Vapor Intrusion

The State Water Resources Control Board (State Water Board) proposes to amend State Water Board Resolution No. 92-49 to include requirements for the investigation and assessment of vapor intrusion from vapor- forming chemicals. Vapor intrusion is a frequent problem at contaminated sites statewide. If left uncontrolled, chemical vapors can pose a significant health risk to communities living on and near contaminated sites. Vapor migration from the subsurface into buildings is complex which can cause an underestimation of vapor concentrations indoors. To control or prevent vapor migration into existing buildings or for future development, sites must first be assessed or screened for vapor intrusion risk.

Currently, vapor intrusion assessments are conducted on a case-by-case basis, using applicable guidance as appropriate. The proposed amendment to State Water Board Resolution No. 92-49 would establish state policy for water quality control that requires the use of an expeditious, consistent, and protective approach using statewide data for assessing vapor intrusion risk.

Public Notice
The State Water Board, Division of Water Quality, Site Cleanup Unit staff will hold two separate virtual public scoping meetings with the same presentation for a proposed amendment to State Water Board Resolution No. 92-49 (as amended on April 21, 1994, and October 2, 1996) to include requirements for the investigation and assessment of vapor intrusion at cleanup sites statewide. The meetings will provide an overview of the proposed elements of the draft amendment and an opportunity for the public to provide oral and written comments to be considered for inclusion into the draft resolution presented to the State Water Board Members for adoption at a later time and for the development of a Substitute Environmental Document.  A formal public comment period and public hearing will also be held before the State Water Board Members regarding the draft amendment at a later date.

• Public Notice (April 2022)
• Aviso Público (Abril 2022)

Public Comments
The CEQA scoping meeting will be conducted virtually, using online video and audio broadcast software. The State Water Board will accept both written and oral comments. Agencies, organizations, and the public will be able to provide oral comments directly through the online zoom meeting or zoom telephone access number. Please register in advance to access the zoom meeting online or by telephone.

Written comments must be received by 12:00 p.m. PDT (noon) on May 9, 2022.

How to Submit Written Comments:

1. Mail:
   Jeanine Townsend, Clerk to the Board
   State Water Resources Control Board
   P.O. Box 100, Sacramento, CA 95812-2000 (mail)
   1001 I Street, 15th floor, Sacramento, CA 95814 (hand-delivered)

   Couriers delivering hand copies of comment letters must check in with lobby security personnel, who can contact Jeanine Townsend at (916) 341-5620.

2. Email: (if less than 15 megabytes in total size)
   commentletters@waterboards.ca.gov
   (Please include the subject “Comment Letter – Resolution 92-49 Amendment Scoping”)

Future Notices
Any change in the date, time, and place of the scoping meetings will be publicly noticed on the State Water Board website and through Lyris e-mail list. Any person desiring to receive future notices concerning the proposed vapor intrusion amendment should sign up on the Lyris e-mail list. To sign up for a Lyris list, access the email List Subscription Form at: https://www.waterboards.ca.gov/resources/email_subscriptions/swrcb_subscribe.html, click the “Water Quality” tab, and check the box for “Vapor Intrusion.”