Big as a Nuke
I am trying to work this idea into a short story and decided to throw it out here
Terrorists in the United States built a very effective bomb out of fertilizer and diesel fuel. Large ships, called bulk carriers, carry, among other things, fertilizer. There are about 7000 of them in service worldwide. They are powered by diesel engines. For a bulk carrier to take on a load of fertilizer and then a large amount of diesel fuel would not raise eyebrows anywhere. If they went to another port for more fuel, who would notice?
Bulk carriers carry from 10,000 to 100,000 DWT [dead weight tons] of fertilizer. This is a LOT more than a Ryder Rental truck carries. We all saw what that Oklahoma City bomb did. An entire ship could be turned into one humungous bomb. These ships arrive at U.S. ports every day.
Would current procedures stop this kind of attack?.
Are you familiar with the ship explosions at Texas City in 1947 and Halifax in 1917? Texas City was mostly ammonium nitrate and sulfur, although there were hydrocarbons mixed with the ammonium nitrate. Halifax was a complex mixture. Halifax also included volatiles that probably led to a fuel-air explosion of greater than the apparent explosive load. Estimates are that Texas City was equivalent to 2-4 KT and Halifax about 9 KT of TNT. While there have been even larger high explosive detonations in weapons research, the next larger blast to Halifax was Nagasaki.
There were some lesser ones elsewhere, and also industrial explosions on land. One exceptionally nasty one happened in 1943 in the harbor of Bari, Italy. A German airstrike hit a number of ships, including what was thought to be "just" an ammunition ship, the John Harvey. The ship exploded. What had been highly classified and not known to the rescue and medical personnel was the ship also had been carrying a strategic reserve of mustard gas, to be used if the Germans first used chemical warfare.
A bulk carrier taking on a load of ammonium nitrate gets extremely close scrutiny, as a result of those two disasters. Liquefied petroleum gas carriers also are watched and inspected very, very carefully.
In those quantities, I don't think you could mix fuel oil or another liquid with it very efficiently. McVeigh had to mix things manually -- IIRC, he used the more effective nitromethane. Part of the problem of Texas City is they tried steam smothering, which was, chemically, about the worst thing you could put on hot ammonium nitrate.
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Howard
*equal opportunity offense to both extremes*
October 7, 2006 5:47 PM | Reply | Permalink
A few thoughts, although somewhat light on specific facts, as i don't wish to be a spreader of nastiness.
October 7, 2006 6:05 PM | Reply | Permalink
I do know of the Texas City explosion and in my story, at least so far, Houston, via the ship channel, is the primary target and Texas City the secondary. I lived in Houston ‘till the age of nine and recall miles of refineries and chemical plants along that part of the Gulf Coast.
A bulk carrier taking on a load of ammonium nitrate gets extremely close scrutiny, as a result of those two disasters.
I’m open to information here. How do you know this? Can you give me any links? What do they scrutinize, do they satisfy themselves that it is indeed ammonium nitrate that is being loaded? What good does that do if they find that what was intended to go into the ship is exactly what is going into the ship?
I have thought about the mixing problem. McVeigh used, I believe, bagged fertilizer poured into 55 gallon drums to which he then added diesel and , as you say, probably some accelerants like nitro methane. In my scenario [which will work within the stories own reality because that is how I am writing it, but I hope to get it right. I really don‘t like stories/movies which have important parts of the plot which just wouldn‘t work in real life.] we are dealing with a liquid tight container, the ship. Bulk carriers are a relatively new type of vessel. They have no internal bulkheads. The fuel tanks run along the sides and give structural integrity and create a tapered interior shape which facilitates loading and unloading of bulk goods like coal, iron ore, and ammonium nitrate. They are not intended for packaged goods or containerized freight.
To make the bomb I would load the ship with ammonium nitrate, say three quarters full, and put rubber bladder tanks on top of the A.N. and fill them with diesel. I would put command detonated explosives in each end of the A.N. wired together to go off simultaneously. This would direct the initial explosion into the bulk of the explosive charge. When the right number of days away from the target, I would pump most of the ships fuel onto the A.N. Later I would puncture the bladder tanks and let them drain through the A.N. I have handled large trailer/spreaders filled with fertilizer and it appears that it is something through which the diesel would flow and saturate.
In a story this will definitely work, but I expect that it would in real life as well. The explosive effect might not be maximized, but maybe McVeigh’s wasn’t either. Remember that a bulk carrier might become a bomb 25000 times as big, by weight, as the one that went off in Oklahoma City.
I would be happy if you were to convince me either that the bomb I have described would not explode or that the logistics are such that it could not be carried off.
October 7, 2006 7:51 PM | Reply | Permalink
As one starting place for tracking, CHEMTREC. Another, describing Coast Guard procedures for Honolulu Remember that it would be unlikely anyone would ship NH4NO3 to the US; the Texas City explosion was of a load to be exported. Unfortunately, the local fire department did some things reasonable for other kinds of hazardous substance that were about the worst possible thing to do: steam under pressure. In 1947, there were no HAZMAT data bases immediately available.
One of the most frightening things are LNG carriers, which look like nothing but an LNG tanker. They are met well out at sea, and inspected there. Yes, there are a lot of hiding places on a ship.
ANFO (commercial ammonium nitrate/fuel oil) is widely used in quarrying and mining, with enough oil so it can be pumped -- this is less than the optimal explosive mix. It's a relatively insensitive explosive. There's a standard 40-pound military cratering charge of ammonium nitrate, basically intended to move earth. A blasting cap won't set it off; you have to put the blasting cap in a booster of tetryl or TNT.
One of my questions, for a large mass of either NH4NO3 or ANFO, is, if you start the detonation in one place, will the detonation wave slow down as it propagates, so it won't be sufficiently fast to trigger further detonation. Texas City was a special case of confinement, heating, and breakdown. I suspect there is a maximum propagation distance before you need more booster charges, when you are dealing with a shipload. I don't think Primacord has the energy to do it, but you'd need either a complex electrical firing system or a Primacord grid with booster blocks at the crossing. As you may know, pipe bombs are more dangerous because the pressure rises and the reaction is more intense due to confinement. Even in nuclear weapons, there is compression and containment to get high yield, before the explosion scatters itself below critical mass.
McVeigh had a relatively small amount, and was also using higher-energy nitromethane. There are some other chemicals that would boost the reaction.
I am extremely concerned with some potential terrorist activities involving the chemical industry, but a shipload of ANFO is fairly far down on my list of things to worry about.
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Howard
*equal opportunity offense to both extremes*
October 7, 2006 8:37 PM | Reply | Permalink
The links didn’t work so I still don’t know anything about how loads of amonium nitrate are scrutinized and to what point.
I am extremely concerned with some potential terrorist activities involving the chemical industry, but a shipload of ANFO is fairly far down on my list of things to worry about.
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Same for me, I live within sight of th Rocky Mts. so I don’t worry about getting blown up in a port explosion. Seriously though, this is interesting but would be more so if you would respond more directly to the questions that are raised. You did not say, so I ask you again, would the bomb I describe, or one very similar with a few tweaks, blow up. I think it would. Maybe it would need a more powerful initial detontion, or maybe the initial detonation points would have to be spaced differently than I have postulated, to make it as effective as possible. The point is, would it explosde? Would it be powerfull?
Lets go through some arithmetic. I have to make some assumptions. Say that McVeigh’s bomb totaled 8000 lb.s. of material. Four tons. I bet it was less. Say it was optimally effective, though I bet it wasn’t. Now let’s say that the bulk carrier has a gross cargo weight of 100,000 tons. That is, 200.000 000lbs. Let’s also say that this makes a bomb which is only 50% effective. Let’s now call it a 100 000 000lbs bomb. The bomb we now have is at least 12,500 times larger in explosive power than the one that destroyed the Federal Courthouse in Oklahoma City. That is a pretty big bomb.
Anyway, it is just daydreaming and speculation on my part, I have nothing invested but a few thousand words of a story that may or may not get finished. Tomorrow the important stuff happens. The Cowboys play the Dog Assed Eagles.
October 7, 2006 11:34 PM | Reply | Permalink
The simplest answer is that I know of no published tests that even approach the problem, although the fundamental science isn't classified. At Texas City, there were two ships, the SS Grandcamp carrying 7700 tons of ammonium nitrate, which was the first to explode, and the SS High Flyer, carrying 900 tons and a couple of thousand tons of sulfur.
At Texas City, there was already a fire aboard the first ship, which they attempted to put out with steam in a confined space. That led to a thermal runaway condition, which is a more energetic explosion that you get from ANFO.
My intuition is that in the system you have described, without a great deal of work on a distributed detonation system, the whole mass would not go. Part of the factor would be the packing density, and the strength of the ship as a containment. There would be a big boom and a lot of damage.
Ammonium nitrate, even with additives, has a much slower detonation rate than, for example, TNT. This is actually useful for industrial or military engineering work, when your goal is to move earth rather than cut or shatter steel. Nevertheless, the slower the rate, the less likely it is that the entire mass will be subjected to a strong enough shockwave to cause detonation.
There's also a trend to modify ammonium nitrate fertilizer to be less explosive.
One of the hardest parts of nuclear weapons engineering is getting the high explosive detonation wave to propagate the way the designers want. There have been US military tests in the hundreds, up to 1000 or more tons of TNT equivalent, and the detonation system was extremely complex.
Just as is done with the chemical explosive systems for nuclear weapons, there would have to be supercomputer-level simulation to get a good idea what would happen.
I can't say why the links didn't work, but http://www.chemtrec.org/Chemtrec/AboutCHEMTREC/ is the 24/7 system for tracking hazardous material shipments. The Coast Guard is responsible for shipping inspections, and for ships such as tankers, bulk carriers, and LNG tankers, that inspection takes place in the waters a fair distance out from the port. It wouldn't be hard to tell the ship is loaded with ANFO or a more energetic mixture -- ANFO stinks of diesel oil. If the inspectors are using nitrate detectors, that would also pick it up.
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Howard
*equal opportunity offense to both extremes*
October 8, 2006 10:48 AM | Reply | Permalink
I noticed these Congressional Research Service Reports a couple of days ago while skimming available titles at the Federation of American Scientists' website. I haven't read them though, they may not be relevant.
There are probably other reports I didn't notice at the FAS archive of Congressional Research Service Reports on Homeland Security. CRS Reports are not usually too difficult to understand, they are, after all produced with the designated end-user in mind...
October 11, 2006 2:24 PM | Reply | Permalink
Thanks.
October 11, 2006 7:06 PM | Reply | Permalink