The production of hazardous waste accompanied the development of industry in Chicago. From slaughterhouse activities in the nineteenth century to metal-based factories in the twentieth, the byproducts created by these various industrial enterprises resulted in extensive health threats. Lead-containing dust, asbestos, and unsafe levels of arsenic and cyanide were just a few of the toxins generated. Until the 1920s, however, health officials focused their attention on bacteriological dangers rather than the byproducts of industrialism. Even then, they framed the discussion in terms of industrial waste's risk to water rather than to human life. The environmental movement began to address these hazardous waste sites starting in the late 1940s with the mandate for using sanitary landfills, but the absence of a standardized classification system for industrial waste stymied its efforts. The reinvigoration of the environmental movement in the late twentieth century led Illinois to prohibit open waste dumping in 1966. In 1969 Chicago compelled industries to pretreat pollutants prior to release.

Chemical and steel companies remained important sources of employment in Chicago until the 1960s, when hundreds of factories began to relocate to other regions. Those that relocated at that time, before there were legal constraints upon abandoning wastes, left many toxic, vacant areas in their wake. By the end of the twentieth century, over two hundred of the worst historical waste sites were being monitored and cleaned up through federal legislation. Thousands of other active sites that generated, transferred, stored, or disposed of hazardous wastes (or were more recent recipients of this waste) were under federal or state scrutiny.

Don Coursey