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CNSC response to Canadian Environmental Law Association re: Mine Waste at Four Elliot Lake Homes

June 20, 2023

Ms. Kerrie Blaise
Canadian Environmental Law Association
1500 -45 University Ave
Toronto, On
M5J 2H7

ccm general

Subject: RE: Mine Waste at Four Elliot Lake Homes

Ms. Blaise,

With reference to your letter of June 13, 2023, I can confirm that the CNSC is aware of the concerns of some members of the public regarding the disposition of mine waste rock in Elliot Lake, Ontario.[...]

The work done by the Federal-Provincial Task Force on Radioactivity (FPTFR) in the 1970s indicated high radon levels in a number of houses. The 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 either case, all the rock is naturally radioactive and would not be considered radioactive waste by the CNSC. In addition, the FPTFR ensured that sufficient measures were put in place at the time to protect human health. Via signed contracts with Atomic Energy Canada Limited, homeowners agreed to be responsible for the long-term care and maintenance of these radon mitigation measures.

Under section 10 of the General Nuclear Safety and Control Regulations, naturally occurring nuclear substancesFootnote 1 are exempt from the Nuclear and Safety and Control Act unless they are or have been “[…] associated with the development, production or use of nuclear energy,” or for the transport, import and export of such materials. The CNSC assesses that the materials in question were never chemically processed; they were simply broken up and moved a short distance from their place of origin. This waste rock is naturally radioactive at levels consistent with the region; it was not subjected to any of the processes of the nuclear fuel cycle. For these reasons, CNSC staff assess that this waste rock consists of naturally occurring nuclear substances that are outside of the CNSC’s regulatory authority.

The CNSC regulates the tailings management facilities associated with legacy uranium mine sites in the Elliot Lake area, and can confirm that these facilities are being operated safely with no significant impacts on persons or on the environment. No tailings from the Elliot Lake mine sites were used as construction material for any of the homes in Elliot Lake, as all of the tailings are currently stored and managed at these tailings management facilities.

Health Canada’s Radiation Protection Bureau, which has a mandate for helping Canadians understand the risks of ionizing radiation, may be able to assist you with the interpretation of the gamma radiation measurements you cite in your letter. The Radiation Protection Bureau also runs the National Radon Program which provides guidance on testing and managing radon levels in homes. The CNSC recommends that Canadians follow that guidance and take any necessary measures to ensure safe indoor air.


Ramzi Jammal
Executive Vice-President and
Chief Regulatory Operations Officer


Footnote 1

The General Nuclear Safety and Control Regulations use the term "naturally occurring nuclear substances", while some other sources use the term "naturally occurring radioactive material". The CNSC considers that these terms can be used interchangeably.

Return to footnote 1 referrer

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