U.S. markets open in 2 hours 15 minutes

Is cell phone radiation actually dangerous? We asked some experts

Simon Hill
can cell phones cause brain cancer phone radiation

Editor’s note: This article was originally published in April 2015. We’ve updated it at the bottom with new research and information. You can skip to the update by clicking here.

“It’s looking increasingly likely that cellular phones (mostly smartphones these days) are harmful in terms of cancer risk, particularly to the head and neck. A lot of scientists have come around to the view that radiofrequency radiation is probably carcinogenic because of new research that has emerged since 2011.”

That was Joel M. Moskowitz, director of the Center for Family and Community Health, at the University of California at Berkeley. 2011 was the year the World Health Organization’s International Agency for Research on Cancer classified radiofrequency electromagnetic fields as “possibly carcinogenic to humans.” A panel of 31 expert scientists from 14 different countries concluded radiofrequency radiation, which is emitted by cell phones and other wireless communication devices should be placed in Group 2B alongside a fairly long list of other substances that include lead, coffee, nickel, and gasoline.

But is it really so dangerous? Despite the passionate views espoused by many experts, others are confident the risk is overblown, or at least reluctant to push for sweeping societal changes. Should you be afraid, or gab away as usual? We asked a few experts to find out the truth.

Independent studies are showing the danger

Cell phone emissions were classified as “possibly carcinogenic” based on an increased risk of glioma, which is the most common form of brain cancer, but they were also strongly linked with another type of tumor, benign acoustic neuromas. A lot of the available evidence back in 2011 came from a series of studies known as the Interphone studies, which were partly funded by the wireless communications industry.

“I’ve been tracking the research for five years now and the evidence of the effect is growing stronger,” Moskowitz told Digital Trends. “This is perhaps in part because the new studies are independent, not funded by the wireless industry.”

Back in 2006, Henry Lai, a professor emeritus at the University of Washington analyzed all available studies on cell phone radiation from 1990 to 2006. He found that 50% of the 326 studies showed a biological effect from radio-frequency radiation, but when he divided them into independently funded studies and those funded by the wireless industry he found the split was 70 – 30.

“Even if you accept all the industry studies, you still end up with 50-50,” Lai told Seattle Mag in 2011. “How could 50% all be garbage? People always start with the statement ‘hundreds of studies have been done on this topic, and no effect has been found’ — but this is a very misleading statement.”

Another potentially telling revelation is that the industry can’t get product liability insurance for mobile devices. Some people within the insurance industry feel that there’s a real risk of a wave of lawsuits related to brain tumors and other conditions caused by cell phones over the next couple of decades. Insurance giant the Swiss Re Group included “unforeseen consequences of electromagnetic fields” in its Emerging Risk Insights report.

“Governments are flying blind on this, they’re either ignorant or they’re in denial,” Moskowitz said. “In part it’s ignorance, but in part, they’re getting pressure from an industry that dwarfs big tobacco. It’s just too profitable, about a sixth of your cell phone bill in the U.S. goes to the government in fees or taxes.”

Do we all have our heads in the sand? This is a controversial topic and it’s hard to get definitive answers. We spoke to Dr. Kurt Straif, head of the World Health Organization program that classified radiofrequency electromagnetic fields as “possibly carcinogenic” back in 2011. In Straif’s eyes, the situation is far muddier.

“We don’t know for sure if it’s causing cancer or not. We’ve done almost 1,000 different agent assessments,” Straif told Digital Trends. “This is probably the most heated controversy in terms of strong believers — scientists in the field that say we already know it’s causing cancer to the other extreme that says every additional cent spent on research is wasted because we know it can never cause cancer.”

The IARC Monographs program Straif headed up was formed with the backing of the World Health Organization and the United Nations, at the request of member states looking to identify substances and circumstances that are known to cause cancer in humans, and to make that information available for cancer prevention.

An independent advisory group suggests topics and the Monographs group decides what to pursue. It gathers all the published research, identifies the best experts in the world for each topic, and they draft working papers, and then there is an 8-day meeting to classify each possible carcinogen and create a volume of Monographs.

Dr. Kurt Straif, left, led the World Health Organization program that classified cell phone radiation as “possibly carcinogenic to humans.”

“The Monographs are the most authoritative program in cancer-hazard identification, running for the longest time, looking at all types of environmental exposure, but also known for being the strongest program in terms of a very strict policy to exclude conflicts of interest,” Straif said. “Scientists with a link to industry, or on the other hand, scientists with a very strong link to advocacy groups, would not be eligible to serve on the working group.”

He points out that, though the Interphone study was partly funded by industry, there was a very strict firewall in place overseen by the Union for International Cancer Control.

“I did not sense any strong orchestrated efforts by industry to influence the outcome of the 2011 meeting,” he said.

The IARC is no stranger to controversy and it does not bend to big business. Take for example the recent classification of glyphosate — the main chemical in the pesticide Roundup — as “probably carcinogenic,” a move that incurred the wrath of Monsanto, the pesticide’s maker. Glyphosate is in group 2A, which is still one step down from Group 1, “carcinogenic to humans.” Radiofrequency EMF radiation was placed in Group 2B, largely based on cell phone studies. So what does the “possibly carcinogenic” classification actually mean?


“It means that there is scientific evidence, in this case limited evidence from the human studies, that it could cause cancer in humans,” Straif said. “There is also limited evidence from animal studies, and there is weak mechanistic data. These three things together result in the evaluation of possibly carcinogenic.”

There is no firm plan to reassess radiofrequency EMF radiation, but Dr. Straif said it is on the radar, and if important new evidence was to emerge, the IARC Monographs group could make it a priority.

“Knowing about the studies that have been published since 2011, I think that the epidemiological evidence is still limited,” Straif said, making it clear that this is his personal opinion and not that of the IARC group. “It has not changed in one or the other direction. There are lots of different scientific groups out there. Some think with the new publications that the human evidence is now sufficient to result in a Group 1 classification as a known human carcinogen. I don’t think these studies would change the current overall evaluation of 2B.”

How much could smartphones increase your risk of brain cancer?

“It has been understood since 1975 that very low-intensity exposure to microwave radiation can open the blood/brain barrier,” Moskowitz said. “It evolved to keep larger molecules out of the brain tissue. Most people nowadays have around 100 toxins in their blood system at any point in time. Some of those toxins may be able to penetrate brain tissue in the presence of low-intensity exposure like Wi-Fi, cell phones, cell towers, wireless baby monitors, and wireless smart meters.”

Still, it’s difficult to put the risks into context.

It’s worth mentioning that radiofrequency electromagnetic fields aren’t just the product of cell phones. Straif explained that Wi-Fi and Bluetooth are in the same category, but most of the evidence they were able to draw on for the IARC classification of “possibly carcinogenic” came from cell phone studies.

“If you think in terms of levels of exposure from Wi-Fi or Bluetooth, these are orders of magnitude lower,” Straif said. “Even if there is a risk, it would be much lower.”

Swedish oncologist Dr. Lennart Hardell is convinced of the carcinogenic effect and is one of the few researchers to have conducted long-term independent studies. He suggests that the risk of developing brain cancer is three times higher after 25 years of cell phone use. But what does that actually mean?

According to the National Cancer Institute, 5 out of 100,000 Americans under the age of 65 were diagnosed with brain cancer between 2006 and 2010, which puts your chances at about 0.005%. If this rate tripled, it would make it 15 out of every 100,000, bumping your chance up to 0.015%.

“The risk of brain cancer after 10 years is roughly doubled,” Moskowitz said. “Studies have shown that the risk of tumor development is on the side of the head where the phone is predominantly used.”

The American Brain Tumor Association put us in touch with Dr. Barnholtz-Sloan at Case Western Reserve University School of Medicine. She downplayed a causal link between brain cancer and cell phones.

“I would love it if we found a risk factor for brain tumors like smoking for lung cancer, so we could advise patients and their families,” Dr. Barnholtz-Sloan said. “But we haven’t found one yet.”

The IARC puts incidences of lung cancer at around 40 out of 100,000 for Northern America. The latest data from the Central Brain Tumor Registry of the United States puts the incidence rate for newly diagnosed malignant brain tumors in the U.S. at 7.25 per 100,000. The official definition of a rare cancer in the U.S. is anything that affects fewer than 15 out of 100,000 people each year.

“The current evidence about the association between using cell phones and brain tumor risk is inconclusive,” Barnholtz-Sloan said. “Some studies have shown positive associations and some have shown negative results. The studies with positive associations show a risk of 1.5 to 2.0, which is small in comparison to the relationship between smoking and lung cancer, hence multiple other factors must be involved to explain the risk of a brain tumor. With the uptake of cell phones over the last 20 years, if cell phones were truly a major risk factor for brain tumors we would have expected an increase in brain tumor diagnoses, but the diagnosis rates are relatively stable.”

Dr. Barnholtz-Sloan

It’s hard to know how worried we should be about these risks. We aren’t seeing the kind of obvious correlation there is between smoking and lung cancer, for example, where the Centers for Disease Control and Prevention estimates smokers are 15 to 30 times more likely to get lung cancer than non-smokers. But we also don’t have as much research to draw on for cell phone exposure, and we know that usage is climbing dramatically. Many of us plan to use cell phones for the next 50 years or longer. It would be nice to know they’re safe.

“I think the results are inconclusive,” Dr. Barnholtz-Sloan said. “Which, in my view, mean’s that the jury’s still out.”

The official position

Despite years of research, it seems we still don’t really know for sure whether cell phones cause cancer. Many official agencies make it clear that no link has been proven, but they go out of their way not to rule it out.

  • FCC: The FCC said “there is no scientific evidence that proves that wireless phone usage can lead to cancer or a variety of other problems, including headaches, dizziness, or memory loss. However, organizations in the United States and overseas are sponsoring research and investigating claims of possible health effects related to the use of wireless telephones.”
  • CDC: The CDC claims “there is no scientific evidence that provides a definite answer to that question [Can using a cell phone cause cancer?]. Some organizations recommend caution in cell phone use. More research is needed before we know if using cell phones causes health effects.”
  • National Cancer Institute: The National Cancer Institute says that “studies thus far have not shown a consistent link between cell phone use and cancers of the brain, nerves, or other tissues of the head or neck. More research is needed because cell phone technology and how people use cell phones have been changing rapidly.”

More health dangers from phones

With tobacco, the only clear evidence early on linked it to lung cancer, but every time it was reassessed, additional cancer sites were added. This won’t necessarily be the case for cell phones, but it’s possible.

Brain cancer is not the only risk that has been associated with prolonged cell phone use. There have been studies linking it with tumors in salivary glands and thyroid glands. There’s increasing evidence of a link with neurological disorders and neurodegenerative effects, and it may negatively affect fertility. Some scientists have even suggested that the increase in cases of ADHD and autism could be related to the rise in cell phone use.

A growing number of people are also self-diagnosing electromagnetic hypersensitivity, which is associated with a long list of symptoms and supposedly triggered by proximity to cell phones and other electromagnetic fields. It’s not a recognized medical condition, and there have been double-blind studies with positive and negative results.

Whether it’s a real condition or not, sufferers certainly believe it is real. Popular Science ran an interesting piece on the town of Green Bank, West Virginia where there’s a growing electrosensitive community who’ve moved there because the town is in the heart of the National Radio Quiet Zone.

But technology is getting safer, right?

“We know that with the new technology, the third and fourth generation, the exposure, in terms of non-ionizing radiation, has reduced by an order of magnitude,” Straif told Digital Trends. “The overall trend for exposure per minute has reduced since [the original studies, such as the Interphone study, which ended in 2006]. However, at the same time, probably the talk time on the phone for the average person has increased.”

Moskowitz disagrees.

“We have no indication that 3G or 4G is any safer and, in fact, the preliminary research on both suggests that it may be more harmful,” he said.

Part of the issue is that the standards that are currently in place to govern radiofrequency emissions were never designed with cell phones in mind.

“The current federal standards and international guidelines are way too high because they were only developed to protect against thermal effects, yet most of the studies are showing non-thermal effects,” Moskowitz said. “They clearly should be revisited. Many experts have called for such a review and that effort continues.”

You can check the SAR (Specific Absorption Rate) rating for your phone. Manufacturers have to publish this information publicly. Here is Apple’s RF exposure data for the iPhone 6 as an example. It tells you about the amount of radiation being absorbed into your body when you use the device.

Some countries are taking the threat more seriously than others. Belgium passed legislation that forces the manufacturer and retailer to prominently display the SAR value of each device. The country has also banned the sale or advertising of cell phones for children aged 7 and under. France recently passed similar laws including a ban on Wi-Fi in nursery schools and introducing restrictions in schools for children up to the age of 11.

What can you do if you’re worried?

“If you are concerned, and you want to take some steps to reduce your exposure, there are easy ways to do that,” Straif said. “For example, using a hands-free kit, which drastically lowers the exposure to the brain, or talking less over the phone.”

There are a few obvious precautions you can take if you want to reduce your exposure and risk, but they mostly amount to not using your phone.

  • Limit the amount of time you use your phone
  • Don’t keep your phone next to the bed at night
  • Turn Airplane mode on or turn your phone off when you don’t need it
  • Don’t carry your phone close to your body
  • Don’t hold it to your head, use a headset for calls instead

“Reducing our exposure considerably is feasible and would probably do a lot to reduce the public health burden,” Moskowitz said. He has a one-page tip sheet offering more advice.

Future research and answers

“What we really need is better epidemiological studies,” Straif said. “Ideally cohort studies that go from the exposure to the cancer, instead of case-control studies where we select people with cancer and controls and try to assess their exposure retroactively. Such cohort studies could, for example, make use of the objective data from service providers about the usage of mobile phones, so we would get a much better picture of the actual usage. These studies are in the pipeline, but they take a long time.”

For some people that evidence can’t come fast enough.

“People love these devices,” Moskowitz said. “They’re great devices for a variety of reasons; People don’t want to believe that they could possibly cause them harm. The public health establishment in the U.S. is also in denial, but it’s just a matter of time before this issue comes back to bite us.”

Four years on – September 2019 update

A lot has changed in the last four years, but the argument over the potential for cell phone radiation to cause harm to humans continues. The National Toxicology Program released its final reports in November 2018, from a series of studies that cost $30 million and took more than 10 years to complete. It concluded that “there is clear evidence that male rats exposed to high levels of radiofrequency radiation (RFR) like that used in 2G and 3G cell phones developed cancerous heart tumors.”

There was also some evidence of DNA damage and glioma. Unfortunately, precisely what that means for humans is not clear.

“These studies demonstrate that RFR (radio-frequency radiation) is a potential hazard,” National Toxicology Program (NTP) researcher Michael Wyde, Ph.D. told Digital Trends. “Further characterization is required to determine whether the effects observed in our studies are relevant for humans.”

The Food and Drug Administration was quick to release a statement downplaying the report and pointing out that, “Animal studies like this one contribute to our discussions on this topic, but we must remember the study was not designed to test the safety of cell phone use in humans, so we cannot draw conclusions about the risks of cell phone use from it.”

This sounds reasonable, but it is worth pointing out that the U.S. guidelines for radio-frequency exposure that the FDA upholds were established by the Institute of Electrical and Electronics Engineers (IEEE) and based on research conducted in the 1980s on rats. The SAR (specific absorption rate) standards that are in place, which haven’t changed since 1996, were set based on when animal behavior changed — rats were trained to press a bar for food when they heard a certain sound and then irradiated for 30 to 60 minutes until their body temperature increased and they stopped pressing the button. If we can’t draw conclusions about the NTP study, why is this earlier animal research still the basis of our safety limits?

“Regulatory agencies are responsible for establishing and maintaining appropriate exposure limits considered to be safe for humans,” Wyde said in an email. “It is the responsibility of these regulatory agencies to periodically review and update these limits as new data emerges in an effort to maintain safe exposure levels for consumers.”

Again you may reasonably wonder why, if cell phone radiation is causing cancer in humans, we haven’t seen major trends to that effect.

“While oftentimes a response can be identified by looking at trends over time with respect to background rates of cancer, it is difficult to establish an association in this manner due to the number of confounding factors that affect cancer development,” Wyde said. “Additionally, it may take years for a clear pattern of association to emerge because there can be long latency periods that exist between exposure to an agent and the ultimate development of cancer. It may take 20-30 years to identify these trends if they occur.”

The National Toxicology Program is continuing with an ongoing program of study to investigate the potential health effects of radiofrequency radiation and so are many other institutes around the world.

The issue of SAR levels is also pertinent in light of the recent revelation from the Chicago Tribune that devices from some phone manufacturers, including Apple and Samsung, exceeded the legal safety limits in their tests, in one case putting out more than double the level of radiation reported to federal regulators, though this has been disputed by the manufacturers. The report has already sparked the filing of a class-action suit against Apple and Samsung. It’s not the first time that assertions like this have been made — you can find an exhaustive record at French website Phonegate Alert.

Reaching out to Dr. Joel Moskowitz again, he remains firmly convinced that cell phone radiation is causing damage. He said a lot of higher-quality studies have emerged in the last few years and he has been highlighting abstracts of newly-published scientific papers on wireless radiation and electromagnetic fields (EMF) since August 2016.

“Something is going awry within the decision-making bodies in our government,” he said. “Nobody in power really wants to know the cost of unleashing this technology upon the public and upon the environment as well.”

As the fifth-generation (5G) of mobile networks begins to roll out, a lot of people have raised concerns about whether 5G might be dangerous. The higher frequencies signals that some companies are employing for millimeter waves, for example, don’t penetrate the human body in the same way that lower frequency signals do.

“At these high frequencies, RF radiation is fully absorbed in the skin and does not reach underlying tissue,” Wyde said. “Consequently, little or none of this RFR would reach organs that developed tumors in our studies of RFR in male rats.”

Unfortunately, that doesn’t necessarily mean 5G will be safe. A lot of different frequencies and technologies will be employed, not just millimeter waves, and even in the case of millimeter waves, there isn’t any conclusive research about the impact on humans.

If you want to dive down the rabbit hole of research, the National Cancer Institute’s fact sheet is a great place to start, the FDA has a list of current research, or you can get even deeper with something like the EMF Portal which has been summarizing data on the effects of electromagnetic fields. While a lot more research has emerged over the last four years, a definite answer to this question still eludes us.