At around 3:30 p.m. on a Saturday, the guard at a paper recycling company reported that white smoke was rising from the neighbouring green waste recycling company that was closed that day. The emergency services arrived on site before the facility operator. The smoke had been coming from flameless combustion on the outside of a 100/150 mm wooden windrow intended to feed the biomass boilers. The fire brigade used the site’s fire-fighting water supply and was able to extinguish the fire at around 7 p.m. The site’s wheel loader was used to isolate the burning materials from the rest of the windrow. The facility operator set up a surveillance system the following night to avoid any resurgence of fire.

The extinguishing water flowed to a retention basin. The combustion residues were incorporated into the compost and analyses were conducted to check whether or not it complied with standards.

The weather conditions may have been the cause of the accident: winds of 20 km/h, low humidity, and a temperature above 27 °C may have assisted the start of fermentation. The windrow temperature measured the day before was normal (measured every two days on the wood windrows). However, it is possible that the survey was not performed in the centre of the windrow due to its width, and therefore it was not detected that fermentation had resumed.

The facility operator modified the windrows (now 4 m wide and 3.5 m high and no longer in a wide tubular shape but in a triangular shape) and their spacing (1 m between each windrow) to facilitate temperature control at the core of the piles. The signage of its fire-fighting water supply system was also improved.