Volume 94 Issue 38 | p. 7 | News of The Week
Issue Date: September 26, 2016 | Web Date: September 20, 2016

A look at the explosives used in the New York bombing

Some reports suggest bombs contained a combination of Tannerite and HMTD
Department: Science & Technology
News Channels: Organic SCENE
Keywords: Tannerite, HMTD, explsoives, bomb, ammonium nitrate, aluminum
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New York City Mayor Bill de Blasio and New York Governor Andrew Cuomo stand over a dumpster mangled in the Sep. 17 bombing.
Credit: Justin Lane/Newscom
Bill de Blasio and Andrew Cuomo stand over a dumpster mangled in Sep. 17 bombing.
 
New York City Mayor Bill de Blasio and New York Governor Andrew Cuomo stand over a dumpster mangled in the Sep. 17 bombing.
Credit: Justin Lane/Newscom
A structure of hexamethylene triperoxide diamine.
 

Initial reports about a device used in Saturday’s bombing in New York City suggested the explosive could have been a commercially available material called Tannerite. Stories from the Associated Press and New York Times reported the claim, citing anonymous officials involved in the investigation of the attack that injured 31.

But, on the basis of the material’s properties, explosives experts and the makers of Tannerite doubt it alone could have caused the explosion. A subsequent report from the New York Times seemed to confirm these doubts, indicating that officials had detected the explosive hexamethylene triperoxide diamine (HMTD) in devices related to the attack.

The suspected bomber, Ahmad Khan Rahami, was arrested after a shootout in New Jersey on Monday. He allegedly set off bombs in New Jersey and in New York on Saturday. According to news reports, anonymous officials identified Tannerite at the New York bomb site, and a second report linked HMTD to both bombings.

Tannerite, made and sold by Tannerite Sports, is used to produce exploding targets for long-range shooting practice. The targets explode when hit by a bullet, allowing shooters to hear and see that they’ve successfully made the shot. Occasionally, “tannerite” is used to describe similar products.

An exploding Tannerite target consists of an 8:1 ratio of oxidizer to catalyst, which come in separate containers and are mixed and shaken together prior to use. The Tannerite patent says that, in the optimal composition, the oxidizer contains 85% ammonium nitrate powder by weight, and 15% ammonium perchlorate. The catalyst is 90% explosive grade aluminum powder, 5% titanium sponge, and 5% zirconium hydride.

Jimmie C. Oxley, an explosive specialist at the University of Rhode Island, says that using Tannerite wouldn’t require chemistry training. “It is one of the less hazardous explosives to work with,” she says. But she doubts it was the sole explosive used in New York.

“It is impossible,” says Daniel Tanner, CEO of Tannerite Sports. Only a high-velocity bullet travelling at a minimum of 610 meters per second can trigger their exploding targets to go off. Tannerite is also resistant to fire, friction, and hard impacts. It cannot be merely jolted into exploding, suggesting that normal bomb triggers wouldn’t set it off. Furthermore, Tanner says finding aluminum or ammonium nitrate residue isn’t enough to say Tannerite was used. “Tannerite is not a compound,” he says. “It is a trademark.”

“Tannerite is not going to go off by itself,” Oxley says. “It is very stable stuff. You are going to have to put a strong initiating shock into it. And that could be provided by HMTD.”

HMTD is an organic explosive similar to triacetone triperoxide, the explosive used in the 2015 Paris attacks and the 2016 Brussels bombings. “HMTD is not stable and not nice stuff. You can easily set it off,” Oxley says. “To use HMTD there has to be some synthesis involved,” she says. Thus far, there are no reports as to how Rahami could have made or obtained HMTD for use in the bombs.

Anyone can buy Tannerite online or at sporting goods stores and gun shops. It is not regulated by the Bureau of Alcohol, Tobacco, Firearms & Explosives because the oxidizer and catalyst parts alone are not considered explosives. One state, Maryland, bans the sale, use, and ownership of exploding targets without an explosives license.

Law enforcement officials in the past have considered exploding targets as potential sources of bomb-making materials. A 2013 FBI bulletin on exploding targets concluded that they could serve as an alternative source of ammonium nitrate, which was used to make the bombs involved in the 1996 Oklahoma City bombing.


UPDATE: This story was updated on Sep. 21, 2016, with new information about the number of people injured in the New York City bombing.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Comments
Paul Dobrowolski (Wed Sep 21 15:26:57 EDT 2016)
This was an Islamic jihadist terrorist attack. Rahami's own father told the FBI before this incident that his son is a terrorist. Not sure why this story cannot say this.
MB (Wed Sep 21 17:59:48 EDT 2016)
Because someone might be afraid of "offending" any of the large groups representing "diversity". Oh woe is me, me, mee !
Ed (Wed Sep 21 22:27:48 EDT 2016)
Because this is a story about chemistry, not ideology, on a chemistry focused website. There are other articles elsewhere that thoroughly explore possible motives and the evidence for those motives.
C. Canfield (Thu Sep 22 09:21:07 EDT 2016)
Because it's an article about chemistry.
Triazine (Fri Sep 23 15:42:53 EDT 2016)
So you're upset that C&EN is focusing on chemistry and not trying to dog-whistle to the racists and xenophobes? I'm not sure I see a problem here. Good on C&EN!
Paul Dobrowolski (Thu Sep 29 09:36:30 EDT 2016)
No, I am not upset about the chemistry. It was very informative.

I am just frustrated at our press and many political leaders about not giving us the truth about these terrorist attacks. The following article - http://www.thedailybeast.com/articles/2016/09/19/ahmad-khan-rahami-arrested-but-questions-remain-about-bombings.html - was published the day before the C&ENews article was written, should have created enough suspicion to at least say Rahami was a suspected Islamic jihadist terrorist.
Chemiker (Wed Sep 21 17:54:10 EDT 2016)
More pseudoscientific nonsense in the public press. Tannerite requires a very specific high energy initiator. The ACS should be at the front in debunking political nonsense.
Ryan Cross (Thu Sep 22 10:33:33 EDT 2016)
"Only a high-velocity bullet travelling at a minimum of 610 meters per second can trigger their exploding targets to go off. Tannerite is also resistant to fire, friction, and hard impacts."
Joseph L. Hughey, Ph.D. (Wed Sep 21 18:34:36 EDT 2016)
From Wikipedia, Triacetone peroxide is highly sensitive to both friction and shock. i.e. a simple penny firecracker could set it off. When it TAP detonates, it has an incredible shock wave of 17,000 ft per sec (3.3 miles per sec). Such a high explosive obviously has no problem detonating tannerite. However, it is the peroxide that has the greater destructive potential.
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What really concerns me is that quart-sized containers of acetone are readily available at home-improvement stores. Moreover, Hydrogen peroxide as concentrated as 35% is readily available by the pints on Amazon, etc..

We have already seen the horror of this explosive in France. In the USA, the availability of Acetone and Hydrogen Peroxide is a Pandora's Box of disasters just waiting to open. Yet, there is more regulation on over-the-counter decongestants, than that provided for either of these reagents.

As Scientists, should we advise the authorities to restrict these precursors?
John Wrobleski (Thu Sep 22 08:59:24 EDT 2016)
As a scientist I'll repeat, banning inanimate objects is stupid and never has worked, other than to harass law abiding people. For example, I use acetone by the gallon working with fiberglass in my auto body hobby. It's today's ignorant and short sighted government morons that have created the risks we face. Thankfully, many States have reversed draconian anti gun laws and many now have the right to defend themselves and this nation against the acts of deviants. Political correctness continues to protect violent criminals, often putting them back on the streets after arrests. Police often know who the bad guys are, where they are and what they're doing yet spend more time fleecing the general working public for auxiliary revenue. The government should spend more time on Constitutional national security directives and forget about regulating the private lives of law abiding citizens.
Chemwatch (Fri Sep 23 09:39:15 EDT 2016)
In the name of - but not actually for - protecting the so-called "private lives of law-abiding citizens", John Wrobleski has wrongly accused the gun-cotrol lobbies, existing regulations, political correctness, and the much-hated government to make his arguments against regulating certain chemicals thereby missing the main point. Such accusations are nothing new, and are the recycled stuffs that have been used by demagogues in the past, and being used more forecefully in recent months. Such distorted and biased views do not solve any problem, rather make the situation worse, particularly in this political climate.
Richard Taylor (Sat Sep 24 15:01:03 EDT 2016)
As a scientist and a Christian, I agree with John Wrobleski, inanimate objects are not the problem. The problem lies with evil in the hearts and minds of people. God gave us two great commandments. The first was to love Him. The second was to love your neighbor as yourself. I believe prayer is far more effective as a rule then inanimate object control. And when properly applied directly addresses the fundamental problem.
Joseph L. Hughey, Ph.D. (Thu Sep 22 17:20:12 EDT 2016)
As a follow-up to my comment about the public availability of complete sets of precursors to high explosive syntheses, I direct you to the incredible abundance of Youtube videos demonstrating how to synthesize ... and detonate ... Triacetone Peroxide from these common precursors.

Shamelessly paraphrasing Chemiker's comments above, the ACS should be at the front of lobbying our elected representatives into restricting these precursors.

Since the Oklahoma City Bombing, the DHS (Department of Homeland Security) now regulates the sale of ammonium nitrate. Are we going to wait until a Brussels-level disaster happens on our soil, before we take similar action?
Triazine (Fri Sep 23 15:37:53 EDT 2016)
Do we suggest we limit the sale of rubbing alcohol as well? Maybe it would be sensible to limit the sale of large volumes of chemical precursors to dangerous weapons, but you don't need much to make a small explosive. I can't imagine this would be an effective way to make the public safer. Regardless, with the lax gun laws in the US, it is much more common that one will die (in an all too common) mass shooting than from an explosive.
A. Smith (Thu Nov 24 15:07:04 EST 2016)
I guess we should start banning urination because of the potential to make explosives from urine? Joe Hughey, you should embrace and promote the moral fiber that was generated during the biblical era if you want the world to be a better place. Banning things is child's play. Believing in and promoting a greater good is "manning up" for the next generation.
Kevin Seguin (Fri Sep 23 12:25:51 EDT 2016)
I agree with Wrobleski on one point, there will always be a way to make explosives with a few trips to the hardware store, grocery store, sporting goods store etc. Over regulation probably will not solve any problems. However, I disagree with everything else. Gun control laws work and make sense. Not everyone who disagrees with you is an "ignorant and short sighted government moron" Calling out people on "Political Correctness" is now simply a way discredit someone and to justify hate speech. Let's try to be a lot more civil in our discourse. That in itself will solve a lot of problems.
Robert Buntrock (Tue Sep 27 16:46:58 EDT 2016)
Note that the explosive described here is HMTD, not TAP.
Joe Schwarcz (Wed Sep 21 19:31:22 EDT 2016)
Aluminum in this case is certainly not a catalyst. It is the fuel that is oxidized.
Ryan Cross (Thu Sep 22 10:39:02 EDT 2016)
Aluminum was referred to as a catalyst because the Tannerite trademark calls ammonium nitrate the "oxidizer" and aluminum as "catalyst."

Jimmie C. Oxley says that aluminum is not really a catalyst, but the main fuel.
Umar Abubakar (Fri Sep 23 08:22:16 EDT 2016)
I very much agree that there are quite a number of dangerous demonstrations of fire works and some explosive experiment in Youtube that require some careful edition/and or deletion.
Vincent Daliessio (Fri Sep 23 15:32:37 EDT 2016)
Seems to me that chemistry is not the actual problem here.
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