[Urinary excretion of hippuric acid in workers exposed to toluene. Recommendation for a group biological standard (mac) (author's transl].

Four groups of workers of the rotogravure, shoe and plastic industries, all exposed to toluene, were studied by the authors. Hippuric acid was measured by a colorimetric method, on urines collected at the end of the work shift. From the obtained results, the authors believe that the biological standard (MAC) for an homogeneous working group could be 1100 mg/liter. Such a threshold, which could however be further revised, ought not to be exceeded; higher toluene concentrations will require technical changes of the working environment.