[Prognosis and determination of the threshold of chronic effect of carbon disulfide and styrene].

Two series of studies were carried out: I--in workers exposed to four different mean annual CS2 concentrations--6 mg/m3; 12 mg/m3; 51 mg/m3 and 247 mg/m3 and II series-in workers exposed to three styrene concentrations--I mg/m3; 40 mg/m3 and 400 mg/m3. The results obtained in series I show the role of the primary toxic effect (inhibition of oxidases with mixed function) and of the adaptation reactions to it with a view to accurate specifying the threshold of chronic CS2 effect. The mathematical expression of the correlation between styrene concentration in air and blood, of phenyl-glyoxylic and mandelic acid in the urine of the exposed subjects enables the prognosis that the threshold of the noxious styrene effect is within the range of 150 mg/m3 to 250 mg/m3. A reduction on CS2 MAC is proposed--from 10 mg/m3 to I mg/m3 and the correction of styrene MAC--from 5 mg/m3 to 30-50 mg/m3.