Paramedics treated the casualties – five children and 14 adults – who were attending an adult and toddler swim session at the East Sands Leisure Centre in St Andrews, which was evacuated at around lunchtime.
The Scottish Fire and Rescue Service (SFRS) confirmed last night that the injured were being treated for “breathing irritation” following the incident at the centre on the town’s St Mary’s Street. Two members of staff were also taken to Ninewells Hospital in Dundee, along with the 19 affected, for further treatment, and a spokesperson for NHS Tayside later confirmed that “all of the patients had been exposed to chlorine gas”. Last night police and investigators remained at the scene attempting to trace the source of the leak.
Reports suggested the chemical was sodium hypochlorite, commonly used as a disinfectant, but the SFRS said tests had yet to be carried out.
Thirteen fire engines and 55 firefighters with breathing apparatus, along with ambulance crews and a decontamination team, were dispatched to the leisure centre, which also houses a spa, squash courts and a gym, shortly after the swimming session had ended.
It is understood that the spill occurred in a plant room beside the pool area. Sodium hypochlorite, which becomes bleach when dissolved in water, can cause breathing difficulties, burn the skin and damage eyes.
Allen Wilson, who is president of the Institute of Swimming Pool Engineers, said: “Sodium hypochlorite is a liquid form similar to bleach with up to 15 per cent active chlorine.
“If this substance is allowed to mix with an acid it will release chlorine gas. Chlorine gas can blind, cause long-term respiratory complaints or even kill.”
Last night one eyewitness said he heard a “big bang” and felt a stinging at the back of his throat.
Duncan Meekison, who was sitting in the spectator area, said his daughter and her friend were among those treated in hospital.
“There was an elderly woman next to me with two small children and we said it was time to get out,” he said. “The staff were brilliant. They set off the fire alarm and got us out. The emergency services were on hand very quickly.”
Sophie Watson, 29, who was at a gymnastics class with her son Alfie when the centre was evacuated, said: “We were told we had to get out and all sent out to the front of the building.
“Fire engines started turning up and we kept getting told to move further and further back.”
Local resident Robert Ovenstone, 46, added: “This is the first time I’ve seen anything like this. I saw men in big green bio suits and people brought out in their swimwear.”
Steven Smith, another eyewitness who was working nearby, described how he saw a group of children leave the centre.
“At first impressions, we thought it was just a school trip. It was only when we saw some children were getting attended to by an ambulance crew that we realised something might be wrong. ”
Other buildings in the area were also evacuated after the leak. But the Scottish rugby team, which was training at the nearby St Andrews University sports centre, was not affected.
A spokeswoman for Fife Sports and Leisure Trust, which operates the facility, said: “The exact cause of the incident is still being investigated by the emergency services and there is no threat to the surrounding area.”