Around 30 firefighters are tackling a major blaze on an industrial estate in Corby.
6 appliances are at the scene on Brunel Road.
People living nearby are being urged to keep their windows and doors closed as a precaution.
A Fire Service spokesman has told Connect FM the alarm was raised just after 5am this morning.
2 crews from Corby went to reports of a fire in an industrial unit.
On arrival, extra back-up was called in with the building well alight.
Appliances from Rothwell and Kettering raced to the scene, as well as two from Leicestershire.
The blaze had broken out in a range of units inside another unit.
The fire was contained around 6.20am but crews remain at the scene.