Proposed rule · 2025-19884

Approval of Clean Air Plans; San Joaquin Valley, California; Contingency Measures for 1997 Ozone Standards

The Environmental Protection Agency (EPA) is proposing to approve under the Clean Air Act (CAA or "Act") a state implementation plan (SIP) submission from the State of California as meeting the attainment-related contingency measure requirements for the 1997 ozone national ambient air quality standards (NAAQS or "standards") in the San Joaquin Valley, California, ozone nonattainment area. The SIP revision is titled "California Smog Check Contingency Measure State Implementation Plan Revision" (Released: September 15, 2023) ("Smog Check Contingency Measure SIP"). The EPA's proposed approval relies on the previously-approved contingency measure for the 1997 ozone NAAQS for the San Joaquin Valley and the justifications for not adopting additional contingency measures that provide for the recommended amount of emissions reductions for such measures. Based on the proposed approval, the EPA is also proposing to determine that the State of California has fulfilled the commitment made by the State in connection with a previous approval action to develop, adopt, and submit attainment contingency measures for the San Joaquin Valley for the 1997 ozone NAAQS meeting the requirements of the CAA.