Sisak refinery is a complex refinery intended for the processing of domestic and imported crude oil. It consists several combined plant and a large storage space. Most of the refinery was built in the 70s and because of the disinvestment it is quite outdated, and therefore represents a potentially high environmental risk, although last ten years there was some change. Most of the wastewater from Sisak refinery ends in rivers Kupa and Sava, and the emission of H2S, NOx, and SO2 and other harmful gases emitted from industrial plants ends in the air of the city Sisak. Water and air pollution of Sisak refinery represents a change in the whole ecosystem, which can affect the health, activity and survival of living organisms, including people., There is also a negative effect on the climate, soil, materials, and generally decreasing the quality of life. Polluted air poses a threat to human health and the ecosystem not only for Sisak, but also for the surrounding area, the duty of all citizens is to alert the authorities on the potential risks and irregularities in operations of Sisak refinery as they arise, and the legal obligations of the government and competent authorities is to ensure clean air, drinking water and clean soil for all citizens. Pollution today reduces opportunities for a healthy and happy life of future generations. The pollution problems of individual cities are not isolated cases, any such problem is also a problem of the whole country.