Since the late 1970s, the dangers associated with passive (involuntary) smoking have been widely debated. While research throughout the world has produced findings showing sidestream smoke to be harmful and possibly deadly to nonsmokers, an equal number of studies have indicated that the harms have been overstated or misclassified or that they are nonexistent. Those debates have culminated in a report sponsored by the Environmental Protection Agency and other federal agencies. The report concludes that second-hand cigarette smoke kills 53,000 nonsmokers a year and is a major cause of indoor air pollution. This article identifies the major medical and economic issues in the debate on side-stream smoke. It affirms the federal government's position on the need to create more smoke-free environments and impose stronger smoking restrictions nationwide.