A man has been arrested following a suspected hazardous materials incident at Terminal 4 of London's Heathrow Airport, police and local media reported Tuesday.

The Terminal's check-in area was evacuated and closed Monday evening after reports of possible hazardous substances. Metropolitan Police officers recovered a canister believed to contain CS spray, a substance that can cause eye irritation, chest tightness, coughing, and sneezing.

"It is thought that this substance caused a reaction to those within the airport," police said in a statement.

A 57-year-old man was arrested on suspicion of possession of a firearm -- namely CS spray -- and causing a public nuisance, according to the police.

The airport reopened shortly afterward.

Heathrow Airport is the primary and largest international airport serving London. According to its official website, over 67 million passengers travel through the airport annually on services offered by 90 airlines, travelling to over 180 destinations in over 90 countries.