Vapor Intrusion Survey

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Ninety-six percent (96%) of survey respondents consider vapor intrusion a concern, with a majority of the respondents working on more than five sites. One-third (33%) of the respondents have a policy or guidance in place, and forty percent (40%) refer to the EPA's Office of Solid Wate and Emergency Response (OSWER) vapor intrusion guidance. All regulatory programs within each state seem to be affected by VI. Forty-two (42%) of the respondents allow for biodegradation at petroleum sites. Less than half of the states look at future use when assessing vapor intrusion.

Click on each question to view results.

12. At your agency, is the vapor intrusion pathway:
a. currently a concern and being actively addressed
b. currently a concern but not being addressed
c. not currently a concern, but perceived to become an issue in the future
d. not a concern to this agency
e. unknown

13. If the answer to question 12 above is 'a', please estimate the number of sites at which vapor intrusion is currently being investigated.

14-18. Does your agency have a procedure for evaluating the vapor intrusion pathway?

14. Codified into law by either legislative act or regulation.
15. Official agency policy/guidance formally adopted by your agency’s management.

16. Informal agency operating procedure.
17. Agency procedure currently in active development.
18. Defer to U.S. EPA guidance.

19-25. Please characterize your agency's procedures as indicated.

19. Allow modeling for screening sites and/or closing sites from this pathway?
20. Apply to chlorinated VOC sites?
21. Apply to non-UST petroleum hydrocarbon sites?
22. Apply to UST petroleum hydrocarbon sites?
23. Assume biodegradation or different subsurface-to-indoor air attenuation rates for petroleum

hydrocarbon sites vs. chlorinated VOC sites?

24. Apply if building is not currently on the site but is known to be under construction or planned?
25. Require evaluation for a hypothetical future building to fully close out the site?

26. Please list any policy statements, guidance, or regulatory documents that relate to the vapor intrusion pathway including any Internet links.

27. What programs are affected by vapor intrusion at your agency?(Check all that apply)


  • Brownfields

  • Dry cleaners


  • Formerly Used Defense Sites

  • State-lead cleanups

  • Other

  • 28. If you answered 'Other' to question 27, please explain.

    29-31. According to the U.S. EPA, vapor intrusion is evaluated for soil gas or groundwater contamination found within 100 feet horizontally or vertically of the building foundation. What distance does your agency use?

    29. Not specified by the agency’s procedure.
    30. What horizontal distance (feet) is used?
    31. What vertical distance (feet) is used?

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