Radon in Sarnia
Sarnia sits where Lake Huron drains into the St. Clair River, across from Port Huron, Michigan.
Sarnia radon guide
Radon in Lambton
Radon testing and mitigation in Lambton
Sarnia and the St. Clair River, the Lake Huron shore from Point Edward toward Grand Bend, and farm country over the Kettle Point shale.
Radon in Lambton
Lambton County runs from Sarnia and Point Edward at the foot of Lake Huron, down the St. Clair River through Corunna and Sombra, and along the Lake Huron shore through Bright’s Grove, Kettle Point and Port Franks to Grand Bend. In the Health Canada survey data that Cancer Care Ontario tabulated by public health unit, 8.4% of the homes tested in Lambton were at or above the 200 Bq/m³ guideline. That is about one home in twelve, and it describes the county, not a street.
What’s under the ground
Lambton sits on glacial clay plain and moraine ridges, with sandy dune and beach deposits along Lake Huron. Underneath, the bedrock includes the Kettle Point Formation, a black shale that Ontario Geological Survey drill core puts at over 30 ppm uranium on average. It crops out on the lakeshore at Kettle Point and runs beneath Lambton and western Middlesex under a cover of glacial deposits, so its effect at any one house varies.
The homes
Sarnia grew with the petrochemical industry, and much of its housing is post-war: bungalows and storey-and-a-half homes with basements that have been finished over the decades. Bright’s Grove and the Lake Huron shore mix older cottages with newer year-round homes, and rural Lambton is farmhouses and acreage properties, mostly on private wells.
Public health: Lambton Public Health.
What the data says
8.4%
Of homes tested in the Lambton health unit area were at or above 200 Bq/m³ in the Health Canada survey data tabulated by Cancer Care Ontario (2009 to 2013).Source: Cancer Care Ontario — Risk of Residential Radon Exposure Varies Geographically (results by public health unit, Health Canada survey data 2009–2013)
1 in 8
Ontario homes at or above Health Canada’s 200 Bq/m³ guideline in the 2024 Cross-Canada Survey, more than double the share found a decade earlier.Source: Cross-Canada Survey of Radon Exposure in the Residential Buildings of Urban and Rural Communities (2024)
+30%
Higher average radon exposure for rural residents than urban residents in a 2024 national study of 42,051 homes, mostly linked to drilled wells.Source: Goodarzi et al., Scientific Reports (2024) — rural communities and drilled-well annuli
Local factors
Why Lambton homes should test
Uranium-bearing shale nearby
Black shale is the most common uranium source rock in southern Ontario. The Kettle Point shale that runs under Lambton and western Middlesex and Elgin averages over 30 ppm uranium in Ontario Geological Survey drill core, roughly ten times a typical rock.
Clay plains
Dense clay slows soil gas, but it cracks in dry spells. Gas then follows the easiest route: the gravel backfill, weeping tile and utility trenches that lead straight to a basement.
Rural homes on drilled wells
A 2024 national study of over 42,000 homes found rural residents were exposed to about 30% more radon than urban residents, with most of the gap linked to drilled wells. Researchers suspect gas travels up the gap around the well casing.
Cottages and crawlspaces
Lakeshore cottages converted to year-round homes often sit on crawlspaces, piers or patched slabs. Once winterized and heated, they can start pulling in soil gas they never did as summer places.
Century homes
Fieldstone, rubble and early concrete foundations, earth-floor cellars and open sumps give radon many ways in. Older doesn’t mean safer: these homes still need a test.
Communities
Where we work in Lambton
Questions
Radon in Lambton: common questions
Is there a lot of radon in Sarnia and Lambton County?
The published county figure is 8.4% of homes tested at or above 200 Bq/m³, in Health Canada survey data tabulated by Cancer Care Ontario. The county also sits over the Kettle Point black shale, a uranium-bearing rock. Neither tells you about your house, and a 91-day test does.
Do you serve Grand Bend, Petrolia and the Lambton Shores?
Yes. We test and mitigate across Lambton County, including Sarnia, Point Edward, Corunna, Petrolia, Forest, Grand Bend and Port Franks.
Book a radon test in Lambton
C-NRPP certified testing and mitigation across Sarnia.