EPA's Vapor Intrusion Guidance
This article provides a brief update to the status of the U.S. Environmental Protection Agency’s (EPA’s) VI Guidance for use at Federal Superfund Sites. The current federal guidance document is the 2002 OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils, which can be found here. EPA is making progress toward finalizing its guidance and expects to publish interim guidance as soon as this year.
One of the most problematic issues for EPA is identifying the toxicological values to use for certain volatile organic compounds (VOCs). EPA is currently using a variety of values, some developed at the state level, to establish VI standards for specific sites. As a result, there is no consistency between the various EPA regions in its application of VI standards. EPA is currently completing its toxicological reviews for certain VOCs and with these values, it will be in a position to issue interim guidance.
In addition, EPA is evaluating how risks from petroleum hydrocarbon vapors should be addressed. EPA hopes to include guidance on this issue in its interim guidance. Finally, EPA will consider how the guidance should be applied during five-year reviews and when institutional controls and deed restrictions may be used to address VI issues.