EXPLORER WAS IMPACTED BY SECOND VEHICLE ON LEFT REAR SIDE, CAUSING EXTENSIVE DAMAGE TO EXPLORER AND CAUSING IT TO SPIN. LEFT SIDE OF SEAT BACK BROKE (I.E., VERTICAL METAL ARM BROKE, I.E., METAL SEPARATED), ALLOWING SEAT BACK TO COLLAPSE BACKWARD. THE TWO 11-YEAR OLD GIRLS SEAT-BELTED IN THIS SEAT WERE EJECTED REARWARD OUT FROM UNDER THEIR SEAT BELTS, EXITING REAR WINDOW(S). ONE WAS KILLED, OTHER SUSTAINED SERIOUS HEAD AND OTHER INJURIES. WE ARE ENGAGED IN LAW SUIT WITH FORD OVER THIS MATTER. WHAT IS NHTSA DONG TO ENSURE THAT AUTOMOBILE MANUFACTURERS MAKE SEAT BACKS THAT WILL NOT BREAK IN SUCH CIRCUMSTANCES? WHY DON'T MANUFACTURERS MAKE SEAT BACKS AS STRONG AS THE SEAT BELTS? THE RESTRAINT SYSTEM IS COMPRISED OF THE SEAT PLUS THE SEAT BELTS, AND THE RESTRAINT SYSTEM CAN BE REDERED USELESS IF THE SEAT BACK COLLAPSES. *AK