Two people were taken to Dunedin Hospital by St John ambulance, after they came into contact with diluted sulphuric acid.
A Fire and Emergency NZ spokesman said appliances from Dunedin Central, Willowbank, Roslyn and St Kilda stations were called to the incident about 9.30pm on Tuesday, and could smell the chemical from outside the building.
"Looks like there was possibly a spill of a chemical.
"They did say that it was contained to a small area. Looks like we removed the container to make the scene safe," he said.
A Hato Hone St John Ambulance spokeswoman said a crew was notified of the chemical incident at 10.15pm, and two ambulances and one operations manager were sent to the scene.
"Two patients, both in moderate condition, were transported to Dunedin Hospital.
"One additional patient, in a minor condition, was assessed and treated at the scene."
Otago Polytechnic operations deputy executive director Max Sims confirmed emergency services from Fenz and Hato Hone St John responded to the incident on campus.
"A contract cleaner alerted a member of campus services staff to investigate an incident at P Block — the Dunedin School of Art, on Riego St.
"The incident related to an item of equipment used by the School of Art to clean jewellery, using sulphuric acid diluted with water.
"There was no spillage of this cleaning agent.
"However, two individuals — one staff member and one contractor — were taken to Dunedin Hospital and were discharged early this morning after an observation period."
Mr Sims said there were no students in the building at the time because formal studies had largely wrapped up for the year.
He said there was no damage to property, and Fenz officers informed staff that the building was safe to occupy again after the area was neutralised and ventilated for a period.
"Otago Polytechnic will be reviewing its procedures and management of hazardous substances in the School of Art following this incident, to ensure all precautions are being taken to ensure the safety of staff and students when handling dangerous chemicals and other substances."
