On April 16, the United States Environmental Protection Agency (“EPA”) took a significant step towards finalizing its long-pending guidance on the evaluation and response to vapor intrusion from contaminated soil and groundwater, releasing an updated draft of the guidance for public comment. The guidance, which EPA first released in draft form in 2002, is anticipated to have significant impacts for the owners, operators, and potential purchasers of sites contaminated by solvents, petroleum, and other volatile organic compounds (“VOCs”), as well as any parties responsible for such contamination.

What sites are at risk of vapor intrusion?
Vapor intrusion, the migration of hazardous vapor from contaminated soil or groundwater into buildings, is of greatest concern at sites contaminated by VOCs , such as the chlorinated solvents perchloroethylene (“PCE” or “Perc”) and trichloroethylene (“TCE”), as well gasoline constituents. Vapor can enter a building because of cracks in the foundation, openings around pipes or electrical wires, and heating and ventilation systems that decrease indoor air pressure, creating conditions that draw in vapor.

How have environmental regulators addressed vapor intrusion in the past?
In response to new evidence of human health risks and potential explosion hazards from vapor intrusion, EPA released draft vapor intrusion guidance under the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”) and Resource Recovery and Conservation Act (“RCRA”) in 2002. At the time, EPA stated that “as the state-of-the-science improves, this guidance will be revised as appropriate.”

Over the following decade, however, the draft guidance was neither finalized nor revised, and individual states began to fill the regulatory gaps left by EPA. New York’s Department of Environmental Conservation (“DEC”) and Department of Health issued their own vapor intrusion guidance, and DEC began a formal re-evaluation of hundreds of contaminated sites – many of which had already been remediated and delisted – for new vapor risks. In December 2009, EPA’s Inspector General reported that the absence of final EPA guidance had “[impeded] EPA’s efforts to protect human health at sites where vapor intrusion risks may occur,” and urged EPA to finalize its 2002 draft.

What changes did EPA propose in its revised vapor intrusion guidance?
In response to the Inspector General report, last month EPA released a pre-publication draft of its final vapor intrusion guidance for public review and comment. The updated document incorporates a number of revisions from the 2002 draft, including:

  • A new, online calculator for determining generic and site-specific screening levels –contaminant concentrations where vapor intrusion is believed to present risk and additional investigation or mitigation is warranted;
  • New recommendations for preemptive mitigation and early action at certain sites before a full vapor intrusion analysis is complete;
  • New guidance on the use of deed restrictions and other institutional controls to restrict land uses or activities that could otherwise result in unacceptable exposure to the vapor intrusion pathway
  • A separate guidance document addressing petroleum vapor intrusion from underground storage tanks, which was not covered in EPA’s 2002 guidance.

Who is likely to be impacted by EPA’s new guidance?
EPA’s guidance is specifically addressed to sites being evaluated pursuant to CERCLA and RCRA, and it is expected to influence the scope of remedial investigations, risk assessments, and remedy selection at such sites. Moreover, because many CERCLA sites where remediation is complete must undergo five-year reviews for remedial effectiveness, consideration of vapor intrusion could reveal new public health risks and trigger additional mitigation requirements.

The guidance will also have impacts extending beyond CERCLA and RCRA. Vapor intrusion is an increasingly common topic in environmental due diligence for real estate transactions, and Phase I Environmental Site Investigations often analyze possible vapor intrusion pathways. EPA’s new screening levels and recommended mitigation measures are likely to inform negotiating positions and risk allocation at sites where vapor intrusion is suspected. Vapor intrusion could also give rise to toxic tort liability, with plaintiffs relying upon EPA guidance and other regulatory standards to establish a violation of the defendant’s standard of care. Finally, because vapor intrusion may impose new costs at previously-remediated sites, the guidance could lead more property owners to pursue “reopener” environmental insurance policies covering expenses incurred after a “No Further Action” or “Construction Complete” letter has been issued by state or federal environmental regulators.

How can I submit comments on EPA’s new guidance?
Comments on EPA’s revised vapor intrusion guidance may be submitted online at http://www.regulations.gov/#!docketDetail;D=EPA-HQ-RCRA-2002-0033 through May 24, 2013.
For more information about EPA’s guidance or other issues relating to vapor intrusion, contact Christine Leas or Jonathan Kalmuss-Katz.