A HOIST DRUM BEARING OVERHEATED AND BLEW APART IGNITING GREASE THAT IS USED TO LUBRICATE THE BEARINGS & HOIST GEARING MACHINE WAS IN OPERATION. 2-150 LB DRY CHEMICAL & 12-20 LB DRY CHEMICAL EXT. WERE USED TO PUT OUT THE FIRE. FIRE DEPT. WAS CALLED BUT NOT NEEDED. DAMAGE WAS LIMITED TO THE BEARING THAT FAILED. FIRE WAS PUT OUT IN 35-40 MINUTES.