Five people were taken to hospital today after inhaling chlorine following a chemical spillage.

The incident happened at soft drinks maker Histogram, on Belmont Industrial Estate, near Durham, just before 11am, when around 1000 litres of hypocleanse, a type of bleach, was released by a faulty valve.

It came into contact with citric acid, and the two substances reacted to produce chlorine gas.

Staff called the fire brigade, and three employees and two drivers were taken to the University Hospital of North Durham as a precaution, after coming into contact with the irritant.

The factory, which employs 71 staff, was evacuated, but production continued uninterrupted.

Community Fire Safety Officer David Turnbull said the incident could have been much worse. "Chlorine affects the sinuses and any other parts of the body that are water-based," he said.

"It gets into the eyes and you can't see. This could have been far more serious than it was, but the company called the fire brigade at an early stage.

"We used standard methods to clear up the spillage, and were at the premises for about an hour."

The Environment Agency, water authority, and Health and Safety Executive were informed, and an investigation into the incident is underway.