London City Airport was evacuated on Friday afternoon and more than two dozen people were treated for breathing difficulties after what the emergency services described as a “chemical incident.”
Around 500 passengers and staff were evacuated as a number of people began to feel unwell.
Ambulance crews treated 26 people at the scene who had difficulty breathing and two people were taken to hospital.
The airport, which is near London’s business district and is popular with businesspeople, reopened a few hours later.
Firefighters and police in protective clothing swept the airport building twice but no elevated readings of chemicals were recorded.
Flights have been severely affected.