DURING A PANIC STOP, PASSENGER'S SIDE, REAR SEAT BELTS FAILED, AND THE PASSENGER WAS THRUST INTO THE BACK OF THE FRONT SEAT,. FURTHER INSPECTION REVEALED THE RETRACTOR CASING HAD FALLEN APART. OLDSMOBILE ADVISED ME SEAT BELT MAINTENANCE WAS MY RESPONSIBILTY. I HAVE SINCE LEARNED OF TSB 91C09 AND 91C09A, DATED 11/92 CONCERNING THIS VEHICLE ( I HAVE NO SPECIFICS). INSPECTION OF THE OTHER BELTS SHOW THEY ARE FAILING AS WELL. THE OWNERS MANUAL HAS NO INSTRUCTIONS ON MAINTENANCE/INSPECTION SCHEDULES, OR USER-SERVICEABLE PARTS EITHER. *AK