Regulations for the prevention of pollution by sewage from ships are set to enter into force in September 2003 following the ratification by Norway of Annex IV of MARPOL 73/78 Convention on marine pollution. Norway's ratification means the entry-into-force criteria for the Annex, set at 15 States whose combined merchant fleets constitute not less than 50 per cent of the world's merchant fleet by tonnage, have now been met.

The Annex sets out in detail how sewage should be treated or held aboard ship and the circumstances in which discharge into the sea may be allowed. It requires Parties to the Convention to provide adequate reception facilities for sewage and contains a model International Sewage Pollution Prevention Certificate to be issued by national shipping administrations to ships under their jurisdiction. The Annex will apply to ships engaged in international voyages. On entry into force it will have immediate effect on all new ships of 400 gross tonnage and above and new ships of less than 400 gross tonnage which are certified to carry more than 15 persons. It will apply to existing ships of 400 gross tonnage and above and of less than 400 gross tonnage and above but certified to carry more than 15 persons five years after the date of entry into force.