To study 165 workers in Zx factory and Vinh Phu battery jont stock company, workers were divided two groups which base blood lead level. Group I: (the blood lead level or 10 ug/dl), the blood lead level in group II has a large change. Activity of SOD, the concentration of MDA in group II increase compared with group I (p0,001)
GPx and TAS decrease compared with group I (p0,001). SOD, MDA in group II increase in accordance with age and length of service while GPx and TAS in group II decrease when age and length of service increase.