A “possible hazardous materials incident” triggered the evacuation of Terminal 4 at London’s Heathrow Airport, one of the world’s busiest air travel hubs. Emergency services responded to reports of a potential hazard, leading to the closure of the check-in area and advising passengers against traveling to the terminal in west London. Dozens of flights faced delays as crews assessed the situation, with around 20 individuals reporting injuries—none life-threatening—after being evaluated by paramedics.

Specialist firefighters and police officers were deployed to inspect the site, with part of the terminal evacuated as a precaution. A London Fire Brigade spokesperson confirmed that “specialist crews have been deployed to carry out an assessment of the scene,” while Heathrow Airport officials stated the area was closed “while emergency services respond to an incident.” Despite initial disruptions, flights at other terminals continued without significant issues.

By late evening, Heathrow announced Terminal 4 had reopened after safety checks, with firefighters “standing down” their response. The Metropolitan Police confirmed no traces of hazardous substances were found, and paramedics treated 21 patients, one of whom was hospitalized. While the cause of the incident remains under investigation, authorities emphasized passenger safety as a priority. Unverified footage showed crowds gathered outside the terminal, though departures continued as scheduled.