Emergency services including police, fire and ambulance crews were called at around 2.35pm to Wild Duck Holiday Park in Belton near Great Yarmouth, Norfolk.
Haven Holidays spokesman Tom Cassidy said that 33 people described as ‘walking wounded’ had been evacuated and taken to three different hospitals as a ‘precaution’.
The casualties taken to Norfolk and Norwich Hospital, James Paget Hospital in Great Yarmouth or Ipswich Hospital, Mr Cassidy said.
‘Thirty-three people have been taken to three local hospitals as a precaution. They include one three-year-old child and a member of staff.
‘The casualties have been described to me as walking wounded.
‘Obviously the park is now in lockdown while they try and source the chemical leak.’
A Norfolk Constabulary spokesperson added: ‘It is believed there are around 40 casualties who are being treated by ambulance crews.
‘The immediate area has been evacuated and a 20 metre cordon has been put in place around the building whilst emergency services deal with the incident.’
The alarm was raised after reports of swimmers suffering stinging to their eyes.
The holiday park which is run by Haven is set in 98 acres of woodland and has indoor and outdoor pools.
