The melt - pour building. The kettles are where the TNT is melted. About 180 deg. F. is the base temp but not efficient. The kettles will usually be double wall and heated by pressurized steam at about 245 deg. The RDX is added during TNT mix process. The two explosives do not chemically combine. The mixing is to get the RDX particles uniformly distributed in the pour. Non-uniform mixing is behind the premature detonation of artillery projectiles with this mix of TNT+RDX= Comp B. Those projectiles have been withdrawn from service, melted out, and refilled with either a straight TNT or an insensitive filler. The use in blasting charges as here does not pose a risk like a fired artillery round. Something happened in the mixing. An hydraulic motor will spin an arm with paddles attached. Everything is non-sparking. Iowa Army Ammo Plant had canoe paddles strapped to the mixing arm. So what happened? Some part of the mixer broke? Someone’s false teeth fell in and pinched causing a spark …? Don’t laugh, it’s happened at Radford Ammo Plant and one other I can’t recall right now. Neither TNT or RDX are very sensitive (we’re talking relatively here). Unfoutunately, any key evidence is oblitered in the explosion.
A few observations from the article:
Given the active constituents listed in the story, I would guess that this is some form of HBX (“High Brisance Explosive” or “High Blast Explosive”) or something similar, which is an ordnance-grade explosive of WWII provenance. I’m kind of surprised to see it still being used but it was known to have a propensity for spontaneous explosion if humidity wasn’t tightly controlled. The article claims that they are making a ‘cast booster’ which for military use suggests a hyperbaric explosive or something used as the booster charge in a bulk insensitive explosive for demolitions applications.
Melt (pour) casting operations are always risky, and to my knowledge most manufacturers now do these as remote operations that are done in bunkerized cells or entirely separate facilities. There should be no possibility of the detonation of one ‘kettle’ causing sympathetic detonation of other kettles. That there could be a detonation of 24,000 pounds (the article doesn’t specify whether that is actual weight or TNT equivalent, but regardless it is a lot) indicates a gross and systematic lack of safety planning and energetic material management. This kind of detonation could occur where there is an unavoidable collection of energetic material, such as casting heavy bombs or solid propellant rocket motors (again, always done as a remote opeartion today) but this doesn’t seem to be a large ordnance factory.
There should not have been 16 people inside of a building where any kind of casting operations or other direct handling of unconfined energetics was occurring, even if it had to be a crewed operation of some kind. This is such an unconscionable lapse of occupational safety and personnel protection that I don’t even know how anyone could have considered this acceptable. This is literally a criminal degree of negligence which should result in responsible parties seeing criminal prosecution. There also shouldn’t have been anyone outside but in proximity to the lab; the exterior should have been cleared to the Q-D (quanity-distance) range and warning lights and barriers placed across all roads to the facility.
Given the previous lapses in safety and contamination, this entire facility should be shut down until a rigorous audit of their safety practices and procedures, facility siting and protection, and management practices for training, scheduling of operations, et cetera are thoroughly assessed. This is an accident that should not have happened, and even if unforeseen events caused an explosion shouldn’t have resulted in this large of a blast and mortality. This is doubtless the result of many different lapses of judgement and safety requirements driven, I suspect, by cost cutting or highly optimistic delivery schedules.
Stranger
Excellent comments.
I wonder what a detailed IG inspection of all the other DoD energetics suppliers large and small might turn up?
If only we still had a functioning trustworthy DoD and IG thereof to perform these inspections.