Fire crews from Rushden, Wellingborough and Corby are assisting Bedfordshire Fire at a large blaze in Milton Ernest.
Smoke from the huge fire at Twinwoods Business Park, a few miles from the county border, has been seen as far away as the Irthlingborough area.
Bedfordshire Fire and Rescue said it was on the scene at 1.03pm. It declared the blaze a major incident but said all people have been accounted for.
It has been estimated that 80 per cent of the building has been engulfed in flames.
Bedfordshire Fire added that a large number of plastic cylinders reportedly involved in the fire and flames had reached four floors of the building.
There are eight fire engines on the scene, including a high volume pump from Corby which has been drafted in to help put the flames out.