At around 9:00 a.m, a tank of plasticiser (chlorinated paraffin) located at a cable manufacturing plant overflowed into its retention system following a delivery error made by a contractor. The driver unloaded the plasticiser into a tank that was neither empty nor of sufficient capacity.

A specialist company pumped out the 10 m³ of overflow at around 11:00 a.m. Two days later, people reported to the town hall that a sheen could be seen on the River Furan. The town’s technical departments alerted the plant at around 2:00 p.m. Water samples were collected, and the outlet of the site’s storm water system was plugged.

According to the operator, the porosity of the retention system or an unknown resurgence in the storm water system might be the cause of the flow into the natural environment. The inspection authorities for classified facilities requested a report detailing the incident’s causes, circumstances, and consequences and the measures taken to prevent it recurring.

The operator resealed the retention system, cleaned out the site’s old systems (which contained hydrocarbon deposits that caused the sheen to appear on the river after the retention was washed), removed unused storm water pipes, repaired damaged sections of pipe, and made deliveries safer by fitting fool-proofing devices on the connections.

The unloading procedure was supplemented and now requires the presence of a plant manager at the start and end of unloading. In 2014, a plug will be fitted on the storm water discharge pipe leading to the river and the walls of the retention system will be raised.