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A group of international experts say there is no concrete evidence to suggest a series of giant pylons through the Waikato to South Auckland is likely to cause sicknesses including depression, insomnia and a range ofcancers.
But a staunch opponent of Transpower's pylon project argues that there is alternative research linking the transmission lines to severe illnesses such as childhood leukaemia.
The Resource Management Act Board of Inquiry in Hamilton continued its hearing into Transpower's proposed $683 million 400KV electricity transmission line from Whakamaru to South Auckland yesterday.
The national grid operator has called in local and overseas experts from the Netherlands and Australia, who have presented evidence showing the project was unlikely to cause any adverse health effects.
Radiobiologist Eric van Rongen, who writes scientific literature on electromagnetic fields and health for the Netherlands Government, said many studies researching the links between extremely low frequency (ELF) magnetic field exposure and illnesses including depression, suicide, insomnia and effects on the immune system had been completed.
"For most of them, the evidence is inadequate to draw any firm conclusions."
Mr van Rongen said earlier research which found that long-term exposure to ELF magnetic fields saw a doubling of the childhood leukaemia risk had not been supported by more than 1000 epidemiological studies since.
His view was supported by biophysicist Andrew Wood, a professor at the Brain Sciences Institute at Swinburne University of Technology in Melbourne. Professor Wood said literature on the effects of electromagnetic fields on biological tissue was vast.
"Of those that have been studied, the outcomes have been inconsistent," he said.
"They have been so lacking in coherence that laboratory data were classified as 'inadequate'."
He said that because of the variability in studies, it had been possible to present an "apparently coherent case" for ELF being the cause of major illnesses including childhood leukaemia.
Bob McQueen, vice-chairman of the pylons' main opposition group, New Era Energy, said he had research showing there were associated effects from pylons including childhood leukaemia and miscarriage.
He said these illnesses had been recorded at homes exposed to pylons where electromagnetic field readings were 0.4 microteslas, well below the Ministry of Health's accepted standard of 100 microteslas for EMF transmission.
"These guys are saying 100 microteslas is okay, but they're talking 250 times higher than the levels at which these epidemiological studies show there is an effect," he said.
"It's kind of like back in the old smoking days when the tobacco companies would roll their scientists in and say, 'Oh yeah, no problem, there might be a little throat irritation'."
National Radiation Laboratory group manager Jim Turnbull said exposure to electric and magnetic fields from the 60m pylons was likely to be at levels similar to those found in home appliances such as vacuum cleaners or food processors.
He said the laboratory's calculations, taken 1m below the 400KV line, showed the electric field strength was 4.7 KV a metre while the magnetic field strength was 36 microteslas.
