Around 80 litres of diesel fuel has leaked from a semi trailer in Fyshwick.
ACT Fire & Rescue was called to a car park on Pirie Street around 5am.
Firefighters have put absorbent on the fuel and emptied the remaining fuel from the semi trailer.
Fire crews prevented the fuel from entering the drain.
The Environment Protection Authority has been alerted.
One pumper, Hazmat and a Commander are on scene.