A follow-up comparison of blood lead levels between foreign and native workers of battery manufacturing in Taiwan

Foreign workers employed in industries in Taiwan have been found at elevated risk of injuries. Less well known is whether the elevated risk persists in chemical exposure such as lead exposure at battery manufacturing. A cohort of 70 Thai workers and 55 native workers employed at a battery plant were followed up, after an education of job safety, from 2000 until 2002. This study compared the change of blood lead levels (BLLs) between these two groups of workers. With informed consent, BLLs were measured annually for participants and compared. The average baseline BLLs were approximately at similarly high levels between Thai workers and native workers with means ± standard deviations of 36.9 ± 16.4 and 36.2 ± 12.4 μg/dl, respectively (p = 0.79). At the end of 2002, the average concentration was higher in Thai workers than in native workers. Using mixed models, Thai workers had an average of 5.95 μg/dl increase in BLLs over native workers during the 3-year study. Further measurements revealed that the average BLL for workers in the assembly department was 3.57 ± 1.83 μg/dl in excess, compared with workers in the plate engineering department. Thai workers were more likely to drink alcohol but less likely to wear gloves at work and wash hands before meals. The BLL disparities between Thai workers and native workers can partly be explained by differences in risk-taking behaviors. Higher BLLs in Thai workers suggest the need of language appropriate health education to improve their personal hygiene. Workplace smoking ceasing program may be needed both in Thai and native workers.