Multiple deaths from argon contamination of hospital oxygen supply

During the course of routine hospital surgical procedures, three patients lapsed into hypoxic cyanosis. Two expired immediately, another after four days of coma. Investigation of the hospital's central liquid oxygen tank revealed that it had been refilled recently and was labelled both "oxygen" and "argon." Mass spectrometric analysis of gas sampled from the questioned tank revealed a predominance of argon. A discussion of the sampling technique, method of analysis, role of the criminalist, and causes of this accident is presented.