Emergency services were called to Terminal 3 at the major airport at 8.11am this morning (December 7) with reports of people being assaulted.
Armed officers were also in attendance.
At the scene, a number of patients were located suffering injuries police believe are linked to substance like a form of pepper spray.
These injuries are not thought to be life threatening or changing.
A man was arrested on suspicion of assault, with police making enquiries to locate further suspects.
READ MORE: People in hospital after ‘substance sprayed in assault’ at Heathrow Airport
Cmndr Peter Stevens said: “At this stage, we believe the incident involved a group of people known to each other, with an argument escalating and resulting in a number of people being injured.
“We are not treating this incident as terrorism. I understand the public’s concerns and would like to thank those in the area for their cooperation this morning.”
Anyone with information about the incident is asked to call 101, quoting CAD 1803 7 DEC.
