The 1992 OSPAR convention is the current instrument guiding international cooperation on the protection of the marine environment of the North-East Atlantic. It combined and up-dated the 1972 Oslo Convention on dumping waste at sea and the 1974 Paris Convention on land-based sources of marine pollution. The signatories to the convention are Belgium, Denmark, Finland, France, Germany, Iceland, Ireland, the Netherlands, Norway, Portugal, Spain, Sweden, UK and Northern Ireland; the EU is also a signatory, as are Luxembourg and Switzerland. OSPAR has published lists of environmentally acceptable and unacceptable products, referred to as the “green,” “grey” and “black” lists. The “black list” covers products considered unsuitable for discharge and includes mercury, cadmium and persistent oils and hydrocarbons of a petroleum origin. The OSPAR operating principles for regulating offshore discharges take account of the persistence, toxicity or other noxious properties and tendency to bio-accumulation of the chemicals in drilling wastes. The convention is based on a number of principles, including: the precautionary principle; the polluter pays principle; best available techniques (BAT) and best environmental practice (BEP), including clean technology;