||Relatively little is known about the toxicity of the many chemicals in existence today. This has prompted European Union regulatory authorities to launch a major chemicals testing program, known as Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). Although the driving force behind REACH is ostensibly based on the precautionary principle, in practice, the evidence suggests that it is oriented more toward risk assessment than precaution. In addition, the test methods used to assess chemical risk also raise questions about the efficacy of REACH in achieving its stated aims of protecting human health and the environment. These tests rely in large part on animal models. However, based on empirical evidence and on well-established principles of evolutionary biology and complex systems, the animal model fails as a predictive modality for humans. In turn, these concerns raise significant ethical and legal issues that must be addressed urgently.