The Sovjak pit is a natural karst sinkhole which was used from 1956 to 1990 for uncontrolled and improper disposal of hazardous waste.
Remediating this site is one of the most complex projects in the environmental protection sector.
The activities are likely to last until 2026, and 85% of the necessary funding has been ensured from EU funds while the remaining 15% is being covered by the Croatian Environment Protection Fund.
It is estimated that about 250,000 cubic meters of various waste was disposed of in the pit by the 1990s. For example, acid sludge was often disposed of there, a waste material generated as a by-product during the production of lubricants, motor oils and asphalt, as was waste asphalt from coke ovens, waste oils and fuel oils from shipyards, residues from storage tanks for oil and petroleum products.