RESUMO
Gasoline is a complex mixture of more than 500 hydrocarbons. The elimination of lead from petrol has been associated with the addition of significant amounts of hematotoxic monocyclic aromatic hydrocarbons such as benzene, toluene and xylene [BTX]. The main purpose of this study was to ascertain whether exposure to unleaded petrol, under normal working conditions, is associated with any hematotoxic response. This was a historical cohort study in which 200 subjects with current exposure to unleaded petrol from Shiraz petrol stations as well as 200 unexposed employees were investigated. Using standard methods, atmospheric concentrations of BTX were measured. Additionally, blood samples were taken from subjects for routine biochemical tests such as RBC, WBC and platelet count, Hemoglobin, hematocrit and RDW. The geometric means of airborne concentrations of BTX were found to be 0/24, 0/37 and 0/64 ppm, respectively. The results of blood chemistry tests showed that no significant differences exist between both groups as far as biochemical tests, but RDW and hematocrit, were concerned. The average exposure of petrol station workers to BTX did not exceed the current TLVs for these chemicals. Additionally, overt hematotoxicity is unlikely to be the outcome of exposure to unleaded petrol under the conditions described in our study.