During a violent storm and torrential rain, a fire broke out at around 4:00 pm in a waste storage area at a flux-cored welding wire manufacturing plant (lower-tier Seveso) following the ignition of two big-bags containing recovery fines from dust extractors. These iron, aluminium and calcium carbide-based fines had been in contact with water overflowing from roofing channels. The internal emergency plan was activated. A chemical emergency squad and 61 fire-fighters were mobilised from around ten emergency response centres. Residents were instructed to stay inside. A concentration of amines of 25 ppm was measured during the intervention. Powder extinguishers, sand and 3 t of cement were used to extinguish the fire.

The next morning, an additional 7 t of cement were poured and 10 t of sand had be to used in the afternoon to cover the waste storage area whose temperature was still 40 °C. The roof had been damaged by the fire so a tarpaulin had been installed to prevent more rainwater from entering. No aqueous pollution was reported. Production was shut down and the staff temporarily laid off.

Insufficient waterproofing of the roof and torrential rain had caused the accident. The investigation also highlighted that the internal emergency plan had not been updated following the latest increase in business. The inspection authorities drew up a report establishing the facts and recommended an emergency measures order making the resumption of the installation’s activity subject to isolating this type of storage area. The operator plans to: complete the repairs to the roofs of the buildings built in 1903 and – for the water-reactive products – to create a new covered area inside the workshops and replace big-bags with drums.