Eleven fire crews have been called to a blaze at the Muntons factory in Stowmarket.
Suffolk fire and rescue service were called to an incident in Needham Road at 6.23am on Thursday and remain at the scene.
A spokesman for the service said a dryer was smouldering grain, approximately 28m off the ground.
It is not clear yet if anyone was inside or if there are any injuries.
The fire was originally noticed in a standalone drier at around 6am, said Muntons managing and sustainability director Nigel Davies.
The incident comes several months after nine fire crews tackled a blaze at the same factory, in Cedars Maltings, in September last year.
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