An Outbreak of Carbon Monoxide Poisoning in Yamagata Prefecture Following the Great East Japan Earthquake

Background: In the aftermath of the Great East Japan Earthquake, most of the areas in Yamagata prefecture experienced a serious power failure lasting for approximately 24 hours. A number of households were subsequently poisoned with carbon monoxide (CO) due to various causes. In this study, we conducted a survey of CO poisoning during the disaster. Methods: A questionnaire regarding CO poisoning associated with the disaster was sent to 37 emergency hospitals in Yamagata prefecture. Results: A total of 51 patients were treated for unintentional CO poisoning in 7 hospitals (hyperbaric oxygen chambers were present in 3 of the hospitals). The patients (18 men, 33 women) ranged in age from 0 to 90 years. The source of CO exposure was charcoal briquettes (23 cases; 45%), gasoline-powered electric generators (18 cases; 35%), electric generators together with oil stoves (8 cases; 16%), oil stoves (1 cases; 2%), and automobile exhaust (1 cases; 2%). Blood carboxyhemoglobin levels ranged from 0.5% to 41.6% in 49 cases. Of these, 41 patients were treated by normobaric oxygen therapy, while one was intubated for artificial respiration. Additionally, 5 patients (10%) were treated by hyperbaric oxygen therapy, and 3 patients (6%) experienced delayed neuropsychiatric sequelae. Conclusion: CO sources included gasoline-powered electric generators and charcoal briquettes during the disaster. Storm-related CO poisoning is well recognized as a disaster-associated accident in the United States, but not in Japan. We emphasize that public education is needed to make people aware of the dangers of CO poisoning after a disaster. In addition, a pulse CO-oximeter should be set up in hospitals.