News

Electromagnetic fields may be carcinogenic

Terri Rutter, Boston

Electromagnetic fields, like those surrounding electric power lines, should be regarded as "a possible human carcinogen" a working group drawn together by the US National Institute of Environmental Health Sciences reported this week.

The group of scientists and industry experts had been meeting in Minnesota to review the scientific evidence over whether electromagnetic fields cause cancer. A panel vote of 19 to 9 supported the report.

"This report does not suggest that the risk is high," said the chairman, Michael Gallo, in a statement released by the institute. "It is probably quite small, compared to many other public health risks. However, I strongly believe that additional hypothesis-driven, focused research should be pursued to reduce uncertainties in this arena."

The working group found no connection between electromagnetic fields and Alzheimer's disease, depression, or birth defects, and no increased risk of abortion caused by video display terminals.

In 1979 a group of researchers in Denver, Colorado, published the results of a study that found an association between a group of children who had died of leukaemia and the children's residential proximity to high current electrical transmission or distribution lines. Since then, numerous epidemiological studies have looked for similar associations, but with inconsistent findings. Biological studies on animals have found little or no evidence linking disease to exposure to electromagnetic fields.

Meanwhile, however, the public has also been concerned, and in 1992, Congress voted to accelerate research in this area. It launched the EMF/RAPID programme, under which $23m (£14m) in government funding has been matched by funding from industry.

In 1997 a committee of the National Academy of Scientists also reviewed the scientific evidence surrounding electromagnetic fields and their association with cancer. According to Professor Jerry Williams, who sat on both working parties, the academy's group found "no convincing evidence" to support an association between electromagnetic fields and an increase in cancer.

"Hundreds of people have looked and have never found a big enough response," said Professor Williams, who is professor of oncology and director of radiobiology at Johns Hopkins Medical Institution. Professor Williams was one of the nine who voted against the working group's report. He has filed a minority report, which will be available with the working group's full report at the end of July (http://www.niehs.nih.gov/emfrapid/ home.htm).

Dan Wurtenburg, an epidemiologist who also sat on both the academy's committee and the national institute's working group, disagrees. He argues that both reports say there is a possible association between electromagnetic fields and disease that needs to be further investigated.

The group presented its findings to the institute's director, Kenneth Olden, who will hold a two month consultation period before making his recommendation to Congress.