Four contract workers died Thursday after inhaling an unidentified gas in an oxygen cooling tower at steelmaker POSCO's factory in Pohang, North Gyeongsang Province, according to police.
Officers said the victims were replacing interior material inside the cooling tower used to provide oxygen to a blast furnace and are thought to have inhaled leaking nitrogen. It's unclear where the gas leaked from. Nitrogen itself isn't harmful, but can kill people when there is a lack of oxygen. A police investigation is ongoing to find the exact cause of their deaths.
An officer said all four contract workers were wearing protective gear when the incident occurred. POSCO said the victims had just started to work following a 30-minute break when they all collapsed.
The youngest victim was 26 year old, while the oldest was 60.