The hazardous materials crew is investigating a substance which has leaked from a delivery vehicle overnight at a Hume business.
As a precautionary measure, about 35 staff have been evacuated from the site on Tralee Street.
The area has been isolated as the firefighters determine what the substance is.
ACT Fire & Rescue was called to the incident about 7:30am this morning. In addition to the hazardous materials unit, two pumpers and a commander are on scene.
There is no threat to surrounding businesses.