A healing centre worker has told of his horror when he realised he had mixed a cocktail of killer gas.

Within seconds of Christian Rowbotham's mistake, deadly chlorine gas poured in through air vents in the healing centre's pool where patients and the manager's children were swimming.

Luckily the swimmers were just getting out of the water as the highly toxic vapours filtered into the swimming pool at the Worth Healing centre in Long Causeway, Oxenhope.

Richard Atkinson, the manager of the centre, who was also in the pool area, immediately raised the alarm and alerted the emergency services.

An ambulance arrived and took his two sons - Thomas, 12, and Max, eight -to Bradford Royal Infirmary. They were later released after a routine check-up found no injuries.

Patients who had been using the pool were also examined and found to have received no side effects from exposure to the gas.

The lethal gas was created when Christian mistakenly mixed highly concentrated granular chlorine to a solution of weak hydrochloric acid in a small room next to the pool area. The solution began to bubble violently, and after a few seconds the reaction had started to give off deadly toxic chlorine gas.

Christian says: "I was going through the routine checks we do every day and I was just trying to adjust the pH level in the pool slightly.

"When I added the crystals to the solution of mild hydrochloric acid it turned yellow and started to bubble violently and produce a really strong gas.

"The two containers which the chemicals are stored in look almost identical and there is only a small difference on the label, so it is very difficult to tell the difference."

Mr Atkinson says: "I was in the pool with my sons and some of the pensioners we treat when we smelt the gas, and we knew instantly that something was wrong.

"The effects of the gas came on just like that - with incredible speed - and it was just luck that we were getting out of the pool at the time."

Illingworth Fire Station commander Graham Dean explains: "As soon as we identified what chemicals were involved we contacted the chemical company for information on how best to tackle the substance.

"We then neutralised the mixture by gradually diluting it. This weakened the substance and slowed down the reaction of chemicals."

Two firemen in special protective suits carried the container outside the building, and started to dilute the chemicals. Chlorine gas is a highly toxic substance which can cause blistering to the skin and throat on brief contact, and possible fatality if a person is exposed for any longer than a few minutes.

The firemen had to be shower-hosed off afterwards.

The healing centre, situated between Oxenhope and Denholme, has been open for more than two years, and provides treatment for people suffering any kind of illness.

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