WASHINGTON -- When covert agents test how well airport security screeners find homemade bombs, they pack a detonator, timer and battery inside a cluttered toilet kit, stuff it into a suitcase and carry it through a checkpoint.
Agents also hide fake sheet explosives in briefcase linings. They stash watch timers inside hollowed-out books. They cram detonators in back braces and smear plastic explosives on shoelaces.
The Transportation Security Administration's special operations division devised the testing to raise the stakes for airport screeners and test whether they can spot bomb parts hidden as a terrorist might try to get them on an airplane, according to a classified TSA report obtained by USA TODAY.
The testing in the past year is far harder than it was before and shortly after the TSA took over airport security in 2002, agency spokeswoman Ellen Howe said. In earlier tests, covert agents would put a gun or a large assembled bomb in an otherwise-empty briefcase, she said.
Howe said the increased difficulty explains why screeners at Los Angeles and Chicago O'Hare airports failed to find more than 60% of fake explosives that TSA agents tried to get through checkpoints last year.
The failure rates -- about 75% at Los Angeles and 60% at O'Hare -- are higher than some tests of screeners a few years ago and equivalent to other previous tests.
"We want to have higher failure rates because it shows that we're raising the bar and the tests are harder," Howe said.
Using a basketball analogy, she added, "You might score more points against a high school team, but your skills are going to be improved if you're playing against an NBA team."
Aviation-security consultant Rich Roth worries that high failure rates may encourage terrorists to try to bring bombs on airplanes. "The terrorist will think he's got a very small chance of getting caught," Roth said.
TSA chief Kip Hawley has intensified efforts to stop terrorists from carrying bomb parts on a plane where they could be assembled. Shortly after he took office in 2005, the nation's 43,000 screeners began getting an extra hour a week of training to find bombs and components, Howe said.
This year, the TSA for the first time began running covert tests every day at every checkpoint at every airport. That began partly in response to the classified TSA report showing that screeners at San Francisco International Airport were tested several times a day and found about 80% of the fake bombs.
Constant testing makes screeners "more suspicious as well as more capable of recognizing (bomb) components," the report said. The report does not explain the high failure rates but said O'Hare's checkpoints were too congested and too wide for supervisors to monitor screeners.
At San Francisco, "everybody realizes they are under scrutiny, being watched and tested constantly," said Gerald Berry, president of Covenant Aviation Security, which hires and manages the San Francisco screeners. San Francisco is one of eight airports, most of them small, where screeners work for a private company instead of the TSA. The idea for constant testing came from Ed Gomez, TSA security director at San Francisco, Berry said. The tests often involve an undercover person putting a bag with a fake bomb on an X-ray machine belt, he said.