The government is scrapping a post-Sept. 11 airport screening program because the machines did not operate as well as intended and cost too much to maintain.
The so-called "puffer" machines were deployed to airports in 2004 to screen randomly selected passengers for bombs after they cleared the standard metal detectors. The machines take 17 seconds to check a passenger and can analyze particles as small as one-billionth of a gram.
But they would also break down when exposed to dirt or humidity, the Transportation Security Administration said in a statement released Thursday. Since 2005, maintenance of the machines cost taxpayers more than $6 million.
Ninety-four of the machines were deployed to 37 airports in 2004, and the government planned to deploy 113 more machines at airports. But because of some of the performance issues, the government decided not to continue the rollout, and the rest stayed in storage.
The machines cost about $160,000 each and were made by General Electric and Smiths Detection.
"They got frustrated with the technology and moved on to something else — I think is the short story," Smiths Detection vice president Brook Miller said of TSA.
Miller said the puffers had maintenance issues early on because they puff air and then suck it into the system to analyze it. "It just wasn't to be in the airport environment," he said. Puffers are still used at facilities with less human traffic to detect drugs, he said.
Smiths Detection, which is based in England, is one of the manufacturers of the full-body imaging machines that will replace the puffers.
The full-body imaging machines, already used at some U.S. airports, have raised some privacy concerns. In their search for bombs, guns, knives and other potential weapons, the machines create images of passengers through their clothing.
The TSA has removed 60 puffer machines from airports since last summer. TSA spokeswoman Kristin Lee said the machines are being removed on a case-by-case basis, and their removal does not create any security gaps.
Officials from General Electric could not be reached for comment.
The government has spent $42.3 billion on aviation security since the Sept. 11, 2001, terror attacks, according to TSA.