A study of benzene exposure versus urinary phenol levels.

On the job benzene vapor exposures of less than 5 ppm were measured concurrent with the 24 hour collection of urine from 52 employees. Urinary phenol levels of the collective study group, measured as either concentration or weight, showed a positive statistically significant correlation with benzene exposure. However, due to variances in individual baseline phenaol levels, determination of benzene exposure at these low concentrations is relatively weak. Since baseline phenol concentrations exist over a range of values, adjustment for a single value of each individual's baseline did not improve correlation for the collective study group.