WASHINGTON – A treaty that forbids the maritime use of what the Environmental Protection Agency deems the most toxic chemical ever deliberately released into the world’s waters is expected to be ratified within days.
It bans the poison tributyltin, a cheap and effective barnacle and algae killer once used on nearly all the world’s 30,000 commercial ships. The treaty also sets up a system for future testing and curbs on other hull biocides worldwide.
By 1995, more than 500 research papers worldwide had linked tributyltin, known as TBT, to adverse environmental or health effects. The most worrisome were “profound reproductive effects” coupled with diminished marine-species populations, according to Jill Bloom, an EPA chemical-review manager who worked on the treaty.
“It’s very, very bad stuff,” said Lindy Johnson, a National Oceanographic and Atmospheric Administration lawyer who worked with Bloom.
“It’s a tremendous victory for the marine environment,” said Simon Walmsley, the head of marine programs at the World Wildlife Fund’s London office, “but one that is long overdue.”
The ban on tributyltin signals a green turn for the U.S. and European chemical and paint and coatings industries, which endorsed the deal, as well as cruise lines, freighter and container fleets, and shipyard and marina operators.
Their commitment will be tested further by other pending maritime environmental concerns, including, in California, growing resistance to copper-based substitutes for TBT. Other challenges include ballast water releases and stack emissions from ships’ massive engines.
Although an EPA official orchestrated the TBT treaty’s drafting and key federal agencies have agreed on regulations to enforce it, the ban has yet to clear the White House Office of Management and Budget. Panama or the Marshall Islands are expected to cast the decisive vote before the United Nations International Maritime Organization in London, which oversees the treaty.
Washington’s endorsement is expected in a few months. Its pace on a pact that was completed in October 2001 vexes Robert Martin, a treaty negotiator. Martin is the global marine-business director for Arch Chemicals Inc. of Norwalk, Conn., which didn’t make TBT but sells the leading biocidal substitutes for it.
“It’d be good for the U.S. to be involved with an environmental treaty, especially in this administration,” Martin said.
TBT’s use first became worrisome in 1976, when scientists linked it to disorders in mollusks in the Arcachon Basin in western France, where shellfish beds adjoined a marina.
Biocides such as TBT, a clear liquid that smells like gasoline, are mixed into the bottom paint or coating for marine hulls. The most sophisticated marine coatings these days are made to slough off like soap from a bar, but very slowly. That keeps a ship’s underwater surfaces sleek while dispensing just enough biocide to kill barnacles, algae and grasses.
Yachtsmen, sailboat racers, charter captains and commercial shippers consider biocides such as TBT essential because they enable hulls to slip more easily through the water. By one industry estimate, such coatings save commercial skippers $6 billion a year by improving speed and fuel economy and making dry-docking less frequent.
Environmentalists have a reason to like biocides, too: They prevent ships from transporting invasive species such as zebra mussels from one port to another.
Initially, TBT’s biggest problem was thought to be the untold thousands of recreational boats that rained tiny amounts of the poison onto the bottoms of harbors and marinas that they rarely left. In 1988, the United States banned TBT on vessels that are less than 82 feet long.
Major U.S. and European makers voluntarily stopped producing TBT in January 2001, and its presence in marine organisms is declining. But it continues to be widely used in much of Asia and on ships built or overhauled there that ply the world’s seas. Indeed, China only recently pledged to stop adding DDT, a far more infamous biocide, to its hull-protecting marine paints.