Site Mitigation & Restoration Program

We protect and maintain California’s land and places
by setting strict standards for land restoration and cleanup

Human and Ecological Risk Office

CalTOX Download Instructions

Disclaimer: CalTOX fate and exposure models are for research use only.  CalTOX has not been fully tested for a broad range of site/facility applications AND not on all versions of Windows or Excel. There could be errors in the mathematical algorithms that we have not yet identified. Problems may occur in the execution of Excel macros and in the display and printing of the spreadsheet output.  The toxicity criteria and exposure factors used by CalTOX may differ from those currently recommended by HERO, and HERO does not recommend use of this model for evaluation of site or facility chemical migration or risk estimate. This program should be considered as a research tool, and not used for regulatory decision making.

CalTOX software developed in the early 1990s is provided below although it may not work with some more recent computers.  A newer version of CalTOX: Multimedia Fate and Exposure Model software has been developed by Dr. Thomas McKone (Retired) and Dr. Hyeong-Moo Shin at Lawrence Berkeley Laboratory/University of California. The newer version of CalTOX 4.0 (Beta) is now available in the “Models” section near the bottom of Dr. Shin’s home page at the University of Texas, Arlington.

To access CalTOX 4.0 go to: 

In addition to the CalTOX Model Template, the above page also provides a User’s Guide, Biotransfer Factors, Landscape Factors, Parameter values and Technical Reports. 

Although it may not run on the most recent computers, the original CalTOX is archived below:

CalTOX 2.3 is provided as a set of zipped files. After downloading and unzipping, click on CalTOX to run the program. UnZipping this archive puts the six required Microsoft Excel® files in a folder.  All six of the files need to be located in the same folder.  Note that the Datcal file contains a single Microsoft Excel® spreadsheet file with the default distributions for the more than 150 parameters required by CalTOX.

The CalTOX Model Description contains six Adobe PDF files that describe the mathematical structure of the model shown in the CalTOX.xls file in the CalTOX23.Zip file. Separate documents describing the first version (1.5) and second version (2.3) of the CalTOX model are available. These documents describe the derivation of equations in the model citing the relevant scientific literature. The description of version 1.5 is lengthy and broken into 4 separate documents. The 2.3 documentation describes only changes made to version 1.5 in one document and comments of reviewers in a second document. Click below to download these model descriptions:

CalTOX Parameter Documentation files are also provided as Zip Archives.  Once unzipped, the Adobe PDF files describe how information in the scientific literature was used to determine the default distributions shown in the DatCal.xls file. Parameters are divided into two groups: chemically related and landscape-related.

CalTOX User Guide with documentation and description of how to use CalTOX is available for download.  Reading this file requires Adobe Reader or Adobe Acrobat® from Adobe Systems Inc.

Once again, CalTOX fate and exposure models are for research use only.  HERO has not checked or confirmed the behavior or calculations of this new CalTOX model.  HERO does not guarantee or recommend using this CalTOX model.  The above link are provided since CalTOX program may be a research tool, but should not be used for regulatory decision making. 

Page Modified 3/18/2019