OHCOW Researchers Make Valuable Contributions to Study of Occupational Illness Caused by McIntyre Powder

McIntyre Powder (MP) was administered to miners for decades in Ontario mines in the belief that it prevented silicosis. OHCOW researchers have helped determine the harmful and life-long damage to miners’ health caused by preventable exposure to the substance.

The latest paper, “McIntyre Powder and its potential contributions to cardiovascular disease risk: A literature review through the McIntyre Powder historical lens,” appears in the American Journal of Industrial Medicine.Published in June of 2022, the study was published by Andrew M. Zarnke, BSc., an Occupational Hygienist at OHCOW, Sudbury; and Christine Oliver, MD, a medical consultant to OHCOW and an Adjunct Professor at the University of Toronto in the Division of Occupational and Environmental Health.

In this research Zarnke and Oliver continue their study of the period from 1943 to 1979, when mine workers in Ontario (as well as other locations throughout Canada and worldwide) were exposed to the powder in their workplace, often in high concentrations. The degree of fineness of the powder, along with its high concentration when used in the mines, resulted in a respirable dust that increased the lung dust burden of workers, causing lung disease over time. For ten minutes before every work shift, the powder was administered to miners.

Previous research by the team showed that the high airborne concentration that miners were exposed to caused lung damage, in combination with the respirable dust they breathed as they worked in the mines. Their recent study shows that, combined with the air pollution particulates already present in the environment, miners were also put at increased risk of cardiovascular disease (CVD).

Oliver and Zarnke have been studying occupational illness in miners for years. They previously wrote and co-wrote papers on sarcoidosis, an inflammatory lung disease. These papers are “Sarcoidosis: An Occupational Disease?”, published in 2021, and “Sarcoidosis in Northern Ontario hard-rock miners: A case series” published in the American Journal of Industrial Medicine in February 2022.

The research helped make the case for a strong causal association between occupational  exposure to MP and lung disease, damage to the immune system, and gene-exposure interactions.

OHCOW research has significantly contributed to the medical literature that has forced insurance granting organizations, such as the WSIB in Ontario, to reconsider their previous denials of compensation for miners exposed to MP. Its impact has been felt as well in other regions where the substance was used. The research is not over, as more connections are being found between exposure to MP and neurological damage in miners.