Abstract
This paper is a follow-up on thirty-eight workers exposed from 1 to 24 years to average benzene concentrations generally between 5 and 50 ppm, but as high as 90 (peak of 140) in the case of one worker. One individual was diagnosed as suffering from mild benzene poisoning and a small number of workers in the group had blood changes considered abnormal, but blood dyscrasia or leukemia has not developed in 13 years after benzene use was terminated in 1964. The population studied was small, but the data, nevertheless, would appear to support the former ACGIH TLV of 25 ppm. One case of mild benzene poisoning reported from benzene exposures of the order of 40 ppm suggests, however, that the margin of safety may be small. The current ACGIHTLV of 10 ppm seems reasonable in the light of our findings.