Employees were transferring a finished sheet of plastic to a material table using a gantry crane with a vacuum lift attachment. Once it was on the table, the employees unhooked the vacuum lift attachment from the gantry crane hook and placed the attachment on the table. The employees then began to move the gantry crane hook when it caught the attachment and caused it to tip over. As the injured employee went to stop it from tipping, the equipment pushed the employee back, causing him to roll his ankle and sustain a leg fracture.