TORONTO - Erica Casselman still struggles to find words to describe how she felt watching an aggressive form of asbestos cancer kill her husband.

She says the experience has shattered "the very core" of her existence -- and she believes the tragedy that unravelled her life was preventable.

Critics say many more families risk finding themselves in Casselman's situation as Quebec continues to mine cancer-causing chrysotile asbestos and export it to Third World countries.

At an international conference in Rome this week on hazardous materials, chrysotile asbestos failed to be included on a list of dangerous substances because of a lack of consensus among the participating countries. Canadian officials were present but did not take part in the discussions.

"It's just all so political, it's scary," said Casselman, 56, who lives in Salmon Arm, B.C. "You talk about the money or the people losing their jobs in Quebec but ... how much is Jim's life worth? It's surely worth a lot more than that.

"This has affected me for the rest of my life. I will never be at peace until I die."

Casselman's husband Jim died at the age of 64, 18 months after being diagnosed with mesothelioma, a painful and deadly malignancy in the lining of the chest wall.

A competitive swimmer and avid sportsman, he had been surprised to find how exhausted he was after competing in the World Masters Games in Edmonton in 2005. After three months of what he thought was a bad head cold and breathing problems, he was diagnosed with cancer.

"There's no words to explain that anguish when the doctors sit there and they say, `You've got three to six months left to live,"' Casselman said.

"When you see a man ... who has given so much to his family and the community dissolve in tears just praying that he could live a little bit longer than six months because he just wasn't done loving us ... it's just the most indescribable feeling."

Jim Casselman ended up living more than a year longer, enduring three surgeries, multiple rounds of chemotherapy and a clinical trial.

His cancer temporarily went into remission, which gave the couple and their two 20-something sons, Ivan and Graham, seven months to travel, hike, sail and spend as much time together as possible.

But after the third surgery, Jim Casselman contracted C. difficile at the hospital, and the family knew time was running out.

He died on April 15, 2007, of a pulmonary embolism -- something his wife has come to consider a "gift" because it spared him the painful end stages of mesothelioma.

"It's a very ugly death and Jim was terrified of that," she said.

The cancer was traced back to the Salmon Arm junior high school in which Jim worked as a shop and math teacher in the late 1970s.

But there have also been several cases involving workers in the country's mines, as well as concerns about the use of the controversial fibre in schools, hospitals and roads.

Manitoba is spending up $5 million to look for asbestos, PCBs and mercury in its public housing buildings. In Calgary, some aldermen raised concerns in July after a report revealed dozens of city roads contained asbestos. In Ottawa, workers are removing chrysotile asbestos from the Parliament buildings as part of a $1-billion renovation project.

Yet in the lead-up to the Rotterdam Convention in Rome, which wrapped up Friday, Canada declined to clarify its official position on chrysotile asbestos. It remained silent during the debate, even though it is one of the biggest exporters of the controversial fibre.

Canada has maintained chrysotile asbestos can be used safely, even though the fibre has been recognized as a cancer-causing agent by a number of countries as well as the World Health Organization -- which estimates the substance causes 100,000 preventable deaths annually around the world. The Canadian Medical Association Journal also recently ran an editorial slamming Ottawa for promoting exports of the potentially harmful material.

Asbestos is no longer used in Canada, but it is mined in Quebec and exported to developing countries in a $100-million-a-year industry that employs 700 people.

Ottawa has spent about $20 million since the mid-1980s to promote asbestos use. Chrysotile is the only form of asbestos that is still used commercially, primarily as an additive to cement.

NDP MP Pat Martin, who was in Rome for the convention, said the fact Canada "wants to continue exporting it and doesn't even want to warn the people they're selling it to that it's a class A carcinogenic is just offensive to the sensibilities of any Canadian."

"Our health and safety regulations are that no Canadian should be exposed to a single fibre of asbestos, including chrysotile," said Martin, a former asbestos miner.

"Yet we dump 200,000 tonnes a year into Third World and developing countries and object to having warning labels put on it.

"Canada should hang its head in shame."

Martin believes the mines in Quebec are being kept open due to government subsidies and intense political pressure.

"You're not doing those 700 miners that are left in Quebec any favours by sending them to work in the asbestos mines," he said.

A year and a half after her husband's death, Casselman is still struggling to cope.

"Every aspect of my life has changed," she said. "I can't prepare a meal because Jim and I would do it together. I can hardly do laundry because his clothes aren't there.

"Since his death it has been a struggle for all three of us to find our way without Jim. I don't know where I belong, who I am."