Potential Airwav Obstruction 7 years Following Exposure to Chlorine

摘要

Background: On January 6, 2005 there was a train derailment which released~54,430 kg of chlorine into the town of Graniteville, SC, USA, population～7,000. Aim: To assess long-term pulmonary health effects of a single high-concentration exposure to chlorine gas. Methods: Since summer 2012 diagnostic pulmonary function tests with single breath carbon monoxide diffusing capacity(DLCO) are being provided to 600 former Graniteville cotton mill workers to assess long-term health consequences of chlorine exposure(N to-date= 83). Demographic information, respiratory symptoms, exposure and smoking history abstracted from occupational records before the chlorine release are being linked to prospective health assessments. Preliminary data for participants whose lung volumes and DLCOs met ATS criteria were included (lung volumes: n=65,19/46 exposed/unexposed, DLCO: n=72, 20/52 exposed/ unexposed). Mean percent predicted measures for pulmonary function parameters and DLCO adjusted for hemoglobin were compared between exposed and unexposed millworkers using Fisher exact and T-test. Results: We found a significant increase in percent predicted residual volume (RV) and total lung capacity (TLC) in exposed millworkers (p=0.02). The proportion of millworkers with lower predicted FEV1/FVC ratio was significantly higher in exposed than in unexposed (p＜.0001). There were 7/19(37%) exposed who have FEV1/FVC ratio less than 70% of predicted as compared to 3/46(6.5%) unexposed and 10/19(53%) exposed who had FEV1/FVC ratio less than 75% of predicted as compared to 9/46(20%) unexposed. Four of 20 exposed (20%) showed a moderate decrease in DLCO as compared to 6 of 52 unexposed (11%). Conclusion: Our preliminary findings suggested that inhalation of high concentration chlorine increased RV and TLC and decreased FEV1/FVC ratio 7 years after exposure, indicators of airway obstruction or destroyed alveolar septa leading to emphysema like changes. Further research is needed to discern the mechanism behind these changes.