Pollution
Humain
Environnement
Economique

Inside a wood panelling factory, 3 explosions occurred within a span of 15 seconds around 10 am adjacent to a production line. The affected zone extended from the auger located downstream of a dryer to the wood chip silos at the end of the sorting zone, before the gluing step. These 3 blasts spread throughout the line, damaging both the silos and conveyor belts. The chips contained in the silos heated and ignited, triggering fire outbreaks. The factory operator activated the site’s internal emergency plan at 10:15 am. Given the risk of a secondary explosion, it was decided to install a 100-m safety perimeter.

The factory was undergoing maintenance at the time. Six subcontractors were on-site working near the blasts, which caused 8 injuries, including 2 of a serious nature (burns to the face and forearms). Of the 8 injured, 5 were subcontracted employees. After being moved to the showers/locker area (gathering point listed in the emergency plan), the injured were transported to hospitals in Bordeaux, Dax and Bayonne.

First responders arrived quickly on the scene with over 50 fire-fighters deployed. Their intervention also consisted of cooling the storage silos and inerting the atmospheres of containers (creating a foam blanket via the vents) before draining these vessels. No consequences beyond the site were reported: no explosion or discharges upsetting the neighbourhood, retention of extinguishing water in a dedicated basin. The internal emergency plan was lifted at 7:30 pm. Partial redundancies were nonetheless announced on 27 April, lasting until the end of May.

A judicial inquiry was conducted to determine the causes of this accident. After an investigation by the inspection authorities for classified facilities, it appeared that a grinding operation on a poorly cleaned pipeline of the conveyor belt dust removal system was the culprit. This operation had not required issuance of a hot work permit.

The large number of vents on the conveyor network plus the presence of silos undoubtedly limited the damage resulting from the accident. The operator adopted several measures:

  • revising the site’s internal emergency plan (installing an evacuation siren, designating gathering places) ;
  • improving hot work permitting with a ban on simultaneous interventions ;
  • specifying the cleaning instructions and keeping a dedicated log ;
  • decoupling zones so as to prevent fire from spreading and/or an explosion by means of both passive safety systems (removal of bypasses and connection components) and active systems (automatic sprinkling relayed to a detection system).