Morowali. Three more victims from the furnace explosion at a metal processing plant in Morowali, Central Sulawesi, died during treatment at a local hospital on Monday, bringing the total number of fatalities to 16.

The explosion occurred just after dawn on Sunday at the plant operated by Chinese-funded Indonesia Tsingshan Stainless Steel (ITSS) in the Indonesia Morowali Industrial Park.

The incident instantly killed 13 workers, including nine local workers and four Chinese workers, while more than 40 workers were injured, including many with severe burns.

“Three more victims died earlier today,” said Dr Agus Partang, director of the municipally-owned Morowali Hospital.

The deceased have been identified as Irfan and two Chinese nationals Wang Ning Nang and Lie Hung Chun.

A preliminary investigation revealed that the explosion occurred around 5:30 a.m. Sunday Central Indonesian Time (9:30 p.m. Saturday GMT) while workers were conducting repairs on a smelting furnace.

The majority of the victims were identified as mechanics engaged in repairing the furnace on the facility's second and third floors.

ITSS is a subsidiary of China-based Eternal Tsingshan Group.

Indonesia Morowali Industrial Park has released a statement saying that the furnace explosion triggered subsequent explosions of many oxygen cylinders used for welding.

"The explosion took place during repair work. At that time, many oxygen cylinders were being utilized for welding and metal cutting related to the furnace," said Dedy Kurniawan, a spokesperson for the industrial park management.

According to data from the Energy and Mineral Resources Ministry, Indonesia Morowali Industrial Park owns a 10 percent stake in ITSS.

While the company commits to covering all medical expenses for the injured and providing financial compensation to the families of the deceased, specific details were not disclosed.