A 24-year-old man from Bangor is facing charges after police say a loaded gun he was carrying went off on a city bus Wednesday afternoon.Police say Jason Robinson was showing the gun to someone else when it accidentally fired, there were about 20 people on the bus, but no one was hurt.Police say Robinson got off that bus and got on another one, which was stopped by police in Orono.Robinson was arrested without incident. The bus with the bullet hole is undergoing repairs.B.A.T. Superintendent Joe McNeil says there could be several hundred dollars damage because a panel of the bus needs to be replaced. “I think it’s a very very isolated incident most people are good and generous and this obviously happened and happened in our presence, but I’ve been here a number of years and we’ve never had anything to this type of incident,” Said McNeil. “He was stuffing it in his jacket with his finger on the trigger and the gun just went off.,” Said Christopher Stone, who was on the bus. “It scared us all at the moment I thought he fired at me because of the way he was looking at me and then after the hairline of a second I realized he had shot out the side of the bus.”Robinson is charged with reckless conduct with a firearm and carrying a concealed weapon, he remains at the Penobscot County Jail.