Butadiene--progress under the European Union Existing Substances Regulation.

A draft risk assessment report (RAR) for 1,3-butadiene has been produced by the UK under the European Union's Existing Substances Regulation (ESR). In line with the requirements of ESR, the RAR presents an evaluation of the hazards and risks of butadiene to human health (for workers, consumers and the general public) and to the environment. If as a result of the risk assessment, concerns for human health and/or the environment are identified, proposals for measures to reduce those risks may be developed. In relation to the human health elements of the ESR RAR for butadiene, the risk assessment involves a comparison of health effects against exposures in the three population sectors. The position arrived at on risk is described in qualitative rather than quantitative terms. For butadiene, the conclusion reached for the human health hazard assessment has been influenced significantly by both the animal and human data available. Species differences in toxicity, in particular with regard to mutagenicity and carcinogenicity, are considered along with the mechanistic arguments for these differences and their relevance for human health. The information presented in the RAR has been extensively discussed within the EU and a generally agreed position has been reached, with respect to human health hazard and risk. It is concluded that whilst the risks to human health at current exposure levels in the workplace, for consumers and following exposure via the environment are uncertain, there are concerns for human health effects for all three populations. Thus, there is a need to limit the risks. The next stage in the ESR process will be to consider what, if any, additional risk reduction measures may be required, taking into account existing control measures.