The threat of a severe infectious disease outbreak resembling the influenza pandemic in 1918 or a large-scale bioterrorist attack on the citizens of the United States compels us to prepare for the unthinkable. Those of us who are hospital engineers and operators are obligated to prepare for a range of scenarios in which large numbers of victims seek health care on an urgent basis. (1) Outbreaks may be relatively small, straining but not overwhelming our operational capacities. Or, the next pandemic may be unlike anything seen in recent history: an outbreak so severe it greatly stretches and eventually overburdens nearly every aspect of our health-care delivery and public health systems on a national or global scale. We simply don't know which one awaits us in the future.