Tagging explosives

2012-01-05

in Bombs and rockets, Geek stuff, Politics, Security

On a television show I was watching, they mentioned that C-4 explosive is tagged in a way that aids the tracing of its origin if it is used in an illicit way like in a terrorist attack.

Possible method of tagging

I have no idea if that is true, but an idea did occur to me about how it could be done if an organization wanted to. What you need is a collection of chemicals that are stable – that can survive an explosion – and which are rare and can be detected individually. Say you have a set of six such chemicals: A, B, C, D, E, and F.

Each is essentially one bit of data: a zero if absent in the explosive in question and a one if it is present. With six bits of data, you could then label 64 different batches with a unique combination of those chemicals. They would range from 000000 to 111111.

As the number of chemicals used increases, the number of distinct batches you can tag increases rapidly, according to the formula 2x, where x is the number of different chemicals used.

After undetonated explosives or an explosion is found, tests could be administered to detect the presence or absence of the marker chemicals. Based on the combination of chemicals present, the marker could be read.

Uses of tagging

If you had a couple of dozen distinct chemicals, you could label a huge number of distinct batches. You could have factories making the stuff identify whether it was sold for civilian use or military use, where it was to be initially sold, etc. You would then have a forensic ability to trace back the explosive to the point of manufacture and maybe identify who was the final user.

This could be especially useful if you suspect a legitimate customer is illicitly trafficking in explosives. Say you suspect a mining company of providing explosives to paramilitary groups, or you suspect an allied country of providing explosives to armed rebels in another country. You could make sure to provide the suspect entity with a specially tagged batch, and then you could take samples at sites of suspected use and look for the markers.

Of course, you could also get caught in the act yourself if you got careless. Someone could work out your marker system for themselves or buy information about it from someone who knows. Then, they might be able to find cases where you were redistributing explosives yourselves through illicit channels.

Also, there will always be some homemade explosives like triacetone triperoxide (TATP) that groups will have access to, but denying them the ability to make covert use of explosives manufactured for legal military purposes or commercial use could nonetheless be valuable.

Report a typo or inaccuracy

{ 4 comments… read them below or add one }

Milan January 5, 2012 at 8:30 pm

You definitely don’t want to handle TATP:

“The mixture must be kept below 10 degrees Celsius. If the crystals form at this temperature, it forms the isomer called tricycloacetone peroxide, which is relatively stable and safe to handle. If the crystals form above this temperature, the dimeric form, called dicycloacetone peroxide. This isomer is much more unstable, and could go off at the touch, making it not safe enough to be considered a practical explosive. As long as the temperature is kept below 10 degrees Celsius, then there is little to worry about.”

The trimer is the more stable form, but is not much more stable than the dimer. All forms of acetone peroxide are sensitive to initiation. Organic peroxides are sensitive, dangerous explosives; due to their sensitivity they are rarely used by well funded militaries. Even for those who synthesize explosives as a hobby there are far safer explosives with syntheses nearly as simple as that of acetone peroxide.

coyote January 6, 2012 at 6:42 am

Yes, many of the modern explosives really are traceable. C4 has been tagged for some years, I imagine with a variant on this process, or similar. . .

Anon January 6, 2012 at 10:33 am

Something similar could probably be done with fissile materials like plutonium.

You could add rare isotopes as markers, possibly using the half lives as a further forensic tool.

. June 19, 2017 at 1:43 pm

NRC Panel Enters the Fight Over Tagging Explosives

The idea sounds simple enough: Add chemical “tags” to explosives to help detectives sniff out bombs and track down bomb-setting criminals. Calls for implementing such plans have cropped up for decades, usually after well-publicized bombings when the public is anxious for some kind of action. The pressure was on again last year in the wake of the Oklahoma City and Atlanta blasts, and this time it prompted Congress to ask the National Research Council (NRC) to study the matter. But a workshop held last week by the new NRC panel showed just how difficult it is going to be to settle on a workable plan.

Proponents of tagging schemes, largely from companies hoping to sell “taggants,” contend that proven systems now exist that can safely tag everything from high explosives to fertilizers to gasoline, all for as little as $5 per ton of bomb-making material. By reading the tags, investigators could track explosives to their point of purchase or theft, narrowing their suspect lists. And while earlier tagging schemes required salting the explosive with foreign objects, perhaps affecting its stability, chemists now have come up with subtler methods relying on everything from snippets of coded DNA or heavy-isotope twins of molecules already found in explosives.

Manufacturers and other industry groups argue, however, that even these new tagging schemes are costly and would swamp manufacturers with paperwork for tracking the movement of millions of tons of chemicals. Even law enforcement officials question whether it’s the best way to spend scarce funds. Says J. Christopher Ronay, former head of the FBI’s bomb squad, who now serves as the president of the Institute of Makers of Explosives (IME) in Washington, D.C., designing a nationwide tagging program “is no slam dunk.”

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