Exposure to oil mist used in metal work sometimes gives symptoms from skin and airways. This study was performed to evaluate histological and functional respiratory tract disorders. Six male lathe workers aged 31-64 years exposed to oil mist for 4-29 years were examined and compared with matched controls. The investigation included case history, ENT examination, nasal mucociliary function, routine blood tests, IgE, RAST, X-ray of sinus and lungs and biopsy of the nasal mucosa. The mucociliary test showed no difference between the groups. However, all 6 exposed workers had pathological histology findings in the nasal mucosa including lack of cilia, basal cell hyperplasia, goblet cell hyperplasia, squamous metaplasia and subepithelial hyalinization. The biopsies from the controls were mainly normal. The remainder of the investigations revealed no pathology. The study shows that exposure to oil mist--even below the permitted threshold limit--may cause airway symptoms and histological signs comparable to a premature ageing.