Canada needs stricter radon exposure guidelines, an advisory panel recommends.

Radon is a colourless, odourless gas released by the decay of uranium in soil.

The radioactive gas attaches itself to dust that people breathe in.

Radon is the second leading cause of lung cancer after smoking. About 1,900 deaths were attributed to the gas in 2005, panellists said.

The report's authors include experts from federal and provincial health ministries across the country.

Canadians are exposed to radon seeping into basements through cracks and holes in foundations.

The cancer risk is not imminent, but is caused by exposure over decades, Michael Grey of the Canadian Radiation Protection Agency said Wednesday.

Radon higher in uranium cities

Grey said radon is everywhere, but is higher in areas with more uranium, such as Winnipeg and Ottawa.

People can hire companies to perform a test to detect the gas or buy do-it-yourself tests.

But the experts concluded the current Canadian limit, 800 becquerels per cubic metre of air, is too high.

A becquerel is a measure of radioactive decay.

The panel recommends using the limit set in Britain, Sweden and Norway: 200 becquerels per cubic metre.

Under the lower standard, homes in danger would have to undergo renovations, such as changes to ventilation, Grey said.

Canada's current radon exposure levels are based on guidelines that are 20 years old, using radon exposure for uranium miners, rather than household exposure levels.