Firefighters say the blaze at a Lichfield factory is “likely to burn for some time”.
Glynn Luznyj, from Staffordshire Fire and Rescue Service, said: “Crews were faced with a large area of baled waste inside the building on fire.
“The fire is likely to burn for some time and as a result there is a significant smoke plume. A multi-agency group is working together on site to mitigate the impacts of the incident on surrounding areas including road and rail infrastructure.”
People living nearby have been advised to keep windows closed, while drivers in the area are also being urged to turn air conditioning off inside their vehicles.