An explosion inside a POSCO plant on Tuesday killed one worker and inured two others. 

Police and firefighters are investigating the cause of the blast at the company’s stainless steel plant in Pohang, North Gyeongsang Province.

A 28-year-old employee of the steelmaker’s affiliated company was killed at the scene and two colleagues of his in their early 30s were seriously injured, police said.

Officials said it may have been caused by blast-furnace gas. The explosion  did not lead to a fire at the plant.