Exposure to secondhand smoke, or environmental tobacco smoke ( ETS ), significantly increases the risk of lung cancer and heart disease in nonsmokers, as well as several respiratory illnesses in young children (5). (Secondhand smoke is a combination of the smoke that is released from the end of a burning cigarette and the smoke exhaled from the lungs of smokers.) The U.S. Environmental Protection Agency (EPA), the National Institute of Environmental Health Science’s National Toxicology Program, and the World Health Organization’s International Agency for Research on Cancer (IARC) have all classified secondhand smoke as a known human carcinogen —a category reserved for agents for which there is sufficient scientific evidence that they cause cancer (5, 6, 7). The U.S. EPA has estimated that exposure to secondhand smoke causes about 3,000 lung cancer deaths among nonsmokers and is responsible for up to 300,000 cases of lower respiratory tract infections in children up to 18 months of age in the United States each year (5).