Editor's note: Bernard Leikind is a physicist. He has researched and taught at the University of Maryland, UCLA, General Atomics and the Livermore Laboratory. He has written essays about the cell phone radiation controversy for the Skeptic, a publication of the Skeptics Society, a scientific and educational organization that examines controversial claims. He pays T-Mobile about $40 a month for his cell phone service, which constitutes all of his financial dealings with cell phone companies. Click here for another viewpoint on cell phones and radiation.
(CNN) -- This week, the World Health Organization's International Agency for Research on Cancer announced that it believed cell phones were a "possible" carcinogen, putting them in the same category as diesel fumes, dry cleaning fluid, talcum powder and coffee. They are making a mistake.
It is too large and complex a matter to work out the details of their errors here. They discount the fundamental results of their own major studies, choosing to emphasize the questionable data from a small sub-group of their subjects. They ignore the century of physics research that strongly establishes the facts.
Microwaves from cell phones cannot cause cancer. This fact arises from more than 100 years of experiments and thought in electromagnetism, quantum mechanics and thermodynamics.
A cell phone radiates about 1 watt of electromagnetic waves. The waves go in all directions to find the cell tower. Molecules in the user's hand, ear, scalp, skull and brain absorb the radiation that passes by. Microwaves try to grab molecules and shake them. The radiation fields love water molecules, and there are many of those in a brain. The fields try to shake what they grab back and forth about a billion times a second.
All those molecules, however, are close to many neighbors. They continually knock into each other, transferring energy. Each molecule also vibrates, rotates and twists. The frequency of the collisions that exchange energy between all the molecules is about a trillion times a second. As the microwaves try to shake molecules a billion times a second, the molecules are sending the incoming energy to their neighbors a thousand times faster.
The energy from the phone's microwave fields rapidly spreads throughout all of the molecules in the tissues. This energy forms a part of the tissue's internal energy, and as the internal energy increases, the temperature increases.
Blood from elsewhere enters the warmed tissue. It absorbs some of the new energy and carries it away throughout the body. Eventually, the energy passes to the environment.
These facts describe the process by which any molecules absorb microwave radiation. If a researcher wishes to propose some mechanism by which cell phone microwaves might cause cancer, he or she must begin here.
But any such proposal faces an insurmountable problem. We all know of many processes that do exactly the same thing as the microwaves. These other processes are more intense -- some of them many times more intense -- than any cell phone's microwaves. If increasing tissues' internal energy with microwaves causes cancer, then so will these other processes.
What are these other processes? Here are some: basal metabolism, fever or inflammation, wearing a ski cap and scarf, drinking a cup of hot coffee or tea or a bowl of soup, and exercise.
A cell phone radiates about a watt of power, similar to a tiny holiday light. The body absorbs a part of that, which is rapidly spread throughout the body by the blood. This is much smaller than the amount of power produced by the chemical reactions that keep our cells alive, expressed in watts per kilogram. Converting the number of food calories I burn in a day to watts (a physicist's power unit), I am like a 90-watt light bulb.
When I exercise on a treadmill, in 30 minutes I burn 500 or 600 calories. Converting that to power gives about 1,200 watts. Divide by 85 kilograms, my mass, to find that while I am exercising, about 14 or 15 watts per kilogram appear throughout my body.
If less than 1 watt per kilogram from the cell phone can cause cancer, by some unknown means, then why doesn't my exercise, which is more than 15 times more intense, also cause cancer? Surely, we would have noticed if it did. I may sprain my ankle jogging along the street, but I will not give myself cancer.
The radiation from a cell phone is more intense in the caller's skin and hand, ear, scalp and skull, than it is in the brain. Skin cells replicate many times more often than any brain cell, which makes them more vulnerable to the breakdowns that lead to cancer. Why aren't we seeing an epidemic of skin cancer?
Readers need not worry about developing brain cancer while using their cell phones. I recommend, however, that you do not text while you are driving, and that you always wear your seat belt.
The opinions expressed in this commentary are solely those of Bernard Leikind.