Systemic human factors analysis of hydrogen fuel supply in maritime operations: integration concept of STPA, SLIM, and BN

The adoption of alternative fuels such as hydrogen introduces complex safety challenges in maritime operations, making the integration of human factors essential. Human performance, seafarer capability to operate novel equipment, and interactions with emerging automation significantly influence operational safety. In addition, the unique properties of hydrogen present occupational hazards that heighten risks during shipboard operations. Therefore, human factors must be a central element in analyzing the safety of hydrogen-powered ships. Furthermore, most of the studies still utilise the linear accident causation method, which will neglect the complex socio-technical relationship between the human as the operator, control logic, and the components. Therefore, the adaptation of the novel technologies of hydrogen in the ship should be analyzed in a systemic approach. This study conducts a safety analysis of hydrogen-fuel supply in maritime operations by applying the System-Theoretic Process Analysis (STPA) to identify potential unsafe human actions and their interactions with other system components. These unsafe actions and loss scenarios are then linked to relevant human Performance Shaping Factors (PSFs), enabling a structured understanding of the human contribution to system risks. To provide a quantitative assessment, Bayesian Networks (BN) and the Success Likelihood Index Method (SLIM) are integrated to estimate the probability of human control action within the systems. The findings of this study will support the evaluation of human performance in operating emerging hydrogen technologies on ships and inform the development of regulatory measures and training programs. Ultimately, the results aim to bridge safety gaps and strengthen the safe implementation of decarbonisation strategies in the maritime sector.