Nearly 50 people, the majority children, have been treated by paramedics after a chlorine gas leak at a Black Country swimming pool.

Eleven people were taken to hospital and others treated at the scene following the incident at Coseley Swimming Pool on Wednesday.

West Midlands Ambulance, police and fire brigade were called to the pool in Pear Tree Lane, just after 1pm, after swimmers, some of them as young as eight, complained of watery eyes, difficulty in breathing and throat and nose irritation.

Those affected were treated at the scene by staff from the Hazardous Area Response Team before they were transferred to New Cross, Sandwell and Russells Hall hospitals.

The swimming baths, which has been earmarked for closure, was particularly busy as it had offered free sessions to children for the Easter holiday break.

Assistant Chief Ambulance Officer, Daniel Gore, who led the ambulance service response, said: “There appears to have been a release of a chlorine based chemical at the swimming pool.

“We have treated a total of 48 people; many of them were children, one of whom was as young as eight. They were displaying symptoms of watering eyes, difficulty in breathing and throat and nose irritation.

“A number of the casualties had come out of the building in their swimming costumes. They were given thermal blankets to keep warm.

“After we had got the most seriously affected off to hospital we set up an area where the doctors and ambulance staff could assess each of the other casualties.

“We then transported those that needed further assessment or treatment to one of three hospitals; New Cross, Sandwell and Russells Hall.

“A further 16 were treated and discharged at the scene by the doctors. Approximately half were kept at the scene until their parents could come and collect them.”

People living within 400m of the swimming pool were also advised to keep all windows and doors closed while the incident took place.

A spokesman for the Health Protection Agency said: “Minor exposures to chlorine may include irritation of the nose and throat and stinging or redness in the eyes.

“More substantial exposure may cause coughing or breathing difficulties. Those with a chest condition such as asthma or emphysema may be more sensitive to the effects of chlorine.

“Less commonly, symptoms may not occur immediately but after some hours. Therefore, exposed individuals who have not developed symptoms or who have recovered from initially mild symptoms, should be told to seek medical advice if they develop respiratory problems at any time over the next 48 hours.

“Most people who have developed symptoms following exposure to chlorine will not suffer any long-term effects. A one-off exposure, sufficient to cause mild lung or eye irritation, is unlikely to result in long-term health effects.”

West Midlands Fire crews sent specialist chemical officers to monitor levels of chlorine gas at the pool.

The officers used fans to ventilate the building and levels were returning to normal by the evening. It is thought many people may have left the swimming pool before the symptoms started.