A cross-sectional survey of 2404 employees in three alumina refineries was performed in 1996. The aims of this study were to investigate associations between respiratory symptoms and lung function and cumulative quantitative workplace exposure to alumina and bauxite dust, as well as recent workplace exposure to caustic mist. All participants answered questions about respiratory symptoms and the relationship of those symptoms to work, as well as having spirometry and providing a complete job history. The job histories were combined with a task exposure matrix for bauxite and alumina dust. The current job was also assigned a semiquantitative exposure to caustic mist. Prevalence ratios (PR) and 95% confidence intervals (CI) for symptoms were calculated for each exposure. Subjects in the highest group of current caustic exposure reported increased prevalence of work related wheeze (PR=1.8 95% Cl 1.0-3.1) and rhinitis (PR=1.6 95% Cl 1.1-2.4) but did not have measurable changes in lung function. Alumina exposure was associated with minor increases in reporting of work related wheeze and rhinitis but no changes in lung function. Bauxite exposure at the levels experienced in these alumina refineries was not associated with either symptoms or lung function changes.