After years of pressure from environmentalists, the world's ship-owners were on Friday told to stop painting the bottoms of their vessels with the anti-fouling agent tributyl tin (TBT).
This is despite continuing concern about the effectiveness of alternatives in removing barnacles and other sea creatures, which makes ships slower and heavier.
The problem with TBT-based anti-fouling paint is that it slowly leaches into the water. There it has been shown to cause sex-changes in whelks and deformation in oysters since the 1970s.
The ban was welcomed by green campaigners. But the Organotin Environmental Program Association (ORTEP), an industry lobby organisation, warned that banning TBT paints could cause an increase in the number of alien species that spread round the world on the hulls of ships, causing ecological havoc. It also estimates that removing TBT-based paints from the world's ships could cost up to $1 billion.
Covering up
The move to ban the paints came at a meeting of the UN's London-based International Maritime Organisation. The agreement gives shipping companies until January 2003 to stop using the paint, and a further five years to cover up existing TBT paint on ships' hulls.
But the first deadline will almost certainly be delayed. For the agreement also says the ban will not enter into force until a year after at least 25 states with 25 per cent of the world's shipping tonnage ratify.
On Thursday at the IMO, the Worldwide Fund for Nature launched a club of shipping companies that promise to ban the paint before 2003. The "Group 2003" has four founding members: two German and two Scandinavian.
Looking for alternatives
Most European countries have already banned the use of TBT on small boats, because of the damage it causes in marinas and coastal waters. But the IMO decision will eventually extend that ban to ocean-going vessels of more than 400 tonnes.
However, there is continuing argument about the efficacy of alternative paints in keeping marine organisms from attaching themselves to ship hulls. After trials on a series of alternative paints, the WWF recently concluded that while "some of these biocide-free paints provide promising alternatives ... results vary depending on the ships' operating conditions."
Nonetheless, Simon Vowles, marine policy officer for WWF in the UK, said that the formation of Group 2003 "obliterates the myth that phasing out TBT is impossible". And there are hopes that, with a ban agreed, paint manufacturers will redouble their efforts to make better non-toxic alternatives.
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