About Vapor Intrusion
What are Vapor-Forming Chemicals?
Vapor-forming chemicals can easily move into the air and form vapors. Common ones include solvents used in dry cleaning, degreasing, gasoline and diesel fuel. Examples of toxic vapor-forming chemicals are:
- Tetrachloroethylene, also called perchloroethylene (“perc” or PCE): PCE is known to the State of California to cause cancer. Many dry cleaners have used PCE for decades, but this use will be phased out by 2023.
- Trichloroethylene (TCE): TCE is known to the State of California to cause cancer and harm reproductive health. TCE is commonly used in industries to remove oil or grease. It’s also in some household products such as stain removers and adhesives.
- Naphthalene: Naphthalene is known to the State of California to cause cancer. Sources include inks, dyes, fossil fuels, mothballs, tar, tobacco smoke, and burning of wood.
What are other sources of vapor-forming chemicals?
Many consumer products, such as household cleaners, furniture, adhesives and paints, contain these chemicals and can pollute indoor air. Vapor-forming chemicals in outdoor air can also enter buildings.
Vapor Intrusion and Your Health Fact Sheet
The Vapor Intrusion and Your Health Fact Sheet is a general overview about vapor intrusion.
Vapor Intrusion Modules
February 2024 Supplemental Vapor Intrusion Guidance Presentation - YouTube
This presentation provides a general overview of vapor intrusion basics and the guidance document:
- vapor intrusion basics and implementation of the guidance
- revisions from the 2020 Draft Supplemental Vapor Intrusion Guidance
- each of the four steps in the screening and evaluation process
- Attachments 1 through 4, additional considerations for vapor intrusion evaluations, including lines of evidence, petroleum-specific considerations, sewers and other vapor conduits, and groundwater as a line of evidence.
May 2020 Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion Public Workshop
The videos in this playlist describe the new "Draft Supplemental Guidance: Screening and Evaluating Vapor Intrusion." The draft guidance is currently available for public comment. The first presentation is targeted to the general public, the remaining presentations give detailed information for technical audiences. The presentations provide information on the process, vapor intrusion background, a summary of the guidance, information about updates to the GeoTracker database, and a case study.
State Water Board YouTube Website: https://www.youtube.com/playlist?list=PLb4ywLqRQSopT0TzQBvxC9VAsUrdWQ9on
Tutorial Video on Uploading Vapor Data Into GeoTracker
This video is a tutorial on how to navigate and input vapor intrusion related information into GeoTracker Electronic Submittal of Information Portal. The video provides background on the vapor intrusion database, how to upload field point data and create building profiles, as well as how to navigate in the portal to upload tools related to vapor intrusion information.
State Water Board YouTube Website: https://www.youtube.com/watch?v=5X6pfZHMypA&t=532s
Other Vapor Intrusion Resources
Vapor Intrusion Webpage Links:
- DTSC Site Mitigation and Restoration Program Vapor Intrusion
- DTSC Human Health Risk (HERO)
- USEPA Vapor Intrusion
- ITRC – Vapor Intrusion Documents
Existing Vapor Intrusion Guidance Document Links:
- 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)
*Please note this is not the complete list of existing vapor intrusion guidance documents.
Stay informed
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Contact Us
- Email: DWQ-vaporintrusion@waterboards.ca.gov
- Questions about the proposed amendment to State Water Board Resolution 92-49:
Roshani Dantas
Email: Roshani.Dantas@waterboards.ca.gov
Phone: (916) 327-8542