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.