## 1 Introduction
Therefore, recycling hazardous wastes generated during the construction process and promoting the implementation of lean logistics management can reduce pollution and occupational safety hazards, create a favorable production environment, improve the efficiency of cruise ship construction, and ultimately achieve green safety benefits. Although several studies have explored the application of reverse logistics in hazardous waste management and have been applied to some extent in practical engineering management, studies for the specific field of cruise ship construction are still rare, especially considering the safety of personnel and environmental sustainability in high-risk environments. Most of the existing studies focus on areas such as e-waste [13; 14; 15; 16], medical waste [17; 18; 19], waste oil [20; 21; 22], and are primarily focused on economic analyses [23; 24; 25; 26; 27], ignoring the integrated issues of safety risk management, environmental sustainability and waste treatment, which limits their practical application in complex shipyard environments. Therefore, despite its great practical significance, there are few studies on the reverse logistics management of hazardous waste generated during cruise ship construction. In order to fill the gap in the academic literature, and address the safe and effective disposal of hazardous waste during cruise ship construction, this paper proposes a hazardous waste reverse logistics network optimization model specifically for the cruise ship construction process, which takes into account the cost, efficiency and safety risks, and aims to ensure efficient and environmentally friendly cruise ship construction. This study analyzes the cost structure associated with different transport routes and modes to identify the most economically efficient transportation solutions, ultimately reducing overall operating costs. By optimizing transport scheduling and vehicle allocation, the efficiency of material recovery and transport was improved to ensure that hazardous waste can be transferred to designated treatment facilities quickly and safely. Fuzzy logic was used to assess operator safety satisfaction to ensure that potential safety risks can be effectively identified and mitigated during the transport process. To achieve the above objectives, we designed a discrete crow search algorithm, which has strong global search capability and adaptability, and is able to find the optimal solution in a complex logistics network. Through simulations of operational scenarios, we optimized hazardous waste transport scheduling  
Figure 1: Shipbuilding process for integrated hull construction, outfitting, and painting. Figure 2: HSE cross-relationship diagram. to maintain the safety and health of operators, while achieving economic benefits. This comprehensive approach not only advances the management of hazardous waste in cruise ship construction, but also contributes to sustainable practices in manufacturing. The key contributions of this study include the following:  
1. Integrated Model Innovation: A reverse logistics network optimization model that integrates safety, cost and efficiency is proposed, focusing on hazardous waste management during cruise ship construction and quantifying the safety service level of different solutions. 2. Vehicle Allocation and Safety Management: Various vehicle types are introduced to test the impact of different forklift combinations on cost and safety service levels, while safety risk management for field operators is enhanced through time window settings. 3. Optimized Dispatch and Efficiency Improvement: Developing a centralized vehicle dispatch methodology to significantly improve the efficiency of managing the recycling and transportation of hazardous waste materials, ensuring fast and safe transfer to designated treatment facilities. 4.