The Precautionary Principle

This note describes the precautionary principle and its key tenets, highlights challenges associated with its use, and includes many examples of its application, primarily within the realm of regulating activities based on the risk of harm to human health and the environment. Appendices provide detailed examples of how the precautionary principle has been applied to regulations in three key industries: agriculture, chemicals, and pharmaceuticals. Describes various forms of the precautionary principle, its widespread adoption in international agreements, its distinction from cost-benefit analysis, its shift of the burden of proving that activities are safe from regulators to industry, and the importance of considering Type I and Type II errors and status quo bias when contemplating whether to evoke the precautionary principle.