About 80 visitors and staff were in the centre

Lanarkshire ambulance control said a "major incident" was declared at about 0900 BST, with police, fire and ambulance crews called to the leisure centre.

Dozens of adults and children were evacuated from the pool wearing just their swimming costumes.

Thirty two people, including three children, were taken to Monklands Hospital.

One victim was taken to Hairmyres Hospital in East Kilbride and 15 to Wishaw Hospital.

Nineteen people remained in hospital on Thursday night, with two under close supervision.

Most of the injured people are expected to be released on Friday.

The leak occurred as a delivery of sodium hypochlorite was made to the leisure centre on Thursday morning.

We know there has been a realease of chlorine gas.

Strathclyde Fire Brigade spokesman

A spokesman for Albion Chemicals said the chemicals are used for the chlorination treatment of the pool's water.

He said: "Fumes were emitted from the receiving tank and the leisure centre was evacuated. The emergency services were contacted and attended the scene."

Alex Guild, whose home looks onto the Time Capsule, said: "I saw the fire engines and ambulance arriving and then I saw people running out of the Time Capsule.

"Then the helicopter arrived and they started to run out the helicopter with two stretchers.

"They immediately ran into the Time Capsule. There were more people coming past them and running out.

"Some were quite upset, just wearing their costumes. "

Area declared safe

A spokesman for Strathclyde Fire Brigade said: "We know there has been a realease of chlorine gas.

"Exactly what the cause has been will only be known after a full investigation."

Firefighters in breathing apparatus have been inside the leisure centre to neutralise the sodium hypochlorite.

Ambulance crews had to work flat out

Police, who had been advising residents in nearby houses to stay indoors and keep their windows closed, later declared the area safe.

Councillor Jim McCabe, leader of North Lanarkshire Council, said the incident would be fully investigated by the Health and Safety Executive.

He said: "There has never been anything like this happen at the centre before.

"At the present time the Health and Safety Executive will carry out a full investigation into the incident and until they have completed that I am not prepared to speculate on what the cause may have been."

Mr McCabe said the chemical contractor used by the council was "very reputable" and was used, he understood, by many local authorities in Scotland.