Raised floors and other metal structures such as cable trays and ventilation ducts have caused many problems with zinc whiskers in the past, and likely are still present in many data centers. This happens when microscopic metallic filaments form on metals such as zinc or tin that protect many metal structures and electronic components from corrosion. Maintenance on a raised floor or installing of cable etc. can dislodge the whiskers, which enter the airflow and may short circuit server components or power supplies, sometimes through a high current metal vapor plasma arc.