The Ninth Circuit held that EPA did not act arbitrarily and capriciously when it disapproved in part Arizona's regional haze SIP and issued a replacement federal implementation plan (FIP) in…

The Third Circuit vacated and remanded EPA's approval of Pennsylvania's 2014 regional haze SIP. CAA §169A requires states to evaluate the impact that emissions from certain sources of…

The Seventh Circuit upheld EPA's approval of revisions to Illinois' SIP, thereby rejecting challenges raised by Indiana. Indiana argued that the relaxation of Illinois' vehicle…

The Ninth Circuit denied petitions for review challenging EPA's promulgation of 40 C.F.R. §52.245, a regulation that revised the scope of a previous EPA decision, after the Agency determined…

The Ninth Circuit denied a petition for review challenging EPA's approval of a revision to California's SIP that authorized the San Joaquin Valley air pollution control district to…

The Ninth Circuit granted in part and denied in part petitions for review challenging EPA's federal implementation plan to reduce regional haze at two power plants in Montana. The owner and…

The D.C. Circuit denied petitions for review challenging EPA's disapproval of a revision to Kansas' proposed SIP revision for the 2006 fine particulate matter (PM2.5) NAAQS. EPA…

The Ninth Circuit held that EPA violated the CAA when it approved California SIPs concerning NAAQS for ozone and fine particulate matter in the San Joaquin Valley. The SIPs relied on state-adopted…

The Ninth Circuit denied community groups' petition for review challenging EPA's approval of revisions to California's SIP concerning air emissions from pesticides, known as the…

The Ninth Circuit denied an environmental group's petition challenging EPA's approval of a revision to California's SIP. The revision provided alternative "not less stringent…