The Sixth Circuit vacated EPA's determination that a natural gas operation's plant and production wells separately located within a 43-square-mile area constitute a single stationary…

The Fifth Circuit upheld an EPA rule partially approving and partially disapproving revisions to Texas' SIP concerning civil penalties for excess emissions resulting from startup, shutdown,…

The D.C. Circuit dismissed petitions challenging EPA's primary NAAQS for sulfur dioxide (SO2). The petitioners—several states, state regulatory agencies, corporations, and industrial…

The D.C. Circuit denied petitions challenging EPA's one-hour primary NAAQS for nitrogen dioxide (NOx). The new one-hour primary NAAQS requires that “the three-year average of the annual 98th…

A California appellate court upheld a local air district rule that requires manufacturers of consumer paint thinner and solvent products to limit the use of ozone-forming volatile organic…

The D.C. Circuit upheld four EPA rulemakings governing greenhouse gases. EPA issued the rules following the U.S. Supreme Court's decision in Massachusetts v. EPA, 549 U.S. 497 (2007), in…

The California Supreme Court upheld an air district's technology-forcing rules that limit certain pollution-causing substances in paints and coatings. A paint association argued that the…

The Fifth Circuit upheld EPA's decision to disapprove certain revisions to Texas' SIP. EPA disapproved the revisions concerning the state's "qualified facilities program…

The D.C. Circuit vacated an interim final rule issued by EPA that would allow manufacturers of heavy-duty diesel engines to pay nonconformance penalties in exchange for the right to sell engines…

The Sixth Circuit held that the CAA's citizen suit provision does not allow an environmental group to file suit to compel the state of Ohio to administer a particular federal CAA regulation…