assessment of carcinogenicity and health risks from respiratory exposure to btex compounds at the kermanshah oil depot in iran

In the petroleum industry, oil decomposition releases volatile organic compounds that easily evaporate due to high vapor pressure, posing significant health risks to exposed workers. the aim of this study was to evaluate health risks from benzene, toluene, ethylbenzene, and xylene (btex) exposure among employees at the kermanshah national oil products distribution company. btex sampling was conducted at six loading stations, each with two lines, over 48 hours in 8-hour shifts using niosh method 1501. compounds were extracted with carbon disulfide and analyzed by gas chromatography with a flame ionization detector. the risk assessment followed the singapore method. results showed that benzene and toluene constituted 42% and 33% of btex compounds in the breathing zones of active workers, while xylene and ethylbenzene accounted for 21% and 4%, respectively. the time-weighted average concentrations were: benzene at 0.51 ± 0.14 ppm, toluene at 0.28 ± 0.08 ppm, ethylbenzene at 0.05 ± 0.01 ppm, and xylene at 0.17 ± 0.05 ppm. benzene risk ratings varied from low at station 6 to very high at station 1, line 2, and station 3, line 1. the highest carcinogenic risk from benzene was at station 3, line 1, with an excess lifetime cancer risk of 1.13 × 10-3, while the lowest was at station 6, at 1.10 × 10-5. non-cancer hazard quotients for toluene, ethylbenzene, and xylene remained below 1 across all stations, indicating acceptable risk levels. the study underscores the necessity of continuous monitoring and strong regulations to mitigate btex emission risks in the oil industry. enhancing measurement methods and ensuring compliance with air quality standards will protect environmental health and workforce welfare. future research should prioritize longitudinal studies on the long-term effects of btex exposure.