On November 20, 2025, the California Air Resources Board Executive Officer, Steven S. Cliff, signed an Executive Order adopting the South Coast Air Quality Management District’s South Coast Air Basin Contingency Measure SIP Revision for the 70 parts per billion 8-Hour Ozone Standard. Over the last few years, the California Air Resources Board and the South Coast Air Quality Management District have worked closely with the U.S. Environmental Protection Agency to develop contingency measures to meet Clean Air Act contingency requirements. The Clean Air Act requires that State Implementation Plans include contingency measures to be triggered if an area fails to attain a federal standard by an applicable deadline, meet a reasonable further progress milestone requirement, or submit a milestone compliance demonstration. The California Air Resources Board and the South Coast Air Quality Management District developed South Coast Air Basin Contingency Measure SIP Revision for the 70 parts per billion 8-Hour Ozone Standard to meet Clean Air Act contingency requirements.
