Welcome to the Department of Toxic Substances Control

Johnson & Ettinger Models

The United States Environmental Protection Agency (U.S. EPA) developed a model in 1998 which estimates human health risks from subsurface vapor intrusion into buildings. This model is based on the work of Johnson and Ettinger, and is revised periodically to incorporate different assumptions about soil properties as well as new human health criteria developed by U.S. EPA. The U.S. EPA model, fact sheet, and users Guide are distributed at: http://www.epa.gov/oswer/riskassessment/airmodel/johnson_ettinger.htm

The Human and Ecological Risk Division has taken this model and incorporated human health criteria specific to California, as developed by the Cal/EPA Office of Environmental Health Hazard Assessment (OEHHA). This will be periodically updated as new California criteria are released by OEHHA, however it is the responsibility of the user to verify that all criteria in these models are current.

You can download these Excel® files and insert data to calculate estimates for a specific site. Microsoft Excel® or the Microsoft Excel® Viewer are required to view these files. If you do not have Excel® loaded on your computer, you can download the free Excel® Viewer here.

Screening-Level Model for Groundwater Contamination
Screening-Level Model for Soil Gas Contamination

Final Guidance for the Evaluation & Mitigation of Subsurface Vapor Intrusion to Indoor Air
Technical Memorandum Superfund JE Model Spreadsheet Error
User's Guide for Evaluating Subsurface Vapor Intrusion into Buildings (Draft) (2.5 MB)
Fact Sheet - Correcting the Henry's Law Constant for Soil Temperature

Copyright © 2007 State of California