Water caused shell to explode in 1972?

[displayfireworks1]

What was a display shell made of in 1972 that water caused it to explode? Please read the documents below that describe the event in 1972.
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https://www.youtube.com/watch?v=_fDV7SDybzM
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http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=2838&stc=1
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http://www.pyrotalk.com/bulletin/attachment.php?attachmentid=2839&stc=1
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http://pics2.city-data.com/city/maps/fr3749.png

[Kenny East]

I couldn't say for 100% magnesium with ammonium perchlorate, used for a rising effect... Lift charge got wet, as did the rising effect. The rapid oxidation of the magnesium and ammonium perchlorate are catalyzed by the water causing ignition.. Leading to a flowerpot. Just speculation, that was well before my time. I do know they used some very questionable chemicals and formulas back then. Picrates, tetra oxides, and a lot of it was based with what ever oxidizer the factory had on hand.
Though water reacting with organic sediments can produce weak acid, which could have caused the mentioned reaction/explosion.
Also zinc/sulfur reacts strongly to water and burns similar to flash powder.

[displayfireworks1]

It looks like it was a six break 4 inch shell in a steel mortar. I don't know in this situation , an old timer told me stories of inexperienced people loading some Dago Bomb into mortars because they looked like shells but are ground salutes. I never say one so I do not know. I just find it hard to believe that water seeping into a mortar is going to cause not one but two shells to explode by a catalytic reaction. The more I think about it, I suspect water in the mortar destroyed the lift , those old multi-break shells were top light by the quick match , thus if the bottom lift was wet, the shell would not leave the mortar , however the break charge would still ignite from the top. This would cause the shell to break in the mortar. Anyone else have a theory on this one?

[PyroJoeNEPA]

I think you summed it up very well Dave--water neutralized the lift charge but the shell was lit from the top in the gun and would and the pipe could not contain a multi break going off in the pipe. Even worse with a bottom shot--which pretty much every multi break shell had back in the 70's. Tragic story!

[displayfireworks1]

So much for the so called listed "Several pyrotechnic experts" and the water catalyst theory in 1973. Funny thing is there was most likely many more pyrotechnic experts back in 1973 than there are now. Almost all of the companies were building shells and apparently their expertise may have not been all that.
I am finding this document from back in the day very interesting. If I find something else similar I may post it.

[jamisonlm3]

The time fuse was lit from the top? I can see how that could be a recipie for disaster. At least with it in the bottom with the lift charge, there's the chance that it might not ignite with waterlogged lift. How did water get into the mortar? If they were steel mortars, I assume they had a welded steel plug? Was there heavy rust or poor welds around the plug? The water table here is around 3ft down. Once you dig that far, you hit water. If there were holes around the plug due to poor welding or heavy rust, water wouild have collected in the bottom of the mortar like a well. It seems that putting the shell into a simple trash bag might have prevented this. I've wondered why the shells we get come in little platic bags. Maye this is one reason? Checking the mortars beforehand also. That's my thoughts. To me, this was avoidable. Thanks for posting this Dave.

[displayfireworks1]

It is a common misconception the bag on some display shells is to keep the shell dry in the event the mortar has water. That is not true. The bag is keep powder leakage contained if it would occur from one of a multitude of reasons during transportation. It is not necessary to remove the bag when loading a shell. You sometimes see groups of shells bagged and sometimes individual shells bagged. This was told to me years back by a very reliable source.

[Kenny East]

Yeah, i missed the part about the type of shell used... Water destroying the lift charge is most likely to blame.

[Rick_In_Tampa]

"The Commission couldn't tell from the official reports it examined, the coroners inquest, or persons it interviewed, the exact portions of Bulger's body that absorbed fatal damages."

Seems to me this Commission wasn't very adept at getting anything right. I find it hard to believe the coroner was really that clueless he/she couldn't determine which part(s) of this guy "absorbed fatal damages." That should have been the easiest part of this investigation.

[Mattp]

Also to say the shrapnel fell as far as 2 1/2 city blocks.. we all know a city block means kind of far.. but on an official document like that.. how the hell is that the measurement they use.. pretty crazy