Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion
The Department of Toxic Substances Control (DTSC), State Water Resources Control Board, and San Francisco Bay Regional Water Quality Control Board have developed supplemental vapor intrusion guidance for conducting vapor intrusion evaluations in California.
The Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion is available for review and public comment until 12:00 noon, April 30, 2020. See Public Notice (below) for available public meetings.
The Draft Supplemental Guidance provides information on the following topics:
- Soil gas, subslab, indoor air, and outdoor air sampling recommendations that are focused on understanding spatial and temporal variability
- Recommendations for use of USEPA 2015 vapor intrusion attenuation factors
- Risk management framework for vapor intrusion
- California-specific vapor intrusion database in Geotracker
New! February 2020 – Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion
New! Executive Summary Fact Sheet: English / Spanish
New! Public Notice – February 2020 Draft Supplemental Guidance: English / Spanish
Public Information Meetings and Webinar Locations (details in Public Notice)
April 1, 2020 – 1:00PM and 6:00PM
CalEPA Headquarters – Sierra Hearing Room
1001 I Street, Sacramento, CA 95814
This meeting will also be webcast from CalEPA’s Live Webcasts page
April 9, 2020 – 1:00PM and 6:00PM
Online Webinar
Call-In Number: (916) 562-0861; participant passcode: 779621632
April 14, 2020 – 1:00PM and 6:00PM
San Diego Regional Water Quality Control Board, Hearing Room 2375
Northside Drive, Suite 100, San Diego, CA 92108
April 16, 2020 – 1:00PM and 6:00PM
City of Commerce Council Chambers
2535 Commerce Way, Commerce, CA 90040
Public Comments
Comments on the Draft Guidance may be submitted electronically or by mail using one of the Comment Forms provided or by letter. Please see Instructions for information.
Instructions: English / Spanish
Comment Form A (Adobe®): English / Spanish
Comment Form B (Microsoft® Word): English / Spanish
Mail to:
State Water Resources Control Board, Division of Water Quality,
CalEPA VI Workgroup, Attention: Abe Waggoner,
1001 I Street, 15th Floor, Sacramento, CA 95814
OR
Email to: DWQ-vaporintrusion@waterboards.ca.gov
Vapor Intrusion Fact Sheet
New! Vapor Intrusion and Your Health Fact Sheet (general overview of vapor intrusion): English / Spanish
Vapor Intrusion E-List
Subscribers will receive e-mail notifications regarding news on topics relevant to vapor intrusion—the migration of volatile contaminants through soil and into buildings and potentially causing unacceptable chemical exposure for building occupants. Topics include subsurface investigations and evaluation of potential exposure and human health risk from vapor intrusion.
Vapor Intrusion Guidance Documents
- Flow Diagram of DTSC Documents
- Advisory – Active Soil Gas Investigations (July 2015)
- Frequently Asked Questions (FAQ’s) (August 2015)
- Summary of Advisory Changes (2015)
- Final Guidance for the Evaluation & Mitigation of Subsurface Vapor Intrusion to Indoor Air (October 2011; also known as the Vapor Intrusion Guidance)
DTSC’s Vapor Intrusion Guidance provides a stepwise and sometimes iterative process for the investigation of vapor intrusion and describes procedures for screening and site-specific evaluation of potential risks associated with this exposure pathway. The DTSC Screening-Level Model spreadsheets that used the Johnson & Ettinger (J&E) model to predict theoretical indoor air concentrations of contaminants from soil gas and groundwater data have been removed because they were not updated and are not based on the most current J&E model spreadsheet tool from USEPA. - Summary of Changes Between Interim Final and Final Guidance
- Human Health Risk
- Archived Screening-Level Model for Soil Gas Contamination
- Archived Screening-Level Model for Groundwater Contamination
- Vapor Intrusion Public Participation Advisory (March 2012)
DTSC developed this Advisory to help determine and implement appropriate public participation coordination and activities at sites where a potential vapor intrusion risk has been identified. The Advisory is a companion document to DTSC’s Vapor Intrusion Guidance and Vapor Intrusion Mitigation Advisory. In addition, the Advisory supplements DTSC’s Public Participation and Procedures Manual. - Vapor Intrusion: Decision Framework for Testing Indoor Air & Overview of Sampling Procedures Presented at the February 2012 CUPA Conference
- Vapor Intrusion Mitigation Advisory, Revision 1 (October 2011)
Provides a framework that guides the reader through the decision process for 1) determining if mitigation is appropriate for the project site, 2) selecting a mitigation system that is protective of human health, and 3) ensuring that implementation is sustainable for the duration of mitigation. Emphasizes public participation and implementation considerations. Identifies likely technologies for vapor intrusion mitigation, but does not identify proven technologies. - Summary of Changes Reflected in Revision 1