Resources-Threats

Risk-Screening Environmental Indicators (RSEI) is a screening-level model that analyzes factors that contribute to human health risk. These factors include the amount of chemical released, the degree of toxicity, and the size of the exposed population. RSEI calculates scores to highlight releases that would potentially pose greater risk over a lifetime of exposure. Because of data limitations, RSEI is not a substitute for a site-specific risk assessment.

RSEI produces three types of results: pounds-based (releases), hazard-based, and risk-related (score).

￭ RSEI Pounds-based results are simply the amount of pounds reported by TRI facilities as released or transferred. Note that pounds in RSEI may differ from TRI pounds because they represent only those pounds modeled in RSEI and not all pounds from all releases. [The RSEI pounds-based results are the least informative of the three types of RSEI results because they ignore the toxicity of the chemicals released or transferred and the population exposed]

￭ RSEI Hazard-based results are calculated by multiplying the pounds released by the chemical-specific toxicity weight for the exposure route (oral or inhalation) associated with the release. Hazard-based results are only available for chemicals with RSEI toxicity weights and do not include any exposure modeling or population estimates. [The RSEI hazard-based results are useful in evaluating the comparative aggregate toxicity of chemicals released and transferred by facilities. However, these results do not consider the size of the exposed population]

￭ RSEI (Score) Risk-related results combine surrogate dose with toxicity weight and population estimate, producing a unit-less value or score. Risk-related results are not independently meaningful and should only be used comparatively in relation to other model results. [The RSEI scores or risk-related results are the most informative of the three types of RSEI results because they include consideration of quantity of chemicals released or transferred, the toxicity of chemicals released or transferred, and the size of the population exposed. Thus, two facilities that have the same RSEI hazard-based results may have different RSEI scores or risk-related results because of the size of the exposed population]