U.S. Surgeon General Dr. Richard H. Carmona issued a comprehensive scientific report today that concludes there is no risk-free level of exposure to secondhand smoke. This finding is a major public health concern since nearly half of all nonsmoking Americans are still regularly exposed to secondhand smoke.

According to the report, nonsmokers exposed to secondhand smoke at home or work have a 25 to 30 percent increased risk of developing heart disease and a 20 to 30 percent increased risk for lung cancer. The report, The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General, finds that even brief secondhand smoke exposure can cause immediate harm to people's health. The report notes that the only way to fully protect nonsmokers from the dangerous chemicals in secondhand smoke is to eliminate smoking indoors.

"The good news is that, unlike some public health hazards, secondhand smoke exposure is easily prevented," Dr. Carmona said. "Smoke-free indoor environments are proven, simple approaches that prevent exposure and harm." The Surgeon General noted that levels of cotinine - a biological marker for secondhand smoke exposure - measured in nonsmokers have fallen by 70 percent since the late 1980s, and the proportion of nonsmokers with detectable cotinine levels has been halved from 88 percent 1988 to 1991 to 43 percent 2001 to 2002.

Dr. Carmona emphasized, however, that sustained efforts are required to protect the more than 126 million Americans who continue to be regularly exposed to secondhand smoke in the home, at work, and in other enclosed spaces, including automobiles.