The incident occurred on an oil tanker under construction at the yard in Changwon, South Gyeongsang Province around 11:30 am local time on August 20.
At the time, the workers, in their 30s to 50s, were conducting painting operations inside the tanker at the plant which is located some 450km away from Seoul.
An explosion at the STX Offshore and Shipbuilding yard in Yonhap, South Korea, has killed four people. The incident happened in Changwon, South Gyeongsang Province around 11.30 am local time on August 20.
The explosion occurred whilst workers were conducting operations inside the tanker at the plant which is located 450km away from Seoul.
The four men, aged in their 30s to 50s, were painting the ship in the yard in Jinhae, an industrial hub on the country's southeast coast, an official from the National Fire Agency said. "No additional injuries were reported," the official said.
The 74,000 dwt tanker is reportedly being constructed for a Greek shipping company and was earlier scheduled for delivery in October.
The cause of the explosion was not familiar at the time of the reports. Local authorities have launched an investigation into the incident.