Getting confused on the size of the bomb [cleared up, and then muddied again]
I've been trying to reconcile the different weights and measures being bandied about since yesterday. I'm having problems.
The alleged terror plot uncovered in Toronto involved 3 tonnes of ammonium nitrate.
A tonne, or a metric ton, is 1000 kilograms, or 2,204 pounds. A short ton is 2000 pounds, or about 0.91 metric tonnes. So conveniently, a short ton and a metric tonne are essentially interchangeable.
Now the bomb that destroyed the Alfred P. Murrah federal building in Oklahoma City in 1995 weighed 5000 pounds, or 2300 kg, or just over two metric tons (according to Wikipedia, and a similar number is quoted in other sources). It was a mix of ammonium nitrate and the racing fuel nitromethane.
During the news conference, RCMP Assistant Commissioner Mike McDonell stated that the Oklahoma bomb contained 1 metric ton of ammonium nitrate.
So that would mean a 50-50 mix of ammonium nitrate and fuel oil. But that's not how you make an ANFO bomb. The real mix is closer to 94% ammonium nitrate and 6% fuel oil. You don't need much fuel oil because the fuel oil just starts the reaction (the fuel coats the pellets in the mixture, and ignites them -- trace amounts of other materials can enhance the reaction).
Maybe there are other legitimate ratios (I'm not a bomb expert or a chemist), but I'd be surprised if any approached anything close to 50-50.
Using the 94% ratio and the size of the overall bomb, and ignoring the RCMP stated amount of ammonium nitrate used, the Oklahoma bomb used 4700 pounds of ammonium nitrate, or 2.1 metric tons. That means the size of the bomb being imagined by the Toronto terrorists was somewhat larger than the Oklahoma bomb, but not as large as suggested at the news conference. Closer to 50% larger, and not 200% larger.
Maybe there is something missing here. I could be wrong about the ANFO ratio used by Timothy McVeigh. Or maybe the overall size of the bomb is being misquoted. Or maybe someone who has the details the RCMP used to prepare the news conference can verify the numbers and show us the math.
I don't want to say the alleged plot was somehow less horrifying, but if you are going to make comparisons, make sure they are fair ones.
Update: I found a recipe that splits the explosive ratios by weight as 36% ammonium nitrate, 55% potassium chlorate, and 9% fuel oil. If we use that recipe, and the number quoted by the RCMP, the Oklahoma bomb consisted of 1 metric ton of ammonium nitrate, 1.5 metric tons of potassium chlorate, and a quarter metric ton of fuel oil. That adds up 2.8 metric tons, which is about the size of the Oklahoma bomb.
The Toronto bomb therefore would have been 3 metric tons of ammonium nitrate, 4.6 metric tons of potassium chlorate, and 0.75 tons of fuel oil -- a total of 8.3 metric tons of explosives.
If that's true, these terrorists were planning to create a much more sophisticated and devastating bomb, or more likely series of smaller bombs -- three or four times the size of the Oklahoma bomb, depending on the specific recipe they were going to use. Just as indicated at the news conference.
On the other hand, this sort of bomb is harder to put together. These guys were getting advanced advice.
Glad I got that cleared up -- I think. I guess I'll keep an eye out for confirmation of the sort of bomb these guys are alleged to have been planning to mix.
Another update: Robert McLelland made this point on Andrew Coyne's blog where this discussion is also taking place. The Oklahoma bomb was a homemade Kinepak explosive, meaning a mixture of ammoniun nitrate and nitromethane. I've spent some time lurking around creepy homemade explosive message boards, and the "standard" ratio is 40% nitromethane and 60% ammonium nitrate. The testimony of Terry Nichols confirms that these were the components in use, but he was not clear on the ratios.
Using these numbers and the accepted weight of the bomb as 5000 pounds, the amount of ammonium nitrate in the bomb was 3000 pounds, or 1.4 metric tons. It's a bit off from the number reported by the RCMP, though not by much.
From what I gather on these boards, everyone who plays with explosives recreationally has their own favourite recipes anyway. So it's possible that McVeigh used 1 metric ton of ammonium nitrate and a somewhat larger amount of nitromethane than the accepted standard ratio.
I've learned a lot from this piece.
Now the RCMP made the point of comparing the planned Toronto bomb mix with the Oklahoma bomb by comparing the amount of ammonium nitrate in the possession of this group with the amount of ammonium nitrate used in the Oklahoma bomb. If I've learned anything from this exercise is that the comparison is meaningless if the underlying formula is different. Many different bomb recipes use ammonium nitrate. The amount used might constitute anything from as low as 35% of the total weight of the bomb, all the way up to 95%. So a stockpile of 3 metric tons of ammonium nitrate could yield from 3 to 9 metric tons of high explosive.
But then each formulation has different properties. From what I can tell, some of those more complicated ones give you both more material and more destructive power, but at the cost of having to acquire more components (a risky propositiion for terrorists trying to remain unnoticed).
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Comments
Imagine how easy it would be to place these explosives into a truck and place this truck at the intersection of Bloor and Young at rush hour. What would be the damage to the surrounding buildings? The subway below? Imagine.
Posted by: Michael Hammer at June 4, 2006 02:50 PM
Steve, do we really want to be broadcasting these kinds of chemistry information right now? I realise this is all over the web, but let us not give anyone any ideas, shall we? At least make 'em work for it eh?
Posted by: The Phantom at June 4, 2006 04:19 PM
Let's not get hysterical, Phantom.
There are 250 000 bomb recipes out there.
Posted by: A&W at June 4, 2006 04:26 PM
You are right Steve things don't add up.
The whole thing looks like it was made for TV.
A bag of fertilizer with the RCMP note that it wasn't really confiscated as part of the bomb building supplies.
A picture of a cell phone, door bell, soldering iron and multimeter made me think of McIver.
And then to include a gun confiscated in a unrelated incident from a year ago makes me think that it is budget time at CSIS.
Somebody has an agenda that includes trying to scare the shit out of us so that we become quivering blobs willing to suspend all disbelief for the sake of imagined security.
Posted by: Glen at June 4, 2006 06:13 PM
Apparently the terrorists lawyer thinks the whole scary, hidden agenda was for the police to make up a terrorist scare, so that the Supreme Court will authorise a kneejerk crackdown down on terror. Hey, sounds like a real cool plan to me, but I wonder if Beverly McLauchlan will get as upset about this as she did about that Conservative MP's comments.
Lawyer Rocco Galati, who represents two of the men arrested on Friday, agreed that the timing of the arrests looked suspicious, as was the massive show of force Saturday when several of the suspects appeared in court. "I'm not shy to say that I think this whole thing's been timed, including the massive show of force, a little bit more than a week before the Supreme Court is to hear the appeals in Ottawa,ā€¯ he said.
Posted by: neo at June 4, 2006 08:24 PM
3000 pounds of explosives in Manchester England 1996 took out the following
On Saturday 15 June 1996, at a peak shopping time on Father's Day, a 3,000lb IRA bomb exploded in Manchester, injuring more than 200 people and ripping into the fabric of the city's main shopping centre. In a state of shocked disbelief, police had begun clearing people from the area some 40 minutes before the blast; fortunately, several telephoned warnings had been issued to newspapers, radio stations and to at least one hospital in Manchester an hour before the blast. Newspaper offices in Dublin and Belfast received similar warnings.
An army bomb squad employed a robotic anti-bomb device to check an illegally parked Ford van, which had been recorded by several closed circuit security cameras in the city, when the bomb exploded.
Manchester's ambulance services counted 206 injured people. Most injuries were sustained from falling glass and building debris. In the immediately ensuing chaos, ambulances and private cars were used to shuttle victims to local and regional hospitals.
Local authorities had to close Victoria and Piccadilly railway stations for several hours and to seal off the city centre. The evacuation of shoppers immediately took place from the Marks & Spencer's department store, which was directly at the centre of the site, outside which the lorry-bomb was parked.
Initially, the evacuated staff and shoppers stood outside, right next to the bomb, but when the emergency services realised this they shunted them to the nearby Victoria Station. Why Manchester city centre was targeted by the IRA is uncertain, but it later became clear that the cause probably lay in the breakdown of the IRA "ceasefire" in the light of lack of progress with the British Government's ongoing talks about a permanent peace settlement in Northern Ireland.
It was estimated that up to 50,000 square metres of retail space and nearly 25,000 square metres of office space have subsequently needed to be reconstructed.
We`re told they had 6000 pounds (see link)
Lets take this very seriously.
Posted by: Floyd Low at June 4, 2006 09:25 PM
Terrorists are not terrorists until proven so in court. Can we please adjust our language around here to reflect that fact?
Innocent until proven guilty, remember?
Aaron
Posted by: Aaron at June 5, 2006 06:37 AM
"Terrorists are not terrorists until proven so in court."
Let's not forget this important fact! Also, the color red is not to be described as red until verified by a qualified scientist with a properly calibrated spectrophotometer. A suicide bomber can never be described as a radical Muslim until all the neighborhood Jewish grandmothers are cleared of the crime by the local police chief. Want more examples?
I'm totally nauseated by this liberal brainwashing which has perverted Canadians.
Posted by: Alienated at June 5, 2006 07:39 AM
Chemistry isn't the issue, Angry. Home-grown jihadists raised in a country that advertises itself as the anti-U. S. is the focus. Time to change the game plan.
Aaron, the arrogant semantics lesson telegraphs a craven, collaborative character. Bombs away.
Posted by: angryinthecornbelt at June 5, 2006 08:47 AM
Wow, I've just learned that due process before the law is "liberal brainwashing [that] has perverted Canadians" and "arrogant semantics." The last thing this country needs is cowards attacking our civil liberties because they're scared of an alleged prevented terrorist attack.
Posted by: Greater Toronto Area Conservative at June 5, 2006 09:40 AM
It was more than a breadbasket.
Posted by: Shaken at June 5, 2006 07:01 PM
"I'm totally nauseated by this liberal brainwashing which has perverted Canadians."
Actually thinking for myself is something I take pride in doing. Consider giving it a shot, as opposed to say, swallowing this media circus for what is, fear-mongering.
The big boys in blue got their terrorists so hooray for policing, increased "security", prison sentences, and officers on roofs of government buildings with assault rifles in hand. Due process, why bother? They're just going to be found guilty anyway.
What a crock of shit.
Aaron
Posted by: Aaron at June 6, 2006 06:42 AM
Can someone help me. At first, police said they had three tons and showed a bag "for illustration". Now, they say they were planning to acquire tree tons. How much did police actually find?
Posted by: EM at June 6, 2006 10:27 PM
I'm a little late to the party, but this WorldNetDaily report estimates that McVeigh's bomb was about 3 tons. He certainly didn't need that many barrels for 1 ton of fertilizer.
http://worldnetdaily.com/news/article.asp?ARTICLE_ID=22963
Posted by: RJM at June 9, 2006 02:44 PM
 
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