Abuse of nitrous oxide (N2O) while on the job caused at least 11 deaths in 1984 to 1987, as found in investigations by the Occupational Safety and Health Administration and in reports to the Consumer Product Safety Commission. Although nitrous oxide has had a reputation as a "clean and safe" analgesic and anesthetic, the possibility of asphyxiation by inhalation is not widely recognized, and there are no requirements for warning labels on nonmedical sources of N2O. The 11 deaths involved recreational inhalation of N2O by young male employees from tanks or cylinders normally used for legitimate business purposes. In six cases, the victims worked in food serving establishments and inhaled N2O that was used to power whipped cream dispensers. Commercial users of N2O, particularly in the restaurant industry, should be aware of this hazard. Warning labels for N2O sources and tighter control over supplies are warranted.