The cause of a chemical leak in a north Norfolk holiday park swimming pool is being investigated by officials.
Three young children taken to hospital as a result of the leak have returned to Woodland Holiday Park in Trimingham and the pool was reopened hours later.
North Norfolk District Council will now look into the incident according to the Health and Safety at Work Act 1974.
The chemical leak happened on Monday during routine maintenance. Emergency services were called and the swimming pool was evacuated, with three children taken to the Norfolk and Norwich University Hospital.
A spokesman for North Norfolk District Council said they were notified of the incident by the Health and Safety Executive.
She said: 'We will conduct an investigation to identify the cause. Based on the findings we will make any recommendations or necessary action to be taken.'
Andrew Hird, chief executive at the park who said the incident was due to a vapour leak, said the children were out of hospital.
He said: 'They are back on holiday. It is all sorted now and there are no problems.'
Three children, about ages two, five and nine had been taken to hospital and a family of three were also treated and made their own way to hospital.
Three ambulances, a rapid response car and a paramedic officer had been dispatched.
Paramedic officer, Lee Fox said: 'There were patients who were coughing, and complaining of sore throats and stomach aches.'
In October 2012, 10 people were treated after a chlorine leak at the park and a man in his 60s was taken to hospital as a precaution.
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