Detailed re-analysis of the catastrophic failures of four 2-tonne LPG vessels subjected to jet fire attack indicates that the severity of the event and the intensity of the fireballs formed may be a function of the initiating mode of vessel failure and the thermo-hydraulic state of the contents. The mechanism of vessel failure appears to be a two-step process; the formation of an initiating overpressure crack in the high temperature vapor wetted walls of the vessel, followed by a final catastrophic ‘unzipping’ of the containment and the nearly instantaneous release of its contents. The distribution and flashing of the lading causes a fireball. The surface emissive power of the BLEVE fireball does not appear to be directly related to the ‘superheat’ of the contents at failure. Possible reasons for the final rapid failure of the vessel are either crack instability or the rapid quenching of the crack tip, due to its two phase discharge, that results in large local thermal stresses.