An employee was removing packaging supplies from a vertical reciprocating conveyor (VRC) or full-size freight elevator lift box. The two master links that connect the chains on each side of the gate to the counterweights failed and the inner door/gate fell down onto the employee and knocked her down to the ground. The door then bounced back up and came down onto the employee's leg. The employee sustained a fractured tibia and fibula, compression fractures to vertebrae, and a collapsed lung.