Respiratory symptoms and lung function in two prebake aluminum smelters

Background: Respiratory symptoms are known to occur in some aluminum smelter employees working in the potroom department but little is known about the respiratory health of employees in other departments. Methods: This cross-sectional study examined the prevalence of work-related respiratory symptoms and levels of lung function in different departments of two aluminum smelters compared to administration employees. Multiple logistic regression was performed with each of four work-related symptoms as outcomes and multiple linear regressions were performed with FEV₁ and FVC as outcomes. Results: There were 1,529 male participants in the two smelters representing a response rate of 89.6%. After adjusting for age and smoking, work-related respiratory symptoms were reported significantly more often among the ingot mill, anode, and potroom groups in Smelter A. In Smelter B, ingot employees were more likely to report work-related wheeze and potroom employees were more likely to report work-related rhinitis. Symptoms tended to increase with increasing time in the potrooms but were more likely to occur in new employees in the ingot mill and anode process groups. After adjusting for age, height, and smoking, there were no significant differences between the process groups for either FEV₁ or FVC at Smelter A, and at Smelter B potroom employees had slightly greater FEV₁ and FVC than the administration employees. Conclusions: Work-related respiratory symptoms among aluminum smelter workers are not reported only by potroom employees but also by ingot mill and anode employees.