London Fire Brigade said around 200 people were evacuated after a “high quantity of chlorine gas” was discharged Park administrators said earlier that “there are a number of casualties with breathing difficulties" LONDON: A swimming pool at the London sports complex that hosted the 2012 Summer Olympics was evacuated Wednesday and ambulance crews treated a number of people after chlorine gas was released inside the facility, authorities said. The London Fire Brigade said around 200 people were evacuated after a “high quantity of chlorine gas” was discharged inside the Aquatics Center at the Queen Elizabeth Olympic Park in east London due to a “chemical reaction.” “While we ventilate the premises, we would ask those residents in the immediate vicinity to close their doors and windows,” the brigade said on Twitter. Park administrators said earlier that “there are a number of casualties with breathing difficulties” who were under the care of ambulance workers. Queen Elizabeth Olympic Park, which was built for and hosted the 2012 Olympic Games, first opened to the public in 2014. The Aquatics Center’s management said the chlorine gas release occurred “when the facilities management company that operates the plant room took delivery of pool chemicals.” The British capital’s ambulance service said it was responding to a “major incident” alongside firefighters and police. London Mayor Sadiq Khan said he was in close contact with emergency services and warned people to avoid the park. While the chlorine that is added to swimming pools to kill bacteria is safe, chlorine in gas form is highly toxic.