OTTAWA - Canada has signed an international treaty that obligates it to follow the latest scientific evidence on the dangers of asbestos, a UN-affiliated labour organization is reminding the country this week.

But the NDP has unearthed a 2006 Health Canada recommendation that suggests the Harper government isn't even following the advice of its own experts on chrysotile asbestos.

New Democrat MP Pat Martin said the Health Canada report "clearly directs the government" to list the carcinogenic fibre under the Rotterdam Convention on hazardous chemicals.

"We now have proof that even Canadian officials believe chrysotile should be listed," said Martin, adding the information will be detailed at a news conference Tuesday on Parliament Hill.

The timing could be particularly embarrassing for the Conservative government.

A draft report from the Geneva-based International Labour Organization on the weekend singled out Canada as having a particular obligation to "keep abreast of technical progress and scientific knowledge" because it is one of the world's main producers of the cancer-causing material.

The report, a product of the 100th anniversary convention of the ILO in Geneva, notes that the Canadian government recognizes "the dangers of exposure to asbestos in the workplace" and that Canada is a signatory to the 1986 Asbestos Convention.

The convention obliges signatories to "take into account the evolution of scientific studies, knowledge and technology" since 1986, "as well as the findings of the World Health Organization, the ILO and other recognized organizations concerning the dangers of exposure to asbestos."

The report, although couched in dry bureaucratic language, helps set the stage for what could be a bruising month internationally for Canada on the asbestos file.

Canada continues to export the cancer-causing fibres, with the explicit approval and encouragement of the Harper government in Ottawa and the Liberal provincial government in Quebec City. The industry employs several hundred workers in Thetford Mines, Que., and nearby Asbestos.

"The only party that defends the chrysotile industry is our party, the Conservative party," Prime Minister Stephen Harper said in April during an election campaign stop in Asbestos, Que.

Yet asbestos use is sharply controlled in Canada and taxpayers are paying tens of millions of dollars to have it removed from public buildings, including Parliament and the prime minister's official residence.

Despite domestic controls that amount to a near ban, Canada has been working for years to keep chrysotile asbestos off a list of hazardous substances under the 2004 Rotterdam Convention, to which Canada is also a signatory.

Harper asserted on the campaign trail that asbestos use "is permitted internationally under conditions of safe and controlled use."

The prime minister neglected to add that Canada is actively blocking asbestos from being included under a convention designed "to promote shared responsibility and co-operative efforts among parties in the international trade of certain hazardous chemicals."

Being listed on the convention doesn't stop the trade in a product.

"It just means you have to inform the people ... buying to take health and safety protocols," said the NDP's Martin.

Canada's position, he said, is "you're not allowed to put a skull and cross bones on this Class A carcinogen because it might interfere with your ability to sell it if people knew it was deadly. How offensive is that?"

The issue comes up again on June 20 when international delegations meet in Geneva to update the Rotterdam Convention -- with asbestos dominating the agenda. Environment Canada will represent the federal government.

Official summit documents, prepared in advance of the Swiss conference and posted online, suggest how far offside Canada is from international opinion.

The documents note "with appreciation the work of the Chemical Review Committee in its consideration of chrysotile asbestos, in particular the technical quality and comprehensiveness of the draft decision guidance document."

Not only is asbestos -- again -- one of four substances recommended for hazardous listing, the summit plans to re-examine the very system used to endorse such recommendations.

The consensus model used under the Rotterdam Convention is allowing a small number of countries to block the hazardous listing of asbestos against the wishes of the vast majority.

The conference documents suggest the impasse is undermining the entire treaty:

"Many representatives expressed their disappointment in that regard, saying that it was an unfortunate precedent that had implications for the Convention's continued effectiveness and that it restricted the available information on the basis of which Parties, particularly those with developing or transitional economies, could make informed decisions on the use of that chemical."

The asbestos impasse is forcing delegates in Geneva to consider two proposed options: amend the Rotterdam Convention itself to change the consensus process; or create a new annex of dangerous chemicals on which at least three quarters of convention signatories agree but a full consensus can't be reached.

The latter, says the document, "would create a dual or parallel system" with some countries opting out.

"Assuming, however, that only those that have opposed adding chrysotile asbestos to Annex III would opt out, it would be expected that the great majority of parties would agree to be bound by the obligations of the Convention for these chemicals."