SUPPLEMENTARY INFORMATION:

Throughout this document whenever “we,” “us,” or “our” is used, we mean the EPA.

I. Background

On May 19, 2025 (90 FR 21254), the EPA proposed to approve Ohio's plans for maintaining the 2008 ozone NAAQS through 2036 in the Columbus area and through 2037 in the Cleveland-Akron-Lorain and Cincinnati areas as revisions to the Ohio SIP. The EPA also proposed to find adequate and approve the volatile organic compounds (VOC) and nitrogen oxides (NO_X) motor vehicle emission budgets (Budgets) for 2036 for the Columbus area and for 2037 for the Cleveland-Akron-Lorain and Cincinnati areas (90 FR 21254). An explanation of the CAA requirements, a detailed analysis of the revisions, and the EPA's reasons for proposing approval were provided in the notice of proposed rulemaking. The public comment period for this proposed rule ended on June 18, 2025. The EPA received two comments on the proposal.

II. Response to Comments

EPA received two anonymous comments during the comment period. Summaries of the comments and the EPA's response are provided below. The full comments are in the rulemaking docket; see Addresses for details on accessing the docket.

Comment 1: The commenter suggests that Ohio needs a plan to be carbon neutral by 2030 and recommends disapproving the 2008 ozone second maintenance plans for Ohio until the State “deconstructs, degrowth, retreats and rewilds 10% of the proposed areas.”

Comment 2: The commenter recommends disapproving the 2008 ozone second maintenance plans for Ohio until the State adopts California's strict air quality laws.

Response: The requirement for a State to submit a maintenance plan demonstrating attainment of the NAAQS in an area for an additional 10 years beyond the initial 10-year maintenance period is set forth in section 175A of the CAA. In a 1992 Memorandum entitled “Procedures for Processing Requests to Redesignate Areas to Attainment,” the EPA has long-standing guidance for States on developing maintenance plans.^[1] It explains that a maintenance plan should address five elements: (1) an attainment emission inventory; (2) a maintenance demonstration; (3) a commitment for continued air quality monitoring; (4) a process for verification of continued attainment; and (5) a contingency plan. Ohio's maintenance plans for the 2008 ozone NAAQS address each of these components of a maintenance plan and meet the requirements of section 175A of the CAA. The received comments regarding Ohio adopting a plan for carbon neutrality and equivalent air quality laws to California are beyond the scope of this action. These comments have no bearing on the EPA's proposed approval of Ohio's 2008 ozone second maintenance plans as the plans fulfill the requirements under section 175A of the CAA.

III. Emission Inventories

After the comment period for the notice of proposed rulemaking closed on June 18, 2025, Ohio EPA discovered errors in the emission inventories affecting area sources in the Columbus and Cleveland-Akron-Lorain areas and point, area, and nonroad sources in the Cincinnati area. On August 19, 2025, Ohio EPA submitted a supplement to the State's plans to correct the emission inventories for each area. The procedures used to develop the emission inventories were documented in the notice of proposed rulemaking (90 FR 21254).

The EPA evaluated Ohio's corrected attainment and maintenance year emission inventories. Just as with Ohio's original emission inventories, the corrected emission inventories continue to demonstrate maintenance of the 2008 ozone standard in the Columbus, Cleveland-Akron-Lorain, and Cincinnati areas by showing that future emissions of NO_X and VOC will remain at or below attainment year emission levels when considering both future source growth and implementation of future controls. ( printed page 6518)

Attainment inventories for the Columbus area are in Tables 1 and 2, attainment inventories for the Cleveland-Akron-Lorain area are in Tables 3 and 4, and attainment inventories for the Cincinnati area are in Tables 5 and 6.

Ohio EPA demonstrated maintenance through 2036 for the Columbus area and through 2037 for the Cleveland-Akron-Lorain and Cincinnati areas by showing that future VOC and NO_X emissions remain at or below attainment year emission levels. The 2036 summer day emission inventories for the Columbus area are in Tables 7 and 8, and changes in VOC and NO_X emissions in the Columbus area between 2016 and 2036 are summarized in Table 9. The 2037 summer day emission inventories for the Cleveland-Akron-Lorain area are in Tables 10 and 11, and changes in VOC and NO_X emissions in the Cleveland-Akron-Lorain area between 2016 and 2037 are summarized in Table 12. The 2037 summer day emission inventories for the Cincinnati area are in Tables 13 and 14, and changes in VOC and NO_X emissions in the Cincinnati area between 2016 and 2037 are summarized in Table 15.

IV. Motor Vehicle Emission Budgets

EPA is finding adequate and approving motor vehicle emission budgets for use to determine transportation conformity in the Columbus, Cleveland-Akron-Lorain, and Cincinnati areas. Detailed information on the transportation conformity program and the EPA's reasons for proposing approval can be found in our May 19, 2025 (90 FR 21254), proposed approval of Ohio's second maintenance plans for the 2008 ozone NAAQS. NO_X and VOC Budgets for the last year of the maintenance periods for the Columbus area (2036), the Cleveland-Akron-Lorain area (2037), and the Cincinnati area (2037) are included in Table 16.

Updates to emission inventories in the point, area, and nonroad sectors result in updates to each area's safety margins. The Columbus area is projected to have a safety margin of 40.96 tpd for NO_X and 14.51 tpd for VOC in 2036 (Table 9). The Cleveland-Akron-Lorain area is projected to have a safety margin of 82.05 tpd for NO_X and 35.07 tpd for VOC in 2037 (Table 12). The Cincinnati area is projected to have a safety margin of 102.23 tpd for NO_X and 18.16 tpd for VOC in 2037 (Table 15). As shown in Table 16, the portions of each area's safety margins allocated to the mobile source sector are still less than each area's entire available safety margins.

V. What action is the EPA taking?

The EPA is approving the second maintenance plans for the 2008 ozone NAAQS submitted by Ohio EPA on November 6, 2024, as revisions to the Ohio SIP. These second maintenance plans are designed to keep the Columbus area in attainment of the 2008 ozone NAAQS through 2036, the Cleveland-Akron-Lorain area in attainment of the 2008 ozone NAAQS through 2037, and the Cincinnati area in attainment of the 2008 ozone NAAQS through 2037. The EPA is finding adequate and approving the newly established Budgets for the Columbus, Cleveland-Akron-Lorain, and Ohio portion of the Cincinnati maintenance areas.

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget underExecutive Order 12866 (58 FR 51735, October 4, 1993);
• Is not subject toExecutive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866; ( printed page 6523)
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• 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.);
• 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);
• Does not have federalism implications as specified inExecutive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject toExecutive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;
• Is not a significant regulatory action subject toExecutive Order 13211 (66 FR 28355, May 22, 2001); and
• 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, the SIP 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 CAA, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by April 13, 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).)

For the reasons stated in the preamble, title 40 CFR part 52 is amended as follows:

91 FR 6517