A maintenance technician discovered a fire smouldering inside a casemate (isolated and empty of all explosives) at an explosives plant that was closed for annual holidays. Upkeep work had started inside the casemate the day before. The technician gave the alert at 7:45 a.m. Two volunteer firefighters at the site doused the casemate with a nozzle supplied with water from a nearby 2000 m3 pond. The site’s internal emergency plan was implemented at 8:30 a.m. Five firefighters worked to contain the fire and the alert was lifted at 8:50 a.m. Nevertheless, due to the 100 m² casemate configuration, they decided as a precautionary measure to bring in GRIMP firefighters (Groupe d’Intervention en Milieu Périlleux) to douse it with water from the top down to prevent any new outbreak of fire.

The casemate is made of concrete and lined on the inside with metal components and wooden shingles. The fasteners holding the shingles in place were being removed with a blowtorch as part of the upkeep. Although the area had been wetted down according to procedure during and after the hot work, heating could have caused the shingles still inside the casemate to burn slowly. Damage was limited to the loss of the wooden shingles and an aerial work platform.