Smelter funded study that found nearby residents are not at greater risk from arsenic

The Horne smelter, owned by Glencore, is pictured in Rouyn-Noranda on October 29, 2022. (Stéphane Blais/The Canadian Press)

The owners of the Horne Smelter in Rouyn-Noranda, Que. paid for a study that found that residents living near the facility are at no higher risk of arsenic exposure than other Canadians.

The study funded by Glencore Canada found that eating rice or seafood exposes people to higher levels of arsenic than residing near the copper smelter. The findings stand in stark contrast to previous reports by public health officials that have highlighted elevated levels of exposure and risks for the local population.

The Horne smelter announced the launch of a voluntary arsenic biomonitoring program for its employees and their families in February 2025. 

The study analyzed urine samples from 81 children and 164 adults, along with nail clippings. 

The research was carried out by Ontario-based firm Intrinsik, which presented the results of the study today.

Vice-president and chief toxicologist Elliot Sigal told media that arsenic levels among participants in Rouyn-Noranda are comparable to, or lower than, those observed in other Canadians.

“The participants’ arsenic levels were equal to or below the Canadian national average,” he said, adding that “diet was the main contributor to arsenic exposure, more so than proximity to the smelter.”

Sigal said he was not concerned by arsenic levels in the air. He added that people who want to reduce exposure to environmental contaminants can take steps such as rinsing rice thoroughly before cooking. 

Glencore Canada said in a statement that the results are reassuring “and support what the Horne smelter has always believed: its facilities are safe for the public,” said Vincent Plante, executive general manager for the company’s North American copper division.

Public health authorities have not reached the same conclusions in recent years.

In the summer of 2022, a report by Quebec’s public health institute, the Institut national de santé publique du Québec, revealed that, over a 70-year period, an excess number of residents in Rouyn-Noranda — between 1 and 14 — would develop cancer if Glencore did not reduce the concentration of arsenic in the air emitted by the smelter. 

In 2022, arsenic emissions from the smelter stood at 73 nanograms per cubic meter. The average concentration of arsenic in the air in 2025, as measured by the smelter, decreased to 40.9 ng/m³, according to data recorded at the Horne monitoring station in the Notre-Dame neighbourhood. 

Despite the improvements, arsenic emissions in 2025 remained 13.6 times higher than the provincial standard. 

In the fall of 2019, the regional health authority for Abitibi-Témiscamingue conducted a biomonitoring study which found that arsenic concentrations in the fingernails of residents in the Notre-Dame neighbourhood were “on average four times higher than those observed in the control population in Amos, which is not exposed to industrial sources of arsenic.”

Among participants in the Notre-Dame neighbourhood, “those living closer to the Horne smelter generally have higher concentrations of arsenic in their fingernails” and “nail arsenic concentrations are significantly higher in children than in adults,” according to the 2019 study.

The Abitibi-Témiscamingue public health department did not immediately respond to the results of Glencore’s study.

This report by The Canadian Press was first published June 9, 2026.

Stéphane Blais, The Canadian Press