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About Chemical Characterizations

Note: EPA no longer updates this information, but it may be useful as a reference or resource.


Prior to the comprehensive approach to enhancing the Agency’s chemical management program announced by Administrator Jackson on September 29, 2009, EPA had used the Chemical Assessment and Management Program (ChAMP) to develop screening-level hazard, exposure, and risk characterizations for chemicals produced or imported in quantities of 25,000 pounds or greater a year to identify possible priorities for future Agency action. Although ChAMP has been superseded by the enhanced chemical management program, information developed under ChAMP is being used in the enhanced program.


Under ChAMP, between August 2007 and mid-2009, EPA developed screening-level hazard, exposure, and risk characterizations for some chemicals produced or imported in quantities of 25,000 pounds or greater a year. Based on those characterizations, EPA developed either a risk-based prioritization (RBP) or a hazard-based prioritization (HBP) for individual chemicals or a group of chemicals that were similar in some way, e.g., structure, properties, toxicity.

Those prioritizations did not constitute definitive determinations regarding hazard, risk, or the sufficiency of available information for any regulatory purpose, but were rather initial evaluations of data and understanding currently available to EPA.

Risk-Based Prioritizations (RBP)

EPA developed RBPs for chemicals that had adequate hazard and exposure/use information available. This typically included chemicals:

RBPs for individual chemicals or chemical categories included a qualitative prioritization decision and a qualitative screening-level risk characterization on which the prioritization decision was based. The screening-level risk characterization was developed based on:

A detailed description of the RBP process, including information on the rationale for characterizing hazard, exposure, and risk as high, medium, or low is available in the Methodology for Risk-Based Prioritization (PDF) (28 pp., 171 KB, About PDF).

Hazard-Based Prioritizations (HBP)

HBPs were developed primarily for chemicals identified as MPV on the 2006 IUR. Most MPV chemicals were produced below the production volume for which exposure and use information was required under the 2006 IUR (i.e., below 300,000 pounds per year) and were therefore less likely to have information available to develop exposure and risk characterizations to support a risk-based prioritization.

In some cases, HBPs were developed for chemicals that were HPV on the 2006 IUR. This occurred for chemicals that were not part of the HPV Challenge or OECD HPV programs and for which the hazard data that were used for developing an RBP (i.e., SIDS) were not currently available. In these cases, the HBP also included a summary of IUR production volume information, and if available (i.e. if chemical was produced at greater than 300,000 pounds per year), reported use information.

HBPs for individual chemicals or chemical clusters included a prioritization decision and its underlying screening-level hazard characterization. The screening-level hazard characterization was based on characterization of environmental fate and potential health and environmental hazards derived from existing data available to EPA. For many MPV chemicals, those data were limited. In such cases, EPA used a number of predictive tools and methods to characterize properties and hazards in developing fate and hazard characterizations.

A detailed description of the HBP process, including information on how chemicals were clustered and on how data gathering, review, and characterization were performed, is available in the Methodology for Hazard-Based Prioritization (PDF) (17 pp., 242 KB, About PDF).

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