Secondhand Smoke Make an Appointment Ask a Question Search Conditions Secondhand Smoke (SHS), also called Involuntary Smoking, Passive Smoking, or Environmental Tobacco Smoke (ETS), is a combination of tobacco smoke exhaled by a smoking person as well as the smoke produced by the burning end of the cigarette, cigar or tobacco pipe. SHS contains at least 250 toxic chemicals, including arsenic, formaldehyde, hydrogen cyanide, and radioactive elements. More than 50 of these toxic chemicals can cause cancer. A person standing 20 inches from a burning cigarette may inhale 10 times more of these toxic chemicals than the person smoking the cigarette. No level of SHS exposure is risk-free. Nearly half of the people in the U.S. have biological evidence of SHS exposure. SHS is the number one source of indoor air pollution. Most exposure to tobacco smoke occurs in homes and workplaces. Spending one hour in a smoke-filled room is equal to smoking one cigarette. If you are exposed to SHS, consider taking one of the following steps: Ask your family member, friend, or coworker to quit smoking Ask your family member, friend, or coworker to only smoke outside Ask you employer to ban smoking in your workplace References The health consequences of smoking – 50 years of progress: a report of the Surgeon General. – Atlanta, GA. : U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014. National Toxicology Program. 11th Report on Carcinogens, 2005. Research Triangle Park, NC: U.S. Department of Health and Human Sciences, National Institute of Environmental Health Sciences, 2000. This information has been approved by Amy Lukowski, PsyD (August 2015).