Do 5G, Wi-Fi, and Power Lines Cause Cancer?

Two claims travel together online. The first says 5G is a new and stronger kind of radiation. The second says Wi-Fi routers, cell towers, and the power lines outside a house raise cancer risk.

Both can be checked. The answer has two parts. For wireless signals, very large studies have not found a cancer link. For power lines, one finding about childhood leukemia has never been fully explained. That finding is real, and it is covered below rather than skipped.

The National Cancer Institute splits electromagnetic fields, or EMFs, into two groups.

Ionizing radiation covers x-rays, gamma rays, and cosmic rays. It is high frequency and high energy. It can break chemical bonds and damage DNA directly. That damage can change genes and raise cancer risk.

Non-ionizing radiation covers radio waves, microwaves, visible light, and the fields around power lines. It is low frequency and low energy. NCI states that these fields are not known to damage DNA or cells directly.

Every signal in this argument sits in the second group. The numbers are public:

• 2G, 3G, and 4G phones use 0.7 to 2.7 GHz.
• 5G is expected to use frequencies up to 80 GHz.
• Most Wi-Fi runs at 2.4 to 2.5 GHz. Newer bands run at 5, 5.3, or 5.8 GHz.
• Power lines and house wiring make extremely low frequency fields, at or below 300 Hz. NCI calls these ELF-EMFs.

A bigger gigahertz number sounds worse. It does not move 5G out of the non-ionizing group. NCI defines the whole radiofrequency band as 3 kHz up to 300 GHz. A planned ceiling of 80 GHz sits inside that band. So 5G is the same family of energy as radio and microwave, not a new one.

NCI names a single biological effect of radiofrequency energy that ordinary users would meet. The tissue right where a phone is held warms slightly. That means the ear and the side of the head. The warming is not enough to raise core body temperature by a measurable amount. NCI adds that no other dangerous effects on the body are clearly established.

Absorbed energy is measured as the specific absorption rate, or SAR. SAR is stated in watts per kilogram of body weight. It drops very fast as the source moves away from you. The Federal Communications Commission publishes SAR values for phones sold in the past year or two. You can look yours up with the FCC ID number printed on the phone or listed in its settings.

Four large studies dominate this field. None of them found the link the claim describes.

• COSMOS followed 264,574 people in five countries, with a median follow-up of just over seven years. Total call time was not linked to glioma, meningioma, or acoustic neuroma. Neither were the heaviest users or people with 15 or more years of use.
• The Danish cohort study matched billing records for more than 358,000 subscribers to the Danish Cancer Registry. It found no link, even at 13 or more years of use.
• The Million Women Study found no link with glioma or meningioma. An early signal for acoustic neuroma faded once the group was followed for longer.
• Interphone, the largest case-control study, ran across 13 countries. Most analyses showed no rise in brain or other central nervous system cancers. One analysis did show a small but statistically real rise in glioma among the heaviest talkers. The researchers judged that result inconclusive.

Two studies looked at young people. CEFALO enrolled 352 children with brain tumors diagnosed between ages 7 and 19, matched to 646 healthy peers. MOBI-Kids enrolled 899 people ages 10 to 24 diagnosed between 2010 and 2015, matched to 1,910 young people having appendicitis surgery. Neither found a link with wireless phone use.

There is a second, simpler check. If phones caused brain cancer, brain cancer would be rising. It is not. NCI reports steady rates for adult glioma in the United States, the Nordic countries, and Australia. Rates for childhood brain tumors in the United States held steady from 1993 to 2013. Rates for acoustic neuroma and meningioma in United States adults have been stable since 2009.

Wi-Fi puts out far less radiofrequency energy than a phone held to the head. Both sit far below the exposure guideline of 10 watts per square meter set by the International Commission on Non-Ionizing Radiation Protection.

The United Kingdom's health protection agency ran the largest measurement studies of Wi-Fi in schools. Exposures came in well under the recommended limits. The agency concluded there was no reason why Wi-Fi should not stay in use in schools and other places. A review of the published research found that the few high-quality studies show no biological effects from Wi-Fi exposure.

This is the part that honest coverage should not drop. Pooled studies of childhood leukemia and magnetic fields keep showing a small signal at the very top of the exposure range:

• A pooled analysis of nine studies found a twofold rise in childhood leukemia at exposures of 0.4 microtesla or higher. Under 1% of children reached that level.
• A meta-analysis of 15 studies found a 1.7-fold rise at 0.3 microtesla or higher. A little over 3% of children reached it.
• A pooled analysis of seven newer studies found a 1.4-fold rise at 0.3 microtesla or higher. Fewer than half of 1% of children reached it.

NCI is direct about what this does and does not mean. So few children were highly exposed that the dose-response curve is unstable. The data fit a steady rise in risk, a threshold near 0.3 to 0.4 microtesla, or no real rise at all. No mechanism is known. Animal studies of ELF fields have not shown cancer.

That mix is why IARC classified ELF magnetic fields as "possibly carcinogenic to humans" in 2002. It classified static fields and ELF electric fields as not classifiable at all.

IARC put radiofrequency fields in the same "possibly carcinogenic" group in 2011. The label is easy to misread. It describes how strong the evidence is, not how large a risk is. A verdict of "possibly" means the human evidence is limited and a causal reading cannot be ruled out. It is not a finding of harm. The same logic applies across the common cancer myths people hear most.

Federal agencies have stated their positions plainly. FDA says the weight of scientific evidence has not linked cell phone radiofrequency radiation with any health problem. FCC says no scientific evidence establishes a definite link. CDC says no scientific evidence definitively answers the question. NIEHS says the evidence has not conclusively linked cell phone use with adverse health problems.

None of this is a reason to worry, but the steps are cheap. FDA suggests spending less time on calls, using speaker mode or headphones, and texting instead of talking, though not while driving. It also suggests skipping calls when the signal is weak, because a weak signal makes a phone raise its transmit power. Bluetooth earbuds transmit at power levels 10 to 400 times lower than a phone. Magnetic fields from household appliances fall off sharply about a foot away.

If your goal is a real reduction in cancer risk, the proven indoor hazard is a different one: radon gas seeping in from the soil, which is a leading cause of lung cancer in people who never smoked. The kitchen worry that gets far more attention than it deserves is microwave ovens, which are shielded so well that leakage is barely detectable.

• National Cancer Institute, Electromagnetic Fields and Cancer, reviewed May 30, 2022; accessed August 6, 2026
• National Cancer Institute, Cell Phones and Cancer Risk, reviewed April 4, 2024; accessed August 6, 2026
• U.S. Food and Drug Administration, Do Cell Phones Pose a Health Hazard?, content current as of May 13, 2021; accessed August 6, 2026