The present study provides a robust and systematic approach for the analysis of accidents in enclosed spaces onboard ships. An enclosed space is considered a hazardous working environment since its atmosphere contains substances harmful to health. Despite improvements in safety standards, accidents in enclosed spaces remain a major concern for the shipping industry today. Therefore, this paper analyses accidents to identify the factors causing them. The study makes use of a fuzzy DEMATEL (Decision Making Trial and Evaluation Laboratory) method to evaluate causal factors which can be mitigated through the adoption of certain measures. The study focuses on 101 enclosed space accidents/incidents, which have led to 93 deaths and 96 injuries, and determines their causal factors. The study findings emphasize the fact that human error and weaknesses in organizational factors are primarily responsible for accidents in enclosed spaces. Accordingly, effective control measures have been identified which can prevent accidents and enhance the safety and sustainability of the shipping industry. This study overall makes a contribution to safety management in the shipping industry.