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
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
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
"The trouble with trying to reduce exposure is that we don't know which aspects
are biologically important," says Paul Gailey, EMF program manager at Oak Ridge
National Laboratory in Tennesee. "So you can easily design out one suspected
problem while creating another."
Until scientists better understand just how EMFs are creating damage, federal
safety standards will have to wait. With the NIEHS closing the door on more
research, the only new studies will be funded by industry-not exactly a
disinterested party. "We are continually increasing our use of electrical
equipment, filling our environment with EMFs," says Gailey. "It only makes sense
that we understand exactly what the consequences are."Liza Gross
Liza Gross is Sierra's copy editor.
Urge your senators and representative to support publicly funded EMF research.
For more information, visit the NIEHS Web site,