The Data Proves It: Cell and Wi-Fi Radiation Won’t Harm You

We now know enough over a long-enough period to make a strong conclusion

I recently received an email asking my take on the health effects of Wi-Fi and cellular phone usage. In years past, mostly in the 00’s, I wrote up every new study and examined them closely. I hadn’t as thoroughly reviewed the state of what’s known, so I wrote a long reply that I’m sharing here. I’m sympathetic to people who want to find an answer for modern ailments—their own or other people’s—but electromagnetic radiation is clearly not it.

Oddly, people seem less concerned about the more likely culprit: massive pesticide exposures in food and the environment, prescription drug outflow into water supplies that wind up back in our bodies, and the horrible dangers of microplastic exposure, about which we’re learning more of the impact every day.


It’s very easy to expect that Wi-Fi or cellular EMF could cause problems. People walk by signs in everyday life that warn about microwave/cell tower radiation, because there are now so many cell towers in cities, required by the higher frequency bands now in common use for networks. (These higher frequencies have shorter wavelengths, and travel less far than comparable lower-frequency signals using the same amount of power, so you need more of them to cover the same area as lower frequencies.)

A few blocks from me, a small grocery store has a pretty elaborate installation on their roof—which probably earns them more money than the grocery store profits, honestly. The back side of the store has locked ladders and equipment sheds, and it’s plastered with warnings about getting close to the transmitters a few dozen feet overhead. (The signal power under a transmitter is actually pretty low due to intelligent antenna design.)

And so many times—in the U.S. in particular—a given industry has openly lied about the long- and short-term safety of its products or machinery. I mean, why trust drug companies after Vioxx? Why trust anybody after the history of tobacco and cancer?

The useful data point here, however, is that 15 to 20 years ago, the concerns about cellular and early Wi-Fi were far higher than now, because it was not unreasonable to wonder whether we were all guinea pigs. It was possible to discuss the exceedingly low intensities of exposure, and still think that hundreds of millions of people were “testing” whether new technologies were safe. Enough studies hadn’t been done, and enough people hadn’t used phones or Wi-Fi for long periods of time to figure out patterns.

However, we’re now decades in cellular use, now by billions, and 20 years into Wi-Fi. The results have become ever clearer:

  • Studies don’t reveal significantly elevated risks.
  • Those that find some risk have methodological and design problems that produced other odd results.
  • Cancer rates for those forms that would be expected to increase because of proximity or biological effects haven’t increased over the last two decades.

A fair number of metastudies, which analyze groups of studies to look at statistical flaws and patterns, have examined chunks of research about cellular and general human-created electromagnetic radiation exposure. The metastudies find the same results, or tease out problems with some of the data—a metastudy can help tease out an outlier.

There’s also a problem in some earlier studies that were widely cited as “proving” an increase in cancer: They engaged in “p-hacking,” which refers to the common measurement of probability (p), where researchers need to find a probability of p < 0.05 (less than 5% probability that the results were by chance), which is used to measure significance. No matter how slight the result, it can be cited as “statistically significant” with a score of p < 0.05.

I read many studies in the 2000s (the “oughties”?) in which the research appeared to look for one result, but failing to obtain a desired result, then “found” a bunch of other p < 0.05 results by chopping up the data into other arrangements than those stated at the study’s beginning. This was considered not usual at the time, but was common, and is increasingly considered illegitimate. A celebrity Cornell University professor’s lab engaged in this practice, according to Buzzfeed investigations, and he resigned recently (effective next year) after a number of his group’s seminal papers were retracted or corrected.

More critically, any study that shows statistical significance for an effect from exposure from cellular signals or Wi-Fi networks should be reproducible. None that had any poor results were. One study has been considered dubious because one of the “p-hacking” results from its data found that using a cell phone a lot apparently reduced the cancer rate in an odd demographic group of people, for which there’s no sensible biological explanation, and thus is attributable to design flaws in the study.

More recently, large-scale, long-term rat studies found nothing conclusive. The New York Times has a very good write-up on the problem with the outcomes, which involved massive exposure of rats that don’t really match up with plausible human exposure, and, in one of the studies, found male rats had more tumors, but female rats didn’t! Again, this seems an issue with study design and errors, than with outcomes.

(Update: That link is from February 2018, and the Times coincidentally published a newer examination of the final data just days ago after I wrote this, which has clearer evidence that male and only male rats had a higher risk. However, all the caveats apply, including the critical one that the cancers identified in rats haven’t increased in frequency in the general population, nor in studies that characterize cell phone users by heaviness of use. Otis Brawley, chief medical officer of the American Cancer Society, told USA Today in regards to the new research, “The incidence of brain tumors in human beings has been flat for the last 40 years.”)

The American Cancer Society has written up in a very readable and sensible way the current understanding of risks, and provided short analyses of key studies, as well.

Even if it ultimately turns out that there’s a slightly elevated risk in a cell phone—an elevated risk that might result in a handful more cancers globally than models would predict—there’s the great news about that: All the studies that demonstrate even the slightest possibility are based on holding a cell phone against your head. So, as the American Cancer Society recommends, if you spend a lot of time on a cell phone talking, you can use various ways to keep it further away.

The key factor is that electromagnetic radiation decreases in intensity proportionately to the inverse square of the distance from the source. What does that mean? Moving a tiny distance away from a cell phone, even inches, dramatically reduces the intensity of the signal with which you’re interacting. Move a foot away, and it’s extremely low.

You’ll note I’ve barely mentioned Wi-Fi. That’s because home routers, corporate routers, and Wi-Fi radios in phones and computers already use a fraction of the signal strength of cellular phone, and because you rarely hold a Wi-Fi device up to your head, which is of the greatest concern when it comes to elevated health risks.

Many phone carriers offer Wi-Fi calling, which routes “cellular” calls over a Wi-Fi network if you have the feature available and turned on. If so, then you’re making calls using a signal that may be 10 to 1,000 times less intense than a similar cellular signal—which itself isn’t very intense. Wi-Fi and cellular are both great successes in using very, very low power levels to carry large amounts of data.

While cellular towers and Wi-Fi base station have much stronger signals than a phone or laptop, you don’t hold them up your head, either. Even if your Wi-Fi router is just feet away, the inverse-square rule applies: the signal strength drops off so quickly, that it’s barely distinguishable from noise. Cell towers use far greater power, which is why they’re located up high and away from people, so that the strongest portion of the signal has dropped off before it interacts with human bodies.

When a phone or other device transmits, it uses a higher power level, but it’s much lower than what is found on a tower or router. And modern cell phones and Wi-Fi radio systems use clever systems to focus energy in the right direction. Your head doesn’t transmit radiation very well, so the antenna systems tend to focus power away from human bodies and parts in any case.

Between the physics and the current research, there’s little chance of increased risk for us to have health problems due to cellular and Wi-Fi devices and networks. The physics help clarify why people who don’t talk much on their phones in any case have effectively zero increased risk.

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