Radiofrequency (RF) Radiation

Radiofrequency (RF) radiation is a type of radiation used in many types of modern technology. Common uses include sending signals through the air via AM/FM radio, cell phones and cell towers, Wi-Fi, Bluetooth devices, and other wireless communication systems. RF radiation is also used by microwaves to heat food.

Because people are regularly exposed to RF radiation in daily life, some might worry that long-term exposure might affect their health, including raising their cancer risk. Learning what research shows can help you separate facts from fears and make informed decisions.

The electromagnetic spectrum

Types of radiation exist along a range from very low-energy (low-frequency) radiation to very high-energy (high-frequency) radiation. This range is called the electromagnetic spectrum.

Examples of high-energy radiation include x-rays and gamma rays, as well as some higher energy ultraviolet (UV) rays. These are forms of ionizing radiation, which have enough energy to remove an electron from (ionize) an atom. This can damage the DNA (genes) inside cells, which can sometimes lead to cancer.

What is radiofrequency (RF) radiation?

Radiofrequency (RF) radiation includes radio waves and microwaves. It falls at the low-energy end of the electromagnetic spectrum. It is a type of non-ionizing radiation, meaning it doesn’t have enough energy to remove electrons from atoms. RF radiation has less energy than other types of non-ionizing radiation, such as infrared and visible light, but more energy than extremely low-frequency (ELF) radiation.

If the body absorbs large amounts of RF radiation, it can produce heat. In rare cases, this can lead to burns or tissue damage.

Unlike ionizing radiation, RF radiation is not thought to cause cancer by damaging the DNA in cells. However, some researchers have asked whether some forms of non-ionizing radiation could affect cells in other ways that might lead to cancer.

Does RF radiation cause cancer?

Concerns that RF radiation might cause health problems, including cancer, have been around for many years.

What do expert agencies say?

In general, the American Cancer Society (ACS) does not determine whether something should be considered a carcinogen (something that can cause cancer). Instead, ACS looks to other respected organizations for help with this.

Based on animal and human evidence, several expert agencies have evaluated the cancer-causing potential of RF radiation:

• The International Agency for Research on Cancer (IARC) classifies RF radiation as “possibly carcinogenic to humans,” based on limited evidence of a possible increase in risk for brain tumors among cell phone users, and inadequate evidence for other types of cancer. An IARC advisory group has suggested this topic as a high priority for reevaluation in the future.
• The US National Toxicology Program (NTP) has not included RF radiation in its Report on Carcinogens, which lists exposures that are known to be or reasonably anticipated to be human carcinogens. Some NTP lab studies in rats suggested a link between cancer and high levels of RF radiation, but other animal studies have not shown such a link.
• The US Food and Drug Administration (FDA) has stated that current research doesn’t provide enough evidence to show that exposure to RF radiation directly causes tumor formation.
• The US Federal Communications Commission (FCC) has stated there is no scientific proof that using wireless devices causes cancer or other illnesses. Experts looking at potential risks agree that more longer-term studies are needed to explore whether current safety standards for RF radiation exposure are adequate.

To learn more about how cancer causes are studied and classified, see How Do We Know What Causes Cancer? and Known and Probable Human Carcinogens.

What do studies show?

Researchers use 2 main types of studies to try to determine if something might cause cancer:

• Lab studies are done using lab animals or cells in lab dishes.
• Studies in people compare groups to see if people with higher exposures are more likely to develop cancer.

Often, neither type of study provides conclusive evidence on its own. Both human and lab-based studies are reviewed when trying to figure out if something causes cancer.

Studies in the lab

RF waves don’t have enough energy to directly damage DNA like ionizing radiation does, so it’s unclear how RF radiation could cause cancer. Some lab studies in animals have suggested links between exposure and certain tumors or biological effects that could affect DNA, but overall, the results are inconclusive.

Large studies of animals have produced mixed results. Some suggest increases in rare tumors, such as certain heart, brain, and adrenal gland tumors, after long-term whole-body RF radiation exposure. But other studies, including re-analyses of earlier research, don’t have the same findings. Many of these studies have limitations that make it hard to know if the results apply to humans, and their interpretation remains debated.

Studies in people

Research on RF radiation exposure through cell phone use and cancer risk has been mixed. A few studies have suggested a possible link, but the vast majority have not. Cell tower radiation and cancer risk has also been studied.

Studies of people with higher workplace exposure to RF radiation have not shown a clear increase in cancer risk. Research has included studies on radar and electronics technicians, those who maintain RF and microwave equipment, utility workers, and multi-worker populations with varying levels of RF exposure. Most of that research has focused on the risk of brain cancer or lymphomas and leukemias. While some studies have identified possible links between RF exposure and those cancers, many other studies have not.

There is limited research on the health effects of Wi-Fi, including its possible link to cancer. However, Wi-Fi devices expose people to very low levels of RF radiation, well below established safety limits, and current evidence does not suggest that Wi-Fi is harmful to health.

How are people exposed to RF radiation?

People can be exposed to RF radiation from both natural and human-made sources.

Natural sources include:

• The sun and outer space
• The atmosphere
• Lightning strikes
• Earth, which gives off infrared radiation, though only tiny amounts are in the RF range

Human-made sources include:

• Radio and television broadcasting signals
• Wireless communication devices, such as cordless telephones, cell phones, cell phone towers, satellite phones, and 2-way radios
• Smart meters
• Radar systems
• Wireless technologies, such as Wi-Fi and Bluetooth devices
• Some medical procedures, such as radiofrequency ablation, which uses heat from RF energy to destroy tumors or tissue
• Industrial equipment, such as machines used to seal or weld polyvinyl chloride (PVC) plastics 
• Microwave ovens
• Millimeter wave scanners, a type of full-body scanner used in some security screenings

Some people may have higher exposure to RF radiation at work. This includes workers who maintain antenna towers and people who use or maintain radar equipment. Higher exposures might also occur in some healthcare workers (such as those working near MRI scanners) and people who work with RF devices, such as plastic sealers, certain types of welding equipment, and induction heaters.

Can I avoid or limit my exposure to RF radiation?

Because sources of RF radiation are so common in the everyday world, there is no way to completely avoid exposure to it. Some ways to lower your exposure include:

• Avoiding jobs with increased exposure
• Limiting the time you spend near appliances, equipment, and other devices (such as Wi-Fi routers) that give off RF radiation
• Limiting the time you spend with a cell phone placed against your ear or close to another part of your body

Where to find more information

Federal Communications Commission (FCC)
Website: www.fcc.gov
Wireless Devices and Health Concerns
RF Safety FAQ

National Cancer Institute (NCI)
Toll-free number: 1-800-422-6237 (1-800-4-CANCER)
Website: www.cancer.gov
Electromagnetic Fields and Cancer

National Institute of Environmental Health Sciences (NIEHS)
Website: www.niehs.nih.gov
Electric & Magnetic Fields