http://www.surgeongeneral.gov/library/secondhandsmoke/
Office of the Surgeon General, U.S. Department of Health and Human Services
U.S. Surgeon General Richard H. Carmona issued a comprehensive scientific report which concludes that there is no risk-free level of exposure to secondhand smoke. Nonsmokers exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25 to 30 percent and lung cancer by 20 to 30 percent. The finding is of major public health concern due to the fact that nearly half of all nonsmoking Americans are still regularly exposed to secondhand smoke. This page links to the report findings, including information on the dangers of secondhand smoke and steps people can take to protect themselves.