High levels of hippuric acid in the urine of Thai press workers.

Toluene is an important toxic volatile agent found in many modern industrial processes. Toluene exposure is of particular concern because of the ongoing exposure of thousands of workers in industrial plants and recent research has indicated that toluene/exposure can result in chronic toxicity. The monitoring and control of toluene exposure among at-risk workers is necessary. Urine hippuric acid determination is a helpful test monitoring groups of at-risk workers. In this study, urine samples were obtained from 20 control subjects and 48 press workers from a factory in Bangkok. Each subject gave a specimen of urine; each specimen was analyzed for hippuric acid level by the Ohmori method. The average urine hippuric acid level in the control group was 0.23 +/- 0.15 mg/gCr (range = 0.05 - 0.58 mg/gCr) while that of the experimental group was 0.37 +/- 0.37 mg/gCr (range = 0.06 - 0.18 mg/gCr). A significant higher urine hippuric acid level among the press workers was found (p = 0.03). Based on this study, the prevention of exposure to toluene among high-risk workers is recommended.