The Huron County Health Unit is urging residents to consider testing their homes for radon.
Eleven per cent of randomly selected homes in Huron County tested above the Canadian Guideline for radon in 2012.
Public Health Inspector Chris Boyes said radon is a naturally occurring radioactive gas in the ground.
Radon released from the ground into the air is not a concern, but in enclosed areas radon levels can build up and be harmful to health.
"If you are in an environment with high radon levels, for a very long period of time, like 20 years or so, then your chance of lung cancer is increased based on the amount of radon in your environment," said Boyes.
Long-term exposure to elevated levels of radon is the second-leading cause of lung cancer after smoking. Radon can be found all over Ontario.
"Radon is very common, but the only way to know what level of radon is in your house is to test for it," said Boyes. "Radon test kits are available at most major home renovation stores, or can be purchased online. Taking appropriate measures to reduce radon levels from your home could greatly benefit your health.
"If it tests over the recommended limit of 200 becquerels per cubic metre, then to remediate it is essentially just removing air from your home."
Health Canada recommends homeowners do a long-term radon test over three months during cold weather.
To get the most accurate results, the radon detector should be placed in the lowest level of the home where homeowners spend a minimum of four hours per day.
If it's positive, exhaust systems can be installed to lower radon levels in the home.