Some locations where radon can enter homes. (Associated Press)

Manitoba has the highest percentage of homes testing above guidelines for radon, a cancer-causing radioactive gas.

Scientists now say radon poses more of a risk than they first thought.

They believe 16 per cent of all lung cancer deaths are caused by radon, up from 10 per cent.

Homeowners can test their homes for $50 but removing it can cost $3,000.

Winnipeg parent Beth Gillespie says it's worth it.

"I mean, I wouldn't want to stay in my house if I knew that there was a good chance that you would end up sick from living in your home," she said.

"How could you feel comfortable living in your home knowing that you could potentially die?"

Read Health Canada's national survey of radon concentrations in homes