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Soil Gas Vapor in the Workplace

If worker right-to-know laws are intended to require employers to inform their employees of the specific hazards based on specific chemicals to which their employees are exposed in the workplace, soil gas vapor regulation is intended to fill a significant gap, namely the wide range of pollutants that employers typically cannot know about and protect employees from. Soil gas vapor regulation is designed to set forth remedial steps that are required to be taken by property owners (who may or may not be the office building employers) in the face of uncontrollable and sometimes unknown sources of contamination in groundwater and soil beneath the building.

Vapor intrusion refers to the process by which volatile chemicals move from a subsurface source into the indoor air of overlying or adjacent residential or commercial buildings. Soil vapors can enter buildings in two different ways: first, in relatively rare cases, vapor intrusion is the result of groundwater contamination which enters basements and releases volatile chemicals into the air. In most cases, however, vapor intrusion is caused by contaminated vapors migrating through the soil directly into basements or foundation slabs. Historically, vapor intrusion was thought to be connected to a source of very shallow contaminants. We now know that this assumption was incomplete. Today, ranking systems have been developed to account for the two different sources of contaminated vapors. Contaminated soil vapor is not the only possible source of volatile chemicals in door air.

As previously discussed on our blog, VOCs (volatile organic compounds) are found in many products in building components or office equipment in office buildings, such as paints, glues, aerosol sprays, new carpeting or furniture, refrigerants and recently dry-cleaned clothing; for this reason, accurately identifying sources of common VOCs and thus accurately assigning liability can be far from easy.


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