A bozo carrying a loaded sawed-off shotgun in his gym bag accidentally blasted his own leg while waiting to board a bus Saturday morning at the Port Authority terminal.

Joseph Riddick, 35, of Worcester, Mass., was standing on line when his foot brushed the bag and the shotgun went off. He fell to the ground as other passengers scattered.

Rookie PA cops Faye Stephans and Vijay Seeteram administered first aid and put Riddick in an ambulance to Bellevue Hospital. He now faces weapon-possession charges, a police source said.

Riddick’s Facebook page shows him shirtless with a tattoo of a sawed-off shotgun on his chest.