Who's Afraid of the Big, Bad Power Line?

             or

Will my appliances give me

• Cancer? No.
• Impotence? No!
• Hives? No, no, a thousand times no !!!

Technical details, in *.ZIPped *.PDF and *.HTML format.

The End

So why do some people fear power lines?

Three New Yorker articles by Paul (“The Zapping of America” and “Currents of Death”) Brodeur—followed by three Daily Progress articles—

panicked the general public, not least the governments of Sweden and San Francisco. Why the “Chicken Little” reaction?

Brodeur called it radiation, and anything with the word radiation is

• This is not the first time people have worried about a technological bogeyman that wasn't there: in 1977 Brodeur convinced many to junk their microwave ovens (“The Zapping of America”).

How does electric power work?

• Electricity is generated at a generating station (power plant).
  
  The generating plant produces 60 Hz alternating current.
  Transformers located at the power plant, at district substations, and on local power poles are used to step up and step down the voltage, for reasons having to do with the economics of power distribution.

• Electric power poses hazards of
  and direct electrocution.

  The electrocution hazard goes up with the voltage, so long-distance transmission lines (“power lines”) are especially dangerous.

  We put up with these well- understood risks because of the obvious benefits and convenience of electric power. We also put up with them because we know how to protect ourselves: “Don't touch high voltage power lines!”

• Electric currents in the wires—long-distance transmission lines, local distribution lines, household wiring—as well as the transformers found at various points in the system, create oscillating magnetic fields.

  Some people have claimed that these magnetic fields are a form of ELF (Extremely Low Frequency) electromagnetic radiation that is dangerous to health.

What is electromagnetic radiation?

(and how does it affect you?)

• X-rays, ultraviolet light, visible light,
  infra-red, RADAR (microwaves), UHF, FM radio, TV, AM radio, LORAN and so on are forms of electromagnetic radiation.
  
  They are identical in essence, differing only in wavelength.
  • X-rays and UV rays cause direct biological damage, including damage to cellular DNA (which can in turn lead to cancer).
  • Visible light, IR and radio waves can—if sufficiently intense—all produce heating, burning, and destruction of tissue. Intense microwaves can cause cataracts in the eyes. These forms of radiation do not cause chemical changes in cells and thus cannot possibly induce cancer.
  • When we get down to Extremely Low Frequency electromagnetic effects, ranging in frequency from 10,000 Hz down to DC—for example the pervasive 60 Hz magnetic fields of the electric power system and household appliances—we find no evidence of any biological effect at all.

Why do people think ELF affects health?

• A study in the 1970's claimed to correlate childhood leukemia with proximity to electric power transformers. Since this and other original studies neither measured the actual magnetic field exposure of the leukemia victims, nor did they match for exposure with people who did not get leukemia, they were at best inconclusive. Follow-up work has not confirmed the early reports. The later work did measure magnetic fields, for example field intensity along city streets, as above.
  (It is worth mentioning that the maximum intensity found in these measurements is about one tenth of the Earth's own magnetic field, that all living creatures have experienced since the begining of time.)

  What the follow-up studies found was nothing, as the data below show clearly.

  

  
  

• More convincing is the fact that the rapid expansion of the
  United States' power grid has subjected a very large population to ever-increasing exposure:

  In other words, we have all been guinea pigs in an experiment during the last 90 years. It would be reasonable to expect, if power lines cause disease—cancer in particular—that the incidence of the disease would increase with the exposure. That is, if power lines are unhealthy, why aren't we getting sick?

• But of course it is possible to perform more direct experiments by exposing laboratory animals and cultures of living cells to intense fields of the sort we have been talking about. Nobody has found any effect whatsoever.

  (Well, almost nobody—in 1992 Richard P. Liburdy, a scientist at U of CA, Berkeley, announced he had linked electromagnetic fields from power lines with observable changes in the cells of living tissues.)

  But according to the Associated Press (July 24, 1999) the Federal Office of Research Integrity found that Liburdy had committed scientific misconduct—i.e. fraud—by tossing out data that did not support his conclusions; and that he knew his data manipulations were significant to the claims of his paper.

• My conclusion: sleep tight under your electric blanket!

Perhaps I should finish by remarking that scientists dealing with unsub- stantiated claims and anecdotal evidence labor under a major difficulty. We can't prove a negative proposition—“power lines don't cause hives”—any more than you can prove you didn't commit last week's murder.

That is why the police have to try to prove the definite proposition that you committed the murder. And it is why scientists have to start with a definite idea—“power lines do cause hives”—use it to make a definite prediction, and see whether that prediction is verified.

But if the prediction disagrees with our experience, that does not mean we have proved the proposition was false. It just means that the proposition is less likely to be true than it was before we ran the experiment.

Scientists' inability to prove the negative drives laymen and politicians crazy. But it is also what makes a (good) scientist worth listening to.

The End. (This time I mean it.)