Abstract: Employees #1 and #2 were working on top of a tubular welded frame manually-propelled mobile scaffold installing metal studs as a part of drywall installation. Employee #1 was using a power activated tool to install the studs and Employee #2 was handling the drywall. During this time, the scaffold had been adequately braced and had railings, toeboards, and locked casters. The employees had worked about two thirds of the way around the room. They had not moved the scaffold while on the platform, but had first descended, unlocked the casters, and then moved the scaffold. For an undetermined reason, while the employees were working from the scaffold, the scaffold began to fall away from the wall toward the center of the room. Employee #1 rode the scaffold to the floor and fractured his pelvis and dislocated his hip when he landed on the concrete floor. When it had tilted far enough, the scaffold racked together and the platform boards come loose. Employee #2, detecting that the scaffold was collapsing from underneath him, grabbed a beam on the ceiling and hung onto the beam until he became tired, then dropped to the concrete floor, breaking his foot. Employee #3, who was working in the area, saw the scaffold falling and tried to hold it up but was caught under the scaffold as it fell. The metal parts of the scaffold cut his arm.