While workers were circulating well gas through the choke with the annular closed SIDPP (Shut In Drill Pipe Pressure @ 350 kpa [51 psi]), it was noticed that the fire in a pail, positioned under the degasser line, had extinguished. On the Rig Manager’s order, the rig stopped pumping, and the HCR valve was closed, shutting in the well. The Rig Manager then instructed a worker to go to the end of the degasser line at the flare pit and to re-ignite the contents of the pail. The worker attempted to light the contents of the pail with his personal cigarette lighter, and a flash fire resulted from the spark of his lighter, igniting the methane gas venting from the opening at the end of the degasser line. As a result, the worker was seriously injured, with second degree burns to his hands and face.