Pipeline DN 400 Opatovac-Slobodnica of the total length of 105 km, was constructed in 1968 and its original purpose was to transport oil from Opatovac terminal to an oil refinery near Slavonski Brod, Croatia. When it was constructed it was made in five sections. Four of them was already converted to pipeline for natural gas transmission but the last and the most demanding section, of the total length of 5,5 km must be converted to a pipeline for natural gas transmission by the end of the year 2018.

The problems with this last section is that it is not in operation since the 1990, additionally it was damaged during the war for independence in Croatia, it is not cathodic protected and it’s unpiggable so general conditions of pipeline is unknown, including the condition of coating. Also these section is not connected to Croatia natural gas transmission network and on pipeline route there is a river crossing, five road crossings and forest area of about 20.000 square meters grown on pipeline route over last 27 years.

In normal operation, the gas pipeline is a closed system that has no environmental impact. Gas quantities at the controlled discharge of an individual pipeline section are considerably reduced compared to the classic discharge method, so that the impact of gas on the environment has been reduced to a minimum.