Exposure-based waiving under REACH.

Within the REACH framework, but also within OECD, there is understanding that for reasons of animal welfare, costs and logistics, it is important to limit the number of tests to be conducted. Exposure-based waiving (EBW) is a potentially important element in testing strategies. This publication describes criteria for exposure-based waiving as foreseen in the REACH regulation and gives more detail to the REACH requirements for exposure-based waiving The principle behind any EBW is that there are situations when human or environmental exposures are so low or infrequent that there is a very low probability that the acquisition of additional effect information may lead to an improvement in the ability to manage risk. EBW therefore is risk-based and needs thorough knowledge on exposure as well as on effects criteria. Both elements are discussed: exposure models are analysed and the uncertainty in their predictions discussed as well as no-effect criteria such as the threshold of toxicological concern. Examples of EBW are provided for environmental, consumer and worker exposure. REACH only allows EBW in a limited number of cases with constraints on tonnage levels, types of tests to be waived and the need for a thorough ES and exposure assessment throughout the life cycle of a chemical and for all human exposure routes and environmental pathways. EBW will only be considered a real option by industry if a cost-benefit analysis shows an advantage, which may heavily depend on the weighing factor one applies for the non-use of experimental animals.