A closed skip containing 3 m³ of hazardous industrial waste caught fire at 6:23 a.m. at a polymer manufacturing plant. Noticing a hot smell, the plant’s employees looked for its source. They saw smoke coming out of a skip located outside the plant’s hazardous areas. The operator implemented the site’s internal emergency plan. At 6:57 a.m., the employees extinguished the fire with powder extinguishers and a fire hose. The firefighters arrived afterwards and finished cooling the area.

The fire was caused by autoignition of waste contaminated with a fatty acid that had recently come into use at the plant. This fatty acid spontaneously ignites when adsorbed into a porous material. In the present case, the fatty acid’s autoxidation provided the heat source. These properties were not identified by the operator because the liquid is not hazardous in bulk. Exposure of the skip to sunlight may have contributed to the ignition of the fire.

After the accident, the operator established a procedure for handling waste contaminated with this fatty acid. This procedure is based on practices at other sites in the group. Waste is now placed into closed bags to limit its exposure to air. The operator alerted its employees of the risk associated with this waste and asked them to be vigilant about the presence of oily rags and insulation at the plant. It also informed its partners, particularly the waste treatment companies it works with.