In an ordinary industrial waste (OIW) storage center, fire broke out in a working storage cell after the watchman had left. The gendarmerie notified on-call staff and fire-fighters. The fire spread along the dyke wall separating cells 4 and 5, oriented perpendicular to the wind direction. First responders were encumbered for several reasons, namely large floating elements (originating from the neighbouring processing centre) in the fire water reserve basin slowing the pumping of water, and thick black smoke emitted from the ignited zone preventing the centre’s operator from bringing clay on-site. A power shovel was dispatched to the scene. The sprinkling system on the composting platform’s retention basin was activated. The blaze was brought under control after a 14-hour battle and completely extinguished 3 hours later, once the enflamed zone had been covered by clay. The geomembranes of cells 4 and 5 were partially deteriorated. Site operations were shut down for 10 days. Malicious intent was the cause of this accident, as evidenced by: the presence of a hole in the fence, the existence of 2 distinct outbreaks, fire initiation after the watchman had left. Following the accident, extinction water was discharged and the geomembranes of the affected cells were repaired as was the fire water basin (cleaning and scouring). To ensure the absence of environmental impacts, analyses were conducted on piezometers installed downstream of the site. The means of prevention and protection were reinforced: a protective net was placed above the fire water basin; the operator scheduled monitoring rounds; both the safety report and first responders’ action plan were revised; and operating conditions were modified (including smaller operating areas, allocation of a stockpile of capping clay at various site locations, improved waste compaction at the periphery of storage cells by introducing protective geomembrane earth covering).