A new IMO convention will prohibit the use of harmful organotins in antifoul paints used on ships and will establish a mechanism to prevent the potential future use of other harmful substances in anti-fouling systems.

The International Convention on the control of harmful anti-fouling systems on ships was adopted on 5 October 2001 at the end of a five-day Diplomatic Conference held at IMO Headquarters in London.

Under the terms of the new Convention, Parties to the Convention are required to prohibit and/or restrict the use of harmful anti-fouling systems on ships flying their flag, as well as ships not entitled to fly their flag but which operate under their authority and all ships that enter a port, shipyard or offshore terminal of a Party.

Ships of above 400 gross tonnage and above engaged in international voyages will be required to undergo an initial survey before the ship is put into service or before the International Anti-fouling System Certificate is issued for the first time; and a survey when the anti-fouling systems are changed or replaced.

Ships of 24 metres or more in length but less than 400 gross tonnage engaged in international voyages will have to carry a Declaration on Anti-fouling Systems signed by the owner or authorised agent. The Declaration will have to be accompanied by appropriate documentation such as a paint receipt or contractor invoice.

Anti-fouling systems to be prohibited or controlled will be listed in an annex (Annex 1) to the Convention, which will be updated as and when necessary.

The harmful environmental effects of organotin compounds were recognised in 1989. In 1990 IMO’s Marine Environment Protection Committee (MEPC) adopted a resolution which recommended that Governments adopt measures to eliminate the use of anti-fouling paint containing TBT on non-aluminium hulled vessels of less than 25 metres in length and eliminate the use of anti-fouling paints with a leaching rate of more than four microgrammes of TBT per day.

The new convention will enter into force 12 months after 25 States representing 25 percent of the world’s merchant shipping tonnage have ratified it.