Radon Testing/Mitigation

Last updated on July 3, 2025

Radon is a gas that has no colour, odour or taste. It is produced by the radioactive decay of uranium in soil, rock and water. Radon is found in almost all parts of Canada.

Radon:

  • Can find its way into any building where the foundation is in direct contact with the soil
  • Can get trapped indoors and accumulate to high levels
  • The only way to know if a building has high levels of radon is to test

While many Canadians have never heard of radon, it is the second-leading cause of lung cancer (after smoking) and the primary cause of lung cancer among non-smokers. Additionally:

  • Radon has been shown to cause lung cancer after years of exposure to high levels
  • Exposure to high levels of radon over many years leads to an estimated one in 20 lifetime risk of developing lung cancer

For more information about radon's health effects, read Radon and your health (PDF 281KB).

In 2007, Health Canada established a health guideline of 200 Bq/m3 (Becquerels per cubic metre) for a residence. In a home where radon levels are recorded in the 200-600 Bq/m3 range, Health Canada recommends taking action to reduce the levels within two years. Health Canada recommends that radon levels over 600 Bq/m3 should be addressed within one year.

Real Property Division (RPD), has tested government-owned, managed and leased buildings since 2015/16. If you work in a building that was tested and exceeded the Health Canada guidelines, once the radon mitigation is completed the building will be retested the following winter to ensure radon levels are below the recommended guideline. Testing will then be completed every five years or after any major renovations to the building.

For more information about testing, read Radon testing and mitigation (PDF 256KB).

If you have any questions about test results or radon in general, contact an Occupational Health and Safety Specialist via AskMyHR. Submit a service request with the category Myself (or) My Team/Organization > Workplace Safety > Safety Training & Support.