Animals from a nearby pet store had to be rescued as a large blaze took hold at a timber yard in Long Eaton on Friday night.
Ilkeston firefighters were joined by cres from Long Eaton, three from Derby and one from Nottingham as they tackled flames at Acton Business Park in Fields Farm Road, at 8.45pm.
It has now been confirmed that the fire was caused by a fridge that overheated.
Firefighters spent several hours at the scene.
Today (Saturday), Clive Stanbrook, station manager at Derbyshire Fire and Rescue HQ in Littleover, said the fire started accidentally in the office of a shed.