Urinary metabolites levels in workers exposed to chlorobenzene.

Chlorobenzene is a colorless volatile compound widely used as an organic solvent or a chemical intermediate. There is, however, a potential risk for people engaged in the manufacture and the handling of this compound. The threshold limit value of the time-weighted average (TLV-TWA) for chlorobenzene in air has been set at 75 ppm (350 mg/m3).1) Animals exposed to chlorobenzene excrete this compound into the urine mainly as mercapturic acids or glucuronateor sulfate-conjugates of chlorophenols or chlorocatechols.2-5) Recently, biological monitoring for exposure to organic solvents by means of analysis of their urinary metabolites has become popular. As regards chlorobenzene, biological monitoring by using urinary levels of 4-chlorocatechol, a main metabolite of this halogenated benzene in humans, has been proposed.° In the present paper, we describe chlorobenzene levels in the air and its urinary metabolite levels in workers engaged in the handling of this organic solvent in chemical factories. Healthy male workers (34-49 years old) in two chemical factories were monitored. In these factories, 2-3 t/day of chlorobenzene was used as an organic solvent. In factory A the workers were engaged for 8-11 hours/day in three shifts, and the workers in factory B were engaged for 8 hours/day in a day shift.