One mother, who had taken her children to the centre on Thursday afternoon, said: “As we pulled in, we parked and got out and there was a little boy really coughing outside the swimming pool, we thought ‘goodness me’.
“We walked up to the entrance and there was another man coughing.
“We stood in a long queue and started to think there was something wrong, as there were lots of lifeguards around and people coughing and spluttering.
“We got to the front of the queue and they said we’re evacuating, and only at that point did they sound the siren.”
Outside, towels were being handed out and after the fire brigade arrived crews started to give oxygen to people, she added.
“We saw streams of people coming out of the swimming pool, just in their swimming costumes,” she said. “Thank goodness it’s a warm day.
“Our eyes were stinging a little bit. There were lots of police cars and fire engines arriving, we just hope everyone’s OK.”