The ground-breaking research suggests that people living within a 20m "shadow" of high-voltage lines are three times as likely to suffer from asthma and twice as likely to have major depression. Researchers believe the danger levels drop rapidly outside that 20m-zone.

HIGH RISK: The new study suggests health risks for people living within 20m of high-voltage lines like these in West Auckland.

Although less than 1 per cent of New Zealanders live near the lines the research has implications to the vast number of people exposed to electromagnetic fields at work. For example, industrial sewing machine operators, welders and some supermarket check-out operators are subjected to prolonged magnetic field exposure. But although the evidence linking electromagnetic fields health problems mounts, scientists are yet to prove the link. The research is expected stimulate worldwide debate when it is presented to an international symposium on electricity and magnetism in Italy next month. The study will also be published in the official journal on biological effects of electromagnetic fields.

An Auckland University academic involved in the research Professor Ivan Beale, said the negative health effects of living close to high tension power lines were more widespread than. previous studies had shown. Some 570 people in South Auckland, West Auckland and the eastern suburbs took part in the three-year study. The participants consented to detailed measurements of magnetic fields being taken in their homes, to releasing their medical records and giving blood samples.

The study into the effect the power lines had on the nervous and immune systems revealed that adverse health effects became apparent in homes with magnetic field readings as low as 5 milligauss or mG. (the reading is obtained by measuring the density of the magnetic field with a hand held device.) One home recorded a 190mG reading.

Professor Beale, of the university's psychology department, said the research findings added weight to other studies which suggested he internationally accepted electromagnetic field exposure limits , should be lowered. The National Radiation Laboratory recommends 1000mG as a safe level, based on the guidelines. Houses close to high-voltage lines, which already sell more cheaply because of the lines, could be under further price pressure as the result of the research.

"Personally, I would not want to live underneath these power lines"

I would want to move as soon as possible,

not because I'm certain I would be affected adversely but I would not want to live with the doubts," Professor Beale said.

While research continued, Professor Beale. advised people to adopt a cautionary approach by avoiding magnetic fields where possible. He likened it to earlier this century when agents like tobacco and asbestos were suspected of causing harm -but it was many years before there was conclusive proof..