Oil/chemical tanker ships are designed to transport liquefied chemicals in a series of discrete cargo tanks. Even a minor crack in the cargo tanks can have catastrophic consequences financially, and for the marine environment and human life. For oil/chemical tanker shipping operations, risk analysis is of great importance to improve safety and minimise risk at the operational level during the transportation of chemical cargo. This paper focuses on the risk of cargo tank cracking on oil/chemical tanker ships. The robust bow-tie risk analysis method is adopted under the Dempster–Shafer (D-S) evidence theory – Human Error Assessment and Reduction Technique (HEART) approach. In Bow-tie, which analyses the possible causes and consequences of failures, the top event is determined as the risk of cargo tank cracking on an oil/chemical tanker. The probabilities of basic events are calculated with D-S evidence-based HEART, where expert opinions are combined. Besides the theoretical contribution, the outputs of the paper provide practical contributions to oil/chemical tanker owners and operators, safety researchers, safety inspectors, and superintendents by providing the information needed to minimise the risk associated with cargo tank cracks in oil/chemical tankers.