A follow-up study of airway symptoms and lung function among residents and workers 5.5 years after an oil tank explosion

BACKGROUND Assess if people who lived or worked in an area polluted after an oil tank explosion had persistent respiratory health impairment as compared to a non-exposed population 5.5 years after the event. METHODS A follow-up study 5.5 years after the explosion, 330 persons aged 18-67 years, compared lung function, lung function decline and airway symptoms among exposed persons (residents <6 km from the accident site or working in the industrial harbour at the time of the explosion) with a non-exposed group (residence >20 km away). Also men in the exposed group who had participated in accident related tasks (firefighting or clean-up of pollution) were compared with men who did not. Data were analysed using Poisson regression, adjusted for smoking, occupational exposure, atopy and age. RESULTS Exposed men who had participated in accident related tasks had higher prevalence of lower airway symptoms after 5.5 years (n = 24 [73%]) than non-exposed men (28 [48%]), (adjusted relative risk 1.51 [95% confidence interval 1.07, 2.14]). Among men who participated in accident related tasks FEV1 decline was 48 mL per year, and 12 mL among men who did not (adjusted difference -34 mL per year [-67 mL, -1 mL]), and at follow-up FEV1/FVC ratio was 71.4 and 74.2% respectively, (adjusted difference -3.0% [-6.0, 0.0%]). CONCLUSION Residents and workers had more airway symptoms and impaired lung function 5.5 years after an oil tank explosion, most significant for a group of men engaged in firefighting and clean-up of pollution after the accident. Public health authorities should be aware of long-term consequences after such accidents.