Would a liquid bomb on a plane be plausible?

A guy by the name of Perry Metzger wrote up an interesting analysis of the big terrorist plot that was thwarted in London recently in which he ponders how plausible the scenario might be:

First, a note of introduction. Until recently, I was a computer security guy, and as with many in my profession, the application of computer security analysis to non-computer security problems was increasingly interesting to me. Now, for reasons that don’t need exploring at this juncture, I’m back at school, studying chemistry, and I’m spending this summer in a lab doing organic synthesis work. Strangely, today I find my interests colliding.

So, I’m doing a bunch of reading, and I find the claimed method the “highly sophisticated” attackers came up with for bringing down airliners kind of implausible. I wonder if it could ever work in reality.

A disclaimer, I’m working entirely off of news reported by people who don’t know the difference between soft drinks and nail polish remover, but the information I’ve seen has the taste of being real. As near as I can tell, it is claimed that the terrorists planned to make organic peroxides in situ on board an airplane and use them to destroy the plane.

This seems, at least given my initial examination of the idea, implausible.

He then goes on to explain why and it certainly gives one reason to ponder if this isn’t all much ado about nothing. Which isn’t to say that there may not be binary liquid explosives out there that could be used to bring down a plane—I’m certainly no chemist myself—but it does appear that the chemicals the news reports are suggesting were being considered are at best impractical. Given the overly volatile nature of the resultant mixture the claims that iPods and other portable electronic devices would’ve been used to set off the explosion are simply ridiculous as all it would take is a good smack to set that crap off.

There are other open questions I have here as well. Assuming this is really what was planned, why are the airport security making people throw away their shampoo? If you open a shampoo bottle and give it a sniff, I assure you that you’ll notice concentrated sulfuric acid very fast, not that you would want to have your nose near it for long. No high tech means needed for detection there. Acetone is also pretty distinctive—the average airport security person will recognize the smell of nail polish remover if told that is what they’re sniffing for. Oh, and even if they used a cousin of acetone, say methyl ethyl ketone (aka MEK, aka 2-butanone), you’ll still pick up on the smell.

Which just reinforces the simple idea that it takes people trained properly on what to look for to add a reasonable amount of protection as opposed to all sorts of new gadgetry to sniff out explosives.

From there the note takes an interesting turn with Perry proposing any of a number of alternative means for terrorists to cause mayhem that wouldn’t be terribly difficult to pull off—none of which we’re currently doing anything to combat:

And now, on to the fun part of this note. First they came for the nail clippers, but I did not complain for I do not cut my finger nails. Now they’ve come for the shampoo bottles, but I did not complain for I do not wash my hair. What’s next? What will finally stop people in their tracks and make them realize this is all theater and utterly ridiculous? Lets cut the morons off at the pass, and discuss all the other common things you can destroy your favorite aircraft with. Bruce Schneier makes fun of such exercises as “movie plots”, and with good reason. Hollywood, here I come!

We’re stopping people from bringing on board wet things. What about dry things? Is baby powder safe? Well, perhaps it is if you check carefully that it is, in fact, baby powder. What if, though, it is mostly a container of potassium cyanide and a molar equivalent of a dry carboxylic acid? Just add water in the first class bathroom, and LOTS of hydrogen cyanide gas will evolve. If you’re particularly
crazy, you could do things like impregnating material in your luggage with the needed components. Clearly, we can’t let anyone carry on containers of talc, and we have to keep them away from all aqueous liquids.

And also….

Then, lets consider books and magazines. Sure, they look innocent, but are they? For 150 years, chemists have known that if you take something with high cellulose content—cotton, or paper, or lots of other things—and you nitrate it (usually with a mixture of nitric and sulfuric acids), you get nitrocellulose, which looks vaguely like the original material you nitrated but which goes BOOM nicely. Nitrocellulose is the base of lots of explosives and propellants, including, I believe, modern “smokeless” gunpowder.  It is dangerous stuff to work with, but you’re a terrorist, so why not. Make a bunch of nitrocellulose paper, print books on it, and take ‘em on board. The irony of taking out an airplane with a Tom Clancy novel should make the effort worthwhile.

So, naturally, we have to get rid of books and magazines on board. That’s probably for the best, as people who read are dangerous.

Indeed they are. Nothing more frightening than an educated mind, just ask the Pope.

Perry goes on to ask where it’ll all end. Will we get to the point where we’re not allowed to carry anything onto the plane and will have to fly naked after submitting to a full body cavity search? Even then, he suggests, that may not be enough:

If we’re looking for a movie plot, why not just get a sympathetic surgeon to implant explosives into your abdomen! A small device that looks just like a pace maker could be the detonator, and with modern methods, you could do something like setting it off by rapping “shave and a haircut” on your own chest. You could really do this—and I’d like to see them catch that one.

Go read the full essay. It’ll help put things into perspective.

Link found on Boing Boing.

19 thoughts on “Would a liquid bomb on a plane be plausible?

  1. Okay, it’s official. I’m never flying again.  wink

    Actually, I was with a group of people having a similar discussion the other night—we also brought up the surgery and body cavity issues (sick minds) and wondered about powders.

    What amazes me most is that no one has done/tried any of these things—most of which would be undetectable by any current screeening method. It seemed to us that it was virutually impossible to prevent a terror attack if someone really wants to do it. So, why not? Why have there been no attacks of any size in the US in the last 5 years??

    We can’t seriously believe that it is because (as Bush would claim) the new security methods are so very effective.

    (Interesting post, Les!)

  2. The day of the arrests a chemist was interview on TV to say that liquid bombs were feasible.  There are a number of liquids that will explode when mixed, or struck/thrown violently.  Many years ago on a kids science program (for all out UK readers- it was a Johnny Ball series) said that a stick of dynamite will explode of dropped.  The problem the terrorist would have is making sure it went off at the right time, hence having to be in cabin luggage.  These chemicles can be pretty corrosive, and will eat through plastic, so you need a glass or metal container.

    I don’t know if the electrical ban was to do with the liquids, but C4 plastic needs an electric current to go ‘bang’. Mates in the army have told me that they have seen it set light to, where it will burn like a coal. Apparently in a real war situation (where the QM doesn’t always count everything back) has been used to cook on. However it can be set off by a normal house battery.

    Surely all the authorities have to do is get some journos together and give a ‘re-enactment’ of what they thought was going to happen.

    On a personal note, one of the 7th July bombers lived opposite my mate, and one of the ones arrested thius time round lived in a road which I often call on as part of my job. I must have driven past his house a couple of hundred times

  3. LH: On a personal note, one of the 7th July bombers lived opposite my mate, and one of the ones arrested thius time round lived in a road which I often call on as part of my job. I must have driven past his house a couple of hundred times

    ‘They’ are everywhere. smile

  4. Just add water in the first class bathroom, and LOTS of hydrogen cyanide gas will evolve

    Which would not bring down the plane I guess, nor maybe kill all that many, with the ventilation system sucking it out? Not sure, but pretty sure it would be a dodgy one.

    On a sidenote, I remember reading an article in an investigative magazine (Austrian I believe) 15 years back, where the reporters managed to obtain chemical-weapon type gas by posing as a research lab towards the producer.

    It is dangerous stuff to work with, but you’re a terrorist, so why not. Make a bunch of nitrocellulose paper, print books on it, and take ‘em on board. The irony of taking out an airplane with a Tom Clancy novel should make the effort worthwhile.

    The fact is that most of these explosions would probably not be strong enough to doom the plane. Google around the net, and you will find some pictures that show that even with a hull-breached cabin, most planes can still fly.

    Why not just get a sympathetic surgeon to implant explosives into your abdomen!

    Again, the amount of mass probably would not be enough. Chemical scans also MIGHT pick it up.

    What amazes me most is that no one has done/tried any of these things—most of which would be undetectable by any current screeening method. It seemed to us that it was virutually impossible to prevent a terror attack if someone really wants to do it. So, why not? Why have there been no attacks of any size in the US in the last 5 years??

    Which shows you that all of these are probably NOT nearly as easy as they are made out to be.

    But at the end of the day, the big mistake of the liquid bombers was not their intended modus operandi – their mistake was not heeding the old proverb: Three people can keep a secret if two of them are dead.

    ‘They’ are everywhere.

    Fittingly enough, thats what both sides would like you to think.

  5. even with a hull-breached cabin, most planes can still fly.

    What they can’t do is fly at 30,000 feet. 800 grams of C4 (approx 1 1/2lbs – less than a bag of sugar) will breach the thin hull of a 747 making a big enough hole to cause decompression.  By the time it has finished falling to a height where it can fly it will be too damaged and out of control to be flown.

    Why not just get a sympathetic surgeon to implant explosives into your abdomen!

    Also you’d need to be sitting close to the outside, and you would need a FAT suicide bomber, to be able to hide enough. the 800g has to be fairly close to the edge.

    ‘They’ are everywhere.
    Fittingly enough, thats what both sides would like you to think.

    Just commenting I don’t think many posters here have parked outside a suicide bombers house.  The bombings have lead to an increasing gulf between British Muslims and the rest of Britain.  On one hand they are seen as insular- ghettoisation is seem as a problem in ‘engagement’.  A recent survey for a program called ‘What Muslims want’ showed that a significant minority rejected western liberal ideas, some even wanted Sharia law in the UK.  This was often young Muslims, who were born here, but less liberal that their immigrant parents.  Please note- I am not saying that there is some Muslim revolution about to take over, just that a minoriry wanted a move to some form of Islam.

    The problem is many perceive a islamophobic Britain as shown in thisanalysis that is not true.

    In addition right wing commentators say that ‘We don’t stop and question white men in tweed suits, because they are not the bombers. While there are muslim bombers then it is muslims who will get stopped’.

  6. Keep in mind, folks, that you don’t necessarily need to cause the plane to crash to effectively spread terror. I’m pretty sure that someone with an implanted bomb inside him would still do a fair amount of damage to several rows of people immediately around him when he blew up and would leave some awful emotional scars on the survivors.

    A handful dead and a couple of hundred with some serious emotional trauma can still be very effective.

  7. you don’t necessarily need to cause the plane to crash to effectively spread terror

    Did they ever get a clue who sent these letters laced with Anthrax?

    We should be grateful that so far, the bad guys try to show off their big swinging dicks instead of inflicting the most damage with the least amount of effort.

  8. Nope, the anthrax killer has never been caught. Much like Osama, the Bush Administration decided to just forget he ever existed.

  9. By the time it has finished falling to a height where it can fly it will be too damaged and out of control to be flown.

    What makes you think that? As far as I understand, the depressurization would not be ‘explosive’ (though it might certainly seem so to your eardrums if you sit inside). Air would rip out of the plane until pressure is equalized, yes (but that would not tear it to shreds, or impact the control surfaces/wings, unless the bomb WAS pretty big or pretty well situated).

    But why should that cause a crash? Pilots would be least affected by the pressure drop in the cabin, and most likely to have masks on by the time the cockpit depressurizing would have reached dangerous levels.

    At least, that is how I see it (I have no direct technical experience of airplanes or bombs). One of my best friends is an aircraft mechanic though (on the big ones, too), and I will ask him. May take a while though.

    Nope, the anthrax killer has never been caught. Much like Osama, the Bush Administration decided to just forget he ever existed.

    Isn’t that a bit too much knee-jerk, Les? Would you prefer them to look into our mail too (oh forgot they already do*), because there might be Anthrax in there?

    (*But I realize that in these days, sending old-fashioned papermail is probably less likely to be intercepted that email…)

    No, really, it is pretty hard to find a mad killer who works through the mail only, especially once he stops.

  10. Ingolfson writes…

    Isn’t that a bit too much knee-jerk, Les? Would you prefer them to look into our mail too (oh forgot they already do*), because there might be Anthrax in there?

    Nothing knee-jerk about it. It’s a simple fact that the anthrax killer has never been caught. From the Wikipedia entry on the topic:

      As of 2006, the anthrax investigation seems to have gone cold. Authorities have traveled to four different continents, interviewed more than 8,000 individuals and have issued over 5,000 subpoenas. The number of FBI agents assigned to the case is now 21, ten fewer than a year ago. The number of postal inspectors investigating the case is nine.

      The FBI and postal inspectors are in the process of preparing an internal report reviewing the history of the investigation. The report will include a list of “persons of interest” and the latest on the scientific tests used on the anthrax material. Investigators still have not determined the lab used to make the anthrax.

      A “person of interest”

      The Justice Department has named no suspects in the anthrax case. Although Attorney General John Ashcroft labeled Dr. Steven Hatfill a “person of interest” in a press conference, no charges have been brought against him. Hatfill, a virologist, has vehemently denied he had anything to do with the anthrax mailings and has sued the FBI, the Justice Department, John Ashcroft, Alberto Gonzales, and others, for violating his constitutional rights and for violating the Privacy Act. He has also sued The New York Times and its columnist Nicholas D. Kristof and, separately, Donald Foster, Vanity Fair, Reader’s Digest, and Vassar College, for defamation. (The case against The New York Times was initially dismissed, but was reinstated on appeal. Nicholas Kristof has been dropped from the suit. Hatfill’s lawyers believe the Privacy Act was violated and continue to question journalists who have reported on their client.

    There’s also a brief news item at the Mercury News that reiterates this fact.

  11. Nothing knee-jerk about it. It’s a simple fact that the anthrax killer has never been caught.

    What I meant was: not being able to find the anthrax terrorist (and the matter eventually dropping out of the news and even from the priorities of the authorities, seeing that he does not seem to be active anymore)…

    …is not directly comparable in my opinion to the US administration pretty much giving up on finding Osama, while using his actions to justify and cheerlead for the WAR. ON. TERROR.

  12. Never claimed it was, just that, like Osama, neither has been caught and there doesn’t appear to be much emphasis to bother trying at this point.

  13. Just finished Richard Clarke’s “Against All Enemies”. Clarke was head of CSG- Counterterrorism Security Group- in the White house in the 90’s, and he details of out of Reagan, Bush 1, Clinton and Bush 2 only Clinton took terrorism seriously. (though obviously the cold war kept a cap on it with Reagan, but incidents such as the Lockerbie bomb were mishandled).  He is especially Critical of Dubya, whose administration were completely focused on Iraq from day one, dismissing al Qaeda as not important.

    This extract is from Chapter 4 Terror returns.

    {Ramzi Yousef} was planning to blow up U S Airliners in the Pacific … using liquid explosive, assembled in the bathroom… The Filipinos found some of the bombs, but not all.

    BEFORE WE GET LOADS OF POSTS SAYING NOT POSSIBLE (and I admit I have no idea of the chemistry) does anybody know if there had been any demonstration showing how a liquid bomb could be made in an aeroplane toilet, with items that in less secure times could be taken on board.

    FYI The IRA lorry bombs were made of fertiliser (from garden centres etc), and sugar.  And the police taught me how to make one…

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