Horne smelter lowered arsenic levels, but locals say it’s not enough

Horne Smelter at Rouyn Noranda, 600 kilometres northwest of Montreal. (CTV W5)

The Horne smelter, owned by Glencore, announced it has lowered the annual average of arsenic it releases over the last two years, but the improvement isn’t reassuring the Mères au Front group in Rouyn-Noranda.

The concentration of arsenic emitted into the air in 2024 by the Rouyn-Noranda smelter, in Quebec’s Abitibi-Témiscamingue, would have reached an average of 39.1 nanograms (ng) per cubic metre (m3) for the year.

These results are 13 times higher than the provincial standard of 3 ng/m3, but they still reflect an improvement in air quality in Rouyn-Noranda compared with previous years.

“We’ve gone from 73 ng/m3 in 2022 to 39 this year,” said Marie-Elise Viger, environmental manager for North American copper operations, at a news conference Thursday.

“This is really the fruit of all the projects that have been put in place. We’ve installed new dust collectors, we’ve paved roads to improve collection and cleaning, and we’ve installed domes. This year, we also upgraded existing dust collectors,” explained Viger.

According to the company’s data, “over 90 per cent of the Rouyn-Noranda urban area has an arsenic concentration in the ambient air of less than or equal to 7 ng/m3 and 99 per cent less than or equal to 15 ng/m3.”

Unacceptable, according to Mères au front

The annual standard set by the Règlement sur l’assainissement de l’atmosphère is 3 nanograms (ng) per cubic metre (m3).

But over the years, the smelter has benefited from special agreements with the government.

In the most recent ministerial authorization granted by Quebec in 2023, the foundry was required to achieve a target of 45 ng/m3 in 2024 and 15 nanograms per cubic metre (ng/m) of arsenic by 2027.

But the “citizens of the city” have always “rejected this plan,” according to the Rouyn-Noranda group Mères au front.

“We find that the situation continues to be completely unacceptable because the population continues to be exposed to contaminant concentrations that are harmful to health and that outrageously exceed Quebec standards,” said Jennifer Ricard-Turcotte, co-spokesperson for Mères au front de Rouyn-Noranda.

“We believe that the government must assume its responsibility to protect the people of Rouyn-Noranda. It must also ensure that our right to live in a healthy environment is respected,” she added as she grew up near the smelter.

Arsenic emissions from the Horne smelter are associated with an estimated increased risk of cancer.

In the summer of 2022, a report by the Institut national de santé publique du Québec (INSPQ) revealed that, over a period of 70 years, an excess number of Rouyn-Noranda residents, between one and 14, would develop cancer if Glencore did not reduce the concentration of arsenic in the air produced by the smelter.

A voluntary biomonitoring program

Last February, Glencore announced the launch of a voluntary arsenic biomonitoring program for its employees, their families, friends and certain local residents.

The goal is twofold, according to Vincent Plante, general manager of Fonderie Horne, who explained a few months ago that the company wanted “to provide our employees, their families and friends living in Rouyn-Noranda with the opportunity to assess their biological exposure to arsenic, as well as to better document and understand biological exposure at community level.”

The study is due to start this month, and the individual results “will be sent to participants who consented,” while “the community results will be presented to participants and the community as a whole in April 2026.”

Public Health conducted biomonitoring studies in the Notre-Dame neighbourhood of Rouyn-Noranda, opposite the smelter, in 2018 and 2019.

The results showed that arsenic concentrations in the fingernails of residents of this neighbourhood were on average 3.7 times higher than those observed in the population of Amos, another town in the region.

This report by The Canadian Press was first published in French April 17, 2025.

Stéphane Blais, The Canadian Press