Abstract: Employees #1 through #3 were being hoisted in a skipbox to secure a scaffold cable when the derrick boom collapsed and the box fell. Employees #1 and #2 were killed and Employee #3 was hospitalized. Employee #4, who was working on the 13th floor, fell through the hole made when the box went through the floor. He was hospitalized with injuries sustained when he fell to the decking on the 11th floor. Employee #5, the signalman to the derrick operator, had been standing almost directly underneath the skipbox while it was suspended. He sustained a 3 in. cut on his forearm, either from the falling skipbox or from another flying object.