Nearly 10 years to the day when EPA issued its Draft Guidance for Vapor Intrusion, EPA is poised to finalize its Final Vapor Intrusion Guidance on or before November 30, 2012. As a result, businesses that build or own property near contaminated sites, such as Brownfield Sites and industrial sites, need to stay aware of how these changes may impact your operations. More and more businesses, for example, will require a vapor barrier or a vapor migration system (active or passive) that diffuses vapors from the building to satisfy EPA’s requirements.
Vapor intrusion refers to the upward and side-ward migration of chemicals that volatilize into buildings that overlie contaminated soils and groundwater plumes through dirt floors and cracks in foundations. EPA and state regulators are concerned that the vapors from the volatile chemicals that can migrate into in the indoor air may pose an unacceptable risk of chronic health effects due to long-term exposures, even when present at extremely low levels.
Sites that present the potential for vapor intrusion include those where there have been spills and releases of the common industrial solvent trichloroethylene (TCE), such as metal parts cleaning and parts washing, degreasing operations, automotive and jet engine cleaning, and electronic and semi-conductor manufacturing, as well as releases and discharges of the industrial solvent perchloroethylene (PCE or PERC) widely used in commercial dry-cleaning operations.
In tandem with the foregoing, EPA is also in the process of preparing a Draft Petroleum Vapor Intrusion (VPI) Guidance for release in November 2012, applicable to locations that housed leaking underground storage tanks of petroleum products such as gasoline, diesel, and jet fuel. Among the most controversial aspects of the Draft PVI Guidance is a recent decision in a June 14, 2012, working draft that doubles the soil separation distance – from 15 feet to 30 feet – between the building and contaminated soil, necessary to biodegrade petroleum vapors so as to ensure vapor intrusion does not occur.