The U.S. Supreme Court case City of Chicago, et al. v. Environmental Defense Fund et al., 1993 revolved around the interpretation of the Resource Conservation and Recovery Act (RCRA). The city of Chicago had been mixing fly ash, a byproduct from municipal incinerators, with water and other substances to create a solid block that was then used as daily landfill cover. However, the Environmental Defense Fund argued this process violated RCRA's prohibition on "open dumping" because hazardous waste was being placed into or on any land or water where it could pose environmental hazards. The Supreme Court ruled in favor of the Environmental Defense Fund stating that once fly ash is no longer serving its original purpose in an ongoing industrial operation but instead discarded for final disposal constitutes 'discarded material' within meaning of statutory definition of 'solid waste,' thus subjecting it to regulation under Subtitle C when such waste exhibits characteristic hazardousness.

In the dissenting opinion for City of Chicago, et al. v. Environmental Defense Fund et al., Justice Blackmun argued that the majority's interpretation of Resource Conservation and Recovery Act (RCRA) was too narrow and failed to consider its broader environmental objectives. He contended that Congress intended RCRA to regulate all facilities dealing with solid waste, including municipal incinerators like those in question in this case. According to him, exempting these facilities from regulation would undermine RCRA’s goal of promoting environmentally sound methods for disposal of hazardous wastes by allowing potentially harmful substances into the environment without proper oversight or control measures in place. Furthermore, he criticized the majority's reliance on a single sentence within a House Report as definitive evidence of Congressional intent while ignoring other legislative history suggesting a more expansive reading.