It is crucial to disclose the causal factors to eliminate the oil spills arising from bunkering operations. To address this phenomenon, this paper presents a novel model for causal mechanism of oil pollution. For this purpose, this research examines the probabilistic relationships among the causal factors which are revealed qualitatively and quantitatively utilizing a Fuzzy-Bayes Network approach. Sensitivity and validation analyses are executed to improve the accuracy of outcomes. Findings of the research indicate that existence of overflow, the existence of operational causes, and crew causes appear as the major contributory factors to account for the occurrence of pollution. Furthermore, it was found that damaged connection hose, existence of over-reliance, and bad flange connection have the least impact to explain the occurrence of oil pollution. P&I Clubs, regulatory authorities, and shipowners can exploit the results of this research to mitigate oil pollution risk stemming from bunkering operation.