Vapor Intrusion


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.

Vapor Intrusion Information

Feb 2020 Draft Supplemental Guidance

February 2020 Draft Supplemental Guidance

The Public 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 for available public meetings.

Executive Summary Fact Sheet

Executive Summary Fact Sheet

The Executive Summary Fact Sheet highlights the topics suggested and briefly describes the four recommended steps for screening and evaluating vapor intrusion.

Hard Copy Locations

***Due to the COVID-19 public health emergency, access to hard copies are currently not available.

CalEPA Building
1001 I Street, Sacramento, CA
Contact Abe Waggoner, (916) 341-5895

North Coast Regional Water Board Office
5550 Skylane Building, Suite A, Santa Rosa, CA
Contact: Paul Nelson, (707) 576-2686

Central Valley Regional Water Board Office
1685 E. Street, Fresno, CA
Contact: Christine Hernandez, (559) 445-6542

San Francisco Bay Regional Water Board Office
1515 Clay Street, #1400, Oakland, CA
Contact: Melinda Wong, (510) 622-2430

Lahontan Regional Water Board Office (South Lake Tahoe)
2501 Lake Tahoe Blvd., South Lake Tahoe, CA
Contact: Jeff Brooks, (530) 542-5420

Lahontan Regional Water Board Office (Victorville)
15095 Amargosa Road, Bldg. 2, Suite 210, Victorville, CA
Contact: Alonzo Poach, (760) 241-7365

Los Angeles Regional Water Board Office
320 W. 4th Street, Suite 200, Los Angeles, CA
Contact: Lucinda (Cindy) Flores, (213) 576-6633

Santa Ana Regional Water Board Office
3737 Main Street, Suite 500, Riverside, CA
Contact: Lenore Gamez, (951) 782-4905

San Diego Regional Water Board Office
2375 Northside Drive, Suite 100, San Diego, CA
Contact: Records Request Hotline, (619) 516-1990

Department of Toxic Substances Control Regional Office
5796 Corporate Avenue, Cypress, CA
Contact: Jone Barrio, (714) 484-5336

Department of Toxic Substances Control Regional Office
9211 Oakdale Avenue, Chatsworth, CA
Contact: Robert Hardison, (818) 717-6521

May 2020 Agenda

The CalEPA Vapor Intrusion Workgroup has developed and posted video presentations online and will host two live Question and Answer Sessions in lieu of the public meetings.

April 2020 Agenda

Due to the COVID-19 public health emergency, the original public information meetings scheduled for April 2020 are postponed until further notice.

Public Comment due 12:00 noon, June 1, 2020

Written comments on February 2020 Public Draft Supplemental Guidance must be submitted by 12:00 noon, June 1, 2020 by mail or email.

Methods to Submit Comments

See Comment Submission Instructions for details.

To help the CAlEPA Vapor Intrusion Workgroup to organize comments, please use one of the designated comment forms and electronically submit your comments to the email provided below. The work group offers Comment Form A (Adobe® Version) and Comment Form B (Microsoft® Word Version). Alternatively, you may also submit your comments in a letter (or email) drafted in the official format of your agency or company, or in a format of your choosing.

Below are the available methods (use one):

How to Submit Comments:

  1. Email:
    (please add “Comment Submittal” to subject line)
  2. Mail: State Water Resources Control Board, Division of Water Quality
    CalEPA VI Workgroup, Attention: Abe Waggoner
    1001 I Street, 15th Floor, Sacramento, CA 95814


Please refer to Comment Submission Instructions or contact Abe Waggoner at or (916) 341-5895.

Note on Response to Comment

Please Note: The Vapor Intrusion Work Group will group and categorize comments and prepare responses. Responses to individual comments will not be provided.

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

Guidance on Uploading Vapor Data into GeoTracker

The Vapor Intrusion and Your Health Fact Sheet is a general overview about vapor intrusion.

California Vapor Intrusion GeoTracker Database

Vapor Intrusion is a complex, highly variable science. A robust empirical dataset is needed to help us better understand vapor behavior.

GeoTracker Database

Guidance on Uploading Vapor Data into GeoTracker

Guidance on Uploading Vapor Data into GeoTracker

This document provides instruction on how to input relevant vapor intrusion information used in a vapor intrusion assessment into the GeoTracker database.

ESI Login

ESI Information Page

GeoTracker Help Desk

State Water Resources Control Board

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  • New! General Overview and Technical Series Video Presentations
  • New! Live Question and Answer Sessions
    • May 14, 2020
      • Technical Session 1:30-3:30 pm
      • General Overview 6:00-8:00 pm
    • May 19, 2020
      • Technical Session 1:30-3:30 pm
      • General Overview 6:00-8:00 pm

* Please see Public Notice May 2020 for more details


If you have any questions about vapor intrusion, please email us at:

Or contact:
State Water Board

Tina Ures
Engineering Geologist
Phone: (916) 341-5749