In this paper, the most up-to-date research on the buckling of internally-pressurized cone±cylinder intersections and state-of-the-art ®nite element analyses are deployed to provide another anatomy of a pressure vessel failure due to mis-operation overpressure recently reported and analyzed by Jones [Jones, DRH. Buckling failures of pressurized vessels: two case studies. Engineering Failure Analysis 1994;1:155±67]. Existing research on these intersections is ®rst outlined, followed by a description of the buckling strength formulae recently developed to approximate ®nite element buckling loads of the perfect geometry. The validity of these formulae for real vessels with geometric imperfections is next examined through a comparison of theoretical predictions with experimental results, which establishes the limited sensitivity of the buckling load to initial imperfections. The buckling pressure of the cone±cylinder intersection in the failed vessel is then determined using these formulae, while the buckling pressure of the spherical partition in the vessel is evaluated using the ECCS rule. These calculations demonstrate that the cone±cylinder intersection buckled ®rst, followed by the buckling of the spherical partition, which also released the vessel from overpressure. The buckling pressure of the spherical partition is therefore also the maximum pressure exerted on the vessel. This proposition is con®rmed by postbuckling analyses of the vessel.