At around 8:00 a.m., a fire broke out on an industrial fryer with a capacity of 5 t of oil at a food-processing plant. One employee gave the alert while another notified the plant’s emergency response team, which controlled the fire in 15 minutes with extinguishers. By the time the firefighters arrived, the fire was under control. They cooled the fryer using two of the plant’s hose reels. The fire alarm went off and all 250 employees were evacuated. The power supplies were cut off and the firefighters ventilated the building. The oil temperature fell to 25 °C. The fryer was opened and drained. The temperature at the bottom of the tank was 60 °C. According to the operator, this was normal. Of the 17 employees who helped to put out the fire, six had symptoms of vomiting and headache. They were taken to hospital and discharged that afternoon.

The operator had planned to replace the fryer by a new one that had been built at the plant during the summer. It was supposed to be shut down at the end of the week. The fire started on the filter, which removes chip particles from the frying oil. The operator said that the fryer had been carefully maintained.

Material damage was limited to the fryer and its associated equipment. The roof opposite the fryer was charred by the flames. The fire resulted in operating losses. The line involved in the fire was shut down and the other line (line 2) was shut down but restarted that afternoon. The operator estimated that 1500 t of chips were not able to be produced.

Another fire had occurred on the hood of the fryer on line 2 in 2016.

As the ignition source was not established and the combustible material was not clearly identified, the inspection authorities for classified facilities asked the operator to seek the advice of an industrial risk specialist regarding:

• the analysis of the causes of the fire of 26 June 2017;
• the analysis of the causes of the fire of 2016;
• the analysis of the operation of the fryers on lines 1 and 2 under both steady-state conditions and transient conditions (start-up, shutdown, etc.) specifying the conditions to be met to avoid fires.