A large quantity of white gas containing titanium dioxide and hydrogen chloride was generated unexpectedly during an experiment in a chemical laboratory. Fourteen students and staff complained of nausea, dyspnea, or respiratory irritation immediately after inhaling the gas. On arrival at Saint Luke's International Hospital, more than half of the patients presented with low-grade fever. Symptoms spontaneously resolved soon after admission, although the low-grade fever persisted until the following morning. Low-grade fever after inhalation exposure is not explicable by hydrogen chloride inhalation and therefore appeared to be caused by titanium dioxide inhalation, manifesting as metal fume fever. Titanium dioxide is thought to have no remarkable human toxicity and is considered to be safe clinically. To our knowledge, this is the first report of titanium dioxide inhalation as the potential cause of metal fume fever in humans. Correlations between the degree of fever and quantity and concentration of inhaled titanium dioxide remain to be determined.