What exactly is in McIntyre Powder? Sudbury researcher analysing dust inhaled by miners

New research is underway in Greater Sudbury into what exactly miners breathed into their lungs when they inhaled McIntyre Powder.

Hundreds of miners reporting health issues after breathing in powder, thought at the time to be protective

There are four known canisters of McIntyre Powder that were used between 1943 and the 1980s. The white can pictured here is the original canister. The canister on the far right states: "For silicosis therapy. For use only under doctors direction." (Supplied/Janice Martell)

New research is underway in Greater Sudbury into what exactly miners breathed into their lungs when they inhaled McIntyre Powder.

Between 1943 and the 1980s, the aluminum dust was used in mining operations all over the world, including in northern Ontario. In fact, the substance was created at the McIntyre mine in Timmins.

Miners were told by their employers they had to breathe in the powder before their shifts underground as a way to protect their lungs.

Many of those workers now report that they have developed respiratory and neurological illnesses — and others have died from those illnesses or complications arising from them.

Still, a clear and proven connection between the powder and the illnesses the miners developed has not been established.  

Janice Martell of Sudbury created the McIntyre Powder Project four years ago to help collect data that would prove the powder was dangerous to the miners who breathed it in.

Janice Martell has been working on the McIntyre Powder Project for four years. Her late father developed Parkinson's Disease. Martell believes it was from the years he inhaled McIntyre Powder as a miner in Elliot Lake. (Angela Gemmill/CBC)

Part of the project includes a registry of workers exposed to the powder — and currently, there are 479 on the list.

There is provincial research commissioned by the Workplace Safety Insurance Board (WSIB) going on to determine if there is a link between the powder and the health issues.

But now, Martell said another scientist is looking into the McIntyre Powder itself.

There are four known types of canisters of the powder that were used over the four decades.

Some of the powder has been described as charcoal black, while other is grayish-white in colour.

"Most of my miners talk about it being a black fog and a black dust cloud that came out of the compressed air system in the mine change rooms," Martell said.

Several canisters of the powder have been acquired by Martell and the Occupational Health Clinics for Ontario Workers (OHCOW).

Those canisters have been passed on to PhD researcher Andrew Zarnke at Laurentian University in Sudbury who is analyzing them all.

The research will put powders under a microscope to see what exactly they're made of, whether there were contaminants in them, how big the powder particles are, and how the body reacts to the powders.

"Then we're left with the question of which guys got which canisters over time," Martell said.

"If you worked in a mine for 20 years were you exposed to four different types of McIntyre Powder?"

"We don't know. None of them know."

Records have shown 27,500 workers in Ontario inhaled McIntyre Powder during the four decades it was used in mines in this province.

"I want to know, did this aluminum dust do harm? I want to know that. I want to know that as a daughter of a mine worker who got Parkinsons," Martell said.

"Our mine workers and our mining families deserve those answers."

'They were not give the choice'

Martell recalls hearing stories of miners who watched their fathers and grandfathers die of silicosis, a condition caused by inhaling silica over time.

She said when these younger miners were told that the aluminum powder would save them from this fate, they would put the nozzles up to their mouths and inhale as much as they could.

She calls McIntyre Powder a human experiment and a violation of human rights, arguing there was no scientific proof that it ever worked, and the miners were forced to breathe it in— or they weren't allowed to work.

"They were exposed to this as a human experiment. They were not given the choice."


Martell wants compensation for all the workers who were exposed to McIntyre Powder, and wants to connect with a law firm to begin a class-action lawsuit. It would also include the families of affected miners who have died.

"These mine workers who were exposed deserve compensation ... from the government bodies who were supposed to have regulatory oversight and protect these workers and who abdicated that responsibility, and from the employers who were part of it," Martell said.

For her part, she said doesn't care if she sees any money.

"It's not going to bring my Dad back. It's not going to change the miners' lives that we've lost," she said.

"But I have found that until it costs the employer more to ignore health and safety, and until it costs the WSIB more to continue in their patterns of behaviour, nothing is going to change."

Hear the interview here:


Angela Gemmill


Angela Gemmill is a CBC journalist who has covered news in Sudbury, Ont., for 15 years. Connect with her on Twitter @AngelaGemmill. Send story ideas to