In a wood panel manufacturing plant, a fire broke out at the exit of a chip drier in the ventilation system’s cyclones and ducts. The fire department was alerted as a precaution, who set up 4 small fire nozzles. This incident, apparently known by the operators, was due to the progressive clogging of the ducts and cyclone. Cleaning of these elements was foreseen every 6 weeks during maintenance operations. The operator had reduced this interval to 3 weeks and the next cleaning operation had been scheduled for 2 days later.