At around midnight, a 20-m stretch of the wall of a pig farm building, which was mounted on grating over a deep pre-pit, collapsed. The collapse caused 600 m³ of liquid manure to flow along a path and to a nozzle that led, via a stream, to the River Jaudy. Neighbours alerted the firefighters. More than 100 pigs were found around the farm. Some were dead and others were injured. A veterinarian euthanized a few of them at daybreak. The firefighters placed bales of straw along the path and at in the nozzle’s inlet. The roads leading to the farm were closed to traffic. Large numbers of the river’s aquatic life, including protected species, were killed along a 13 km stretch. The drinking water pump station was shut down. Fishing on the Jaudy was prohibited downstream of the pollution and all the way to the river’s mouth.

Its water quality was monitored over several days. The inspection authorities for classified facilities arrived at the farm two days later and saw that:

• A risk of a secondary accident occurring was not considered.
• An earthen bund had been placed 15 m away from the collapsed building and that 150–200 m³ of liquid manure mixed with earth and stones had been scraped up and dumped on a nearby grassy plot.
• Partition walls (which were highly suspected of containing asbestos) and waste stored near the pig farm (corrugated asbestos-cement sheets) had been carried away by the liquid manure. This mixture was sent away for disposal by the approved routes.

Services from the town hall cleaned the liquid manure off the streets. The nozzle was cleaned using a vacuum tanker. A specialist firm took away the 400 t of waste that was removed. The Jaudy was left untouched so as not to damage the natural environment.

The building was erected in 1989 and made of concrete masonry units and asbestos-cement sheets. As its pre-pits were full, the building gave way under the pressure of the liquid manure.