A around 2 pm on 18/05, a power cut caused 2 refinery units to shut down and placed significant strain on the torch system. At around 2.30 pm, when the units were restarted, a fire broke out at one of them – a vacuum distillation unit. The internal emergency plan was activated and the internal emergency services brought the fire under control at around 3 pm. External fire-fighters came to the site but did not need to intervene. Staff were evacuated. There were no casualties during this event. A loss of high voltage power may have initially resulted in the loss of the low voltage grid, which particularly affected the operation of the vacuum distillation units, the naptha hydrotreatment and the bitumen sector. Following anomalies in the back-up power supply ensured by inverters and diesel generators, the vacuum distillation and naphta treatment units shut down, placing significant strain on the torch system. A crisis centre was activated on site at this stage. At around 2:10 pm, the high and low-voltage networks were restored, and the start-up procedures had begun. At around 2:15 pm, a major fire was detected on the previously shut down vacuum distillation unit. The circuit’s gases were sent into the torch network where a large amount of unburned gas was incinerated. The fire extinguishing water was collected with a view to subsequent treatment. After the event, an emergency measures order was implemented by the Prefect on 19/05, as recommended by the inspection authorities for classified facilities. The vacuum distillation unit damaged by the fire and its downstream equipment (diesel dryer and vacuum system, in particular) were kept shut down: investigations were carried out regarding the condition of the equipment and its replacement. Finally, the start-up procedure for the unit began on 29/05. The other units shut down (atmospheric distillation and hydrotreatment) during the fire resumed their operations after 20/05.