EPA determined that hydrofluoroolefin-1234yf is an acceptable substitute for chlorofluorocarbon-12, an ozone-depleting substance, in motor vehicle air conditioning for new passenger cars and light-duty trucks.

EPA approved the Gila River Indian Community's tribal implementation plan to regulate air quality within the exterior boundaries of the tribe's reservation.

EPA stayed the requirement for chemical manufacturing area sources to comply with the Title V permit program during reconsideration of certain NESHAP provisions.

EPA finalized amendments to the NESHAPs for existing stationary spark ignition reciprocating internal combustion engines.