From MarineSpecies Introduced Traits Wiki
The principle of avoiding possible environmental damage when the scientific evidence for acting is inconclusive but the potential damage could be great..
The Maastricht Treaty adopted the Precautionary Principle as a fundamental element of environmental policy. (Article III-233 of the draft Treaty establishing a constitution for Europe.)
- Planning portal, UK. http://www.planningportal.gov.uk/england/professionals/en/1115310689486.html