Local risk

Is your Thunder Bay home at risk?

The health unit tested homes across the city. The share above the Health Canada guideline changes a lot from ward to ward.

16%

of City of Thunder Bay homes tested at or above the guideline. Canada 6.9%, Ontario 4.6%.

TBDHU 2014/15 city study

12%

across the Thunder Bay District Health Unit area, about half again the Ontario rate.

Health Canada 2012 cross-Canada survey

65%

of tested homes in Oliver Paipoonge, outside the city. Marathon 17%.

TBDHU 2017/18 rural study

By ward

McIntyre43%
Neebing30%
Red River15%
Current River13%
McKellar6%
Northwood3%
Westfort0%

Share of tested homes at or above 200 Bq/m3, TBDHU 2014/15

Health Canada guideline200 Bq/m3 as a yearly average. Above it, Health Canada says fix it. Health Canada
Certified installers onlyEvery installer we work with is C-NRPP certified.

What we do

Test first, then fix

A test tells you the number. A system brings it down. We handle both, with certified people at every step.

Radon testing

A long-term test kit sits on the lowest lived-in floor for 91 days or more, best in the heating season, then goes to a lab. Kits are sold in Thunder Bay for about $50, and the public library lends digital detectors.

How testing works

Radon mitigation

A sub-slab system, put in by a C-NRPP certified installer, usually in one day. In most homes it cuts the radon level by more than 80%. We retest after to confirm it works.

How a system works

What radon does

Radon is a radioactive gas. It forms when uranium in soil and rock breaks down, and it seeps into homes through cracks in the slab, the sump pit, floor drains and gaps around pipes. You cannot see it or smell it. The only way to know your level is to test.

Health Canada estimates that radon causes about 16% of lung cancers in Canada, more than 3,000 deaths a year. People who smoke and live with high radon carry a higher risk again. Health Canada fact sheet

The Health Canada guideline is 200 Bq/m3 as a yearly average. Between 200 and 600, Health Canada says fix it within two years. Above 600, within one year. TBDHU

Any home can have radon, old or new, with a basement or on a slab. Your neighbour’s result does not tell you yours. Two houses on the same street can test very differently.

Cross-section of a house: radon rises from the soil and enters through cracks in the slab, the sump pit, a floor drain, gaps around pipes and the wall-floor joint.

How a radon system works

Sub-slab radon system: a sealed pipe through the basement floor, a fan on the pipe in the basement, and an exhaust out through the side wall above grade. A U-tube gauge on the pipe shows the fan runs.

The fix is a sub-slab depressurization system. A certified installer drills a hole through the basement floor, seals a pipe into it, and runs the pipe to a fan. The fan pulls the gas from under the slab and sends it outside, usually through the side wall of the house. In some homes it runs up through the attic or garage and out above the roof. Health Canada calls this the most common method. It can be installed in less than a day, and in most homes it cuts the radon level by more than 80%. Health Canada

Three steps:

Test for 91 days or more, in the heating season.
Install the system, usually in one day.
Retest to confirm it works. Retest again within five years and after any renovation. C-NRPP

Sealing cracks on its own is not a fix. Health Canada says sealing helps, but how much depends on how high your level is.

FAQ

Questions people ask

Remediation, mitigation, removal: are they the same thing?

Yes. All three mean lowering the radon in your home with a system. Installers say mitigation.

Is there a radon map of Thunder Bay?

The ward table on this page is the closest thing. It comes from the health unit's 2014/15 study of tested homes, ward by ward. Two homes on the same street can still test differently, so the table tells you to test, not to skip it.

Is radon mitigation loud?

The fan runs all the time and makes a low hum close to it. Installers put it in a utility room, an unfinished part of the basement, an attached garage or the attic, away from bedrooms.

When should I retest?

Right after the system goes in, to confirm it works. Then within five years, and after any renovation that touches the foundation or the heating system.

I am buying a new build. Does it already have a radon system?

Probably not. Since April 1, 2025 the Ontario Building Code requires a radon rough-in in new houses. A rough-in is a capped pipe under the slab, not a working system. Test the house. If it is high, Tarion's warranty covers radon in homes under seven years old.

All questions

Next step

Get a quote or book a test

Send the form and we call you back the same working day. No cost, no obligation. Prefer to talk? Call 807-696-2005.

Radon mitigation in Thunder Bay