Voluntary Arsenic Biomonitoring Program

Over the past 5 years, we have repeatedly requested that a new biomonitoring study, based on a scientifically recognized methodology, be carried out to gain a better understanding of the actual exposure of the Rouyn-Noranda population.

Such a biomonitoring study is long overdue. The Horne Smelter has therefore taken the initiative of commissioning Intrinsik, a qualified third party with experience in similar biomonitoring studies, to provide the people of Rouyn-Noranda with the answers they deserve.

Our goal was to provide our Horne Smelter employees, their families and associates with an arsenic biomonitoring Program that meets the highest scientific standards and provides them with answers as the Rouyn-Noranda community seeks more information about its arsenic exposure.

The Program was launched in April 2025 and ran for 10 months. A total of 5 urine samples, 1 toenail sample and a series of soil and indoor dust samples were collected from each participant who agrees to participate, according to a specific schedule.

Ambient air was also sampled using a number of mobile stations located throughout the territory, in order to take account of the variability of arsenic concentrations in the air and to enable correlations between arsenic measured in urine and toenail samples and arsenic measured in ambient air.

Participants received a copy of their urine and/or toenail and/or soil/indoor dust results after each round of sampling, if they have consented to it. An anonymized community report was also produced by Intrinsik and presented to participants and the wider community at the end of the Program, in June 2026.

To be eligible for the Program, participants must:

• Have lived in Rouyn-Noranda for at least the past 6 months
• Be at least 9 months old

Although this Program was intended for our employees, their families and associates, any member of the community was eligible for the Program and could participate if they met the eligibility criteria mentioned above.

Please note that employees working in the smelting sector who were already subject to the Occupational Health Surveillance Program were not eligible for the Arsenic Biomonitoring Program; however, their families and associates were.

Participation in the Program was on a voluntary basis. The decision of each potential participant whether or not to participate in the Program was communicated by the participant directly to Intrinsik and was kept strictly confidential by Intrinsik, which did not share any information with the Horne Smelter.

All data collected by the Intrinsik team, including participants' identities (whether or not you have decided to participate in the Program), personal information, personal biomonitoring results and responses to questionnaires remain confidential. Intrinsik will keep this information strictly confidential and will not share it with anyone other than Intrinsik's local physician and participants' family physicians, if they have given their consent. In particular, Intrinsik will not share any of this information with the Horne Smelter.