Environmental Due Diligence - EPA Adds Subsurface Intrusion To Superfund Hazard Ranking System

Last week, EPA finalized a rule that will allow it to consider subsurface intrusion (most commonly found as "vapor intrusion") when deciding whether to add a site to the CERCLA National Priorities List ("NPL"). The addition will enable EPA, using its "Hazard Ranking System," to directly consider the human exposure to contaminants that enter building structures through the subsurface environment. The move is designed to allow EPA to evaluate the relative potential risk posed by the uncontrolled release of hazardous substances through the subsurface pathway. According to EPA, "the addition will enable EPA to identify risks posed by subsurface intrusion of hazardous substances into regularly occupied structures for all populations who live and work in areas where the subsurface environment may create exposures."