Up to 70 firefighters tackled a blaze at a factory building in Middleton.
The fire is understood to have involved an empty tanker, but the fire service said it spread to an adjacent building.
There have been no reports of any injuries.
Crews from Greater Manchester Fire and Rescue Service (GMFRS) were called to Simister Lane in Middleton at 3am on Wednesday morning.
Ten fire engines were at the scene.
The blaze was eventually put out, but firefighters are expected to remain at the scene throughout the day.
The location involved was only described as a 'commercial building'.
GMFRS said the incident was later scaled down and currently, two fire engines remain at the scene.
In a statement, the fire service said: "The fire, involving an empty tanker which has spread to an adjacent building, currently measures 10 metres by 20 metres.
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"Firefighters are using four jets and other specialist equipment to tackle the fire.
Firefighters have worked hard to surround the fire and are expected to remain in attendance for the day.
"Two fire engines remain at the scene and are expected to remain in attendance for the day."
No further details have been revealed.
There have also been no reports of any road closures.
