Radon gas is an odourless, colourless and tasteless gas that seeps into your home from the surrounding soil. It can cause lung cancer if exposed to it for long periods of time, such as several years in an affected home.

Even though the City of Guelph implemented a radon gas mitigation program in 2015, Wellington-Dufferin-Guelph Public Health (WDGPH) says not enough people are getting their homes tested.

"Generally we feel like there isn't a lot of awareness on this important issue," said Shawn Zentner, Manager of Health Protection for WDGPH. "That's part of why we did an event last year and and are doing an event this year."

Last November, the City of Guelph Public Health team hosted a public information session on radon gas training. This year, Guelph held the first of three information sessions on Nov. 3, with 118 people attending. Orangeville and Fergus will follow with their session on Nov. 9 and 23. 

A 2012 Health Canada study showed that 18 per cent of homes in Wellington-Dufferin-Guelph that were tested, showed having higher levels of radon than Canada's recommended guideline and higher levels than the national average.

Health Canada's radon gas guidelines sit at 200 becquerels per cubic metre (Bq/m3), a measurement that measures radioactive activity. One of the Guelph homes tested showed radon levels of 984 Bq/m3, almost five times the recommended measure.

About radon

Radon is formed naturally and is produced by the breakdown of uranium found in dirt and rocks beneath homes.

Once released, the invisible gas seeps up through the soil and either gets released into the atmosphere or is drawn in through the basement foundation into a home.

As bathroom ventilation units, exhaust fans on stoves and clothes dryer vents blow air out of the home. That creates an air pressure draw, pulling replacement air into the house. Some of that replacement air comes from the soil around the foundation.

"The problem is that inside of a home, radon can actually get trapped and can build into higher levels," Bo Cheyne, an environmental health specialist with WDGPH told Craig Norris on CBC KW's The Morning Edition.

"The higher the radon levels and the longer you're exposed, the greater risk of you developing lung cancer later in life."

Why Guelph?

Unfortunately, Cheyne says there is no clear indication as to why Guelph homes seem to have a higher level of radon gas than neighbouring cities.

"It's pretty difficult to predict which home might have a higher level than others," she said. "All the more reason for homeowners in Guelph to test their homes."

So the city of Guelph is trying to reduce the risk. The mitigation program requires all new low-rise homes and additions to be built with construction methods that will minimize radon gas entry.

"If you're moving into a new home in Guelph, in the fall after you move in, the city will follow up with you to do radon testing to confirm those levels are low," said Cheyne.