Derbyshire Fire and Rescue received a number of calls around 3.30pm today after reports of an explosion at a disused Thornton's factory in Belper.
People were reported to be inside the building at the time of the explosion but everyone is accounted for.
Fire crews are now damping down and the fire is under control.
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Dry for much of the Wednesday with possible brighter spells in the east. Outbreaks of rain will spread southwards later in the day.
Wednesday will be another rather cloudy and mild day. Although dry for most the odd spot of drizzle is possible, mainly over high ground.
Plans have been unveiled to regenerate the Broadmarsh area of Nottingham city centre. Works are to start next year.