A risk assessment of inhibited cargo operations in maritime transportation: a case of handling styrene monomer

Hazardous cargo handling on tanker ships involves various risks that could lead to accidents such as explosion and fire. Investigating these risks is crucial to safeguard life, property and the marine environment. This paper performs a risk assessment specific to hazardous cargoes with special requirements. It addresses the risks of inhibited cargo operation, which has not been adequately studied in the literature despite its criticality. Styrene monomer is selected as the inhibited cargo type since failures during its handling may lead to polymerisation and catastrophic consequences. Using the Failure Modes, Effects and Criticality Analysis (FMECA) 24 failures are identified, and their occurrence, severity and detection aspects are evaluated by experts familiar with the process. In addition, a rule-based fuzzy logic technique with Gaussian membership functions is employed to support the traditional FMECA application. The integration of methods helps to deal with the limitations of FMECA in the calculation of risk priority number (RPN). Based on the fuzzy RPN results, failure modes are prioritized and preventive actions are presented for the high-ranked failure modes. The outputs of the study could help to increase the awareness of operators and interested individuals concerning the risks of tanker cargo operations with special requirements.