Rice increases arsenic exposure at the Horne Smelter

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

Eating rice or seafood exposes residents of Rouyn-Noranda to higher levels of arsenic than emissions from the Horne smelter, according to a biomonitoring study funded by Glencore Canada, the smelter’s owner.

A biomonitoring study conducted by the Ontario-based firm Intrinsik Corp. concludes that arsenic levels among participants in Rouyn-Noranda are “comparable to or lower than those observed in other Canadians.”

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

Urine samples from 81 children and 164 adults were analyzed, along with nail clippings.

On Tuesday morning, Intrinsik’s vice president and lead toxicologist, Elliot Sigal, presented the results of the study commissioned and funded by Glencore during a technical briefing for the media.

“The participants’ arsenic levels were equal to or below the Canadian national average,” and “diet was the main contributor to arsenic exposure, more so than proximity to the smelter,” Mr. Sigal stated.

“We are not concerned about arsenic levels in the air in Rouyn-Noranda, and there are steps people can take to reduce exposure to environmental contaminants, including being mindful of how rice is prepared and rinsing the rice thoroughly before cooking,” explained Elliot Sigal.

“So, in your opinion, eating rice is more likely to expose a person to arsenic than living next to a smelter that emits arsenic levels 13.6 times higher than the provincial standard?” asked The Canadian Press of the vice president of the firm paid by Glencore.

“What our study shows is that diet causes greater exposure than the smelter, and the form of arsenic in rice is the same form that a smelter would release,” added Elliot Sigal.

Higher risk of developing cancer

The study paid for and commissioned by Glencore stands in stark contrast to the information provided in recent years by public health authorities.

In the summer of 2022, a report by the Institut national de santé publique du Québec (INSPQ) revealed that, over a 70-year period, an excess number of residents of 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 (ng) per cubic meter (m³). 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 neighborhood.

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

At the time of writing on Monday morning, the Abitibi-Témiscamingue public health department had not responded to the study’s findings.

Stéphane Blais, The Canadian Press

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