Current Risks - health hazards of electromagnetic fields and how to reduce exposure to them - Brief Article

Sierra, May, 1999 by Liza Gross

Experts finally link electromagnetic fields and cancer

For 20 years, scientists have been trying to determine whether a mainstay of modern life might be increasing your risk of cancer. Finally, last June, a panel convened by the National Institute of Environmental Health Sciences decided there was enough evidence to consider the invisible waves called electromagnetic fields, like those generated by power lines and electric appliances, a "possible human carcinogen." Yet with no federal funds on the horizon, the NIEHS is pulling the plug on more research. "What is outrageous," says Louis Slesin, a member of the NIEHS panel and the editor of the health newsletter Microwave News, "is that here you have a blue ribbon panel saying there's a problem, and then the NIEHS says, `Okay, we're closing up shop.'"

Electromagnetic fields, or EMFs, are all around us. Whenever you operate anything that runs on electricity, you're setting an electric charge in motion, creating a magnetic field. Imagine throwing a pebble into a pond and watching the water ripple out from the center. That's how a magnetic field fans out from its source, penetrating nearly everything in its path.

Before we inundated the planet with googols of radiating gadgets, the only electromagnetic phenomena we were exposed to came from the forces of nature, from gamma rays and sunlight to the magnetic field of the earth. Scientists refer to the EMFs generated by electric power, which alternate 60 times per second, as "electric and magnetic fields" because at this extremely low frequency the two fields can be studied separately. Until humans harnessed electricity, we'd never experienced these alternating fields at significant levels. And that's what worries some scientists.

Alternating magnetic fields--unlike the static EMFs generated by the earth--can routinely induce currents in your body Scientists have observed a variety of biological effects from exposure to EMFs, including changes in the rate cells manufacture hormones, enzymes, and other proteins, and in the way cells communicate with each other. Although little is understood about just how these ubiquitous fields may cause cancer, some experts have argued for years that they do.

Responding to public concerns, in 1992 Congress mandated an investigation of the health effects of electromagnetic fields. Near the end of the program, the NIEHS gathered experts in physics, medicine, and engineering to review the data linking EMF exposure to cancer risk. The panel pored over studies showing high rates of leukemia among children living near high-voltage power lines and of lymphoma among electric-utility workers and others exposed to EMFs on the job, and was convinced by the evidence.

Although skeptics still argue that the data is inconclusive, nearly ten years ago the EPA reached the same decision. "Anyone familiar with this data knows it points to a cancer risk," says Slesin. "But until we do more research, until we understand the biological agent and the mechanism, we can't characterize the magnitude of the risk."

While several epidemiological studies found a higher cancer risk among groups exposed to EMF levels above 2 milligauss (mG, the measure of magnetic field intensity) for extended periods, the panel concluded there's not enough evidence to pinpoint a safety threshold. That's because scientists aren't sure whether the potential danger of an EMF is a function simply of its strength, or whether other factors, such as the number of sudden changes in intensity, are also significant.

Many household objects emit far stronger fields than 2 mG: electric mixers and can openers, for example, can generate EMFs exceeding 600 mG at six inches. A typical home has a background level ranging from 0.5 to 4 mG. (Background EMF levels are generated by power lines, household wiring, and grounding techniques.) To find out the level in your house, call your power company. Most will measure it for free and recommend ways to reduce EMF emissions if necessary.

No one on the panel is suggesting that consumers eschew all things electric and return to the Dark Ages. Because the strength of a field drops off so dramatically with distance, protecting yourself can be as simple as taking a few steps back from a source. The key, says Indira Nair, associate professor of engineering and public policy at Carnegie Mellon, is exercising what she calls prudent avoidance. "Until we know more," she says, "avoid fields whenever you can."

Think about where you spend the most time and what you use that runs on electricity. Sit at least four feet from the TV and 18 inches from your computer screen. Many kitchen appliances emit very strong fields, so don't run them on full blast all at once. While you're not likely to use blow-dryers and electric shavers for extended periods, they expose your head and face to very strong localized fields of over 600 mG.

The bedroom merits particular attention. Keep motor-powered devices like electric clocks, radios, fans, and space heaters at least four feet from your bed. (Because EMF intensity varies with product design, a small motor-driven clock can generate a stronger field than a high-powered transformer.) If your bed flanks a wall, make sure there's not an electric appliance on the other side. And ditch the electric blanket. Though redesigned models emit a much weaker magnetic field, a University of Utah study found that the new blankets induce higher currents in your body.