In the era of technological advancement it is still critical to analyze human errors that are responsible for failures of pressure vessels. This is because the adoption of latest technologies cannot totally or abruptly displace the role played by human in design, fabrication and maintenance of equipment including pressure vessels. Thus, this paper adopted a case study research methodology aimed at examining human errors and their causal factors responsible for pressure vessel failure. The analysis feedback established that the slip error in original design contributed to the pressure vessel leak. Furthermore, the design error served as a latent error in the fabrication, inspection and maintenance process until the leak developed in the longitudinal weld of the shell. The lapse error and mistake due to the inadequacy of the repair or replacement procedure resulted in the partial re-fabrication of the shell with its original design error. This discussed the causal factors responsible for the identified human errors and then made recommendations to enhance design and repair or replacement processes so as to minimize human errors. This paper makes contribution by providing insights on pressure vessel failure analysis in viewpoint of human errors and their causal factors.