In May 1993, the appearance of critically ill patients with unexplained respiratory distress was noted in the Four Corners area formed by New Mexico, Arizona, and Colorado. This epidemic was ultimately linked to a hantavirus, an emerging pathogen. The impact on the emergency department of a new infectious disease with respiratory distress is described. A model is proposed to manage infectious disease disasters. Emerging infections that are important to emergency physicians are discussed. Recommendations that focus on disaster management and prevention of the spread of an unknown pathogen are developed.