In a 12,000-tonne silo at a farming cooperative, alfalfa began to self-heat in a 2,500-tonne storage cell filled with 1,800 tonnes of pellets (since Aug 2003). Site personnel discovered the accident during a drainage operation when just 150 tonnes of product were left in the cell. They attempted to contain the outbreak using the cooperative’s internal resources, but these proved insufficient. Combustion spread and, as of the next morning, had generated considerable smoke seen to be leaving the building. Once notified, civil protection authorities evacuated some 30 residents within roughly 100 m of the silo. Nearly 50 fire-fighters reduced pellet combustion by pouring foam and then extracted the pellets via a hatch placed at the base of the cell. This response was slowed by the accumulation of combustion products and would continue until the morning hours 2 days later. Additional resources were introduced to disaggregate the alfalfa clumps (a high-pressure hydraulic hose). On Saturday evening 3 days after the initial outbreak, product combustion was stopped, leaving in the cell nothing more than a sludge composed of water and plant matter.

During the accident, 150 tonnes of alfalfa pellets were destroyed and a scraper conveyor (equipment used to drain the cell) was damaged. No temperature reading of stored products had been taken since the cell was filled in August. For this type of storage, inspections rely on mobile thermal sensors composed of thermometers fastened to the ends of metal rods. According to the facility operator, filling to two-thirds of cell capacity would have prevented installing such devices atop the pellet heaps, as the 4-5 m rod was too short. The intense heat of summer 2003 also complicated the cooling of alfalfa pellets prior to their storage.

Administrative authorities recorded these facts. The inspection authorities for classified facilities proposed that the local government authority issue an injunction to comply with provisions set forth in the a governmental order (calling for stored products to be controlled with thermal sensors) as well as with an order to suspend silo filling until all cells had been equipped with temperature control systems adapted to every storage configuration.