[An epidemiologic study on pulmonary fibrosis caused by hard alloy dust]

A cross-sectional study, with 1,237 employees solely exposed to hard alloy dust and 502 controls in four hard metal works and two tool and grinder manufacturers in China, was conducted. Results showed prevalence of symptoms of respiratory system, and abnormalities in lung function and serum level of ceruloplasmin and urine cobalt content in exposed group were significantly higher than those in controls. Eight cases of pneumoconiosis were detected by chest X-ray films with a prevalence of 0.65% and an average length of employment in dust environment of 25.2 years. It suggested hard alloy dust could cause pulmonary fibrosis and pneumoconiosis in exposed workers.