(Agencies)
Updated: 2007-11-15 09:13

Washington -- Government investigators smuggled liquid explosives and detonators past airport security, exposing a dangerous hole in the United States' ability to keep these forbidden items off of airplanes, according to a report made public Wednesday.

Workers X-ray passengers belongings, including a pair of shoes, at Washington Dulles International Airport in this 2006 file photo. [Agencies]

The investigators learned about the components to make an improvised explosive device on the Internet and purchased the parts at local stores, according to the report by the Government Accountability Office. These covert tests were conducted at Transportation Security Administration (TSA) checkpoints at 19 airports in March, May and June of this year.

In August 2006, the TSA changed its screening policies after officials foiled a plot to use liquid explosives to blow up commercial airlines headed toward the US.

But the investigators only tested one of TSA's 19 layers of security, said TSA spokeswoman Ellen Howe.

"While people think about us in terms of the checkpoints and they see us as the checkpoints, there's a lot more layers of security," she said. In addition to the checkpoints, TSA uses different technologies and has officials who check the validity of documents and observe people's behaviors throughout the airport. "Just because somebody gets through one layer doesn't mean they're going to get through all of the layers."

The report released Wednesday is a version of a classified report with sensitive information blacked out.

In prepared testimony for a congressional hearing Thursday, TSA Administrator Kip Hawley said, "Relying solely on security at the checkpoint or focusing all of our resources to defeat one threat is counterproductive and detracts from our overall mission."