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Radon Exposure

IS THERE A KILLER IN THE HOUSE, OR EVEN YOUR WORKPLACE? Gasp! More people die from radon gas in this country than from car accidents. And yet, 96% of us still don’t test for it. Caused by the breakdown of uranium in the soil, radon is the second leading cause of lung cancer after smoking. Seeping into the house through drains, cracks and crevices in the foundation, this radioactive gas escapes detection because it is both colourless and odourless. Get your house or workplace tested for radon. And don’t forget to tell the neighbours, too.

What is radon?

Radon is a colourless, odourless gas that is produced from the natural breakdown of uranium in rocks and soil.

Radon in your home

Radon can enter a home through tiny openings in floors and foundations and build up to dangerous levels. Long-term exposure to radon is the second leading cause of lung cancer in Ontario, linked to 850 lung cancer deaths each year.

Testing for radon

Every home in Ontario should be tested for radon, no matter where it is located. It’s easy:

  • You can purchase a do-it-yourself test kit from The Lung Association or home improvement retailers (look for long-term kits that allow for at least a three month testing period)
  • Hire a certified radon professional.
  • To find out more details about testing, click here.

What if my radon levels are high?

The Canadian guideline for indoor radon is 200 becquerels/m3. Action should be taken to reduce the radon level if it reports back higher than 200 Bq/m3. Find a certified radon professional here.

Public Service Announcement by Mike Holmes Jr.

Health-care professionals

Are you a health-care professional interested in learning more about radon? Take an online course from machealth that will educate you on how to answer your patients’ questions about radon and the health risks.

Radon in your workplace

We spend a significant portion of our time at work. The health and safety of our workspace is important. That’s why a first of its kind study in Ontario is seeking to understand how exposed Ontario workers are to radon in the workplace.

Radon is a radioactive gas. It is invisible; you can’t see it, smell it, or taste it. All buildings have some level of radon, the question is “how much?”. This is an important question as radon is the 2nd leading cause of lung cancer. The health risks from radon exposure are not immediate but the result of long term exposure.

The only way to know if a high level of radon is present in a building is by testing. If test results show radon levels above the recommended guideline of 200 Bq/m3 actions must be taken to reduce concentrations.

If you own or work in a small to medium sized business, your workplace may be eligible for free radon testing by a C-NRPP certified professional. Simply send an email to dshurgold@lungontario.caor Elizabeth.rydz@occupationalcancer.ca.

About the Radon Study: Recruiting NOW!

This study seeks to test 500 workplaces over the next 2 years to better understand radon exposure in the workplace. The data gained from this study will be used to fill crucial gaps in current research and to produce a radon map for Ontario. These tools may help identify groups of workers who may be at increased risk of lung cancer from radon in the workplace. This information will help build better prevention and education efforts, as well as shape improvements in occupational health and safety.

Click Here to find out if your business qualifies to get free radon testing and be part of this important study.

How Does the Study Work?

Interested participants will complete an eligibility survey to ensure they meet study requirements. Once a business has been included then follow up educational resources will be provided. Next, a C-NRPP certified professional will visit the business and place the radon monitoring kit. This kit is a very small device that will measure radon levels over the course of 3 months, at which point the certified professional will retrieve the kit, test results will be analyzed and shared with the business. Individual results will not be publicized and only aggregate data will be used in study reports on findings.

Workplaces with higher levels of radon will be provided free educational materials and connections to remediation and mitigation services.

If you are interested in testing your business but do not meet the criteria for the study you may still be eligible for a discounted radon monitoring kit through The Lung Association. Contact sbutson@lungontario.ca to learn more.


  • A study FAQ for business owners and workplace managers
  • A fact sheet that describes radon, its health effects, and radon testing and mitigation in the workplace


The study is funded by a grant from the Ontario Ministry of Labour Research Opportunity Program.
Demers PA, Boksman L, McIntosh T, Nicol AM. Radon Survey of Workplaces in Ontario. 2017-2019.

Our investigators:

Paul A Demers (Occupational Cancer Research Centre, University of Toronto)
Laura Boksman (Radiation Safety Institute of Canada)
Sarah Butson (The Lung Association – Ontario)
Anne-Marie Nicol (CAREX Canada, Simon Fraser University)
Ela Rydz (Occupational Cancer Research Centre)

For more information:

If you would like more information or are interested in participating in the study, please contact Sarah Butson (sbutson@lungontario.ca) or Ela Rydz (Elizabeth.rydz@occupationalcancer.ca).