The US EPA is working toward a proposed rule to add a new screening component (subsurface intrusion (SSI) component) to the Hazard Ranking System (HRS) that would allow sites with vapor intrusion contamination to be evaluated for placement on the National Priorities List (NPL).
The subsurface intrusion component would expand the number of available options for EPA and state and tribal organizations performing work on behalf of EPA to evaluate potential threats to public health from releases of hazardous substances, pollutants, or contaminants. This addition will allow an HRS evaluation to directly consider human exposure to hazardous substances, pollutants, or contaminants that enter regularly occupied structures through subsurface intrusion in assessing a site’s relative risk, and thus, enable subsurface intrusion contamination to be evaluated for placement of sites on the NPL. The agency is not considering changes to the remainder of the HRS except for minor updates reflecting changes in terminology. Read more ->Share