Aerosol Spray to Identify Bombing Suspects

RedHanded writes "Forensic chemists at the Hebrew University of Jerusalem have developed a color-changing spray that can identify people suspected of making or planting bombs. The chemical turns from yellow to bright red when it comes into contact with urea nitrate, an explosive residue that may be left behind on the hands of someone who has handled an improvised device."

Re:Basic hygiene

[Upaut]

Only if this person with bad hygiene sweats nitric acid...

I'm more worried about, well, me... I use urea nitrate in my tropical orchid mix...

Re:Basic hygiene

[Neanderthal Ninny]

How many people in their lifetime ever actually handle urea nitrate anyways? In my previous career I used to handle explosives and most explosives your don't want to handle with your bare hands since most of them are a health hazard also, not to mention the blasting power. The nitrates in the most explosives are basal dilators so you turn bright red because all of the blood vessels in your body are opening up. You may identify people that handle explosives this way but alcohol does the same thing so don't count on it.

Re:Basic hygiene

[battery111]

Well, not exactly. I don't know enough about how the chemical works (it will likely be found to cause cancer in the state of california at a later date), but part of manufacturing urea nitrate is indeed to distill ones urine. My guess is that it would have to be at a relatively high concentration in order to react, but that may not be the case, which would cause a large number of false positives. Another thing to keep in mind is that urea nitrate is only one of a large number of homemade explosives, and not really the most common, so while it is a promising advance, it really is not the be all end all of bombmaker detection. One also has to raise questions about its effects on personal privacy, but likely in the areas this is going to be employed, it may be a secondary consideration.

Re:Basic hygiene

[Kingrames]

More importantly, are there going to be people who walk around in airports spraying random people?
This is why I stay away from certain areas of the mall.

And more importantly, what will happen when someone yells "Security! This man is assaulting people with aerosol spray!" and the airport undergoes lockdown?

Or more feasibly, what happens when the terrorists use the aerosol as an opportunity to walk around the airport spraying people's hands, infecting them with SARS or some other horrifying disease?

Seriously, these people need to find an alternative way of doing this. it opens up too many scary options for abuse.

Re:Basic hygiene

[rve]

The Birmingham six were convicted largely based on the result of such a test.

http://en.wikipedia.org/wiki/Birmingham_Six/ [wikipedia.org]

Indicator tests are nothing new by the way, and they're not inherently useless, as long as you realize that they tend to be non-specific, and usually react with a whole range of compounds. If you have a sample that you know may contain either substance A or B, and you know only substance B reacts with your color spray, then the reagent is a quick and reliable way to tell the difference.

If on the other hand you start spraying it on people who may have been in contact with any number of substances, and then accuse anyone with a positive reaction of terrorism, innocent people are going to end up in jail.

Re:Just another excuse

[intothenight55]

You have got to be kidding me!!! Laws are not made to oppress, but because we, I say WE have seen in the past where someone or something infringed on someone else's rights and caused harm to innocents... Laws are placed for that not to happen... In the free society you speak of I would be allowed to come over there and kick the hell out of you and expect no consequences, or purchase the high explosives that I want and create a crater of glass around you!! I'm not even saying you are wrong but the utopian society you speak of will never exist we need laws to keep control of the idiots down the road and prevent future crimes... I do however have a problem with you thinking that it is a miniscule threat, PEOPLE dieing is not very miniscule... the false positives are worth it... if it saves 15 or 20 American's lives it will be worth it.. You call this a "witch hunt" it's not a witch hunt it is a serious problem.

Touchy subjects I know but worth a thought... Would you like to know that every postman could get their hands on high explosives? Could you imagine what would have happened if the kids in Columbine could have gotten their hands on high explosives?

Heart medication

[phorm]

I remember somebody I know telling me about how she was stopped and searched, etc at the airport because she had traces of nitro on her hands and in her purse. Now why would she have that? Well her husband used it as a medication [medicinenet.com] for his bad heart.

You'd be surprised at the rather harmless (explosion-wise anyways) uses many of these chemicals have, and I'm sure the airport guards may be as well. I've heard many cases of funky medications giving weird results in various situations. Did you know that taking a breathalizer test shortly after pumping ventalin (for asthma) will often result in a false positive?

My friend heard this and decided to test it with a police officer (first by passing the test, then by puffing and taking it again). They were both quite surprised at how much it skewed the reading. The officer basically stated he'd never heard of such a thing, but he'd definitely keep it in mind and pass it along to others for future reference as in a situation where he had not watched her puff and taken the earlier reading my friend would have been on her way down to the station on DUI charges.