An investigation into a fire that engulfed an Air Busan plane at a South Korean airport this week is being slowed by a large amount of fuel and oxygen still on board, an air crash investigation official told Reuters.

A passenger plane has caught fire before takeoff at an airport in South Korea, but all 176 people on board have been safely evacuated.

An Airbus plane belonging to South Korean carrier Air Busan caught fire on Tuesday at Gimhae International Airport in the country’s south while preparing for departure to Hong Kong, fire authorities said.