The 2000 Baia Mare cyanide spill occurred when a dam (operated by Aurul, a joint-venture of the Australian company Esmeralda Exploration and the Romanian government) holding 100,000 tonnes of cyanide-contaminated tailings spilled into the Someș River and from there into the Tisza and Danube. The spill created a large-scale environmental disaster that has been called the worst environmental disaster in Europe since the Chernobyl disaster.