Summary:
In the Proposed Rules section of this Federal Register, EPA is proposing approval of portions of State Implementation Plan (SIP) submissions from the State of Colorado dated June 26, 2023, May 23, 2024, May 30, 2024, and April 2, 2025. The submissions relate to Colorado Air Quality Control Commission Regulation Number 7 (Reg. 7) and Regulation Number 26 (Reg. 26), and address Colorado's SIP obligations for the Reasonably Available Control Technology (RACT) Serious ozone nonattainment area requirement for the 2008 ozone National Ambient Air Quality Standard (NAAQS). In this action, the EPA is making an interim final determination based on that proposed approval. The effect of this interim final determination is that the imposition of sanctions that were triggered by the EPA's December 8, 2023 disapproval are now deferred. Although this action is effective on publication, the EPA will take comment on this interim final determination.