What is Radon?


A colourless, odourless radioactive gas found naturally in the environment, Radon is produced by the natural breakdown of uranium commonly found in Ontario soils and rocks. As a gas, Radon can easily move through small spaces in soils and other materials, allowing it to enter buildings. Radon gas is approximately 7 to 8 times heavier than air, and tends to accumulate in low, poorly ventilated areas such as basements or crawl spaces. If radon accumulates to high levels, it can pose a risk to health.


It is estimated that about 16% of lung cancers in Canada are related to radon exposure. This has prompted concern that radon levels in some Ontario homes, workplaces and buildings may pose a health risk. The level of risk depends on:

  • the amount of radon present
  • the length of exposure
  • whether or not you smoke



Radon Fast Fact
This fast fact includes a summary, a Radon potential map of Ontario, an in-depth explanation of Radon and suggestions to minimize risks in homes and workplaces.
Radon Awareness Webinar
This webinar provides a high-level overview of the proposed Radon Awareness and Prevention Act, 2014, its intent and the current status. It will also provide insight into actions employers should take to be aware of and prepare for this possible legislation. This webinar is presented by PSHSA and guest speakers from the Radiation Safety Institute, Steve Mahoney and Laura Boksman.