LEWISTON  — Officials say a flash fire that injured five people in a hot air balloon at a Maine balloon festival was caused by a faulty valve on a propane tank.

Maine Public Safety spokesman Steve McCausland tells WMTW-TV the valve on the propane tank allowed gas to escape during Saturday’s Great Falls Balloon Festival in Lewiston. The gas was ignited by a pilot light.

The balloon’s pilot, Andre Boucher of Derry, N.H., suffered second degree burns. He was released from the hospital Monday.

Four other people suffered lesser injuries.