Nova Scotians who participated in radon testing are urging others in the province to protect their health and check their houses for the cancer-causing radioactive gas.

Conny McRiner of Timberlea was shocked to learn her home had high levels of radon: 524 becquerels, or more than double the maximum of 200 recommended by Health Canada. A becquerel is a unit of measurement for radioactivity.

McRiner's husband, Scott, spends his days in their basement where he has a home office.

"That's what really scared me," said Conny McRiner.

"If we weren't in the basement, if it was just where he had a workshop, I wouldn't be as concerned. But where he is down there Monday to Friday, all day working, that is a really big concern for me."

Known cause of lung cancer

Timberlea is an area of Nova Scotia identified as having high levels of the naturally occurring gas, which is created by the breakdown of radium in soil, rock and water.

Long-term exposure to the odourless, tasteless gas is known to increase the risk of lung cancer.

Conny McRiner's home tested high for radon with a reading more than twice the recommended Health Canada limit. (CBC)

McRiner and her husband bought their home less than two years ago. She said if they'd been living there for longer, she would be urging her husband to talk to his doctor.

She recommends others test for radon. As a real estate agent, McRiner said testing can make a difference when it's time to sell.

"You can say, "We had our radon checked. It was high and this is the system we have to protect you and your family when you buy our house.'"

'What would have happened over the years?'

Testing at Carly Brake's Halifax home also identified a problem.

"We have a result of 353 [becquerels], which is above the recommended 200," she said. "They're telling me I have to get remediation done within the next two years to be able to get into a safe zone."

Brake, who has a toddler, said she was surprised by the results.

"As much as you know it can happen anywhere, you still kind of don't think it's going to be you," she said.

Her basement area is used mostly for laundry and storage but she has already contacted companies to get rid of the radon.

Halifax resident Carly Brake and her family plan to stay in their home for a long time. She wonders what the health effects would have been had she not tested for radon and learned she needs to take action against it. (CBC)

"What would have happened over the years?" she said.

"This is our home. We expect to stay here for a long time. Elevated levels over the years would have certainly increased our chances of cancer."

'Peace of mind'

On the other side of the spectrum, Marilyn Martineau of Eastern Passage was delighted with her results, which showed very low levels of radon in her downstairs family room.

Her husband, Denis, spends a lot of time there watching sports.

"Just knowing there could be a silent killer roaming around in your basement is very unsettling and this just gave us peace of mind," she said.

McRiner, Brake and Martineau were three of five homes tested after the Radiation Safety Institute of Canada offered five tests to the CBC as a way of raising awareness about radon and the dangers it can pose.

Marilyn Martineau of Eastern Passage was delighted with her radon results, showing levels well below the acceptable limits. (CBC)

The tests were distributed to the first five people who were interested in participating. Two of the tests showed high results, the remaining three were below acceptable levels.

Lung Association tests show high levels

The Lung Association of Nova Scotia also recently offered free radon test kits to 500 Nova Scotians who live in areas where radon is known to be high. They included Cape Breton, central Nova Scotia, the South Shore, the Annapolis Valley and the Halifax municipality.

"The results we have so far show that about 50 per cent of the homes were actually over the 200 becquerel guidelines which is cause for concern, no question," said Robert MacDonald, a spokesperson for the association.

He said previous studies show that approximately 10 to 15 per cent of homes in the province are usually above the limit but in this case they did target areas that are known to have higher levels.

Radon is everywhere

Radon seeps into homes through sump pump holes, cracks in the foundation, earthen floors or anywhere there's an opening.

There are still people that have not heard of radon and the danger that it can cause. - Robert MacDonald, Lung Association of Nova Scotia

Outside, it disperses to harmless levels. But inside homes it can build up and be very dangerous, particularly when it's inhaled over a significant period of time.

The lung association has said it's estimated 120 Nova Scotians die from lung cancer caused by radon every year.

Still, the problem isn't on everyone's radar.

"There are still people that have not heard of radon and the danger that it can cause," said MacDonald.

Tests easy and inexpensive

Test kits can be purchased through the lung association or at many hardware stores for approximately $40. The association recommends people use long-term kits that stay in place for three months rather than the three-day tests that are also on the market.

The cost of getting rid of radon can vary depending on individual situations.

"Ninety per cent of the work we do costs between $1,400 and $1,500," said Mike Hennessey, the owner of Radon Atlantic.

"Occasionally it can cost as much as $2,500 but I can't remember the last time the bill was over $3,000."