In March, suicide bombers in Brussels killed dozens and injured hundreds more. Their dramatic attack caught the world’s attention, but the material used couldn’t have been more ordinary — an explosive called TATP that can be made by distilling the same hydrogen peroxide sitting in your medicine cabinet.
Jimmie Oxley at the University of Rhode Island thinks she has an idea that could make such attacks far more difficult to execute — and she has filed a patent for it. The idea is to mix hydrogen peroxide with trace amounts of additional chemicals, so that it retains its usefulness as an antiseptic, but can no longer be distilled to make a bomb.
“We found certain additives, at a very small level, just one or two parts per million, can keep [terrorists] from concentrating [hydrogen peroxide] the normal way they’d do it,” Oxley says.
Oxley’s work takes place under the aegis of a research group called ALERT — for Awareness and Localization of Explosive Related Threats — that is funded by the Department of Homeland Security. ALERT involves researchers at 13 universities, including URI, Northeastern, Tufts, and Boston University, who are working on technological advances to help thwart terrorist attacks. These range from improvements in airport scanners and video monitoring, to new ways of training bomb-sniffing dogs. They also feature strategies for what’s called “precursor control” — ways to prevent terrorists from getting their hands on bomb-making ingredients in the first place.
Precursor control crops up most familiarly in pharmaceutical sales, where there are safeguards in place that prevent people from buying products in bulk to make drugs like methamphetamine.
“The obvious way is stop selling them and you’ve seen that ... the last time you had a cold and wanted pseudoephedrine and you had to sign at the counter,” says Oxley.
Limiting access to chemicals is one way to achieve precursor control. The other is to adulterate chemicals so they can’t be used for undesirable purposes. A common example of this is the way 100 percent ethanol is manufactured — it’s “denatured” with the addition of a little benzene, which keeps it useful for chemistry labs, but prevents it from being consumed as alcohol. Such subtle tweaks in a product’s chemistry are hard to find, however.
“The chemistry of each individual chemical has to be understood if you’re going to find something that prevents it from reacting and being made into explosives,” Oxley says.
In 2013, Oxley and her collaborators discovered one such approach that neutralizes hydrogen peroxide. By adding trace amounts of a certain metal salts that are generally regarded as safe for human use, Oxley found she could change the chemistry of hydrogen peroxide so that when heated, it decomposes instead of concentrating into an explosive powder.
Oxley’s recipe for hydrogen peroxide has not been put into industrial use yet. This is because, she says, peroxide-based explosives aren’t such a problem in the United States that the federal government has felt the need to mandate the change. She’s also done work on fertilizer (so far there seems to be no way to neutralize it as an explosive on a large scale) and some private work for chemical manufacturers who anticipate their products could eventually get dinged by federal regulators for their explosive potential. In all this, the goal isn’t to make DIY-bombs impossible to achieve. It’s simply to tilt the odds slightly more in favor of security.
“There’s always a way to get around it. Talking to counterterrorism folks, they say, we just want to slow them down,” says Oxley.
Kevin Hartnett is a writer in South Carolina. He can be reached at firstname.lastname@example.org.