Within a distillery, the lower part of a storage tank (recently built, capacity: 1,000 m³) containing 300-400m³ of still wash opened suddenly. The wave generated first destroyed the retaining walls and then the plant’s enclosure before flowing into the adjacent watercourse. Firefighters set up a dam, pumped the still wash from the bed bottom and were thus able to limit the pollution released. Despite these efforts, high COD amounts were noted in the river and its tributaries (up to 250 mg/l in the downstream river). Many fish died. The tank was repaired and reinforced over its lower part. The retaining walls were consolidated by means of dikes erected on their external side. A weld break (due to manufacturing defect) was responsible for causing the tank to open in the first place.