I worked 22 years in a demil , RRR , and storage .
In 22 years we had 3 misfires , 3 line incidents, and 2 unplanned detonations .
Most of you likely remember the high profile Marine mortar training accident. Long/short there was a history in the command of abridged training and shortcuts . Protocol for a bloop wasn't followed and a double makes a mess . It makes a bigger mess when the firing point isn't properly sequestered.
The other unplanned detonation was a result of following all of the rules to the letter and a round defect hiding an unusually large quantity of materiel within a casing . The discharge occurred exactly as was intended with all expectations of containment and vent met . Except that it was a quantity of about 105% of design net in 1 of 100 shells and the rest of the load hovered around 70% of design burn off . Zero injuries, zero external property damage , 650k in building and oven repair.
The line event that could have gone very badly was careless handling of large caliber tracers that resulted in a packing fire . There was a rather short discussion about how 300# of tracers burned up and a field trip to the oven where a 25# gob of HE detonated . Complete with the 2" steel deck form fitted to one side of a narrow ga railroad truck . The tour ended in 6 weeks we start running the API and in 4 months we will run HE . The packages will be basically the same . In that moment it clicked for most of the crew that the fire was an inconvenience and that the procedures and handling rules were there for a very very good reason .
The blow out walls are and have been since before 1860 been glass or very thin panel fiberglass with extremely low shear properties. Think 1/4 sheetrock fragile. The designs are such that there is little to no pressure build and the blast is directional to another deflection or open space dissipation plain . The 1938 ,1950s ,1980s and 1998 ACE designed ordinance handling buildings are basically unchanged from the red brick and glass BP plants of the Civil War .