Thirteen people were killed and dozens injured in an explosion at a nickel-processing plant in eastern Indonesia on Sunday, authorities said.

The incident took place at the PT Indonesia Tsingshan Stainless Steel plant, situated in the Indonesia Morowali Industrial Park on Sulawesi island, at about 5:30 am Sunday local time (9.30 p.m. GMT on Saturday).

According to Central Sulawesi police chief Agus Nugroho, the victims included eight Indonesians and five Chinese workers. 

The fire was extinguished later in the morning, the industrial park's statement said.

Blast during furnace repair work

Initial investigations suggest the explosion occurred during furnace repair work that ignited a flammable liquid, causing the nearby oxygen tanks to blast.

"Based on initial investigations, the explosion (was) possibly caused because there was still some explosion-inducing liquid at the bottom of the furnace. During the repairing process, an explosion occurred," an industrial park official said.

The company running the park said it was "deeply saddened by this disaster," adding that the remains of several identified victims were flown back to their homes.

Sulawesi Island is a hub for Indonesia's nickel production, which is vital for electric vehicle batteries.

'Their faces were burnt'

The explosion was so powerful it destroyed the furnace and caused damage to sections of the building's side walls, according to Nugroho.

The police chief said about 38 workers were taken to the hospital, some in critical condition.

According to the news agency AFP, a photo showed bodies on orange body bags in a clinic at the complex.

"Their faces were burnt, their clothes were all burnt," a worker at the industrial complex told AFP.

The latest incident at a Chinese-owned nickel plant highlights safety concerns in Indonesian industrial facilities, particularly those operated by Chinese companies.

In January, two workers, including a Chinese employee, were killed at a nickel smelting plant in the same industrial park. Later, in June, a fire at the same plant killed one and injured six others.

ss/rc (Reuters, AFP, AP)