Toxic vapors in indoor air can come from multiple sources – underground contamination, consumer products or outdoor air. Vapors can travel between soil particles and reach ground surface.
The Department of Toxic Substances Control (DTSC), the State Water Board, and the San Francisco Bay Regional Water Quality Control Board (SF Bay Regional Water Board) are currently developing a supplemental vapor intrusion guidance document for conducting uniform vapor intrusion evaluations in California. This guidance document, when finalized, will serve as a supplement to existing guidance (see below). The new guidance will provide detailed 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 attenuation factors
- Risk management framework for vapor intrusion
- California-specific vapor intrusion database
Existing Guidance Documents:
- OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air (2015)
- Advisory – Active Soil Gas Investigations (July 2015)
- Interim Framework for Assessment of Vapor Intrusion at TCE-Contaminated Sites in the San Francisco Bay Region (2014)
- Final Guidance for the Evaluation & Mitigation of Subsurface Vapor Intrusion to Indoor Air (2011)
*This is not the complete list of existing vapor intrusion guidance documents.
This document provides instruction on how to input relevant vapor intrusion information used in a vapor intrusion assessment into the GeoTracker database.
What is Vapor Intrusion?
When some chemicals are spilled or dumped, they can form vapors that travel through the soil, reach under buildings, and contaminate the indoor air. Vapors can reach the indoor air through cracks in foundations, utility pipes, and sewer lines.
What is Trichloroethylene?
Trichloroethylene is commonly used in industries to remove oil or grease. It’s also in some household products such as stain removers and adhesives.
Where Can I Find More Vapor Intrusion Information?
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- Coming Soon - Public Notice 2019 Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion
- Coming Soon – Public Workshop Dates and Locations
- Coming Soon – 2019 Public Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion
- Coming Soon – Executive Summary Draft 2019 Supplemental Guidance Fact Sheet
- Coming Soon - Vapor Intrusion and Your Health Fact Sheet
- Coming Soon - Trichloroethylene (TCE) in Indoor Air Fact Sheet