What is the key question EPA tries to answer through a site investigation?

Findings of the site investigation determine what hazardous substances may be present, whether they may be released to the environment, and any potential threat to human health. 

Information about the site that is collected in the preliminary assessment and site investigation phase helps EPA to evaluate the risks posed by the site using what is called the Hazard Ranking System (HRS). The HRS is a screening tool used by EPA to evaluate the potential threat to human health and the environment posed by an actual or potential release of hazardous substances. EPA will consult with Pennsylvania Department of Environmental Protection (PADEP) and both agencies will evaluate options to address potential risks to human health, which would include proposing the site for inclusion on the National Priorities List (or Superfund List) for long-term investigation and possible cleanup.