What is McIntyre Powder & Why Is It Harmful?

February 14, 2022

What is McIntyre Powder & Why is it Harmful? – Chemscape

McIntyre Powder is an aluminum powder that was administered to miners in Canada and the United States between 1943 and 1979. Inhaling McIntyre Powder prior to each shift was thought to prevent silicosis among miners, but later was found to have no protective effect. McIntyre Powder exposure has been linked to a variety of neurological conditions including Parkinson’s Disease.  Workplace exposure now guarantees Workers Compensation Board benefits in Ontario. Tens of thousands of miners would have been exposed to McIntyre Powder aluminum dust during the 36 years that it was used in the workplace.

The McIntyre Powder Project 

A volunteer registry called the McIntyre Powder Project was started to document health issues (particularly neurological) in miners or other workers who were exposed to aluminum dust from McIntyre Powder. The goal is to collect information on the health issues workers exposed to McIntyre Powder are experiencing, to assist in research on long-term health impacts of aluminum dust exposure, and to seek compensation for those registered.    

When exploring a relationship between exposure to a substance and resulting illness, other exposures that may have occurred at the workplace need to be investigated (like other chemicals that are neurotoxic or make Aluminum more toxic). Family genetics or exposure to Aluminum outside of work may contribute to how and why a worker gets sick. Aluminum can also be stored in bones and then released years later, so the disease may not be identified immediately, and exposures gained over a worker’s lifetime need to be explored.  

McIntyre Powder Exposure listed as a Schedule 3 Disease in Ontario 

In Ontario, McIntyre Powder has been deemed a Schedule 3 disease which is significant for workers. Schedule 3 is a list of diseases for which the Ontario Worker Safety Insurance Board (WSIB) will pay benefits if you have the disease and you worked in a process associated with that disease. Note that eligibility of the claim may be affected by workplace exposure to a substance that was not long enough to be significant, or if other factors, such as smoking, were responsible for the disease.  

Non-mining Industries Affected by McIntyre Powder  

Other industries during this time period may have been affected as McIntyre Powder aluminum dust was also used to "treat" the employees of several non-mining industries in the United States and a few such industries in Canada. These industries included:  

  • Pottery manufacturers 
  • Foundries 
  • Silica brick manufacturers 
  • Refractories.   

During these individualized "treatment" sessions, the employee would inhale McIntyre Powder aluminum dust through a mouthpiece-hose apparatus attached to a ball mill that ground the aluminum into a very fine, respirable aluminum dust.  

McIntyre Powder Exposure  

McIntyre Powder exposure is now being considered by the Ontario WSIB as a contributing factor to Chronic Obstructive Pulmonary Disease (COPD) development. Other diseases of investigation for workers with a history of McIntyre Powder include sarcoidosis, idiopathic pulmonary fibrosis, interstitial lung disease, and cardiovascular issues as well as further work on other neurological disorders.  

McIntyre Powder serves as yet another “cautionary tale” for knowing and controlling worker exposures to toxic substances in the workplace and a plug for Total Worker Health.   

Avoid Hazards with a Total Worker Health Approach 

The Total Worker Health (TWH) approach prioritizes a hazard-free work environment for all workers. It also brings together all aspects of work in integrated interventions that collectively address worker safety, health, and well-being.  

Traditional occupational safety and health protection programs have primarily concentrated on ensuring that work is safe and that workers are protected from the harms that arise from work itself. TWH builds on this approach through the recognition that work is a social determinant of health.  

Job-related factors such as wages, work hours, workload, interactions with coworkers and supervisors, and access to paid leave impact the well-being of workers, their families, and their communities. The long-term vision of the TWH program is to protect the safety and health of workers and advance their well-being by creating safer and healthier work.

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