On the way to her flight, Gerry Belton unshouldered her white tote bag with the blue straps and dropped it onto the security X-ray machine at Hobby Airport.
As she passed through the silent metal detector archway, her bag reappeared from the X-ray scan with no apparent problems. But the security guard stopped her as she retrieved it. While the guard said she wanted to inspect the bag, she never even looked inside. Instead, she carefully wiped its handles with a circular white Oxy-Pad-like cloth and put the pad in a bread-box-size machine.
Thirty seconds later Belton had her bag back and was on the way to her gate. She says she's a regular flier who gets this hocus-pocus treatment about every fourth flight but doesn't mind the brief delay.
"Nah, I'm glad they do it," she says, although Belton, like most air passengers, doesn't know how the extra security check really works.
As the holiday crush of travelers approaches, many more bags and purses will get this same rubdown, all done in the name of aviation safety.
The carry-on gear of selected travelers has to pass muster on what could be called the smell test. Credit -- or blame -- it on the 1996 explosion of TWA Flight 800, which killed 230 passengers and crew.
Investigators feared that a bomb had caused that crash, sending scientists back to the labs to perfect new ways of detecting explosives being carried aboard commercial aircraft.
By 1997 Congress had allocated $144 million to the Federal Aviation Agency for long-term research, purchase and installation of bomb detection equipment at airports. The agency made an initial $12.2 million buy of supersensitive "sniffing" devices to be located at the nation's busiest terminals.
In 1998, 327 of the machines were installed, with 96 more added this year, the FAA reports. Houston aviation officials refuse to say when the devices began appearing locally or how many have been installed -- or anything else about them.
The three companies that won the government contracts are Massachusetts-based Thermedics Detection Inc. and Ion Track Instruments, and Barringer Instruments Inc. of New Jersey.
While the technology remains classified, the process is relatively simple. Airport inspectors wipe or vacuum the outer surface of selected bags and have the wipe pads or vacuum filters analyzed -- sniffed -- for several types of minute particles of known explosive materials.
Authorities in detection and security-related fields have mixed views on the electronic advances.
"The question is, does [the technology] in fact find what you're looking for," says Richard Lanza, a professor at the Massachusetts Institute of Technology. "That's always been the critique of these things."
Lanza says sometimes explosives detection equipment is too sensitive. He says that was the problem Air Canada encountered. In a country rich with mining, such as Canada, the machines would find explosive residue not necessarily linked to a bomb.
"[Gunpowder] takes forever to get off your hands," reasons Raymond Ellis, a University of Houston professor specializing in security. Furthermore, he isn't certain that the machinery would detect more expertly crafted plastic explosives, he says.
But, "certainly, it would be effective if you've been making a pipe bomb and you've been working with powder."
Checks of all carry-ons are considered too time-consuming for already crowded airport terminals. But the samplings raise questions about the effectiveness of the process. Airport authorities say the checks are random, that there is no profiling used to pick out who is screened. A security manager at Palm Beach International Airport told the news media that about one third of all passengers are checked, a ratio that coincides with Hobby passenger Belton's estimate.
Detectors can be equipped to screen for drugs as well as weapons, although aviation authorities insist that the airport equipment is set up to look for only traces of explosives rather than drugs.
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If it seems high-tech, next-generation equipment may wipe out the need for the pads. Ion Track is building a sensing portal which could detect explosive residue by the change it causes in body heat, according to Penn State University designers.
Thermedics Detection Inc. has a gizmo that handles eight to ten passengers per minute and detects explosives, drugs and metal. It features wands that brush against the passengers as they walk through, collecting residue samples that are analyzed almost instantly.
However, industry officials say most of these sophisticated systems are too large, ineffective or costly to go into regular airport service. Barringer president Ken Wood told the trade magazine Military & Aerospace Electronics that technology is being developed that could replace the current equipment with devices that could detect explosives by "sniffing" that common staple of terminal traffic: the basic boarding pass.
E-mail Seth Landau at firstname.lastname@example.org.