A discharge of black wastewater polluted the Selle River and caused fatalities among the fish population. An alert was sounded during the morning of the following day. The pollution occurred subsequent to the deficiency of a pumping station at the city’s purification plant, leading to the direct spill of wastewater (discharged from a dry cleaners) into the natural environment via the overflow chamber.

The general station circuit-breaker, turned off at the time, was responsible for the accident. Once it had been turned back, normal operations could be restored. This malfunction would have been due either to vandalism (signs of forced entry into the electrical cabinet) or to the intense heat. Moreover, network remote monitoring was running in a degraded mode: a thunderstorm a few days prior had destroyed the remote transmission equipment at the pumping station, with information on system flaws not being relayed to the monitoring station. These safety devices could not be replaced due to an inventory shortage in the maintenance workshop, and many equipment replacements had to be carried out since the beginning of the month due to the frequent occurrence of thunderstorms.