Background & objectives: Uncertainty and variability are inevitably included in health risk assessment. The objective of this study is to develop an integrated approach to evaluate risks of benzene using fuzzy logic to consider variety of factors and actual respiration rate of cases.

Methods: This is a descriptive analytic study. In this study an integration model was created based on fuzzy logic and it was invented by using fuzzy toolbox in Matlab software, then by using IRIS instruction, the CDI rate and cancer and non-cancer risk was calculated. A questionnaire was also prepared to expand on the Information about jobs, activities, tasks and sites came from interviews with employees. �Active sampling was performed within a week for each season and finally 280 samples were collected after one year.

Results: The results of air sampling have shown the concentration of benzene in the air at the site and loading units is beyond the standard (PEL-TWA). results of risk assessment indicates that among� different groups , due to more contacts with pollutants, cancer risk in people working in loading Units is higher than the Standard measure , and requires controlling action.

Conclusion: The proposed approach handles the uncertainties in health risk assessment using combination of probability and fuzzy set theory. The results show that the assessment of risk with this method will cover wide range of affective factors and risk assessment will be dealt with more details and explanations.