In Central Arizona Water Conservation District v. EPA, 990 F.3d 1531 (9th Cir. 1993), the Court held that the petitioners-a water district and four related irrigation districts-had standing to challenge an Environmental Protection Agency (EPA) regulation that required a generating station to reduce sulfur dioxide emissions by 90%. Id. at 1537-38. The Court held the petitioners, as direct customers of the generating station, established an injury in fact where they were contractually required to repay the generating station the major portion of costs relating to the stations compliance with the EPA order. Id. at 1534, 1537-38.