The California Department of Toxics Substances Control and the State Water Resources Control Board are working on a guidance document for screening buildings for the presence in the structures of contaminated vapor intrusion from soil and groundwater.
Whereas in the past the regulatory focus has been on soil and groundwater directly under the buildings, the new, expanded focus will also take into account vapor intrusion from neighboring structures along with vapor intrusion from sewer lines and other preferential pathways lateral to the building at issue. Under the new guidelines, it will be presumed that 3% of measured soil vapor contamination is making its way into the building at issue.
Four public meetings will be held on the draft guidance on April 1 at Cal EPA hq in Sacramento; on April 9 by webcast; on April 14 at the San Diego RWQCB hearing room; and on April 16 at the Council Chambers in the City of Commerce. Written comments may be made until April 30.
Go to https://www.waterboards.ca.gov/water_issues/programs/site_cleanup_program/vapor_intrusion/ for information on the meetings, how to submit comments and for a copy of the Guidance.
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