Soil vapor studies have been used by environmental professionals for more than four decades
to locate sources of volatile organic compounds (VOCs) in the subsurface and to track the
migration of contaminated groundwater. As the tools used to collect and assess soil vapor
improved, it became apparent that these vapors were migrating into inhabited buildings through
processes commonly referred to as vapor intrusion.
Vapor intrusion assessments have revealed that chemical vapors released from contaminated
sites can affect a much wider area than previously thought, impacting the indoor air quality of
nearby homes, businesses, or entire neighborhoods. Many times, these vapors have been
found to migrate through preferential pathways such as sewer lines and utility corridors.
Vapor intrusion is insidious because some of the most dangerous (and common) VOCs
associated with contaminated sites are not detectable by humans at concentrations that can
lead to irreversible harm. The risks to human health and the environment associated with
contaminated soil and groundwater can be easily mitigated by eliminating the direct contact
pathway through land use restrictions (barriers, caps, and restrictive covenants) or alternative
drinking water supplies. However, we all need to breathe the air within the indoor spaces we
inhabit. Because of this, vapor intrusion mitigation must be completed one building at a time.
You can’t mitigate unless you investigate. You must investigate to protect human health.