This study aimed to evaluate the accident-causing factors affecting the total cost of building construction projects using a structural-equation model (SEM). Through the analysis of 35 identified factors categorized into construction, natural disaster, physical and human and psychological domains, this study examined their effects on project costs. The data collected from 120 construction experts in Iraq was analyzed using the SmartPLS software. This study assessed the fit of the measurement model using the following key criteria: reliability, convergent validity and divergent validity. All latent constructs demonstrated Cronbach’s-alpha values of above 0.70 and composite-reliability (CR) values of above 0.70, indicating their reliability. The average variance extracted (AVE) values exceeded the 0.5 threshold, confirming convergent validity. The model also demonstrated acceptable discriminant validity. The results confirmed the significant impact of accident-causing factors on project costs, with "excessive physical activity," "storm," "improper ventilation," "low motivation and low efficiency of the workers," and "fire, explosion and vibration" emerging as the top five influencing factors. These findings emphasized the need for tailored safety measures to mitigate such risks. The study underscored the importance of addressing accident-causing factors to enhance both safety planning and financial outcomes in building construction projects. KEYWORDS: Accident-causing factors, Project cost, Construction-project management, Safety assessment, Structural-equation modeling