[Condition of the nasal and pharyngeal mucosa in workers exposed to titanium dioxide dust].

Fifty-eight workers occupationally exposed to titanium dioxide dusts underwent repeated laryngological and cytological examinations of their nasal mucous membrane smears. The clinical examination showed chronic, whether simple or atrophic, rhinitis (77 per cent) and pharyngitis (50 per cent). The cytological test revealed, in all smears, metaplasia of the respiratory epithelium, towards squamous epithelium. Both the rate of catarrhal changes and the degree of epithelial metaplasia have been found to vary with the duration of daily exposure. The changes in epithelium and nasal mucous membrane occurred after six months' exposure.