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…

A district court dismissed environmental groups' CAA citizen suit against a crude oil transloading facility for constructing and operating the facility without a prevention of significant…

The D.C. Circuit dismissed petitions challenging EPA's authorization of California regulations intended to reduce emissions of particulate matter and oxides of nitrogen from in-use nonroad…

The Fourth Circuit granted EPA's petition for a writ of mandamus to preclude an energy company from deposing EPA Administrator Gina McCarthy in a lawsuit seeking to compel EPA to evaluate the…

A district court dismissed environmental groups' CAA citizen suit against EPA for failing to respond to their 2011 petition concerning ammonia gas pollution. In 2011, the groups petitioned…

The D.C. Circuit dismissed a truck association's lawsuit against EPA challenging California's tractor-trailer emission rules. The association argued that the state regulations…

The D.C. Circuit upheld EPA's designation of Yellowstone County, Montana, and Wayne County, Michigan, as "nonattainment" under the sulfur dioxide (SO2) NAAQS. Two petitioners—an…

The Sixth Circuit held that the CAA does not preempt property owners' state common-law tort claims against a whiskey distillery for excess ethanol emissions that allegedly caused "…

The Sixth Circuit held that the CAA does not preempt property owners' state common law tort claims against a nearby power plant for allowing ash, dust, and coal combustion by-products to blow…

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…