INJURED WAS REMOVING HYDRAULIC LINES FROM 988-B LOADER. HANDS WERE COVERED WITH OIL AND GREASE WHILE USING A KNIFE TO CUT OLD TIE WRAPS FROM BRACKETS HOLDING LINES. ATTEMPTING TO REMOVE LAST T IE WRAP, IT BROKE UNEXPECTEDLY, LETTING KNIFE STRIKIE RIGHT HAND, IN THUMB AREA, CAUSING LACERATION.