Abstract: EMPLOYEE #1 WAS PART OF THE ERECTION CREW WHOSE JOB IT IS TO CONNECT A TOWER OF AN AUTOMATED RETRIEVAL SYSTEM. A TOWER IS TWO SETS OF UPRIGHTS 80 FEET TALL WITH 12 DOWN AISLE SUPPORT ARMS THAT ARE ERECTED ON SITE. THE UPRIGHTS WITH THE DOWN AISLE ARMS ARE SET IN PLACE WITH A CRANE. WHILE THE UPRIGHTS ARE STILL SUPPORTED BY THE CRANE, T HE ERECTION CREW CONNECTS SOME OF THE DOWN AISLE SUPPORT ARMS TO THE UPRIGHTS THAT ARE SET. WHEN THE UPRIGHT IS SECURED IN PLACED THE CRANE IS UNHOOKED SO THAT IT CAN PICK UP ANOTHER UPRIGHT. AT THIS TIME THE ERECTION CREW WILLCONNECT THE DOWN AISLE SUPPORT ARMS THAT WERE NOT CONNECTED THE FIRST TIME. THE DOWN AISLE ARMS ARE CONNECTED TO THE UPRIGHTS BY 6" BOLTS AND NUTS. EMPLOYEE #1 WAS MAKING THE DOWN AISLE SUPPORT ARM CONNECTIONS WHENSHE UNDONE THE NUTS ON THE SUPPORT ARM ABOVE HER, THE ARM WAS ONLY CONNECTED ON THE END WHERE THE NUTS WERE REMOVED. THIS ALLOWED THE 30-50LBS ARM TO FALL. THE EMPLOYEE WAS WORKING 25' ABOVE THE GROUND AND HADNOT TIED HER SAFETY BELT AND LANYARD OFF. SHE FELL TO THE CONCRETE FLOORBELOW BREAKING HER ARMS, FEET AND PELVIS