Radon levels vary wildly in Thunder Bay, depending on where in the city one resides.
A local soil-gas study conducted in 2014 shows 43 per cent of all homes in McIntyre Ward showed radon levels above 200 becquerels per cubic metre, Canada’s threshold for safety. Thirty per cent of Neebing Ward residents were over the limit.
In contrast, none of the homes in Westfort Ward showed unacceptable levels of the gas. Red River (15 per cent) and Current River (13 per cent) were also higher than expected, with Northwood (three per cent apiece) and McKeller (six per cent) under the average.
Overall the study showed 16 per cent of city homes tested were above the government’s high-water mark, a 33 per cent increase over the 12 per cent found in a 2012 Ontario-wide study. The Canadian average is 6.9 per cent, a number that drops to 4.6 per cent in Ontario.
The results are surprising said Lee Sieswerda, manager of environmental health programs at the Thunder Bay District Health Unit.
“We expected a certain amount of variability in the city, but we certainly didn’t expect it at that degree,” Sieswerda said.
The study, however, wasn’t designed to provide explanations for the variations.
“It was a prevalence study, so it was to determine the levels. We’ll have to do further research to discover why it is that way.”
According to Health Canada, radon is a radioactive gas produced by the decay of uranium in soil, rock or water. It’s odourless and tasteless and when confined in small spaces if it seeps into a building, it can pose a health risk.
Long-term exposure can lead to lung cancer.
The study shows the risk level could correspond to a home’s age.
“Homes that were built before 1945, before World War II, tend to have quite low levels of radon. It escalates to much higher levels between the 1990s to the early 2000s, and the very newest homes again have relatively low levels of radon.”
Recognizing the issue, the City of Thunder Bay has taken steps to prevent radon from entering newly constructed homes.
Desmond Stolz, the muncipality’s manager of building services, said they’ve made changes to the building code to counteract the problem.
“We’re requiring all new houses to have an enhanced radon barrier beneath the floor slab, which would include a six-millimetre poly sheet. We’re also requiring (all) penetrations that come through the floor to be sealed,” Stolz said on Wednesday, when the health unit revealed the results of the study to a packed house.
“We’re also asking for an exhaust pipe to be installed below the floor.”
Homeowners who find high radon levels in their homes can have the problem remediated, usually at a cost between $500 and $3,000.
It depends on the individual situation, said Doug Steele, manager of environmental services at TBT Engineering, whose company has been fielding calls from concerned residents since the study results first became public.
He’s anticipating that volume to go up further, but cautioned city residents not to panic.
“Don’t board up your windows, don’t board up the house or put it up for sale,” he said.
Recommendations from the study include encouraging people to have their home tested, either through a do-it-yourself kit or with the help of a professional, something the health unit and its partners intend to promote. They also plan to target landlords and tenants and ask upper levels of government to help fund more studies and provide programs to help cover the cost of remediation.
