Short time exposure to benzene and gasoline at garages

This study was carried out to evaluate car mechanics' short time exposure to benzene and gasoline vapours. The measurements were performed during adjustment of direct fuel injection systems, carburettor adjustment and fuel system repairings. The vapour concentrations from unleaded and leaded gasoline were compared during different workphases. Biological monitoring were used to evaluate total exposure to benzene. The mean short time exposure level of car mechanics exposed to unleaded gasoline vapours was 8±6 cm 3/m 3 and 26±19 cm 3/m 3 to leaded gasoline. The concentrations of benzene in breathing zone varied from the detection limit (0.2 cm 3/m 3) to 1.3 cm 3/m 3 from unleaded gasoline and from the detection limit to 3.7 cm 3/m 3 from leaded gasoline. The average background concentration of gasoline vapours in the garages were 6±7 (SD.) cm 3/m 3 and concentration of benzene was under the detection limit. The samples of benzene in blood were collected 2–9 hours after the exposure and concentrations ranged from 3 to 16 nmol/l. When approximated to the time point of 16 hours after exposure according to the elimination rate constant the benzene levels in blood ranged from 1.6 - 11.1 nmol/l. Biological monitoring of benzene showed exposure levels higher than expected according to the corresponding air measurements (TWA 8h). Comparison of expected benzene levels in blood if no dermal exposure were present to the calculated levels 16 hours after the exposure showed that dermal exposure in the motor repairing work may be the most significant route (80%) of exposure. Leaded gasoline caused higher exposure than unleaded gasoline.