Old Methods Used to Detect Liquid Explosives

Bain writes "According to Wired News, the UK fear of terrorists using liquid explosives could be dramatically reduced by the use of some very old tech. Recent events have seen passengers forced to pack only the barest of essentials into clear plastic bags and the restriction on all liquids force even mothers with young children to have to test bottled milk to prove that it isn't a dangerous liquid." From the article: "For a machine to detect explosives in liquid or solid form, it bombards an object with energy -- such as radio waves or neutrons -- and in seconds measures the reaction, a response that differs depending on the material's chemical properties. Software in the machine is programmed to alert screeners if it detects chemical signatures known to match those of dangerous materials. A key question, though, is whether this kind of detection system can realistically block terrorists from bringing seemingly innocuous liquids past security and combining them later to deadly effect."

Comments

False positives and common materials

[generic-man]

From the article:

"Homeland security analyst Brian Ruttenbur of Morgan Keegan also points out that the technology still produces a relatively high number of false alarms."

and

"A key question, though, is whether this kind of detection system can realistically block terrorists from bringing seemingly innocuous liquids past security and combining them later to deadly effect.

"Certainly, some common ingredients in liquid explosives can be programmed into the detector. But Kant, at Rapiscan, said he would not discuss the vulnerabilities of that approach. 'Whether it detects the components of explosives and which ones, there's no way I'm putting that in print,' he said."

We still allowed fertilizer to be transported by truck after the Oklahoma City bombing. I really don't know how we can expect people to transport any substance by airplane if there's even a slight chance that it could be used in a clever bomb-making scheme.

The old sniff sniff bark method

[gr8whitesavage]

Why can't man's best friend, the K-9, sniff out these liquid explosives instead of buying a $250,000 "puffer"?

Re:Basic Chem Pwns Bin Laden

[Rachel Lucid]

We're not talking about stink bombs here...

Besides, organic peroxide explosives do not react with the human body well. I think anything that could be urinated is either too neutral for bomb-making purposes or needs a strong base to react with, and anything 'too strong' would kill the attempting terrorist prior to 'detonation'.

Even?

[Distinguished Hero]

the restriction on all liquids force even mothers with young children to have to test bottled milk to prove that it isn't a dangerous liquid.

This isn't a matter of "even;" it's a matter of "especially." See this story; quote: "A HUSBAND and wife arrested in the British terror raids allegedly planned to take their six-month-old baby on a mid-air suicide mission. Scotland Yard police are quizzing Abdula Ahmed Ali, 25, and his 23-year-old wife Cossor over suspicions they were to use their baby's bottle to hide a liquid bomb."

Re:Basic Chem Pwns Bin Laden

[AJWM]

Quite possibly. I haven't seen anything definitive on what they were planning on using, but I've seen suggested that it was acetone peroxide (or rather triacetone triperoxide). Acetone is indeed both volatile and stinky, and you need pretty highly concentrated peroxide (read "unstable") to get a decent reaction rate.

(As for acetone peroxide itself -- yeah, pretty exciting stuff, and doesn't need anything special in the way of detonators that a lot of the more stable nitrate-based explosives do. And because it isn't nitrate based, isn't detected by the nitrate-sniffers used in a lot of bomb detectors. I had a chance to play with a few grams of the stuff once (in its powder form). It doesn't take much confinement to go from "whoosh" of a fireball to "BANG!" of a detonation.)

Plenty of other possible liquid explosives too, of course. (Nitroglycerine is a liquid, although not one I'd want to carry around in a Gatorade bottle.)

Companies from the article

[rchatterjee]

Here are the web sites of the two companies mentioned in the article.

Rapiscan Systems

and

HiEnergy Technologies, Inc.

They both have interesting product portfolios.

Re:Is it THAT big a problem??

[LurkerXXX]

Apparently you've never had them lose your luggage. I have. Keeping your toiletries in your carry-on is a good idea (if they will let you nowadays...)

Yeah, most places you land will have a store you could get most/all of the stuff in, but usually when I travel for business I'm busy with meetings, and don't have time for shopping. And when I travel for vacation, I'm there for vacation, not shopping. I don't travel hundreds/thousands of miles and burn vacation days, just so I can shop at the local K-Mart.

Re:Basic Chem Pwns Bin Laden

[Cyberax]

Even better, you can make acetone peroxide from fairly household chemicals. And you can pack enough of it into notebook battery. Just imagine, you open notebook and the whole plane explodes.

I've always wondered why acetone peroxide was not used in airplane bombings. Now my thoughts are answered :)

Another cool method to explode airplanes may be by using alkali metals to produce hydrogen and make a volume explosion, 100-200 gramms of lithium will be quite enough to blow up an airplane. The best way to produce hydrogen is to dump metal chips into a bottle of 98% alcohol - lithium reacts with alcohol much slower than with water so hydrogen does not blow up immediately without reaching sufficient concentration.

It's fortunate that terrorists usually have no imagination.

Re:Is it THAT big a problem??

[drinkypoo]

While I do not have on hand statistics for luggage theft for the past several years, I doubt many people would entrust such devices to checked luggage, even before locking said luggage was discouraged - seriously, did the people who tought that up think the thieves and smugglers retired?

The clueful among us long ago invested in a $10 TSA-approved combination lock. These locks have both a combination and a keyhole; the keys are held by the TSA agents, and anyone who has managed to get a copy of one. However, it's a lot better than no lock.

Re:Basic Chem Pwns Bin Laden

[cirby]

Actually, the amount of TATP you could put inside a notebook battery wouldn't be enough to blow a modern jet out of the air, (unless you got really lucky). It's a decent explosive, but not that powerful, and not very dense (you couldn't get that much inside a battery). You also need a more-definitive trigger, since they make you open up laptops and boot them at many airports.

A hydrogen explosion would be hard to manage, since you'd need a whole lot of it, and need to confine it somewhere in just the right concentration.

The "innocuous chemicals" bit mentioned in the article is pretty misleading, too. "Innocuous" only goes so far, since acetone (for the lighter stuff) or nitromethane (for the heavier stuff) aren't innocuous to even the most casual inspection, and are HAZMATs in themselves.

The fact that the bad guys tend to use TATP as an explosive is actually a good thing. It shows that their technical skills are pretty minimal, since they'd be using better explosives like nitroglycerine over TATP if they had the choice (more powerful and less sensitive to shock).

Re:Basic Chem Pwns Bin Laden

[Dun Malg]

especially in a closed, delicate system. Like an airplane in flight.

The inside of an aircraft isn't a closed system. The engines compress outside air and feed it in at the front of the plane. At the rear of the plane are pressure-valved exhaust vents. It's needlessly expensive to recycle the inside air when the outide air only needs to be compressed to 10psi to make it breatheable. A chlorine bomb would probably injure a few passengers right around it, but that's it. Being that the cockpit is "first in line" and gets its air straight off the bleed air system, there's no way to gas the crew.

A shaped charge obviates this

[WillAffleckUW]

Actually, the amount of TATP you could put inside a notebook battery wouldn't be enough to blow a modern jet out of the air, (unless you got really lucky). It's a decent explosive, but not that powerful, and not very dense (you couldn't get that much inside a battery). You also need a more-definitive trigger, since they make you open up laptops and boot them at many airports.

Wrong. Basic first-year explosives training involves how to use and create a shaped charge, and quite frankly, your tray table converts quite handily into a usable weapon, as would any standard men's belt. You just need to have a cover material to shape the charge (hmm, like the rest of that tray table with some easy pad inserts that stick on), slap it on the door, and you're inside the cockpit.

Look - the problem isn't that they're using liquid explosives - heck, both sides used them during WW II in certain situations - it's that they're well trained and know what they're doing.

The most effective way of stopping them is using this object called a "blanket" or a "coat" and shoving it on top of them and jumping on top, and stopping them from getting any closer. Any resulting explosion will go into the base of the plane, and only damage - at worst - minor steering to the tail - and there are redundant systems just for that reason.

Just stop worrying and if someone tries to assemble such a bomb, just throw a blanket on them, pummel them, and call for the stewards and stewardesses. That will solve the problem.