Soil vapor intrusion is caused when the fumes from underground naturally-occurring and anthropogenic chemicals migrate inside a building. Vapor-forming chemicals may include volatile organic compounds (VOCs), semi-volatile organic compounds (sVOCs), elemental mercury, and certain chemicals common in the environment such as polychlorinated biphenyls (PCBs) and pesticides. Particular chemicals of concern include petroleum hydrocarbons, such as benzene, ethylbenzene, xylene, toluene, and naphthalene; as well as chlorinated solvents, such as trichloroethylene (TCE), tetrachloroethylene (PCE or PERC), methylene chloride, and vinyl chloride.
Numerous states have enacted laws, regulations, and/or policy standards concerning the soil vapor intrusion pathway for chemicals that can migrate from contaminated soils and groundwater into indoor air from the subsurface. These measures are designed to protect the public’s health, and in some cases worker safety, although the method of regulation and the standards set vary from state to state.
This map identifies and displays a cross-sectinal dataset of key features of how states address the volatilization of chemicals of concern from subsurface soils to indoor air during the soil vapor intrusion pathway across all 50 states and the District of Columbia as of August 1, 2017.
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