Occupational asthma is the principal respiratory health problem within the primary aluminium industry. Current evidence indicates that it is irritant induced and due to occupational exposure to the inhalation of gaseous or particulate fluoride compounds. Following transfer from the occupational exposure of those who develop asthma, there is commonly symptomatic improvement. A programme of compulsory respiratory protection, progressive engineering improvements and of regular screening of potroom workers aimed at early detection, and the transfer of asthmatic workers from that environment has resulted not only in improvement of asthmatic symptoms among them, but also in the majority of an improvement in bronchial responsiveness as assessed by methacholine inhalation. The majority of studies indicate a slightly increased prevalence of symptoms of chronic bronchitis and of chronic obstructive pulmonary disease among workers in carbon bake areas, although tobacco smoking has a greater and additive effect. Only a trivial number of clinical cases of pulmonary fibrosis ascribed to aluminium compounds has been reported. Particle size limits smelter grade primary alumina reaching the alveoli of the lung.