Every decade or so, like clockwork, a new technology comes along that changes the way we use our phones. And now, imminently, that technology is 5G.
Carrier companies are racing to get out devices that will work on 5G, which will solve the buffering and lagging data transmission woes of 4G LTE. While those current networks use frequencies of about 400 MHz to 3GHz (pdf), 5G will allow cell service to operate on slightly shorter waves, with frequencies ranging from 3 GHz to 6 GHz. It will also incorporate even shorter waves, called millimeter waves, with frequencies of 24GHz to 52 GHz. Endlessly spinning loading wheels will be a thing of the past.
But not everyone is thrilled about the deployment of 5G, or even existing cell phone technology. A small yet vocal cadre of scientists believe that the radio waves used for cellular communication are not just understudied, but potentially a threat to human health.
As of August of this year, some 250 scientists across 42 countries have signed a petition directed toward the United Nations Environment Programme. These scientists are demanding that the program assess the potential biological impacts of 4G and 5G technology. Their concerns sound alarming. Many of them point to research tying cell phone use to cancer or reproductive challenges.
There’s just one problem: The vast majority of scientists don’t believe these results. The divide between camps is so significant that it’s beginning to look like less of a scientific debate, and more of a standoff between political factions. Science is an exploratory discipline where uncertainty and caveats are the norm. Yet in the case of the 5G debate, both sides are sure that their stance is undeniably correct. That dichotomy isn’t productive for a public that just wants to know how to stay safe.
The reality is, we’ve been here before.
“If you put these claims in context, [they] aren’t new,” says David Robert Grimes, a cancer researcher and physicist at the University of Oxford. Concerns over electromagnetic waves of any type have always loomed over wireless technology, from radio to wifi to 5G: It simply sounds scary to be exposed to a new form of radiation. What has changed recently, Grimes says, is that the risk most recently ascribed to wifi networks is now ascribed to cell phone usage.
There’s a strong logical argument for dismissing those concerns, though. For health purposes, there are two broad categories of electromagnetic waves: those that carry enough energy to knock electrons off atoms, called ionizing waves, and those that cannot, called non-ionizing waves.
We try to avoid ionizing waves, which all have shorter wavelengths than we can see with our eyes. Their higher frequencies give them higher energies, which is what enables them to pluck off electrons in the first place. Ionizing waves include things like UVB rays from the sun, which are about 280 to 315 nanometers in length: They’re why we get sunburns, and in some cases, skin cancer, when the ionizing capabilities of the UVB rays mess with our genetic material. X-rays fall into that category, too; sometimes, the benefits of visualizing your insides exceed the risk of short-term radiation. Still, patients receiving them need to wear some sort of protective lead covering.
5G may seem inherently threatening because it involves the use of shorter wavelengths than previous generations of cell phone transmission technology. But they still fall firmly in the non-ionizing range. 5G radio waves will have orders of magnitude less energy than visible light—which we know is safe. The shortest waves used for communication (meaning those with the highest energy) are still less energetic than any light wavelengths we can see, says Grimes.
Compared to ionizing waves, the wavelengths 5G will use are still relatively long and range from about 10 centimeters to about 0.6 centimeters. (Our skin actually blocks out (pdf, p. 5) these wavelengths better than longer ones used in 4G networks, although neither are ionizing.)
So from a biomechanical standpoint, the waves emitted by cell towers—old or new—shouldn’t be able to damage DNA, and therefore shouldn’t be able to cause cancer.
There’s not a lot of epidemiological evidence that they do, either. Some of the largest studies in this area, funded by the World Health Organization (WHO), have found no correlation between cases of various types of brain cancers and up to a decade of cell phone use based on interviews with thousands of participants in 13 countries. While the WHO’s International Agency for Research on Cancer classifies radiofrequency electromagnetic fields as a “possible carcinogen” (pdf), that classification speaks to a wide range of potential risks—including no risk. Many experiments support the safety of high-frequency waves, a former medical physicist at Temple University told the New York Times.
Case closed, right? For many scientists, the strength of this evidence alone is enough to allay fears about cell phone frequencies, including those used for 5G. Translated to the public, that message has been read as a definitive defense of 5G’s safety. Which is how we got into this pickle.
For the scientific community calling for caution, the current evidence falls short of proving the safety of cell phone frequencies. Because radio waves have been understandably believed to be safe for years, there is considerably less research of their effects than there is of newer technologies—no need to pour more money into a settled issue, the thinking goes.
The one set of safety regulations the US has in place for consumer cell phones comes from the US Federal Communications Commission (FCC), which limits the amount of energy cell phones can emit. The FCC says it’s safe for humans to absorb up to 1.6 watts of energy per kilogram of body weight, measured at a specific tissue site, like the head. This limit is called the specific absorption rate, or SAR.
These limits are based on body temperature: The FCC wanted to make sure that cell phone energy couldn’t give people a fever, basically. But by studying the heating effects to the exclusion of other risks, skeptics argue, scientists were ignoring the potential risk of DNA damage—even though it shouldn’t be possible based on what we know about the electromagnetic spectrum.
This is why in the late 1990s, the US Food and Drug Administration (FDA) commissioned a study from the National Toxicology Program (NTP) to assess if there could be any other biological effects of cell phone radio energy. Toxicologist Ronald Melnick and his team spent several years designing one of the largest animal studies to date, testing 1,260 rats and 1,260 mice. They ensured that the radio waves rodents experienced would be uniform (and not, for example, amplified by their tails, which can act as antennas, he told Quartz).
Each animal received a designated amount of radiation—rats got SARs of 0, 1.5, 3, or 6 W/kg—for nine hours a day, every day, for two years.
Last year, Melnick’s group finally published its results, showing “clear evidence” that prolonged exposure to 2G and 3G waves at 1.5, 3, and 6 W/kg led to increased rates of heart cancer in male rats (the highest number of cases in the highest SAR groups), as well as “some evidence” it caused other types of brain cancer and adrenal gland cancer. In mice, the evidence that some cancers were related to cell phone radio waves was less certain.
In a field with very little competition, the NTP study fueled skeptics’ fire. If a federally-commissioned study found evidence of cancer in rodents exposed to lower frequency 2G and 3G radio waves, what could that mean for the networks we’re using today?
“[The FCC] should not be releasing more spectrum or promoting new kinds of cell phone technology until we understand the effects better and can set guidelines that actually ensure safety,” says Joel Moskowitz, a psychologist who leads the Center for Family and Community Health at the University of California, Berkeley.
Of course, research in rodents is a far cry from long-term trials of human populations. And the NTP study received a lot of criticism from the scientific community for flaws in its design. There weren’t that many rats involved (only about 90 per group were exposed to different levels of cell phone radiation), and the rats that got the most exposure also had the highest survival rates through the end of the study. (Age happens to be a major risk factor in developing cancer.)
But these areas are undoubtedly under-explored. By the very nature of science, it’s really hard to prove that anything is perfectly safe. Nothing in life is, Grimes says. The trick is to catch when something is reliably causing harm—and prove it.
Proof is a slippery concept in public health. In order to definitively show that a particular exposure—in this case, cell phone radio waves—causes a particular health outcome, scientists need many types of studies: Some deliberately exposing people or animals to the waves and tracking if the exposed groups develop certain health outcomes, and some using animal or cell models that can be dissected to determine if the exposure specifically caused the health outcome. A third kind of study, an observational one, can look at the co-occurrence of cell phone use and health effects, as the WHO’s studies have—but that kind of research is less powerful, because it looks to the past rather than looking forward.
Some of these types of trials have been conducted on the effects of electromagnetic waves. But the one study that could settle the issue—a randomized trial of humans exposed to radio waves—would be unethical to conduct. If researchers suspect that radio waves may harm participants, it wouldn’t be right to put them at risk for the sake of science. And now that the debate around 5G has polarized into factions of believers and non-believers, it’s become more and more difficult to trust the motivations of researchers and the work that does exist.
When a study comes out showing limited effects of cell phone radiation, skeptical readers will argue they aren’t well-designed to mimic actual human cell phone use. (Melnick, for example, says that when cell phones are tested for the energy they emit, the phone isn’t directly being held up to the testing fluid the way we hold them up to our ears.)
On the flip side, it’s not clear that scientists will ever be able to give naysayers an acceptable response to those criticisms. When I spoke with Grimes, he drew a parallel between people who cling to fears of 5G and conspiracy theorists. Conspiracy theories, he says, tend to have little to do with the actual facts, and more to do with the person who believes them. Presenting contrary evidence to a believer means they will likely only dig their heels in.
That massive companies and nations are so gung-ho about 5G can make it easy to distrust the motivations behind research into the technology. One thing that makes people worried is when they feel someone is hiding something, says Shannon Brownlee, a former journalist and vice president of the Lown Institute, a non-profit health care think tank in Massachusetts. “Unfortunately, that’s not an unreasonable worry,” she says. Lots of industries have hidden or ignored the harms of their products as long as they could: Take Big Tobacco’s dismissal that cigarettes cause lung cancer, or General Motors’ initial refusal to study the adverse effects of tetraethyl lead, a gas additive.
These errors of the past make it easier for skeptics to raise their eyebrows at the coming 5G revolution. Both the US government and big tech have a vested interest in deploying 5G. There have been whispers in Washington of a geopolitical race, primarily against China, to fully deploy 5G first; although the White House denies that it feels any political pressure to win the telecoms race, the FCC has made it easier for telecom companies to install 5G infrastructure, even though individual cities often aren’t thrilled about doing so. All these factors foster an atmosphere of distrust.
There is still a need for scientists to study the long-term effects of 5G. Just because it should be safe doesn’t mean it is—and at the moment, we don’t have any data on the long-term effects of living in a 5G world. “To say something is safe without evidence makes no sense,” says Melnick. But with both sides so sure they’re right, science is losing its power to objectively inform the conversation.
According to its website, the National Toxicology Program is following up on its studies. It’s reviewing existing literature on 5G radio waves, and developing better chambers to study animal models in weeks, rather than years.
It’s not clear how long it will take for these experiments to get underway. In the meantime, it seems 5G is likely as safe as any other cell phone technology—but that shouldn’t preclude more research.