Precautionary Principle states that when an activity causes some threat or harm to the public or the environment, general precautionary measures should be taken. When a scientific investigation proves that there is a possible risk in doing some activity, then this principle should be applied.
Internationally, one of the most important expression of the Precautionary principle is the Rio Declaration from the United Nations Conference on Environment and Development. Principle 15 of the Rio Declaration reads:
“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.”
This principle is applied in the context of human activities on the environment and human health.
In U.S the precautionary principle is not expressly mentioned in any laws or policies. Despite U.S. acceptance of the precautionary principle in international treaties and other statements, little work has been done to implement this principle.
However, some U.S. laws have a precautionary nature. For example, The Occupational Safety and health Act (OSHA) requires precautionary actions whenever chemical used in the workplace is suspected of causing cancer in animals.