On the Implausibility of the Explosives Plot

Really interesting analysis of the chemistry involved in the alleged UK terrorist plot:

Based on the claims in the media, it sounds like the idea was to mix H2O2 (hydrogen peroxide, but not the low test kind you get at the pharmacy), H2SO4 (sulfuric acid, of necessity very concentrated for it to work at all), and acetone (known to people worldwide as nail polish remover), to make acetone peroxides. You first have to mix the H2O2 and H2SO4 to get a powerful oxidizer, and then you use it on acetone to get the peroxides, which are indeed explosive.

A mix of H2O2 and H2SO4, commonly called “piranha bath”, is used in orgo labs around the world for cleaning the last traces out of organic material out of glassware when you need it *really* clean—thus, many people who work around organic labs are familiar with it. When you mix it, it heats like mad, which is a common thing when you mix concentrated sulfuric acid with anything. It is very easy to end up with a spattering mess. You don’t want to be around the stuff in general. Here, have a look at a typical warning list from a lab about the stuff:


Now you may protest “but terrorists who are willing to commit suicide aren’t going to be deterred by being injured while mixing their precursor chemicals!”—but of course, determination isn’t the issue here, getting the thing done well enough to make the plane go boom is the issue. There is also the small matter of explaining to the guy next to you what you’re doing, or doing it in a tiny airplane bathroom while the plane jitters about.

Now, they could of course mix up their oxidizer in advance, but then finding a container to keep the stuff in that isn’t going to melt is a bit of an issue. The stuff reacts violently with *everything*. You’re not going to keep piranha bath in a shampoo bottle—not unless the shampoo bottle was engineered by James Bond’s Q. Glass would be most appropriate, assuming that you could find a way to seal it that wouldn’t be eaten.

Read the whole thing.

EDITED TO ADD (8/16): More speculation.

EDITED TO ADD (8/17): Even more speculation.

Posted on August 16, 2006 at 7:32 AM91 Comments


Walkin August 16, 2006 8:02 AM

Too bad people in general don’t really care about what can actually be done. They’ve seen too many movies where a gun shot hole in the window can cause the plane to crash along with countless other impossible ways to crash a plane. So first you have to unconvince them that movies aren’t real before you can convince them that attacks like these really aren’t plausible.

Jim August 16, 2006 8:22 AM

Are you saying that they shouldn’t have been arrested because their plan probably wouldn’t have worked? Or just that we should still be able to bring our shampoo and coke on the plane?

TOMBOT August 16, 2006 8:24 AM

Quit blaming the hoi polloi. That’s a cheap cop-out.
Blame the people who have a vested interest in keeping their “demographic” or “electorate” in a panic state, even when it means lying through their teeth.

Josh Poulson August 16, 2006 8:31 AM

Richard Reid, the “shoe bomber”, supposedly had an operational TATP bomb he was attempting to detonate when he was subdued by his fellow passengers, so apparently these bozos have worked out these issues.

Note: the terrorists planned to combine the materials in the forward bathroom. Airplane bathrooms have this nice stainless steel sink and glass mirror that can be yanked off the wall…

Daniel Haran August 16, 2006 8:34 AM

@Jim: I think what he is saying is “go read this interesting article.”

The more we learn about this, the more it looks like a security fiasco. When people don’t have passports and can’t board planes yet, surveillance can continue. Arresting them prematurely might let conspirators off the hook and able to perpetrate an attack in the future.

Aaron Muderick August 16, 2006 8:36 AM

Although he didn’t use ATAP, Ramzi Yousef did smuggle a liquid explosive past security and successfully detonate it on Philippine Airlines Flight 434. He used liquid nitroglycerine. The explosion failed to down the plane because it was not placed close enough to the fuel tank.

My knowledge of chemistry is amateur, not professional, but I can come up with a number of scenarios where this scheme would world. Just because the specific details of a ‘leaked rumor’ are implausible doesn’t mean the actual effort would have failed.

Thomas August 16, 2006 8:37 AM

Wow… that’s it!

They didn’t want to mix explosives. They wanted to pour hydrogen peroxide and sulfuric acid into the planes toilet hoping it will heat up so much that a hole melts into the tank and the planes skin…

Isn’t that a movie plot scenario? Or has the contest already ended? 😉

Fotios August 16, 2006 8:48 AM

Maybe we shouldn’t watch out for the people with the bottles, maybe it should be the ones with “a full face shield, heavy duty rubber gloves …, as well as an acid apron” and “a full size bunny suit”

bg August 16, 2006 9:41 AM

Removing water bottles and cosmetics creams is nice security theater. There’s a reason why prisons have rectal checks.

Matthew X. Economou August 16, 2006 9:50 AM

The linked article is one of the best recent examples of typical “hacker” thinking that I’ve seen. I wish that educators would teach this kind of critical and detailed analysis in school. Many of the airport security measures have trivial exploits, and (sadly) most of the measures just move the location of the threat off the plane (where a bunch of people die up in the air) and into the airport lounge (a target-rich environment with even more potential to disrupt a society or local economy and by definition with less security). Frankly, I worry a whole hell of a lot more when I’m standing in line at the Washington Monument or the airport security line, or when the nightly freight train comes rumbling through, containing tanker cars full of God knows what kind of nasty chemical, than when I’m actually sitting in my cramped economy seat 30,000 feet and several hundred miles away from dry land.

1234567890 August 16, 2006 10:25 AM

Dunno if it was a political act, or a plain misdirection from other problems. This is too easy to put afront everytime when you have no prove.

The liquid explosive idea shows that they evolve around security measures, it it shows even more that they are capable of outsmarting the so-called security experts. This disturbs me the most.

The Anonymouse. August 16, 2006 10:32 AM

a glass container is easy to seal with glass. pour the mixture into a bottle with a small neck, heat the neck until molten, and clamp it shut. Do all of that before you head to the airport.

later on the plane, break off the thin neck and the bottle is opened.

if you are able to place a small bottle of this pirhana bath into a larger bottle of acetone, THEN break the inner bottle, this suddenly becomes quite easy to do despite airline levels of turbulence or prying eyes.

it is possible to do this, and its not entirely implausible. While I don’t think that airport security will catch the craftiest terrorists, it will probably stop the street-corner nutjobs with a death wish easy enough. Unless he’s a 12 year old without a passport or ticket.

Mr Pond August 16, 2006 10:55 AM

Whilst this may seem a rather flippant comment to make it is nevertheless relevant:

I wish I could make money from baseless, circumstancial speculation.

Not having a go at Bruce, at least his articles are in general well thought out, but most of the drivel on the net regarding this incident (or lack of incident, let’s not forget that) can easily be ignored.

J.D. Abolins August 16, 2006 11:01 AM

Re: the instability of TATP, there’s a reason it’s nicknamed “Mother of Satan”.

Meanwhile, a recent NJ news article churns up the worries by claiming, “Made from items found in supermarkets, the colorless, odorless solution is highly unstable.”


Echos of the McGyver TV-series with the kitchen consumer-grade substance dangers themes. At least, the air security folks aren’t asked passengers, “have you or anybody you know been to a supermarket…?”

Jimi August 16, 2006 11:04 AM

I thought horseshoes and hand grenades after reading this and the comments. The news had a story about some terrorist computer expert. I haven’t seen anything about who they have as a chemical experts. I remember Chemical Ali got a bunch of press. He was the King of Spades in the Iraq most wanted deck of cards. The ebayers joined in the fun and a cottage industry started selling Iraqi most wanted playing cards, with high quality artwork compliments of Central Command. People had a lot of fun with it and made some money. The terrorists aren’t playing with a full deck of cards and now they are playing with chemicals. It sounds like the same type of people who build meth labs here in the United States. You are going to get caught, injured or possibly blown up or all three messing around with chemicals. You aren’t going to be a big success with some makeshift basement lab planning world destruction or an illegal drug empire on a global scale.

Perry E. Metzger August 16, 2006 11:05 AM

As the author of the linked article, let me say how disappointing it is that people are criticizing it for things that it did not say.

I did not say that TATP isn’t a real explosive and that it hasn’t been used by real terrorists. I said you can’t easily make it in ain airplane bathroom.

I did not say that there are no real two part explosives, both liquid and solid — but the claim in the media was very specific: that the plot was to make acetone peroxides in the air, and my claim is that this very specific method is implausible.

To the person with the elaborate ideas on how to make TATP on board in spite of the various problems associated with it — congratulations on ingenuity, but you’ve neglected the real problem, which is that you need to mix the materials very slowly and gently or they’ll blow up long before you have enough explosives made to bring down the plane, and that you need to mix the materials under cooling — even ordinary ice isn’t really optimal though terrorists have done that in home bathrooms anyway, sometimes blowing themselves up in the process. Given that airport security is incapable of detecting pre-made acetone peroxides in the first place, why risk your reward of 77 virgins by trying to go for the “movie plot” when you can just take the stuff on pre-made? It isn’t like the precursors are invisible and the manufactured material is easily detected — in fact, the precursors are far easier to detect than the product, since almost everyone knows what nail polish remover smells like and the other chemicals are irritants.

In any case, given that the overall method we’re using to secure airliners is doomed — please read section that follows carefully and understand I was not joking although I inserted some levity here and there — what is the point in the deck-chair shuffling? Stop any given “movie plot” and ten thousand others wriggle out. You can never win the game that way. The sad thing is, people can’t break themselves from thinking this way even though far more effective measures are well understood. If your strategy isn’t working, the solution is NOT to try to keep repeating your mistakes more enthusiastically.

DueProcess August 16, 2006 11:08 AM

BTW, what happened to the suspected terrorists? It’s been a week; shouldn’t they have seen a judge, or at least an attorney by now?

All the time I was expecting dramatic footage from a court room where a judge read the charges against them, and the captives declaring their innocence, and a judge braving the microphones to tell us that his clients have been innocently caught in the cross fire.

Or have they just been shipped to Guantanamo?

Mike Z August 16, 2006 11:12 AM

Is this post supposed to be a tip to potential terrorists, or what?

Consider the Martha Stewart pattern – everyone can figure out how to make pea soup given enough time. Martha’s shows and books are so popular because she shows people how to make pea soup in an easy, clear, efficient, and fun way, without using hard-to-find obscure chef tools. Because of her, more people make pea soup because they see how to do it.

Many top chemists will tell you that mixing hyrdogen peroxide with shredded business cards (which have >50% green ink) will make a huge blast when ignited. Sure, “security through obscurity” has been widely discredited. So has “security by giving them bombs”.

Adam August 16, 2006 11:15 AM

So I wrote something very similar in my blog. I’m going to repost it here:

Well, gosh, look. It happened again.

Folks… if $(group) wanted to blow up planes, planes would be blowing up. It’s just not that hard to do, really, since security still has gaping holes, I guess it’s spectacular, and planes are expensive. If $(group) wanted to kill people, people would be dying. Think about how few it would take before the country really panicked and we did something stupid. What, 100 maybe, definately 1000? The WTC was 3600 or so, what would we do if 10000 died?

But if $(group) wanted to cost the west a few $ billions, then they don’t have to actually blow up planes or kill people. They don’t even have to have a plot that would succeed. They do need to get caught, and it has to look like success was a possibility. Holy crap, what an advantage that is: they don’t need good people, they don’t have to be meticulous, and they don’t need a lot of inve$stment – all they have to have is a steady enough stream of cannon fodder to cause an attempt to be thwarted every so often. If one succeeds, so much the better, but $(group) wins in either case, as long as the percentage of our resources that is sapped is greater than the percentage of theirs expended.

I think that if I were to take the position of the opponent in this manner I’d concentrate on putting explosives, bombs, and other whatnot into the luggage of unsuspecting others with the intent that they get caught at security. I think the $ and morale damage there would be the best payoff, and I don’t have to implant as many people, nor do I lose those I implant as often. In deciding on this as a strategy, I ingore the star-appeal of spectacular attack attempts in terms of recruitment and fundraising and the generation of independant copycats that cost nothing. Maybe a modified version of this is already what is occuring, with the implanted ringleaders already here generating attack attempts by recruitment on this side with the ringleader walking away each time to start afresh.

How much better to attack the source of the problem rather than the symptoms. Or avoid it. Were it not for oil, there would be no need to stabilize the middle east – we’d just need to make sure that there was enough internal conflict that they didn’t stop fighting each other and then stay far away. We’d still worry about nuclear capable Russia, India, and Pakistan, but that’s one less theater to concentrate on. Still, were it not for oil, we could almost just walk away completely.

David August 16, 2006 11:26 AM

Yes, the terrorists were skilled enough to make this explosive mixture, but weren’t smart enough to carry under their clothes where the metal detectors wouldn’t see it, so that’s why we can’t carry water or books on planes anymore!

Joe Buck August 16, 2006 11:33 AM

I could say “amen” to the Craig Murray article as well, but I think I’ll point you to a different link, which is more fun:


It’s inspired by a “Chuck Norris facts” site, evidently, done by a bloke who also has a T-shirt for sale that says “Knuth is my homeboy”.

Jimi August 16, 2006 12:01 PM

The terror plotters are down to the bottom of the barrel field terrorists. The idiots who couldn’t get a job selling coke, h or pot are trying to make their own meth at home out of starting fluid and cold pills. These British plotter rejects seem to be the same type. Rejected by the top management of terrorism, they are told to go away. Go play in the traffic with chemicals. With nothing better to do, they are planning their own explosives jihad in the basements of England. In one day everybody with a bottle of water is a suspect at airports worldwide, costing the world millions of dollars and hours. The odds of a crash due to mechanical failure aren’t that great. We have a lot of broken people out there trying to break our stuff. The jets are more dependable than we are. People aren’t afraid to fly. People aren’t afraid of much these days. Terrorism has not upped the ante as much as it has increased our tolerance. People are going to keep flying and put the fear out of their minds along with hairspray. There are people getting on jets right now going about their business, without bottled water. They keep saying we aren’t safe we are safer, whatever that means. Good luck staying safe or safer.

theophylact August 16, 2006 12:05 PM

You couldn’t possibly make triacetone triperoxide using “piranha bath”, because the conditions would boil away the acetone in an instant, even before the acetone was chewed up to carbon dioxide and water. Only catalytic amounts of acid are required.

More to the point is that TATP is volatile; it tends to sublime away in solid form. You can make it up in solution, but it’s probably a far less efficient explosive when diluted enough to make it stable enough to carry around.

Crypto August 16, 2006 12:08 PM

Mr. Pond said:
“Not having a go at Bruce, at least his articles are in general well thought out, but most of the drivel on the net regarding this incident (or lack of incident, let’s not forget that) can easily be ignored.”

Hey, you better watch out! Having a go at Bruce is risky! Because…
When Bruce Schneier does modulo arithmetic, there are no remainders. Ever.
Bruce Schneier once broke AES using nothing but six feet of rusty barbed wire, a toothpick, and the front axle from a 1962 Ford Falcon.
When Bruce Schneier uses double ROT13 encryption, the ciphertext is totally unbreakable.
SSL is invulnerable to man-in-the-middle attacks. Unless that man is Bruce Schneier.

Remember: As initialization vectors, ‘Bruce Schneier’ and ‘Chuck Norris’ are interchangeable.

Brian August 16, 2006 12:10 PM

Perry, I think you’re missing something pretty fundamental. Heck, read the page you yourself linked to in the quoted article:


From that page:

There are many things which will cause the reaction to accelerate out of control. “Out of control” can mean anything from the piranha foaming out of its bin and on the deck, to an explosion with a huge shock wave including glove and acid-gown shredding glass sharps. Piranhas burn organic compounds. If you provide sufficient fuel for them (i.e. photoresist, IPA), they will generate enormous quantities of heat and gas.”

You correctly point out that it’s unlikely terrorists could use this reaction on a plane in a fashion that would yield sufficient quantities of organic peroxide to bring down the plane.

But so what? The reaction is itself capable of producing an explosion. You don’t need to generate any TATP at all, you simply need to mix sufficient reactants together fast enough to get a runaway, at which point the reaction will rapidly generate “enormous quantities of heat and gas” with a “huge shock wave.”

We call that a detonation. The fact that the yield of TATP might be negligible doesn’t keep the plane in the air.

Anonymous August 16, 2006 12:14 PM

If you want Bruce Schneier facts, he has books on the market. Quit trying to send people to your dumb websites. These are the people behind the last dotcom crash. Nobody cares about your dumb websites with facts. What you don’t know could fill a book.

Brian August 16, 2006 12:24 PM

It’s interesting to look at which media is reporting the acetone peroxide bomb information and which is not. I can find references on american web sites saying that the recent plot involved acetone peroxide, but none of those references cite primary sources. It seems to be pure speculation.

The UK web sites do mention acetone peroxide, but not in the context of the recent plot. They mention acetone peroxide as the 7/7 explosive.

I think the american news organizations are making a great deal of noise with very little actual information. It’s incredibly shoddy reporting. Even news organizations I normally trust are publishing this information without any sources. The scary thing is I suspect that DHS and TSA feel compelled to respond to these kinds of news reports.

Christopher August 16, 2006 12:26 PM

Today they ban liquid, yet, they still provide water on the plane. Calcium carbide CaC2 is almost free to get everywhere in europe, it has no smell, no dog can smell it, combined with water you will ge Acetylene gas CaC2(s) + 2 H2O(l) -> Ca(OH)2(s) + C2H2(g). If you brought Calcium carbide on the plane. you would simply need to visit the rest room and add it to the water. Instant Acetylene gas. A match or a spark from a tampered smoke detector or light would be enough to ignite the gas. The material would be stable until mixed. Would it be enough to take down a plane? Maybe not, but it would cause a fire onboard and consume oxygen and produce smoke. The idea would be panic. A fire on a plane is just as dangerous.

Anonymous August 16, 2006 12:35 PM

Attacking a plane doesn’t require explosives. If someone is willing to die, then mixing in a couple of ounces of sodium cyanide with a bottle of hydrochloric acid should produce enough HCN gas for the whole plane. The AC system should be pretty helpfull in distributing it around the cabin.

109 August 16, 2006 12:38 PM

There is no need to mix the liquids on the plane. Aceton peroxide, the result of the reaction between H2O2 and acetone, does not contain nitro groups and therefore undetectable by conventional means, so they could as well prepare it beforehands.

scott August 16, 2006 12:50 PM

As someone who has made and used piranha solution, and back in my misspent youth made TATP and HMDT, I must comment. BTW, it is more properly ‘solution’ and not ‘bath’; bath is when you are soaking objects in it, while a common use is to clean glass filters by sucking piranha solution through them.

A few minutes more searching the Internet, or reading underground books from the early 1970s, would have given a bit more information on both piranha solution and the explosives.

Piranha is made by mixing about 3 parts of concentrated sulfuric acid (98%) with one part of 35% hydrogen peroxide. If you add acetone to it you will get an explosion, this has happened accidently, to people using it for cleaning labware, enough times that it’s use is often banned.

Now, if this strongly oxidising solution explodes on adding acetone to it, how can it be used with acetone to make TATP?

The answer is that much less acid is used when making TATP or HMDT. The acid serves as a catalyst, only about 1 part to every 10 of peroxide. Generally the acetone and peroxide are mixed first, then the acid is added; it is not likely that the bombers were planning to be carrying around an acid + hydrogen peroxide mixture.

With HMDT you don’t even need a strong mineral acid, citric acid will do. While you can’t get away with using lemon juice, you’re not dealing with an extremely corrosive material.

It does take low temperatures such as ice cooling to make either TATP or HMDT, if you want to isolate them. However a suicide bomber might not care about fully isolated them, just about getting a mix that could be detonated. In that case it doesn’t matter if it explodes while you’re working with it, so long as it brings down the airplane.

A real problem with using either explosive is that reaction to make them is slow, it takes the better part of a day. This suggests that the explosives were to have been made first and brought aboard disguised in some fashion; mixed with a strong solution of ammonium nitrate and chilled below 0 C might be one way.

RSaunders August 16, 2006 12:50 PM

Actually the Wikibooks link is much more accurate.


You’d want to mix the H2O2 and acetone before slowly dripping in the H2SO4. As folks have said, you could do that before you get on the plane. The whole dry-ice technique presumes you really want the mostly unstable triacetone triperoxide rather than the super unstable dicycloacetone peroxide. If your plan is to pour it on the carpet to filter our the crystals, say your prayer, and stomp on it to blow up the plane – you might not be so picky.

Mord August 16, 2006 1:56 PM

I’m surprised they haven’t started strip searching people. I hate to be so petty as to say I won’t fly because I can’t have a beverage, but… I don’t plan on flying because they are treating me like a criminal at the gate.

Anonymous August 16, 2006 2:00 PM

Speaking of which, now that laptops have to be checked luggage, waht about bringing a plane down with a bunch of Dell Laptop batteries.

ColoRambler August 16, 2006 2:56 PM

Don’t forget alkali metals. They react immediately with water to produce hydrogen gas, as well as enough heat to ignite the gas. If you’ve been in a chemistry class you may have seen an instructor drop a small chip of sodium into a big beaker of water. The sodium scoots around the top of the water, fizzing hydrogen as it goes. The instructor uses a small chip, about the size of a BB, and a large beaker (2 liters or so). If you use a bigger chunk, say 25-50 grams or so, you can get a very large fire or even an explosion:


I’m sure anyone here can think of multiple ways to cause havoc with a few grams of sodium and the existing water on a plane.

averros August 16, 2006 3:17 PM

Like many chemistry geek schoolboys in less regulated parts of the world, I experimented with explosives. That included synthesizing TATP.

What the analysis you referred missed is that it is not very useful in solution, you need to wait while it precipitates.

That usually takes a day or two if you use reactants dilute enough to avoid high likelihood of blowing the work in progress, before an effective quantity of TATP is made.

Then you have to dry it, carefully.

Fearmongering, plain and simple.

Kripto August 16, 2006 3:22 PM

Oddly enough, airports are requiring people to dump out their liquids. I wonder what would happen if someone had 2 bottles dumped out at that same time, h2o2 and ns2so4…

Jimi August 16, 2006 4:28 PM

The whole plot was nearly impossible to pull off. They take a plan that has been tried before for openers. I read about this sort of thing a couple of years ago. Then they make it much bigger. They obviously talked to people they weren’t sure about, giving details. They might as well posted the entire plan on website with directions to their houses.

JM August 16, 2006 4:30 PM

So what? All this proves, if it proves anything, is that (some) news outlets got a specific aspect of the incident wrong. It proves nothing about whether or not its a good tactic to forbid liquids and gels on an airplane. What you did was the extremely long and masturbatory equivalent of noticing an article about the space shuttle in a newspaper that mentions that the shuttle is fueled by gasoline, and then pointing out that that’s improbable.

In other words, you ‘proved’ the media may have gotten the (very specific and mostly unsourced) details wrong. Big deal, happens all the time. Next.

Jimi August 16, 2006 4:38 PM

Now you have a million and one people online offering tips and advice on how to maybe blow a commercial jet out of the sky. The world is crazy!

rob August 16, 2006 4:55 PM

While all of this discussion on the feasibility of the mechanism is very interesting and may apply a correction factor to the current hysteria, please remember that many people in the government (I believe up to and including the US president) were under extreme pressure to state exactly when and whether they knew about intelligence reports on plans to take-over planes prior to 9/11. Just like Pavlov’s dogs, if you cause politicians lots of stress whenever hindsight shows that an implausible plot was in fact plausible, they will tend to react to any plot NO MATTER HOW IMPLAUSIBLE next time.

Also, (sorry I cannot recall the reference), I remember reading a discussion of a pre-election debate in which one of the candidates was hammered in the public opinion poll for using a reasoned approach to fighting terrorism. The candidate fell into line with the rabid “kill ’em all” speeches in the next debate.

Jimi August 16, 2006 5:01 PM

JM makes a good point. The media was wrong but the chick on the news at noon, 6 and 11 looked good telling the story. Our airport was a media circus and I didn’t hear one reporter ask a serious question in a week of coverage. It was all wide angle video work (nicely done I might add) pics of huge trash bins full of mixed, but otherwise recycleable stuff. In our market, the reporters don’t even talk to the cabbies anymore. We’re back to the deer crashing through windows, junkie robberies and old house fire news cycle again. There was just an arrest in the JonBenet Ramsey murder. It’s on the news now.

Roger August 16, 2006 9:08 PM

Sorry: this is WRONG, WRONG, WRONG.

I don’t know if the plot really involved manufacture of acetone peroxide during the flight–I have heard that report, but have no idea how authoritative it is, and there are many liquid binary explosives!

However, meaning no disrespect to Mr. Metzger (who makes no claim to be a chemist), his discussion about acetone peroxide synthesis is largey incorrect. In particular, contrary to his essay the synthesis does NOT involve preliminary manufacture of “piranha bath” (proper name persulphuric acid, a.k.a. Caro’s acid). In fact the sulphuric acid is only a catalyst added in much smaller amounts than the main ingredients, and after they have been mixed. It remains a matter of debate if persulphuric acid forms as an intermediate in this process (only to be instantly consumed), but it likely is not as the synthesis can also be completed with other acids.

The production of acetone peroxide by the conventional route is actually a fairly quiet reaction with no significant fume, unless you stuff up and allow it to overheat. It does require cooling, but does not need to be ice cold and a flow of cold water (available in the toilet) is probably sufficient. I don’t think it would be at all difficult in an aircraft lavatory–unless you struck turbulence, in which case it would get ugly!

The most reasonable objection to in-flight production is that the commonly described recipes involve leaving it to settle for 24 hours; however nearly all of this time is for precipitation which can be accelerated in various ways, so it may well be possible to get it down to the 7 hours of a transatlantic flight.

Pseudonymous Skeptic August 16, 2006 10:04 PM


I’m only speaking with a high school chemistry background here, but wouldn’t diluting the solution lessen the amount of precipitate formed?

Second, can any of those methods for accelerating precipitation be done with the things that you can reasonably carry into an airliner bathroom?

Finally, a picture of an airliner’s bathroom for reference. http://commons.wikimedia.org/wiki/Image:B747_toilet.jpg

Terry Karney August 16, 2006 11:27 PM

Anitmedia: The point isn’t that TATP is a joke (though it’s less useful than most think. The point about explosives is that they are unstable. The better of them are more controllably unstable than the lesser. TATP is one of the middling ones [more stable than nitrogen tri-iodide, less so than nitroglycerin, and prone to becoming less stable as it ages/gets warm, but I digress).

The point is that the “security measures” being implemented are not reasonable reactions to a realistic plot (as described) as such they are security theater, and (arguably) make people less safe by focusing the limited resources of those doing the screening on things which are almost impossible.

Terry Karney August 16, 2006 11:43 PM

I also think the use of the number “thousands” is a tad hyperbolic.

Here is the tally for the twenty years 1978-1998

1978 — 12
1979 — 14
1980 — 10
1981 — 5
1982 — 2
1983 — 6
1984 — 7
1985 — 14
1986 — 7
1987 — 5
1988 — 14
1989 — 32
1990 — 23
1991 — 26
1992 — 39
1993 — 64 (38 before Oslo; 26 after Oslo)
1994 — 73
1995 — 52
1996 — 92
1997 — 29
1998 — 7

That tallies up to 539.

(figures from the <a href =Israeli Embassy

The figure the Embassy gives from Sept 2000 is 1,103 (discounting the 18 they said were killed abroad).

So the dead do total more than one thousand, even the greater part of 2,000, but not thousands, and not the multiple thousands implied in the use you made.

What percentage of those were the victims of bombs using TATP?

And how many of those were killed by guys who whipped it up on the spot?

Is it used as a weapon? Yes, because, relative to things like tri-nitrotoluene, it’s easy to make, and much less likely to kill those who manufacture it (the Nobel family had explosions for as long as they made dynamite, and they were experts. The DuPonts had the tried and true methods of gunpowder manufacture go up in smoke; and they were experts; so those who decide to make things for themselves are, perforce, going to go for the more stable, in manufacture methods. Esp. those which don’t require the acquisition of hard to get/handle chemicals).

But it’s not something one can just slap together in the loo, which is what people here are saying.

antimedia August 17, 2006 12:10 AM

Who says they were going to “slap it together in the loo”? The news media? Like they’re a dependable source for the facts!

TATP is the preferred explosive of the Palestinians because it’s cheap and easily obtainable. What percentage of fatalities have been caused by it? I doubt anyone keeps those statistics. I don’t think anyone in the public knows enough about the facts of the plot to make any judgements at all about what the plan was, so all the pooh-poohing of the threat it represented is nothing more than vacuous speculation.

bah August 17, 2006 12:14 AM

Just go to the rear door, distract any lurking stewardesses, and crank the big red handle. See ya! suicide successful, plane will tear up just as well as any of the chemical solutions proposed above.

So why aren’t all the scary terrists doing this?

Because we are lied to.

Number one result from this escapade, is 90% of the public are scared of terrists, and the remaining 10% of us who know it’s hogwash can be identified.

Now they have a list, of wants and want-nots.

Let’s see what the next step is.

bah August 17, 2006 12:15 AM

btw I mean, “Because we are lied to.” == there are no scary terrists. Get over it.

The fucking politicians are scarier than the terrists. How scary is a politician?

WAKE UP. Do something interesting tomorrow!

bah August 17, 2006 12:27 AM

@rob: “Just like Pavlov’s dogs, if you cause politicians lots of stress whenever hindsight shows that an implausible plot was in fact plausible, they will tend to react to any plot NO MATTER HOW IMPLAUSIBLE next time.”

If you think that is the kind of behaviour we should expect from these “leaders” why then put them into positions of priviledge? If I wanted Pavlov’s dog, I would have voted for Pavlov’s dog.

Deathwind August 17, 2006 5:08 AM

Problem these days is that terrorists win both ways :

if their plot succeeds, they win blowing up some people,

if their plot fails, the security measures introduced reduce our freedom, make air travel a nuisance and everybody is more afraid thanks to media frenzy and overreacting. In short, even if they don’t succeed, we become more terrorized.

And thus they win as terrorism is all about spreading fear and terror not really killing people.

We have to try as much as possible to stop them from succeeding but we must try not to let them win even when they don’t succeed.

T August 17, 2006 5:44 AM

Bah said:

“Just go to the rear door, distract any lurking stewardesses, and crank the big red handle. See ya! suicide successful, plane will tear up just as well as any of the chemical solutions proposed above.”

As I understand it, this doesn’t work. It’s one of the reasons I get annoyed with the stupid news stories about “brave” passengers “saving their lives” by confronting the madman trying to open their cabin door.

Plane doors are held in place by internal presure, and need to move inwards before they can be opened. This means that disengaging the locking mechanism on the door still leaves you trying to pull a door inwards against the pressure inside the hull. Probably not practical.


Benj August 17, 2006 5:56 AM

And if you “mix” After the last check and before the boarding gate:
– glass bottle from lemonade at the local restaurant
– whiskey or other fairly high alchohol from the bar in the area (there is one at Logan Airport – but well see my next post on this)
– high concentrate cleaner from the cleaning cart going around from area to area and in the bathrooms
– rags, cloth, hankerchief or even toilet tissue
– a “light” from any of the smokers in the smoking area
What have you? Well if you have not figured this out, and the threat posed here….
The terrorists point is to cause terror, confusion and fear. Keep that in mind!

benj August 17, 2006 5:59 AM

And a real threat (which I was clue-ed in on by a really nice Mass State trooper).
The top floor of the General parking garage at Logan Airport – Boston offers:
– a CLEAR view of any plane landing and taking off (even to the point of identifying numbers on the side)
– lots of privacy – no body is up there even on a busy Sunday afternoon.
– no security to get access (just take a ticket from the robot at the bottom).
Again the threat should be really clear. And again the terrorists point is to cause terror, fear, and confusion.

nbk2000 August 17, 2006 7:14 AM

After DB Cooper lowered the rear exit ramp of a plane and parachuted out with thousands of dollars in ransom, the airlines installed interlocks to make it impossible for a plane door to be opened in mid-flight.

Terry Karney August 17, 2006 11:38 AM

Antimedia: The simple fact is that you are hyping TATP as being a huge scary thing, and while it’s dangerous, it’s not that scary.

Terrorists are scary, sort of. But you alleged (you, personally, right here) that not only had terrorists killed thousands of Israelis in the past 20 years or so, but that they had killed that many with a specific explosive.

Putting aside formal debate, where you are responsible for supporting all of your position, we’ll ignore the TATP issue, and look at the raw numbers.

In thirty years “terrorists” have killed about 1,500 people. Which gives the lie to the claim of thousands; which as I said implies more than just two multiples of 1,000.

Most people will look at that claim, and because of the “nasty media” you are abusing (who have to go on what Scotland Yard and 10 Downing Street tell them, so they have something of a pass for the claims. Those of us questioning those claims; and the “security” measures stemming from them are only being reasonable. Like them we have to work with what we’ve got), who have been flogging the idea that we are all in danger, all the time, from “terrorists.”

It ain’t so.

I am at greater risk of death from automobile accident, slipping and falling in the tub, being shot by a neighbor over a minor dispute and any number of things I deal with every day.

TATP, RDX, PENT, and a lot of other explosives are available. Some moreso than others. My real risk of someone killing me with them is probably higher than yours (because people pay other people to try and kill me… in addition I get sent to places like Iraq to collect human intelligence… I’m in the US Army), and I’m not worried about people blowing up planes because, in the grand scheme of things it’s not a high enough risk to panic over.

Why? Because as said the fragility of airplanes is great. Searching for trivial means of hijacking, or destroying them, is good. It makes it non-trivial to do so, which I think is a good thing.

But barring 100 percent strip searches, x-rays and cavity checks, stuff will be imported to airplanes, now and again.

Seeing boogey-men under every bed, and making those who travel miserable, because maybe someone might do something imlausible, is asinine.

And, as I said, it makes us less safe, which is stupid, because we will pay for that, and then there will be more over-reaction.

Brian August 17, 2006 3:08 PM

Articles like the one The Register just put up make me twitch. The media has gotten this story badly, badly wrong. First they claim the fabled binary liquid explosive was TATP, despite abundant arguments from chemists that TATP is not suitable for the task. Next, other folks debunk the TATP claim… but then leap to the conclusion that because TATP is infeasible, no binary explosive is feasible.

I’m going to quit reading the news for a bit. If I was interested in the kind of speculation that merits the front page these days, I’d read Tom Clancy novels.

Hal August 17, 2006 4:26 PM

Here’s another opinion suggesting that peroxide based explosives similar to TATP would indeed be feasiable. It’s from John Carmack, founder of Armadillo Aerospace:


“I can’t say for sure about acetone peroxides, but I can say for sure about some other organic peroxide mixtures. When we started out working with high concentration peroxide as a rocket fuel, we conducted a number of tests to determine how dangerous it really was, because most accounts that you hear aren’t from first hand experience, but instead are a collection of exaggerations of rumors from uncontrolled circumstances.

“One of the tests we did involved detonation of 98% peroxide / methanol mixtures. There is no reaction at all to the mixing, and it most certainly is a powerful high explosive. We detonated it with a blasting cap, but we have some reports from the 50’s that graph the sensitivity of a few different organic peroxide mixtures that show the experimentally derived breaks between can’t-be-detonated, detonated-with-blasting-cap, detonated-with-impact, and detonated-with-spark. Peroxide-acetone was reported as touchier than any of the other mixtures, but you could certainly pour the two chemicals together with the expectation of mixing them before blowing yourself up. Adding sulfuric acid would be pointless.

“We made dozens of rocket flights and hundreds of engine tests with a mixed-monopropellant consisting of 50% concentration peroxide and methanol, which many people thought was suicide based on misinformed lore. That particular mixture was just past the can’t-detonate-even-with-a-blasting-cap line.”

antimedia August 17, 2006 4:57 PM

Geez, Terry, (thank you for your service, BTW) I’m not hyping anything. I’m simply saying that saying there’s nothing there based on nothing more than news reports, which are notoriously incorrect is foolhardy.

I think there’s a great deal more danger from insisting that your government is made up of lying, incompetent fools than there is from terrorists. If enough people believed that, we’d have anarchy, and anarchy would kill more people than terrorists ever will.

There’s a great many things we do, in the security field, that make no sense at all but are designed as “feel-good” measures. But to insist that a plot wasn’t a plot, which necessarily requires that the government be lying, when you simply don’t know the facts, is foolish.

I also dislike the statistical minimizing that goes on (only x number died in y number of years, therefore the threat isn’t real.) I think it’s an insult to those who have died.

Here’s an idea. Why don’t we just remove all security from airports and put up big signs – “You are ten times more likely to die from cancer than you are from boarding a plane.”

Then we can celebrate our statistical successes over the bodies of the small minority that didn’t make it but proved our math and enjoy flying without being inconvenienced.

mc August 17, 2006 5:00 PM

I can’t comment on the plausibility of the scheme; I was reading comic books in high school chem class.

I can say that I’ve gone through 4 US airports in the past week. 3 of them had regular announcements saying “The Homeland Security Terror Alert Level is Orange, ” and then the same advice about looking out for unattended luggage as they’ve always had. What exactly is the point of announcements like that, except to cause anxiety and fear?

Also, the Atlanta airport set up a 100% screening station at the gate, where 5 TSA folks went completely through every pocket of every carry-on bag. The passengers had already been through the normal security checkpoint, and this was for a 1-hour flight. Needless to say, the plane was late departing. But hey, at least no one had any toothpaste when they were done, so that’s something.

DougC August 17, 2006 6:12 PM

I am reasonably expert at explosives and have made all the mentioned ones, as well as some others (yes, the BATF knows me, and we’re friends). If I were DHS, I’d be in the fetal position with my thumb in my mouth right about now. Maybe the newspaper scheme wouldn’t work well, but it could work.
Most of the debunking is done on the assumption that the lab worker intends to live through it. This isn’t the case here.
Heck, a couple of quarts of plain gasoline atomized and then lit would do the job of overpressurizing the cabin enough to burst it, acetone would work even better. Those who think you couldn’t smuggle a nitrate explosive aren’t aware that most airports do not have a nitrate detector or GC, just an x-ray machine, and look for density of common explosives. There are so many possibilites this job is basically impossible, and in deference to my friends at DHS I won’t mention some that haven’t come up yet. Those who mentioned alkali metals should remember the batteries in laptops and cel phones. Take out the safety circuit, short it, and you have a small hand grenade!

bah August 17, 2006 7:48 PM

OK, sorry about the plane door thingo .. still seems more likely to succeed than the supposed bomb plot.

My question is this: Does the movie plot scenario prize go to the UK Home Office now?

Adrian August 17, 2006 7:54 PM

“Now they’ve evacuated a terminal because explosives were ‘found’ in a water bottle.”

They found residue, not actual explosives.

antimedia August 17, 2006 8:15 PM

mc asks, “What exactly is the point of announcements like that, except to cause anxiety and fear?”

I wrote a step by step procedure (1 side of an 8 & 1/2 x 11 page) for our computer users to take care of a problem. (I even took the time to correctly spell and capitalize each stop of the process based on the screens the user would be seeing.)

Do you know many can follow the instructions? I have actually had users call me up and say, “I can’t get past step 10.” When I ask, did you try step 11?, they say No.

Not everyone is as attentive or retentive as you are.

Terry Karney August 17, 2006 8:50 PM

Antimedia: Which strawman do you expect me to defend?

I never said do away with all security. I, in fact, said security is needful.

I said wasting time on foolish security is counter-productive.

Roger August 17, 2006 11:16 PM

@Pseudonymous Skeptic:

but wouldn’t diluting the solution lessen the amount of precipitate formed?

Hmm? Who was diluting anything? Anyway, yes it would–but the effect would only be significant if the precipitate was appreciably soluble in the liquid. In this case, it is not.

Second, can any of those methods for accelerating precipitation be done with the things that you can reasonably carry into an airliner bathroom?

Sure, some can. Whether or not they would work for this particular preparation, I don’t pretend to know. One method, for example, is to add a flocculant; another chemical which causes the microscopic crystals to clump together quickly as they form, so that they settle out faster. I do not know if any suitable flocculant exists for acetone peroxide, but if it does, using it would likely be a simple process of adding it to the solution after the main reaction has completed.

There is another method which I think is very likely to work, and would require even less effort on board the aircraft, but I don’t care to describe it here.

In any case, I just had a look at some primary sources and it appears the long precipitation is only required to get a efficient yield; most of the precipitate forms in just 1 hour.

Finally, a picture of an airliner’s bathroom for reference.

Yep, I’ve seen one before.

@J.D. Abolins :

here’s The Register’s take on it:

What an awful article. Greene has obviously made up his mind beforehand, and is trying desperately to prove his case, presumably to promote some agenda of his own. Nearly the whole article is either technically wrong or illogical. For example, he seems to almost “prove” that liquid explosives are a Hollywood myth; in reality, they are extremely common, and in some industries liquid emulsion explosives like Gianite, High Jex and Emulite have almost completely replaced solid ones.

He greatly exaggerates the difficulty of obtaining sufficiently strong hydrogen peroxide (while not available at the corner store, you can simply buy it; it’s not a controlled substance). He lists all sorts of accessories which are not in fact essential, claims several trips to the lavatory are required (I would think the entire kit would fit in a small knapsack or a bulky coat), greatly exaggerates the time to complete the reaction (it’s only a few minutes, not hours; precipitation usually takes much longer but can continue in a bag under your seat); uses Aloha Airlines Flight 243 as an example of how tough planes are (most experts cosider the survival of this aircraft to be a near-miraculous unique event, in comparison Pan Am Flight 103 was totally destroyed by just 1 lb of explosive which initially created just a 20 inch hole); and on and on.

Matt D August 18, 2006 8:59 AM

” “Now they’ve evacuated a terminal because explosives were ‘found’ in a water bottle.”
They found residue, not actual explosives.”

On the last news report I saw about this, a couple of hours ago, it said the woman has now been deemed not to be a terrorist and had been allowed to continue on her journey. The bottles were being retained for further analysis.

If it’s a genuine false alarm, several possibilities spring immediately to mind, including contamination from nitrate based fertilisers on the bottles, nitrate contamination to drinking water /in/ the bottles.

News reports claimed that both a machine detector and a sniffer dog had found explosives, which suggests something ‘common’, rather than more exotic compounds – dogs take time and a lot of money to train.

Then again, the news reports also mentioned that the woman was a US citizen of Pakistani origin. Driving whilst black, anyone?

Doug Watts August 18, 2006 1:35 PM

The US and UK administrations both have a proven record for lying to the public in matters of national security and their possession of “evidence” demonstrating the need to go to war.

The timing of the “terrorist alert” in the UK was so “coincidental” that it has naturally invited questions as to the veracity of those who made the alert, based on their previous untruthful utterances on the same topic — which had the same ultimate goal as this one.

So without even venturing into the subject of whether the arrested folks did in fact devise a plot to bring an explosive mixture onto airplanes, we can still examine the whys and wherefores of the specific and highly coincidental timing of the “bust.”

If the timing of the “bust” was based mostly on distracting the US and UK people from other matters, that is important information for those of us attempting to discern to what extent the US and UK leaders are trustworthy and can be trusted.

At least thus far, there is reasonable doubt that the timing of the bust was unrelated to the larger, political objectives by the US and UK leaders, ie. that its timing was completely coincidental.

Absent more information, that’s the best I can surmise at present.

Clive Robinson August 19, 2006 9:36 AM

One thing that has not been mentioned about these liquid explosives that is quite important “yield” (ie the amount of usefull exploseve component).

To be effective in doing structual damage to a large object like a 747, an explosion needs to be either quite large or carefully focused and placed (this thinking is probably part of why AirForce one is what it is).

Making high yield binary liquid explosives have two problems (as mentioned above) time and temprature, a third is the yield of usefull explosive from the mixture you make (which is very dependent on the other two).

To shorten the mix time so that is not suspicious (say ten minutes in the toilet) you are going to have to overcome a number of very real problems or accept a yeild that is to low to do any real physical damage.

To overcome these problems you are going to require equipment that is going to be sucpicious in it’s own right (and you won’t make it onto the flight anyway).

You then have two further problems,

1, Putting your liquid charge where it is going to do sufficient damage to bring a plane down.

There are not that many places where a pasanger can get to where you will be able to do sufficient damage.

2, Are you going to be able to do it without being stopped.

Neither the Philapeans Airline Flight 434 (Ramzi Yousef ) or Shoe Bomber (Richard Reid) attack worked as intended.

Is it possible to bring a plane down with liquid explosives mixed on board since 9/11 and RIchard Reid? Possibly but so is factoring a composite number from two primes using a calculator and a pair of dice to gennerate random numbers, the question is which is more probable…

kyber August 19, 2006 11:36 AM

Problem is, science (as in Chemistry) has to be right. A goon engineering a bomb only has to be pretty sure, something that would be unacceptable as scientific thought and therefore is not something that will appear on textbooks. This article limits itself to knowledge that would make a reactor or a lab safe for the operators and the environment; making a device that nobody cares if it “fails” (it is, be dirty, messy and not give any kind of warranties at all) is several orders of magnitude easier.

Clive Robinson August 19, 2006 8:42 PM


“Problem is, science (as in Chemistry) has to be right

Actualy that’s secondary, the first problem is physics.

To do any damage to an object requires a certain minimum of energy to get it past the plastic limit of the materials it is constructed of. The energy also needs to be released in a given time frame (power = energy / sec select your own prefered units of mesurment).

The energy is applied to the object via some kind of force (which has direction) workng in a transmission medium.

If the transmission medium is deficient (and in practice they all are) then the amount of effective energy transfered to the object is reduced. Also as a general rule, when energy is converted from one form to another it lacks direction and will radiate uniformally in a constant medium. Therefore to get an effective force you need to focus the energy in a given direction.

In general the more dense the transmission medium the easier it is to transmit mechanical energy, and the less likley it is to transform the energy into a less usefull form. As all transmission mediums are defficient in one way or another it is best to minimise them.

In essense if you want to destroy an object the best way to do it, is to do your energy conversion in the center of mass of the object (ie drill a hole in it and put your explosive inside).

The second best method is to have the energy conversion foused towards the object to be destroyed. At it’s simplest strap the explosive to the side of the object nearest the center of mass, and put a focusing object on the other side of a high mass and density to direct the force. You can also use the explosive it’s self as the focusing mechanisum which is basically
what a shaped charge is. However you do get an improvment by actually moving the charge off of the object a small distance to allow the force to focus to an optimum. Also converting the shaped charge into a plasma jet device can be more effective if you wish to cut or penetrate an object.

The third best and that which is used when the explosive is not in close proximity to the object is to focus the force onto an itermedury object which transferes the energy to the destination object. An example of this is the newtons cradle or a gun. In warfare you would use a shapnel grenade mortar or Iron bomb, the explosive partialy fills a void inside of a high density casing, which is designed to focus the force of the explosion for optimum effect in radiating the casing pieces.

The least effective way is to just pile the explosive up and set it off and use the blast wave to do the damage (air at sea level preasure is a very bad transmission medium).

As you work your way down the list the amount of energy you have to release to destroy the object goes up (dramatically).

All of the above (apart from the plasma jet) uses simple physics that Newton would have understood without problem.

Esentially all a conventional explosive is a heat engine that causes the rapid expansion of gasses. The rate the explosive burns at usually determins it’s type. Burn rates above the speed of sound (at atmospheric presure) are generally clasified as high explosives.

The reason high explosives are so effective is that due to the speed the blast wave moves at, air ceases to behave as a compressive gas and behaves more as a fluid. The propergation rate of the wave front where the air is being compressed is actually considerably slower than behind it where the air is compressed (increased density gives hiher speed of sound). The result is the energy of the explosion is held at the blast wave front as a shock wave (and is just a few atoms thick). For the physics of this see,


Then you come to the bit of physics that crosses over into chemistry,

In the everyday world the storage of energy is usually (for conveniance and safety) chemical in nature. Basically each molecule consists of two or more atoms that are joined by “chemical bonds” and it is in these that the energy is stored and released. The bonds can be Ionic, Covalent, Hydrogen & Metalic. For more info see,


There are generally three problems with storing energy using chemical bonds, getting the energy (endothermic reactions) in to the molecules keeping it there and getting it out in a controled/desirable way (exothermic reactions).

As a very generalised rule of thumb, the more energy there is to be released by the making of a chemical bond the worse these problems are.

Exothermic reactions result when the chemical bonds between atoms in molecules are either reformed or when the overall result of a reaction between two molecules is the making of new bonds.

If you want a very high value of energy stored per unit volume you have two options. Either go for chemical bonds with a high energy per bond (bond energy), or go for atoms with a high number of potential bonds (valence) with a lesser bond energy per bond.

If you want to get the energy out quickly and easily then the type of chemical bond is very important. You will be looking for an exothermic reaction which releases large amounts of bond energy very quickly. There are two ways to make a high energy storage substance of this type (ie an explosive).

The first (and most dangerous) is to use a single molecule type (Primary Explosive) which is very unstable as the molecule contains both a fuel and oxidizer (fulminates, nitrates of simple organic compounds etc). They require little or no energy input to get over their entropy point and often release the energy spontaniously. The more stable of these chemicals are usually reserved as initiators or primers (in detornators).

However making of these chemicals can be a downright dangerous task especially as some of the chemical reactions are sufficiently exothermic to cross the entropy point of the developing molecules. Usually you need to make these in “ice baths” or other cooling mechanisums.

The making and transportation of Tri-Nitro-Glycerine (TNG) known originally as blasting oil was so dangerous that it was often made near the place it was to be used and fatalites in the workforce was in the tens of percent. It was only after Alfred Nobel found a way to stabalize it with kieselguhr (an inert clay) to make dynamite, that the comercial use of explosives became common, for mining and tunnel making (and in the US for killing cattle for meat production…).

The second and more stable is a physical mixture of differnet molecules such as a fuel (reducing agent) and it’s oxidizer (Secondary and Tertiary Explosives). A common example is benzine and atmospheric oxygen (car engines and fule air explosives). Usually these mixtures require a much larger input of energy to get over the entropy point. In some cases (C4 for instance) the compound can be used as a fuel for cooking food or as an explosive.

Often the oxidization rate can be improved by the addition of a catalyst, gunpowder for instance is a mixture of this type, potassium nitrate (the oxidizer) powdered charcoal (the reducing agent), and sulfur as the catalyst.

When strong oxidizing agents are mixed with strong reducing agents, energetic reactions (such as explosions) commonly result. The problem is that the making of these agents is of itself extreamly dangerous as well.

macxlii August 22, 2006 11:30 AM

The aspect of airplane terrorism using liquid explosives that is most frightening is that liquid explosives such as emulsion explosives (ANFO) have been well known for a long time and now we find that the terrorists could have carried them onto the plane any time, in bottles labelled hand lotion, body balm or what have you. The failure to take precautions against this very real danger while making us give up nail clippers is a measure of amazing official shortsightedness and chronic bumbling (from those great people who gave you the Hurricane Katrina rescue efforts). Do we have groups set up to think of how the next attack might be mounted? Is it possible that the terrorists might learn how to make efficient explosives in the form of Lego (R) bricks, locked together to form a compact mass to be exploded by a suitable detonator-timer? “Yes, officer, they are a present for my dear little children and that is my wake up alarm to see I do not miss my flight.” About time to see that carry-on luggage be limited to immediate flight necessities and to think if the checked luggage can really be “checked”.

kyber August 22, 2006 1:43 PM

Clive:”To do any damage to an object requires a certain minimum of energy to get it past the plastic limit of the materials it is constructed of”

Point well taken. However, the goon doesn’t have, as I said, before, to be sure; there is a chance that the object to be damaged is already on a bad shape. Engineers need a confidence on that their design will not break; somebody breaking stuff only needs a pretty good chance to slip through some defect. In the field all numbers and calculations are off, the simulation can say “most probably this won’t work” but a goon will place its bet on the remainder.

Parkingtigers August 26, 2006 2:37 AM

By the way, the “explosives in a water bottle” incident turned out to be residue of make-up. Yup, two tests said it was explosives before they could work out that it was actually just cosmetics.

Seymour August 28, 2006 7:56 PM

I second the guy who said “if terrorists wanted planes to fall, they’d be falling”.

Its amazing how many get lost in the obscurities of explosives chemistry and miss the big issue completely – that being in whose interest is it to script arrests of fake terrorists with unbelievable plans?

Daniel F April 6, 2007 7:31 AM

If you want to see some information from the real guy who designed this idea is in the following document:

“May 19, 1996, “kite??? from Ramzi Yousef to Greg Scarpa Jr. entitled “How to Smuggle Explosives Into An Airplane.??? The note suggests several alternatives to nitroglycerine as a high explosive, including RDX and “acetone peroxide,??? later suspected by British authorities of being one of the key ingredients in the August 2006 transatlantic airliner
bombing plot.”

Page four of this document has a list of
chemicals etc:

Page five “the watch from Photo of the actual Casio-nitro bomb trigger seized from Yousef ’s “bomb factory,??? Room 603 at the Dona Josefa apartments in Manila. Its design was a precursor to the schematic in Yousef ’s kite.”

Location on the plane: as close to the fuel bays as you can get. Perhaps the
myth busters can see what works.

Jim October 21, 2008 8:29 PM

I have given this quite a lot of thought and perhaps the goal was not to create an explosive. But perhaps a liquid incindery device as concentrated peroxide will react violently with common organic fibers (cotton/ leather) upon contact. Combined with a source of fuel and sprayed out of a bottle onto the floor, chairs or other passengers the result would be a horrific high temperature fire. At the minimum there would be a few deaths if not complete destruction of the plane, due to internal fires.

Also BTW I don’t think anybody here has mentioned that formation of Acetone Peroxides requires mixture in a -10deg C ice bath, as a way to avoid run away reaction temperatures. Its important to mention that Peroxide above 70% will form explosive vapors when heated little above 70deg C. This is highly undesirable if the goal is to precipitate a useful yield of explosives. Formation of said bath would require dry ice and pure ethanol, another difficulty to achieve in the aircraft toilet.

Binary explosives or mixes might be achievable but hard to initiate sans an explosive detonator, and you just cant walk onto any plane with detonators.

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