Two people were killed and 13 injured - including one man who remains in critical condition with third-degree burns on 99 percent of his body - after molten iron spilled from a refining furnace at a steel plant in Shanghai on Monday.

Officials at the plant, owned by Baosteel Group Corp, China's largest listed steelmaker, said the accident happened around 9:10 am when workers were clearing molten slag from the furnace.

According to a preliminary investigation by the Shanghai Administration of Work Safety, a hook lifting the furnace failed, toppling the 270-ton structure.