There is no doubt that chemical materials are the toughest cargoes carried by ships, as they require special expertise in terms of handling, storage and transportation aspects. As such kind of cargoes may be explosive, toxic, corrosive and contaminant to environment and dangerous for human health. There is always a need for careful and professional operations. The chemical transportation industry passionate to deal with root causes of cargo contamination and produced strict solution/procedures to reduce the chemical cargo contamination events. However, to our knowledge there is not any study in the literature investigates root cause of cargo contamination. Procedures implemented are practical experienced based. The main purpose of this study is to identify an appropriate management tool to mitigate the cargo contamination risk by reducing the occurrence probabilities of the root causes, which can be achieved by Fault Tree Analysis (FTA). FTA is a systematic way to obtain reliability of complex systems both qualitatively and quantitatively by using exact values of root causes' occurrence probability. However, probabilistic values are inadequate to use FTA method. Therefore, we employed Fuzzy Fault Tree Analysis (FFTA) approach to analyse root causes of contamination and obtain the occurrence probabilities. (C) 2015 Elsevier Ltd. All rights reserved.