The Fear of Weak Electromagnetic Fields

By Robert K. Adair, PhD

One need not be a physician to conclude that the collision of falling leaves with human heads cannot constitute a significant cause of fractured skulls. Only to someone who knew only that leaves are parts of trees might it seem even plausible that leaves break heads. But few of us understand magnetic fields as we do tree parts. Are the minute magnetic fields from our power distribution systems that some have associated with cancer leaves or tree-limbs? I answer, "They are metaphorically leaves, and it is no more possible that they cause cancer than that real leaves crack skulls."

Field Basics

Electric and magnetic fields act on matter through forces on electric charges. The fields can be significant biologically only if they change the energies of charged biological elements as much as the mean energy from thermal agitation, kT, where k is Boltzmann's constant and T is the absolute temperature (about 310 degrees Kelvin). The changing of magnetic fields happens primarily through the electric fields associated with that change (the Faraday effect). Electric fields alleged to be carcinogenic and generated in humans by the 60 Hz 5 milligauss (mG) magnetic fields from an electric power distribution system will be only about ten millionths of a volt per meter (V/m) and cannot induce an energy transfer to biologically significant molecules greater than one-millionth kT.

While there may be biological amplification mechanisms that we do not now understand, such mechanisms can work only if the "signal" is larger than the electrical noise -- and the body is electrically noisy. The fundamental random (Johnson-Nyquist) electric fields from the thermal agitation of charge, acting on cells, are thousands of times greater than the electric fields produced by the 5 mG fields of our environment. Hence the environmental fields cannot affect biology on the cell level.

Over larger regions, that thermodynamic noise is less important as the thermal fluctuations of the charge average out, but there are other endogenous sources of electrical noise. The familiar electric fields generated by heart action, measured in the course of an electrocardiogram, are more than a hundred times greater than the environmental fields. Even over the frequency band of about 60 Hz, the electric fields from the heart have been measured (by John Bergeron) to be about ten times greater than the electric fields from 5 mG 60 Hz magnetic fields.

A young woman appeared on television early in 1993 to express her conviction that the cancer found in her child was induced by power-line magnetic fields while the child was in utero. But the baby was subject to between ten and one hundred times stronger fields by her mother's heart action while her mother was carrying her.

Of course, large electric fields do have biological consequences. Five hundred deaths a year in the United States are attributed to accidental electrocutions. About 100 V/m may cause lethal cardiac fibrillation. Similar currents can restart heart action after cardiac arrest, and smaller electric fields regulate heart action and excite other muscular action. The weakest fields that are definitely known to generate biological effects in humans are the fields of about 0.2 V/m that act on the dark adapted eye to generate visual phenomena (phosphenes). There have been claims for other effects -- such as bone healing -- at fields as small as 0.1 V/m that are plausible, but not incontrovertibly established. Hence, the fields of 10 millionths V/m, from the electrical power distribution system, are about 10,000 times smaller than the smallest fields known to (harmlessly) effect humans.

Direct magnetic effects are also possible. Bees, some fish, and perhaps birds and other animals navigate by use of compasses of magnetite (lodestone) crystals imbedded in their cells. But at 60 reversals a second, the magnetic forces cancel out and the energies transmitted to magnetic elements in animals by 60 Hz, 5 milligauss, fields can be expected to be less than 1/10,000 kT. Neither birds, bees, fishes, nor humans can even detect such weak 60 Hz fields, let alone be harmed by them.

However, there are many laboratory experiments (I have heard that there are up to one hundred) that purport to have demonstrated effects of very weak fields on cells in vitro. All have been accepted without a rational, accepted model for biological interactions of EMF. Are they all wrong? If so, why?

The probable answer is that experimental errors have been accepted as real effects. Error explains the incoherence and lack of replication of the positive reports. It also explains the almost universal lack of a dose-response relation. After more than 20 years of such studies, no well-defined, replicated demonstration of the effects of very weak fields has emerged. Error is the best explanation for all observed reports. (Two workers described in the early 1990s a threefold increase in Myc oncogene expressed RNA on exposure to a low-frequency electromagnetic field, which was then implicated in carcinogenesis. The results could not be replicated by two other groups, which had tightened controls and certain calibrations. The repeat work was reported in the Journal of Radiation Research, October 1995, and reviewed in Science, September 1995. The original erroneous report was widely disseminated in the press and reawakened interest in an EMF/cancer causal relationship.)

But if there is so much smoke, is there not fire? Too much smoke with no sight of flame, suggests to experienced scientists that the smoke is only fog. Seven years ago, I served as chairman of a committee that met in Salt Lake City to report on the National Cold Fusion Institute. At that time, there were 100 papers, from 10 different countries, reporting results that were interpreted as evidence of cold fusion. But cold fusion has been tossed into the dustbin of discredited science; there is no cold fusion.

Flawed Studies

Epidemiological studies that claim to demonstrate effects of weak electromagnetic fields have had great public impact because the techniques and results can be stated in (deceptively) simple ways. In fact, much of the work reporting positive effects is critically marred by errors in technique or analysis and none is even nearly definitive.

As an example of the deficits of a relatively good study, I consider the heralded Swedish measurements of Ahlbom and Feychting that have been cited as showing that the magnetic fields from power distribution systems in Sweden considerably increase the probability of childhood leukemia. Among the many malignancies of adults and children living near power lines that they recorded, they reported significant elevations only of leukemia among children who lived in houses that were calculated to have received, on average, more than 1 mG from main power lines over a long period of time; they found 11 cases where they expected 4.5 from their control group. But they also measured the fields from all sources in the houses -- though for a brief time -- and found only 5 cases where the measured fields were greater than 1 mG. They expected 12.5 from their controls. These are not convincing data. Advocates of the EMF/cancer relationship advertised that "calculated" fields cause leukemia. The equally significant result that "measured" fields prevent leukemia was not advertised. Of course, the minute electromagnetic fields -- either calculated or measured -- neither cause nor prevent cancer.

The Swedish result, accepted as advertised, requires that magnetic fields from the use of electricity are responsible for most childhood leukemia. But the leukemia rate of 4 per 100,000 childhood years is the same everywhere in the West -- in the United States and Europe -- independent of variations in the use of electricity. Moreover, in the U.S., the incidence has not changed significantly for at least 50 years, while electrical power usage has increased more than 20 times during that period.

Indeed, a National Research Council, National Academy of Sciences, review that considered all epidemiological evidence concluded that "Magnetic fields measured in the home...have not been found to be associated with an excess incidence of childhood leukemia or other cancers."

In summary, there are very good reasons to believe that weak electromagnetic fields from our electrical distribution system have no biological effect at all. And there is no good reason to believe otherwise. The fear of weak magnetic fields cost the U.S. an estimated $23 billion by 1993 and continues to cost in unnecessary transmission line relocation, abandonment of structures, and loss in property values, etc. The EMF/cancer non-problem should be scientifically relegated into the abyss that has swallowed cold fusion, N-rays, polywater, Lysenko's anti-genetics, and other aberrations.