About a thousand liters of sulfuric acid leaked from the construction site of a smelter factory in the country's industrial city of Ulsan Tuesday, injuring six workers, firefighters said.
The incident took place at around 9:15 a.m. at a factory owned by Korea Zinc Inc., the country's largest zinc smelter, some 414 kilometers southeast of Seoul.
The chemical at some 70 percent concentration leaked as six workers were disassembling pipes for maintenance. All six are suffering from burns, with three of them in critical condition, authorities said.
Firefighters said they are investigating whether there is any secondary damage from the accident.