‘Clean bombs’ may be the new focus of explosives detection
Rep. John Mica (R-Fla.), chairman of the House Aviation Subcommittee, says the type of bombs that the alleged London terror group intended to use to crash planes into the Atlantic (see govtsecurity.com/news/AirlinePlot/) probably would have slipped through airport detection devices armed even with the latest technology.
“This is a new approach to destroying our aviation system using what I call clean bombs or explosive components to take down multiple aircraft,” Mica says. “We face a very serious challenge in that regard. If they get to the checkpoint, our chances of detecting them are limited.”
U.S. and British authorities have refused to identify the specific components that the terror suspects planned to carry aboard planes. A senior U.S. intelligence official with knowledge of the investigation told USA Today that the explosive they had chosen is called hexamethylene triperoxide diamine (HMDT) and is based on hydrogen peroxide.
Common liquids found in the home, including hair bleach and food preservatives, could be processed, then combined on board a plane after takeoff, to make HMDT.
The typical methods used to detect explosives at airports — swabs that test the exterior of luggage and explosive detection machines — would largely be useless against such common ingredients.
Dogs are often the last line of defense against bombs, but they can only detect chemicals they have been trained to recognize, the USA Today report says. They may not be able to detect chemical components of a bomb.
While all checked bags bound for a jet’s cargo hold are screened for explosives, the vast majority of carry-on bags are not. Carry-ons pass through X-ray machines, which may be able to detect the wires in a bomb’s detonator, but can’t show whether a bag contains explosives.
Passengers also must pass through metal detectors before boarding a plane and their shoes are X-rayed. Virtually no one is checked for explosives.
“This is the greatest vulnerability that we have,” says Rep. Peter Defazio (D-Ore.), the ranking Democrat on the Aviation Subcommittee.
Although common household cleaners and other liquids can be used to create explosives, it’s not as easy as it sounds, says Neal Langerman, a chemist with the American Chemical Society.
“It’s something of a misstatement to say that because liquid explosive components are commercially available that anyone can make them,” Langerman tells the newspaper. “One component you might be able to get at Home Depot, but the other one would require a chemist to purify and jump through the whole process.”
Even then, the process would be inherently risky for anyone trying it, he adds.
Sulfuric acid used in drain cleaners, hydrogen peroxide and nail polish remover are some of the ingredients found in bombers’ recipes. But at least one of the ingredients in a bomb typically requires chemical refining to purify it — a difficult and dangerous process, Langerman says.
Current airport tests are “not designed to pick up most liquid explosives,” says chemist Jimmie Oxley of the University of Rhode Island.
Mica says he asked government security experts to test whether the component parts of a bomb — which could include simple ingredients such as concentrated hydrogen peroxide and camping stove fuel — could be detected.
Be sure to check out the August issue of GOVERNMENT SECURITY, which features an in-depth look at airport and rail security. Included: R. William Johnstone of the 9/11 Commission explains what’s wrong with transportation security.