Pneumoconiosis and lung function in a group of kaolin workers.

In June 1981, 65 current and former workers at a kaolin mine and mill were examined by chest radiography, spirometry, and a questionnaire. Five (13%) of 39 current workers and 3 (19%) of 16 former workers with 5 yr or more of exposure had radiographic evidence of pneumoconiosis. Among the 8 workers with pneumoconiosis, conglomerate upper lobe lesions were present in one half. No pneumoconiosis was observed among 8 current workers with less than 5 yr of exposure. Lung function testing showed significant reductions (p less than 0.05) in FVC, FEV1, and peak flow rate in kaolin workers compared with that in a control group. Environmental sampling during the testing period showed airborne dust to be composed of kaolinite (96%) and titanium dioxide (4%). Additional controlled epidemiologic studies among kaolin workers are needed to generate reliable prevalence data for pneumoconiosis and to assess the impact of dust exposure on pulmonary function.