KEY POINTS:
Health authorities are warning people potentially exposed to elevated levels of chlorine gas during a Sunday water polo competition to watch out for poisoning symptoms after 11 needed hospital treatment.
"Symptoms can be delayed for up to two days after exposure," an Auckland medical officer of health, Dr Denise Barnfather, said yesterday.
"Any children who experience wheeze, cough, shortness of breath, sore throat or chest pain on inhalation associated with the pools need to see a doctor immediately."
The West Wave Aquatic Centre in West Auckland was closed yesterday after a number of the teenage players developed breathing difficulties.
Its pools were shock-dosed with chlorine last week after some players were linked to a diarrhoea bug.
At the weekend the chlorine levels were 25 to 29 per cent higher than usual but were just below the usual range last night.
The pool was given the all-clear last night after air testing showed chlorine gas levels within acceptable limits.
The reason for players in Sunday's competition becoming sick is unclear, but pool and Waitakere City Council officials believe it may have been caused by a build-up of gas from the higher-than-usual chlorine levels.
"There may have been elevated levels of chlorine in the air immediately above the water, where the players were taking their breaths," said council public affairs manager Dai Bindoff. "Because they were playing hard, they may have been breathing enough of this extra chlorine to make them sick."
Some of the 11 players admitted to hospitals from North Shore to Waikato on Sunday or early yesterday were still there later in the day; others had been discharged after receiving treatment including oxygen, steroids and Ventolin. A 7-year-old girl not involved in the competition also received medical attention.
Sam Haysom, 14, of Ponsonby, was taken by ambulance from his doctor's clinic to Starship hospital, where he spent the night.
He said the attack of breathing difficulties was "quite frightening". It came on after he had got out of the pool, receded after treatment at the clinic, then came on again at home, forcing him back to the clinic and then hospital.
He was feeling better yesterday and expected to be well enough to compete in the national championships in Wellington from Thursday, "but I don't know about some of the other players".
His father, Trevor Haysom, said Sam had asthma when younger. "He hasn't had attacks of this nature for quite a number of years. It's probably the worst attack he's ever had."
Team-mate Rory Clarke, 14, of Pt Chevalier, was still coughing and experiencing tightness in the chest yesterday.
"Walking home from school [Western Springs College] I could feel my chest tightening without the [Ventolin] inhaler and I used it a lot. I'm not asthmatic. I've probably used it 10 times."
The aquatic centre has had chlorine problems since a $14 million redevelopment completed in 2002. A chlorine leak a fortnight after the re-opening led to 39 people being taken to hospital, where they were discharged within hours. A second leak developed in 2003.
All nine pools were given high doses of chlorine dioxide last week to kill cryptosporidium, a micro-organism which can cause diarrhoea if swallowed.
Eight confirmed cases of the infection and five probable cases in October and November have been linked to the centre and another person has been infected through one of the initial cases - 14 people in all.
Several of the pools were linked to the cases, but not the pool in which the water polo competition was held.
It was shock-dosed on Friday and kept shut for 24 hours.
