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You can’t see it, and you can’t smell it, radon is a naturally occurring, cancer-causing gas that may be a problem in your home.  While it can be found almost anywhere, it is of greatest concern when radon seeps into an indoor living space. Any building can have a radon problem, but you and your family are likely to have your greatest exposure to radon in your home, as this is where you spend most of your time.

Radon is the number one cause of lung cancer among non-smokers, and the second leading cause of all lung cancers.  According to Public Health Ontario (PHO) estimates, radon is causing 847 lung cancer deaths per year in Ontario (Public Health Ontario (2013), Radon Burdon of Illness). About 135 of these deaths occur among people who have never smoked. If you smoke and your home has high radon levels, your lifetime risk of lung cancer is especially high (Government of Canada (2010), Radon - Another Reason to Quit).

Health Canada estimates that 1 in 20 Hamilton homes will have radon levels above the recommended guideline value of 200 Bq/m3 (Becquerel’s per cubic metre) Health Canada (2012), (Cross-Canada Survey of Radon Concentrations in Homes). Because radon can be found across Hamilton, any home could have a radon problem. This includes new, well-insulated homes, old drafty homes, and homes with or without basements. Radon enters the home from the ground, and the highest radon concentrations are found below the second floor. The only way to know if your home is safe is to test your home for radon.

Lung Cancer risk Smokers and high radon is 1 in 3, non-smokers and high radon is 1 in 20

Detect Radon

You can’t see radon, but it is easy to detect with a simple, inexpensive test.  You may choose to test your home yourself or you can hire a qualified radon testing professional.  Either approach takes only a small amount of effort.

Do-it-yourself tests
There are several types of devices to test your home, but one device commonly used by homeowners is the “alpha track” radon detector, available from your local hardware store, and some on-line retailers.  Follow all of the instructions that come with your test kit.  The detector must be mailed back to a laboratory for analysis at the end of the test. 

Hiring a qualified professional
Contact a Canadian National Radon Proficiency Program (C-NRPP) certified  radon measurement professional in your area.  The C-NRPP certified professional will advise you on what type of radon detection device best meets your current needs.

How long to test for radon
Long-term tests, lasting anywhere from 91 days to 365 days, will give you a dependable reading of your actual radon risk at home.   If choosing to perform a long-term test less than the maximum of 365 days period, be sure that the test period includes the winter season, when the homes heating system is being used.

Short-term tests are useful at quickly assessing the possible long-term exposure level, and to confirm the successful installation of radon mitigation systems, when long-term testing has confirmed that radon was a problem.  Depending on the device, it may be used anywhere from 2 to 90 days.  Because radon levels can change from day to day, and season to season, a short-term result is less able to assess your long term, year-round average radon risk.  If you are using a short-term test device, Hamilton Public Health recommends testing for a minimum of 7 days, and keeping outside windows and doors closed as much as possible during the test period.  For periods shorter than 7 days, it is recommended that you consult a C-NRPP certified professional to conduct the test. 

Where to test for radon
The test device should be placed in the lowest lived-in level of the home, where people typically spend 4 or more hours per day.  For example, in an unfinished basement, with only a laundry room and storage area, the device should be placed on the first floor of the home.  Lived-in areas of the home, such as family rooms, dens and bedrooms are suitable locations.  Avoid placing the device in a kitchen or bathroom.  Also, be sure to follow all of the instructions that come with your test kit (i.e. any specified distance away from the floor, ceiling, exterior walls, doors and windows, vents, or sources of heat).

What your test results mean
Lower radon levels are better.  If you have conducted a short-term test (less than 91 days), you should still consider following up with a long-term test, before concluding that you do or do not have a radon problem in your home.  For long-term test results over 100 Bq/m3, you may consider taking action to lower your radon level.  Above 200 Bq/m3, it is recommended that you lower your radon levels within 2 years.  Over 600 Bq/m3, it is recommended that you fix the problem with 1 year.  For help interpreting your test results, you can contact Hamilton Public Health Services at 905-546-2489.

Protecting your family from radon

Should you discover that radon is a problem in your home, radon reduction systems are effective, and even very high radon averages can be reduced to safe background levels.

The Canadian Mortgage and Housing Corporation (CMHC) have published Radon - A Guide for Canadian Homeowners, which details various ways to reduce radon in your home.  The right solution for your home depends on a number of factors, and some solutions require technical knowledge and special skills.  The Canadian National Radon Proficiency Program (C-NRPP) lists contact information for contractors who are qualified radon mitigation professionals (search for “Mitigation Professionals” in the search bar).

The cost of reducing radon may vary depending on the extent of the problem, and between different contractors, so you may want to get more than one estimate.  Most homes can be protected from radon for about the same cost as other common household repairs.

Take the True or False Radon Quiz


While radon may only be a problem in about 5% of homes, where radon has been  identified as a problem, levels can be 5 times higher than the Health Canada recommended guideline value.


Radon levels can vary greatly from home to home.  The only way to know if your home is safe is to test your own home for radon.


You will reduce your risk of lung cancer when you take action to reduce radon levels in your home, even if you have lived with high radon levels a long time.  If you smoke, quitting will also reduce your risk of lung cancer from both smoking and radon.


While smoking is the number one cause of lung cancer, radon is the number one cause of lung cancer in non-smokers.


High radon levels have been found in all regions of Ontario, including Hamilton.

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