In a survey of 370 aluminium potroom workers in western Norway, bronchial responsiveness, lung function, and respiratory symptoms were studied in relation to occupational exposure to air contaminants in the potroom. Increased prevalences of respiratory symptoms, work related asthmatic symptoms, and abnormal lung function were found in subjects exposed to total fluorides above 0.5 mg/m3 when compared with workers exposed to total fluorides at concentrations of less than 0.5 mg/m3. No significant association between bronchial responsiveness and exposure to fluoride was found and the prevalence of respiratory symptoms was independent of the degree of dust exposure. These findings indicate that work related asthmatic symptoms in potroom workers may be related to exposure to fluorides.