Fire crews who went to a city factory after reports of a door on fire found several seats of fire inside the building.
Two crews from Leicester's central fire station responded to the incident at 5.48am yesterday.
Once there firefighters discovered the other fires inside the two-storey building and called for reinforcements from the city's western fire station.
Wearing breathing equipment, they had put out all the fires by 7am.
The cause is under investigation.
