Recent Updates to State-Level Regulations

Guidelines for vapor intrusion assessment are presented in documents issued on local, state, and federal levels. In recent years, there have been a number of key updates to vapor intrusion guidance documents on the state level. For example, the California Environmental Protection Agency Vapor Intrusion Working Group (composed of several local and state environmental regulatory agencies) released California’s long-anticipated draft supplement vapor intrusion guidance in February 2020. This guidance includes information on a variety of vapor intrusion topics, including recommendations for soil gas, sub-slab, indoor air, and outdoor air sampling, as well as use of vapor intrusion attenuation factors. The document is currently being revised based on responses received during the public comment period, which ended in June 2020. A final version of this guidance is anticipated for release in Spring 2021. Other states are also in the process of updating their vapor intrusion guidance documents. Specifically, Washington’s Department of Ecology is currently drafting an update to their 2009 guidance for evaluating soil vapor intrusion. An updated draft is anticipated to be issued for public comment in 2021.

For more information on how this may impact your projects, please contact your Langan Project Manager or:

Elizabeth Kimbrel
Senior Project Manager
ekimbrel@langan.com 
206.504.3489