A toxic gas was hiding inside his home for decades. It’s radon, and scientists are tackling its deadly rise | CBC News

When Steve Blake moved into his brand new home in 1995, he felt lucky. 

The house was well-built. Solid construction. No leaks. The basement was comfortable enough to work in, so every weekday morning, after seeing his kids off to school, the Calgary financial advisor set up shop downstairs in his home office.

Blake kept up that routine for more than a quarter-century, spending roughly six hours a day, five days a week, in the basement.

He had no idea it could be slowly killing him.

In 2023, at the age of 55, he developed a nagging cough. Blake didn’t worry much at first; he felt healthy, biked regularly and had a reputation as one of Alberta’s top golfers. 

Then one morning, while gearing up to play a round, the father of two struggled to catch his breath. Doctors later told him devastating news: he had inoperable Stage 4 lung cancer and only 12 to 14 months to live. 

Blake and his wife, Kelly, were stunned. Blake had never smoked or even been around secondhand smoke. The couple started doing research, trying to figure out what could have led to such a grim prognosis.

One word kept coming up: radon.

This odourless, invisible and highly toxic gas can build up inside your home. When Blake installed a radon monitor in his basement late last year, its average readings over the winter months were consistently high.

“There’s no test or bloodwork they can pull from me that would conclusively say, ‘It was your basement that gave you this cancer, it’s the house that’s going to kill you,’” Blake said during an interview in December with CBC News. Still, the possibilities haunt him. 

“What was I breathing in, for so long, all those years?”

Yearly radon-induced lung cancer death counts likely in the thousands

No one wants to imagine their home could threaten their health, but when radon seeps in, that’s exactly what happens. 

This naturally occurring gas is released from the ground as the uranium in soil and rock breaks down. It isn’t a health concern when it’s diluted in the air, or if someone’s home has a radon mitigation system to safely funnel the gas outside.

But when radon builds up indoors and is inhaled over time, it exposes people to radiation that wreaks slow and steady havoc on their lung cells. 

Radon-induced lung cancer kills an estimated 3,200 Canadians each year, and lung cancer, in general, remains the deadliest type of cancer in Canada, even as smoking rates have dropped dramatically in recent decades.

Yet radon isn’t included in cancer screening criteria since — as Blake says — there’s no existing test to prove that someone has had dangerous, long-term exposure.

A group of cross-Canada scientists are now hoping to change that, by developing innovative ways to test for radon exposure using something most of us throw away: toenail clippings.

Dustin Pearson, the University of Calgary-based research operations manager for the Evict Radon study, acknowledges studying toenails might sound “a little weird” at first, but there’s a good reason for it. 

“There’s something in them that we can actually measure,” he explained.

When you inhale radon, it turns into a type of radioactive lead that is shed in slow-growing bodily tissues like your skin, hair and nails. (Toenails in particular have the least exposure to chemicals and cleaners that could contaminate the samples.)

Team collecting 10K toenail samples

The team is aiming to collect 10,000 samples from across the country, along with radon monitoring data from participants’ homes. 

This phase of the research, funded by the Canadian Cancer Society and set to conclude by 2028, is meant to confirm promising results from a much smaller study that showed nail clippings contain more than a decade’s worth of measurable lead.

Biochemist Aaron Goodarzi, a professor at the University of Calgary’s Cumming School of Medicine who leads the Evict Radon project, said his team is expecting a “tsunami of toenails” in the year ahead. 

When those samples come in, they’re broken down with strong acid inside a special metal-free lab. The resulting toenail mixture — a “slurry” or “soup,” as the team calls it — is passed through a sealed slot to be analyzed in a mass spectrometer, a large device that uses electric and magnetic fields to separate lead from any other chemical elements that might be present.

The goal is finding a way to show someone’s individual, long-term radon exposure, in the hope of influencing lung cancer screening criteria that, to date, focuses on moderate and heavy smokers.

“We’re looking for a radon signature in that tissue so we could develop a noninvasive or minimally invasive test to determine people’s lifetime exposure to radon, to include them in screening criteria,” said team member Dr. Alison Wallace, a thoracic surgeon and researcher based in Halifax.

The timing is crucial, as Canadian medical teams are “now seeing a shift in more and more never-smokers developing lung cancer,” she said.

4 in 10 households unaware of radon

Despite the links to cancer, there’s limited understanding of the rising risks of radon in Canada.

“There’s very poor public awareness… and so most people don’t go looking for it,” noted Dr. Christian Finley, co-chair of the National Lung Cancer Action Plan with the Canadian Cancer Society and a thoracic surgeon with McMaster University in Hamilton, Ont.

More than four in 10 households remain unaware of radon, federal figures show, even as the latest Cross-Canada Radon Survey, released by the Evict Radon team in 2024, suggests roughly 10 million Canadian households may be at risk.

And the problem is getting worse.

The research found close to 18 per cent of residences in Canada have radon levels at or above the current national guideline of 200 becquerels — the standard unit of radioactivity, which refers to the rate of nuclear decay — per metre cubed (Bq/m3). It’s a jump from roughly seven per cent of houses in the late 2000s.

Scientists suspect that rise is due to modern building techniques, which make homes more airtight to capture heat on purpose — and, by extension, radon.

Limited lung cancer screening in Canada

While more public awareness and home mitigation efforts could prevent people from being exposed to radon in the first place, the risk remains across the country. The ultimate goal of Evict Radon’s years-long toenail research, Goodarzi said, is to save lives.

Long-term exposure to radon’s radiation absolutely “bulldozes” cellular DNA, yet most people don’t even realize they’re developing lung cancer in the early stages, he added. This fiendish form of cancer is often caught late as symptoms don’t show up early on, and when they do, they’re often similar to a host of routine respiratory infections. By that point, the cancer is typically widespread.

On the flip side, if it’s caught early, lung cancer can often be cured through surgery and other treatments, and many patients go on to lead long lives, said Finley, the thoracic surgeon from McMaster University. 

Despite the advancements in treatments, only B.C. and Ontario have permanent lung cancer screening programs to catch cases early on — with narrow eligibility that includes moderate or heavy smoking.

B.C. is also the only province operating a pilot project that screens people living in homes with high radon levels. 

Operated by the B.C. cancer agency, the “first of its kind” trial focuses on non-smoking people who live in homes with radon levels of 800 Bq/m3 or more, or at least four times the Health Canada guideline, notes the National Collaborating Centre for Environmental Health.

Health Canada is trying to encourage other provincial screening programs to consider radon in their criteria “so that Canadians who are exposed can be screened for lung cancer,” said Kelley Bush, the federal department’s manager of radon outreach. (Health Canada’s National Radon Program also collaborates with the Evict Radon study.)

‘It’s worth the money’

Back in Calgary, Steve and Kelly Blake struggled to understand why all levels of government aren’t doing more to protect homeowners from the risks of radon. Expanded cancer screenings across the country could help catch more lung cancer cases early before it’s too late, Kelly said.

“If we get more information on radon gas and the potential risks, you’re going to get more data and eventually that could be a criteria — a risk factor — so that a non-smoker can go get early screening,” she said.

Blake, who is hoping to live as long as possible through every available cancer treatment, can’t shake the feeling that his house was always a danger zone.

Standing in his basement in December, with his radon monitor blinking red over and over behind him, Blake said he wished he’d known more about radon when he first built the house. 

He and Kelly planned to have a mitigation system installed the following week, at a cost of roughly $2,600.

“For us,” he said, “it’s worth the money.”