Ontario health agency finds 'concerning' rate of ALS in miners exposed to McIntyre Powder

Occupational Health Clinics for Ontario Workers says it's found a high incidence rate of ALS in miners exposed to an aluminum dust once thought to protect their lungs. The anecdotal findings have caught the attention of scientists who plan to see if there's a scientific link.

For decades, miners were encouraged to inhale the fine aluminum dust to protect their lungs

Dave Wilkin of Occupational Health Clinics for Ontario Workers shows The Fifth Estate's Gillian Findlay body maps of miners exposed to McIntyre Powder. (CBC)

An Ontario health agency says it's found a "concerning" rate of ALS in miners exposed to an aluminum dust once thought to protect their lungs, The Fifth Estate has learned.

There is no proven scientific or medical link between neurological disorders and McIntyre Powder, but mounting anecdotal evidence has motivated some scientists and doctors to take another look. 

"There is good reason to investigate the hypothesis that this type of exposure can cause a range of neurological disorders," said Dave Wilkin of Occupational Health Clinics for Ontario Workers (OHCOW), a publicly funded organization that deals with workplace and work-related health issues.

Two years ago, Wilkin and his team at OHCOW teamed up with Janice Martell, whose father was exposed to McIntyre Powder while working in nickel and uranium mines in northern Ontario between 1959 and 1990 and was diagnosed with Parkinson's in 2001.

They host intake clinics for miners from across the country who inhaled the powder on the job. They map and study detailed health histories of the miners, collate the data and examine their findings.

From The Fifth Estate's 'Powder Keg' episode in 1979: Before shifts, change rooms in mines were filled with McIntyre Powder, which workers were encouraged to breathe in as deeply as possible. (CBC)

They say they've found a "concerning" number of former miners exposed to McIntyre Powder who now have ALS — seven cases of ALS in a group of just over 300 miners.

"This number jumps out at you," Wilkin said. "This might be telling us something. This is a very rare and a very serious condition."

Amytrophic Lateral Sclerosis or Lou Gehrig's disease is rare in the general population — occurring at a rate of two cases per 100,000 people. The degenerative disease causes paralysis and eventually death as the brain gradually loses its ability to communicate with the body's muscles.

McIntyre Powder, developed at McIntyre Mine near Timmins, Ont., is a finely ground aluminum dust that company officials said would protect miners' lungs if inhaled at the start of every shift.

McIntyre Powder was thought to prevent silicosis in miners and was to be inhaled before shifts. (CBC)

Many miners were forced to use it as a condition of employment between the years of 1943 and 1979 in mines around the world.

The product had only been tested on a small number of rabbits and guinea pigs before it was put on the market and provided to tens of thousands of miners. 

In March, Martell and Wilkin presented their findings to an audience in Vancouver featuring some of the top international scientists who study aluminum. Martell's appeal struck a chord, and scientists at McMaster University in Hamilton, Ont., will soon start further study on the miners she's identified over the past two years.

McIntyre Powder Project

It was only after Martell's father, Jim, was diagnosed with Parkinson's disease that she learned about McIntyre Powder and started wondering if there could be a link.

When she filed a claim with Ontario's Workplace Safety and Insurance Board (WSIB) for her father five years ago, the answer was unequivocal: No established link exists.

That's when Martell went to work, scouring government archives for anything she could learn about the powder and reaching out to miners of her father's generation, asking if they'd been exposed and whether they were sick.

Janice Martell, founder of the McIntyre Powder Project, is pushing for scientific study of a possible link between the powder and neurological disorders. (CBC)

"I was blown away," Martell told The Fifth Estate in 2016. "Silicosis is a disease of the lung produced by inhaling dust. So they're going to ... fight it by inhaling another kind of dust. I can't imagine grinding up a piece of tinfoil and inhaling that and then thinking that would be good for you."

Martell has spent the past two years attempting to find help for these miners through her McIntyre Powder Project, and trying to prove the anecdotal evidence she's found has a basis in science — that the McIntyre Powder did, indeed, cause disease, and that miners who were exposed should therefore be compensated.

When The Fifth Estate spoke to Martell last winter, she had a list of 135 people who claim they've suffered long-term neurological health problems and were given McIntyre Powder.

Martell has been encouraging former miners who may have been exposed to McIntyre Powder to attend information clinics. (Facebook/McIntyre Powder Project)

Today, Martell's list has 363 names.

She continues to search for more miners like her father. She hosts clinics across northern Ontario and has heard from miners from as far away as B.C. and the Maritimes.


Lisa Mayor


Lisa Mayor is a journalist with CBC News on Prince Edward Island. Before arriving on the Island, she worked in Toronto as an investigative journalist with CBC's The Fifth Estate, where she received three Canadian Screen Awards, a Michener Award and a National Radio Television Digital News Association Award. She can be reached at