The D.C. Circuit held that EPA did not violate the CAA by modifying, without notice and comment, its prior understandings of how to measure a proposed transportation project’s impact on ambient…

A district court ordered EPA to issue infrastructure requirements for the 2012 fine particulate matter NAAQS for five states within 90 days. In 2015, New Jersey, Pennsylvania, Washington, Illinois…

A district court denied EPA's request to amend a 2012 consent decree obligating the Agency to approve state regional haze plans. In 2011, environmental groups sued the Agency to compel it to…

The Ninth Circuit upheld a 2014 EPA settlement that required the Agency to set a phased schedule for it to issue air quality designations as required by a 2010 sulfur dioxide NAAQS. In 2013, when…

The Tenth Circuit rejected EPA's decision to deny an oil company's request for an exemption from the blending requirement under the Renewable Fuel Standards Program of the CAA. In 2005,…

The D.C. Circuit held that EPA overstepped its authority under the CAA when it banned the use of hydrofluorocarbons (HFCs) in products. In 2015, EPA issued a rule that restricted the manufacture…

The D.C. Circuit held that EPA must justify emissions limits set for certain hazardous air pollutants. The CAA requires EPA to set limits for seven different hazardous air pollutants (HAPs). In…

The D.C. Circuit held that EPA must continue to enforce methane emissions regulations implemented by the previous administration. In 2016, an EPA regulation required oil and gas companies to find…

The Fourth Circuit held that it does not have jurisdiction to determine whether EPA violated the CAA when the agency failed to conduct continuing evaluations of potential loss or shifts of…

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,…