Concerns have been raised over the safety of mobile phone masts as education minister David Blunkett orders an "urgent" inquiry into the siting of the masts in schools. Mobile phone companies pay up to £10,000 to schools which allow the masts to be set up on their premises. More than 500 schools in the UK have taken advantage of the cash injection, so far. But this is not the familiar "mobile phones fries your brains and gives you cancer" bandwagon. Dr Hyland, a physicist at Warwick University, who raised the alarm is not concerned with the heating effect of the microwaves, but the possibility of resonance between the external radiation from the masts, and the brain's own frequencies. "Living organisms are all a bit like radio receivers, and you can get resonance between external radiation and living things if the radiation matches natural frequencies," he said. "The microwaves from base stations are transmitted in pulses and it is the frequency of these slower pulses that is in the range of alpha brain waves. These brain waves are not stabilised in children and there could be an unexpected adverse effect." Dr Hyland stressed that there was no evidence to support his concerns. But he also pointed to the lack of any risk assessment of the effect of microwave pulses on children. Without such quantification "(masts should not be sited anywhere near schools," he said. The National Radiological Protection Board, which is responsible for reviewing all scientific literature on radiation, said the mast sites do not represent a threat to health. In official statements the board only addressed the heating effect of microwaves, and no one could be reached for further comment on the issues raised by Dr Hyland. "The radio waves produced by the transmitters are sufficiently weak that the exposure would only exceed recommended levels if a person were to approach to within a few meters directly in front of the antennae." The board also pointed out that radio waves do not have enough energy to damage cell DNA, so we really don't need to worry about developing brain tumours. The board does say that there is still a need for further research into other concerns over the safety of microwave radiation. ®