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Basic Information

The Risk-Screening Environmental Indicators (RSEI) model is a computer-based screening tool developed by EPA that analyzes factors that may result in chronic human health risks. These factors include the amount of toxic chemical releases, the degree of toxicity, and the size of the exposed population. RSEI analyzes these factors and calculates a numeric score. To give the score meaning, it must be ranked against other scores also produced by RSEI. The model highlights releases that pose the highest potential risk or potentially pose the highest risk. This way, RSEI helps policy makers and communities quickly identify situations that require further evaluation and set priorities for action.

What Is RSEI?

Fast and effective screening tool

RSEI uses information from the Toxics Release Inventory (TRI), a publicly available database of information on toxic chemical releases and other waste management activities from industrial and federal facilities arrayed by facility, zip code, county, industry, and many other variables. RSEI combines TRI information on the amount of releases with the other risk factors: estimates of toxicity and exposed populations. In addition to ranking numerous release situations, RSEI can quickly sort results in a number of ways and provide trends by chemical, industry, location, etc.

RSEI is a screening-level model because it uses simplifying assumptions to fill data gaps and reduce the complexity of calculations. RSEI should be used for screening level activities, such as trend analysis, or ranking regions, states, counties, industries, chemicals, facilities, or release pathways for follow-up activities. All RSEI results should be followed up with additional analysis. RSEI is not a formal risk assessment and does not describe a specific level of risk related to any particular disease; rather, it highlights situations that may lead to potential chronic human health risks.

Method to analyze and compare large amounts of data

RSEI uses risk factors to quickly and easily organize and evaluate large amounts of data, saving time and resources. In hours, or even minutes, users can perform analyses that would take days, weeks, or even months without RSEI.

RSEI risk scores can be used to:

Considerable resources can be saved by conducting preliminary analyses with the RSEI model to identify risk-related situations of high potential concern, which warrant further evaluation.

RSEI considers the following information:

This information is used to create numerical values (RSEI scores) , which can be added and compared in limitless ways to other RSEI scores to assess the relative hazard and risk of chemicals, facilities, regions, industries, or many other factors. The scores are for comparative purposes and are only meaningful when compared to other scores produced by RSEI. Again, the result does not provide a detailed or quantitative risk assessment, but offers a screening-level perspective for relative comparisons of chemical releases.

PC-based computer program

The RSEI model is a stand-alone Windows program that allows users to calculate results for any and all years of data and to present a variety of results in various geographic, graphic and tabular formats, as well as to export data to other programs. The program includes on-line help for all of the program functions. A User's Manual(PDF) (172 pp, 1.8 MB, About PDF) is also available.

RSEI is not supported for Windows Vista.

Created to facilitate priority-setting

In 1989, EPA outlined goals for establishing strategic planning processes at the Agency. Underlying this approach was the Agency's desire to set priorities and direct resources to areas with the greatest opportunity to achieve health and environmental risk reductions. As part of this initiative, the Administrator set forth a plan to develop indicators to track changes in environmental health impacts over time. Tracking these changes would allow the Agency to measure its progress in implementing environmental protection and pollution prevention programs. In addition, the Agency (and others) could use indicators to compare the relative contribution of particular chemicals, industries, and geographic regions and establish priorities for improving human health and the environment.

In response to the need for environmental indicators, and to take advantage of the rich data source offered by the Toxics Release Inventory (TRI), the Agency convened a workgroup to explore the development of an indicator or indicators based on TRI that could track changes in human health and environmental impacts better than reports of pounds of releases alone. Specifically, the approach would integrate toxicity, exposure and population considerations into the evaluation of releases. The Risk-Screening Environmental Indicators, which became known as "RSEI"—pronounced "REE-SEE"—was developed in response to this initiative.

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How RSEI Is Used

RSEI is very flexible. RSEI can be used to answer questions such as:

The RSEI model is easy to use and gives users enormous choices in selecting the types of releases for which they can get RSEI comparative scores, and make comparative tables, graphs, and lists. Examples of data analysis charts using RSEI are available. More detail about how to use RSEI appropriately can be found in How to Use—and Not Use—RSEI.

Read on about details of the characteristics of RSEI and how it works.

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