Radon levels exceeding federal guidelines have been found in nearly 40 per cent of homes outside city limits in the Thunder Bay area, which were tested for the radioactive gas.

EcoSuperior announced the findings on Tuesday after studying nearly 500 test kits that had been sold and returned to their office.

Overall, 27 per cent of the kits had radon levels exceeding the established Health Canada guideline of 200 becquerels per cubic metre, with 42 per cent from outside Thunder Bay showing elevated concentrations.

Program co-ordinator Caroline Cox said radon is the second leading cause of lung cancer in Canada, responsible for 16 per cent of cases. Only smoking as a higher prevalence of lung cancer.

The gas, which is colourless, odourless and tasteless, is produced when uranium in soil begins to decompose.

“As it breaks down it can pass through soil and enter homes. It can become trapped and accumulate to levels that can cause lung cancer,” Cox said.

High radon levels were found in surrounding area municipalities such as Neebing, Oliver Paipoonge and Shuniah.

Within Thunder Bay, 32 per cent of homes on the north side of the city tested for elevated concentrations compared to only eight per cent on the south side.

Cox said areas of the city identified last year in a Thunder Bay District Health Unit study as having higher prevalence of radon rates had a greater rate of participation in setting up the home testing kits, which probably factored into the results.

“They found there were a lot of homes testing high in McIntyre, Neebing, Current River and Red River and so the people who live in these areas really responded,” Cox said.

“We actually saw an increase in the number of tests in areas that were already identified as high . . . The areas with high radon are over-represented because people already knew about the high radon and they tested.”

While there are patterns emerging about where high radon levels are prevalent, it’s not necessarily known why that’s the case.

Even within those areas, immediate neighbours can have vastly different results.

“There are a lot of different factors that account for radon. Definitely the soil is one of them, both the permeability and the amount of uranium that’s in the soil,” Cox said.

“But then there also are a lot of factors that have to do with the home such as the building style, decade and water type can make a difference. It’s really hard to pinpoint the reason.”

For homes found to have high levels of radon, there are a number of options.

Homeowners can look at installing a sump pit seal and floor drain traps, which typically cost less $500. More severe interventions can involve an active soil depressurization system, which can cost as much as $3,000.

Cox warned the next few months typically have the highest radon levels.

“The reason radon levels are higher in the winter are because our homes are sealed off so the windows and doors are closed,” she said. “We’re not getting that nice summer breeze anymore. We’re trying to keep our homes warm so they become more sealed.”

EcoSuperior will be hosting a free public radon workshop at the Waverley Public Library on Nov. 21 at 6:30 p.m. where test kits will be available for sale.

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