"Wow. Moth balls. So, what's for dinner?" "Plastique."

This MetaFilter post reminded me that just owning a common Casio wrist watch is now being used as evidence of terroristic intent. The post links to this Seattle Post-Intelligencer article, in which a retired FBI agent points out that this "evidence" is every bit as preposterous as you'd think.

That model of watch may be popular for use as a bomb timer, but there are hundreds, if not thousands, of other watches - and non-watch timer devices - that'd work just as well. The Casios show up so often merely because Casios are easy to find, and cheap.

Similarly, most terrorists have eaten bread on several occasions before committing their crimes. So if you find some bread in the kitchen of a guy called Achmed... do I have to draw you a picture, people?

At the end of the article, though, the ex-FBI guy goes on to say "You give me a half-hour in a supermarket and I can blow up your garage."

It's great to point out that bad people cannot be prevented from doing bad things by banning certain commonplace but allegedly magically dangerous items. But I think claims like this don't help. The idea that any kid can find a recipe for an honest-to-goodness building-smashing bomb on teh internets and be blowing up their school tomorrow is a common one, and it fans the fire of unreasoning fear that's screwing the Western world up so badly.

I'm ready to be corrected, but I don't think it is, actually, possible to build a proper bomb out of stuff from the supermarket. No matter how easily Kyle Reese did it in The Terminator.

(Note that the above does not apply if your local "supermarket" is a Wal-Mart that sells guns and ammo.)

I think the closest you could get to a genuine "supermarket bomb" would be fertiliser (if your supermarket actually has some fertiliser product that's reasonably pure ammonium nitrate) and motor oil. But then what're you going to use as an initiator? I don't remember seeing a "Blasting Caps" aisle the last time I was in the supermarket.

The most feasible initiator would probably be the dangerous but widely-used TATP, which you can almost make from supermarket supplies.

The problem with TATP - and HMTD too; HMTD is what the rather implausible "liquid bombers" apparently intended to use as their main explosive - is that you need concentrated hydrogen peroxide to make it. I don't think there's any way to concentrate "drugstore" peroxide - which tops out at about 6% concentration - that's easier than synthesising peroxide (which is hardly a complex molecule, after all) from scratch.

Apparently the unsuccessful London July 21st bombers thought they could concentrate peroxide by just boiling it down, but I think that's hopeless. Hydrogen peroxide will constantly decompose into water and oxygen even at room temperature, after all; the hotter you make it, the faster that happens, leaving you with nothing but water. Perhaps you could concentrate hair-bleaching 6% peroxide a bit by simmering it, but you need to get it up past 50% concentration to make it useful for whiz-bang sorts of applications. That's just not going to happen on the stove.

(The result of the July 21st bombers' incompetent work was, of course, that none of their bombs went off. So much for "supermarket terrorism".)

There are various other teenage-mayhem sorts of possibilities with supermarket ingredients. You could make rather nasty gas - though not any sort of explosion - with ammonia and bleach. Pool chlorine plus anything acidic will give you chlorine gas; that's poisonous too, and if you cork the mixture up tightly the bottle will explode, though not with enough force to damage anything bigger than a badly-built doghouse. And there are umpteen different supermarket flammables with which one could simply burn a garage down.

But I don't think that even if you visited the supermarket and then the hardware store, you'd be able to make anything more deadly than a pipe bomb full of match-heads. Which you wouldn't want to go off under your chair, or anything, but which isn't going to blow away a garage either.

If all you've got to work with is off-the-supermarket-shelf ingredients, I think the most impressive result you can hope for is that achieved by that schmuck who hoped to destroy Glasgow Airport by setting his Jeep on fire.

Some or all of the above has been independently discovered by every 14-year-old boy who's ever downloaded the notoriously incompetent "Jolly Roger's Cookbook". The take-home message for them, and for everybody else, is simple:

Yes, ordinary household products can be dangerous, as has been discovered by many people who mixed ammonia and bleach and then woke up in hospital. Or didn't wake up at all.

But there's no reason to wet yourself in terror if you come home early and find your kid mixing drugstore peroxide and nail-polish remover in the kitchen.

People who intend to commit crimes of violence via a method that can't possibly work - "I'm going to kill the Prime Minister using my powers of mental telepathy!" - should still be investigated, because it's possible that after trying the telepathy thing for a few weeks, they'll just go and buy a rifle.

But worrying about terrorists making bombs out of groceries is foolish.

Explosives are actually difficult to make, and domestic terrorists in the Western world are (a) clearly not very bright and (b) so rare that even if their idiotic schemes worked every time, you'd still be far more likely to die because you fell off something.


22 Responses to “"Wow. Moth balls. So, what's for dinner?" "Plastique."”

  1. Red October Says:

    If I wanted to make a nice explosion from the supermarket I'd see about flour. As far as I understand, any fine powder will explode in the air, and some are better than others (like, say, powdered aluminium), but there have been some pretty good explosions from flour mills here and there. I'm not sure, but I'd be willing to bet that if the supermarket was of the sort that vended beverage alcohol, and if Everclear were among the types offered, that that too could lend a hand.

    However I think the point is that while it's quite easy to make something dangerous from normally docile goods, that it's quite another thing to make something that crosses the line from "Dangerous thing" into "Truly effective weapon of war" -witness most forms of biological warfare. Most diseases are extremely difficult to weaponize and even doing so is of dubious value. So yeah, you can make something that goes "Boom" with relative ease. Probably even a reasonably destructive "Boom" at that, but not a "Level a major govermental structure" sort of "Boom".

  2. Rask Says:

    I'd second flour. (I'd first it, but the previous commenter beat me to it.)

    All you'd need is a small charge to disperse it in the garage, and a second charge to ignite it. Mind you, the volume of the garage would have to be known or well estimated in order to get the correct fuel/air mixture happening.

  3. Daniel Rutter Says:

    > All you’d need is a small charge to disperse it in the garage

    Well, yes, exactly. A small charge of what? Harsh language :-)?

    And getting fuel-air explosives to actually work is, itself, less than completely easy. The baby flour bomb that just fires a Milo tin lid to a great height is simple, but scaling it up is not.

    Just because anybody can make a hilarious flame-burst by tossing non-dairy creamer into a flame (see that recent MythBusters) does not mean that you can "weaponise" the phenomenon without an awful lot of rather-noticeable-to-the-neighbours trial and error.

  4. Popup Says:

    When I was a kid we used to make bombs out of water.

    If you split it into hydrogen and oxygen you get a fairly explosive mixture. We used .5l plastic drink bottles, and the explosions were fairly memorable (We made electric 'starters' out of lightbulbs. Break the glass and the filament gets plenty hot to ignite the gas). And it ought to be fairly easily scaled-up.

    Reminds me of a friend who supposedly filled a plastic bin-bag with acetylene and oxygen.

    The problem with FAE's is to get the mixture at an explosive concentration throughout. One alternative is to use a more forgiving (but difficult-to-obtain) fuel, such as ethylene oxide, and one advantage with creating Browns gas is that you get a stochiometric mixture straight away. (Even though hydrogen is good in that it has a very wide range of useful concentration.)

  5. Popup Says:

    Gah.. When will we get editable comments? Or at least a preview?

  6. TwoHedWlf Says:

    Depending on your exact definition of "Blow up" a sledge hammer, lpg tank, power strip, a couple timers and a light bulb could work well at least destroying the garage. Easy enough to rig up a way to drop the sledge on the tank valve, wait 10-15 seconds and then trigger a broken lightbulb to ignite it. Probably not so reliable and not something you can fit under your jacket.

  7. NickL Says:

    Supermarket? Probably not.

    Decent hardware store? Probably.

    I know for a fact that one can readily purchase Nitric Acid and Toluene at Ace Hardware stores, and I believe Lowe's Home Improvement Store.

    You still have to know how to refine and combined it, but this can be done with expedient lab equipment, or for the sane, a few hundred dollars of proper glassware.

    (Mind you, one has to have a permit to procure glassware in the state of Texas for this reason...)

    Glycerol is available at any Walmart. And all you have to do to refine it is boil the water off in an open pan on a cook top! (Refining Nitric Acid tends to be more problematic, and is best done via vacuum distillation. Which isn't to say it's *hard*, a few hundred USD spent on a Pyrex distillation rig coupled with an aspirator should work nicely.)

    N.B. I have never preformed any of these processes first hand. I am not a chemist. I do not, personally, own any glassware. The above post does NOT constitute intent to preform such actions. It is purely academic in nature and should be regarded as such. This is based solely on my understanding of chemistry and may be entirely inaccurate.

  8. Changes Says:

    Butane/LPG cartridges and cylinders, both of which are available at many supermarkets, are probably the best way to cause a nice boom.

    You'd need the following: 1) one LPG cartridge; 2) one camping tool using such a cartridge (say, a mini-stove); 3) as many larger cylinders as you can get.

    The Plan:

    1) insert cartridge in stove;
    2) place stove and cylinders in opposite corners of the garage;
    3) fire up the stove, then open all the valves on the cylinders to full as quickly as you can;
    4) haul ass.

    If all goes according to plan, enough gas will have flown out of the cylinders by the time it gets to the open flame that a nice boom should occur. If a nice boom doesn't occur because the gas isn't enough, a fire is practically certain. If hot enough, the fire would then eventually heat up the cylinders enough that the remaining gas inside them would increase in pressure enormously, and possibly cause a BLEVE.

    Supermarkets also often stock firecrackers, at least around here. They don't contain high explosives, of course, but there are shelves and shelves full of the things. Mix enough of them and the results are bound to be spectacular. Perhaps someone better versed in chemistry than me would know some household chemical you could add to the mix to make it go boom better.

    Ooh ooh, got another one! If the supermarket is a WalMart or similar, and stocks RC gear, grab all the lithium polymer cells you can get and make a pile of them. Take a few, short them and toss them back in the pile. Run. Ok, no spectacular KABOOM blast is likely to occur, but an escalating fire is practically certain. And if the place also stocks nitromethane fuel for RC engines, then you can make things really interesting...

    Perhaps a steam explosion would be enough to blast a garage. Get a pressure cooker, an electric stove and a welder to weld the safety valve shut. Fill with water, place on stove at maximum power, calmly walk away. For bonus points, fill with flammable liquid instead of water and use a gas stove instead of an electric one...

    Or, if the store is really large and sells household appliances, you could do like the Mythbusters did and disable the safety features of a large water boiler. That boom did actually level to the ground a small building.

    Note that I'm by no means a terrorist or a dangerous person by any stretch of the imagination (no, really, I'm a good guy. I actively try to stop my girlfriend from squashing small spiders :p ). This is just the product of a rational mind analyzing a problem.

  9. matkun Says:

    While all of these suggestions are great, they are all 1) Guesstimates 2) Unlikely to actually 'blow UP' a garage. It might create a fire/small explosion, but I don't think any of these would make a garage go boom enough to even knock some stuff into your neighbour's yard.

  10. Jens Says:

    Well I am a chemist.
    Most things suggested would make a mess that really annoys the neighbours, but that´s about it.
    That is simply because you need an awful lot of those substances to truly get an earth shattering kaboom. Most people think it´s possible because they heard of terrible accidents with those things involved.
    Well, yes but those accidents involved tons of the stuff.
    How would you get, say, a 10 cubic metre gas tank into an airplane?
    Besides, this accidents happen. To make it happen ON PURPOSE is a completely different pair of shoes and believe me, it is not easy. It is so difficult in fact, any mayor chemical company has an own research department that tries exactly that: to make stuff go boom on purpose so they can create safety guidelines.
    To make honest to jonny explosives, well it can not be done with stuff from the supermarket. You need industrial grade chemicals and you still need a lot of them. The most critical reagents for most recipes, red smoking nitrous acid and oleum for example are needed in an oversaturated state. This means, you simply can not get them to the needed concentration by destillation alone (And you will not be able to buy them, at least not in any civilized country, thanks to Aum Shinrikyo.)
    Heck, we are a mayor company and since 1995 we need special permits to buy and handle those reagents. We are bound by law to report where every single gram of the most critical substances went at a request by the authorities.

  11. stevetecza Says:

    3% H2O2 solution works fine for making AP, it just takes longer and requires more acid catalyst.

    35% H2O2 (pool store, hydroponics store) will finish the reaction in a few minutes, 3% might take you 24 hours, just because of the extra water diluting the reactants.

  12. Warg Says:

    Acetone makes explosive mixtures with air over a very wide range of fuel/air ratios. For a smallish garage-leveling (or at least garage-damaging) Boom, use a one-liter glass bottle of acetone and an emergency flare as the ignitor. I mean the sort of flare that's launched up into the air either from a flaregun or a pen-style launcher; they're sold as emergency equipment for use on boats, in most stores that sell fishing tackle etc. If you're using the small, pen-style flare launcher, the flare will fit inside the bottle mouth. Rig some sort of remote trigger device (a pin and string will do). The smallish blast of the flare lofting charge will do a halfway-decent job of bursting the bottle and spreading the acetone around the room, and the burning flare will then ignite the vapours.

    Now, I've only ever tried this with an electrically triggered blasting cap instead of a launcher to ignite the flare. The blasting cap obviously helps a great deal in atomizing the fuel, but then we used gasoline which is more difficult to get an explosive fuel/air mixture with. Using acetone, I'm pretty confident that you'd get a nice fireball with just an ordinary emergency flare as the bursting/igniting charge. If not, there's noisemaker flares sold that make a very loud bang; these ought to work but may be more difficult to find.

    I'm pretty sure you can find both flares and acetone in many supermarkets, at least in any decently sized mall where there's at least one sporting goods outlet and a hardware store.

  13. chickenface Says:

    this guy apparently used a sparkler to set off his bomb. He mightn't have been able to get everything he needed from a supermarket, but Bunnings? maybe.

    [That was an ANFO bomb, and the report that he used a sparkler as a fuse seems to be, presumably deliberately, leaving out what the sparkler was actually stuck into. ANFO is a low-sensitivity explosive; you can't set it off with a mere fuse. There isn't a "blasting caps" aisle in Bunnings, either :-). -Dan]

  14. rndmnmbr Says:

    I think if you took any given chemist with explosives experience and gave them the run of a hardware store and grocery store, and they might surprise you with what they could blow down.

    Jimmy the Creepy Kid Living Down The Street, well, that's another story altogether. About the only thing he's going to do is blow himself up.

  15. Stefans Says:

    I've wondered about the possibility of forcing petrol through a mister (like a carburettor) with a gas under pressure (Propane, for example). Seems like if you manage to get it right you could make a small scale fuel-air bomb. Get it wrong, of course, and you're in a burn unit and then prison. Anyone know if this is feasible? I really don't want to try it (Does the petrol station outside the supermarket count, anyway?).

  16. yasth Says:

    There is a massive difference between what one can blow up given no space requirements, and what one can blow up with apparatus that might be called discreet.

    Anyways, most of this discussion is silly. I mean for god sakes you can buy both black powder and gun powder by the kilo. Any decent sporting/gun store will sell this to you, and black powder can be made with relative ease using little more than what one might find at a campsite (and a lot of time).

    As impressive as a flour bomb might be... couple kilos of a properly packed and compressed powder will do wonders on your garage.

  17. Changes Says:

    Matkun, Jens: while I'll agree most of what I said is unlikely to cause serious booms, are you certain propane cylinders wouldn't blow up with enough force to do some serious damage?
    I've seen videos of such things going up, and always thought "man, am I glad this isn't happening in my home".

  18. Jens Says:

    Changes: It is possible, but not reliably so.
    Most times the darn thing just burns out, albeit with a very impressive flame. While this would certainly be a tad inconvenient given, that you will no longer have a home it is hardly what I call an explosion. Problem is, you have to mix it with air to go boom. If you manage to blow the thing up and THEN ignite the mix you have an explosion. If you don´t manage to mix it you have a fire.
    Again, for terrorist uses we need something small and conceillable. A Propane tank of adequate size is neither.
    We have to talk size here Your propane cylinder against, say 2 grams of TNT. Two grams fit in a teaspoon. Who would "win"?

  19. Changes Says:

    I never for a moment thought propane could win against TNT, but store clerks look at you funny if you ask for high explosives. :P

  20. reyalp Says:

    To assume terrorists need something small and concealable is movie plot thinking. Getting a vehicle within range of a lot of people isn't hard.

    Jens is correct, it's hard to get a propane to really go boom. The tanks are designed to vent (which makes a big flame, but not an explosion). Even if you release a whole bunch at once, propane has a narrow combustion range, so lighting it off is harder than you might think. Getting a BOOM rather than a FOOMP is harder, but a FOOMP in a confined space can be pretty damaging.

    That said, I'd bet if you dedicated yourself to making propane tanks go BOOM, you could eventually get a reliable system that would demolish a garage with a 5 gallon can. Perfecting that before someone noticed your efforts would be a different story.

    Other options:
    Hydrogen has a MUCH broader combustion range, and can easily be produced, either by electrolysis (slow and power intensive) or from commonly available household materials. Storing and transporting the shear quantity equivalent to a propane can would be present difficulties, but you may not need to. You can also get it in bottles, but not in hardware that stores I know of.

    Acetylene (which isn't supermarket, but can be found in hardware stores here) is also easier to make go boom. Welding tanks have various safety features, but producing a garage leveling boom wouldn't be much trouble. Unlike propane, it's just itching to take your face off.

    An alternate approach for things like propane is to add oxidizer, i.e. a bottle of pure O2 (again not supermarket, but easy enough to get.) If you bust open an 02 bottle and a propane can in close proximity, the whole "mix your propane with air" problem pretty much goes away... along with your garage. Of course, if you are buying an oxygen bottle, you might as well go with acetylene.

    Highly compressed oxygen (or even air) in the presence of various common substances results in an explosion hazard.

    Non combustion "explosions" of things like boilers or air tanks can produce garage leveling events if their safety devices are disabled.

    Overall, I'd say you can make plenty of stuff that could get the job done. Most of it won't come close to TNT pound for pound, but it doesn't need to.

  21. Warg Says:

    Of course, in most (all?) civilized countries, anyone growing up in the countryside sooner or later comes across an improperly stored stash of old blasting caps and frighteningly sweaty old dynamite. I know I did; we used to bring blasting caps to school and blow up the handlebars of people's bicycles. Stick the cap inside the hollow handle, and with luck it turns trombone shaped like Elmer Fudd's shotgun. Makes people really scratch their heads. That was a couple of decades ago, but I still come across old explosives now and then. Europe, and much of several other continents, is still littered with WWII and earlier explosives; just today I recieved a call from a man who found a fully functional "Mills' bomb" (brit handgrenade) while cleaning out his attic. His grandpa was a resistance member during the war, and simply left (or forgot) the grenade up there at war's end. A real terrorist wouldn't have much trouble scoring real military-grade high explosives, if he had the balls and the skills to search for old munitions dumps and scavenge explosive filler from rusty old arty shells etc. Which is precisely what they're doing in Iraq for making IED's, btw.

  22. Red October Says:

    I think that everyone has proved what I said in my first post... it's pretty easy to think of a dozen ways to get an explosion of non-trivial size. I can't believe I forgot about lighter gas when there are three cylinders in front of me as we speak (type?). The clincher is that it's another matter entirely to get a whacking great explosion of the kind that would interest a career madman, unless of course you pile it all into a truck in quantities that would make people at least think twice.

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