An exploratory study of manganese exposure to welders.

Sixty welders (20 each from Plants A, B, and C) and 20 control subjects were investigated for the possible occurrence of manganese poisoning among welders exposed to the welding fumes containing this metal. Ten, 9, and 5 welders from Plants B, C, and A, respectively, were diagnosed as suspected cases of early manganese poisoning. The diagnosis was based on the proof of overexposure to manganese by the findings of increased urinary levels of this metal, signs of early neurological involvement, and increased contents of serum calcium. These results are discussed in relation to the manganese concentration in the air around the welder's breathing zones.