Radon testing in Thunder Bay

Health Canada's 2012 survey found 12% of 108 homes tested in the Thunder Bay District Health Unit health region above the guideline. The larger 2024 Cross-Canada survey reports 34.3% (1 in 3) of houses at or above the guideline for the Thunder Bay, ON (Thunder Bay CMA) metro area.

The two surveys aren't directly comparable: the 2024 study pooled about 69,000 volunteer tests and more of them were taken in basements, which partly explains its higher numbers. Neither can tell you about a single house, because neighbouring homes can differ widely.

• Use a long-term test of at least three months, with most of it in the heating season, which gives the most conservative result.
• Place the detector in the lowest level you spend four or more hours a day in, away from drafts, and follow the kit's instructions.
• If the result is above 200 Bq/m³, Health Canada recommends fixing it within a year, sooner if it's much higher.

Our full radon testing guide.

• There's no provincial free-kit program, but many Ontario public libraries lend digital radon monitors free with a library card, among them Hamilton, Vaughan, Guelph, Kingston Frontenac, Greater Sudbury, Thunder Bay, Brantford and Waterloo.
• For a professional measurement or mitigation, search the C-NRPP directory by your Thunder Bay postal code; it lists certified measurement and mitigation professionals.

• Since January 1, 2025, the Ontario Building Code requires new houses to include a soil-gas barrier and a radon rough-in.
• Tarion's new-home warranty covers radon remediation for seven years from possession, and the Canadian Lung Association's Lungs Matter program offers up to $1,500 toward mitigation for households with low to moderate incomes or a lung cancer diagnosis.
• If your level is high, mitigation (usually a sub-slab depressurization fan system installed by a C-NRPP-certified professional) typically costs $2,000–$4,000.