In this work, case study investigated the premature failure of the SS316l stainless steel bellows expansion joint at the outlet of the pipeline crude oil storage tank in the Nasiriyah oil field, Iraq. The multidisciplinary team identified potential causal factors that could contribute to the failure, including thermal expansion, pressure build-up, design aspects, and operational parameters, and sub-factors were determined and classified as primary, secondary, and non-contributors. The results indicate that the expansion joint had over-expanded from its original length of 2100 mm to 2570 mm as per site inspection report, which was identified as excessive thermal expansion of the pipeline and trapped crude oil, expansion joint stress, and internal pressure buildup with secondary contributing factors including high ambient temperatures, direct sunlight exposure, and the absence of a pressure relief mechanism in the pipe as a closed system. These factors result in excessive deformation, exceeding the yield strength of the material, and compromising the integrity of the expansion joint. This study will serve as a foundation for developing a comprehensive risk management plan, incorporating detailed assessments of the system and improved design specifications to ensure the integrity and reliability of the crude oil storage system while minimizing future risks related to pressure buildup and thermal expansion.