Biological monitoring standards for industrial toluene exposure recommended for South Africa.

Coal combustion is used in many industrial processes in South Africa. The exposure of workers and the absence of international biological monitoring standards for toluene created a problem. A cross-sectional study on 100 workers indicated that the biological threshold for ortho-cresol:creatinine ratio reference value of < 1 mg/g could presently be used as a reference for non-industrial human exposure while the < 2 mg/g rate is for worker exposure in an industrial environment at a coal combustion plant.