Occupational exposure of petroleum depot workers to BTEX compounds. BACKGROUND: Benzene, toluene, ethylbenzene and xylene (BTEX) are the most important toxic volatile compounds in the air and could be easily absorbed through the respiratory tract. In recent years, the risk of exposure to BTEX compounds, especially benzene as a carcinogen, has been considered in petroleum depot stations. OBJECTIVE: To assess the occupational exposure of petroleum depot workers in Iran to BTEX compounds. METHODS: After completing a questionnaire and assessing o