A blaze at two industrial units in Mansfield is believed to have started accidentally.
Crews from Mansfield, Ashfield, Blidworth and the specialist rescue unit from Newark were called to the buildings on Sheepbridge Lane shortly before 3am on Thursday.
A Nottinghamshire Fire and Rescue Service spokesman said: "Both units were well alight when crews arrived.
"The fire is believed to have started in a waste recycling unit and spread to a neighbouring engineering unit.
"Firefighters worked through the night to extinguish the fire."
On Friday afternoon, the spokesman added: "A fire investigation is now complete and it is understood that the fire started accidentally."