Environmental Screening Levels
Environmental Screening Levels
The Environmental Screening Levels (ESLs) provide conservative screening levels for over 100 chemicals found at sites with contaminated soil and groundwater. They are intended to help expedite the identification and evaluation of potential environmental concerns at contaminated sites. ESLs address a range of media (soil, groundwater, soil gas, and indoor air) and a range of concerns (e.g., impacts to drinking water, vapor intrusion, and impacts to aquatic life). These ESL documents are prepared by staff of the San Francisco Bay Regional Water Quality Board (Water Board). Information provided in the document is not intended to establish policy or regulation. Also note that, in general, ESLs are not used at sites that are subject to the Low-Threat Underground Storage Tank Closure Policy.
Contents and Update Process
Environmental Screening Levels (ESLs) Content
- Cover Memo (Feb. 2016) Includes discussion of notable changes in latest update
- User's Guide (Feb. 2016) Derivation and Application of ESLs.
- ESL Workbook (Feb. 2016, Rev 3) The ESL Workbook (Microsoft Excel 2010) includes four parts: Summary Tables, Interactive Tool, Calculations Tables, and Input Parameters Tables. See the User's Guide for more information about how to use the ESL Workbook.
- ESL Summary Tables (Feb. 2016, Rev 3) Includes PDF version of the Groundwater, Soil, and Vapor (Subslab/Soil Gas and Indoor Air) ESL Summary Tables from the ESL Workbook file.
- Frequently Asked Questions (Feb. 2016) Answers to some of the most common questions we receive.
Major updates and minor revisions to the ESLs will be posted to this website when needed. The current major update (e.g., Feb 2016) and minor revision (e.g., Rev #) version is listed on the top of the Table Index and in the footer of each sheet within the ESL Workbook. The following link (ESL Status Sheet) provides the current revision number and lists the most recent changes for that revision.
Electronic Mailing List for Updates
When ESLs are updated or revised, we send an email notification to those are on the ESL mailing list. You can join the ESL mailing list by clicking the link below. Once there, check the ESL box under the General category.
Vapor Intrusion Updates
The State Water Resources Control Board, the San Francisco Bay Regional Water Quality Control Board, and the Department of Toxic Substances Control (DTSC), are currently developing a supplemental vapor intrusion guidance document for conducting uniform vapor intrusion evaluations in California. This guidance document will serve as a 2018 Supplement to existing guidance documents. This guidance will provide information on the following topics:
- Soil gas, subslab, indoor air, and outdoor air sampling recommendations that are focused on understanding spatial and temporal variability
- Sewers as a potential migration route and pathway of exposure
- Recommendations for use of USEPA 2015 attenuation factors to screen buildings
- Risk management framework for vapor intrusion
- California-specific vapor intrusion database
The Supplemental VI guidance is anticipated for release to the public in mid-2018. Following release, DTSC and the Water Boards will hold public workshops likely in Northern and Southern California. Actual dates will follow once the document is completed. Click here to view a presentation with updates on the supplemental vapor intrusion guidance document prepared for the November 2017 Groundwater Resources Association Dry Cleaner Conference.
- Draft Interim Framework for Assessment of Vapor Intrusion at TCE-Contaminated Sites in the San Francisco Bay Region (TCE VI Framework) (2014)
- Supplemental Instructions to State Water Board December 8, 1995, Interim Guidance on Required Cleanup at Low Risk Fuel Sites (1996)
- Nicole Fry
SF Bay Regional Water Quality Control Board
1515 Clay Street, Suite 1400
Oakland, CA 94612