Crews have worked tirelessly at the scene in Lower Horseley Fields since it broke out at 9pm on Monday.
A spokesman for West Midlands Fire confirmed firefighting had ceased at 10.35am on Thursday.
The spokesman said: "Firefighting has ceased. Three fire crews at the scene, keeping a watching brief in case any hotspots flare up. Our investigators are also there."
The cause of the blaze remains unknown.
It comes as drone images taken by Express & Star photographer Tim Thursfield reveal the sheer scale of the blaze, which spread through factory units near to a gas depot.
Crews revealed the major incident involved some active businesses after it was initially reported the fire was contained to derelict factory units.
Several roads including Willenhall Road, near to the building where the blaze broke out in Lower Horseley Fields on Monday, remains shut three days later.
Willenhall Road is closed between Shakespeare Street and Walsall Street, junction with The Harp Inn.
Lower Walsall Street is also closed between Lower Horseley Fields and Hickman Avenue. Diversions are in place.