Public Health

A heavy metal that causes real damage

Every day, several hundred thousand Quebec workers are exposed to beryllium, a toxic metal that can potentially cause a pulmonary disease called berylliosis. The symptoms of this disease include a shortness of breath, coughing, chest pain and general weakness.

Between 1999 and 2002, 16 workers were recognized as suffering from chronic berylliosis by a committee set up by the Occupational Health and Safety Commission (CSST). Another 33 workers are probably affected to a lesser degree, 12 of these being recognized as having sub-clinical berylliosis and another 21 as sensitized to beryllium. Their average age is 46 years.

“Some cannot work anymore and their quality of life is diminished,” explains Joseph Zayed of Université de Montréal. “Although the disease cannot be cured, the symptoms can be treated by medication. While the disease is well known to occupational health specialists, and the first emission standards date back to 1949, the precise mechanism by which it attacks the respiratory tract is still unknown. However, a research project under the direction of Professor Zayed seeks to shed light on the microscopic dust that appears to cause the disease. The Robert Sauvé Occupational Health and Safety Research Institute (IRSST) will provide close to one million dollars in funding for the research.

Workers in industries that use beryllium are most at risk: non-ferrous foundries, aluminum smelters, welding and semi-conductor ceramics manufacturing plants, manufacturers of aeronautic parts, arms, and nuclear energy industries. The most insidious thing about its effect on the respiratory tract is that the period of exposure to the metal can be relatively short, while the symptoms appear many years later. “The symptom latency period, which means the time between the first exposure and the appearance of signs of the disease, is generally from 10 to 15 years. The disease may appear while the subject is still being exposed to beryllium, or it may not appear until 25 years after the last exposure,” according to a document put out by the Ministry of Labour.

“We are going to use animal models to test three chemical forms of beryllium, pure beryllium, beryllium oxide and beryllium copper. Our working hypothesis is that toxicity varies from one form to another,” explains the professor, who is connected to the Department of Environmental and Occupational Health in the Faculty of Medicine.

The implications of this research could be far-reaching, as international standards could be revised depending on the toxicity of the different chemical forms of the metal. “Currently,” explains Mr. Zayed, “the scientific community believes that there is not enough toxicological information and scientific knowledge on workers’ exposure to firmly establish a new standard of occupational exposure.”