The precautionary principle relates to the handling scientific information that is often incomplete, uncertain, and contested. It states that if an action or policy has suspected risk of causing harm to the public or to the environment, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action.

One of the primary foundations of the precautionary principle stems from the work of the "Earth Summit" in 1992:

In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

Within everyday risk management, the precautionary principle should be applied only in very particular circumstances. It should not be applied to well-known hazards where the broad level of risk has been established