At around 7 pm in a frozen products company situated a few hundred metres from town-centre housing developments, a fire broke out on one of the eight compressors located in a 15 x 17 m (250 m²) room storing the establishment’s refrigeration installations, 11,000 l of ammonia and 400 l of hydraulic oil. The thick smoke released had a strong odour resulting from a leak of around 100 l of liquid ammonia onto an overhead pipe exposed to heat (domino effect). The establishment’s technicians isolated the installation by closing two valves. The establishment’s internal emergency plan was activated and a safety perimeter was set up. A chemical emergency squad took toxicity measurements in and around the periphery of the establishment (168 ppm of NH3 measured close to the room or on that floor and a pungent odour over the industrial area). A water curtain was set up in order to clean and dilute the cloud. The fire was fought using a small hose on a fire engine supplied by a fire hydrant located 200 m from the plant and controlled after 4 hours of intervention. The rooms were ventilated, then the operation was suspended at 6:15 am. There were no casualties and in principle no temporary lay-offs are planned. A subcontracted refrigeration technician carried out a complete inspection of the installations (safety devices, general operation) and then 6 compressors were restarted in the following hours. The compressor that caused the fire and a second compressor whose electrical circuit had been damaged were kept shut down. The fire detection system was also repaired. The installations were monitored by qualified technicians around the clock until the situation returned to normal.