Paramedics are treating at least two people for chemical inhalation at a shipping company in Tullamarine.
Ambulance Victoria spokesman Shaun McComish said crews had responded to calls for assistance at a premises on Tullamarine Park Road just after 11am.
The Metropolitan Fire Brigade are also on scene, with nine trucks and up to 30 firefighters responding to a hazardous materials call-out, a spokesman confirmed.
The condition of the patients is not yet known.
