Bombs Away

By Lawrence Mark Cohen

Interest in bomb detection capabilities is on the rise as the result of heightened fears of terrorism. Recent bomb attacks on the Madrid train network and the British consulate in Istanbul have underlined the need for governments and businesses to consider bomb detection, along with other antiterrorist measures. But before spending limited resources on bomb detection technology, companies must assess both the systems, the potential problems, and their own needs. Following is a look at some of the major considerations and how some of the technologies are being used in facilities today.

Technology options.
Two broad categories of detection technology are trace detection and x-ray technology. They are often used in tandem.

The trace detector is based on ion mobility spectrometry, which picks up on the unique electrical properties of explosive substances, which in turn contain molecules that are especially eager to ionize. When they ionize, the trace detector detects the explosive particles. Basically, items or people are wiped or hand-vacuumed using a filter that is then inserted into the equipment for analysis of the sample. The technology is used on the theory that small explosive traces are usually left on the surface of items containing a bomb or on the skin or clothes of someone who has placed the bomb on their person or in their luggage.

X-ray systems can be used to show the shapes of items inside luggage so that a trained operator can look for what might perhaps be a bomb or components that could be used to make a bomb. Explosive materials, however, might have been molded into shapes that resemble common travel items, such as plastic bottles, making them difficult to detect with standard x-ray technology.

Consequently, a growing number of airports have started using bomb screening machines that employ computed tomography (CT), similar to the CAT scan x-ray technology used in the medical profession, to take more detailed x-rays of baggage.

A growing number of security end-users, meanwhile, are testing dual-energy x-ray technology, in which luggage is subjected to two different x-ray energy levels to calculate the atomic composition, density, and other characteristics of objects in the bag.

Another x-ray technology, backscatter technology, works similarly to the dual-energy x-ray. In addition to transmitting an x-ray beam through the luggage, it places a receiver on the same side of the bag. The x-rays are scattered back and then analyzed by a computer program. A series of algorithms makes computations based on density and atomic composition readings to determine whether a material is suspect.

Another detection method being tested is quadrupole resonance (QR) technology, based on magnetic resonance imaging used in hospitals. Elements in baggage are subjected to radio frequency energy instead of x-ray beams. Several airports worldwide are showing an interest in adopting this technology.

Dogs and pigs? Perhaps the most unlikely recent development among efforts to improve bomb detection is the decision of a former Israeli army dog trainer to train pigs to sniff out explosives. The trainer claims that pigs are easier to train than dogs because pigs learn faster. Nigel Edwards, chairman of the U.K.'s National Association of Security Dog Users (NASDU), is keeping an open mind about the ability of pigs to sniff out explosives. He says he will believe it when he sees it, but he is adamant that the sniffer dog is the most successful vapor detector around. "The sniffer dog is an incredible bomb detection machine, provided that the dog is properly rewarded, not overworked, and its handler is properly trained," says Edwards. "Even if the dog handler is having an off-day, it is still hard for the handler to miss anything suspicious because of the way the dog will react when it notices the suspicious item."

One investment bank recently established its own dog team because it became tired of having to keep evacuating staff due to a string of bomb hoaxes, says Edwards. "The bank asked for police assistance, but the police cannot attend every single call straight away, so the bank decided to set up its own explosives dog team to help the bank's security managers determine whether a suspect package is a bomb, without having to wait for the police and evacuate a site unnecessarily."

Portable systems. Several companies will soon make available portable x-ray systems that provide real-time computer images of x-rayed bags or packages, rather than the Polaroid film that police and army bomb squads have previously had to rely on when scanning suspicious baggage.

John Wyatt, technical director at security consultant SDS Group and a former bomb disposal officer and head of the U.K.'s High Risk Search Operations, explains the new system: "If there is an unattended bag at a train station, for example, a bomb squad officer will be able to go to the scene, place a small panel behind the bag and take the x-ray with the portable machine," he says. "The officer can often get a picture of a suspect bag within three minutes of arrival at a mainline station."

By contrast, he notes that with the film-based system, an officer has to decide on a pulse setting to use when taking the x-ray. A paper bag requires far fewer pulses than a rucksack or a leather briefcase, "so it is difficult to get the pulse setting right," he explains. When officers get it wrong, they are left with a picture that is under or over-exposed, forcing them to scan the bag again, a delay that could prove fatal.

Moreover, with the new technology, the x-ray machine is connected by cable to a laptop computer stored in a suitcase, and the x-ray is taken a fair distance away from the suspect bag. "It means you instantly get a digital picture of the x-ray on-screen and if the image is over or under-exposed, you can swiftly adjust the settings remotely from the PC without having to visit the suspect device again," explains Wyatt.

This new technology, which originates from Israel, is already being used by a few European police forces, but it does not come cheap. Costing around $100,000, the new PC-based machines are nearly ten times as expensive as the old Polaroid systems, which cost around $11,000.

In addition, New Scotland Yard's Anti-Terrorist Branch, along with British and American scientists, is working to develop a mobile scanner that is able to see from a distance the outline of a bomb or a weapon being concealed under clothing. Police officers would then intercept the suicide bomber, or evacuate an area, before the bomber strikes.

The device uses passive millimeter-wave scanning to pick up radiation from objects on a special camera using a waveband between infrared and microwave. On this wavelength, clothes emit almost no radiation and the scanner screen shows the human body as a dull, gray-colored shape, whereas hard objects such as plastic explosives are highlighted in a bright, white light. New Scotland Yard's Harrison says: "Development of the scanner is still at a fairly early stage, but the technology looks fairly promising."

Performance. As with any technology, the promises don't always match the performance in the field. Detective Superintendent Steven Harrison of the U.K.'s Anti-Terrorist Branch at New Scotland Yard says that the branch employs a team of officers to evaluate the effectiveness of bomb detection technology. "Our testers are called by suppliers on almost a daily basis who suggest that their latest system is the solution everyone has been waiting for," says Harrison. Then, when the systems are tested, "they produce too many false alarms."

The best trace detectors available can now detect explosive traces as small as 100 picograms in five seconds, Harrison notes. "The problem is that the trace detectors are just as likely to detect polish, floor cleaner, adhesives, and diesel and gasoline fumes, which causes the detectors to throw up too many false readings, especially in commercial buildings, where polish and floor cleaner are often used," he says. "Bomb detection systems are not yet highly tuned enough."

Wyatt notes that progress has been made, however. "Trace detection has improved enormously over the last few years and is now proving to be the most effective method for detecting explosives," he says, pointing out that trace detection machines from suppliers such as GE Ion Track and Smiths Detection have a very low false positive rate (around 1 percent) and a very short sample analysis time (five seconds). Moreover, they can detect a wide range of explosives.

But the effectiveness of a hand-held trace detector relies on the lifting off of trace material easily and the operator wiping the exact spot where the trace is located. Bearing this in mind, Wyatt believes that trace detection systems should be used alongside other bomb screening methods such as x-ray machines and sniffer dogs. Harrison agrees that using more than one type of technology is advisable.

Chris Smith, head of regional security for Europe at investment bank HSBC, says that calibration tools supplied with trace detectors can go a long way to ensuring that false positives are kept to a minimum. Security officers at HSBC sites use a GE Ion Track hand-held detector to scan parcels and vehicles for explosives. "Provided officers are properly trained in how to calibrate the equipment, which is not too difficult," Smith says, "there shouldn't be a problem with false alarms."

Operators, rather than the technology itself, are the key to how well the system works, agrees Fred De Domenico, head of security for European supermarket chain ASDA, owned by the Wal-Mart group. "In many cases, security officers just scan people with a cursory swipe of the detector." De Domenico, a former security consultant who has advised in-house corporate security teams on how to use bomb detection equipment, says that operators need to point firmly with a detector to apply sufficient pressure at areas where traces of explosives might lie.

Most leading manufacturers of hand-held detectors offer free training in how to use the detectors. Training can be provided at the manufacturer's offices, but HSBC's Smith invites GE Ion Track (which supplies hand-held trace detectors to HSBC) to the bank's sites so that his security staff can learn how to operate the detectors in their working environment. "We have a half-day training program for security officers to undergo," Smith says. "The manufacturer provides the technical training and then my security management team takes the officers through what to do if they come up with a positive reading."

HSBC's officers are taught what level of pressure to apply with the hand-held detector to a person and their belongings in order to give themselves every chance of picking up any particles of explosive substances. The detector needs to be applied firmly, but not so hard that it might upset the person being screened.

Training is also critical for operators of x-ray equipment. In addition to initial training, airports rely on an ongoing training program called Threat Image Protection (TIP) for screeners. TIP electronically projects images of possible threats, such as an explosive device, onto the x-ray monitor of the screener (which shows the image as if it were inside a bag being screened) to test the operator's ability to detect objects and to check that they aren't falling asleep on the job. But not everyone agrees on TIP's effectiveness. Wyatt says that TIP, which creates false alarms, can blunt operators' instincts, rather than sharpen them.

Wyatt also says that color x-ray machines cause more false positives. "With color x-ray systems, materials such as explosives are usually color-coded according to their atomic number and make-up and then identified by the color assigned to them," he says. "But not all organic material is explosives, so what tends to happen is that the operator keeps spotting orange items which turn out to be something innocent, rather than an explosive. When this keeps happening, the operator's enthusiasm for screening soon wanes."

London's Heathrow Airport uses a combination of trace detection and x-ray screening systems to scan passengers and their baggage for explosives and weapons. The British Airports Authority (BAA), which provides security at Heathrow, is currently testing walk-through explosive detection portals, which use trace detection technology.

On the inside, the detector works just like a hand-held or trace detector, but whereas the hand-held detector is designed to detect particles of explosives by being pressed against a person or item of luggage, the walk-through detector draws in particles by using jets of air, which blow the molecules off a person's skin, clothes, and luggage. The air is then drawn into the detector for chemical analysis. The passenger must stand in the portal for 10 seconds.

Manufacturers of the new walk-through detectors include Smiths Detection and GE Ion Track. GE's Entryscan3 walk-through detector recently passed the U.S. Transportation Security Administration (TSA) laboratory acceptance testing. And the TSA recently announced that four U.S. airports will participate in a 45-day pilot test of this technology using GE's Ion Track.

BAA is also currently testing an AXIS-3D x-ray machine at Heathrow Terminal One, which handles around 23 million passengers a year. Rapiscan and Image Scan Holdings, which jointly supplied the machine, say the system provides real-time three-dimensional (3-D) images of a passenger's baggage, giving security staff a better view of the contents.

Ian Hutcheson, director of security at BAA, has been impressed with the system so far. "Initial feedback from staff and passengers has been good, and staff are finding the equipment effective and easy­to-use," he says. By viewing baggage contents in 3-D, Hutcheson's security staff have found it easier to identify several objects grouped tightly together, which speeds up screening by reducing the need for manual searches. The system, which requires operators to wear special glasses, is also on trial at Budapest Airport in Hungary.

Business. The use of bomb detection technologies is still rare outside of airports. Businesses tend to balk at the prospect of subjecting staff and visitors to airport-style x-ray screening, fearing that it would overstretch security resources and disrupt the flow of people in and out of buildings. Some businesses, though, have introduced x-ray screening systems at building entrances since 9-11.

HSBC now scans baggage brought into work by staff, contractors, and visitors at some of the bank's offices in Europe. HSBC's Smith says employees have responded well to having their baggage screened. "The current climate is such that it is almost as if staff expect us to be doing this sort of thing," he notes. "We haven't had one person object to having their bag scanned."

They have, however, had to reassure staff that food and drink are not affected by x-rays. "We have had employees express concern that their salad leaves might be cooked by the x-rays," Smith says. As a result, signs and memos are used to reassure staff members that their packed lunches are safe to eat after security screening.

Michael Clarke, safety officer at the U.K.'s National Radiological Protection Board (NRPB), which advises Britain's airports on x-ray screening issues, says that airports have run into similar concerns. "We have had passengers worry about food being x-rayed, but they need not worry because the x-ray on these machines is essentially just like a bright light."

Port security. Europe's major sea ports are investing millions of euros in bomb and radiation detection equipment in an attempt to detect radioactive and nuclear material that could be used to make dirty bombs. For example, the Mediterranean's largest port, the Port of Marseille, which each month processes an average of more than 4,600 containers bound for the U.S. alone, will shortly begin using an HCV-Mobile x-ray inspection system, which supplier Smiths Detection claims can penetrate up to 270mm of steel. The Port of Marseille's head of security, Jean Charles-Geray, says staff will be able to deploy the inspection system anywhere within the port in less than 30 minutes and inspect up to 30 trucks an hour.

Dirty bombs. Another concern is the detection of radioactive material that might be used by terrorists in a so-called "dirty bomb," whose destructive force is from the contamination it spreads--or the fear of contamination--more than from the explosion itself. With the help of U.S. Customs' staff, Europe's busiest sea port, the Port of Rotterdam, has already begun testing four radiation detection monitors designed to scan complete trucks for dirty bomb material.

The monitors consist of two big poles that are attached to the ground. When trucks going to and from a shipping vessel stop between the two poles, the monitor sends a radiation reading to nearby customs officers, as well as the port's central customs control post. Rotterdam's customs officers, who have been taught by U.S. Customs' trainers how to use the monitors, study a computer screen that has an image of the radiation reading from inside the truck.

"If there is a high level of radiation, there will be a curve on the computer screen," says Renee Wesdorp, senior manager for port security. "Our officers have learned to recognize when there is a normal curve [suggesting normal levels of radiation] and when there is an abnormal curve. By checking the findings against the truck's inventory, they can then determine whether the contents of the truck and its containers require further inspection."

The port has found that even within a truck filled with broccoli, which emits normal levels of radiation, the detection monitor is able to detect anything concealed inside the broccoli which has a different density of radiation to the vegetable and could be dirty-bomb material. And the process is quick: "It only takes a couple of minutes or so," says Wesdorp.

If after examining all the information, customs officers still think something is suspicious, they take the truck out of the line to avoid delaying other vehicles. Officers then walk around the truck and take radiation readings from hand-held radiation detection monitors. If customs officers are then convinced that something dangerous is being hidden in the truck, they call in specialists from the environmental department who take over.

"Our customs officers don't just open the doors of the truck and look inside," says Wesdorp. "At this stage, the truck has to be moved and checked somewhere else, because we don't want to be opening a potentially dangerous vehicle in an area densely populated."

The port will purchase between 30 and 40 detection monitors to cover all its docks if the trial is successful. The final results of the trial are not due until later this year, but the early signs are encouraging, says Wesdorp.

The detectors may also help ports detect human smuggling, says Colin Braziel, managing director of Griffin IT Management Ltd and a member of the U.K.'s Association of Security Consultants (ASC). Braziel, who is currently advising several ports on how to comply with the recent directive on security from the International Maritime Organization, says the technology can be adapted to detect carbon dioxide inside trucks, "which would enable customs officers to scan complete trucks for people being smuggled into a country."

Other applications. European governments are also preparing for the worst by investing in systems for detecting evidence of a chemical, biological, radiological, or nuclear (CBRN) attack. The German government, for example, has provided the country's 16 states with a total of 367 CBRN detection vehicles, which would be called into action in the event of an attack. Each vehicle contains a mobile mass spectrometer, which the government says can detect chemical agents in less than 45 seconds and biological agents in less than four minutes. The detection vehicles have yet to be tested in an emergency.

The U.K. government has begun rolling out radiation detection equipment to all National Health Service (NHS) hospital emergency rooms and ambulance crews so that they can detect fallout from dirty bombs and determine whether patients have been exposed to radiation. The hand-held pager-sized detectors cost around $1,500 each and, like the detection vehicles in use in Germany, use mobile mass spectrometer technology to detect chemical, biological or nuclear agents in the air.

Anybody who owns a cell phone could soon be carrying their own dirty bomb detector. Cell phone company Nokia has expressed an interest in a technology currently being developed by scientists from several countries which could see cell phones fitted with sensors to detect the presence of nuclear, biological, or chemical traces in the atmosphere. The phone would alert a command center and simultaneously warn the user to seek medical attention. Scientists are hopeful that the sensors could detect anything from anthrax to sarin gas and could cut casualty rates by up to 70 percent.

But the U.K. government has expressed concern that the sensors--which scientists expect to add $10 to the cost of a mobile phone--could cause constant panic by falsely alarming members of the public into thinking they have been exposed to a dirty bomb. Scientists working on the technology claim that they will be able to quickly tell when an alert is false and will inform users, but that may be too late to avert panic, says the British government.

Radiation detectors aimed at corporate offices are also being introduced. International metals group Corus has just launched what it describes as Europe's first lightweight, compact radiation detection system. The system, which Corus has designed to fit inside mail rooms and building entrances, costs $17,000, but Steven Beamon, director at security consultancy International Risk Services, questions whether businesses would be well served by spending large chunks of their security budgets on CBRN detection equipment.

Beamon, who spent the last three years of his 32-year career in the Metropolitan Police helping to develop plans for dealing with a CBRN attack in London, considers it unlikely that a terrorist group will spend a lot of time, effort, and money in producing a chemical or biological weapon simply to target one organization. He suggests that security directors "would be better off spending their employer's money on installing barriers and other measures to ensure that no one can enter the building unchecked."

Beamon further notes that false alarms would cause unnecessary evacuations of company premises and public areas, disrupting operations and alarming the public.

The bottom line, as with many security issues, is that bomb-detection technology can be a useful weapon in a security manager's armory, depending on the organization's risk profile, but it is no panacea. Other security measures, such as perimeter protection, CCTV, access control and employee vetting, remain as crucial as ever to an organization's overall counterterrorism strategy.

Lawrence Mark Cohen is a freelance writer living in the U.K.



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