BTEX exposure assessment and quantitative risk assessment among petroleum product distributors

The aim of this study was to evaluate benzene, toluene, ethylbenzene, and xylene (BTEX) exposure among workers at four stations of a major oil distribution company. Personal BTEX exposure samples were collected over working shift (8 h) for 50 workers at four stations of a major oil distribution company in Iran. Measured mean values for workers across four sites were benzene (2437, 992, 584, and 2788 mu g/m(3) respectively), toluene (4415, 2830, 1289, and 9407 mu g/m(3)), ethylbenzene (781, 522, 187, and 533 mu g/m(3)), and xylene (1134, 678, 322, and 525 mu g/m(3)). The maximum mean concentration measured across sites for benzene was 2788 mu g/m(3) (Station 4), toluene was 9407 mu g/m(3) (Station 4), ethylbenzene was 781 mu g/m(3) (Station 1) and xylene was 1134 mu g/m(3) (Station 1). The 8 h averaged personal exposure benzene concentration exceeded the recommended value of 1600 mu g/m(3) established by the Iranian Committee for Review and Collection of Occupational Exposure Limit and American Conference of Governmental Industrial Hygienists. Mean values for excess lifetime cancer risk for exposure to benzene were then calculated across workers at each site. Estimates of excess risk ranged from 1.74 +/- 4.05 (Station 4) to 8.31 +/- 25.81 (Station 3). Risk was assessed by calculation of hazard quotients and hazard indexes, which indicated that xylene and particularly benzene were the strongest contributors. Tanker loading was the highest risk occupation at these facilties. Risk management approaches to reducing exposures to BTEX compounds, especially benzene, will be important to the health of workers in Iran.