Monday, April 26, 2010

Do Radio Waves Cause Cancer?

This was a question a student asked last week during the electromagnetics class that I'm teaching for the first time this semester. Not wanting to turn the rest of the class period into an engineering ethics seminar, I said some brief words to this effect: "There have been many studies of that question, and although you will find people who disagree, the general conclusion is that there is no repeatable connection between radio waves and cancer." But I wish I had known about the article that journalist George Johnson published online in Slate last week. Not only did he look into the question, he tried to give himself an electromagnetic headache by camping in a nest of microwave towers in New Mexico one night. As it turned out, it didn't work.

Johnson was inspired to try this by a Los Alamos scientist who describes himself as "electrosensitive." The scientists claims that exposure to too much radio-frequency radiation gives him a variety of symptoms such as headaches and insomnia, though cancer was not on his list of complaints. So Johnson made the trek up Sandia Crest to the "Steel Forest" where dozens of radio, TV, and microwave transmitters broadcast to a large area of New Mexico. In the event, he slept well and suffered no headaches or other adverse symptoms.

Johnson explains that some of the complaints of so-called electrosensitives may be explained by a phenomenon known to historians as a hysterical epidemic. It turns out that some people with genuine but ill-defined physical complaints are prone to latch on to a current cultural phenomenon and become convinced that it is the source of their problems. This is not to say that the maladies are not subjectively real—if someone tells you they have a headache, there is no way to prove they are wrong. But the cause is another question altogether.

And most people are familiar with the psychiatric problems that lead some people to believe things that are clearly at odds with reality. For example, years ago when I taught microwave engineering in Massachusetts, one of my colleagues received a phone call from a woman who was convinced that the government had implanted a secret radio chip in her body. She wanted to know if we had any equipment that we could use to examine her in order to find the thing. Nobody volunteered, needless to say. Before the advent of miniature electronics, when radios were novel pieces of furniture in 1920s living rooms, some psychiatric sufferers would complain to their doctors that spies were "working wireless" on them. And I suspect that if you go back far enough in history, you might find a case of a person who thought people were telegraphing messages inside his head.

While it is almost impossible in some individual cases to establish the cause of a given subjective complaint, it is quite possible to do systematic large-scale studies of epidemiology and biological effects of electromagnetic radiation. Unlike shorter-wavelength radiation ranging from ultraviolet rays through X-rays, radio waves and microwaves cannot knock electrons loose from atoms in your body, under normal conditions. If the waves are not strong enough to cause localized heating (and no piece of equipment properly used and meeting FCC regulations produces such strong waves), then there is no obvious mechanism by which radio or microwave radiation could cause cancer, headaches, insomnia, or any of the other range of ailments that people sometimes suspect them of causing. Literally hundreds of research studies have been done over the years on this subject, and as Johnson reports, the World Health Organization recently concluded from a review of the world's scientific literature that there is no reason to be concerned about biohazards from the type of low-level radio or microwave radiation that people receive just by living in the modern world among cell phones, computer wireless links, and digital TV broadcasts.

But as engineering ethics has taught me, to know a technical fact is one thing, and to deal with lots of ordinary people who have concerns or even beliefs to the contrary is a completely different thing. The attitude shown by knowledgeable engineers toward lay persons with genuine concerns is crucial. An arrogant, blowoff type of response to a legitimate question can arouse suspicions—which may be entirely unfounded—that the engineer in question is trying to hide something. Every microwave engineer who deals with the general public should be sensitive to anxiety, concern, and even hostility from people who think cell phones or computers or digital TV broadcasts have caused them harm. This is especially true when dealing with situations such as cancer clusters, a statistical phenomenon which can lead to explosive reactions, protests, and lawsuits.

Suppose for example that a cell-phone tower is built in a new neighborhood. There is a non-zero chance that among the population of young children in that neighborhood, a higher than average number of them will come down with some horrible fatal disease such as brain cancer. If a few parents of such victims meet each other, it can happen that they start to suspect something geographic is to blame for their rare and tragic experiences. The need to find an answer to the agonized question, "Why my daughter?" or "Why my son?" in the face of death is a universal one. And sometimes people seize on things they don't understand as a kind of scapegoat or target for action.

These people can have the best of intentions, such as wanting to prevent future tragedies like the ones they have endured. But if they get an unfeeling response from a know-it-all engineer who keeps saying, "You just don't understand, you don't have the technical background that I have," and so on, they are not likely to be persuaded by anything he says, no matter how technically correct it is. Engineers need hearts as well as heads, and this aspect of engineering training is usually neglected.

So perhaps I will let my students know about the Slate article this week, and if they ever happen to run into similar questions, I hope their response is technically correct, of course. But even more, I hope they take the questioner's feelings and situation into consideration as well.

Sources: George Johnson's article "On Top of Microwave Mountain" appeared in the Apr. 21, 2010 online edition of Slate Magazine at


  1. I'm in favor of sensitive engineers.

  2. so does it cause caner i dnt understand this!!!!!!!!!!! im need to know

  3. Lynn, according to WHO there's a possibility cell phones cause cancer. Studies which shown no link between cell phone radiation and brain cancer and others, where investigated in depth and shown the results reported were faked, but again, not even the biggest studies have proven it either...