The air deep in an underground mine hangs thick with heat and exhaust. Diesel from machines sits heavy in the air while dust from exploded rock covers every surface long after the drilling stops and the blast settles.
The deeper you go, the worse it gets. Temperatures climb to 30 C. Humidity and sweat soak through clothes, even when you’re standing still.
Silica dust generated from blasted rock and ore stings the eyes and clings to the throat and lungs.
Ron Rousseau spent more than four decades breathing it all in.
For 41 years, Rousseau worked in uranium, gold and nickel mines across northern Ontario — drilling, blasting and hauling rock, building new underground levels, using diesel-operated machines to drill, often more than 8,000 feet below the surface.
The work was relentless, Rousseau said. He worked 10-hour shifts, sometimes getting home at 5 a.m.
“Down there, you’re fighting with every element you can think of,” he said. The dust is inescapable and the ventilation “is never good enough.”
In 2024, at age 64, Rousseau was diagnosed with stage four lung cancer. Doctors told him the tumour was the size of a mandarin and gave him two years to live.
He has stopped working and is undergoing treatment for the illness, which the Workplace Safety and Insurance Board confirmed was tied to his job. But his loss-of-earnings benefits are set to be cut off when he turns 66 this summer, leaving him in a difficult financial position and weighing whether he should return to the mines to support himself and his wife.
As Canada moves to fast-track mining projects across the country to fuel economic growth, industry observers warn the push is outpacing worker protections.
Miners already face elevated risks of cancer and chronic illness from exposure to carcinogens such as diesel exhaust and silica dust. Expanding the industry at an accelerated rate without stronger oversight and legislation could deepen those harms, industry observers and medical experts say.
Between 1990 and 2023, 792 lung cancer claims related to mining were filed with Ontario’s Workplace Safety and Insurance Board, according to freedom-of-information data provided to the Star by the United Steelworkers Local 6500. The union represents more than 2,600 workers at Vale Base Metals’ Sudbury operations — one of the largest integrated mining complexes in the world.
Diesel engine exhaust exposure affects about 301,000 workers in Ontario, nearly five per cent of the province’s workforce, and is linked to an estimated 170 lung cancer cases each year, according to a report from the Occupational Cancer Research Centre. The burden is highest in the mining industry, which accounts for 40 per cent of those lung cancer cases, followed by transportation and warehousing at 23 per cent.
Canada is a major producer of critical minerals such as nickel, copper and cobalt, essential to electric vehicles, batteries and clean energy technologies. Officials say expanding mining could draw billions in investment and create thousands of jobs.
Ontario’s 36 active mines produced $15.7 billion worth of minerals and metals in 2023, up 50 per cent from 2013, according to the Ontario Mining Association.
In March, Ontario Energy and Mines Minister Stephen Lecce said the province is “unapologetically advancing a bold agenda” to accelerate approvals, improve regulatory certainty, invest in domestic processing and advance major projects like the Ring of Fire — an area in northern Ontario rich with critical minerals — projecting up to $22 billion in added GDP and 70,000 jobs in the mining sector over the next 30 years.
But medical experts and labour advocates warn that the workers must not be left out.
“Miners face such an elevated risk already — without proper oversight and improvements to safety measures, I think we would see higher rates of cancer,” said oncologist Dr. David Boyce, who is also a medical consultant for the Occupational Health Clinics for Ontario Workers. He noted outdated exposure limits, and a workers compensation system that often fails to recognize occupational disease.
Current oversight is “lacking and needs to be improved as we’re making this push further into mining.”
The illnesses linked to mining
Mining is widely considered hazardous and physically demanding work.
In Ontario’s mines, the greatest threat isn’t injury but often illnesses that develop slowly, surfacing years and even decades after the workers have left the job.
Provincial data shows that the vast majority of mining deaths are caused by disease. Occupational illnesses account for 87 per cent of all fatalities in Ontario’s mining sector, according to the Ministry of Labour.
Miners spend years breathing in a toxic mixture of lung carcinogens — particularly diesel exhaust and fine silica dust — strongly linked to lung cancer and other respiratory diseases including chronic obstructive pulmonary disease (COPD), silicosis and pulmonary fibrosis.
Silica is one of the most common minerals on earth, embedded in the rock miners drill and blast every day. When that rock is cut or shattered, it releases particles small enough to be inhaled deep into the lungs and to affect other organs. This respirable silica is present at almost every stage of the mining and refining process.
Ontario mine workers show a 54 per cent higher incidence of lung cancer than provincial averages and 165 per cent higher COPD incidence rates than the general population in the province, according to data from the Occupational Cancer Research Centre.
The true tolls of illness and deaths are likely far higher.
“These are long-latency diseases,” Boyce said, thus much harder to track. “We’re seeing cancers now that are likely from exposures two decades ago.”
By the time symptoms appear many miners have left the industry; their illnesses are often unreported and not formally linked to their work.
“We’re likely missing a lot of cancers in miners who are not even identifying it because they might be retired,” Boyce said.
The United Steelworkers Local 6500 reports that 47 occupational disease deaths among its members have been recognized by the WSIB.
Data obtained through freedom-of-information requests shows that of the 792 claims made for lung cancer from mining from 1990 to 2023 in Ontario, 266 came from employees of Vale, one of the largest mining employers in the province. The WSIB approved only 398 claims in total.
During that time, 391 COPD claims and 207 silicosis claims were filed, with 53 per cent of COPD cases and 73 per cent of silicosis cases approved by the WSIB.
“Our operations adhere to or exceed regulatory requirements and safety standards,” said an emailed statement from Vale Base Metals Ltd.
The company said it has invested more than $1 billion in “environmental upgrades at our operations in Sudbury to reduce emissions” and is using “cleaner technology like electric vehicles, advanced ventilation systems with robust monitoring, voluntary testing for exposure, and automation that removes people from high-risk tasks, all of which protect workers before potential dangers can cause harm.”
But these WSIB numbers are only the tip of the iceberg, said Sean Staddon, a compensation officer at USW Local 6500 who helps workers file WSIB claims. Many more claims are still being processed or appealed, he said.
Staddon added that the issue is industry-wide, not limited to any single company, noting that Vale is simply one of the largest mining operators in Ontario.
A 2016 Star investigation found that the overwhelming majority of appeals from workers whose benefits were reduced due to so-called pre-existing conditions have been overturned by the WSIB’s independent appeals tribunal since 2012. But because of backlogs, it can take years for workers and their families to receive the benefits they were owed.
Staddon says he is currently handling more than two dozen additional cases under appeal. Based on what he sees, Staddon estimates roughly two members die each month from occupational diseases linked to their work, many of those deaths going unreported.
For many families, claims are approved long after their loved one has died.
‘Antidote’ to lung disease was anything but
It took the WSIB until 2024 to approve the claim of Cindy Abramson’s father— eight years after his death, and nearly a decade after he was diagnosed with stage four lung cancer.
Jim Abramson had worked in northern Ontario mines for more than 30 years before retiring in 1996. He was diagnosed in 2015. Within a year, he was gone.
Jim was one of 27,000 gold and uranium miners in northern Ontario who were routinely sealed in a room before their shift and forced to inhale an aluminum-based prophylaxis called McIntyre Powder, between 1943 and roughly 1980. It was sold as a miracle antidote to lung disease. Historical documents suggest it was created by industry-sponsored Canadian scientists bent on slashing compensation costs in gold and uranium mines across the north, with no testing for potential harms to humans.
The Occupational Cancer Research Centre found that miners exposed to the powder had a 34 per cent greater incidence rate of Parkinson’s disease. The powder has also been linked the development of lung disease.
Jim inhaled the powder for nearly two decades. Still, his claim was initially denied, and it took 10 years for his family to have the decision overturned.
Jim’s “occupational exposures to silica, diesel exhaust and radon significantly contributed to his condition of lung cancer,” reads the WSIB decision letter, dated February 2024, seen by the Star.
Without an autopsy confirming that her father died of lung cancer, “I truly don’t feel we would have won the case,” Cindy said. “We had pretty much given up on having a positive outcome.”
Do Ontario’s exposure limits protect miners?
For many workers like Jim Abramson and Ron Rousseau, the issue is not only compensation but whether Ontario still permits dangerous levels of exposure to carcinogens underground that contribute to illness.
A major concern is that Ontario’s occupational exposure limits — the legal thresholds for hazardous substances like diesel and silica in the workplace — remain far above what health experts deem safe.
Until recently, Ontario had the highest diesel exposure limits for underground workers in the country, at 400 micrograms per cubic metre. In 2023, the Labour Ministry announced those limits would be reduced to 120 micrograms per cubic metre, significantly higher than several countries in Europe and in Australia. The Occupational Cancer Research Centre recommends a safe limit of 20 micrograms per cubic metre.
In Ontario, the legal exposure limit for silica, considered one of the most significant airborne hazards faced by miners, is four times the level recommended by the American Conference of Governmental Industrial Hygienists.
“To address long-term occupational illness, we are taking concrete steps to improve prevention, detection and response,” the Labour Ministry said in an email, pointing to the launch of an occupational exposure registry designed to track worker exposures over time and support earlier intervention.
The ministry did not directly answer questions about whether Ontario will revise its exposure limits, or how it will ensure that fast-tracking projects does not compromise worker health and safety protections.
Ontario’s Ministry of Energy and Mines did not respond to questions about how it will ensure worker health and safety is maintained as mining projects are fast-tracked, or how it is addressing risks and holding mining companies accountable to existing safety standards.
‘Mike’s life was worth more than that”
For workers who develop illnesses, navigating Ontario’s workers compensation system can mean the start of another battle. Staddon said delays are common and claims often take a year or two to process, and even longer if they are denied and appealed.
In some cases, they take much longer. Staddon recalled one claim that took more than two decades to be approved.
Like Jim Abramson, workers often die before seeing the outcome, leaving spouses and family members to carry on fighting, for survivor benefits, through the WSIB.
Celine Quenneville’s husband, after nearly four decades working in northern Ontario mines, was diagnosed with stage four lung cancer in January 2023. The disease had already spread to his brain, where doctors found three tumours.
Four months later, Michael Quenneville died.
“It happened so fast,” Celine said.
After his death, she filed a claim with the WSIB. It took more than a year to receive a one-time payout of about $28,000. That was based on a 56 per cent work-related permanent impairment rating — a key figure in determining how much compensation workers receive from the WSIB.
The amount, Celine said, was a “slap in the face.”
“Mike’s life was worth more than that.”
According to a WSIB report obtained by the Star, Michael’s lung cancer was assessed as a 100 per cent impairment. But his prior work-related injuries, already paid out and totalling 44 per cent, reduced his remaining eligible impairment rating to 56 per cent.
Celine is in the process of appealing the decision. She promised her husband she would continue the fight for both current and future generations of miners.
“Mike wasn’t ready to die. He had just turned 58,” she said. “We should have been able to retire together. That was taken away from us.”
The WSIB said it works “as quickly and thoroughly as possible” when reviewing occupational disease claims, but acknowledged that cases can take longer when medical and workplace records span decades.
The government agency said it considers “the best scientific evidence available” and reviews workplace exposures, including multiple and cumulative exposures over a worker’s career, with assessments conducted by occupational hygienists.
Will fast-tracking mining projects affect risk assessment?
Without the proper oversight, risks and carcinogen exposure are likely to increase as governments move to accelerate mining development, health experts say.
“The only way to fast-track projects is often to minimize the oversight,” said Paul Demers, director of the Occupational Cancer Research Centre.
That can mean less consultation, less research and fewer opportunities to identify and address risks before a mine begins operating, he said.
Ontario’s Bill 5, enacted last year, allows the province to designate so-called “special economic zones,” areas where it can suspend any and all laws in order to construct large projects, including mines.
Compressed timelines could influence how mines are set up, Boyce said.
Companies may choose diesel-powered equipment over electric alternatives because it is cheaper and faster to deploy. Ventilation systems may be built to meet minimum regulatory requirements, rather than anticipating future needs or stricter standards for the sake of speed.
Amid the rapid expansion, the industry is increasingly relying on contract workers who move from worksite to worksite, Staddon said, making it harder to track long-term exposure histories and hold companies accountable.
While the mining industry creates jobs and contributes to the economy, Staddon said Ontario “cannot claim economic independence while accepting occupational disease as collateral damage.”
“Critical minerals cannot be built on expendable lungs.”
For Cindy Abramson, her father’s death is a warning about the cost of unregulated workplace practices.
“I believe (his illness) was preventable,” she said. “Companies shouldn’t be in charge. We need policies to ensure the protection of workers.”
