During the Kosovo War in 1999, several industrial plants in Pančevo were heavily bombed by NATO aircraft. A large part of the population had to be evacuated from the city and the surrounding areas at short notice due to the high toxic contamination of the air caused by the fires. An estimated 62,000 tons of oil burned in the NIS refinery alone.
According to studies by the American Institute for Energy and Environmental Research (IEER) and the United Nations Environment Programme (UNEP), for example, 2,100 tons of carcinogenic 1,2-dichloroethane, 250 tons of liquid ammonia and 8 tons of mercury seeped into the soil and groundwater. The concentration of the toxic chemicals detected in the groundwater was still tens of thousands of times the permissible limit years after the bombing.