ATLANTIC CITY, N.J. — Eight years after the Sept. 11 attacks, the front line in America's war on terrorism runs through a little-known federal laboratory where engineer Nelson Carey holds what appears to be a bratwurst in a bun.
"This is a Semtex sausage," said Carey, as he pinched the pink plastic explosive long favored by terrorist groups.
On his table lies a green Teletubby doll stuffed with C-4 military explosives, a leather sandal with a high-explosive shoe insert, an Entenmann's cake covered in an explosive compound that looks like white frosting, and other deadly devices Carey and his colleagues have built. None have detonators, so they are safe.
"We let our imaginations go wild," Carey said. "The types of improvised explosive devices are endless."
So are possible solutions, at least in theory. That's where the Transportation Security Laboratory comes in. Scientists here dream up ways an enemy might slip a weapon or a bomb onto a plane, and then try to build defenses to detect or counter the danger.
The work is part cutting-edge science, part Maxwell Smart.
Staffers have experimented by exploding more than 200 bombs on junked jetliners. They also have filled a warehouse with nearly 10,000 lost or abandoned suitcases and other packed luggage.
"We build bombs in them" and run them through airport-style screening machines, said Susan Hallowell, the lab director. If a bomb escapes detection, technicians try to figure out why and how to catch it next time. "We call it the art of bagology."
Most important, the lab evaluates and certifies all equipment purchased from outside vendors to search, sniff or scan passengers and their luggage at some 450 U.S. airports.
Dr. Colin Drury, distinguished professor emeritus of engineering at the State University of New York at Buffalo, calls the lab "one of the best in the world for the kind of work they do."
"They think broadly and have new ideas, and maybe 90% don't work," he said. "But that's OK, as long as 10% do."
About 125 chemists, physicists, engineers and others work in the lab's low-slung buildings on a wooded campus behind high fences and armed guards at the edge of the Atlantic City International Airport.
Inside is an odd mix of standard cubicles and blast-resistant rooms with thick steel doors and three reinforced walls. If an accident occurs, the design is supposed to channel the explosion to the fourth wall, which faces outside.
It's a work environment filled with painful reminders of how terrorism has changed the world.
Hallowell, 56, joined the lab as an analytic chemist when it first opened after the 1988 terrorist bombing of Pan Am Flight 103 over Lockerbie, Scotland. The lab still keeps a mock-up of the Semtex-filled boombox that brought the jet down, killing 270 people.
Hallowell was named director shortly after the Sept. 11, 2001, attacks, which turned the backwater lab into a small but crucial cog in what became the Homeland Security apparatus. Its budget has seesawed, but now is about $45 million a year.
Like Q in the James Bond films, Hallowell clearly enjoys the unusual tools -- and the dark humor -- of her profession.
Showing a reporter around, she stops to take a woman's shiny black pump off a shelf. It hides an inert explosive in the heel.
"I've always liked this shoe," she said. "It's my size."
Much of the lab's work focuses on far-off technology.
In one room, chemist Inho Cho has put liquid explosive in a small purple bottle of NutriPals, a nutrition drink for children. It sits in a blast-proof, see-through box while he tries to determine how sensitive a screening portal must be to identify vapors that leak from the bottle.
"Maybe five years from now, the sensors will be sensitive enough," he said.
In another room, research physicist Rob Kleug uses medical technology to take what looks to be a brain scan of a peanut M&M. He measures the candy's mass density and effective atomic number, and compares the data to that of known explosives.
"We're still looking for practical applications," he said.
Nearby, physicist Jeff Barber aims very high-frequency radio waves at an explosive compound. He probes the interaction between molecules in an effort to produce a unique visual signature that can be compared with other materials.
"This is the final frontier," he said, showing a colorful graph on his computer monitor that represents TNT powder. "It's still in the experimental stage."
The lab's efforts to detect hidden threats increasingly competes with the need to protect the privacy of innocent travelers. As a result, the lab is caught in the latest controversy involving the Transportation Security Agency, the lab's chief customer.
Janet Napolitano, secretary of Homeland Security, announced this month that the TSA will deploy 150 backscatter imaging machines at checkpoints in major airports, including Los Angeles International Airport, adding to 46 tested in a pilot project.