Superior Court authorizes class action lawsuit against Horne smelter and Quebec

MONTRÉAL – A Quebec Superior Court judge has authorized a class-action lawsuit on behalf of citizens who claim to have been affected by emissions from Glencore’s Horne smelter in Rouyn-Noranda, Que.

In a 50-page decision released Wednesday, Superior Court Judge Daniel Dumais authorized the lawsuit against the copper smelter and the Quebec government.

The plaintiffs had wanted to claim damages dating back to 1991, but the judge limited that to 2020 due to a statute of limitations.

The Swiss-owned smelter has come under fire in recent years for arsenic emissions that Quebec had allowed to be 33 times the provincewide standard. 

In 2022, the province said it would permit the smelter to emit arsenic levels five times the norm, but the company had only succeeded in getting its annual average down to 15 times the standard in 2023.

Justice Daniel Dumais wrote in his decision that the plaintiffs’ claims of damage were based on abundant evidence of contaminants that exceed the norm.

He also noted a 2022 report by Quebec’s public health institute that indicated that past and current exposure to arsenic and cadmium concentrations from the smelter could put residents at a higher risk of cancer.

The allegations contained in the lawsuit have not been tested in court. 

A spokesperson for Glencore Canada said the company would not comment on matters before the court. 

However, Fabrice de Dongo added that “we are confident that the Horne smelter’s operations are safe for the population. They were safe 20 years ago when arsenic concentrations in the air were much higher, and they are safe today when approximately 99 per cent of the urban area of Rouyn-Noranda has 15 ng/m³ or less of arsenic in the ambient air (annual average).”

The class action also targets the Quebec government over “the inadequacy of government and ministerial actions since 1979 and of the remediation authorizations issued since 2007,” according to Dumais’ summary of the plaintiffs’ position.

The decision notes that the plaintiffs are critical of the government for knowingly allowing companies to exceed the provincial standards for emissions, which they believe constitutes an “unlawful violation of the fundamental rights of members to live in a healthy environment that respects their safety, integrity, and right to enjoy and freely dispose of their property.” 

The plaintiffs are divided into two subgroups, the first consisting of individuals who reside or have resided in Rouyn-Noranda within 10 km of the Horne smelter since October 23, 2020 “and who have suffered or continue to suffer fear, anxiety, stress, anger, guilt, or any other similar damage as a result of toxic and/or carcinogenic emissions from the Horne smelter.”

The second group includes those who also live or have lived within the same radius during the same period “and who have suffered or continue to suffer financial loss and/or disturbances and inconveniences due to toxic and/or carcinogenic emissions from the Horne smelter.”

The plaintiffs are claiming damages that could reach or exceed $315,000 for each member of the class action.

This report by The Canadian Press was first published Oct. 2, 2025.