Benchmark Dose Workshop: criteria for use of a benchmark dose to estimate a reference dose.

The purpose of the Benchmark Dose Workshop was to assess the feasibility and implications of replacing the no observed adverse effect level (NOAEL) with a benchmark dose (BMD) when deriving reference doses and concentrations (RfDs and RfCs). The workshop participants supported the use of the BMD method to remove many of the limitations inherent in using the NOAEL approach. Participants endorsed in general the use of a BMD for all quantal noncancer health effects and endorsed in particular the BMD for assessing developmental toxicity based on data presented at the workshop. The discussions of implementation recognized the need to demonstrate that changing from a NOAEL to a BMD gives the risk manager more certain information on which to base decisions. Most participants agreed that the current NOAEL-derived RfDs and RfCs are sufficiently protective and should only be changed as data become available for estimating a BMD. It was recognized that to achieve general acceptance of the BMD approach, it will have to be applied to a variety of endpoints.