At a manufacturing plant for resins, electrical insulators and composite materials for thermal and mechanical uses, an explosion occurred simultaneously in the multi-blade sawing machine area of the ‘Dry moulding’ workshop and in the dust extractor area that collects all of the workshop’s glass and epoxy resin dust. The fire which broke out around the sawing machine following the explosion was extinguished very rapidly in contrast to the fire that had started in the dust extractor. The manufacturing workshop was evacuated. Whilst waiting for fire-fighters to arrive, the plant’s maintenance department contained the yard and cut off the power supply to the dust extractor. The smoke emissions stopped after 30 minutes of spraying. However, the fire-fighters continued to spray the installation for 30 minutes, then the lower part of the dust extractor was opened to allow the solid unburned elements to fall into drums. Using a thermal imaging camera, the emergency services checked that there were no hot spots on the pipe connecting the multi-blade sawing machine and the dust extractor. The overpressure evacuation hatches situated on the dust extractor had worked correctly and the explosion had no other consequences. The accident was caused by an error by the technician working on the multi-blade sawing machine. This technician returned to work during the afternoon shift. Before starting up the sawing machine that had not operated the week before, he noticed that the dampers of the 2 upper suction devices were closed and opened them. However, despite the presence of a safety instruction on the workstation, he did not check whether the damper of the lower suction device was open. After cutting an epoxy glass coil, the technician realised that the lower damper was closed and opened it, causing sudden suction of dust heated by the rotation of the sawing disks. In the dust extractor box, the concentration of dust and the ignition source formed by the hot dust created the conditions that caused the explosion. The fire extinguishing water was collected and the area was cleaned by a specialist company. The dust extractor was repaired (replacement of the filtration elements, anti-explosion hatches and electric cables). The installation resumed operation after a 2-week shutdown. The cost of the damage was estimated at €0.1 million. The operator has eliminated the closing dampers on the suction ducts.