Provincial health officials are advising Nova Scotians to get their homes tested for radon gas, a natural substance that can lead to cancer.

The recommendation comes as Health Canada proposes to lower the acceptable limit for radon from 800 Becquerels per cubic metre to 200.

Radon is a colourless, odourless gas released by the decay of uranium in soil. Long-term exposure to high levels of the radioactive substance can lead to cancer.

A 1997 national survey suggested that radon gas exposure led to the deaths of 1,589 Canadians, said Dr. Robert Strang, a medical officer of health in Nova Scotia.

"Based on the Nova Scotia proportion of the national population … about 40 Nova Scotians died from lung cancer due to radon exposure," Strang said Monday.

All the schools in the province will be tested for radon over the next five years. Schools in the St. Margaret's Bay area that have had radon-related water problems will get priority.

New schools like Citadel High in Halifax are being built with radon vents as a precaution, but older schools may need expensive refits.

Testing of homes urged

A radiation consultant said radon exposure is not always harmful.

"It's with us everywhere, as we walk the streets, it's there," said Pat Wall, of the Department of Environment and Labour. "Where it is a danger is when it enters an enclosed space."

That's why people need to test their homes, he said, adding the average cost is between $50 and $100.

Lewis Brill, president of the Lung Association of Nova Scotia, would like to see the province pick up the tab for those who can't afford it.

"I certainly think cost could be a factor for low-income people, and I think this is something we would ask the government to take a look at," he said.

Cost should not be a barrier when it comes to protecting health, Brill said.