Vapor Intrusion (VI): The Silent and Invisible Risk
Vapor intrusion (VI) can occur on sites where contaminants are present. Vapor intrusion occurs when vapors from chemicals in contaminated groundwater or soil migrate through subsurface soils and preferential pathways to impact the indoor air quality of overlying or adjacent buildings. Contaminants migrate into the indoor air of a building through pathways, including floor cracks, utility penetrations in a basement or from unlined crawl spaces. The chemical vapors that have migrated into the indoor air are often trapped in a building by the structure’s walls and roof. Vapors can increase in concentration over a prolonged period as they accumulate in the indoor air.
The risks associated with vapor intrusion include adverse intermediate, chronic, and acute health effects, and potential fires and explosions, according to the Agency for Toxic Substances and Disease Registry (ATSDR). There is also the intangible impact where impacted indoor air quality can cause anxiety among building occupants and property owners.
Some of the more typical sites with vapor intrusion include gas stations, dry cleaners, or operations that use metal parts degreasers. Common chemicals resulting in vapor intrusion include benzene, trichloroethylene (TCE), tetrachloroethylene (PCE), vinyl chloride.
According to the Interstate Technology Regulatory Council (ITRC), vapor intrusion, which has become a significant environmental issue for regulators, industry leaders, and concerned residents, requires three components:
A source
An inhabited building
A pathway from the source to the inhabitants
Vapor intrusion is a complex problem with many variables, which requires an experienced environmental professional to assess and manage a potential or identified VI pathway. Point Blue provides expertise for the identification, mitigation, and remediation of vapor intrusion pathways and sources. After a vapor intrusion pathway is confirmed, there are typically two options: mitigation and remediation, though not exclusive of each other. Mitigation is the process of interrupting the vapor intrusion exposure pathway so that the vapors no longer affect building occupants. Remediation is the process of removing the source of contamination.
Point Blue, LLC, provides environmental consulting services to clients throughout the Midwest with team of experienced environmental professionals skilled in property transaction, due care, site investigations, site remediation, vapor intrusion, hydrogeological monitoring, and brownfield programs. Point Blue focuses on helping clients reduce their environmental risks while protecting our natural resources for a more sustainable future.