Police have arrested a man on suspicion of bringing teargas into Heathrow airport, which caused Terminal 4’s check-in area to briefly shut down.
The check-in area at the UK’s main international airport was evacuated for around three hours on Monday evening as emergency services probed a “potential hazardous materials incident”.
A Metropolitan police spokesperson said a 57-year-old man had been arrested after urgent inquiries on suspicion of possession of a firearm (CS spray) and “causing a public nuisance”.
After searching the area, Met officers located a canister of “what is believed to be CS spray”, which was “thought to have caused a reaction to those within the airport,” the police said.
Police said about 20 people reported symptoms of irritation and were treated by paramedics, but the spray “did not cause any life-changing/threatening injuries”.
CS spray is a riot control agent, also known as teargas, which can cause a burning sensation to the eyes, throat, lungs and skin.
The man remains in police custody and the incident is not being treated as terrorism-related.
A source in the Met Police initially suspected that the incident could have been a case of “mass hysteria” before the canister was located, after officers scoured the area and were unable to find the source of the hazardous substance passengers had reported.
Police were called to the airport shortly before 5pm, but the airport reopened at 8.30pm and said it was doing “everything we can to ensure flights depart as planned today”. According to the airport’s website, flights from Terminal 4 were largely unaffected, with only a few delays expected.