The high performance chromatographic method was used to measure the muconic acid concentrations in urine samples collected from 69 workers exposed to benzene and 155 non-exposed workers.

The time weighted average benzene concentrations in breathing zone of workers were also determined. The physical examination and blood counts (hemoglobin, hematocrit, red blood cell, and white blood cell) were made for both workers exposed to benzene and control group.

The results are as follows;

1. The geometric mean of airborne benzene concentrations for all workers was 2.0ppm (0.1-56.9ppm). The mean airborne benzene concentration of workers in adhesive tape manufacturing industry was 12.2ppm (8.3-56.9ppm), which was the highest by type of industry.

2. The geometric mean concentration of muconic acid in urine from male workers exposed to benzene was 3.9 mg/l (0.8-40.8 mg/l), which was significantly higher than that of non-exposed workers. The highest muconic acid concentration was indicated in the workers at the adhesive tape manufacturing industry.

3. There was a significant difference between the mean concentration of muconic acid of workers exposed to airborne benzene concentration of 5-10 pm and that of workers exposed to concentrations below 5 ppm. The urinary muconic acid concentration were correlated with airborne benzene concentration for workers (r=0.85). However there was no significant correlation between urinary phenol concentrations and airborne benzene concentrations.

4. The correlation coefficients between the urinary muconic acid concentration and airborne benzene concentration, urinary phenol concentration, exposure dose(airborne benzene concentration x work duration) and white blood cell were 0.85, 0.74, 0.63 and -0.33, respectively.