Evacuation of Heathrow Terminal 4 was a 'mass hysteria event' after incident 'snowballed'
The evacuation of Heathrow’s Terminal 4 yesterday was a suspected ‘mass hysteria’ event, a police source has said.
Listen to this article
The terminal was evacuated yesterday afternoon due to a suspected ‘possible hazardous materials incident’.
Terminal 4 check-in was shut at around 5pm and members of the public were urged to avoid travelling there as specialist crews responded.
Around 20 people were injured during a chaotic evacuation of the terminal but "no trace of any adverse substance was found", the Metropolitan Police has said.
A source later said the incident was being dealt with as a ‘mass hysteria event’ which ‘snowballed’ out of control.
A London Ambulance Service spokesperson said 21 patients had been treated and one had been taken to hospital, while all the others had been discharged at the scene.
In a statement, a spokesperson for the force said: "On Monday, September 8 at 16:56hrs police were called to a potential hazardous materials incident at Heathrow Airport, Terminal Four.
Read more: Peter Mandelson’s 'birthday message and photos for best pal' Epstein revealed
Read more: Greta Thunberg's Gaza-bound flotilla ‘set on fire’ following drone attack, crew say
Incident update 🔽
— London Ambulance Service (@Ldn_Ambulance) September 8, 2025
We were called at 4.50pm today (Monday 8) to Terminal 4 at Heathrow airport. We sent ambulance crews, our cycle response unit, an incident response officer, and our hazardous area response team (HART). We treated 21 patients before taking one to hospital. pic.twitter.com/v1NFt8oSd9
"Specialist officers attended the scene alongside the London Fire Brigade and London Ambulance Service and conducted a thorough search of the area.
"No trace of any adverse substance was found.
"Around 20 people reported an injury. None were deemed to be life-threatening or life-changing.
"Enquiries are ongoing."At 8.27pm, the airport said on X that emergency services had confirmed the terminal was "safe to reopen" and it was doing "everything we can to ensure flights depart as planned today".
The LFB said it was in the process of standing down its response, and that the cause of the incident remained under investigation.
Earlier on Monday evening, the airport had advised passengers not to travel to Terminal 4, while National Rail Enquiries said trains were unable to call at the terminal because of the incident.
The LFB said it was first called about the incident at 5.01pm and crews from Feltham, Heathrow, Wembley and surrounding fire stations had attended.
Transport Secretary Heidi Alexander said she was monitoring updates from those at the scene and the airport.
According to the airport's website, flights from the Terminal 4 were largely unaffected - with only a few delays expected.
Footage posted on social media showed passengers with their luggage waiting outside the airport, with some wrapped in foil blankets.
