Respiratory Health Effect of Persons Accidentally Expose to High Concentration of Chlorine Gas
Nitipatana Chierakul MD*, Nuttapol Rittayamai MD*, Prachya Passaranon MD*, Charttiwut Chamchod MD**, Bralee Suntiwuth MD***
Affiliation : * Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Department of Occupational Health, Bangkok, Thailand *** Department of Medicine, Rayong Hospital, Rayong, Thailand
Objective : To evaluate the short term and long term respiratory health effects of subjects who accidentally exposed to high
concentration of chlorine gas.
Material and Method: There was an accidental leakage of sodium hypochlorite from an industrial factory in Rayong
province in June 2010. Medical records of those who developed severe symptoms after exposed to high concentration of
chlorine gas were reviewed. Prospective observational study was conducted after hospital discharge by interviewing with
respiratory health questionnaires, physical examination, spirometry, methacholine challenge test, and home peak expiratory
flow (PEF) monitoring at 2, 5 and 8 months after the event.
Results : Among 1,434 persons exposed to chlorine gas, 92 developed severe symptoms required hospital admission and 21
participated in the follow-up study at 2 months there after. Respiratory symptoms were noted in 18 participants. Three most
common symptoms were dyspnea (81%), chest tightness (71%), and cough (67%). Obstructive defect from spirometry was
identified in 2 participants, one of which also had bronchial hyper responsiveness (BHR) compatible with reactive airway
dysfunction syndrome (RADS). Seven participants had abnormal PEF variability. There were 10 and 5 participants left in the
follow-up visit at 5 and 8 months respectively. Two participants had persistent obstructive defect with additional two subjects
were noticed. Those who had BHR and abnormal PEF variability remained unchanged.
Conclusion : Acute exposure to high concentration of chlorine gas causes both significant short and long term respiratory
health effects. Most of the patients although have gradual improvement of respiratory symptoms, but some symptoms remain
persistent. Few patients have lung function impairment lasting for at least 8 months.
Keywords : Chlorine, Respiratory symptoms, Spirometry, Bronchial hyperresponsiveness, Peak expiratory flow variability, Lung function impairment
