A gas leak in a boiler room at a hotel in Gyeongju, North Gyeongsang Province, killed one and injured six Saturday, officials said.
A 45-year-old hotel employee surnamed Park died from carbon dioxide poisoning while working in the underground boiler room at Colon Hotel, the police said. Six others were hospitalised for minor injuries, they added.
"The fire alarms suddenly rang while (they were) replacing the insulators, and then there was a leak of carbon dioxide," the wounded workers testified to police.
Investigators suspected that the fire extinguishing system had been damaged while an insulator was being replaced. The fire extinguishing systems of boiler rooms or machinery rooms are not equipped with water but with carbon dioxide due to the threat of electric shocks.
While no fire was reported at the scene of the accident, the workers could not evacuate due to an automatic fire-containment door, police said.
About 60 hotel guests immediately evacuated from the building, police added.
An investigation to determine the exact cause of the accident is underway, authorities said.