Cyanide poisoning has existed for centuries. In most cases, cyanide is combined with other toxic substances; for example with carbon monoxide in fire smoke. Cases of pure cyanide poisoning are rare, and usually due to accidental exposure. Their treatment is based on oxygenation and the infusion of hydroxocobalamin. The seriousness of this type of poisoning calls for a rapid and specific response, which demonstrates the usefulness of non-hospital based medical treatment. The authors report here the case of a man who was the victim of occupational poisoning with sodium cyanide and who was treated at the workplace by fire-fighters and the Service Mobile d'Urgence et Reanimation emergency ambulance service.