The Ninth Circuit upheld an EPA federal implementation plan (FIP) under the CAA that replaced rejected portions of the Arizona SIP concerning air quality at federal parks and forests. In 2011, Arizona submitted a SIP to EPA for approval. EPA disapproved certain aspects of Arizona’s SIP concerning ...

The Tenth Circuit held that FWS has the authority under the Commerce Clause to regulate the take of the Utah prairie dog. A group of property owners challenged FWS's authority to use the ESA to prohibit take of the Utah prairie dog, an intrastate species, on nonfederal land. A district court granted...

A district court ordered EPA to complete overdue assessments of 13 sources of hazardous air pollutants. In 2016, environmental groups sued the Agency over a failure to meet CAA requirements that the standards for air pollutants be reviewed within eight years to account for technology improvements. T...