EPA Implementation of New Methods for Noncancer Risk Assessment. C. A. Kimmel, Human Health Assessment Group, Office of Health and Environmental Assessment, and Risk Assessment Forum, U.S. EPA, Washington, DC 20460
The application of new methods for quantitative approaches to noncancer risk assessment is currently a focus of major activity within the EPA. These efforts began several years ago with the proposal of the benchmark dose (BMD) approach (Crump, 1984) and its evaluation in several publications. The BMD approach was then applied to a number of data sets in an effort to explore the utility and practicality of implementing this approach within the regulatory setting. The EPA's Science Advisory Board has urged the Agency to begin implementation, and as a result the Guidelines for Developmental Toxicity Risk Assessment (1991) indicated an intent to do so. Other noncancer risk assessment guidelines on reproductive toxicity and neurotoxicity are being developed and discuss this approach as well. More recently, EPA has co-sponsored workshops with the California EPA, and with the American Industrial Health Council and the ILSI Risk Science Institute to evaluate various approaches to deriving the BMD, its use in calculating the reference dose (RfD) or reference concentration (RfC), and issues for implementation. Many of the presentations in this symposium represent work that has been supported by the EPA in its search for improved quantitative risk assessment methods. Current efforts within the Agency include the development of guidance for application of the BMD, efforts to begin implementation within the RfD/RfC process, and evaluation of software design and availability. In addition, there is interest in applying similar approaches in certain cases for cancer risk assessment when there is evidence for a threshold mechanism.