An explosion destroyed a propane absorption column during startup following a turnaround. The immediate cause is obvious enough, since plugs were left off of the feed compressor, and the suction valves were left closed, so air was pumped into the system. Detailed modeling of the system provided valuable insights, helped rule out alternative theories for the event ignition, and provided confidence to justify subsequent mitigation measures. An example is provided here of estimating explosion energies by four complimentary methods: modeling fuel/air concentration profiles in the system, column strength analysis, fragment trajectory analysis. and window breakage analysis. The fuel/air concentration profiles showed that the concentrations in the column were largely too rich until the opening of a pressure control valve bled out part of the fuel. The column strength analysis made use of measured shell thickness and known steel properties to obtain an upper bound for explosion pressures at the point of failure. As part of the fragment analysis, we pieced together the column fragments. The characteristic chevron pattern on the edge of the fragments point to the initiating failure point 1/3 of the way from the top. This is consistent with the predicted concentration profile inside the column giving a run-up distance for the explosion. Fragment trajectory analysis indicated explosion pressures and energies. Window breakage analysis made use of a program calculating dynamic window strain. The reasonable convergence of four alternative methods provides increased confidence in the postulated accident scenario.