Canadian Miners Face a Greater Risk of Mesothelioma Than Other Workers

Written by Michelle Whitmer for the The Mesothelioma Center at Asbestos.com

Exposure to asbestos is the primary cause of mesothelioma, a rare form of terminal cancer. Occupational exposure is the most common way Canadians encounter the toxic mineral. This aggressive cancer is more frequently diagnosed in miners, construction workers, insulators, boiler workers, and chemical manufacturers than other occupations in Canada.

Who is at risk?

Non-metal miners in Canada face a greater risk of mesothelioma than any other worker in the country. Asbestos mining in Canada ended in 2012, but other types of non-metal mining continue to expose miners to asbestos. 

Miners, millers, truck drivers, and ship loaders faced high levels of exposure at mining operations throughout Canada. Factory workers also handled asbestos ore from mines that went into asbestos products.

Several dozen asbestos mines once operated in Canada, and it was the largest exporter of asbestos to the United States. Quebec was among the largest mining areas, but mining operations in British Columbia, Newfoundland, and Yukon also exposed many workers to asbestos. The first asbestos mine opened in 1874 in the province of Quebec, and the final asbestos mines to shut down included Jeffrey Mine in Val-des-Sources and the Lac d’amiante du Canada, or Thetford Mine.

Ron Green developed pleural mesothelioma from working for 14 months in a Johns Manville factory that operated the Thetford Mine. 

“It was not something I worried about, but it stayed in the back of my mind, so I wasn’t caught totally off guard with the diagnosis,” he told The Mesothelioma Center at Asbestos.com. “It just took 48 years before the effects finally showed up.”

Some mining areas are contaminated with asbestos mining residue. Residents in these areas face increased health risks as a result. A 2022 study found Quebec’s Lake Becancour contains up to 4.4 per cent asbestos by weight in sediment. 

Rates of mesothelioma in miners

Mining in Canada between 1983 and 2014 resulted in varying rates of mesothelioma depending on the type of work miners performed. Asbestos miners carried the highest risk and were 240 times more likely to develop mesothelioma than the general population. Non-metal miners were about 12 times more likely to get mesothelioma. Asbestos contamination in mineral deposits may explain this risk.

Canadian mesothelioma patient Jayda K. developed peritoneal mesothelioma from secondary exposure through her father, who worked at a coal mine. His work involved using asbestos products and machinery parts, and he unknowingly carried asbestos fibers home on his clothing.

She developed abdominal symptoms at a young age, but doctors often dismissed her pain, which delayed her diagnosis. “You have to advocate for yourself, and if you get turned down, just keep trying,” she said.

Interestingly, metal miners had a risk level close to the general population, but their risk of asbestosis was slightly higher. Asbestosis is a progressive lung disease involving scarring and inflammation. 

All types of asbestos cause mesothelioma

Most mesothelioma cases in Quebec’s mine workers have been associated with exposure to a type of asbestos called tremolite. Supporters of the chrysotile asbestos industry believe it doesn’t cause mesothelioma. They say tremolite contamination of chrysotile causes mesothelioma, but research has shown otherwise. 

For example, a 2011 case report of peritoneal mesothelioma in a mine mill worker shows the patient was employed at a chrysotile Carey mine in Quebec. A 1995 study showed chrysotile fibers in the lungs of 10 out of 12 mesothelioma patients who worked as miners and millers in Val-des-Sources, once known as Asbestos, Quebec. 

Preventing and treating mesothelioma in miners

Preventing asbestos exposure is the best way to lower the risk of mesothelioma. Canadian miners should follow safety measures to prevent exposure, such as wearing personal protective equipment and avoiding asbestos products. Mining products and machinery that may contain asbestos include gaskets, insulation, brakes, clutches and transite panels.

Former miners should inform their doctors about prior asbestos exposure and request cancer screenings. Diagnosing and treating mesothelioma early can improve treatment outcomes and extend survival. Watch for signs of mesothelioma, which include difficulty breathing, cough, chest or abdominal pain, weight loss and fatigue. 

The most effective treatments for mesothelioma include surgery, immunotherapy, chemotherapy and radiation. Most people live about a year with the disease, but aggressive treatment helps at least 12 per cent of patients live longer than five years. 

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References:

• DeBono, N. L., Warden, H., Logar-Henderson, C., Shakik, S., Dakouo, M., MacLeod, J., & Demers, P. A. (2021). Incidence of mesothelioma and asbestosis by occupation in a diverse workforce. Retrieved from https://doi.org/10.1002/ajim.23245
• Egilman, D., & Menéndez, L. M. (2011). A case of occupational peritoneal mesothelioma from exposure to tremolite-free chrysotile in Quebec, Canada: A black swan case. Retrieved from https://doi.org/10.1002/ajim.20882
• Dufresne, A., Harrigan, M., Massé, S., & Bégin, R. (1995). Fibers in lung tissues of mesothelioma cases among miners and millers of the township of Asbestos, Quebec. Retrieved from https://doi.org/10.1002/ajim.4700270412