OCCUPATIONAL ASTHMA DUE TO CHROME AND NICKEL ELECTROPLATING

Background-Exposure to chromium during electroplating is a recognised though poorly characterised cause of occupational asthma. The first se ries of such patients referred to a specialist occupational lung disea se clinic is reported. Methods-The diagnosis of occupational asthma wa s made from a history of asthma with rest day improvement and confirme d by specific bronchial provocation testing with potassium dichromate and nickel chloride. Results-Seven workers had been exposed to chrome and nickel fumes from electroplating for eight months to six years bef ore asthma developed. One subject, although exposed for 11 years witho ut symptoms, developed asthma after a single severe exposure during a ventilation failure. This was the only subject who had never smoked. T he diagnosis was confirmed by specific bronchial. challenges. Two work ers had isolated immediate reactions, one a late asthmatic reaction, a nd four a dual response following exposure to nebulised potassium dich romate at 1-10 mg/ml. Two of the four subjects were also challenged wi th nebulised nickel chloride at 0.1-10 mg/ml. Two showed isolated late asthmatic reactions, in one at 0.1 mg/ml, where nickel was probably t he primary sensitising agent. Four workers carried out two hourly meas urements of peak expiratory flow over days at and away from work. All were scored as having occupational asthma using OASYS-2. Breathing zon e air monitoring was carried out in 60 workers from four decorative an d two hard chrome plating shops from workers with similar jobs to thos e sensitised. No measurement exceeded the current occupational exposur e standard for chromate or nickel, the mean levels of chromate exposur e for jobs similar to those of the affected workers were 9-15 mu g/m(3 ). Conclusion-Chrome used in electroplating is a potential cause of oc cupational asthma. Sensitivity to chrome in electroplaters may occur i n situations where exposure levels are likely to be within the current exposure standards. There may be cross reactivity with nickel. Inhala tion challenge with nebulised potassium dichromate solution is helpful in making the specific diagnosis where doubt exists.