Thousands evacuated from Science Museum

Two thousand visitors and staff were evacuated from the Science Museum in London after a "chemical incident" yesterday. Three people were taken to hospital following what was believed to be a spillage in the basement.

A total of 22 people, all staff or contractors, were treated. Some complained of irritated eyes and sore throats, while others said they were suffering from sore chests. It is thought that some of those affected came into contact with an unknown substance before rubbing their eyes.

Emergency services were called after an alarm sounded at 11.30am. Specialist hazardous substance ambulance teams and firefighters in protective clothing were called to the South Kensington attraction to treat people and to try to identify the source of the irritation.

A London Ambulance Service spokesman confirmed they were called to reports of a chemical leak in the Science Museum at around 11:30am. "We sent four ambulance crews, five Hazardous Area Response Teams and a duty officer. Our staff treated 15 men and seven women," he said. "Three of the patients, two men and one woman were taken to Chelsea and Westminster Hospital with chest tightness and the rest of the patients were treated at the scene for eye irritation and sore throats." It is not believed their conditions were serious.

A total of 35 firefighters from London Fire Brigade attended. A team called to the scene failed to identify the chemical involved. However, police sources last night said they believed it was a household cleaning fluid, kept at the scene. A museum spokesman confirmed that the basement – where the spillage happened – contained galleries and staff rooms but was unable to say in which it had taken place.

Firefighters in protective clothing remained at the scene carrying out investigations until around 4pm yesterday. A London Fire Brigade spokesman said he was unsure if their failure to identify the substance was due to the museum's ventilation systems.

He said: "The readings do not suggest that any residue is still present. We took samples in the area and used them against charts to find out if they match any known chemicals. However, in this case, there was not enough residue left behind."

A cordon around the area was removed late yesterday afternoon and a museum spokesman said last night that he expected the attraction, which is popular with tourists and children, to reopen today.

A Science Museum spokesman said: "The safety of our visitors is paramount and we have worked closely with London Fire Brigade to assess the situation prior to making the decision to reopen. We are grateful to the London Fire Brigade, the Metropolitan Police and the London Ambulance Service for their assistance throughout this incident."

However, staff said yesterday that they had been given little information on what to do and had just been left standing. "An alarm went off at around 11.30 this morning and we were told to get out," one employee, who did not want to be named, said late yesterday afternoon. She added: "We weren't given any information; we just had to leave our belongings and go outside."

A museum spokesman said he did not know what instructions, if any, staff had been given. The museum's director, Prof Chris Rapley, refused to be interviewed about the incident.

Scotland Yard said the incident was not being treated as suspicious and a spokesman for the museum said it would reopen today as normal.