Human Exposure in Superfund, Explained

What does EPA mean when it says that human exposure is or is not under control at a Superfund site?

EPA’s Superfund program places sites on the National Priorities List when they require further investigation due to potential risk to human health or the environment. When these investigations find contamination that poses such risks, EPA ensures the sites get cleaned up. As an indication of the risk a site may pose to the public, EPA places it into one of three categories:

Human Exposure Under Control: This category describes sites where EPA can verify that the entire site no longer poses a risk to human health. This is generally because EPA has installed access controls that prevent people from coming onto the site, or EPA has cleaned the site up to exposure levels that do not adversely affect people’s health. Currently, this designation describes 81 percent of the assessed sites.

Human Exposure Not Under Control: This describes sites where contamination is present that could affect human health. This includes some sites where EPA has not yet begun cleanup. But it also includes sites where EPA has already done substantial cleanup work. For example, this includes sites where cleanup is partially complete but people may be exposed to contamination somewhere within a site’s boundaries. At sites where EPA finds contamination that poses an imminent human health or environmental risk, EPA will use its Superfund removal authorities to address this risk and protect the public.  

This designation, which describes only 7 percent of sites, does not necessarily mean that people are being exposed, only that there is potential. An example of such a site would be one with lead-contaminated soil where EPA has cleaned up soil at several hundred residences, significantly reducing residents’ exposure to lead in soil. But, if EPA is still cleaning up additional properties, the work is not yet complete and residents may be exposed. In this case, EPA would describe the site as Human Exposure Not Under Control.

Insufficient Data to Determine Human Exposure: This statement is used when EPA lacks enough information to determine whether people are being exposed to contamination. In this case, EPA needs to complete its investigation as to what contamination exists, where it is located, and how it could adversely affect people. Only 12 percent of sites meet this description.

Typically, sites with insufficient data are those that are at the beginning of the assessment and cleanup process after being placed on the National Priorities List. One example of information needed is at a site where people are catching and eating fish from a nearby river with contaminated sediments. EPA needs to test the fish to determine if they are contaminated at levels that could affect the health of those consuming them.

EPA makes every effort to clean up Superfund sites as quickly as possible so affected communities can put the legacy of contamination behind them and move on with the task of revitalization. EPA will continue working with the utmost diligence until all Americans living near Superfund sites have the protection they deserve.