Involuntary exposure to environmental tobacco smoke (ETS) is a serious and entirely preventable public health hazard. It has become clear that ETS adversely affects the health of all who breathe its toxins. Independent of active smoking, ETS exposure is a modifiable risk factor for chronic obstructive pulmonary disease. The expanding body of research presented in this article provides evidence that the damaging consequences of ETS reach far beyond the lungs. Having been determined the third leading cause of preventable death in this country, this is a problem that must be addressed aggressively.