Radon: it's an unwelcome house guest but it's also a house guest you can get rid of.

Radon detector

Radon detection kits can be purchased online or at home improvement stores. (CBC)

Radon is a radioactive gas that is formed naturally by the breakdown of uranium in soil, rock and water. It is slowly released from the ground, water and some building materials and can seep into your home through cracks in the foundation or basement.

High levels of radon in indoor air are linked to an increased lifetime risk of developing lung cancer. The risk is higher for smokers. On average, 16 per cent of lung cancer deaths in Canada can be attributed to radon exposure. Radon is the second leading cause of lung cancer, after smoking, Health Canada says.

Radon is odourless and colourless, so you have no way of knowing it is in your home unless you use a radon detector. You can buy radon detection kits online or at home improvement stores. You will likely have to set it up in your basement for several months before sending it to a lab for analysis. Health Canada recommends you test your house for radon for a minimum of three months. The best time to check for radon is during the winter months, when windows and doors are kept closed.

If it turns out you've got a high level of radon in your home, follow the steps outlined in this video to remove the threat. But be prepared to dig deep into your wallet: you may have to hire a contractor and it could cost anywhere from $500 to $3,000 to prevent radon from seeping into your home.