SUPPLEMENTARY INFORMATION:

Throughout this document whenever “we,” “us,” or “our” is used, we mean the EPA. ( printed page 27208)

I. Background Information

The Illinois Environmental Protection Agency (Illinois EPA) submitted SIP revisions on December 18, 2024, to address Moderate area requirements for the Chicago and Metro East areas under the 2015 ozone NAAQS. These submittals contained several nonattainment plan elements, including an updated 2017 base year emissions inventory for volatile organic compounds (VOC) and oxides of nitrogen (NO_X), a 15% RFP plan with 2023 VOC and NO_X motor vehicle emissions budgets, an I/M program certification, and an NNSR certification. The submittals also included an attainment demonstration, a reasonably available control measures demonstration, and contingency measures, which are not being addressed in this action. Illinois' SIP submittals and associated supporting documents are available in the docket for this action. On February 12, 2026 (91 FR 6568), the EPA proposed to approve portions of Illinois' attainment plan SIP revision request, dated December 18, 2024, pursuant to section 110 and part D of CAA. 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 and will not be restated here. The public comment period for this proposed rule ended on March 16, 2026. The EPA received no comments on the proposal; therefore, we are finalizing our action as proposed.

II. Final Action

The EPA is approving portions of Illinois' attainment plan SIP revision request, dated December 18, 2024, pursuant to section 110 and part D of CAA. The EPA is approving Illinois' updated 2017 base year emissions inventory, RFP demonstration including 2023 budgets, I/M certification, and NNSR requirements of the CAA for the Chicago and Metro East nonattainment areas for the 2015 ozone NAAQS. The EPA is also finding adequate and approving the 2023 motor vehicle emissions budgets for the Chicago and Metro East St. Louis Moderate ozone nonattainment areas included in this SIP submittal.

III. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submittal 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 submittals, 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 anExecutive Order 14192 (90 FR 9065, February 6, 2025) regulatory action because this action is not significant under Executive Order 12866;
• 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 CAA.

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 July 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 27207