Secondhand smoke is composed of sidestream smoke (the smoke released from the burning end of a cigarette) and exhaled mainstream smoke (the smoke exhaled by the smoker). Secondhand smoke contains more than 50 cancer-causing chemicals. Secondhand smoke has been found to cause cancer by the EPA and has been classified as a Class A carcinogen.
The Surgeon General has concluded:
- There is no risk-free level of exposure to secondhand smoke: even small amounts of secondhand smoke exposure can be harmful to people's health.
- Many millions of Americans continue to be exposed to secondhand smoke.
- A smoke-free environment is the only way to fully protect nonsmokers from the dangers of secondhand smoke. Separating smokers from nonsmokers, cleaning the air, and ventilating buildings cannot eliminate exposure of nonsmokers to secondhand smoke.
Information taken directly from The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General.