The dangerous radioactive radon gas in our cities - concept image with periodic table of the elements, magnifying lens and city map on background

Radon: Protecting clients from radioactive gas


Radon, a naturally occurring odourless and colourless radioactive gas, may be out of sight but it certainly shouldn’t be out of mind when it comes to real estate transactions. In fact, radon is present at different concentrations (depending on the makeup of bedrock or sediment) throughout Canada. If radon levels are too high in a home, the health risks are so significant that it becomes a material latent defect.

But understanding radon risks is more than just a professional responsibility under the Real Estate Council of British Columbia’s Professional Standards Manual. It’s an opportunity to give clients peace of mind as they make the biggest financial decision of their lives.

How radon enters a home
Radon typically seeps through the ground and into buildings through cracks in the foundation and/or floor slabs. According to the Canadian Real Estate Association’s Homeowners Guide to Radon, radon can also enter through other openings, like unfinished dirt floors, window casements or gaps around service pipes. Factors like bedrock and soil types, soil moisture level, and seasonal temperature fluctuations also influence indoor radon levels.

Radon and lung cancer
High levels of radon in a home is the second leading cause of lung cancer in Canadians. A report from the Canadian Association of Radon Scientists and Technologists (CARST) explains why:

When inhaled, radon gas particles remain in lung tissue and begin to decay. As the radon particles decay, they release bursts of radiation that can damage the lung tissue cells. Over time, the cell damage can lead to the development of lung cancer.

What is considered a “high level” of radon? While Health Canada advises Canadians to pursue a radon level “as low as reasonably achievable,” 200 becquerels per cubic metre is considered the maximum allowable. There is no lowest threshold, as risk of lung cancer increases with radon concentration. For that reason, the World Health Organization suggests homeowners take action if concentrations are over 100 becquerels.

Testing and mitigation
The good news about radon is that testing and mitigation are relatively affordable and easy. Anyone can test their home for radon. All it takes is a radon testing device that can be found at stores like Home Hardware, Walmart or Home Depot or ordered online from the BC Lung Association’s RadonAware homepage.

While radon mitigation is also relatively straightforward, it’s best to hire a radon mitigation specialist certified by the Canadian – National Radon Proficiency Program (C-NRPP) to take on the job, which can cost between $500 – $3000 depending on the size and style of the home. Fixes can involve improving ventilation, sealing cracks in foundation walls and floors, or installing a depressurization system to draw radon away from the basement.

Your responsibilities as a REALTOR®
Above all, don’t forget that if a property has been tested for radon and shown to have levels above 200 becquerels per cubic metre, this is a material latent defect. If you’re representing a client selling such a property, you must disclose this information in the Property Disclosure Statement. But there’s more to upholding professional standards than just disclosure when it comes to radon. Here’s how you can help:

  • First, educate yourself about radon. There are many good sources such as Health Canada and Take Action on Radon. The Real Estate Council of Alberta has also prepared a checklist for realtors working for sellers and another one for buyers.

  • Educating yourself about radon also means understanding the radon levels in the region where you do business. Health CanadaRadonAware, and the British Columbia Centre for Disease Control all offer great resources.

  • Participate in BC Lung Association’s Radon in Real Estate project. Take an online survey to test your knowledge of radon, learn about upcoming workshops and webinars for real estate professionals, and even watch one-on-one interviews with researchers.

  • Ask sellers if they have had radon testing done. If they have, ask for a copy of the test results. If test results fall below 100 becquerels per cubic metre, this is an added selling feature.

  • If it is 200 becquerels or higher and remediation hasn’t been done, be sure your client understands your duty to disclose this as a material latent defect.

  • If your seller has already done remediation using a C-NRPP certified professional, ask for confirmation that the work has been done and that the radon levels are now in safe zones. Completed remediation is another selling point to highlight.

  • In cases where remediation hasn’t been done, you can add value to your client by connecting them with a C-NRPP certified professional to get the work done.

  • When representing a buyer, consider including a radon holdback (retention) clause in the contract. This involves the buyer and seller agreeing to set aside a sum of money from the purchase price that is likely to be enough to cover the cost of a typical radon remediation system. The money is held by a third party (for example, a solicitor) until the test result is known and any reduction measures have been done. If the test shows low radon levels and that no further action is necessary, the bond money is released to the seller. If the test shows that high radon levels are present and that remediation is necessary, the work is paid for from the bond money; any excess is released to the seller.

  • If your buyer is planning on doing major renovations after buying, make sure they understand that this could impact radon levels in the home, even if it has been remediated in the past.