On May 2, 1994, the Supreme Court issued its decision in City of Chicago v. Environmental Defense Fund, Inc. 114 S.Ct. 1588 (1994). In so doing, the Court held that, although municipal waste-to-energy (WTE) facilities that burn household wastes alone, or in combination with nonhazardous wastes from industrial and commercial sources, are exempt from regulation as a hazardous waste treatment, storage, or disposal facility under Subtitle C of the Resource Conservation and Recovery Act (RCRA), the ash that they generate is not exempt. The Court, however, did not specify the point at which the ash generated by the WTE facility becomes subject to Subtitle C of RCRA. EPA is responding to numerous requests for resolution of this issue by announcing today that it interprets Sec. 3001(i) of RCRA to first subject the ash generated by a WTE facility to RCRA Subtitle C when it exits the combustion building following the combustion and air pollution control processes.