According to the search results, the Luton Airport fire was caused by a diesel-powered vehicle. The fire started on the third floor of the newly-built Terminal 2 car park and quickly spread, damaging about 1,500 vehicles in the car park and leading to the temporary closure of the airport. The fire service sent more than 100 firefighters from Bedfordshire, Buckinghamshire, Cambridgeshire, Hertfordshire, Northamptonshire, and London to the car park, and it took them several hours to extinguish the fire. The exact cause of the fire is still subject to verification, but it is believed to have started with a diesel-powered vehicle.