A fire broke out in a sodium refining workshop at a chemical plant, following the drainage of installations into a drum after a high-level alarm was activated. This same alarm had been activated several times the day before. The fire broke out in the drum containing the liquid sodium-based mixture, at the drum/mixing/air interface. While attempting to dismantle the drainage device in order to close the drum, a technician received 2nd degree burns to his hands. Due to the heat, the drum was perforated at the bottom and dropped its contents onto the ground (no retention tank). The establishment’s internal emergency plan was activated, the power in the sector was cut off and calcium carbonate was brought in to contain the fire. The internal emergency plan was lifted 1 hour after its activation. The fire affected that floor and the ground floor, and damage was limited to the workshop’s electric cables, the cost of which was estimated at €50,000. No environmental consequences were reported, apart from a cloud of sodium oxide, whose dispersion was facilitated by the meteorological conditions, that was observed from outside the site. The absorption of moisture by the oiled drum, prepared the day before in preparation for emptying, caused its contents to ignite. The high level alarm was triggered because the transfer of the reactive mixture had slowed down due to breakage of the reactor’s stirrer. Following this accident, preventive and protective measures are being taken: staff training on warning messages, preparation of the drainage drum just before emptying it to prevent any absorption of moisture, installation of a retention tank under the drainage drum, and installation of a drainage pipe fitting/fixed pipe equipped with a handle allowing it to be rapidly dismantled, etc.