments Received

The EPA's January 2, 2026 NPRM (91 FR 98) opened a public comment
period, originally scheduled to close February 2, 2026 and extended by
one week (91 FR 2894, January 23, 2026), which closed on February 9,
2026. The EPA received two identical sets of comments from one
commenter. All comments received have been placed in the docket for
this action.
A summary of the relevant comments and the EPA's response thereto
are provided below.
Comment 1: The commenter requests that the EPA clearly articulate
the process and legal standards by which historic nonattainment areas
are proposed to be divided into smaller areas, given the regional
nature of the ozone problem.
Response 1: In the NPRM and the accompanying TSD, the EPA clearly
articulated the process and legal standards by which it proposed to
divide the former Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE
nonattainment area into three distinct smaller areas. The EPA is taking
this action under Clean Air Act section 107(d)(3)(D), which states,
``The Governor of any State may, on the Governor's own motion, submit
to the Administrator a revised designation of any area or portion
thereof within the State.'' In this case, Maryland Governor Wes Moore
and Delaware Governor Matt Meyer submitted requests under CAA section
107(d)(3)(D) on February 13, 2025 and August 15, 2025, respectively.
As stated in the NPRM in section IV,\4\ restated in section V.A in
this preamble, and explained in section II in the TSD,\5\ in
determining whether to approve or deny a state's request for a revision
to the designation of an area under CAA section 107(d)(3)(D), the EPA
considers the same factors as when the EPA initiates a revision to a
designation of an area on its own motion under CAA section
107(d)(3)(A). These CAA section 107(d)(3)(A) factors include ``air
quality data, planning and control considerations, or any other air
quality-related considerations the Administrator deems appropriate.''
Using CAA section 107(d)(3)(A) as a framework and referencing relevant
ozone designations guidance, the EPA considers five factors when
issuing initial area designations and when evaluating requests under
CAA section 107(d)(3)(D): air quality data, emissions and emissions-
related data, meteorology, geography/topography, and jurisdictional
boundaries.\6\ The EPA considered these same factors in its July 15,
2019 approval of Wisconsin's 107(d)(3)(D) request to revise the
boundary of an ozone nonattainment area into two distinct nonattainment
areas that together covered the identical geographic area of the
existing nonattainment area.\7\
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\4\ 91 FR 98, 100 (January 2, 2026).
\5\ Docket No. EPA-R03-OAR-2025-1872-0022, p. 5.
\6\ EPA memorandum titled ``Area Designations for the 2015 Ozone
National Ambient Air Quality Standards,'' February 25, 2016, Docket
No. EPA-R03-OAR-2025-1872-0020.
\7\ See 84 FR 4422, 4423-24 (February 15, 2019) (proposed) and
84 FR 33699 (July 15, 2019) (final).
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CAA section 107(d)(1)(A)(i) defines ``nonattainment'' as ``any area
that does not meet (or that contributes to ambient air quality in a
nearby area that does not meet)'' the NAAQS. The EPA is concluding in
this action that the available information, applying the aforementioned
factors as discussed in the NPRM and TSD, demonstrates that the Cecil
County, MD nonattainment area does not contribute to a violation of the
2008 or 2015 ozone NAAQS in the Philadelphia-Atlantic City, PA-NJ
nonattainment area or the New Castle County, DE nonattainment area
(there is no violation in this area). Likewise, the EPA finds that the
available information, applying the aforementioned factors as discussed
in the NPRM and TSD, demonstrates that the New Castle County, DE
nonattainment area does not contribute to a violation of the 2008 or
2015 ozone NAAQS in the Philadelphia-Atlantic City, PA-NJ nonattainment
area or the Cecil County, MD nonattainment area (there is no violation
in this area). For both Cecil County, MD and New Castle County, DE, an
analysis of the five recommended factors and a weight-of-evidence
approach described in detail in the TSD supports this conclusion. Thus,
for reasons outlined in the proposed rule and associated TSD, the EPA
has determined that it is appropriate that the three areas be
considered separate for implementation and planning purposes.
With respect to the comment's statement that ozone problems are of
a regional nature, the EPA notes, in the context of the agency deciding
on a CAA section 107(d)(3)(D) request to revise the boundaries of a
nonattainment area, that the aforementioned factors are meant to assist
the EPA in analyzing whether the portion of the nonattainment area in
the requesting state contributes to a violation of the ozone NAAQS
elsewhere in the larger nonattainment area. Thus, the five-factor
analysis accounts for the regional nature of ozone issues at a local
level. More broadly speaking, separate from this action, the New Castle
County, DE and Cecil County, MD nonattainment areas will continue to be
part of the ozone transport region (OTR) and this final action does not
alleviate these areas from OTR requirements outlined in 40

[[Page 33612]]

CFR 51.1116 and 40 CFR 51.1316 in accordance with CAA sections 176A and
184.
Comment 2: The commenter states that the proposal makes no mention
of CAA section 107(e) or how the EPA may have determined what states
are, or are not, significantly affected. The commenter asks the EPA to
explicitly state how the proposal satisfies CAA section 107(e). The
commenter further requests that interested stakeholders have adequate
time to review this process to ensure the proposed redesignations
adhere to CAA requirements, specifically those established in CAA
section 107(e)(2).
Response 2: The EPA disagrees. The EPA is not taking this action
under CAA section 107(e), which relates to Redesignation of air quality
control regions (AQCRs). AQCRs are codified in 40 CFR part 81 subpart
B, Designation of Air Quality Control Regions.
The EPA is taking this action under CAA section 107(d),
Designations, and more specifically 107(d)(3)(D), Redesignation, which
is codified in 40 CFR part 81 subpart C, Section 107 Attainment Status
Designations. In 40 CFR part 81 subpart C, the EPA is amending 40 CFR
81.308 (Delaware), 81.321 (Maryland), 81.331 (New Jersey), and 81.339
(Pennsylvania). In this final action, the EPA is not proposing to
redesignate an AQCR or amend any provision in 40 CFR part 81, subpart B
\8\ where AQCRs are codified. As such, CAA section 107(e) is not
applicable to this rule.
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\8\ See 40 CFR 81.15 for the counties in the Metropolitan
Philadelphia Interstate AQCR (PA-NJ-DE). This AQCR does not
encompass the same area nor is it equivalent to the former
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment
area for the 2008 and 2015 ozone NAAQS.
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The comment period for the proposal ran from January 2, 2026 to
February 9, 2026, which included a 7-day comment period extension. The
duration of the comment period provided stakeholders with adequate time
to review the proposal and supporting documentation. Furthermore, as
the request in the comment for adequate time to review is based on CAA
section 107(e)(2) which is inapplicable to this action, the basis for
the request is inapplicable.

V. Final Action

In this rule, the EPA is finalizing six actions. In two separate
actions, under the authority of CAA section 107(d)(3)(D), the EPA is
approving Maryland's and Delaware's separate requested revisions to the
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area.
To account for both requests, the EPA is revising the Philadelphia-
Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area for the 2008
ozone NAAQS and 2015 ozone NAAQS into three separate nonattainment
areas that together cover the identical geographic area of the original
nonattainment area. Second, pursuant to regulations at 40 CFR 51.1118
and 51.1318, the EPA is issuing two CDDs for the Cecil County, MD
nonattainment area for the 2008 and 2015 ozone NAAQS and two CDDs for
the New Castle County, DE nonattainment area for the 2008 and 2015
ozone NAAQS.

A. Revisions to the Philadelphia Nonattainment Area Boundary

In determining whether to approve or deny a state's request for a
revision to the designation of an area under CAA section 107(d)(3)(D),
the EPA considers the same factors when the EPA initiates a revision to
a designation of an area on its own motion under CAA section
107(d)(3)(A). These CAA section 107(d)(3)(A) factors include ``air
quality data, planning and control considerations, or any other air
quality-related considerations the Administrator deems appropriate.''
Using CAA section 107(d)(3)(A) as a framework, the EPA considers five
factors when issuing initial area designations and when evaluating
requests under CAA section 107(d)(3)(D): air quality data, emissions
and emissions-related data, meteorology, geography/topography, and
jurisdictional boundaries.\9\ Section 107(d)(1)(A)(i) of the CAA
defines ``nonattainment'' as ``any area that does not meet (or that
contributes to ambient air quality in a nearby area that does not
meet)'' the NAAQS. Therefore, consistent with the statute the EPA will
not redraw the boundaries of nonattainment areas where one portion of
the area contributes to the nonattainment of another portion of the
area.
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\9\ The March 28, 2000, memorandum entitled ``Boundary Guidance
on Air Quality Designations for the 8-Hour Ozone National Ambient
Air Quality Standards,'' the December 4, 2008, memorandum entitled
``Area Designations for the 2008 Revised Ozone National Ambient Air
Quality Standards,'' and the February 25, 2016, memorandum entitled
``Area Designations for the 2015 Ozone National Ambient Air Quality
Standards'' can be found in the docket of this rule using Docket ID
No. EPA-R03-OAR-2025-1872.
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The EPA is finalizing this rule as proposed. The EPA concludes that
the available information demonstrates that the requested Cecil County,
MD nonattainment area does not contribute to a violation of the 2015
ozone NAAQS in the remaining Philadelphia-Atlantic City, PA-NJ
nonattainment area or the requested New Castle County, DE nonattainment
area. The EPA also concludes that the available information
demonstrates that the requested New Castle County, DE nonattainment
area does not contribute to a violation of the 2015 ozone NAAQS in the
remaining Philadelphia-Atlantic City, PA-NJ nonattainment area or the
requested Cecil County, MD nonattainment area.
Thus, the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE
nonattainment area for the 2008 and 2015 ozone NAAQS, is now split into
three distinct nonattainment areas that together cover the identical
geographic area of the original area. One of the separate areas, called
the ``Cecil County, MD Nonattainment Area,'' consists of Cecil County,
MD. The other separate area, called the ``New Castle County, DE
Nonattainment Area,'' consists of New Castle County, DE. The revised
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area
consists of the remaining existing nonattainment area counties in New
Jersey and Pennsylvania, and is called the ``Philadelphia-Atlantic
City, PA-NJ'' nonattainment area.\10\
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\10\ The remaining counties making up the Philadelphia-Atlantic
City, PA-NJ nonattainment area are: Atlantic County, Burlington
County, Camden County, Cape May County, Cumberland County,
Gloucester County, Mercer County, Ocean County, and Salem County in
New Jersey; and Bucks County, Chester County, Delaware County,
Montgomery County, and Philadelphia County in Pennsylvania.
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All areas continue to be designated nonattainment and classified as
Marginal for the 2008 ozone NAAQS and classified as Serious for the
2015 ozone NAAQS.
The rationale for the EPA's revisions to the boundary of the
Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE nonattainment area
is further explained in the NPRM and its associated TSD.\11\
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\11\ Docket No. EPA-R03-OAR-2025-1872-0022.
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B. Clean Data Determinations

In accordance with 40 CFR 51.1118 and 51.1318, the EPA is
determining that the Cecil County, MD nonattainment area and New Castle
County, DE nonattainment area are attaining the 2008 and 2015 ozone
NAAQS. Because the 2015 ozone NAAQS retains the same general form and
averaging time as the 2008 ozone NAAQS, but is set at a more protective
level, the EPA's analysis for the 2015 ozone NAAQS CDD suffices as a
CDD analysis for the less stringent 2008 ozone NAAQS.
The Cecil County, MD nonattainment area CDD is based upon two
three-year

[[Page 33613]]

periods of complete, quality-assured and certified data for the 2021-
2023 and 2022-2024 monitoring periods from the Fair Hill monitor with
site ID 24-015-0003. The most recent three-year ozone design value for
the Cecil County, MD nonattainment area is 67 parts per billion (ppb),
which meets the 2015 ozone NAAQS. Therefore, in this final rule, the
EPA is determining that the Cecil County, MD nonattainment area is
attaining the 2008 and 2015 ozone NAAQS.
The New Castle County, DE nonattainment area CDD is based upon two
three-year periods of complete, quality-assured and certified data for
the 2021-2023 and 2022-2024 monitoring periods. There are four Federal
Reference Method/Federal Equivalent Method monitors within the New
Castle County, DE nonattainment area. Where several monitors are
located in a county (or a designated nonattainment area or maintenance
area), the design value for the county or area is determined by the
monitor with the highest level. The highest most recent three-year
ozone design value for the New Castle County, DE nonattainment area is
68 ppb, which meets the 2015 ozone NAAQS. Therefore, in this rule, the
EPA is determining that the New Castle County, DE nonattainment area is
attaining the 2008 and 2015 ozone NAAQS.
The requirements for MDE and DNREC to submit attainment
demonstrations, and associated reasonably available control measures
(RACM), reasonable further progress (RFP) plans, contingency measures,
and any other planning requirements related to attainment of the 2015
ozone NAAQS for the Cecil County, MD nonattainment area and New Castle
County, DE nonattainment area, are suspended unless the EPA rescinds
the CDDs due to an area no longer attaining the 2015 ozone NAAQS.
Similarly, these same requirements related to attainment of the 2008
ozone NAAQS for the Cecil County, MD nonattainment area and New Castle
County, DE nonattainment area, are suspended unless the EPA rescinds
the CDDs due to an area no longer attaining the 2008 ozone NAAQS. This
rule does not constitute redesignation of the areas to attainment of
the 2008 or 2015 ozone NAAQS under section 107(d)(3)(E) of the CAA, nor
does it constitute approval of maintenance plans for the areas as
required under section 175A of the CAA, nor does it find that the areas
have met all other requirements for redesignation. The Cecil County, MD
nonattainment area and New Castle County, DE nonattainment area will
remain designated nonattainment for the 2008 and 2015 ozone NAAQS until
such time as the States request and the EPA determines that an area
meets CAA requirements for redesignation to attainment and takes
separate action to redesignate an area.
The rationale for the EPA's clean data determinations is further
explained in the NPRM and its associated TSD.

VI. Statutory and Executive Order Reviews

This final rule finalizes revisions to the boundary of an existing
ozone nonattainment area by splitting it into three separate
nonattainment areas that together cover the identical geographic area
of the original nonattainment area. It also finalizes CDDs for the two
new areas in Cecil County, MD and New Castle County, DE resulting from
the revisions, which suspend the requirement to submit certain
attainment plan requirements for the 2008 and 2015 ozone NAAQS. This
rule action does not impose additional requirements. For that reason,
this action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<bullet> Is not an Executive Order 14192 (90 FR 9065, February 6,
2025) regulatory action because this action is not significant under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it is not a significant regulatory action under
Executive Order 12866;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act.
In addition, this rule is not approved to apply on any Indian
reservation land or in any other area where the EPA or an Indian tribe
has demonstrated that a tribe has jurisdiction. In those areas of
Indian country, the rule does not have tribal implications and will not
impose substantial direct costs on tribal governments or preempt tribal
law as specified by Executive Order 13175 (65 FR 67249, November 9,
2000).
This action is subject to the Congressional Review Act, and the EPA
will submit a rule report to each House of the Congress and to the
Comptroller General of the United States. This action is not a ``major
rule'' as defined by 5 U.S.C. 804(2).
Under section 307(b)(1) of the Clean Air Act, petitions for
judicial review of this action must be filed in the United States Court
of Appeals for the appropriate circuit by August 3, 2026. Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this action for the purposes of
judicial review nor does it extend the time within which a petition for
judicial review may be filed, and shall not postpone the effectiveness
of such rule or action. This action may not be challenged later in
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects

40 CFR Part 52

Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Ozone,
Volatile organic compounds.

40 CFR Part 81

Environmental protection, Air pollution control, Designations,
Intergovernmental relations, Redesignation, Reporting and recordkeeping
requirements, Nitrogen dioxide, Ozone, Volatile organic compounds.

Amy Van Blarcom-Lackey,
Regional Administrator, Region III.
Michael Martucci,
Regional Administrator, Region II.
For the reasons stated in the preamble, the EPA amends 40 CFR parts
52 and 81 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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

[[Page 33614]]

Subpart I--Delaware

0
2. Section 52.426 is amended by adding paragraphs (j) and (k) to read
as follows:

Sec. 52.426 Control strategy plans for attainment and rate-of-
progress: ozone.

* * * * *
(j) Determination of attainment. EPA has determined, as of June 4,
2026, that based on 2022 to 2024 ambient air quality data, the New
Castle County, DE 8-hour ozone marginal nonattainment area has attained
the 2008 8-hour ozone NAAQS. This determination, in accordance with 40
CFR 51.1118, suspends the requirements for this area to submit an
attainment demonstration, associated reasonably available control
measures, a reasonable further progress plan, contingency measures, and
other planning SIPs related to attainment of the standard for as long
as this area continues to meet the 2008 annual 8-hour ozone NAAQS.
(k) Determination of attainment. EPA has determined, as of June 4,
2026, that based on 2022 to 2024 ambient air quality data, the New
Castle County, DE 8-hour ozone serious nonattainment area has attained
the 2015 8-hour ozone NAAQS. This determination, in accordance with 40
CFR 51.1318, suspends the requirements for this area to submit an
attainment demonstration, associated reasonably available control
measures, a reasonable further progress plan, contingency measures, and
other planning SIPs related to attainment of the standard for as long
as this area continues to meet the 2015 annual 8-hour ozone NAAQS.

Subpart V--Maryland

0
3. Section 52.1076 is amended by adding paragraphs (kk) and (ll) to
read as follows:

Sec. 52.1076 Control strategy plans for attainment and rate-of-
progress: Ozone.

* * * * *
(kk) EPA has determined, as of June 4, 2026, that based on 2022 to
2024 ambient air quality data, the Cecil County, MD marginal
nonattainment area for the 2008 8-hour ozone national ambient air
quality standards (2008 ozone NAAQS) has attained the 2008 ozone NAAQS.
This determination, in accordance with 40 CFR 51.1118, suspends the
requirements for this area to submit an attainment demonstration,
associated reasonably available control measures, a reasonable further
progress plan, contingency measures, and other planning SIPs related to
attainment of the standard for as long as this area continues to meet
the 2008 ozone NAAQS.
(ll) EPA has determined, as of June 4, 2026, that based on 2022 to
2024 ambient air quality data, the Cecil County, MD serious
nonattainment area for the 2015 8-hour ozone national ambient air
quality standards (2015 ozone NAAQS) has attained the 2015 ozone NAAQS.
This determination, in accordance with 40 CFR 51.1318, suspends the
requirements for this area to submit an attainment demonstration,
associated reasonably available control measures, a reasonable further
progress plan, contingency measures, and other planning SIPs related to
attainment of the standard for as long as this area continues to meet
the 2015 ozone NAAQS.

PART 81--DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES

0
4. The authority citation for part 81 continues to read as follows:

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

Subpart C--Section 107 Attainment Status Designations

0
5. Section 81.308 is amended:
0
a. In the table entitled ``Delaware--2008 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry for ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE: New Castle County'' and adding the entry
``New Castle County'' in its place; and
0
b. In the table entitled ``Delaware--2015 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry for ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE New Castle County'' and adding the entry
``New Castle County'' in its place.
The revisions read as follows:

Sec. 81.308 Delaware.

* * * * *

Delaware--2008 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area ---------------------------------------------------------------------------
Date \1\ Type Date \1\ Type
----------------------------------------------------------------------------------------------------------------
New Castle County \2\............... 7/6/2026 Nonattainment.......... 6/3/2016 Marginal.\4\

* * * * * * *
----------------------------------------------------------------------------------------------------------------
\1\ This date is July 20, 2012, unless otherwise noted.
\2\ Excludes Indian country located in each area, unless otherwise noted.
* * * * * * *
\4\ Attainment date is extended to July 20, 2016.

Delaware--2015 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated Area \1\ ---------------------------------------------------------------------------
Date \2\ Type Date \2\ Type
----------------------------------------------------------------------------------------------------------------
New Castle County................... 7/6/2026 Nonattainment.......... 7/30/2024 Serious.

* * * * * * *
----------------------------------------------------------------------------------------------------------------
\1\ Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the
boundaries of any area of Indian country in this table, including any area of Indian country located in the
larger designation area. The inclusion of any Indian country in the designation area is not a determination
that the state has regulatory authority under the Clean Air Act for such Indian country.
\2\ This date is August 3, 2018, unless otherwise noted.

[[Page 33615]]

* * * * *

0
6. Section 81.321 is amended:
0
a. In the table entitled ``Maryland--2008 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry for ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE: Cecil County'' and adding the entry ``Cecil
County'' in its place; and
0
b. In the table entitled ``Maryland--2015 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry for ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE Cecil County'' and adding the entry ``Cecil
County'' in its place.
The revisions read as follows:

Sec. 81.321 Maryland.

* * * * *

Maryland--2008 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area ---------------------------------------------------------------------------
Date \1\ Type Date \1\ Type
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Cecil County \2\.................... 7/6/2026 Nonattainment.......... 6/3/2016 Marginal.\4\

Maryland--2015 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area \1\ ---------------------------------------------------------------------------
Date \2\ Type Date \2\ Type
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Cecil County........................ 7/6/2026 Nonattainment.......... 7/30/2024 Serious.

* * * * *

0
7. Section 81.331 is amended:
0
a. In the table entitled ``New Jersey--2008 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE'' and its accompanying subordinate entries
and adding the entry ``Philadelphia-Atlantic City, PA-NJ'' and
accompanying subordinate entries in its place; and
0
b. In the table entitled ``New Jersey--2015 8-Hour Ozone NAAQS [Primary
and secondary]'' by removing the entry for ``Philadelphia-Wilmington-
Atlantic City, PA-NJ-MD-DE'' and its accompanying subordinate entries
and adding the entry ``Philadelphia-Atlantic City, PA-NJ'' and its
accompanying subordinate entries in its place.
The additions read as follows:

Sec. 81.331 New Jersey.

* * * * *

New Jersey--2008 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area ---------------------------------------------------------------------------
Date \1\ Type Date \1\ Type
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Philadelphia-Atlantic City, PA-NJ ........... Nonattainment.......... 6/3/2016 Marginal.\3\
\2\
Atlantic County................. ........... ....................... ........... .......................
Burlington County............... ........... ....................... ........... .......................
Camden County................... ........... ....................... ........... .......................
Cape May County................. ........... ....................... ........... .......................
Cumberland County............... ........... ....................... ........... .......................
Gloucester County............... ........... ....................... ........... .......................
Mercer County................... ........... ....................... ........... .......................
Ocean County.................... ........... ....................... ........... .......................
Salem County.................... ........... ....................... ........... .......................
----------------------------------------------------------------------------------------------------------------
\1\ This date is July 20, 2012, unless otherwise noted.

[[Page 33616]]

\2\ Excludes Indian country located in each area, unless otherwise noted.
\3\ Attainment date is extended to July 20, 2016.

New Jersey--2015 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area \1\ ---------------------------------------------------------------------------
Date \2\ Type Date \2\ Type
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Philadelphia-Atlantic City, PA-NJ ........... Nonattainment.......... 7/30/2024 Serious.
Atlantic County................. ........... ....................... ........... .......................
Burlington County............... ........... ....................... ........... .......................
Camden County................... ........... ....................... ........... .......................
Cape May County................. ........... ....................... ........... .......................
Cumberland County............... ........... ....................... ........... .......................
Gloucester County............... ........... ....................... ........... .......................
Mercer County................... ........... ....................... ........... .......................
Ocean County.................... ........... ....................... ........... .......................
Salem County.................... ........... ....................... ........... .......................
----------------------------------------------------------------------------------------------------------------
\1\ Includes any Indian country in each county or area, unless otherwise specified. EPA is not determining the
boundaries of any area of Indian country in this table, including any area of Indian country located in the
larger designation area. The inclusion of any Indian country in the designation area is not a determination
that the state has regulatory authority under the Clean Air Act for such Indian country.
\2\ This date is August 3, 2018, unless otherwise noted.

* * * * *

0
8. Section 81.339 is amended:
0
a. In the table entitled ``Pennsylvania--2008 8-Hour Ozone NAAQS
[Primary and secondary]'' by removing the entry for ``Philadelphia-
Wilmington-Atlantic City, PA-NJ-MD-DE'' and its accompanying
subordinate entries and adding the entry ``Philadelphia-Atlantic City,
PA-NJ'' and its accompanying subordinate entries in its place; and
0
b. in the table entitled ``Pennsylvania--2015 8-Hour Ozone NAAQS
[Primary and secondary]'' by removing the entry for ``Philadelphia-
Wilmington-Atlantic City, PA-NJ-MD-DE'' and its accompanying
subordinate entries and adding the entry ``Philadelphia-Atlantic City,
PA-NJ'' and its accompanying subordinate entries in its place.
The additions read as follows:

Sec. 81.339 Pennsylvania.

* * * * *

Pennsylvania--2008 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area ---------------------------------------------------------------------------
Date \1\ Type Date \1\ Type
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Philadelphia-Atlantic City, PA-NJ ........... Nonattainment.......... 6/3/2016 Marginal.\4\
\2\
Bucks County.................... ........... ....................... ........... .......................
Chester County.................. ........... ....................... ........... .......................
Delaware County................. ........... ....................... ........... .......................
Montgomery County............... ........... ....................... ........... .......................
Philadelphia County............. ........... ....................... ........... .......................
----------------------------------------------------------------------------------------------------------------
\1\ This date is July 20, 2012, unless otherwise noted.
\2\ Excludes Indian country located in each area, unless otherwise noted.
* * * * * * *
\4\ Attainment date is extended to July 20, 2016.

Pennsylvania--2015 8-Hour Ozone NAAQS
[Primary and secondary]
----------------------------------------------------------------------------------------------------------------
Designation Classification
Designated area \1\ ---------------------------------------------------------------------------
Date \2\ Type Date \2\ Type
----------------------------------------------------------------------------------------------------------------
Philadelphia-Atlantic City, PA-NJ ........... Nonattainment.......... 7/30/2024 Serious.
Bucks County.................... ........... ....................... ........... .......................
Chester County.................. ........... ....................... ........... .......................
Delaware County................. ........... ....................... ........... .......................
Montgomery County............... ........... ....................... ........... .......................
Philadelphia County............. ........... ....................... ........... .......................

[[Page 33617]]

* * * * *

[FR Doc. 2026-11169 Filed 6-3-26; 8:45 am]
BILLING CODE 6560-50-P

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