Vapor Intrusion Guidance Continues to Take Form With the Release of EPA’s Final Draft Guidance

The United States Environmental Protection Agency (“EPA”) recently released its long-awaited final vapor intrusion draft guidance (“Final VI Guidance”). The nearly 200-page document establishes a complex framework for assessing vapor intrusion from analyzing key factors; making risk management decisions; and implementing, monitoring and terminating mitigation strategies and is intended to be used at any site that is being evaluated under CERCLA, RCRA, EPA’s brownfield grantees, or state agencies with delegated authority. The Final VI Guidance supercedes all prior EPA guidance documents addressing vapor intrusion assessment and mitigation including the 2002 Draft Vapor Intrusion Guidance, but takes into account the public comments submitted from 2002 through 2012 and the recommendations of the Office of Inspector General (OIG).

In addition to the Final VI Guidance, which applies generally to petroleum hydrocarbons, EPA released its companion Guidance For Addressing Petroleum Vapor Intrusion At Leaking Underground Storage Tank Sites (“PVI Guidance”), which focuses specifically on petroleum hydrocarbons released from underground storage tanks. For these situations, the guidance recommends that owners and operators assess any immediate threat to safety, conduct a site characterization and develop a conceptual site model, delineate a lateral inclusion zone, identify preferential transport pathways within the inclusion zone, sample if light non-aqueous phase liquid (“LNAPL”) exists within 15-feet of an underlying building, and mitigate as appropriate.

“When final, these guidance documents will help ensure vapor intrusion exposure assessment and mitigation actions to protect human health are undertaken in a technically, scientifically and nationally consistent manner,” stated Richard Kapuscinski, a senior official in EPA’s Office of Superfund Remediation and Technology Innovation, in a memorandum announcing the Final VI Guidance release.

The public’s reaction to the new guidance documents remains to be seen. Some early responses have raised concerns about escalating costs relating to the extensive testing required by the new guidance. Others have questioned EPA’s ability to reopen old sites where remediation has been deemed complete, but were evaluated under methods made defunct by the new guidance.

EPA is seeking public comment on the drafts, which may be submitted here until May 24, 2013. To date, over 81 public comments have been posted to the website relating to VI guidance. Other EPA technical documents relating to vapor intrusion, including the Vapor Intrusion Screening Level (“VISL”) Calculator and the Superfund Five-year Review Guidance may be found at the Office of Solid Waste Emergency Response website.

State practitioners should also be mindful of the federal guidelines. New Jersey recently issued new vapor intrusion screening levels to reflect the changes in the federal VISL. Thus, changes in the federal guidance may trigger changes in the state guidance. This blog will certainly comment on any new developments.

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