Only smoke-free buildings and public places can protect people from deadly second-hand smoke, the U.S. surgeon general said Tuesday.

"The scientific evidence is now indisputable: second-hand smoke is not a mere annoyance," Surgeon-General Richard Carmona said at a news conference.

"It is a serious health hazard that can lead to disease and premature death in children and non-smoking adults."

No level of exposure to drifting smoke is risk-free, said the report, which compiles research on second-hand smoke to guide policy-makers, health professionals and the public.

"Non-smokers need protection through the restriction of smoking in public places and workplaces and by a voluntary adherence to policies at home, particularly to eliminate exposures of children," Carmona wrote.

On the heels of Tuesday's report, Canadian health and labour groups called on the federal minister of labour to legislate protection from second-hand smoke.

"The only federal law governing smoking in the workplace, the 1989 Non-Smokers' Health Act, is now badly out of date and needs to be replaced with a complete ban on smoking in all workplaces under federal jurisdiction — with no ifs, ands or butts," Neil Collishaw, research director at Physicians for a Smoke-Free Canada, one of the groups seeking the change, wrote in a statement.

Several Canadian provinces have passed laws banning smoking in all workplaces, but people working for the federal government, banks, telecommunications or other federally regulated sectors aren't covered.

The U.S. report also concludes:

• Eliminating smoking in indoor spaces fully protects non-smokers from exposure to second-hand smoke, but designated smoking areas with ventilation systems don't eliminate exposure.  
• Brief exposure to second-hand smoke threatens people at high risk of heart disease, because smoke acts so quickly on arteries.
• Living with a smoker increases a non-smoker's risk of lung cancer and heart disease by up to 30 per cent.

Allegations of a cover up  

The report said the tobacco industry has tried to cover up scientific findings on second-hand smoke.

The tobacco industry calls smoking a personal choice.

"It seems unlikely that second-hand smoke presents any significant harm to otherwise healthy nonsmoking adults," Reynolds American Inc.'s R.J. Reynolds Tobacco unit said in a statement on its website.

"Given the extensive smoking bans and restrictions that have already been enacted, non-smokers can easily avoid exposure to second-hand smoke."

In 1964, a surgeon general's report declared second-hand smoke could cause lung cancer in non-smokers. The report led to mandatory cigarette warnings and  advertising restrictions.