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The natural occurrence of radon in homes

The Canadian Nuclear Safety Commission (CNSC) recognizes that elevated levels of radon in the environment can be concerning. Although the CNSC does not regulate mine waste rock at non-licensed sites or radon in homes, it is important for us to provide accurate, scientific information to the public about this issue and details about where additional information and guidance can be found.

Our mandate is to regulate (issue licences and ensure compliance with regulatory requirements) the use of nuclear energy and materials to protect health, safety, security and the environment; to implement Canada’s international commitments on the peaceful use of nuclear energy; and to disseminate objective scientific, technical and regulatory information to the public.

Anything we regulate under our mandate is our highest priority. Our focus will always be on protecting the health, safety and security of people, protecting our environment, and ensuring that the science and information behind our regulation is transparent and available to the public.

There is a significant history of uranium mining in Elliot Lake, as the area is naturally high in uranium. In the 1970s, the Federal–Provincial Task Force on Radioactivity (FPTFR) noted high radon levels in a number of houses. The FPTFR’s report concluded that this could have been from natural radon emanating from bedrock or from the use of mine waste rock for construction purposes. In addition, the FPTFR ensured that sufficient measures were put in place at the time to protect human health.

Take Action on Radon is a national initiative, funded by Health Canada, to bring together radon stakeholders and raise awareness about radon across Canada.

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CNSC’s role

The CNSC does not regulate naturally occurring radioactive material, such as mine waste rock at non‑licensed sites or radon in homes, as this falls outside the CNSC’s mandate.

What is waste rock?

Waste rock is simply rock that must be excavated in order to access ore, and it can be made at any mine, not just uranium mines. Waste rock from the Elliot Lake mines is naturally radioactive, as is all rock due to the decaying of minute quantities of radionuclides. Because the CNSC does not regulate naturally occurring radioactive material, a CNSC licence is not needed to possess waste rock.

Tailings and waste rock are very different materials. Tailings are the wastes produced when ore extracted from any mine is processed. Tailings are regulated by the CNSC, and a CNSC licence is required for managing tailings. When uranium ore is processed, the remaining radioactive substances in the ore are concentrated into tailings, which must be managed because they pose a hazard. The tailings management facilities at the former Elliot Lake uranium mine sites contain all of the tailings from the uranium mines. They are regulated facilities, so CNSC inspectors and experts make sure that they are operated safely. No tailings from the Elliot Lake mine sites were used as construction material for any of the homes in Elliot Lake.

How is this different from the legacy contamination in Port Hope, Ontario 

The waste rock in Elliot Lake is different from the legacy contamination in Port Hope, Ontario. In Port Hope, the community became contaminated with processed nuclear substances resulting from historic radium production, which used uranium ore from far-away mines as an input. While the CNSC did not see any health effects from the presence of this legacy waste, the Port Hope community and Natural Resources Canada chose to further remediate under the Port Hope Area Initiative, now taking place. The CNSC licences for the Port Hope Area Initiative are necessary because not excavating and consolidating this legacy waste poses hazards to people and the environment. 

What can homeowners do?

Through contracts signed between the mid-1970s and late 1990s with Atomic Energy of Canada Limited, homeowners agreed to be responsible for the long-term care and maintenance of the radon mitigation measures. For example, almost all of the homes that had radon abatement measures implemented had a radon fan installed to continuously pull air from the soil and vent it outdoors through a pipe ending above the edge of the roof.

Because radon in homes can be a hazard, Health Canada’s Radiation Protection Bureau runs the National Radon Program, which provides guidance on testing and managing radon levels in homes. The CNSC recommends that Canadians follow this guidance and take any necessary measures, such as radon testing, to ensure safe indoor air.

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