A storage tank overflowed while fuel oil was being delivered to a cheese factory. A leak occurred on the control gauge located in the basement boiler room. Approximately 50 to 60 litres of fuel oil were spilt, which polluted the Orain River via a manhole in the boiler room. An employee became aware of the leak the following day. The leak was stopped by pinching the pipe at the gauge and sawdust was spread out to soak up the hydrocarbons. At the same time, the Police Force was informed that traces of pollution were seen on the Orain. Firefighters deployed bales of hay to stop the release. The operator removed the bales three days later in the absence of any trace of pollution. However, traces of fuel oil then reappeared at the outlet of the pipe and in the river. The fire brigade put the dam back in place and closed off the pipe from the boiler room using an inflatable bladder which stopped the flow. The dam was then removed and the 6 bales of hay, impregnated with fuel oil, were placed in a sheltered storage area, pending their removal by a specialised company.

The operator had ordered 7,000 litres of fuel oil:

• 6,000 l for the main underground tank, having a capacity of 22,000 l, i.e. enough to top off the tank;
• 1,000 l in the other tank, having a capacity of 5,000 l.

The operator had offered to assist the driver with monitoring the tank while it was being filled, but the driver declined, explaining that he would have time to return to his truck to stop the filling process when a bit of foam could be seen coming out of the overflow. In the end, the driver filled 6,300 litres into the main tank and 700 litres into the second.

The operator no longer had the plans for the wastewater system, that was built between 1965 and 1968, and was not able to locate the manhole corresponding to the pipe running from the boiler room to the river. The gauge was replaced, and the discharge line located in the boiler room was closed off. Fluoresceine tracing dye was used to study the drainage system in order to block off the pipe leading to the river.