Several people have been taken ill after a mystery chemical incident saw a Heathrow Airport terminal evacuated. 

A ‘possible hazardous materials incident’ led to the shutdown of Terminal 4 shortly after 5pm on Monday, resulting in crowds gathering outside the terminal as ambulances and fire crews arrived at the scene.

Mutltipe people were taken ill at the airport but no-one is in a life threatening condition, the Metropolitan Police confirmed. 

‘Firefighters are responding to a possible hazardous materials incident at Heathrow Airport,’ an airport spokesperson said. 

‘Specialist crews have been deployed to assess the situation, and Terminal 4 has been evacuated as a precaution while firefighters respond,’ they stated.

The London Fire Brigade mentioned: ‘Specialist crews have been deployed to evaluate the scene, and part of the airport has been evacuated as a precaution while firefighters are responding.

‘The brigade received the first call regarding the incident at 17:01, and crews from Feltham, Heathrow, Wembley, and surrounding fire stations have been dispatched to the scene.’

Those evacuated have been given bottles of water by airport staff while emergency foil blankets have been handed out to keep people warm. 

Emergency crews could be seen putting on protective white suits before entering the terminal. 

Emergency crews could be seen putting on protective white suits before entering the terminal

Crowds of people were seen gathering outside Terminal 4 as ambulances and fire crews rushed to the scene

A terminal at Heathrow Airport has been evacuated as emergency services respond to an ‘incident’

Witnesses reported seeing privacy screens being put up as passengers were evacuated around 150 metres from the terminal. 

Footage shows a staff member telling passengers he was unaware when they would be able to re-enter. 

Terminal 4 check-in has been shut but all other terminals are still open and operating as normal.

A Heathrow Airport spokesperson said: ‘Terminal 4 check-in has been closed and evacuated while emergency services respond to an incident.

‘We are advising passengers not to travel to Terminal 4 and are assisting those present. All other terminals are operating normally. We will provide further updates as soon as possible.’

National Rail said trains were not stopping at Heathrow Terminal 4 due to ’emergency services dealing with an incident’. 

Most flights still appear to be going ahead. The only delay reported is a Saudia airline flight to Jeddah, Saudi Arabia.

The London Ambulance Service said: ‘We were called at 4.50pm to reports of an incident in Terminal 4 at Heathrow airport. 

‘We have dispatched resources to the scene, including ambulance crews, our cycle response unit, an incident response officer, an advanced paramedic practitioner, and members of our hazardous area response team (HART).’

Crowds of people were seen gathering outside Terminal 4 after a ‘possible hazardous materials incident’

A Heathrow staff member told passenger that the airport terminal would be closing after an ‘incident’

Crowds of people waited outside the airport after Heathrow confirmed there was a ‘possible hazardous materials incident’

‘The incident is ongoing and we are working with our emergency services partners to respond safely to this emergency.’ 

Transport Secretary Heidi Alexander said she was monitoring updates from the aiport.

‘Emergency services are responding to an incident at Heathrow’s Terminal 4 which has prompted its evacuation,’ she wrote on X.

‘I’m monitoring updates from those on the scene, as well as Heathrow Airport itself.

‘Passengers should not travel to Terminal 4 until advised otherwise.’

In March, Heathrow Airport was shut after a devastating electrical fire which sparked worldwide travel chaos and days of disruption for hundreds of thousands.

The UK’s busiest airport was forced to close after its main electrical substation exploded and set alight less than two miles away in the west London suburb of Hayes.  

The closure impacted 270,000 journeys and was caused by ‘an unprecedented set of circumstances’, Heathrow chairman Lord Deighton said.

This is a breaking news story. More to follow.