Truth hurts--hard lessons from Australia's largest mass casualty exercise with contaminated patients.

In response to the increasing threat of a mass casualty incident involving chemical, biological or radiological agents, and concern over the preparedness of our hospital system to cope with patients from such an incident, we conducted the largest hospital-based field exercise involving contaminated patients that has been held in Australia. In the present paper, we outline the background to, and methodology of, Exercise Supreme Truth, and the efforts made to increase its realism. We focus our discussion on three issues highlighted by the exercise, which we believe have enormous implications for the development of hospital chemical, biological or radiological plans and the likelihood of their success--hospital security, crowd control and decontamination.