Firefighters and an airline official have been taken to hospital as emergency services battle a fire which broke out at Luton Airport shortly before 9pm on Tuesday.
Five people were admitted to Luton and Dunstable hospitals with smoke inhalation.
A sixth person was treated at the scene but did not require further medical attention.
The newly constructed car park at Luton Terminal 2 has partially collapsed, Bedfordshire Fire and Rescue Service has confirmed, as crews work to control the blaze.
It is unclear whether passengers are stuck on the tarmac, inside the airport or in the Terminal 2 parking lot.
Bedfordshire Fire and Rescue, Bedfordshire Police and East of England Ambulance remain at the scene.
Officials at Luton Airport have confirmed that access to the airfield is currently restricted.
Passengers on flights departing from Luton have been asked to stay away from the area.
People living nearby have been advised to stay away and keep their windows closed to reduce risks to their health.