Biological effects of electromagnetic radiation

Updated June 4, 2006

Click here to go to our page on microwave heating

Doc Bruce Banner,
Belted by gamma rays,
Turned into the Hulk.
Ain't he unglamo-rays!

New for May 2006! Believe it or not, this is a frequently asked question at this web site. Or maybe it is a "frequency asked question". Time to put the rumors to bed, you scared-i-cats… your cell phone, your microwave oven, and the neighborhood cell towers are not going to hurt you. Or cause another Godzilla attack. Sorry.

Disclaimer: this information is for your reference, and is not meant to stand up in court against attacks from some tricky lawyer!

Here's two relevant government bulletins on the subject:

Questions and Answers about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Waves
(by the FCC)

Assessment of Public Health Concerns Associated with Pave Paws Radar Installations
(by Massachusetts Department of Health)

Some of this info on this page was found in Introduction to Microwaves, by Fred E. Gardiol. Merci! Not bad for a French speaking Swiss!

There are people on jobs that get thousands of times higher exposure levels that the rest of us get. If microwave radiation was as deadly as some fools would have you believe, there would be a steady line of cell tower workers, radar operators, and RF lab technicians all taking an early dirt nap. There is no evidence that this is the case. Speaking of cases, how come television lawyer James R. Sokolove doesn't advertise he'll take on electromagnetic radiation liability cases? Maybe he's smarter than he looks. It would be a losing proposition.

Ionizing versus non-ionizing radiation

Microwave energy is non-ionizing electromagnetic radiation. Ionizing radiation messes up molecules, non-ionizing radiation merely heats them. You heat your body every day when you take a shower with more energy than your cell phone could ever muster. Ionizing radiation starts at ultraviolet frequencies (UV), and includes X-rays and gamma rays, as you go up the scale of deadliness. The effects of gamma rays are what changed Dr. Bruce Banner into The Amazing Hulk; if you are worried about gamma rays buy yourself a Geiger counter.

Here's a figure that we shamelessly stole from one of the government publications. Notice that ionizing radiation is higher in frequency than visible light. Microwave radiation is far below visible light; indeed, there is a huge band of infrared between the two. No one worries much about the infrared food warmer and its effect on cafeteria workers, do they?

Electromagnetic energy is carried by photons. The higher the frequency, the higher the energy in each photon. When a certain energy level is reached, the photon has enough energy to knock off electrons from molecules that it encounters. At this point it is called ionizing radiation. The critical energy level is 10 electron volts (eV). One Joule is 6.2x10E18 electron volts, so a single electron volt is immeasurably small. Here's how to calculate the energy of a photon, depending on its frequency:

E=h

h=Planck's constant = 6.626E-34 Joule-seconds

For the ISM band (2.45 GHz) where your microwave oven operates, energy of each photon is therefore 0.00001 electron volts. The power needed to ionize a molecule is one million times higher than this.

Sunlight is far higher in frequency than microwaves, it doesn't penetrate the body, so it is more dangerous at the same power level. Sunlight provides a power level of 100mW/cm2 during the summer months, mostly infrared, but with some visible and ultraviolet energy. The cause and effect of skin cancer is well known, it's the higher frequency UV light that is going to kill you. This is why sunblock that advertises "blocks UV rays" is a good thing!

Tanning beds do far more damage than microwaves. What is wrong with people, why do you need so badly to change your skin color? Please consider interracial marriage so your kids don't have to participate in this ridiculous and injurious passtime.

Microwave exposure levels

A safety factor of 10 applied to the solar radiation level has been widely adopted for RF radiation, the standard is 10 mW/cm2 maximum. This standard applies to continuous exposure; you can get whacked with higher power for short time with no permanent effects.

Microwave radiation exposure is often expressed in terms of incident power density, in mW/cm2. The following table shows the effects of exposure to certain power levels, without time limit:

Exposure to higher power levels has been shown to cause cataracts. How do we know this? During WWII, there were no guidelines for how much radiation a radar operator could take. Solders and sailors were exposed by radars. At a power level of 1W/cm2, pain is induced, so their medical problems were caused by radiation below that level. Thanks to these guinea pigs, we know where the limit is. If anyone has a good "radar burn" story they want to share, send it in and we'll send you a free gift!!!

Cell phones can muster 2 watts. If the antenna was right next to your head, and half the power went into your skull, maybe a power level of 100 mw/cm2 could be produced, but we doubt it. Certainly this power level will never heat up your eyeballs, unless you hold the antenna over your eye when you talk. If you suffer from cataracts, you didn't get them from Lucky Goldstar. Many modern phones pump up the power in areas of low signal quality, so if you really want to minimize your exposure, then consider 1. going outside when you are calling, 2. talking less, listening more, and 3. moving closer to the cell tower!

No study has proven that RF radiation at less than 10 mw/cm2 could cause cancer. It is possible that a cell phone were near enough to male genitals, temporary sterility could be caused. Unless you are talking on a phone it is not transmitting, so you shouldn't have to worry about proximity effects unless you are a circus contortionist. In any case, there is no shortage of people on the planet, so a little temporary sterility wouldn't be a bad thing.

Microwave ovens are allowed to leak 5 mw/cm2 at a distance of 2 inches away. Power level will drop off as the square of the distance, so 20 inches away it can be no more than 0.05 mw/cm2.

Cell towers will never put out anywhere near 10 mw/cm2 to pedestrians near by. Maximum effective radiated power (ERP) is on the order of 100 watts, but remember, ERP includes antenna gain; the actual power that is radiated is on the order of a few watts. By the time it reaches pedestrians, out at 100 meters for example, the power density is no more than 0.001 mw/cm.

Pacemakers are designed to handle 10 mw/cm2, no problemo.