A large blaze at a factory in Somerton has now been brought under control.
50 firefighters were called to Freight Dve after reports of smoke billowing from the roof just before 6.45am this morning.
A number of people have been evacuated from the area.
MFB has said that the fire had started in an oil vat inside the building and was under control within 30 minutes.
Thick smoke in the area has now moved south after a wind change.
A community advice message has been issued for residents in Campbellfield, Coolaroo, Craigieburn, Epping, Roxburgh Park and Somerton.
People have been told to stay away from the area and to close all windows, doors and turn off heating and cooling if they are sensitive to smoke.