At approximately 9:20 a.m. on December 1, 2010, Employee #1, #2 and #3 were working on the barge of an oilrig (Rig Number 1). They were removing a Christmas tree flange, an assembly of valves, spools, and fittings used to control the flow of oil or gas out of the well, with a cutting torch. As Employee #2 and #3 assisted Employee #1, he cut the last bolt of the flange when gas ejected from the control device. The released gas immediately ignited, forming a fireball.