Two loaded firearms were discovered at Hartsfield-Jackson International Airport checkpoints Thursday morning, the TSA announced.

Additionally, two inert grenades were found in a passenger’s checked bag, Transportation Security Administration spokesman Mark Howell said.

Howell said a loaded .22-caliber derringer was discovered in a passenger’s carry-on bag about 6:40 a.m. About 20 minutes later, a .380-caliber loaded Ruger was found in another passenger carry-on bag and around 10:30, two inert grenades were found in another bag during screening.

Authorities arrested Ruger owner Matthew Brott after it was discovered his Georgia permit had an expired. He was taken to the Clayton County jail, said Sgt. Greg Lyon with Atlanta Police, which has jurisdiction over the airport.

Brott said he forgot the handgun was in his bag, Lyon said.

Derringer-owner Robert Harwell had a valid permit and was not arrested, Lyon said. Harwell also said he forgot the revolver was in his bag, Lyon said. Police did not respond when TSA discovered the false grenades, Lyon said.

Howell said passengers can transport guns in checked baggage but not on carry-ons.

“Passengers are responsible for the contents of bags they bring to the checkpoint,” Howell said. “Our advice is to look through bags thoroughly before coming to the airport to make sure there are no illegal or prohibited items.”

In addition to potential criminal charges, passengers who bring firearms to a checkpoint face civil penalties from TSA.