In the late 1970s, three hazardous waste sites, Love Canal in New York, Valley of the Drums in Kentucky and Times Beach in Missouri, were discovered. At each of these sites, hazardous wastes had been dumped several years before the sites were found. Unfortunately, the Resource Conservation and Recovery Act (RCRA) did not cover wastes that were abandoned or uncontrolled.

On Dec. 11, 1980, Congress passed the Comprehensive Environmental Response Compensation and Liability Act (CERCLA [pronounced "sir-cla"]), and better known as Superfund. CERCLA created a federal Trust Fund through a tax on the chemical and petroleum industries. This Trust Fund or Superfund was to be used to clean up uncontrolled or abandoned hazardous waste sites when potentially responsible parties could not be identified or located. The fund also covered accidents, spills and other emergency releases of pollutants and contaminants into the environment. The Act gave the U.S. Environmental Protection Agency (EPA) the power to search for the responsible parties, assure they cooperate in the cleanup and recover costs once the cleanup was complete. The Superfund was capitalized with $1.6 billion.

CERCLA was amended by the Superfund Amendments and Reauthorization Act (SARA) on Oct. 17, 1986. Initially it was believed that there were only a few Superfund sites, requiring about five years to clean up. However, many more sites were identified nationwide. SARA made several important changes and additions to the program, including creating new enforcement authorities and settlement tools and increasing the size of the Trust Fund to $8.5 billion. SARA also required EPA to revise the Hazard Ranking System (HRS) to make sure that it correctly evaluated the degree of risk the uncontrolled hazardous waste site posed to human health and the environment. The HRS “score” is the primary method used to place uncontrolled waste sites on the National Priorities List (NPL). A site must be on the NPL to receive money from the Trust Fund for cleanup action.

The Missouri Department of Natural Resources' Hazardous Waste Program works with EPA to investigate and oversee the cleanup of Superfund sites in Missouri. Information on Superfund sites can be found on EPA's Superfund Enterprise Management System (SEMS). Detailed information about the cleanup actions on Missouri's NPL sites can be found here.

Missouri also passed a law that requires the department to maintain, and make available to the public, a registry list of all abandoned or uncontrolled hazardous waste disposal sites in the state. Each year an annual report on all Missouri abandoned or uncontrolled hazardous waste sites is sent to the Missouri Hazardous Waste Management Commission, the Missouri General Assembly, the governor and the governing body of each Missouri county where a site is located.