Silicosis outside the mines in South Africa has received little legislative or public attention. Between 1972 and 1986 217 such cases were seen at the National Centre for Occupational Health clinic, including 46 cases of progressive massive fibrosis. The relatively high proportion of cases of progressive massive fibrosis (21%), of patients less than or equal to 40 years at diagnosis (21% of blacks) and with exposures of less than or equal to 10 years (18%) indicate high silica exposures in industry. Four industries accounted for 83% of the cases--foundries, ceramics factories, refractories, and ore and stone crushing. Radiologically, readings of a mixture of rounded and irregular opacities were not uncommon (14%). Lymphadenopathy was very uncommon (less than 1%), while pleural thickening other than loss of the costophrenic angle was absent. Prevalences of symptoms, signs and lung function abnormality were high, probably owing to a range of factors other than silicosis. Cases of progressive massive fibrosis had significantly higher prevalences of these clinical abnormalities. When two separate lung function prediction equations were applied to the observed values in these cases, the number that met criteria for 'abnormality' differed. This finding has important implications for compensation. Recommendations include control of silica-using industries and careful occupational history-taking by clinicians.