At Tuesday's hearing, the chairman of the Subcommittee on Transportation Security, John Katko, asked US transportation authorities whether it was true that airports did not check the criminal history of their workers after they had passed initial background checks.
"That is correct from my knowledge," Perdue said, as quoted by the CNN.
During the hearing, members of the Subcommittee criticized existing loopholes in airport security and discussed ways to reduce potential insider threats posed by employees. The head of the Transportation Security Administration Mark Hatfield, however, said that physical screening of all airport employees was "cost prohibitive."
The hearing came after a gun smuggling scheme in Atlanta airport was revealed in December last year. A Delta Air Lines employee used his security clearance to help a former Delta worker to bring firearms in his hand luggage. The two men managed to smuggle 129 handguns and two assault rifles onto planes between May and December 2014.