The federal Conservative party has sent a threatening email to the widow of an asbestos victim in the latest chapter of Canada's debate over the hazardous mineral.

A top Tory official is warning the woman to stop using the party logo in an online ad campaign against the controversial industry — a campaign she started after her husband died of an asbestos-related cancer.

Michaela Keyserlingk, whose husband Robert died in 2009 of mesothelioma, has been running an online banner since the spring that reads, "Canada is the only western country that still exports deadly asbestos!"

Conservative party executive director Dan Hilton warned Keyserlingk to stop using the Tory symbol immediately.

"Failure to do so may result in further action," Hilton wrote in a July 29 email which carried the subject title, "Unauthorized use of trademark." The email, which The Canadian Press obtained from Keyserlingk, went on to advise her: "Please govern yourself accordingly."

Conservatives say asbestos is safe

The exchange comes as Canada faces intensifying international criticism over its asbestos exports and the Quebec government mulls whether to help revive one of the country's last-remaining mines — a decision that could come  as early as Monday.

Canada, which barely uses the hazardous material domestically, exports the bulk of its asbestos to poor countries.

Industry proponents insist the material is safe if properly handled — but its critics stress that the product is used mainly in developing countries where safety standards are haphazard.

A growing chorus of health experts, and people like Keyserlingk, want to see the industry shuttered for good.

The Conservatives, meanwhile, have steadfastly defended asbestos exports and insist they're safe when handled properly.

Keyserlingk's blurb, which she says appears randomly on Canadian web pages, is flanked with a "DANGER" warning label and an image of the Tories' official symbol: a blue letter C with a Maple Leaf.

It also directs readers to her website.

"I just want to have the asbestos trade stopped because it's such a horrible death," said Keyserlingk, who doesn't belong to any organization and pays more than $300 per month for the ad out of her pocket.

"It's just so terrible — and to even contemplate doing that to other people is unforgivable."

When asked about the ad, the Conservative party stood its ground.

"The Conservative logo is a trademark of the Conservative Party of Canada and we do not allow its unauthorized use," party spokesman Fred DeLorey wrote in an email to The Canadian Press.

Hilton did not respond to requests for an interview.

Industry in decline

Canada's asbestos industry has nearly disappeared in recent decades amid health concerns. The Canadian Cancer Society estimates that more than 100,000 people die worldwide every year from occupational exposure to asbestos.

The vast majority of Canadian asbestos exports come from an operation in Thetford Mines, Que., but investors are hoping to save the Jeffrey Mine in nearby Asbestos, which has operated infrequently in recent years.

Quebec has promised to back a contentious $58-million bank loan to prolong the life of Jeffrey Mine for another 25 years, as long as the company can find enough private financing.

The company has requested an extension for the Monday deadline set by the government.

Whatever happens, Robert Keyserlingk's wife of 47 years will keep fighting. "I owe him not to give up because he never gave up," she said.