TORONTO - A school board in central Ontario is defending its decision to keep wireless Internet access in classrooms, despite fears from some parents that radiation from Wi-Fi transmissions is making kids sick.

There is no scientific or medical evidence to show children complaining about headaches, dizziness and nausea are being made ill by the Wi-Fi in their classrooms, the Simcoe County District School Board said Monday.

The board will not turn off Wi-Fi access in schools this fall, despite the concerns of critics who say there's no evidence to prove radiation from wireless transmitters is safe for children as young as four.

There's no evidence to show Wi-Fi harms children, said the board's director of education, John Dance.

"There's been a lot of information, but there's nothing definitive that says wireless is causing the issues, so the board affirmed its decision for wireless communications in our schools," he said.

"There's been nothing to this point along the lines of medical evidence to say that any illnesses or whatever have been caused by wireless communications."

A group of parents formed the Simcoe County Safe School Committee when they say they realized their children were displaying the same sorts of symptoms, and that the problems cleared up on weekends and holidays when kids weren't in school, said organizer Rodney Palmer.

They found parents reporting similar problems among kids at 14 different schools in the region, about an hour's drive north of Toronto, and tried unsuccessfully to convince the board to turn off the Wi-Fi and go back to hard-wired connections for Internet access.

"Parents are going to start pulling their children out of school," predicted Palmer. "I'm not putting my kids back into those schools. The health of children is not being cared for here."

The Simcoe school board has 50,000 students but only about a dozen parents came forward to the parents' group to complain about symptoms and to suggest the problem is the Wi-Fi, said Dance.

"We haven't had a single medical doctor come down on the side that a child's repeated headaches are coming from this," he said.

"We tend to err on the side of caution whenever we can, but ... this came up well after wireless had been installed in our schools."

The ministries of education and health both affirmed the board is doing the right thing by keeping wireless Internet access in its schools, added Dance.

Education Minister Leona Dombrowsky said Monday that she would write to her federal counterpart outlining the parent's concerns about Wi-Fi, saying Ottawa is in the best position to address the issue.

Professor Magda Havas of Trent University in Peterborough, Ont., who does research on the health effects of electromagnetic radiation, issued an open letter last year saying she was "increasingly concerned" about Wi-Fi and cellphone use at schools.

"It is irresponsible to introduce Wi-Fi microwave radiation into a school environment where young children and school employees spend hours each day," Havas wrote.

Statistics show young children absorb much more radiation than older children and adults because of their thinner skulls.

It is a public health issue, insisted Palmer, and should at least be taken as seriously as the threat of West Nile Virus.

"I can count in my school more victims of microwave radiation than all of Canada has from West Nile Virus," he said.