Hill declined to elaborate on their success, citing security concerns.
Melendez said no timetable has been set for fixing the problems and resuming the installations.
"It wasn't the hardware," Melendez said.
Hill said making puffers work seamlessly with other screening equipment has proved harder than expected. Every airport is different, which makes it difficult to standardize the installations.
''Integrating it into an existing checkpoint that doesn't stop and runs 20 hours a day requires coordination with not only TSA but also with the airport, typically more than one airline, architects and engineers. It's actually a pretty complicated process, and every deployment is different," Hill said.
At the bottom, the value of puffers is difficult to gauge. They are meant to prevent terrorists from smuggling explosives onboard jetliners, a goal whose success is hard to measure. What's more, not every passenger is screened, unlike with metal detectors, which everyone must pass through.
"If you've got to pick on one, you've got to pick on all," said Anthony Velazquez, a muscular New Yorker with tattoos on his biceps, a pencil-thin beard that follows his jawline, and a gold chain and cross dangling from his neck.
"Looks are deceiving, especially from a big city, where I come from. You've got mixed ethic groups. One could look like a criminal [to a TSA agent] and not the other," said Velazquez, who calls himself a patriot who loves his country and government.
Flieger, who flies every week on business but has only been through a puffer once since they were rolled out two years ago, called them a waste.
"It's a waste of money that could have been spent on [security for] ports and container shipping," he said.
Five trace portals machines are operational at SLC; one is at the International Terminal checkpoint, with two each at the Terminal One and Terminal Two security checkpoints.
Beginning as early as this week, selected passengers at Sacramento International Airport checkpoints will get a breezy once-over from the newest device in the federal government's anti-terrorism...
Tom Rice, Transportation Security Administration director in Columbus, said Port Columbus could receive the machine shortly.
Sky Harbor International Airport is prepared to spend up to $15 million on surveillance equipment designed to detect terrorists or other criminals lurking around the airport's edges.