On March 25, the U.S. Court of Appeals for the Fifth Circuit said the Environmental Protection Agency (EPA) acted under its statutory authority when it partially approved of Texas’s revised implementation plan for emission standards for the startup, shutdown, and maintenance of facilities. The EPA had approved the affirmative defense for unplanned startup, shutdown, and maintenance but had disapproved of the affirmative defense for planned activities. Luminant Generation Co. and environmental groups petitioned the court.