Quick Read
- One in five Canadian homes has high radon levels, a figure that has more than doubled since the late 2000s.
- Radon-induced lung cancer kills an estimated 3,200 people in Canada annually.
- A national building code update in late December mandates passive radon stacks in newly built homes, pending provincial adoption.
- Testing homes for radon, ideally for 91 days or more during colder months, is the only way to detect the gas.
- Radon mitigation systems cost $2,000-$5,000, presenting a significant financial barrier for many homeowners.
CANADA (Azat TV) – Millions of Canadian homes are currently grappling with dangerously high levels of radon gas, an invisible, odorless, and cancer-causing radioactive element that seeps into residential buildings from the ground. This widespread issue is gaining renewed attention following a significant update to the national building code in late December, which now mandates radon mitigation measures in newly constructed homes. However, the majority of existing properties remain at significant risk, prompting urgent calls for homeowners to test their residences and consider mitigation amidst rising lung cancer deaths attributed to radon exposure.
The Invisible Threat and Its Growing Toll
Federal figures reveal a concerning trend: approximately one in five residential buildings across Canada contains high radon levels, a figure that has more than doubled since the late 2000s. This silent threat is far from benign, as radon-induced lung cancer is estimated to kill 3,200 Canadians each year. Scientists suggest that modern building designs and renovations, which prioritize airtightness for energy efficiency in Canada’s cold climate, inadvertently contribute to increased indoor radon buildup by trapping the gas without adequate ventilation.
Pawel Mekarski, head of radon technical operations at Health Canada, explained to Radio-Canada that while keeping heat inside homes is crucial, many renovations often make buildings more airtight without introducing necessary ventilation. This creates an environment where radon, once it enters a home, can accumulate to hazardous concentrations.
New Codes, Existing Challenges
In a proactive step, a long-awaited update to the national building code was released in late December, requiring newly built homes to incorporate a passive radon stack. This system acts like a chimney, helping to vent radon gas safely outside before it can accumulate indoors. While a promising development, the code sets guidelines for construction projects across the country, but its adoption by individual provinces and territories is still required before it takes full effect.
Mekarski expressed optimism, stating, “We hope to see these systems introduced in future homes in Canada.” However, the immediate challenge remains the millions of existing homes constructed before this code update. For these properties, the onus of identifying and addressing high radon levels falls squarely on homeowners.
Testing and Mitigation: The Path Forward
Experts universally agree that the only way to determine a home’s radon levels is through testing. The process is straightforward: homeowners can either hire a certified radon measurement professional or purchase a DIY test kit. Health Canada recommends a long-term test, ideally lasting between three and 12 months, but a minimum of 91 days, to ensure the most accurate results. Testing during colder months, when windows and doors are typically shut, is also crucial as this period often sees higher indoor radon concentrations.
Should a home’s readings exceed the national guideline of 200 becquerels per cubic meter (Bq/m3), mitigation is recommended. Mitigation systems typically involve installing a pipe that runs from the foundation floor through the roof, equipped with a small fan to draw radon from beneath the house and vent it outdoors. These installations usually take less than a day.
Addressing the Cost Barrier
The cost of installing a radon mitigation system can range from $2,000 to $5,000 or more, depending on the home’s size, structure, and location. This expense often presents a significant barrier for many Canadian households, as noted by Sarah Butson, CEO of the Canadian Lung Association. “We know that cost is a significant barrier to people actually taking action on radon,” Butson told Radio-Canada, highlighting that financial concerns can even deter individuals from testing their homes in the first place.
While some regional support exists, such as Ontario’s home warranty program covering mitigation for up to seven years post-construction, and Manitoba’s unique financing program allowing costs to be spread across hydro bills, these are not universally available. The Canadian Lung Association offers the only cross-Canada grant program to help low- and middle-income households, providing approximately $150,000 to around a hundred homes last year. Butson emphasized that this is “just a drop in the bucket” compared to the widespread need.
Community initiatives are also emerging to bridge this gap. For instance, Citizens for Clean Air (CCA) is lending out free Airthings Corentium digital radon monitors, thanks to donor generosity throughout 2025, enabling more residents to test their homes without initial cost.
For individuals like Dr. Kong Khoo, an oncologist with B.C. Cancer who was diagnosed with Stage 1 lung cancer in 2020 and later discovered sky-high radon levels in his home, the cost of mitigation is a small price for peace of mind. “It’s vital for every single homeowner to do that, to protect themselves and their families, because there’s no other way you can find out if you’re at risk,” Khoo stated, underscoring the critical importance of early detection and action.
The recent update to Canada’s national building code marks a crucial policy step towards safer new constructions, yet it starkly highlights the ongoing public health challenge posed by radon in existing homes. The disparity between proactive measures for future buildings and the reactive, often financially burdensome, responsibility placed on current homeowners underscores the need for more comprehensive, accessible, and subsidized programs to protect millions of Canadians from this silent killer.