Debating the feasibility of an in-flight liquid bomb

A UK court finally heard evidence about the bizarre liquid-explosive plot hatched in 2006 by some fairly unrealistic suicide bombers, the origin of the global ban on taking liquids through aviation security checkpoints. The plan? To mix Tang and peroxide in Lucozade bottles and make airplanes go boom. Ever since the plot first came to light, chemists and explosives experts have been highly skeptical of it working, and the TSA and UK authorities have blithely insisted that they believe it could come true.

Now, readers of Bruce Schneier's security blog are invited to weigh in on the feasibility of such a scheme, given the information that just emerged in court:

The court heard the bombers intended to use hydrogen peroxide and mix it with a product called Tang, used in soft drinks, to turn it into an explosive.

They intended to carry it on board disguised as 500ml bottles of Oasis or Lucozade by using food dye to recreate the drinks' distinctive colour.

The detonator would have been disguised as AA 1.5 batteries. The contents of the batteries would have been removed and an electric element such as a lightbulb or wiring would have been inserted.

Link to Schneier's blog, Link to Daily Mail article


  1. and that’s the reason i have to hand over my toothpaste at every checkpoint? ffs.

    man, wait til they see what i can do with this bottle of diet coke and a few mentos.

  2. That’s it? Sheesh.

    Would anything remarkable actually happen if you mixed Tang and hydrogen peroxide?

  3. Wow, these guys must have been in my 3rd grade class when rumors were flying about Mikey from the Life cereal commercials dying from eating Pop-rocks and drinking Coke simultaneously.


  5. I work in chem research and did some experiments with 80% Hydrogen peroxide when these guys were first arrested.
    We didn’t know about the tang but used some things that would decompose the peroxide even faster than Tang.
    Our findings were that these guys wouldn’t have been able to carry on the amount of peroxide needed for a bomb.
    It could have stated a small fire though.
    Even some of the souped up peroxides we have in the lab only burst into flame. the combustion is just not fast enough.
    If terrorists wanted to kill lots of people they would and could so easily.
    A hundred dedicated terrorists could kill thousands of people a day and wouldn’t be caught for months.
    I won’t post any ideas but I am sure you could think of a dozen ways to kill people at random.
    People are not being killed so the terrorist thing is WAY over hyped.
    The terrorists score a point every time we lose some Freedom. Fear is the mind killer.

  6. This would be nothing compared to 100 g granulated metallic potassium under oil inside a couple dozen condoms up the butt. Water is readily available on planes.

  7. My suspicion about all of this is that it’s about weight. The airlines have clung to it for the cumulative fuel savings. Which might explain the open trash cans full of “potentially dangerous” liquids next to the security line.

  8. you know, I’d like to see someone hose down a flight with a bottle of Diet Coke (purchased post-checkpoint) and a roll of Mentos (purchased post-checkpoint) simply to prove that you can make a big mess of the plane regardless of whether you allow liquids through security or not. And that’s about all you can do.

    But srsly, Tang? That stuff is toxic by itself.

    Air travel is getting surreal. My mate’s flight home yesterday was delayed by 3 hours because there was a really bad “fishy” smell on the plane. The pilot took a good whiff and rejected the plane, so they had to get another one.

    I just imagine a suitcase with a big fish skeleton in it going unnoticed across the X-ray screen :)

  9. Maybe they should have used some FULMINATE OF MERCURY!

    (Ob. *Breaking Bad* content.)

  10. According to the previous sensationalist newspaper article I read, they were planning to mix a strong cyanide solution and some acid rather than use explosives — a plausible attack although I don’t know whether it’d get the pilots.

    The BBC is reporting 6/8 had recorded suicide/martyrdom videos —

    In the UK it’s a crime to plan attacks like this even if you get caught before you go through with it – so the accused do have a case to answer and it’s right they’re on trial.

  11. Yes you may all laugh at a bomb made of peroxide and Tang, but liquid explosives on planes is not an un-tested idea.

    “On December 11, 1994, Yousef built another bomb, which had one tenth of the power that his final bombs were planned to have, in the lavatory of an aircraft. He left it inside the life jacket under his seat, 26K, and got off the plane when it arrived in Cebu. …. Yousef had set the timer for four hours after he got off the aircraft. The bomb exploded while the aircraft was over Minami Daito Island, near Okinawa, Japan. A Japanese businessman named Haruki Ikegami was killed after the bomb detonated.”

    Form this Wikipedia entry.

  12. Daily Mail, sigh.

    The Times:
    General Overview
    Airline bomb plotters made martyrdom videos, court hears
    Airline terror suspects ‘converted empty flat into bomb factory’

    The Guardian
    Details of the plot
    Details of the bombs

    The Independent

    I mean, it’s really not that hard. Why not try bookmarking or Your own life will be significantly better for it, and by helping to reduce The Mail‘s source of oxygen, you’ll be helping to improve the quality of life for everyone else as well.

  13. The Guardian has a rather better writeup of the alleged plot. Regardless of whether this would actually have worked, it seems on the face of the evidence being presented that those on trial believed it would work. And that’s all the prosecution have to prove; under English criminal law, you can be guilty of attempting a crime or conspiring to commit it even if circumstances were such that you could never have succeeded.

    As to the actual feasibility, at the time this was first reported I asked the opinion of a colleague of mine with an MSc in explosives engineering and experience in bomb disposal. He felt that it was certainly possible to make a DIY liquid explosive bomb, but had doubts on how feasible it would be in practice. It’s certainly not the case, as I heard someone loudly opining once, that “liquid explosives would violate the laws of physics”; that would be news to anyone who’d dealt with nitroglycerine!

  14. I wanted to take a picture of the dedicated “unopened beer and wine only” bin at the Pittsburgh airport, but was afraid of the gorrilla like guys being told what to do by nerdy beauracrat types.

    I mean, surely they weren’t going to save the unopened beers for anything. They could have high explosives in them!

  15. JS7A: 100g of potassium is not going to be able to significantly damage an airplane. It gets pretty fizzy and generates some hydrogen, but 100g K = 2.56 mol, which means 1.28 mol H2 generated. (That’s about 8.3 gallons at ordinary pressure and room temperature). When H2 burns to form water vapor, 235kJ/mol are released, so in this case 300kJ are released. If you could trap all the H2 and combust it all it once, it could be significant, but you can’t – it doesn’t combust fast enough – and you’re much more likely to just end up with some nasty chemical and thermal burns in your rectum if your condom breaks, a bad case of gas, and to be body cavity-searched when that 100g of METAL sets off the metal detector in airport security.
    BTW, 100g of potassium, a low density metal, would occupy 112 mL, a fairly large plug to put in your rectum. I wouldn’t recommend it.

  16. Ok, so the quote above says they were going to gut at AA and “an electric element such as a lightbulb or wiring would have been inserted.” Doesn’t that seem like making pointless, suspicious work for yourself? Why not just bring a frickin’ small flashlight with you?

  17. Side thought: is bringing your Sprite past the security checkpoint a civil liberty? (article tags)

  18. Cory,

    I’m bitterly disappointed that you didn’t title this post Tang Linked To Terrorism.

  19. I’m less afraid of a bomb blowing up my plane than I am of a gas-chamber style attack while in flight. Introducing poison gas into an air-tight cabin with rapidly recycling air and no exit…gives me the creeps.

  20. #24,
    Oxygen (the result of peroxide decomposition) is not THAT poisonous – certainly diluted by all the air on the plane it would not be a problem. Now if you got HCN onto the plane – that could be a problem.

  21. Lufthansa gives, and Lufthansa takes away.

    A couple months ago flying through Frankfort. I took the 0.2 liter bottle of water, unopened, because I wanted to drink it later. In the airport, they took it away from me as a hazard. Go figure.

    I’m calling on all travelers to call the authorities regarding the bins of potential bombs that TSA personnel are stockpiling in airports, right next to where they force hundreds of people to congregate.

  22. #24: The cabin air in an airliner is purged and refreshed every few minutes (I can’t recall the exact requirement for certification). It is not recycled.

  23. OK, leaving aside discussion of whether or not a ‘liquid bomb’ is theoretically possible using nitroglycerin or something, is there anybody with a strong engineering or chemistry background that thinks the synthesis of Hexomethane triperoxide in an airport bathroom is feasible?

    And even if you assume their highly-dubious and short-on-details plan for synthesizing HMTP in an airplane bathroom is possible, um, then you can determine whether or not a liquid can be allowed to come on board with a simple ‘sniff test’. Anybody with concentrated peroxide disguised in some other container gets arrested, pretty simple.

  24. JS7A: Impressive, but not going to take down an airliner. Go ahead and stick it up your butt if you want, but you won’t get far.

  25. It doesn’t really matter whether the UK example would have worked. If you know that people are working on liquid attacks – even if the only ones you catch at it are undereducated nutters – it makes sense to restrict liquids at screening. Someone else out there will be smarter.

  26. hookays Americans! We are forgiving up the Khemikal bombas. Is now suicide plague bearers!

    Screen that, Boosh-kissing no Allah-liker guys!!

  27. Argh…

    If you read the story carefully, you note that the HTP wasn’t mixed with Tang for the explosive, but with “other chemicals which the Daily Mail is not naming”. Go down to the bottom, sixth para from the bottom.

    The dye and tang were to disguise the mixture.

    The various discussions about making something in-flight with HTP are a red herring. There are chemicals available which when mixed with sufficient concentration peroxide form a cap-sensitive or more sensitive high energy brissant liquid high explosive. Pre-mixing and carrying it on in that form was the risk.

    This is not new – people aware of the mixtures have been trying to get airline security experts and the screeners to look for these things for years before 9/11.

  28. Dear Mr. Herbert:

    It’s clear you know what you are talking about.
    In your opinion, is there any way on earth to keep explosives off aircraft?

  29. Peroxides are powerful oxidizers. The one you buy at the drug store is very dilute (2.5% concentration). Industrial peroxides are very dangerous even without the Tang and require special containers and special handling. High test peroxide (80-90% concentration) is used as a component of rocket fuel. In contact with a catalyst, it decomposes rapidly into a high temperature mixture of steam and oxygen (which in turn can burn anything in sight). The Bell Rocket Belt used hydrogen peroxide as a fuel. Hydrogen peroxide leaks from torpedo propellant have been blamed for the sinking of several submarines. Spilling high test peroxide on a flammable substance (like a fine powder, plausibly Tang) can cause it to burst immediately into flames — flames that rapidly grow worse due to the free oxygen liberated by the reaction. It was part of the 2005 London underground bombs, which failed to explode.

    Fortunately, the only way to really get it if you aren’t a corporation or a government is to take low concentration peroxide and distill it. This is extraordinarily dangerous and more likely to kill the distillers than anything else.

    But even 10% pure peroxide gives off enough oxygen from decomposition that it can spontaneously detonate at temperatures above 70 degrees. The vapors can form contact explosives when reacting with hydrocarbons such as grease. Spilled on clothing, it will evaporate water until the concentration reaches sufficient strength to burst into flames. Even medicinal concentrations can be dangerous. Swallow it and it will release enough gas to cause internal bleeding.

    Tang is funny. Peroxide is dangerous stuff.

  30. You can buy large quantities of 90% peroxide if you know where to go. You can buy 70% in 55 gallon drums, or tanker car loads worth, with no more paperwork than the billing. It’s not really a particularly well guarded chemical in the US, and is used in hundred thousand ton a year quantities in many industries.

    Can we keep bombs off aircraft? No. Liquid explosives in carry-on containers was at the top of the list of low-hanging fruit things to try and prevent, if you seriously want to prevent them. But you can’t entirely prevent them.

    The list is rather long. A wide variety of things can be made to explode with enough energy to do fatal damage to an airliner. They can be disguised or carried on in a wide variety of manners. There are plenty of explosives with no nitrogen (the usual detection mechanism) and with density outside the usual range looked for with most X-ray equipment. There are places they can be put that nobody looks, and myriad ways to bypass security checkpoints that are extremely poorly guarded today.

    I travel on airline flights. I do so because even though I know more ways to bring them down than I can conveniently count, I very much don’t want to, and the odds that someone else is going to try seem to be far far lower than the odds that someone will kill me in a fatal auto accident getting to or from the plane. The odds that if they do try something they’ll try something dumb rather than clever are high. A large portion of suicide bombers (airline and otherwise) are detectable by mere observation, which TSA is trying to learn from the Israelis. There’s other stuff which helps reduce their odds of success.

    So the risk is low.

    But not zero, and there’s no credible way to prevent the long tail of the risk function from being there. It’s going to eventually happen again, when by random luck eventually a competent enough bomber with competent enough operational skill gets something on board. It may be a decade or more down the line. But it will happen again.

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