More than 60 firefighters are working to put out a blaze at a factory in Oldbury.
West Midlands Fire Service said it was called to a large industrial unit fire on Rood End Road Industrial Estate at about 05:30 BST on Saturday.
Ten engines and two hydraulic platforms are at the scene along with specialist units.
The service said the incident would last a significant amount of time and advised residents to keep doors and windows shut.