The D.C. Circuit vacated an EPA memorandum directing regional air districts to apply different criteria when making source determinations in its Title V or new source review (NSR) permitting decisions for facilities located in areas within the jurisdiction of the U.S.

A district court dismissed an environmental group's citizen suit in which it alleged a power company was attempting to construct a major modification of its coal-fired power plant in Illinois without a PSD permit in violation of the CAA.

The D.C. Circuit dismissed teenagers' lawsuit against the federal government for failing to cap greenhouse gas emissions. Invoking the federal question statute, 28 U.S.C.

A district court held that a Hawaiian county illegally discharged wastewater into the ocean through groundwater injection wells in violation of the CWA.

A district court held that an environmental group lacked standing to challenge a U.S. Army Corps of Engineers permit issued to an oil company to fill certain wetlands in the National Petroleum Reserve–Alaska for a future drill site.

A district court upheld a U.S. Army Corps of Engineers permit issued under CWA §404 for a railroad extension project in an area surrounded by wetlands. Two functional assessments were prepared for the project.

A district court held that mining companies discharged excessive amounts of ionic pollution, measured as conductivity, into the waters of West Virginia in violation of their federal NPDES and state surface mining permits.

The U.S. Supreme Court held that CERCLA §309 does not preempt a state's statute of repose. The case arose after property owners filed suit against a manufacturing company for alleged groundwater contamination stemming from chemicals stored on property the company sold 24 years ago.