An excessive risk of cancer in Rouyn-Noranda, even with the introduction of the standard |  Arsen Rouyn-Noranda

An excessive risk of cancer in Rouyn-Noranda, even with the introduction of the standard | Arsen Rouyn-Noranda

A calculation carried out by Radio-Canada using public health experts shows that even when standards are met, the risk of lung cancer is at least 50 times higher than the risk considered negligible in Quebec, i.e. one extra cancer case per million people who die are exposed during their lifetime.

Maryse Bouchard, a professor at the University of Montreal’s School of Public Health, explains that the Horne Foundry’s situation is quite unique, there aren’t many cases like this one in Quebec and Canada where a variety of pollutants are emitted.

“It’s a scenario that wasn’t really foreseen when the standards were developed, that people would be exposed to not one but multiple carcinogenic pollutants at the maximum allowable concentration at the same time. »

— A quote from Maryse Bouchard, professor at the School of Public Health at the University of Montreal

Two chimneys rise into the sky.

The north of the Notre-Dame district is 100 meters from the Horne Foundry.

Photo: Radio Canada / Thomas Gerbet

The Horne Foundry is the largest emitter of arsenic (36 tons last year), nickel (10 tons) and cadmium (811 kg) in Quebec. These are three known carcinogens that increase the risk of lung cancer.

Quebec sets an emission standard for each of them. The best known is that of three nanograms of arsenic per cubic meter of air (ng/m3). Each of these standards is associated with a risk factor.


Like other agencies around the world, Health Canada assesses the excess unit risk coefficient of cancer (New Window) from inhalation of an airborne pollutant. We multiplied each risk coefficient by the Quebec standard for arsenic, cadmium, and nickel. Then we added those results.

This calculation, which gives 52 additional cancer cases per million, is very conservative because it does not take into account the risk factors for ingestion and inhalation of dust on the ground. In addition, it does not contain fine particles, which are also recognized lung carcinogens but for which Health Canada does not have a risk coefficient.

The data shows that the excessive number of cancer cases directly attributable to overexposure to metals (arsenic, nickel, cadmium) is well above what is considered acceptable, observes Maryse Bouchard.

In addition, on July 6th in Rouyn-Noranda, the National Institute for Public Health (INSPQ) hypothesized that mixtures of substances could have multiplicative and not just additive effects.

On Tuesday, neither the Quebec Ministry of Health and Welfare, nor the CISSS de l’Abitibi-Témiscamingue, nor the INSPQ answered our questions on the subject.

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On Monday, the Rouyn-Noranda Municipal Council unanimously passed a resolution to demand that Quebec require the Horne Foundry to comply with Quebec standards for all heavy metals and fine particles released into the air. This has been a repeated request from citizens for several weeks.

Over the past year, the average arsenic concentration at the monitoring station closest to the facility was 87 ng/m3, a far cry from the standard of 3 that we used in our calculation.

At the moment, the foundry benefits from an exemption that allows it to emit an average of 100ng/m3 per year, or 33 times the standard. For all other metals that it emits into the air, the company is not subject to any standards.

Luc Boileau will reveal the cap he recommends

According to our information, on Wednesday the national director of health will announce his recommendation for a five-year target for Horne Foundry. The upper limit that Luc Boileau will propose will be between the standard of 3 ng/m3 and the 20 ng/m3 that the company says it can achieve within its technological and financial capabilities.

However, an annual target of 20 ng/m3 would not guarantee that there would be no impact on neurodevelopment in children (new window). This would require setting the bar at 15 ng/m3 or less.

A daily limit

As mentioned last month, the Quebec government is also considering imposing a daily emissions cap on the foundry. Because the annual standard is an average, the number can hide significant fluctuations. For example, arsenic emissions sometimes reached more than 1000 ng/m3 on certain days, Le Devoir revealed. For his recommendation, Luc Boileau can be inspired by what is being done in Ontario and New Brunswick with a standard of 300 ng/m3 over 24 hours.

Despite the press conference by Dr. Boileau at 2:00 p.m., the Quebec Ministry of the Environment will have the final say on the target to be imposed. Minister Benoit Charette must also announce his position next week, after which public consultations will take place.

On Wednesday, the INSPQ must also present an addendum to its study on the risks associated with heavy metals in Rouyn-Noranda. After publishing a report last month on the increased risk of lung cancer, public health researchers have examined the link between heavy metals and the risk of chronic obstructive pulmonary disease, growth retardation in the womb and low birth weight babies.