Ship bunkering, a safety critical operation in marine engineering, can cause drastic environmental damage at sea. Though bunkering presents high safety procedures, minor accidents also can pose potential harm for marine environment and human life. Indeed, it is well-known that numerous bunker accidents can be attributed to different types of human error. Therefore, control of human factor during bunkering operation plays critical role to enhance safety aboard and prevent environmental pollution at sea. This study presents a comprehensive human error prediction during bunkering operation demonstrated with a case study at chemical tanker platform. To achieve this purpose, a Shipboard Operation Human Reliability Analysis (SOHRA) method, which has been developed as a marine-specific approach to quantify human error, is employed. In the view of outcomes, human error reduction measures are recommended. In conclusion, the paper is expected to give practical contribution to the systematically prediction of human error for designated tasks, enhancement of safety control level in operational aspect and protection of the marine environment.