A cytogenetic study on workers exposed to low concentrations of benzene

A cytogenetic study was performed on 22 healthy workers engagedin benzene production and exposed to low concentrations of benzene,ranging from 0.2 to 12.4 p.p.m. (threshold limit value 10 p.p.m.).Workers were divided into two groups according to the differentlevels of exposure, inferrable also from the concentration ofbenzene in the alveolar air and the levels of urinary phenols.Each exposed subject was paired with a suitable control, livingin the same area and of similar smoking habits and age. No statisticallysignificant increase of sister chromatid exchange (SCE) frequencywas observed in the exposed groups. In controls, SCE frequencywas positively correlated with age and smoking habits. Amongstructural chromosomal aberrations, only the chromosome-typeones were significantly higher in exposed than in control subjects,and their increase was still significant when gaps were discarded.