The fire at Interwaste Dunedin in Ward St was attended by five fire appliances about 10.30am.
Senior station officer Pete Douglas said a skip inside the building had caught fire, filling it with smoke, and upon arrival occupants informed emergency services the bin was used for the sterilisation waste, which was a potential bio-hazard.

Despite the nature of refuse in the skip, it was determined to not be a bio-hazard and emergency services downgraded the alarm level and two firefighters extinguished the fire with the help of support crews.
The fire started in the skip and the company it belonged too was making inquiries as to how it occurred, he said.
A Fire and Emergency New Zealand spokeswoman said crews had left the scene by about 1.20pm.