Benzene Exposure among Occupations at Gasoline Service Stations

Abstract

This study aimed to investigate the benzene exposure of workers at gasoline stations among three groups of occupations (fueling workers (n=30), engine oil workers (n=12) and shop operator (n=8) from eight gasoline stations. The biomarker of low benzene exposure (t, t-Muconic acid t,t-MA) was collected from each worker at the end of shift-work for analysis. The results showed that t,t-MA was ranged from 5.76 to 3.019.05 µg/g Cr which was higher than the limit value recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) at 500 µg/g Cr for 30.0%. Fueling workers had t,t-MA ranging from 5.76 to 3,019.05 µg/g Cr which was higher than the recommended limit value at 10%, engine oil worker had t,t-MA ranging from 54.36 to 705.08 µg/g Cr which was higher than the recommended limit value at 10% and shop operators had t,t-MA ranging from 339.49 to 1,717.19 µg/g Cr, which was higher than the recommended value for 10%. When using Wilcoxon signed rank test to analyze the t,t-MA value difference among occupations, the median t,t-MA value of all workers were significant lower than 500 µg/g Cr (P50 = 261.67; 95%CI = 148.4 – 376 µg/g Cr). In comparison among occupations exposed to benzene by using the Wilcoxon rank sum (Mann Whitney) test, it was found that no significant difference of t,t-MA between fueling workers and engine oil workers was observed. However, the statistically significant difference of t,t-MA among fueling workers and engine oil workers was observed when compared to the shop operator.  The results showed that most shop operators had t,t-MA higher than the limit value recommended by ACGIH. Therefore, the health monitoring program on benzene exposure should be done for all occupations involved at gasoline service station and further studies, it should also be focused on factors related to benzene exposure among these three occupations at gasoline station.