Chrysotile, or white asbestos, is one of three types of asbestos that research shows is carcinogenic.

"If they rejected chrysotile, just think what the future has to hold in terms of other problem chemicals where there are commercial interests still at stake," said Clifton Curtis, the Washington, D.C.-based director of WWFs Global Toxics Program.

"Chrysotile unequivocally meets the Rotterdam Conventions requirements, and those governments opposing its listing blatantly disregarded the treaty obligation," said Curtis, who is attending the week-long Rotterdam Convention conference in Geneva.

Chemicals must have been banned or severely restricted in two regions of the world before they are considered for the list. There must then be a unanimous decision to add the chemical to the list, a move that requires exporting countries to inform potential buyers about the toxic chemical in order to get their consent. If the importing countries do not respond within about 18 months, trade can proceed.

The other two carcinogenic types of asbestos - blue and brown asbestos - are both on the Prior Informed Consent list.

Russia was the top producer of chrysotile in 2003, producing 878,000 tonnes, followed by Kazakhstan, China, Canada and Brazil.

Canada, which produced about 240,000 tonnes in 2003, tends to export most of its asbestos, said Laurie Kazan-Allen, founder and coordinator of the British-based International Ban Asbestos Secretariat.

Bernard Madé, director of chemicals control in the Canadian government's Environment Canada, said his government was concerned about misconceptions surrounding the convention.

"If added to (the list), that might be perceived by some countries as a signal to ban chrysotile," he said.

Canada, the only producing country of the top five to have ratified the Rotterdam Convention, once provided 35 percent of the world's asbestos, but now only three mines operating part-time provide about 5 percent, said Raynald Paré, president of the Canadian PRO Chrysotile Movement. Adding asbestos to the list would be like putting a ban on asbestos and further threaten the livelihood of about 1,200 people, Paré said.

Australia, Chile, the European Union and the United States are among the places to have banned domestic use of the chemical. The European Union exports only the asbestos it recovers from structures, and it requires consent of the buyers, said Klaus Berend, deputy head of the European Union's biotechnology and pesticides unit.

"This treaty is not about bans," said Carl Smith, vice president of the US-based Foundation for Advancements in Science and Education. "What it's about is information exchange, (and) if we can't even meet the standard of information exchange, we're in trouble."