A Fire Service spokesman said firefighters from three stations - Dunedin City, St Kilda and Willowbank - were called after a sulphuric acid spill at Otago Waste Management Services in Wickliffe St about 1pm.
The refuse station was cordoned off, as the crews and Otago Regional Council staff investigated.
Council environmental monitoring and operations director Scott MacLean said six containers, each with a 10 litre capacity, had sulphuric acid labels and various quantities of the highly-corrosive acid inside.
The acid had been ''dumped illegally'' in the trade waste bay at the transfer station, he said.
A machine operator at the station noticed the containers, prompted the closure, and called the Fire Service and council.
A ''modest amount'' of the acid was lost but was contained in a sump system and would not have entered a stormwater system, Mr MacLean said.
''There is no danger to the public and the environment,'' he said.
Council staff had started an investigation to find the party responsible for dumping the acid, including reviewing CCTV footage from the station.
