At nearly 2 p.m. on April 9th, a submarine named "Hong Bum-tu" that was undergoing major repairs suddenly caught fire at the Hyundai Heavy Industries shipyard in Ulsan, South Korea.

There were 47 people on board at the time, including shipyard employees and outsourced workers. When the alarm sounded, 46 people evacuated one after another, but a female cleaner in her 60s failed to come out in time.

The fire department arrived at the scene promptly and dispatched 57 firefighters and 31 pieces of equipment to extinguish the fire. The blaze was extinguished around 4 p.m., and rescue personnel subsequently entered the cabin to conduct a search. After approximately 40 minutes, the missing person was located.

As of now, specific details such as whether she has regained consciousness or received treatment have not been disclosed to the public.

The "Hong Fantuo" is a 1800-ton conventional submarine that has been undergoing major repairs at the shipyard since June 2025, including equipment dismantling, system overhaul, and component replacement.

However, there was no welding or other open-flame operation taking place at the scene when the fire broke out. Preliminary judgment suggests that there may have been a problem with the electrical system.

The internal space of a submarine is inherently narrow, with complex passageways and strong airtightness. Once a fire breaks out, smoke will quickly fill the cabin, posing great difficulties for evacuation. Jobs like cleaning are usually undertaken by outsourced personnel, and when working in high-risk areas, safety coordination and emergency response mechanisms are also put to the test.