FORMATION OF HYDROXYL RADICALS AND TOXICITY OF TUNGSTEN-OXIDE FIBERS

Occupational exposure to hard metal dust may cause interstitial pulmon ary fibrosis and asthma. The cause of asthma is well established, wher eas the cause of lung fibrosis is still under debate. Recently, slight ly reduced airborne tunsten oxide fibres, the role of which in hard me tal pneumoconiosis has never been accounted for, were detected in an a ir sample from a hard metal production plant. In this study, the capac ity to generate hydroxyl radicals, toxicity to cultured human lung cel ls and haemolytic activity of tungsten oxide fibres were compared with crocidolite asbestos fibres. The results show (a) that tungsten oxide fibres can generate hydroxyl radicals, and (b) that tunsten oxide fib res were more cytotoxic to human lung cells than was crocidolite, but (c) that the haemolytic activity of tungsten oxide fibres was lower th an for crocidolite.