臺灣地區錳鋼及矽錳鋼製造工廠勞工錳暴露追蹤調查研究

A Follow-up Study on Manganese Exposure at Ferro-manganese Alloy Manufacturing Plants in Taiwan

錳為鋼鐵等工業的重要原料之一，1985年國內一錳鋼製造工廠發現多位疑似慢性錳中毒案例。本研究分別於1989年、1992年、1995年三次追蹤調查國內該類作業場所勞工暴露與環境改善成效，並提供事業單位通風設施改善輔導，訂定作業規範與職業衛生管理計畫，加強勞工安全教育訓練與危害宣導教育。1985年案發當時勞工錳暴露濃度為28.8 mg/m3。1986年第一次工程改善後錳暴露濃 度降為4.4 mg/m3。1989年國內第一次追蹤調查，勞工錳暴露濃度再度降低為 0.43 mg/m3。1992年第二次追蹤調查，勞工之錳暴露濃度繼績降為0.041 mg/m3。1995年更改新型密閉式熔爐後，勞工之錳暴露濃度再降為0.004 mg/m3，遠低於法令規定之容許濃度l mg/m3。從勞工工作區域分析，發現直接暴露群之勞工暴露濃度較間接暴露群高，後者又較背景暴露群勞工高；至於出鐵水尖峰期間勞工暴露濃度則未顯著高於非尖峰暴露時間：再分析勞工工作樓層與錳濃度之間的關係，亦顯示樓層愈高，錳暴露濃度呈現愈高的傾向。

Manganese is an important raw material used in industries such as steel-producing in Taiwan. In 1985, several cases of chronic manganese intoxication were discovered among workers in a ferro-manganese alloy manufacturing plant. The government has conducted longitudinal exposure and health hazard follow-up studies in 1989, 1992 and 1995. Assistances such as engineering control, techniques, work practice improvement, occupational health management, and the necessary safety and health information and training were provided. The mean manganese concentration was over 28.8 mg/m3 when the cases were first reported. It fell to 4.4 mg/m3 in 1986 after the initial improvement. In the first follow-up study in 1989, it was lowered to 0.43 mg/m3. In the next follow-up study in 1992, it was further reduced to 0.041 mg/m3. In 1995 after the new enclosed furnace was installed, the exposure concentration was again lowered to 0.004 mg/m3, which was far below the Permissible Exposure Limit of 1 mg/m3. The exposure of directly exposed group is significantly higher than that of indirectly exposed group, which is also significantly higher than that of the background group. There is no difference in exposure between the peak and non-peak working hours. The exposure level increased significantly with theheight of the working locations.