Two people were killed and four others were inured following a nitrogen leak at a plant operated by the technology manufacturer LG Display Co. in South Korea.

One of the four staff and contractors that were injured remains in a critical condition.

When the alarm was raised, emergency workers found one person dead at the scene while another died en route to hospital – as reported by a state-run news agency. The leak occurred early Monday (today) at the company’s factory in Paju – about 25 miles from Seoul.

Workers and subcontractors on the premises were carrying out routine maintenance work when the incident occurred. According to a firefighters report a nitrogen gas cylinder was open by mistake – which caused the situation. The four workers, all reported in their 30s, were taken to four hospitals in the area.

Nitrogen is used to wash the display panels when they are being manufactured. Although it is not a toxic gas, nitrogen can cause asphyxiation by displacing oxygen in the air due to being a less dense gas.