Washington ? Secondhand smoke dramatically increases the risk of heart disease and lung cancer in nonsmokers and can only be controlled by making indoor spaces smoke-free, according to a comprehensive report issued Tuesday by U.S. Surgeon General Richard Carmona.

“The health effects of secondhand smoke exposure are more pervasive than we previously thought,” Carmona said. “The scientific evidence is now indisputable: secondhand smoke is not a mere annoyance. It is a serious health hazard that can lead to disease and premature death in children and nonsmoking adults.”

According to the report, the government’s most detailed statement ever on secondhand smoke, exposure to smoke at home or work increases the nonsmokers’ risk of developing heart disease by 25 to 30 percent and lung cancer by 20 to 30 percent. It is especially dangerous for children living with smokers and is known to cause sudden infant death syndrome, respiratory problems, ear infections and asthma attacks in infants and children.

The report – which was applauded and embraced by public-health and tobacco-control advocates – found that nearly half of all nonsmoking Americans are still regularly exposed to smoke from others. It concludes that any exposure to secondhand smoke is a risk to nonsmokers, and as a result the only way to protect nonsmokers is to eliminate indoor smoking.

“Restrictions on smoking can control exposures effectively, but technical approaches involving air cleaning or a greater exchange of indoor with outdoor air cannot,” the report says. “Consequently, nonsmokers 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.”

The report represents the strongest statement about smoking and tobacco control to come out during the Bush administration – which received millions in campaign donations from the tobacco industry.

The administration has been neutral or negative about two major tobacco control initiatives – proposals to grant the Food and Drug Administration authority to regulate tobacco, and enacting the World Health Organization global treaty on tobacco.

The tobacco industry has been somewhat divided on the dangers of secondhand smoke, with R.J. Reynolds Tobacco Co. saying that the science remains inconclusive and Philip Morris USA generally willing to accept public-health advocates’ conclusions. All the companies, however, were accused by the U.S. Justice Department of conspiring to undercut the scientific consensus on secondhand smoke, and that charge remains part of the department’s lawsuit against them.