Abstract
Aim: The aim of this study was to assess benzene exposure of workers assigned to various units of the coke plant in the Annaba steel complex. Method: This cross-sectional study compares the workers assigned to units with a risk of benzene exposure (laboratory, gas and byproduct treatment unit, and the coke oven battery) with security officers at the steel complex, who are not exposed. It was conducted in December 2004: i) Environmental measures: 24 ambient air samples were taken in various work stations in all three units to measure benzene; ii) Biological monitoring: urine samples from workers, taken after an 8-h work shift following 2 days of rest, were used to assay concentrations of phenol and trans, trans-muconic acid. Results: i) Environment: the average benzene concentration in the coke plant is 7 times higher than the regulatory level (1 ppm = 3.2 mg/m(3)) - 10 times higher in the laboratory and 7 times higher in the gas and byproduct treatment unit; ii) Biological monitoring confirmed benzene exposure: the average urinary phenol concentration at end-of-shift was 42.4 mg/g creatinine in exposed workers and 29 mg/g creatinine in unexposed controls, and the mean trans, trans-muconic acid concentration was 5.77 mg/g creatinine in the exposed workers and 0.36 mg/g creatinine in controls. Conclusion: These results confirm benzene exposure in the various units of the coke plant. Plant industrial hygienists must direct their efforts towards the two units at risk in the coke plant: the laboratory and the gas and byproduct treatment unit.