ABOUT 20 times the recommended fluoride was accidentally added to Brisbane water supplies two weeks ago.
Premier Anna Bligh today said the first breach of safety guidelines had occurred between 9am and midday on Friday May 1.
The water should have had 1.5 milligrams per litre of fluoride but test results released this week showed it had between 30 and 31 milligrams per litre.
About 300,000 litres of water was released from a fluoride treatment plant at North Pine Dam.
The water flowed into as many as 4000 households in Brendale and Warner on Brisbane’s northside.
Ms Bligh, who was alerted to the issue last night, today moved to reassure people, saying there was a very remote chance of any health issues, particularly given symptoms would have emerged by now .
Queensland Health has not received any reports of ill-effects.
The effects of a fluoride overdose are symptoms similar to gastro enteritis.
Ms Bligh said she was angry about the bungle and has ordered a full investigation.
“While I am very concerned about this incident, it does not concern me in relation to the benefits of fluoride in our drinking system,” she said.
“Our plants treat our water for a range of safety purposes, so I want to understand what happened in this case.
“But it does not for one minute shake my confidence that fluoride is one of the most significant public health leaps forward of the last century.”
Ms Bligh said the incident was unprecedented at any other fluoride treatment plant in Australia.
“There will be a thorough investigation of this issue,” she said.
There are at least three safety checks which are believed to have failed.
The bungle is believed to have occurred during a routine shutdown for maintenance at the plant.
Operations shut down but the fluoride pump didn’t.
It effectively overdosed an amount of water which was released into the pipes when the plant resumed operations.
Chief health officer Dr Jeannette Young said the amount of fluoride that passed through the pipes over a three hour period was “of no health concern at all”.
“I”m confident the risk of anyone having suffered any adverse health outcome is remote – if indeed not zero,” she said.
Dr Young said for there to be a health risk the levels would have to be much higher and for much longer than three hours.
“It’s a high level in terms of what’s provided in the water but it’s a low level in terms of any risk,” she said.
Ms Bligh said Mark Pascoe, CEO of the International Water Centre based in Brisbane, will run the investigation.
“As an immediate precaution when any water treatment plants are shut down for normal maintenance, there will be a manual shutdown of the fluoride dosing equipment,” she said.