Biological threshold limits for benzene based on pharmacokinetics of inhaled benzene in man.

Volunteers were exposed to benzene, 2--10 ppm, under controlled conditions up to 6 h a day during five consecutive days. The accumulation and elimination of benzene was measured by determination of benzene concentration -- down to 0.001 ppm -- in exhaled breath. From these observations, a multicompartment model, which approximately describes the kinetics of benzene elimination and accumulation has been designed. On the basis of this model, benzene concentrations in breath, corresponding to exposure levels of benzene, have been estimated. Thus, at a daily exposure to 10 ppm the exhaled benzene concentration in the morning after a day of exposure will not exceed 0.1 ppm.