On June 11, EPA released two long-awaited guidance documents on
addressing the potential for vapor intrusion at contaminated
sites. Vapor intrusion is the potential for vapors from
groundwater contamination to enter occupied buildings. One
guidance document, EPA's "Technical Guide for Assessing
and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor
Sources," applies to all sites being investigated under
cleanup programs such as Superfund, RCRA corrective action, and
state-led Superfund sites. It applies to contaminants other
than petroleum, to mixed petroleum and other contaminant sites, and
to petroleum contamination sites other than underground storage
tanks (USTs). It can be found here. The other guidance,
EPA's Technical Guide for Addressing Petroleum Vapor Intrusion
At Leaking Underground Storage Tank Sites," applies to sites
involving petroleum contamination from USTs, and can be found
here.
