Is 5G Dangerous? What the Science Says About Radio Waves, Cell Towers, and Cancer Risk

As wireless carriers began building 5G networks in the late 2010s, a wave of opposition followed. Residents in many communities objected to small cell antennas being installed on utility poles near homes and schools. In California, state legislation to streamline small cell installation drew opposition from cities and health activists and was vetoed in 2017. Online, claims spread that 5G causes cancer, weakens immunity, or harms wildlife, and during the COVID-19 pandemic some claims even linked 5G to the virus, leading to arson attacks on cell towers in several countries.

Concerns about new technologies are understandable, and questions about radiofrequency exposure have been studied for decades. This article explains what 5G is, how its radio waves differ from other forms of radiation, what major scientific reviews have found, where real uncertainties lie, how exposure limits are set, and what people concerned about exposure can practically do.

What 5G Is

5G is the fifth generation of cellular network technology. Like earlier generations, it uses radio waves to carry data between phones and antennas. What changed is mainly speed, capacity, and responsiveness, achieved by using a wider range of frequencies and new antenna technologies.

5G networks operate in three broad frequency ranges. Low-band 5G uses frequencies below about 1 gigahertz, similar to earlier networks, and covers large areas. Mid-band 5G, roughly 1 to 6 gigahertz, offers a balance of coverage and speed and carries much of today’s 5G traffic. High-band 5G, often called millimeter wave, uses frequencies of about 24 gigahertz and above, offering very high speeds over short distances. Because high frequencies travel shorter distances and are blocked easily by walls and even leaves, millimeter wave networks require many more antennas, often small cells mounted on poles and buildings, which is what made 5G infrastructure so visible in neighborhoods.

Ionizing Versus Non-Ionizing Radiation

The word “radiation” covers a wide spectrum of energy. At the high-energy end, ultraviolet light, X-rays, and gamma rays are ionizing: they carry enough energy to knock electrons out of atoms, break chemical bonds, and damage DNA directly, which is how they can cause cancer. At the lower-energy end, radio waves, microwaves, and visible light are non-ionizing. Radiofrequency energy used for cell phones, Wi-Fi, radio, and television, including all 5G frequencies, falls well below the ionizing range.

The main established biological effect of radiofrequency energy at high levels is heating, the principle behind microwave ovens, which operate at much higher power in an enclosed space. International exposure limits are designed to keep heating well below levels that could cause harm. Research has also examined whether radiofrequency exposure below heating levels could have other biological effects; this is where scientific debate has focused.

A common misconception is that higher-frequency 5G is more dangerous because it is “stronger.” In fact, higher radio frequencies penetrate the body less. The World Health Organization notes that as frequency increases, penetration into body tissues decreases, so absorption of millimeter wave energy is confined mostly to the skin surface. The WHO also states that, to date, and after much research, no adverse health effect has been causally linked with exposure to wireless technologies, provided exposures remain below international guideline limits.

What the Evidence Shows on Cancer

The 2011 IARC classification

In May 2011, the International Agency for Research on Cancer classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B). The working group based this mainly on limited evidence from some case-control studies suggesting an increased risk of glioma, a type of brain tumor, and acoustic neuroma among the heaviest mobile phone users. Group 2B is a category for agents where evidence is limited and chance, bias, or confounding cannot be ruled out; it also includes items such as aloe vera extract and pickled vegetables in some forms. The classification signaled the need for more research rather than a finding that radiofrequency fields cause cancer.

The WHO-commissioned systematic review, 2024

Since 2011, many more and larger studies have been published. In preparing an updated health assessment, the World Health Organization commissioned systematic reviews of the evidence. The first, published in Environment International in 2024 and led by Ken Karipidis of the Australian Radiation Protection and Nuclear Safety Agency, screened more than 5,000 studies published between 1994 and 2022 and included 63 in its analysis.

It found that mobile phone use was not associated with increased risk of glioma (meta-relative risk 1.01), meningioma (0.92), acoustic neuroma (1.03), pituitary tumors (0.81), salivary gland tumors (0.91), or brain tumors in children, adolescents, and young adults (1.06). Long-term use of ten years or more was also not significantly associated with glioma, meningioma, or acoustic neuroma. Importantly for 5G debates, exposure from fixed-site transmitters, meaning broadcast antennas and cell phone base stations, was not associated with childhood leukemia or pediatric brain tumor risk.

A second review published in 2025 examined other cancers and found that mobile phone use was not associated with leukemia, non-Hodgkin lymphoma, or thyroid cancer, including with long-term use.

The 2018 National Toxicology Program rat study

The most-cited study suggesting possible harm is a large animal study by the U.S. National Toxicology Program, completed in 2018. Rats and mice were exposed to radiofrequency radiation of the type used in 2G and 3G phones, across their whole bodies, for about nine hours a day for up to two years. NTP reported clear evidence of tumors in the hearts of male rats, specifically malignant schwannomas, and some evidence of tumors in the brain and adrenal glands of male rats, but not in female rats or mice. The exposure levels were higher than people typically experience, even with heavy phone use, and the exposed male rats unexpectedly lived longer than unexposed controls.

The study did not test 5G frequencies, and NTP emphasized that its findings should not be directly extrapolated to human phone use. Regulators in the United States and elsewhere reviewed the findings and did not change exposure limits, though the study remains a reference point for those calling for more precaution.

Population trends

Another line of evidence comes from cancer statistics. Mobile phone use grew from rare to nearly universal over three decades. If phones caused a substantial increase in brain cancer, rates would be expected to rise. Studies in several countries have generally found no rise in brain cancer incidence consistent with the growth of mobile phone use, as the authors of the WHO review noted.

How Exposure Limits Work

International exposure guidelines are published by the International Commission on Non-Ionizing Radiation Protection, an independent scientific body recognized by the WHO. ICNIRP’s guidelines, updated in 2020 to address higher frequencies used by 5G, set limits with large safety margins below levels at which established effects such as tissue heating occur. In the United States, the Federal Communications Commission sets exposure limits for phones and transmitters, based on standards adopted in 1996.

The FCC’s limits have been challenged. In 2019, the FCC decided not to change them. In 2021, a federal appeals court ruled that the agency had not adequately explained its decision with respect to evidence on non-cancer effects, long-term exposure, and children, and sent the matter back to the FCC for further explanation. The court did not find that the limits were unsafe; it required a better justification.

Measurement studies in many countries have found that public exposure from cell towers and small cells, including 5G, is generally a small fraction of international limits. Exposure from a phone held against the head is typically much higher than exposure from a nearby tower, because intensity drops sharply with distance from the antenna.

Other Health Claims About 5G

Claim	What the evidence shows
5G causes cancer	Large reviews find no association between mobile phone use or living near transmitters and cancer risk; 5G frequencies are non-ionizing.
5G spread COVID-19 or weakens immunity	False. Viruses cannot travel on radio waves, and COVID-19 spread widely in places without 5G networks.
People can feel 5G (electromagnetic hypersensitivity)	Symptoms people report are real, but double-blind studies have not shown that sufferers can detect actual exposure or that symptoms track exposure.
5G harms sleep or fertility	Research on sleep and sperm quality is mixed and mostly concerns phones held close to the body, not towers; no consistent evidence of harm at typical exposures.
5G kills birds and bees	Widely shared stories of mass bird deaths linked to 5G tests were not supported by investigation; research on insects and RF is limited and inconclusive.
Millimeter waves penetrate deep into the body	The opposite: higher frequencies are absorbed mostly in the outer skin layers.

Electromagnetic hypersensitivity deserves a compassionate response. People who report it experience real symptoms such as headaches, fatigue, and difficulty concentrating. In blinded provocation studies, however, participants generally cannot tell whether a signal is on or off, and symptoms occur regardless of actual exposure. Health authorities recommend that people with these symptoms receive medical evaluation and support, since the symptoms can be disabling whatever their cause.

Why Communities Fight Small Cells

Opposition to 5G infrastructure has not been only about health. Small cell antennas, mounted on streetlights and utility poles, have raised concerns about aesthetics, property values, local control over public rights-of-way, and the speed with which carriers sought permits. In 2017, California lawmakers passed a bill that would have limited cities’ authority over small cell permits and fees; Governor Jerry Brown vetoed it, saying local governments should retain more control. In 2018, the FCC adopted rules limiting the fees and time local governments could take to process small cell applications nationwide, which many cities challenged in court.

Federal law also limits health-based objections. The Telecommunications Act of 1996 prevents state and local governments from regulating the placement of wireless facilities on the basis of the environmental effects of radiofrequency emissions, as long as facilities comply with FCC exposure limits. As a result, local disputes over 5G siting tend to focus on design, location, notice, and fees rather than on health.

How to Reduce Your Exposure

For people who want to reduce radiofrequency exposure as a precaution, the most effective steps involve personal devices rather than towers, because a phone near the body delivers far more exposure than a distant antenna. The U.S. National Cancer Institute notes that people concerned about exposure can reduce it in simple ways.

Use speakerphone or wired or wireless earphones to keep the phone away from your head.

Text more, talk less when convenient.

Avoid long calls when the signal is weak. Phones increase transmission power when the connection is poor.

Keep the phone off your body when not in use, for example in a bag rather than a pocket, and away from the bed at night.

Limit screen time for children for reasons beyond radiofrequency exposure, including sleep, attention, and physical activity, which pediatric organizations emphasize.

These steps are low cost and reasonable for anyone who wants to minimize exposure, even though the evidence does not show harm at typical levels.

A Brief History of Radiofrequency Health Concerns

Public worry about invisible electromagnetic fields long predates 5G. In the 1980s and 1990s, concern focused on power lines and childhood leukemia, prompting decades of research. As mobile phones spread in the 1990s, attention turned to radiofrequency energy from handsets held against the head. Large international studies followed, including the multinational Interphone case-control study, whose mixed results, with some signals among the heaviest users alongside patterns suggesting recall bias, contributed to IARC’s cautious 2011 classification. Prospective cohort studies in Europe that followed large numbers of people over time generally did not find increased brain tumor risk.

Each new wireless technology, from Wi-Fi in schools to smart meters and now 5G, has brought a new round of public concern. Researchers have noted that exposures from these newer technologies are typically lower than from mobile phones held to the head, which remain the largest source of radiofrequency exposure for most people.

How Exposure Is Measured

For phones and other devices used close to the body, regulators measure the specific absorption rate, or SAR, which is the rate at which the body absorbs radiofrequency energy, expressed in watts per kilogram. Phones must stay below SAR limits under worst-case testing conditions, and in everyday use they often transmit at lower power. At higher frequencies, above about 6 gigahertz, where energy is absorbed near the surface, limits are expressed in terms of power density, the energy per area reaching the skin.

For towers and small cells, measurements of power density in publicly accessible areas compare real-world exposure with guideline limits. Because intensity falls rapidly with distance, levels a few meters from an antenna are usually far lower than directly in front of it, and antennas are typically mounted at heights that keep the public outside the areas where limits could be approached.

Understanding Risk Categories

Hazard classifications like IARC’s are often misunderstood. They describe the strength of evidence that something can cause cancer under some circumstances, not how much risk it poses at typical exposures. Radiofrequency fields in Group 2B share that category with agents for which evidence is limited, which is different from established carcinogens in Group 1, such as tobacco smoke. Risk assessment, which considers how much exposure people actually receive, is a separate step carried out by health agencies. For radiofrequency fields, those assessments have concluded that exposures below international limits have not been shown to cause harm.

5G Near Schools and Homes

Parents often ask whether children should be protected from antennas near schools. Exposure measurements around schools and homes near base stations have generally found levels far below international limits, and the WHO-commissioned review found no association between residential proximity to transmitters and childhood leukemia or brain tumors. Children’s greatest radiofrequency exposure usually comes from their own devices held close to the body, which is why practical guidance focuses on device habits.

Some schools and municipalities have nonetheless adopted precautionary policies, such as restricting antenna placement near schools or encouraging wired internet connections in classrooms. These policies reflect community preferences and precaution rather than demonstrated harm.

Questions to Ask Your Local Government

Residents concerned about a planned small cell or tower can ask practical questions that local officials can answer. Where exactly will the antenna be placed, and how high? What is the expected exposure level at nearby homes and public areas compared with FCC limits, and will measurements be made after installation? What design standards apply to reduce visual impact? What notice and comment opportunities exist before approval? How can residents report concerns after installation? Because federal law limits local decisions based on radiofrequency emissions that comply with FCC limits, the most productive local discussions usually focus on location, design, and transparency.

Key Terms

Radiofrequency (RF) radiation: Non-ionizing electromagnetic energy used for radio, TV, cellular, and Wi-Fi communications.

Millimeter wave: High-frequency radio waves, roughly 24 gigahertz and above, used for high-speed short-range 5G.

Small cell: A low-power antenna serving a small area, often mounted on poles or buildings.

Specific absorption rate (SAR): A measure of how much RF energy the body absorbs from a device.

Power density: The amount of RF energy reaching a surface, used for exposure limits at higher frequencies.

What Remains Uncertain

Scientific reviews have been increasingly reassuring, but several questions remain. Long-term data on newer technologies, particularly millimeter wave 5G, are still limited because these networks are relatively new, although the physics of shallow absorption reduces concern. Studies of children’s exposure, which may differ because of thinner skulls and longer lifetime use, continue. Researchers also continue to examine possible non-thermal biological effects reported in some laboratory studies, which have generally not been consistently replicated. The WHO is preparing a comprehensive health risk assessment of radiofrequency fields that will draw on its commissioned reviews.

Continued research and transparent exposure monitoring are reasonable. Claims that 5G is causing widespread harm, however, are not supported by the evidence available today.

Timeline: Wireless Technology and Health Research

Year	Development
1996	FCC adopts current U.S. radiofrequency exposure limits; Telecommunications Act limits local regulation of wireless facilities based on RF emissions
1998	ICNIRP publishes international exposure guidelines
2010	Results of the multinational Interphone study of mobile phones and brain tumors published
2011	IARC classifies RF fields as possibly carcinogenic (Group 2B)
2017	California governor vetoes bill limiting local control over small cells
2018	NTP releases final results of its rat and mouse RF study; FCC adopts small cell rules
2019–2020	5G networks launch widely; ICNIRP updates guidelines for higher frequencies; COVID-related 5G conspiracy theories lead to tower attacks
2021	Federal appeals court requires FCC to better explain its decision to keep RF limits
2024–2025	WHO-commissioned systematic reviews find no association between mobile phone use or transmitter exposure and cancer

Why Some Scientists Still Urge Precaution

Despite reassuring reviews, a minority of scientists and some advocacy groups continue to call for lower exposure limits or precautionary policies. Their arguments include the NTP rat findings, laboratory studies reporting biological effects below heating thresholds, the relatively short time 5G has been deployed, and the 2021 court ruling questioning how the FCC justified its limits. Some also argue that industry funding has influenced research.

Mainstream health agencies respond that laboratory findings of non-thermal effects have not been consistently replicated, that the NTP exposures were far above typical human levels, and that the weight of human evidence has become more reassuring over time. They agree that research should continue and that exposure guidelines should be updated as evidence develops. The practical gap between the two positions is narrower than it might appear: both support continued research, and simple steps to reduce personal exposure are available to anyone who wants them.

How to Read 5G Health Headlines

Health headlines about wireless technology often swing between alarm and dismissal. A few questions help put them in context. Was the study in people, animals, or cells? Animal and cell studies can identify questions but often use exposures and conditions very different from everyday life. How large was the effect, and was it replicated? A single small study rarely changes the overall picture. Does the claim match the physics? For example, assertions that higher-frequency 5G penetrates deeper into the body contradict basic physics. Who funded and published the work, and do independent reviews agree? Systematic reviews by public health agencies weigh many studies together and are more reliable than individual reports.

A Practical Checklist for Families

Use speakerphone or earphones for long calls. Keep phones off the body and out of the bed at night. Avoid long calls when the signal is weak. Encourage children to text or use video calls on a table rather than holding phones to their heads. Set screen time limits for sleep and well-being. If a new antenna is proposed nearby, ask local officials for siting details and expected exposure levels. These steps are simple, inexpensive, and reasonable whatever one’s view of the remaining scientific uncertainties.

Frequently Asked Questions

Does 5G cause cancer?

Current evidence does not show that it does. A large WHO-commissioned review found no association between mobile phone use and brain cancers and no increased childhood cancer risk from living near transmitters. 5G uses non-ionizing radio waves that cannot directly damage DNA.

Is it safe to live near a 5G tower or small cell?

Exposure from towers and small cells is generally a small fraction of international safety limits, and studies of people living near transmitters have not found increased cancer risk. Exposure from your own phone is typically higher.

Why did IARC classify radiofrequency radiation as possibly carcinogenic?

In 2011, IARC cited limited evidence from some studies of heavy mobile phone users. Group 2B indicates limited evidence, not established harm, and larger newer studies have been reassuring.

What did the NTP rat study find?

It found tumors in the hearts of male rats exposed to very high whole-body levels of older 2G and 3G signals for up to two years, but not in female rats or mice. The exposures exceeded typical human exposure, and the study did not test 5G.

Is millimeter wave 5G more dangerous?

No evidence shows that. Higher frequencies penetrate the body less, depositing energy mainly in the outer skin layers, and exposure limits account for this.

Did California ban 5G?

No. In 2017, the governor vetoed a bill that would have limited local control over small cell installations. 5G networks operate throughout California.

References

1. Karipidis K, Baaken D, Loney T, et al. The effect of exposure to radiofrequency fields on cancer risk in the general and working population: A systematic review of human observational studies, Part I: Most researched outcomes. Environment International. 2024;191:108983. PMID 39241333
2. Karipidis K, Baaken D, Loney T, et al. The effect of exposure to radiofrequency fields on cancer risk in the general and working population: A systematic review of human observational studies, Part II: Less researched outcomes. Environment International. 2025;196:109274. PMID 39904670
3. International Agency for Research on Cancer. IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans. Press release No. 208. May 31, 2011. iarc.who.int
4. World Health Organization. Radiation: 5G mobile networks and health. who.int
5. National Toxicology Program. Cell Phone Radio Frequency Radiation. ntp.niehs.nih.gov
6. International Commission on Non-Ionizing Radiation Protection. RF EMF FAQ. icnirp.org
7. National Cancer Institute. Cell Phones and Cancer Risk Fact Sheet. cancer.gov

Last updated: October 1, 2026