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Frequent Questions

What kind of results does RSEI provide?


RSEI provides a full risk-related perspective for air and water releases, and hazard-based and pounds-based perspectives releases to air, water, and land. The full risk-related perspective covers over 400 chemicals and chemical categories, and over 50,000 reporting facilities (over all 24 years). RSEI also contains important information databases (chemical, facility, census, etc.) that are fully accessible within and outside the model. RSEI has multi-faceted outputs including geographic information system (GIS) mapping, graphs, sorted lists, and tables, etc. These outputs are exportable to other software applications for additional customizing.

Why examine risk-related results?


Reducing risk is a goal of the US Environmental Protection Agency, states, communities, and the general public. Risk-related assessments aid in allocating resources for maximizing risk reduction. Pounds-based, hazard-based and risk-related perspectives give very different results. Using pounds of releases as a risk surrogate incorrectly assumes that all chemicals are equally toxic and that every person is equally exposed.

How does RSEI differ from a formal risk assessment?


Formal risk assessments are complicated and time consuming to perform, and often require detailed data which are not always available. They are often limited in scope and geographic area. The risk-related estimates produced by RSEI do consider the important factors of risk assessment, but do not address every potential factor. RSEI results are meaningful only in comparison to other RSEI results, and do not describe a specific level of risk.

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Has RSEI been peer-reviewed?


The original model was reviewed by outside risk assessment experts in 1991, and submitted for Agency review and public comment in 1992. RSEI has undergone three reviews by EPA's Science Advisory Board: the overall methodology was reviewed in 1997, and the toxicity weighting system was reviewed separately twice. In addition, states reviewed the model and submitted comments in 1999, and model versions underwent beta testing in 1999, 2001, and 2002.

What kinds of analyses has RSEI been used for?


Risk, compliance, and EJ analysis of Federal facilities reporting to TRI (June 1997). Industry sector- and facility-based targeting and strategic planning by several EPA offices. Outside analysts have investigated:

Examples of data analysis charts by Region 4 using RSEI are available.

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Who is using RSEI?


What is New in RSEI Version 2.3.2?


Each new version of RSEI incorporates the latest TRI data, as well as changes to the input data and the methodology used to process the data and present the results. The following changes were made in Version 2.3.2:

For more details, see What is New in RSEI Version 2.3.2?.

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What chemicals are included in the model?


The installation package for Version 2.3.2 of the model incorporates TRI chemicals for the years 1996 through 2011. Data for years 1988-1995 are available upon request. There are 611 discrete chemicals and chemical categories. The model includes toxicity data for 435 of these chemicals.

What data sources were used for the toxicity values in the RSEI model?


The following data sources were used, in order of preference:

What are the strengths and limitations of the RSEI model?


RSEI provides a sophisticated approach to incorporating a risk-related perspective when analyzing the impacts of chemical releases; however, as a screening-level tool, RSEI should be supplemented with additional analyses. For more information, see Strengths and Limitations of the RSEI Model.

Where can I find out more about the model?


The methodology underlying the Risk-Screening Environmental Indicators is described in detail in the Methodology Document (PDF) (89 pp, 381K, About PDF). The User's Manual (PDF) (172 pp, 1.8 MB, About PDF) describes the model more generally and provides instruction on using the model interface.

Has the Risk-Screening Environmental Indicators model ever been known by another name?


Yes, the original project name was 'TRI Relative Risk-Based Environmental Indicators'.

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