EPA Elevates Significance of Vapor Intrusion at Contaminated Sites: Comment Period on New EPA Guidance Now Open

April 12, 2011
by MICHAEL C. GROSS and MICHAEL C. NINES
MGKF Special Alert

In a move that could substantially alter remediation approaches at properties where subsurface contaminants may be intruding into indoor air, the United States Environmental Protection Agency ("EPA") is planning to issue its final Vapor Intrusion Guidance by November 30, 2012 ("the Guidance"). The Guidance will supersede the current 2002 EPA Subsurface Vapor Intrusion Guidance ("OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils").

Strategic consideration of vapor intrusion issues is critical in conjunction with the proposed redevelopment of any property with environmental impacts. In addition, vapor intrusion issues frequently emerge in the content of refinancing activities, even for sites which had been previously closed out under state remediation programs. Failure to prospectively address vapor intrusion concerns at the development stage can result in costly retrofits and even toxic tort liability. Properties identified by EPA as posing vapor intrusion risks include current and former manufacturing and chemical processing plants, warehouses, landfills, coal gasification plants, train yards, dry cleaners, and gas stations.

In finalizing the Guidance, EPA plans to incorporate recommendations of its Inspector General, including updating toxicity values, use of multiple lines of evidence, addressing risk from petroleum hydrocarbons, evaluating how the guidance applies to Superfund Five-Year reviews, assessing when preemptive mitigation is appropriate, reviewing operations and maintenance of vapor intrusion mitigation systems, and considering when institutional controls and deed restrictions in vapor intrusion scenarios are appropriate. Changes to the methodology for indoor air assessments focusing on air sampling are anticipated. EPA is seeking public comment for consideration during the development of the Guidance and is accepting written public comments until May 14, 2011.

In a related effort, EPA is collecting public comments on potential revisions to the Hazard Ranking System ("HRS") for National Priorities List ("NPL") sites to account for vapor intrusion pathways in Superfund cleanups. In doing so, EPA is weighing the addition of vapor intrusion as a component of the HRS scoring system. Accordingly, certain non-NPL contaminated sites which did not otherwise qualify for placement on the NPL under the current system, may qualify for placement on the NPL under a new proposal to include vapor intrusion.

Clients seeking to submit comments on the Guidance or for questions concerning issues related to vapor intrusion, please contact Michael Gross (mgross@mgkflaw.com; 484-430-2321) or MGKF technical consultant Michael Nines (mnines@mgkflaw.com; 484-430-2350).