RSEI Results Definitions
On this page, find definitions for the following results produced by EPA's Risk-Screening Environmental Indicators (RSEI) model:
- TRI Pounds
- RSEI Pounds
- Cancer Hazard
- NonCancer Hazard
- RSEI Hazard
- Cancer Score
- NonCancer Score
- RSEI Score
- Toxicity-Weighted Concentration
TRI Pounds
Chemical release or transfer as reported to TRI in pounds per year.
RSEI Pounds
Chemical release or transfer as reported to TRI in pounds per year, calculated only for RSEI modeled media, or the kinds of releases and transfers that RSEI models (stack and fugitive air releases, direct water releases, and transfers to publicly-owned treatment works (POTWs) and off-site incineration).
Cancer Hazard
The pounds released or transferred, weighted by the chemical's toxicity for carcinogenic effects.
Direct water releases and transfers to publicly-owned treatment works (POTWs) use a toxicity weight based on the oral slope factor for the chemical. Air releases and off-site transfers to incineration use a toxicity weight based on the chemical's inhalation unit risk. If there is not data for a pathway, then the cancer hazard is zero. No modeling or partitioning is performed.
NonCancer Hazard
The pounds released or transferred, weighted by the chemical's toxicity for noncarcinogenic effects.
Direct water releases and transfers to publicly-owned treatment works (POTWs) use a toxicity weight based on the reference dose for the chemical. Air releases and off-site transfers to incineration use a toxicity weight based on the chemical's reference concentration. If there are no data for a pathway, then the noncancer hazard is zero. No modeling or partitioning is performed.
RSEI Hazard
The pounds released or transferred, weighted by the higher of the cancer/noncancer toxicity weights for the chemical.
Direct water releases and transfers to publicly-owned treatment works (POTWs) use the higher of the oral slope factor toxicity weight or the reference dose toxicity weight for the chemical. Air releases and off-site transfers to incineration use the higher of the inhalation unit risk toxicity weight or the reference concentration toxicity weight. If all toxicity data for an (air or water) pathway are missing, the data for the other pathway are adopted. No modeling or partitioning is performed.
Cancer Score
A unitless result that accounts for the size of the release, the chemical's toxicity for carcinogenic effects, the fate and transport of the chemical through the environment, and the size and location of the exposed population.
The cancer score is calculated as the product of the estimated dose (estimated through media-specific modeling), the cancer toxicity weight and the number of potentially exposed people. Direct water releases use a toxicity weight based on the oral slope factor for the chemical. Air releases and off-site transfers to incineration use a toxicity weight based on the chemical's inhalation unit risk. Transfers to publicly-owned treatment works (POTWs) are partitioned using chemical-specific rates to air and water. If there are no data for a pathway, then the cancer score is zero.
NonCancer Score
A unitless result that accounts for the size of the release, the chemical's toxicity for noncarcinogenic effects, the fate and transport of the chemical through the environment, and the size and location of the exposed population.
The noncancer score is calculated as the product of the estimated dose (estimated through media-specific modeling), the noncancer toxicity weight and the number of potentially exposed people. Direct water releases use a toxicity weight based on the reference dose for the chemical. Air releases and off-site transfers to incineration use a toxicity weight based on the chemical's reference concentration. Transfers to publicly-owned treatment works (POTWs) are partitioned using chemical-specific rates to air and water. If there are no data for a pathway, then the noncancer score is zero.
RSEI Score
A unitless result that accounts for the size of the release, the chemical's toxicity, the fate and transport of the chemical through the environment, and the size and location of the exposed population
The RSEI Score is calculated as the product of the estimated dose (estimated through media-specific modeling), the higher of the cancer/noncancer toxicity weight for each pathway, and the number of potentially exposed people. Direct water releases and transfers to publicly-owned treatment works (POTWs) use the higher of the oral slope factor toxicity weight or the reference dose toxicity weight for the chemical. Air releases and off-site transfers to incineration use the higher of the inhalation unit risk toxicity weight or the reference concentration toxicity weight. If all toxicity data for a (water or air) pathway are missing, the data for the other pathway are adopted. Transfers to POTWs are partitioned using chemical-specific rates to air and water.
Toxicity-Weighted Concentration
Used in Microdata, a result that includes the fate and transport of the chemical through the environment and the chemical’s toxicity.
Direct water releases and transfers to publicly-owned treatment works (POTWs) use the higher of the oral slope factor toxicity weight or the reference dose toxicity weight for the chemical. Air releases and off-site transfers to incineration use the higher of the inhalation unit risk toxicity weight or the reference concentration toxicity weight. If all toxicity data for an (air or water) pathway are missing, the data for the other pathway are adopted.