When a possible new hazardous substance site is discovered, the department's Superfund Site Assessment Unit is assigned to perform the investigation. New sites are discovered in many ways, including citizens reporting concerns.
Pre-CERCLA Site Screening
A Superfund project manager is assigned to the site and the begins the investigation, usually with a Pre-CERCLA Site Screening, to determine whether there is a release of a hazardous substance into the environment. The project manager visits the site and gathers historical and other available information about any known or suspected hazardous substance releases and the current site conditions. The investigation may include limited environmental sampling. If a release of a hazardous substance is documented or suspected, the site is recommended for entry onto the U.S. Environmental Protection Agency's (EPA) list of Superfund active sites for additional investigation.
Preliminary Assessment
During a Preliminary Assessment investigation, the project manager builds on the information gathered during the Pre-CERCLA Site Screening. The project manager attempts to identify all the suspected sources of contamination and the potential for the hazardous substances to move from those sources into the soil, groundwater, surface water, sediment or air. The project manager also evaluates who lives nearby that may be affected by those hazardous substances. This information is used to evaluate whether the site poses a threat to human health or the environment or whether further investigation is needed.
Site Inspection
The Site Inspection includes collecting and analyzing waste and environmental samples, such as air, groundwater, surface water and soil. This information is used to determine if hazardous substances are present and, if so, the type and amount of waste released. Information about Missouri Superfund sites under investigation can be found in EPA's searchable public access Superfund Enterprise Management System database.
Site Ranking
Information about the site that was collected in the Site Inspection investigation is used to evaluate the potential risks posed by the site. The project manager uses the Hazard Ranking System to numerically “score” the site. Sites that score at or above an established number of points qualify for cleanup under Superfund and are proposed for listing on EPA’s National Priorities List, a list of the most serious sites in the nation identified for long-term cleanup.