Risk-Screening Environmental Indicators (RSEI) Model Reference Document History

The documents on this page describe the evolution of EPA's Risk-Screening Environmental Indicators (RSEI) model over the past 20 years. The reports listed below were released to document various aspects and iterations 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 March 2024 methodology document for Version 2.3.12.

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

• Reports
• Methodology documents
• Microdata guidance
• Data dictionary
• 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 Science Advisory Board (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 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 instead of a weighted binning approach. 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 EPA's Office of Pollution Prevention and Toxics (OPPT) "ground-truthing" analysis which compares results of the air model component of the 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 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 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 internal reviews, comments, and recommendations received by EPA's SAB, public and peer review, and other stakeholders. 

1. Risk-Screening Environmental Indicators (RSEI) Methodology Version 2.3.11 (pdf) (2.01 MB, March 2023) This methodology document accompanies version 2.3.11 of the Risk-Screening Environmental Indicators model.
2. Technical Appendices for Version 2.3.11, March 2023.
   These documents support the Methodology Document for RSEI Version 2.3.11, and provide additional information on the data used in the model:  Technical Appendix A - Toxicity Weights for TRI Chemicals and Chemical Categories, v2.3.11 (pdf) (238.24 KB, March 2023)   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories, v2.3.11 (pdf) (335.57 KB, March 2023) Technical Appendix C - Derivation of Model Exposure Parameters v2.3.11 (pdf) (279.75 KB, March 2023) Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities, v2.3.11 (pdf) (180.14 KB, April 2023) Technical Appendix E - Derivation of Stack Parameter Data, v2.3.11 (pdf) (217.52 KB, April 2023) Technical Appendix F - Summary of Differences between RSEI Data and the TRI National Analysis, v2.3.11 (pdf) (140.74 KB, April 2023)
3. Risk-Screening Environmental Indicators (RSEI) Methodology Version 2.3.10 (pdf) (1.17 MB, May 2022)
   This methodology document accompanies version 2.3.10 of the Risk-Screening Environmental Indicators model.
4. Technical Appendices for Version 2.3.10, March 2022.
   These documents support the Methodology Document for RSEI Version 2.3.10, and provide additional information on the data used in the model:
   Technical Appendix A - Toxicity Weights for TRI Chemicals and Chemical Categories, v2.3.10 (pdf) (231.24 KB, March 2022)
   Technical Appendix B - Physicochemical Properties for TRI Chemicals and Chemical Categories, v2.3.10 (pdf) (324.76 KB, March 2022)
   Technical Appendix C - Derivation of Model Exposure Parameters, v2.3.10 (pdf) (278.01 KB, March 2022)
   Technical Appendix D - Locational Data for TRI Reporting Facilities and Off-site Facilities, v2.3.10 (pdf) (623.83 KB, March 2022)
   Technical Appendix E - Derivation of Stack Parameter Data, v2.3.10 (pdf) (659.75 KB, March 2022) Technical Appendix F - Summary of Differences between RSEI Data and the TRI National Analysis, v2.3.10 (pdf) (134.6 KB, March 2022)
5. Methodology Document for RSEI Model Version 2.3.9, December 2020.
   This methodology document accompanies version 2.3.9 of the Risk-Screening Environmental Indicators model.
6. Technical Appendices for Version 2.3.9, December 2020.
   These documents support the Methodology Document for RSEI Version 2.3.9, 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
7. Methodology Document for RSEI Model Version 2.3.8, December 2019.
   This methodology document accompanies version 2.3.8 of the Risk-Screening Environmental Indicators model.
8. Technical Appendices for Version 2.3.8, December 2019.
   These documents support the Methodology Document for RSEI Version 2.3.8, 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 2.3.7, December 2018.
   This methodology document accompanies version 2.3.7 of the Risk-Screening Environmental Indicators model.
10. Technical Appendices for Version 2.3.7, December 2018.
    These documents support the Methodology Document for RSEI Version 2.3.7, 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
11. Methodology Document for RSEI Model Version 2.3.6, December 2017.
    This methodology document accompanies version 2.3.6 of the Risk-Screening Environmental Indicators model.
12. Technical Appendices for Version 2.3.6, December 2017.
    These documents support the Methodology Document for RSEI Version 2.3.6, 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
13. Methodology Document for RSEI Model Version 2.3.5, January 2017.
    This methodology document accompanies version 2.3.5 of the Risk-Screening Environmental Indicators model.
14. Technical Appendices for Version 2.3.5, January 2017.
    These documents support the Methodology Document for RSEI Version 2.3.5, 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
15. 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.
16. 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
17. 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. 
18. 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
19. 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. 
20. 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
21. 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.
22. 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
23. User's Manual for RSEI Model Version 2.3.2, July 2013.
24. 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.
25. 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
26. Methodology Document for RSEI Model Version 2.1, January 2004.
    This methodology document accompanies version 2.1 of the Risk-Screening Environmental Indicators model.
27. 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
28. 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 methodology, the toxicity weighting, the chronic ecological indicator and other issues. OPPT's responses and proposed changes are also discussed.
29. 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.

Microdata Guidance

1. Documentation for Risk-Screening Environmental Indicators (RSEI) Geographic Microdata (RSEI-GM) for Version 2.3.5
   This microdata methodology document accompanies version 2.3.5 of the Risk-Screening Environmental Indicators model.

Data Dictionary

1. Risk-Screening Environmental Indicators (RSEI) Data Dictionary for Version 2.3.6
   This data dictionary accompanies version 2.3.6 of the Risk-Screening Environmental Indicators model.

2. Risk-Screening Environmental Indicators (RSEI) Data Dictionary for Version 2.3.5
   This data dictionary accompanies version 2.3.5 of the Risk-Screening Environmental Indicators model.

User's manual

1. User's Manual for RSEI Model Version 2.1.5, September 2007
2. User's Manual for RSEI Model Version 2.1.2, August 2004
3. RSEI Version 2.1 Distribution Package
   Information distributed to users in technical release of RSEI Version 2.1
4. User's Manual for RSEI Model Version 2.1, December 2002
   This manual accompanies version 2.1 of the Risk-Screening Environmental Indicators model.
5. 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.