Posted on 04/20/2013 6:59:56 AM PDT by Sir Napsalot
(snip) What makes ammonium nitrate explosive?
Ammonium nitrate, a common fertiliser additive, is a white crystalline solid at room temperature.
It is stable except when it is contaminated with organic (carbon-based) material.
In practice, it is commonly mixed with fuel oil to form an industrial explosive (called ammonium nitrate/fuel oil, or ANFO) and is widely used in the mining industry.
In the case of the explosion in West, something had to heat the ammonium nitrate in the fertiliser factory to a critical temperature of 300C for it to auto-ignite.
This would need to be either organic contaminants reacting with the ammonium nitrate or a completely separate fire that spread to the ammonium nitrate storage area.
Video evidence confirms a major high temperature fire was burning for some time before the detonation occurred.
At high temperatures, ammonium and nitrogen dioxide are formed when ammonium nitrate breaks down, and can react together to produce massive amounts of heat.
If the heat isn’t dissipated and the reaction rate is allowed to escalate, the reaction will eventually cause detonation.
In West, it would appear all the damage done was caused by the pressure wave generated by the blast rather than toxic gases, though this has not yet been confirmed.
(Excerpt) Read more at theconversation.com ...
Another question. Shouldn’t all firefighters KNOW how to put out this type of fire?
Agreed.
If I don’t get my gun ‘control’, I’ll make you pay.
Who would say that? Who would DO something about that?
Who would need to ‘pay’?
There was a precedent for this huge explosion, which also took place in Texas, when a freighter in the harbor on Galveston Channel. The Texas City disaster of April 16, 1947 is the deadliest industrial accident in U.S. history, and one of the largest non-nuclear explosions. Originating with a mid-morning fire on board the French-registered vessel SS Grandcamp (docked in the Port of Texas City), its cargo of approximately 2,300 tons of ammonium nitrate detonated, killing at least 581 people and setting off a chain of explosions and fires that spread to other ships and the oil storage facility there.
When is 0bama going to go to Texas to ‘stand’ with those people and eulogize the dead?
An earlier fertilizer ship explosion at the Port of Texas City in 1947.
Understandably! That was awful. At least Boston came out looking great as a city. The Mayor should run for Governor. I don’t know his politics but he was incredible during this. Almost as good as Rudy during 9/11!
Hubby is a retired firefighter, 33 years. He said there are certain fires that you just back off and let go. There is nothing you can do about them and will get killed or die trying. Fertilizer is one of them.
An ammonium nitrate fire is difficult to fight.
Fire retardants that focus on excluding oxygen have no effect as the nitrate part of the molecule, which consists of one nitrogen and three oxygen atoms, provides all the necessary oxygen.
The only effective control is to remove the heat, which causes the explosive reaction, by flooding the area with water.
But it’s unknown if the firefighters who responded to the initial fire were even able to commence a water flood before the explosion, which happened minutes after they arrived.
Fire fighting is further complicated by the presence of other hazardous chemicals used to make the fertiliser, principally anhydrous ammonia (liquefied ammonia gas) and nitric acid.
The firefighters on the scene quickly assessed that they could not put out the fire, they then immediately switched to warning and evacuating nearby residents.
And there were safety precautions built in for the plant, of course, now we might hear some violation (OSHA and others could always find something afterwards).
And people lose vigilance and build housing around it for convenience, that's my guess. But we need to know how the fire started in the first place, and why it got out of control so fast.
Fifty years go I was working with a road construction crew. At the gravel pit I noticed empty sacks of ammonium nitrate fertilizer and asked about it.
They told me they would drill the holes deep, place one stick of dynamite in the bottom, then fill the hole with the fertilizer.
That was the first time I learned about the explosive properties of fertilizer.
There is a common joke that firefighters, brave as they are, probably get paid by the gallon due to the massive amount of water they apply to evfery situation. Sometimes they create bigger environmental problems and sometimes they cause things to get catastrophically worse.
There is a community college in Texas City and I worked there as a counselor for the handicapped in about 1986-1989.
The college is not far from Interstate Hwy. 45, the highway from Galveston north. Texas City is not far north of Galveston to give you an idea where it is.
There is a plan to follow when there is an explosion at a plant there. One day at the college, we heard a blast. For the college, the plan was - LEAVE RIGHT THEN. I went to my car and headed north to home.
A blast meant for the people in Texas City to immediately shelter in place and close doors and windows, then wait for further instructions.
My point is, explosions happen there. That complex of chemical plants, offloading dangerous chemicals from ships coming in there, oil coming in by ship, oil refinery plants, etc., is going to create explosions no matter how careful the workers are.
My stepson worked there and was Hazmat trained, so he would head for the explosion rather than flee like the rest of the workers. There are many different companies that have plants there. Every Hazmat worker for any company there would respond to a blast anywhere in that complex no matter which company.
I would never live in Texas City.
Talk about obliviousness from these 'reporters'.
Some one better check if CNN describe West, TX fertilizer plant explosion "as though a bomb had dropped". That would be more apt description.
My son was a fireman in Texas City for 17 years, although he didn’t live there.
He said there are all sorts of cross-agreements between the fire dept. and the fire teams at each plant. When there is a major fire, many different companies will respond.
Texas city explosion in 1947.
http://en.wikipedia.org/wiki/Texas_City_Disaster
2300 tons of ammonium nitrate, diesel fuel, and munitions all in close proximity created one of the largest non nuclear explosions of all time.
On Hannity this morning, he couldn't answer a single correction without blathering and going off on some tangent. Hannity kept re-asking simple questions and ended up interupting him on about half a dozen and answering them himself. It was embarrassing.
This disaster is the dry-chemical version of a BLEVE??
(Boiling Liquid Expansion Vaporization Explosion)
Why don't these fertilizer manufactuers use several smaller underground tanks in bunkers for storage....
...like an ammunition depot??
***********
With the right plumbing and fail-safe (underground) material transport systems...
If a single bunker/tank was compromised by fire-- the remaining storage could be quickly isolated from the others.
Any resulting breach or explosion would be smaller and more manageable than this 2.5 earthquake that killed too many and devastated West, TX.
I pointed this out several times when this first occurred and some were upset. There are legitimate roles for government and this story illustrates that perfectly.
This was a massive failure of proper zoning and regulatory oversight. Period.
I am heartbroken for the firefighters and first responders who rushed to this scene because someone should have known better.
Ammonium Nitrate in any form is not just a great fertilizer, it is an explosive. I think I read that this company generated 2 million dollars in revenue a year. In hindsight, how much cheaper it would have been to move this company far out of town to a safer location with an adequate buffer around the storage? I read the nursing home (133 occupants?) was only 500 feet from ground zero. That is insane. The safety distance for a first responder for a single truck of Ammonium Nitrate is three or more times that distance if it’s on fire on the roadway.
I hope some good comes out of this and other towns and cities will examine what happened with an eye towards preventing a similar disaster in the future. Prayers for this community and those affected.
Fire fighters will sometimes use the spray from their wide area nozzle setting to make a barrier against the heat behind which they can approach the fire.
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