At 11.25 am, 3 maintenance workers were welding a shaft in a tank containing a soap solution when a fire broke out in the fume extraction hood connected to a metal duct that releases these fumes into the atmosphere. The staff raised the alarm and the siren was activated. The internal emergency services intervened at 11.30 am using CO2 fire extinguishers and the first aid hose system to cool the duct. Fire-fighters were alerted at 11:38 am, but the incident was over when they arrived 10 minutes later. However, the fire-fighters looked for any hot spots in the duct using a thermal imaging camera. Following the accident, 50 people were examined on site and 13 others were hospitalised for 24 hours. The equipment in question was placed back in operation at around 6 pm The fire was probably caused by the build-up of soot and soap dust in the duct. Indeed, on Batch off mixer 19, the strip of hot rubber that is continuously formed is washed with soapy water. Due to the temperature of the rubber, vapours or fumes are emitted and released via the building’s roof but some of the soot is deposited in the exhaust duct. This duct is cleaned once a year during the plant’s annual shutdown at the end of July. The welding of a shaft on the soap tank line had ignited the dust in the duct. A few days after the event, the health and safety department meeting considered a ban on hot work in hoods without closing them, the revision of all of the work procedures, in particular with hot spots and reviewed the issuing of the hot work permits. The plant’s management drafted a memo reminding staff of the safety guidelines. The operator is planning to install water diffusers in the ventilation ducts.