Two citizen groups, the Housatonic River Initiative and the Housatonic Environmental Action League (“Citizen Groups”), have jointly petitioned for review of a corrective action permit that imposes remediation requirements for polychlorinated biphenyls (“PCBs”) contaminating the Housatonic River in Massachusetts and Connecticut. The U.S. Environmental Protection Agency’s Region 1 office (“Region”) issued the permit to the General Electric Company under the Resource Conservation and Recovery Act (“RCRA”).