Cell phone camera video obtained by CBS News recorded workers over the last several days entering a restricted area of New York's JFK airport. The employees scan a security card, enter a pin number and walk through the turnstile.
Their identities are not verified and their bags are not checked.
Florida Senator Bill Nelson says it shows an obvious vulnerability at the nation's airports.
"I'm horrified, but I'm not surprised," Nelson said. "I think one of the main threats is employees of the airport getting on carrying contraband, possibly weapons. There you have the potential for disaster."
It's recently happened overseas. Last year, a Russian jetliner crashed in Egypt after someone with access to the plane smuggled a soda can bomb on board. And a bomb that blew a hole in a plane in Somalia was carried around security in a laptop.
In the U.S., airport workers are given key cards after they complete a background check and their names are run through criminal and terror databases.
But a 2015 report by the Department of Homeland Security inspector general's office found "TSA did not identify 73 individuals with terrorism-related category codes."
Some workers call the badges the "key to the city" -- because once you have one, employee screening is spotty at best.
It's what allowed a Delta employee in 2014 to smuggle more than 100 guns through airport security in Atlanta and hand them off to a passenger headed to New York.
"That person went through a background check, but a year after they got hired they could be doing some nefarious acts. So there's not a continuing screening process, so it's not sufficient," said Marshall McClain, co-founder of the American Alliance of Airport Police Officers.
TSA says it screens 17 million airport workers and conducts more than 3,000 tests to reduce the insider threat. It is now working closer with law enforcement agencies to share information across all terror databases.