While the final nail may likely have been adiabatic combustion / contamination - it is interesting that the failure was at the valve stem and that it looks like it has failed from fatigue ("shiny" outer "rings/" with a rough inner section). Most other adiabatic combustion / contamination failure points seem to be through the diaphragm/bonnet or the gauges (thinner parts where there is also a larger surface area for the increase in pressure to act on).Another oxygen regulator explosion/fire recently. This time at Waikato University. A worker at the University was hospatilised with burns and hearing loss after an old regulator exploded when opening for use. Having old regulators myself I was unaware the risk that these pose. The people know of this the better — Grant Franklin
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