A number of casualties with breathing difficulties were treated by London's ambulance service on Wednesday after a leak of a high quantity of chlorine gas at the Queen Elizabeth Olympic Park's aquatics centre, emergency services said.
The London Fire Brigade said that around 200 people had been evacuated after it was called at around 9:45 GMT to the east London park, which hosted Summer Olympics events ten years ago.
"Due to a chemical reaction a high quantity of chlorine gas was released. London Ambulance Service are treating a number of patients," London Fire Brigade said in a statement.
The London Ambulance Service described it as a major incident, and said it had sent multiple resources to the scene.