Imagining new threats -- and countering them

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 is 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 9/11 attacks, which turned the backwater lab into a small but crucial cog in what became a DHS apparatus. Its budget has seesawed, but now is about $45 million a year.

As was the case with 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.”

Drogin writes that 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