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Use Cluster Scoring System (UCSS)

What is the Use Cluster Scoring System?

The Use Cluster Scoring System (UCSS) is a computer-based, risk-screening system with information about nearly 3,200 chemicals and the 380 clusters -- or families -- into which these chemicals are grouped. For example, instead of considering a single chemical that happens to be a paint stripper, the cluster of chemicals that perform as paint strippers is considered. The UCSS accesses hazard and exposure data that is extracted from the Toxics Release Inventory (TRI), the Integrated Risk Information System (IRIS), and other readily accessible risk assessment related databases. The UCSS then uses a simple system to score and rank chemicals and their respective clusters. The program was developed to identify clusters of chemicals of potential concern to EPA.

What information does the UCSS contain?

UCSS contains hazard and exposure data from a variety of different sources for the 3,200 chemicals and 380 clusters already studied. For these chemicals and clusters, toxicity scores for the chemicals and clusters have been calculated. The UCSS can also be used to analyze chemical clusters not yet reviewed by EPA. To analyze new clusters, users must first research and collect information about each chemical within a cluster. The kinds of information to be input include: potential for human and ecological exposure; potential for adverse human and environmental effects; potential for pollution prevention; and EPA interest. With this information, the program can then calculate human and environmental hazard and exposure rating scores for each chemical. These individual toxicity scores are translated into an overall cluster score, which is an indicator of potential concern for the use cluster.

Why was the UCSS developed?

The UCSS was developed to help the EPA screen and prioritize chemicals. The UCSS is a tool used by the EPA to focus on high priority chemicals and clusters for effective risk reduction with targeted industries and chemical users.

How can citizen groups use the UCSS?

When EPA releases the software program to the public, citizens will be able to use the UCSS as a reference resource. It provides access to a compilation of information about nearly 3,200 chemicals. With assistance from chemists, community groups will also be able to use the software to estimate toxicity scores for similar chemicals and clusters not yet studied by EPA.

How can I obtain additional information about the UCSS?

For additional information about the Use Cluster Scoring System, contact:

Franklyn Hall
EPA OPPT Economics, Exposure & Technology Division
Mail Code 7406
1200 Pennsylvania Avenue, NW
Washington, DC 20460
Telephone: 202-564-8522
E-mail: hall.franklyn@epa.gov

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