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A cross sectional study was conducted on 513 employees at three hard metal plants: 425 exposed workers (351 men, 74 women) and 88 controls (69 men, 19 women). Cough and sputum were more frequent in workers engaged in "soft powder" and presintering workshops compared with controls (12-5% and 16X5% v 3 5%). Spirometric abnormalities were more frequent among women in sintering and finishing workshops compared with control women (56-8% v 23-8%) and abnormalities of carbon monoxide test were more frequent in exposed groups than in controls; this difference was more pronounced in women (31[4% v 5-6%) than in men (18-5% v 13%). No significant correlation was observed between duration ofexposure and age adjusted lung function tests. Slight abnormalities of chest radiographs (0/1, 1/1 according to ILO classification) were more frequent in exposed men than controls (12-8% v 1-9%) and mostly in soft powder workers. In subjects with abnormal chest radiographs FVC, FEV1 and carbon monoxide indices (fractional uptake of CO or CO transfer index or both) were lower compared with those with normal chest radiographs. Although relatively mild, the clinical, radiological, and functional abnormalities uncovered call for a regular supervision of workers exposed to hard metal dust.The industrial use of hard metal tools began in Germany in 1922. Owing to their hardness and resistance to wear and high temperatures they are used to make cutting tools, drill tips, and armament components. Their qualities are due mainly to tungsten carbide which, with cobalt (Co), constitutes the essential part of this alloy. They are produced according to the powder metallurgy technique in specialised factories in relatively large quantities (in France 300 tons a year at present).About 20 years later, hard metals were suspected of being responsible for bronchopulmonary disorders, first in Germany, then in the other industrialised countries. Despite a certain heterogeneity of the symptoms and signs, the condition progresses towards a diffuse pulmonary fibrosis and leads to severe respiratory insufficiency. Except for sporadic case reports, the frequency and intensity of clinical and functional respiratory disorders which can be observed among a group of workers exposed to hard metal dust are not well known. Thus a cross sectional survey was conducted among a group of 425 workers exposed to hard metal dusts and of 88 controls who worked in three factories.

Objectives-To assess the effect of an occupational exposure to talc dust on respiratory health. The prevalence of dyspnoea also increased after adjustment for smoking categories and age in a logistic regression. The prevalence of small radiological opacities was significantly related to age and to the exposure after adjustment for age and smoking categories. The incidence of new opacities between the two radiographs (11 new opacities with a profusion higher than 01) was significantly related to smoking (10 out of 11 are smokers) but not to the exposure. Conclusion-This study shows an effect of high levels of talc dust both on functional variables and on the prevalence of small radiological images, but provides no clear evidence about the possible effect of present levels of exposure.

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