IDK how many of you have seen the explosion of the fertilizer company in West Texas but it was huge! The reports are that they had 540,000 lbs of
ammonium nitrate on site as well as 110,000 lbs anhydrous ammonia - both of these are explosive under the right circumstances. While ammonium nitrate
will usually not detonate by itself as it needs a booster (initiator charge/blasting cap) of some type, it will catch fire and there is such a thing
as reaching run-away conditions where if there is enough of the fertilizer in one location, it will explode (if on fire or even with minimal ignition
sources). The fire was more than enough to reach the run-away point where it detonated the stockpile. This is similar to black powder which will not
explode (it actually burns very quickly) if put in a pile and lit, but if the pile is large enough, the run-away conditions are met and it will indeed
As for the anhydrous ammonia, this is a flammable gas that is kept under high pressure and sometimes refrigerated. If the temps rise it could cause
rupture of the tank causing a massive explosion which may have been the initiate of the ammonium nitrate stock pile. It really makes no difference
which chemical initiated the explosion as it was basically inevitable once the blaze was out of control, but what we need to look at is the damage
done to the immediate and surrounding area as well as the effects at a distance (from 1km to 40km).
Now take a look at the damage to the OKC fed building which was supposedly caused by 3 - 3.2 tons of explosive (max 7,000 lbs is reported). They have
reported that it was an ammonium nitrate bomb with a fuel added to sensitize it to allow it to be able to detonate. The West explosion had a minimum
of 77 times the amount of nitrate. I'm having a difficult time finding the potential energy of the ammonia but it looks like it could be equal to
anywhere from about 55,000 to 165,000 of ammonium nitrate which would then give a total of 85 times to 101 times the explosive amount of the OKC
Now I'd like you to take a look at the reports of the incident and how far
West plant - Notice that there are still silos standing!!
OKC (they mention a 4m deep crater! The west plant didn't even crator!
(I CAN'T STAND THE PHOTO INSERT OF THIS FORUM - SO UN-INTUITIVE!!!) /rant
Now some people are going to say that the west plant didn't have the material confined like in barrels, well that isn't an issue when you have such
a large quantity that reaches run-away velocity - it doesn't need to be confined (much like the gun powder example).
So what I can say from looking at these two explosions that use very similar explosives (both ammonium nitrate, but one had a little extra ingreditent
to allow it to be sensitized). Now the thing about explosives is that they have a known rate of detonation called the velocity of detonation. The
higher the rate, the more powerful the explosive is, for the most part. These two should have been within 500 meters per second or so but when
looking at the OKC I see something that was most likely a MUCH higher VOD explosive. Ammonium nitrate is about 2,700 to 3,000 m/sec VOD while ANFO is
about 3,900 to 4,200 m/s VOD. I don't think this difference explains the massive difference in the destruction that we see.
There are many explosives that the military uses that have a VOD of 8,400 m/s to 9,400 m/s (as common explosives) and some over 10,000 m/s (more
rare). TNT (the standard by which most explosives are measured) is 6,900m/s and dynamite is 7,700m/s. I think what we are seeing is the effects of
a MUCH higher VOD than what we have been told and I would think that it would be very difficult to get these explosives outside of the military or
some foreign power.
One of the biggest impacts, still being felt, from this explosion is the effect on small farmers. Ammonium nitrate was one of THE BEST fertilizers
you could buy as it was the perfect source of nitrogen, it was incredibly cheap and could be produced out of air! The average price of the
replacement fertilizers is about 6-12x the price of pre OKC ammonium nitrate (when looking at available nitrogen per dollar spend). This has caused
food prices to increase and many farmers to have to sell their farms and many fertilizer companies are getting rich selling their replacement
fertilizers which many believe are no where near as good.
I'm curious of what others think about this, especially those with experience with munitions and have seen the effects of high VOD explosives. To
me, the OKC building looks like the buildings after WWII that were shelled or bombed (and they used TNT as a minimum, so a minimum of 6,900m/s in
those shells, though they often used stronger explosives then).