Fire broke out in a dust removal filter of a grape-seed dryer within a facility producing refined fatty oils. In noticing smoke rising above one of the 2 filters, the operator opened an inspection hatch at the end of the screw designed to evacuate the dust generated during dryer operations. The operator observed the presence of embers and proceeded to sprinkle them with the fire hose before calling the emergency rescue team. Fire-fighters began by cooling from the outside, then extinguished the blaze from the inside. The extinction water was collected in an oil cake storage pit. Following a battery of filter adjustment tests, a pressure surge had broken the safety membrane and sealing lid. While the membrane had been replaced, the lid had never been reset. Water infiltrated via the clamping bolt on the membrane, causing fermentation of trapped dusts and their eventual self-ignition. By injecting water, the operator dispersed the embers, which in turn led a sleeve to ignite.