Will We Know More or Less about Chemical Risks under REACH?

After a brief overview of the history of the regulation of chemicals, we summarize problems with the current European chemicals legislation that have led to the development of the new European regulation, REACH (Registration, Evaluation and Authorization of CHemicals). Two key aspects are (i) the problem of the large number of existing chemicals for which a practicable evaluation approach had to be found and (ii) the political intention to employ the precautionary principle as a guiding principle of the new regulation. The precautionary principle is related to the question of how risk assessors can deal with the lack of data, uncertainty, and non-knowledge. A particular aspect of dealing with fundamental uncertainties in chemical risk assessment is the use of hazard indicators, in particular for the properties persistence, bioaccumulation, and toxicity (PBT assessment). We analyze the way in which PBT assessments will have to be carried out under REACH. We estimate how many persistent chemicals might be expected among the existing chemicals and discuss uncertainties that impede the identification of these persistent chemicals. Our interpretation of how hazard assessment approaches are implemented in REACH is that the scientific development of hazard assessment methods has not yet provided the practical tools needed for a more consistent and workable approach to PBT assessment under REACH