Government investigators were able to bring materials needed to construct bombs through airport security at 21 different U.S. airports, according to NBC Nightly News.

Sources who spoke to NBC on condition of anonymity, because the Government Accountability Office investigation is classified, said that not once did Transportation Security Administration screeners catch the bomb components in carry-on luggage, even when the investigators deliberately went through secondary screening.

“Detecting explosive materials and IEDs at the checkpoint is TSA’s top priority,” said a statement TSA provided to NBC Nightly News.

Former New Jersey governor Tom Kean, a member of the 9/11 Commission, told NBC: “I’m dismayed and, yes, to a degree, it does surprise me. Because I thought the Department of Homeland Security was making some progress on this, and evidently they’re not.”

I’m not a bit surprised. It’s precisely what I expected.

TSA said that it is working on training screeners to “identify possible explosive materials and IED components.” And it’s clear they need the training. Back in October, a TSA screener mistook a cookie and a child’s toy for IED components, snarling the San Diego, Calif., airport for two hours.