An electrical fault in a vehicle sparked a blaze which has gutted a recycling plant in March.
The NCB Commodities warehouse was ravaged by flames on Tuesday night, causing more than £500,000 worth of damage.
Ten crews from across Cambridgshire and Norfolk were called to the warehouse in Creek Fen after fire broke out just after 5.30pm.
Luckily no-one was in the building at the time of the incident.
Firefighters were able to contain the fire in the warehouse and prevented it from spreading to two nearby buildings.
The flames were extinguished by 9.30pm.
Group Commander Sean Brown, the officer in charge of the incident, has praised the firefighters.
He said: “The crews arrived to find a fire in a factory unit containing recycling material.
“The premises was closed for the night so no staff needed evacuating.
“More resource was quickly requested to stop the fire spreading to other nearby units. The crews did a fantastic job by acting quickly and decisively to ensure the fire didn’t spread.
“This is a timely reminder for factory and business owners to ensure their fire risk assessments are up to date and reviewed regularly.
“Our Fire Protection team holds regular seminars for businesses to provide information about fire safety in the workplace.”
Crews from Dogsthorpe, Stanground, Yaxley, Whittlesey, Thorney, Wisbech, March, Chatteris, Huntingdon and Outwell attended.
An investigation found the source to be a fault within a vehicle inside the building.