EE WAS REMOVING FILL PLUG FROM DIFFERENTIAL OF #05-30 HAUL TRUCK. AS PLUG WAS REMOVED, PRESSURE BLEW HOT OIL ONTO EE'S FACE, NECK CHEST AREA, RIGHT ARM & HAND, & LEFT FOREARM. EE REC'D 2ND & 3 RD DEGREE BURNS TO ABOVE MENTIONED AREAS (APPROX 15% OF BODY). EE WAS TRANSFERRED BY AMBULANCE TO PARKLAND HOSPITAL IN FARMINGTON, WAS LATER TRANSFERRED TO ST JOHNS HOSPITAL IN ST LOUIS.