The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, was enacted by Congress in 1980. This law created a tax on the chemical and petroleum industries and provided broad Federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment.

In the case of western Montana, the Superfund law paved the way for the remediation and restoration of much of the western Montana environment that was damaged by over a century of mining and smelting. Mining-related environmental damages in western Montana are categorized by site and organized by the EPA into different “operable units.” The urban Butte area contains several such operable units. Silver Bow Creek represents another operable unit, referred to by the EPA and state Department of Environmental Quality as the Streamside Tailings operable unit. The situation in western Montana is complicated by the fact that these different operable units interact with one another in different ways.

For more information on Superfund, visit the EPA CERCLA website.