The cellular phone industry was born in the early 1980s, when communications technology that had been developed for the Department of Defense was put into commerce by companies focusing on profits. This group, with big ideas but limited resources, pressured government regulatory agencies—particularly the Food and Drug Administration (FDA)—to allow cell phones to be sold without pre-market testing. The rationale, known as the “low power exclusion,” distinguished cell phones from dangerous microwave ovens based on the amount of power used to push the microwaves. At that time, the only health effect seen from microwaves involved high power strong enough to heat human tissue. The pressure worked, and cell phones were exempted from any type of regulatory oversight, an exemption that continues today. An eager public grabbed up the cell phones, but according to Dr. George Carlo, “Those phones were slowly prompting a host of health problems.”
In December, 2006, an epidemiological study on cell phone dangers published in the Journal of the National Cancer Institute sent the media into a frenzy.10 Newspaper headlines blared: “Danish Study Shows Cell Phone Use is Safe,” while TV newscasters proclaimed, “Go ahead and talk all you want—it’s safe!” The news seemed to be a holiday gift for cell phone users. But unfortunately, it’s a flawed study, funded by the cell phone industry and designed to bring a positive result. The industry’s public relations machine is working in overdrive to assure that the study get top-billing in the media worldwide.
An analysis of an "eagerly anticipated" study using rats and mice by the National Toxicology Program indicates that due such issues as the inconsistent appearances of "signals for harm" within and across species and the increased chances of false positives due to the multiplicity of tests, the positive results seen are more likely due to random chance. The full results of the study were released in February 2018.[10]
In March, however, a peer-review panel of 11 experts from industry and academia voted to advise the agency that it should raise the confidence level from “equivocal evidence” to “some evidence” of a link between cellphone radiation and brain tumors in male rats. (The female rats did not show evidence of a link between the radiation and such tumors.) Two panel members, Lydia Andrews-Jones of Allergan and Susan Felter of Procter & Gamble, proposed the risk upgrade.
In addition, the findings might be influenced by the fact that the study subjects owned cell phones that were in some cases manufactured two decades ago. The way we use cell phones and the networks they’re operated on have also changed since then. Last, cancer can develop slowly over decades, yet the studies have analyzed data over only about a five- to 20-year span.
Some people might consider choosing a phone with a low SAR value. Different models of phones can give off different levels of RF waves. But as noted above, according to the FCC the SAR value is not always a good indicator of a person’s exposure to RF waves during normal cell phone use. One way to get information on the SAR level for a specific phone model is to visit the phone maker’s website. The FCC has links to some of these sites here: If you know the FCC identification (ID) number for a phone model (which can often be found somewhere on the phone or in the user manual), you can also go to the following web address: On this page, you will see instructions for entering the FCC ID number.
Instead, we have to rely on “observational” data, tracking people’s real-world cellphone use and their disease incidence. Studies using observational data tend to be weaker, messier, and less clear-cut than experimental studies like RCTs. They can only tell us about associations between phenomena, not whether one thing caused another to happen. So that opens up a lot of the ambiguity we’re going to delve into next.
I don't know why, but I recently had a concern about the fact I keep my smartphone in my pocket for a good part of the day. Was this a "smart" idea, or was there a potential problem with phone radiation? To address this concern, I searched for answers on the Internet. There were a lot of contraptions, many of which seemed to be too good to be true. The one that looked the most promising was Blocsock, not cheap at $24 for the high-end model with the pouch, but it did say it blocked 96% of the cell phone radiation from your body by having special radiation-blocking material on one side, with the side facing away from your body regular material so the phone could still communicate with the outside world. Cheap eBay knockoffs had material on both sides, meaning when you put your phone in them, your phone could't communicate with the outside world! Others did not have the testing results that assured how well the blocking material worked. There is a very detailed SAR test report validating the Blocsock, which I found at You can Google it. It is a very exhaustive testing report!
A recent large study by the US National Toxicology Program (NTP) exposed large groups of lab rats and mice to RF energy over their entire bodies for about 9 hours a day, starting before birth and continuing for up to 2 years (which is the equivalent of about 70 years for humans, according to NTP scientists). The study found an increased risk of tumors called malignant schwannomas of the heart in male rats exposed to RF radiation, as well as possible increased risks of certain types of tumors in the brain and adrenal glands. But some aspects of this study make it hard to know just how well these results might be applied to cell phone use in people. For example, there was no clear increased risk among female rats or among male or female mice in the study. The doses of RF radiation in the study were also generally higher than those used in cell phones (ranging from 1.5 W/kg to 6 W/kg in rats, and 2.5 W/kg to 10 W/kg in mice), the animals’ entire bodies were exposed, and the amount of time they were exposed was longer than most people typically spend on the phone each day. The male rats in the study exposed to RF waves also lived longer, on average, than the rats who were not exposed, for unclear reasons. Because of this, the NTP has noted that the study results cannot be directly applied to humans. Still, the results add to the evidence that cell phone signals might potentially impact human health.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.