The fire began at around 4:08 p.m. on Aug. 22 at a thermal plant inside the Yeosu complex. Fire authorities deployed 54 personnel and 27 vehicles and brought the main blaze under control by 6:11 p.m. Sixteen people on site evacuated; no deaths or injuries have been reported so far.

The particular problem of coal dust

The presumed cause is one to two tonnes of coal dust built up inside equipment. Coal dust has a large surface area, can self-heat when heat accumulates, and once alight tends to smoulder deep inside for extended periods. That is why full extinguishment takes far longer than knocking down visible flames.

Crews accordingly managed the remaining fire by spraying cooling water from outside, on the assumption that embers persisted within the dust. Opening the equipment would admit oxygen and could revive the fire, making this a category of incident where the approach itself has to be chosen carefully.

Generating equipment inside an industrial complex

The Yeosu complex is a large petrochemical-centred industrial site where generating facilities supplying power and steam to tenant firms sit within the complex itself. In that configuration a fire at a generating facility can directly affect operations at adjacent processes, so process stabilisation runs alongside the firefighting response.

The operator and relevant agencies will investigate the exact ignition point and cause once shutdown and mop-up are complete. Initial presumptions and final findings often differ, so a determination of cause should wait for the investigation to conclude.

That there were no casualties also means the evacuation was quick. Generating facilities inside industrial complexes generally carry modest permanent staffing, and dust fires more often progress as sustained smouldering than explosive spread, which tends to allow evacuation time. That is a statement about the outcome; whether procedures were adequate is a separate review.