Identifying and Mitigating Vapor Intrusion Risks for Building Occupants

Vapor intrusion occurs when vapor-forming chemicals migrate from a subsurface source into an overlying building. The subsurface source is typically contaminated soil and/or groundwater. These vapor-forming chemicals can cause indoor air quality (IAQ) problems and sometimes pose a health concern for building occupants.

Examples of vapor-forming chemicals listed by the U.S. Environmental Protection Agency (EPA) include:

• Volatile organic compounds (VOCs), such as trichloroethylene and benzene

• Select semi-volatile organic compounds (SVOCs), such as naphthalene

The agency goes on to warn that in extreme cases, the vapors may accumulate in dwellings or occupied buildings to levels that may pose:

• Near-term safety hazards (e.g., explosion)

• Acute health effects

“Vapor intrusion of soil vapors, from naturally occurring methane to synthetic chemicals into the built environment, is a concern to occupant health. These unwanted compounds can result in acute occupant exposure to high concentrations over short periods and/or chronic exposure to low concentrations over extended periods. Both acute and chronic chemical exposure may pose an unacceptable risk of health effects,” said Jeff Bannon, PG, Vice President of Environmental Services for Clark Seif Clark (CSC). “Creating a sampling plan, executing that plan, interpreting the results, and assessing occupant risk over both the short and long-term requires consideration of numerous factors. Consideration is given to chemicals used and stored in the structure, building activities, type and concentration of compounds in soil beneath the structure, ventilation, building pressures, and much more. At CSC, our expert staff can identify vapor intrusion risks utilizing the most advanced testing methods, monitoring instruments, and decades of experience. If vapor intrusion issues are found, there are mitigation techniques that can be implemented to improve indoor conditions.”

CSC recently sponsored an educational video about vapor intrusion and IAQ that can be seen at: https://youtu.be/kkxtq1TfbnQ.

To learn more about this or other environmental, industrial hygiene, indoor environmental quality, health, and safety services, please visit www.csceng.com, email csc@csceng.com, or call (800) 807-1118.

About Clark Seif Clark

CSC was established in 1989 to help clients in both public and private sectors address indoor air quality, occupational, and environmental, health, and safety (EH&S) issues. CSC is a leading provider of these services with multiple offices along the western seaboard and southwest. The company believes in science-based protocols and has a strong background in engineering, making them the preferred environmental consultants to industrial clients, healthcare facilities, architects, schools, builders, contractors, developers, and real estate professionals.

Contact Information

Paul Cochrane

President

Cochrane & Associates, LLC

Contact via E-mail