WORKING ON WATER SUPPLY PIPPING TO GRINDING AID WATER TANK. FIVE FT. LADDER AGAINST WATER WATER TANK. EE ON LADDER WORKING ON FLOAT IN TOP TANK,WHEN HIS FOOT SLIPPED ON RUNG. EE GRABBED PIPE T O STOP FALL, BUT BANGED AGAINST SIDE OF TANK AND HIS PIPE WRENCHES WITH LEFT SIDE OF BODY.