The draft report addresses the weight of evidence on the potential associations between passive smoking or Environmental Tobacco Smoke (ETS) and (1) lung cancer in nonsmoking adults, and (2) noncancer respiratory disorders, primarily in children. With respect to lung cancer, the draft report concludes that (1) ETS is causally associated with lung cancer in nonsmoking adults and is an EPA Group A (known human) carcinogen, and (2) approximately 3,000 lung cancer deaths per year among nonsmokers of both sexes in the United States are attributable to ETS. With respect to noncancer respiratory effects, the report concludes that ETS exposure to children from parental smoking is causally associated with (1) respiratory symptoms of irritation (cough, sputum, and wheeze); (2) middle ear effusion; (3) reduced lung function; (4) lower respiratory tract infections (LRIs), particularly in infants; and (5) additional episodes and increased severity of asthma in asthmatic children. The evidence also suggests that ETS exposure induces asthma in previously asymptomatic children. In addition, passive smoking causes some respiratory discomfort and reduced lung function in adults. The report estimates that ETS exposure contributes 150,000 to 300,000 LRIs annually in children under 18 months, resulting in 7,500 to 15,000 hospitalizations, and 8,000 to 26,000 new cases of asthma in previously asymptomatic children, as well as aggravating symptoms in approximately 20% of asthmatic children.