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 promulgated new source performance standards and emission guidelines for commercial and industrial solid waste incineration units.

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