A bomb squad arrived within five minutes and determined there were no explosive materials in the watch, Nelson said. The checkpoint was closed while officers secured the area.

McGann was taken to Santa Rita Jail in Dublin where he was charged with possessing materials to make an explosive device, sheriff's officials said. He was still in custody Friday night and could not be reached for comment.

McGann told Transportation Security Administration officers that he's an artist and the watch is art, Nelson said.

While no actual explosives were found, McGann was carrying potentially dangerous materials and appeared to have made alterations to his boots, which were unusually large and stuffed with layers of insoles, Nelson said.