# Human-Related Hazardous Events Assessment for
## 3 Results and Discussion
### Discussion
It is interesting to find that, even though the three most sensitive nodes share the same criticality, the sensitivity level of N_18 is slightly lower than that of \"N_16\" and \"N_17\", which indicates that the identification and prevention of the risks associated with the planned operation on-site are more important than the management for the potential risks associated with the similar operation, although the latter is also important in the safety management system. In addition, the sensitivity of the node coded by \"N_13\" is ranked behind that of the nodes of \"N_16\", \"N_17\" and \"N_18\", even though the hazardous event denoted by \"N_13\" (shipyard failed to superise operators on-site to implement strictly the safety management system) is regarded as being active in the developed CN. It is also noticeable that the absence of risk-prevention measures taken by the operators on-site coded by \"N_25\" is characterized by high in-degree and low sensitivity level, which indicates that the human-related risk management should focus on the causation for \"N_25\", such as \"N16\" and \"N_17\". It can be observed that the unsafe supervision coded by US in Figure 8 is found as the most sensitive node for the personnel suffocation, which implies the well-implemented safety management system is essential for the operation on-site. The similar conclusions were obtained by [PERSON] et al., who argued that \"bad information of subcontractors about safety rules\" played a key role in shipyard injury accidents [13]. Therefore, the supervision for the operators from subcontractors is an effective way to maintain safe operations in a shipyard. The sensitivity level of US is followed by UA, which can be interpreted as the initial causation for the personnel suffocation in the unsafe actions of operators on site. However, the unsafe actions of the operators were not identified as the most active or sensitive events in the present study, which indicates that the consequences caused by the unsafe acts of the operators can be eliminated by the supervision or monitoring arrangements which followed. In addition, according to the contents of Figure 8, the organizational influence (coded by OI) is less sensitive than that of unsafe supervision and unsafe acts based on the accident report, and the difference in terms of sensitivity level between US and OI is as high as 3.17 times; therefore, much more attention should be paid to the factors involved in unsafe supervision rather than factors related to organizational influence. Finally, the least sensitive aspect under the HFACS framework is the preconditions for unsafe acts (UP) which is valued as 0.355, which is followed by the OI with the sensitivity value of 0.487. The sensitivity difference between UP and OI is not considerable for the case in this study, which indicates that the external environment has little influence on the occurrence of the personnel suffocation accident. Overall, the following lessons can be obtained from the case study:  
1. The significance of \"N_13\" (shipyard failed to superise the operator on site) was identified by the proposed methodology in relation to risk propagation based on the perspective of the CN analysis. Therefore, the effective supervision of the shipyard operators on site may be able to intercept risk propagation, despite the occurrence of unsafe acts. 2. The human-related hazardous events coded by \"N_16\", \"N_17\" and \"N_18\" were identified as the most sensitive events for the occurrence of the personnel suffocation accident case study, which indicates that the superintendents or managers of the operators were essential for the safety of the operation. Therefore, an important lesson can be learned: superintendents or managers must pay attention to the behaviors of operators on site. 3.