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…

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 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…

A California court overturned a small claims court's grant of damages in favor of a woman who filed suit against an automobile manufacturer for making fraudulent claims about her hybrid car…

A district court held that EPA does not have a mandatory duty to review and, if necessary, promulgate new PSD rules for ozone simply because the NAAQS for ozone has been revised. The history of…

A district court held that an environmental group may go forward with its CAA citizen suit against EPA for failing to promulgate by November 15, 2000, regulations to reduce hazardous air…

The Fifth Circuit vacated EPA's disapproval of three Texas regulations that provide for a standardized permit for minor new source review (NSR) pollution control projects that reduce or…