Queensland Premier Anna Bligh admits a bungle that released too much fluoride into Brisbane’s drinking water supply is embarrassing.

About 4,000 homes in Warner and Brendale, in Brisbane’s north, were thought to have received up to 20 times the allowable fluoride dose.

But new information by an independent expert found only a YMCA camp, and possibly about 400 homes in the suburb of Joyner, near the North Pine water treatment plant, were affected on April 30.

It is the second blunder the government has made over the incident, after first telling the public the wrong date.

Queensland Premier Anna Bligh described it as a highly unusual error.

“That I am putting out this information, even though it might be embarrassing, is evidence I am determined to put out every information when I get it,” Ms Bligh told ABC Radio on Friday.

Chief health officer Dr Jeannette Young said 211 school children who were at the YMCA camp at the time of the overdose had not displayed any symptoms of illness.

“Those children have not had any effects from that dose of fluoride they possibly received,” Dr Young said.

“It would need to be a lot, lot higher than any dose that’s being told to me (to cause illness).”

She also ruled out fluoride as the cause of an outbreak of blisters on a young girl, whose father called a Brisbane radio station on Friday, linking the two.

Opposition leader John-Paul Langbroek, who supports water fluoridation, said he was disturbed by the disarray of the government after the errors.

“(Fluoride) is a great public health benefit but it needs to be done properly,” Mr Langbroek said.

“If we need to get independent experts to sort out the mess that has been created it clearly shows the government has bungled this.”

The incident has only given anti-fluoride campaigners more ammunition.

Queenslanders for Safe Water spokeswoman Merilyn Haines said it proved the government was putting Queenslander’s lives at risk.

“This is one of the things that we were warning about – human error, accidents, and malfunctions,” Ms Haines said.

“It’s the same equipment, the same training, same staff and same procedures at all the plants so this could happen anywhere and it could happen again.”

Australian Dental Association Queensland (ADAQ) president Greg Moore said the error was regrettable but no reason for water fluoridation not to be rolled out.

“It’s a lesson for the water suppliers. There is a technical problem that has happened in a water treatment works and it’s next to unheard of in the rest of Australia,” Dr Moore said.

“We need process in place now so that the water-consuming public can be confident it doesn’t happen again.”