Local Company Steps Up Security

At airport security checkpoints, it doesn't take much to stop a terrorist anymore.

To be exact, it takes one picogram -- a trillionth of a gram, less than the weight of a human fingerprint. Security workers swab suitcases for traces of explosive so small, if your cab driver had been making bombs, your luggage could set off alarms.

"What they're looking for is microscopic traces of explosive that have been transferred," said Dan Dussault, product manager for Waltham-based Thermo Electron. "A fingerprint, for example, is a microgram of material. You're looking for material that is much, much less than a fingerprint."

Thermo Electron was the first to develop high-sensitivity explosives detection machines for use in the field in 1989. Its latest model, the Egis Defender, is the size of a desktop fax machine. It is manufactured in Thermo's Franklin plant.

Dan dussault, product line manager at Thermo Electron Corp. production facility in Franklin, talks about the company's gas chromagraph machine. (Mike Springer photo)

An earlier model, the Egis 2, was so sensitive it led investigators to first suspect a bombing in the explosion of TWA Flight 800 in 1996. Traces of explosive identified on the wreckage turned out to be left over from an exercise for bomb-sniffing dogs, held three weeks before the crash, however.

Sensitivity is important to process packages and people quickly, said homeland security consultant W. David Stephenson. "If it's not sensitive enough to smell the contaminants without an invasive process, then it slows things down," he said.

The Defender is slightly less sensitive than its predecessors, but it detects a wider range of chemicals, like explosives made from household ingredients used in the London bus bombing last summer, and carried by shoe bomber Richard Reid in 2001.

"It's a game of cat and mouse," said Dussault. The ability to detect more than one kind of chemical gives security equipment makers a head start, he said. "We have much more head room now to expand."

Older machines were also more susceptible to false alarms. 1990s models sometimes confused components in women's make-up with explosives. Musk-scented men's aftershave, popular in the 1970s, continued to set off alarms in the 1980s, Dussault said -- and not just with women in bars.

Occasionally, false positives do still occur in 2006.

"We often recommend that golfers take time to clean their clubs and cleats," said Ann Davis, Northeast spokeswoman for the Transportation Security Administration. Ammonium nitrate in golf course fertilizers is also a component in some explosives, she explained.

Ultimately, anyone who sets off an alarm is going to be "subject to additional screening procedures," such as a physical search of their baggage, Davis said.

But not to worry. "Additional screening procedures are not too invasive," she said. "We train our screeners to approach those procedures with professionalism and sensitivity."