Occupational safety dynamics in onshore LNG receiving terminals: A systems modeling approach

In onshore LNG receiving terminals (LNGRTs), any unsafe condition and/or act that may cause fire and explosion during LNG processes may lead to major occupational accidents that may endanger people, equipment and the environment. Hence, to prevent accidents, determining factors that result in unsafe condition and/or act is crucial. LNGRTs are complex systems of interacting elements of managerial and employee decisions pertaining to occupational safety. Accordingly, in this study, based on system dynamics approach, a dynamic simulation model is developed to unravel the dynamic feedback structures that operate over time and can reveal unsafe conditions and/or acts, which signal probabilities of major occupational accidents. To gain insight into the system, besides literature review, fieldwork is done in a major onshore LNGRT. The model structure comprises the activities of LNG processing, equipment maintenance and repairing, employee training, where the management's time allocation decision under specific resource constraints is the fundamental driver. The model simulates for 5 years and is validated first structurally then behaviorally. Subsequently, system behaviors are analyzed by applying several scenarios and policies on the model. Though these analyses, the model behaviors reveal that possibility of major occupational accidents increases by decrease in allocated labor time for maintenance that increases unsafe conditions and by decrease in allocated labor time for training that increases unsafe acts. The model can also be used as an experimental platform to test the influence of several factors on safety, such as; schedule pressure, incident learning, equipment reliability, turnover rate, overwork, and occupational experience of employee.