The Transportation Security Administration has spent more than $160 million on airport body scanners at U.S. airports since 2008, a startling amount to spend on a technology that recently failed to detect fake explosives and weapons in 96 percent of tests conducted by undercover TSA agents.

Of the $160 million spent on body scanners, $120 was spent on millimeter scanner machines manufactured by L-3 Communications and still used in airports around the nation, reported Politico. The rest of the money was spent on the agency's so-called "naked X-ray scanners," which were removed from airports in May 2013 after passengers became concerned about privacy violations and health risks.

The millimeter-wave machines still used in airports have cost more than $150,000 a piece on average since the agency purchased the first 45 scanners in 2008, according to numbers the TSA recently gave lawmakers.

The acting TSA administrator was reassigned in June after TSA agents and devices failed to detect fake weapons and explosives in 67 out of 70 covert tests carried out by a special Department of Homeland Security team, as Fox News reported.

Texas Republican Mike McCaul, chairman of the House Homeland Security Committee, confirmed that the L-3 scanners were largely to blame, saying, "the technology failure was a big part of the problem," adding that the manufacturer guarantees an accuracy rate far below 100 percent.

The TSA and L-3 Communications said they believe the security flaws can be fixed with software patches and training improvements, but many lawmakers and security experts remain doubtful.

Senate Homeland Security Chairman Ron Johnson, R-Wis., said the machines are such a failure that people should have to walk through additional metal detectors after going through the body scanners.

"These things weren't even catching metal," Johnson told Politico. "If you really want to keep using those, and I'm not saying we shouldn't, at a minimum we should put a metal detector on the other side," he added. "Why not go through two? You've just gotta use common sense."

Rather than create a magnetic field to detect metallic objects, the body scanners project radio frequency energy over a person's body to detect unusual items, according to Newsmax.

Rep. Bennie Thompson of Mississippi, the top Democrat on the House Homeland Security Committee, said he is "troubled about their capability to detect and prevent dangerous materials from passing through security checkpoints."

Steve Bucci, a security expert who was a former top Pentagon official and Army Special Forces officer before becoming a policy director at the Heritage Foundation, told Politico that the TSA should first try to patch the software to make the machines more effective, but added that "there is not a pure technological fix that is going to give us complete security and complete convenience."

Bucci suggested that many of the security lapses could stem from inadequate training or incompetent TSA agents.

"Most of them are really good, very polite, very efficient, very professional," he said. "But there are a lot of them that aren't the sharpest knives in the drawer."

The TSA released a statement reiterating its intent "to improve screening effectiveness, including new training for all TSA officers, improvements in alarm resolution procedures, and, in partnership with private sector partners, a range of measures to increase detection standards of our screening equipment."