In a high school in Korea, seven students visited the emergency room with non-specific neurological symptoms after a stench occurred during the entrance ceremony. A total of 105 patients visited the medical center over five days. A team of environmental and epidemiologic experts was assembled to investigate the incident.
MethodsOur team, consist of experts of epidemiology, participated in the investigation one month after the incident. Until then, only air samples were analyzed. We received results on air samples analyzed by other investigators, medical records of some students and police's patient interview data. Additional investigation and interview were performed. The events were reconstructed in spatial and temporal order.
ResultsA cluster of patients were observed in the south and some parts of north sides of the upper floor. A stench similar to that at the time of the incident has been sensed about two years in school area. Students consistently stated that similar stench occurred frequently in the vicinity of the school. According to students' statements, odor pattern was mainly that of something burning. Some students' CO-Hb was observed to be >1.5%.
ConclusionsIn the investigation process, two suspected sources were identified; a science room storing chemicals downstairs of the auditorium, and various industrial facilities located near the school. Combining the scattered evidence, our team considered toxic puff gas, maybe from incineration or leak in a specific area for a short time, was the cause of the incident. We describe our approaching process and the limitations encountered during investigation.