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TBT-Free Paint

Going... Going... Almost Gone

Like the dinosaurs and the dodo, tributyltin antifouling paints will soon be extinct?

By Capt. Ken Kreisler — April 2003

   


 More of this Feature

• Part 1: TBT
• Part 2: TBT
• Part 3: TBT


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Tin. People have used it since antiquity. It’s been found in the tombs of ancient Egyptians, and large amounts of it were imported to Europe during the time of the Roman Empire, from Cornwall, England, where even today it is still found in great quantities. It is the 49th-most abundant element in the Earth’s crust and is used as a protective coating for copper. It is combined with copper to make bronze and with titanium for use in the aerospace industry, and is an ingredient in insecticides. Where it soon will not be found, in the form of tributyltin (TBT), is in antifouling paint.

In 1989 the International Marine Organization (IMO) first recognized the detrimental effects TBT was having on such nontargeted organisms as oysters, clams, and snails. A year later the IMO’s Marine Environment Protection Committee adopted a resolution recommending elimination of nonantifouling paint containing TBT on aluminum-hulled vessels of less than 25 meters (82 feet). At its Antifouling System Convention in October 2001, the IMO approved a treaty, which among other things prohibits the application of antifouling paints containing TBT and, as of January 1, 2008, bans TBT on all ships unless they are coated with approved sealer coats. The treaty goes into effect once it is ratified by at least 25 countries with a combined total of at least 25 percent of the world’s shipping tonnage. The United States signed the treaty on December 17, 2002.

The European Union (EU) has already taken action on its own. As of the end of 2002, TBT cannot be applied within the EU, and the EU Parliament and the Council of Ministers have approved a regulation that prohibits application of TBT bottom paint to ships flying the flags of EU countries anywhere in the world, effective this month.

TBT was valued for its effectiveness in preventing sea life from attaching to a hull as well as its compatibility with aluminum. It was primarily used in self-polishing antifouling coatings, known as ablatives, that release biocide at a controlled rate, much like water wearing away a bar of soap. Today, while the verdict is still out on just how harmful TBT is to the environment, it is classified as a restricted-use pesticide, meaning applicators must have a permit or license to use it.

Once the treaty is in effect, U.S. port authorities and the Coast Guard will monitor compliance by checking any yacht 79 feet or longer and less than 400 gross tons entering from abroad to see that it has a legal document signed by the owner or captain stating that the hull is in compliance. Vessels of more than 400 gross tons can be surveyed and a hull sampling taken by a representative of the vessel’s flag state, who then issues a certificate of compliance. Any vessel lacking such documentation can be denied entry or be subject to a hefty tax, both of which can cause a shipping line to lose significant revenue.

Next page > Tributyltin, Part 2 > Page 1, 2, 3

This article originally appeared in the March 2003 issue of Power & Motoryacht magazine.

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