Homeland Security Insider
The Wave of the Future
THE arrest of 24 British suspects in the plot to blowup commercial airlines using liquid explosives made chaos of air travel and raised concerns about airport security worldwide. According to press reports, the suspected terrorists planned to concoct an "explosive cocktail" using MP3 players and sports drinks to simultaneously blow up as many as 10 jetliners bound for the United States from Britain. There are approximately 106 flights per day between the United Kingdom and the United States.
The liquid explosives plot pointed out an obvious hole in our nation's aim at airport security -- one that can easily be fixed by both policy and through technology. It also reminds us that we face a determined and adaptive enemy. We must be no less vigilant at protecting and defending our way of life as these criminals are at destroying it.
The barbaric plot, like others before it, exposed a fundamental fact about our society: that our greatest strengths -- our openness, efficiency and interconnectedness --also can be our greatest vulnerabilities. The liquid explosives plot pointed out an obvious hole in our nation's aim at airport security -- one that can easily be fixed by both policy and through technology. It also reminds us that we face a determined and adaptive enemy. We must be no less vigilant at protecting and defending our way of life as these criminals are at destroying it.
This latest threat leads us to examine whether airports really are safer five years after 9/11. And, more importantly, are we employing the best technologies to reduce the threat of a terrorist attack? Without a doubt, air travel is much safer today than at any time in history. With all of its obvious shortcomings, the Transportation Security Administration is doing a fairly good job protecting air travelers. Likewise, airport security managers are working hard to keep the public safe and to speed us through their facility. And yes, we all know there is considerable room for improvement and much work remains to be done.
In response to this new threat, the TSA banned liquids and gels from carry-on bags and instituted mandatory shoe screening as additional security measures. Despite an April 2005 Department of Homeland Security report to the contrary, TSA continues to insist that screening shoes by X-ray is an effective method of identifying many types of anomalies. The report said that "even a 1/4-inch insole of sheet explosive" -- not detectable by X-ray -- can create the kind of blast that reportedly brought down Pan Am Flight 103, the airliner that blew up over Lockerbie, Scotland, in December 1988, killing 270 people in the air and on the ground.
The most recent liquid explosive plot in Britain was both simple and creative. It is believed the suspects planned to mix a sports drink with a gel-like substance to make an explosive that can be triggered with a common electronic device such as an MP3 player or cell phone. The sports drink can be combined with a peroxide-based paste to create the explosive. This combination does not have the power of conventional explosives, but can be powerful enough to destroy a pressurized aircraft at high altitude.
Rather than detect the explosive directly, screeners are expected to determine if a shoe has been tampered with, such as being hollowed out to fill with explosives. And, examining shoes through X-ray machines doesn't help screeners find a liquid or gel being used as a bomb. There may be value in this approach, but the fact that it does not detect the explosive leads me to believe the whole process is designed more to make us "feel" safe rather than "be" safe.
One solution for detecting the explosive itself may be found in the relatively new field of millimeter wave imaging technology. The term "millimeter wave" refers to electromagnetic wavelengths larger than infrared waves or X-rays, but smaller than radio waves or microwaves to find metallic and non-metallic objects through clothes, including thick jackets or multiple heavy layers. A number of companies are offering promising millimeter wave products, but the one that caught my attention recently is developed by Brijot Imaging in Orlando, Fla.
The Brijot system checks for explosive material hidden on a person without the need for radiation, containment or forcing the person to stand still. It can be installed for use in typical security portal arrangements and also deployed covertly. The millimeter wave component sees through materials like drywall, wallpaper and clothing, allowing the system to be deployed in places where it is least expected. The imaging camera detects suspicious objects made of metal, plastic, ceramic or composite materials that are larger than a user-defined size threshold. It also can determine whether these suspicious objects are shaped like guns or knives, or are of a size significant enough to be a life-threatening explosive.
For federal office buildings or other high-threat locations, the system can provide stand-off threat detection?an operator doesn't have to be in the vicinity of the imaging camera to effectively monitor a subject. Operating from a remote location, the operator can manage the situation by asking the subject via speaker to remove the suspicious object, directing the subject to an isolation location or employing other security management techniques at a standoff distance.
The millimeter wave system can recognize a concealed weapon by using ambient light to process video taken in less than a half second. People entering an airport or other public buildings may be frisked for weapons without them even knowing it. While the system is designed to see through clothing, it doesn't disrobe people like other imaging technologies. Instead, it focuses on objects detected by density.
In addition to weapons and explosives detection, millimeter wave technology also can be used to detect liquids. DefenderTech International Solutions developed a millimeter wave system that can identify the types of containers that might be used to house liquid explosives, even when concealed beneath clothing or body suits and placed in containers made of plastic, composite, ceramic, metal or non-ferrous metal. The system detects devices of the size and materials most commonly used to construct non-liquid, explosive-based bombs. These materials are those that metal detectors and other sniffer-type devices cannot detect.
TSA is correct to use a layered approach to security that relies on multiple methods, including individual searches, metal detectors, X-rays, intelligence, behavior observation techniques, canines, random searches, air marshals, and additional security measures both visible and invisible to the public. We know that no single method of inspection works all the time. A layered approach strengthens the value of security, creating a much stronger, more formidable system. No longer can we rely solely on metal detectors and X-rays to keep us safe, as these systems are unable to detect non-metallic threats such as composite guns, ceramic knives and plastic explosives -- and the bad guys know it. Millimeter wave imaging systems are advancing the status-quo of security. These systems fill a much-exposed void and should be given a close look.
This article originally appeared in the October 2006 issue of Security Products pg. 96.