Twenty-four factories registered at the Ministry of Labor as factories using or producing cadmium in 1991 were investigated to know the present state of occupational exposure to cadmium in 1992.
Nine factories among 24 stopped using or changed to other substances and 1 factory didn't produce any more, but delivered into other factories through imports. Therefore, only 14 factories were producing or using cadmium. But, alloying materials
were
supplied to about 20 and more factories, however, they couldn't be investigated because of limited information.
Three factories had less than 50 workers were 3, 6 had 50-300 and 5 had more than 300. About 167 workers were exposed to cadmium.
According to the classification by process, there were 4 alloy processes, 2 refinary, 2 elctroplating, 2 dry cell making, 1 industrial battery making, 1 duplicator drum making, 1 recycling of battery and 1 copper refinary. 8 factories used metal
cadmium, 3 cadmium oxide, 2 cadmium sulfide, and 1 cadmium hyroxide. One factory was importing cadmium stearates only and supplying them to the PVC making factories. The amount of metal cadmium producing in 2 refinary factories was about 50-65
ton
per
month. The other cadmium compounds were imported.
According to exposure level of cadmium in air of the 10 factories examined, each factory could be divided into high, moderate and low exposure groups. 1 battery recycling factory and 3 alloy factories were in the high exposure group and their
mean
air
concentrations were 0.06679, 0.05481, 0.02492, and 0.003 mg/m*, respectively. Refinary and industrial battery making factories were in the middle exposure group and their mean air concentrations were 0.00773 and 0.00613 mg/m*, respectively.
Finally, low
exposure group were copper smelting, dry cell case making, duplicator drum making and electroplating factory and their mean air concentrations were 0.00096, 0.00071, 0.00057 and 0.00054 mg/m* respectively.
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