The documents on this page describe the evolution of Risk Screening Environmental Indicators model over the past 20 years. The reports listed below were released to document various aspects of the model. The methodology documents describe the data and methods used to calculate RSEI results, and the user's manuals describe how to use the model interface. All of the documents refer to the RSEI model as implemented at the time, and may not reflect the current version.

Get RSEI's most recent January 2017 methodology document for Version 2.3.5.

On this page: Note that some documents refer to the "TRI Relative Risk-Based Environmental Indicators," the original project name.

• Reports
• Methodology documents
• User's manuals

Reports

1. Toxics Release Inventory Relative Risk-Based Environmental Indicators: Interim Toxicity Weighting Summary Document, June 1997
   This report, prepared for the June 1997 SAB review, discusses the methods used to derive toxicity weights from published toxicity values and from dose-response data found in the literature. In response to comments received from the SAB, changes were made to the toxicity weighting methodology used in the Indicators model. Data from the Office of Pesticide Programs was approved for inclusion and the algorithms used to assign toxicity weights have been modified to proportionally reflect the toxicity values themselves. However, the basic philosophy supporting the methodology has not changed.
2. Ground-Truthing of the Air Pathway Component of OPPT's Risk-Screening Environmental Indicators Model, October 1998
   This draft report describes OPPT's "ground-truthing" analysis which compares results of the air model component of the Indicators model to results obtained from a state air dispersion model used for regulatory purposes. The comparison evaluated the impact of using a combination of median data and generic assumptions in the Indicators model as opposed to using more site-specific data.
3. Estimates of Stack Heights and Exit Gas Velocities for TRI Facilities in OPPT's Risk-Screening Environmental Indicators Model, June 1999
   This report describes the Agency's improvements to the accuracy of the Indicators model through incorporation of facility-specific stack heights and exit gas velocities where available, or through estimation of stack heights and exit gas velocities by facilities' Standard Industrial Classification (SIC) codes.

Methodology documents

The RSEI model has undergone a series of changes due to the Agency's responses to reviews and comments by EPA's Science Advisory Board (SAB) and testers.

1. Toxics Release Inventory Relative Risk-Based Environmental Indicators: Summary of Comments Received on the Draft 1992 Methodology and Responses to Comments, May 1997
   This document contains general comments on the original Indicators methodology, the toxicity weighting, the chronic ecological indicator and other issues. OPPT's responses and proposed changes are also discussed.
2. Toxics Release Inventory Relative Risk-Based Environmental Indicators Methodology, June 1997
   This report, prepared for the June 1997 SAB review, explains how the proposed Indicators are constructed, and includes discussions of the conceptual methodology, data sources, and the computational approach.
3. Methodology Document for RSEI Model Version 2.1, January 2004
   This methodology document accompanies version 2.1 of the Risk-Screening Environmental Indicators model.
4. Methodology Document for RSEI Model Version 2.1.2, August 2004
   This methodology document accompanies version 2.1.2 of the Risk-Screening Environmental Indicators model.
5. Methodology Document for RSEI Model Version 2.1.5, October 2007
   This methodology document accompanies version 2.1.5 of the Risk-Screening Environmental Indicators model.
6. Methodology Document for RSEI Model Version 2.3.2, July 2013
   This methodology document accompanies version 2.3.2 of the Risk-Screening Environmental Indicators model. 
7. Methodology Document for RSEI Model Version 2.3.3, July 2015
   This methodology document accompanies version 2.3.3 of the Risk-Screening Environmental Indicators model. 
8. Technical Appendices for Version 2.3.3, July 2015
   These documents support the Methodology Document for RSEI Version 2.3.3, and provide additional information on the data used in the model:
   Technical Appendix A - Toxicity Weights for TRI Chemicals and Chemical Categories
   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
   Technical Appendix C - Derivation of Model Exposure Parameters
   Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
   Technical Appendix E - Derivation of Stack Parameter Data
   Technical Appendix F - Summary of Differences Between RSEI Data and the TRI Public Data Release
9. Methodology Document for RSEI Model Version 2.3.4, December 2015
   This methodology document accompanies version 2.3.4 of the Risk-Screening Environmental Indicators model.
10. Technical Appendices for Version 2.3.4, December 2015
    These documents support the Methodology Document for RSEI Version 2.3.4, and provide additional information on the data used in the model:
    Technical Appendix A - Toxicity Weights for TRI Chemicals and Chemical Categories
    Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
    Technical Appendix C - Derivation of Model Exposure Parameters
    Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
    Technical Appendix E - Derivation of Stack Parameter Data
    Technical Appendix F - Summary of Differences Between RSEI Data and the TRI Public Data Release

User's manual

1. User's Manual for OPPT's Risk-Screening Environmental Indicators Model: Version 1.0, November 1999
   This manual describes the Indicator methodology, operations of the computer model and the step-by-step processes to perform them, and pre-run queries available with the model.
2. User's Manual for RSEI Model Version 2.1, December 2002
   This manual accompanies version 2.1 of the Risk-Screening Environmental Indicators model.
3. Technical Appendices for Version 2.1, December 2002
   These documents support the User's Manual and the Methodology Document for RSEI Version 2.1, and provide additional information on the data used in the model:
   Technical Appendix A - Listing of All Toxicity Weights for TRI Chemicals and Chemical Categories
   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
   Technical Appendix C - Derivation of Model Exposure Parameters
   Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
   Technical Appendix E - Derivation of Stack Parameter Data
   Technical Appendix F - Summary of Differences Between RSEI Data and TRI Public Data Release
4. RSEI Version 2.1 Distribution Package
   Information distributed to users in technical release of RSEI Version 2.1
5. User's Manual for RSEI Model Version 2.1.2, August 2004
6. Technical Appendices for Version 2.1.2, August 2004
   These documents support the User's Manual and the Methodology Document for RSEI Version 2.1.2, and provide additional information on the data used in the model:
   Technical Appendix A - Listing of All Toxicity Weights for TRI Chemicals and Chemical Categories
   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
   Technical Appendix C - Derivation of Model Exposure Parameters
   Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
   Technical Appendix E - Derivation of Stack Parameter Data
   Technical Appendix F - Summary of Differences Between RSEI Data and TRI Public Data Release
7. User's Manual for RSEI Model Version 2.1.5, September 2007
8. Technical Appendices for Version 2.1.5, September 2007
   These documents support the User's Manual and the Methodology Document for RSEI Version 2.1.5, and provide additional information on the data used in the model:
   Technical Appendix A - Listing of All Toxicity Weights for TRI Chemicals and Chemical Categories
   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
   Technical Appendix C - Derivation of Model Exposure Parameters
   Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
   Technical Appendix E - Derivation of Stack Parameter Data
   Technical Appendix F - Summary of Differences Between RSEI Data and TRI Public Data Release
9. User's Manual for RSEI Model Version 2.3.2, July 2013
10. Technical Appendices for Version 2.3.2, July 2013
    These documents support the User's Manual and the Methodology Document for RSEI Version 2.3.2, and provide additional information on the data used in the model:
    Technical Appendix A - Toxicity Weights for TRI Chemicals and Chemical Categories
    Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories
    Technical Appendix C - Derivation of Model Exposure Parameters
    Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities
    Technical Appendix E - Derivation of Stack Parameter Data
    Technical Appendix F - Summary of Differences Between RSEI Data and the TRI Public Data Release
     

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