During the past 3 decades, definitive evidence has accumulated that secondhand smoke causes serious disease and shortens life span. The recent surgeon general's report on involuntary exposure to tobacco smoke concluded that secondhand smoke causes lung cancer, coronary heart disease, and premature death.1 Legislation that eliminates public smoking will therefore reduce the burden of chronic disease and premature mortality. The workplace, which is a major source of secondhand smoke exposure, is a particularly important target for preventive strategies.