# Accident Risk Analysis of Gas Tankers in Maritime Transport Using an Integrated Fuzzy Approach
## 5 Discussion  
In this study, a hybrid fuzzy modelling approach integrating Fuzzy Delphi, Fuzzy DEMATEL, and FTA methods was used to identify and prioritise critical risks associated with gas tanker operations. Fault Tree Analysis, as previously highlighted in [65], not only identifies initiating events but also facilitates the assessment of cascading failures  
Figure 7: A risk model for continuously monitoring and evaluating gas tanker accident risks. triggered by human-machine interactions and systemic safety weaknesses. The calculations performed using the FTA method resulted in a value of 0.0938 for the gas fire accident, as shown in Table 8. This value is considered a very low probability, indicating that the likelihood of the accident occurring under current system conditions and with existing preventive measures is statistically very low. Although the probability of an accident is low, it is important to remember that the consequences of an accident would be severe, and even a low probability cannot be ignored. In systems using LNG/LPG, the potential impact of a gas fire could be catastrophic in terms of human safety, environmental damage, and economic loss. A gas leak accident, on the other hand, has a probability of 0.0859, according to Table 8. It has been observed that gas leak accidents have a higher probability compared with gas fire and explosion accidents. The main reason for this is that the number of initiating events that could lead to the release of gas without immediate ignition is higher, as shown in Figure 6. It can be seen that the risks are mainly caused by failures in the factors that trigger or prevent gas leak accidents. The ship's crew and port personnel need to be better prepared for gas leak accidents and to more closely monitor the risks that could lead to such accidents. The environmental impact of the two gas tanker accidents was calculated as 0.02477, according to Table 8. Considering the need to further reduce this value, especially in terms of long-term damage and duration of environmental impact, it is once again evident that all potential risks associated with LPG/LNG tankers in ports need to be monitored more carefully. To enhance the clarity of the discussion, Table 9 summarises the top-ranked risks from the analysis along with their corresponding implications based on model results and expert evaluation. These insights reflect the complex interplay of operational, technical, and systemic vulnerabilities in gas tanker operations and reinforce the multidimensional risk structure outlined in this study. Gases spread rapidly into the environment and, depending on their composition, can accumulate near surfaces due to their higher density than air. This can lead to serious hazards in ship operations due to the flammable or explosive nature of the gases. The physical and chemical properties of liquefied gases, in particular their higher molecular weight than air, resulting in limited dispersion and a tendency to accumulate near surfaces, significantly increasing the risk of explosion in the event of a leak. In addition, the environmental and operational consequences of such leaks, ranging from air pollution to ignition hazards, underscore the importance of rigorous containment, detection, and emergency response protocols. Furthermore, gas dispersion resulting from an accident poses a serious threat to port operations and the surrounding environment. The literature further supports these findings. Ref. [66] presented a case study of an LPG explosion caused by a seal failure under high pressure, highlighting the critical nature of component integrity. Similarly, ref. [67] emphasised that explosion dynamics are strongly influenced by environmental