The ACT Fire Brigade has confirmed the fire is burning within an amount of mineral oil within the building.
Firefighters are now re-commencing firefighting operations using water and foam.
The ACT Fire Brigade has now ordered the evacuation of the whole suburb of Mitchell including a number of campers at Exhibition Park.
There is still a localised smoke plume but there is no threat to nearby residential suburbs of Harrison and Franklin.
Residents are advised to remain indoors.
The building is located in the newer industrial estate of Mitchell off Hoskins Street.
Firefighters have been forced to move a few hundred metres back from the premises while working with the business operator to identify what substances are inside the building.
The business, Energy Service International (ESI), works with materials including oil from electricity transformers.
The fire has produced a thick smoke plume in the immediate area.
A 300 metre exclusion zone has now been put in place.
Three fire pumpers, bronto, hazmat, BA unit and command crews are all on scene.
The ACT Fire Brigade is working with the business operator to identify the contents of the building.
The fire has now burned through the roof of the premises as firefighters work to extinguish it.
The ACT Ambulance Service also in attendance as a precaution.
The ACT Fire Brigade is responding to reports of a large factory fire in Dacre Street at Mitchell.
Update to follow.
The ACT Department of Territory and Municipal Services (TAMS) will conduct a controlled burn tomorrow, Friday 16 September, 2011 weather permitting, at Chapman Ridge.
The ACT Handy Map grid reference for the burn is J13.
The ACT Handy Map can be found by clicking on the link on the Bushfires Home Page of this website, or on the inside back cover of the 2011/12 ACT and Region Yellow Pages phone directory.
For more information on the burn please visit www.tams.act.gov.au or call Canberra Connect on 13 22 81.