EE WAS REPAIRING THE CHAIN DRIVE CASING OF THE GRADER. HE HAD FINISHED WELDING THE OUTSIDE OF THE CASE AND WAS PREPARING THE INSIDE FOR WELDING. HE USED STARTING FLUID TO CLEAN THE INSIDE ALLO WING 20 MIN FOR THE FUMES TO CLEAR AND ALSO USING COMPRESSED AIR TO BLOW OUT CASE. HE STRUCK AN ARC AND IGNITED FUMES CAUSING BURNS TO HIS ARM 2 ND DEGREE.