Terminal 4 at London's Heathrow Airport reopened on the evening of the 8th.
Earlier that day, the terminal was closed and evacuated due to a "potentially hazardous materials incident"; however, other terminals continued operating normally.
Heathrow Airport stated on social media that emergency services have confirmed Terminal 4 can reopen.
The London Metropolitan Police issued a statement indicating no harmful substances were found at the airport.
As the largest airport in the UK, Heathrow was paralyzed on March 21 this year due to a fire at a nearby substation. According to British media reports, the incident affected more than 1,300 flights and disrupted the travel plans of about 250,000 passengers.