Paramedics have treated 26 people after London City Airport was closed and evacuated over reports of a “chemical incident”.
Around 500 people were told to leave the airport and Transport for London have been warning travellers to expect “long delays”.
London Fire Brigade said firefighters and police wearing protective equipment carried out two complete sweeps of the airport building.
A spokesman said the incident has been declared over as: “No elevated readings were found and the building was ventilated, searched and declared safe.”
The airport tweeted: “Airport has now reopened. We thank passengers for their patience, access to terminal will be staggered & disruption to flights expected.”
Earlier, London Ambulance’s Assistant Director of Operations Paul Gibson, said: “We were called at 4.11pm to reports of an incident at London City Airport.
“We sent a number of resources to the scene including two single responders in cars, four ambulance crews, an incident response officer and our Hazardous Area Response Team (medics specially trained to treat people in hazardous situations).
“We are treating 26 patients at the scene for difficulty breathing, two patients have been taken to hospital.”
The boxer David Haye, who was on his way to Edinburgh to watch a fight on Friday, tweeted he was unable to travel “As #CityAirport got evacuated when everyone started coughing uncontrollably!”
The airport said passengers were told to leave the terminal because a fire alarm was sounding.
The cause of the apparent breathing difficulties is still not known.
Witness Chris Daly, who said he has been waiting on the tarmac for three hours, said: “All the fire alarms started going off. A couple of members of staff said there had been a fire. There was no mention of a chemical incident.”
Scores of passengers were moved on to the tarmac outside the terminal building.
London City Airport advised people due to fly to check with their airlines for latest flight information.
Incoming planes from destinations such as Frankfurt, Amsterdam, Belfast City and Paris had to be diverted to other airports.
First Officer James Quirke, a Cityjet pilot who is at London City, said: “Aircraft with passengers onboard are being given air traffic control clearances now, so they should be on there way soon. Everyone is moving now and the airport appears to be reopening.”
Sky’s Home Affairs Correspondent Mark White said there is nothing at this stage to link the incident at London City to an apparent terror scare at the nearby North Greenwich tube on Thursday.
He said: “We haven’t been alerted to anything sinister.”
A 19-year-old was held on terror charges after being Tasered in the street the day after a controlled explosion was carried out at the station hours before a concert was due to take place at the nearby O2 Arena.
Courtesy of Sky News