Epidemiologic Investigation
-
An outbreak of neurologic symptoms among patients exposed to an unknown stench in a high school near an industrial complex: an epidemiological investigation
-
Kiook Baek, Seongmin Jo, Chulyong Park, Joon Sakong
-
Epidemiol Health. 2022;44:e2022105. Published online November 9, 2022
-
DOI: https://doi.org/10.4178/epih.e2022105
-
-
Abstract
Summary
PDFSupplementary Material
-
Abstract
OBJECTIVES
Seven students at a high school in Korea visited the emergency room with non-specific neurological symptoms after a stench was noticed during a school entrance ceremony. In relation to this incident, 105 patients visited medical institutions over 5 days. A team of environmental and epidemiological experts was assembled to investigate the incident.
METHODS
Our team of experts participated in the investigation 1 month post-incident. Previously, only air samples had been analyzed. We received results of air samples analyzed by other investigators, medical records of some students, and data from police interviews of patients. Additional investigation and interviews were conducted, and the events were reconstructed in spatial and temporal order.
RESULTS
A cluster of patients was observed on the south side and parts of the north side of the upper floor. A stench like that reported during the incident had been noticed for about 2 years near the school. Students consistently described a similar stench occurring frequently in the vicinity of the school. According to student statements, the odor mainly resembled something burning. The carboxyhemoglobin levels of some students were observed to be >1.5%.
CONCLUSIONS
In the investigation, 2 suspected sources were identified: a science room storing chemicals downstairs from the auditorium and various industrial facilities near the school. Combining the scattered evidence, we considered a toxic puff of gas, perhaps from brief incineration or leakage in a specific area, to be the likely cause of the incident. We describe our approach and the limitations encountered during the investigation.
-
Summary
Korean summary
본 논문은 일개 고등학교에서 원인미상의 악취와 함께 100명 이상의 환자가 발생한 사건에 대한 조사과정을 담은 문헌이다.
본 연구진은 사건 발생 후 약 1달 후에 조사진에 합류하였으며, 발생 당시 환자 분포 점지도 작성, 인근 지역 사업장 및 악취발생 장소 점지도 작성, 사건 전후 시계열적 사건분석, 기상자료, 관계자 인터뷰 자료 분석 등의 역학적 기법을 동원하여 원인을 인근 지역에서 발생한 퍼프 가스의 유입으로 추정하였다.
본 사건의 원인은 결국 미제로 종결되었지만 추후 유사 사례 발생시 본 조사의 방법론을 참고할 수 있을 것이며, 의료진의 조기 개입을 수행하지 못함으로 인한 초기 상세 인터뷰 자료 확보, 생체 시료 수집 등이 이루어지지 못한 본 조사 과정의 한계점을 반면교사로 삼을 수 있을 것이다.
Key Message
This paper presents an investigation of an outbreak of over 100 patients experiencing an unexplained odor in a high school. The research team utilized epidemiological methods, including dot mapping, temporal analysis of events, and interview data analysis. The source of the odor was estimated to be the inflow of puff gas from surrounding areas. Although the toxic puff gas discharge facility was not identified, sharing the experience from this investigation could help with future investigations of similar incidents.