U.S. EPA Considers Adding Vapor Intrusion to Superfund Site Listing Criteria
By Andy Bowman, Attorney, Bingham Greenebaum Doll LLP
The U.S. EPA is seeking input from the public whether the Hazard Ranking System (HRS) used to evaluate sites for inclusion on the National Priorities List (NPL) should include an evaluation of the potential exposure of building occupants to vapor intrusion of contaminants. The HRS is used to score the relative risks posed by contaminated sites to determine if the site warrants further investigation. Sites scoring 28.50 or greater are placed on the NPL, more commonly known as the “Superfund List.”
A May 2010 General Accounting Office report found that there may be contaminated sites with unacceptable human exposures that did not score high enough for inclusion on the NPL without taking into account vapor intrusion. HRS scoring currently evaluates four exposure pathways: groundwater migration, surface water migration, soil direct contact and ambient air migration.
U.S. EPA is taking comments until April 15, 2011. More information can be found in 76 Federal Register 5370 (January 31, 2011) and at www.epa.gov/superfund/sites/npl/hrsaddition.htm.
U.S. EPA is also preparing new guidance on vapor intrusion. Information can be found at www.epa.gov/oswer/vaporintrusion/.