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Radiofrequency (RF) Radiation

                                                                                                                                                                                                                       Updated 5/11/23

Radiofrequency (RF) Radiation

Cell phones, radar and radio transmitters, and many other sources expose us all to RF waves, including microwaves (MW). At high levels, tissue heating (thermal) effects are well known and familiar to MW oven users. Overexposure to RF radiation can cause adverse health effects.  At lower levels, RF may disrupt some electronic medical implants like pacemakers and insulin pumps.

International epidemiological surveys show that a small percentage of the global population report non-specific symptoms of electrohypersensitivity including skin reactions, headaches and heart palpitations.  Study of self-reported hypersensitivity to electromagnetic fields in California. | Environmental Health Perspectives | Vol. 110, No. suppl 4

  Scientists agree more research is needed in some areas.


Based on current knowledge, government and science bodies have set RF exposure limits. There is evidence that biological effects do occur below these limits, however it has not been determined whether such exposures cause adverse health effects.


The International Agency for Research on Cancer (IARC) rates RF as a possible carcinogen. What does the IARC mean by “possible”? IARC has sorted over 1,000 chemical, physical, and biological agents into one of four groups based on the scientific evidence. Group 1 is known to cause cancer. This group includes alcoholic drinks and diesel exhaust. Group 2A is probable, including things like red meat consumption. RF is in Group 2B, possible, which also includes things like aloe vera and gasoline. Group 3 is not classifiable due to lack of evidence and includes tea and jet fuel. IARC based placing RF in Group 2B based on some studies linking brain cancers to wireless phone use.

IARC classified RF as possibly carcinogenic


Subsequent animal studies also showed a possible carcinogenic link.  National Toxicology Program study.  However, during the past two decades of huge growth in cell phone use, U.S. brain cancer rates have remained fairly steady. National Cancer Institute National Trends in New Cancer Rates.



The frequency of an RF signal is usually expressed in terms of a unit called the hertz (Hz). One Hz equals one cycle per second. One megahertz (MHz) equals one million cycles per second. Radiofrequency falls between 300 gigahertz (GHz) and 3 kilohertz (kHz). Within this frequency range, there are:


Microwaves in the 300 GHz to 300 MHz frequency range. Sources of microwaves are some mobile/cell phones, microwave ovens, cordless phones, motion detectors, long-distance telecommunications, radar, and Wi-Fi.  Microwaves can cause damage through heating of body tissue.

Radio Waves in the 300 MHz to 3 kHz frequency range.  Naturally occurring radio waves are made by lightning or by astronomical objects. Human produced radio waves are used for mobile/cell phones, smart meters, televisions, FM and AM radios, shortwave radios, CB radios, cordless phones, broadcasting, radar and other navigation systems, satellite communication, computer networks and other applications.

Smart Meters

Smart Meters are deployed in many places to help create a new "smart grid" of utility services that can respond quickly, be more efficient, and reduce costs. Smart meters work by transmitting RF data. Some people are concerned about possible health effects of these RF signals as smart meters become wide spread. Key findings of a 2011 study Health Impacts of Radio Frequency from Smart Meters by the California Council of Science and Technology include:

·         Smart meters give much lower levels of RF than common household devices like cell phones and MW ovens.

·         FCC rules protect against known thermal health impacts of common household devices and smart meters.


If exposure to smart meters is a concern, opt to not use them in your home.  Duke Energy has an Opt Out Program for their utility meters. 

Smart Meters -  What We Know Federal Communications Commission (FCC)

5G Cellular Networks

5G differs from prior wireless networks in a few ways. Some 5G cell phones use the same roughly 600 MHz to 900 MHz range as older networks. However, most 5G networks use the part of the spectrum above 3 GHz (3000 MHz). These higher frequencies carry more data but do not go as far in buildings, plants, or people. GHz waves only enter the surface of the skin, compared to a centimeter or so for MHz waves. It also means that 5G GHz networks need many smaller, lower power base stations compared to older networks. 5G networks use different modulation, which is how the data is packaged in the cell signal. Some scientists think that this new modulation may cause unknown human health effects.

There are limited studies on health-related effects of millimeter waves. The results of most studies in the literature are of uncertain relevance to health. Many have small samples of subjects, and many lack elementary precautions to ensure reliability. Well-done studies to identify biological effects of millimeter waves of potential health significance are warranted. The scientific evidence on which to base safety recommendations is limited resulting in the two conflicting theoretical evaluations of risk below:

Key findings of the 2020 report on Health and Safety of 5G Wireless Networks by the IEEE Committee on Man and Radiation include:

•         Unlike current MHz fields, the higher frequency GHZ signals do not penetrate beyond the outer layers of skin and thus do not expose deeper tissues directly.

•         Overall exposure levels will not change much and will come mostly from our personal wireless devices (as they do now).

•         Exposure levels in public spaces will stay well below the limits set by scientific experts.

•         So long as exposures remain below those limits, current research does not show that there will be any adverse thermal effects, including from 5G.

Findings from Reviews on Environmental Health recommend more research into the long-term effects of exposure to the higher 5G frequencies, new modulations, and proximity to 5G base stations.

Occupational Exposure

Many municipal and utility workers will need to work near 5G sources. Each employer should have an exposure control plan or safety plan that outlines the types of controls for those working near cellular stations. Controls such as locking-out the transmitter (that is, removing the RF while work is performed); proper training, procedures, and signage; and monitoring RF levels while working will be key. Generation Gap (aiha.org)

Minimize Your Risk

The American Academy of Pediatrics (AAP) recommends limiting cell phone use for children and teenagers. The AAP also reminds parents that cell phones are not toys and are not recommended for infants and toddlers to play with. If you have concerns about RF fields, the AAP offers the following easy tips for reducing exposure:

• Do not talk on the phone or text while driving. This increases the risk of automobile crashes.

• Exercise caution when using a phone or texting while walking or performing other activities.

• Use text messaging when possible and use cell phones in speaker mode or with the use of hands-free kits.

• When talking on the cell phone, try holding it an inch or more away from your head.

• Make only short or essential calls on cell phones.

• Avoid carrying your phone against the body like in a pocket, sock, or bra.

• If you plan to watch a movie on your device, download it first, then switch to airplane mode while you watch in order to avoid unnecessary radiation exposure.

• Keep an eye on your signal strength (i.e. how many bars you have). The weaker your cell signal, the harder your phone has to work and the more radiation it gives off. It's better to wait until you have a stronger signal before using your device.

• Avoid making calls in cars, elevators, buses. Cell phone works harder to get a signal through metal, increasing its power.

• Remember that cell phones are not toys or teething items.


US Regulations

The Federal Communications Commission (FCC) is required to assess the health effects of RF from the transmitters they regulate. Groups like ANSI, IEEE, and NCRP have set RF exposure limits.  In 1996, the FCC adopted the NCRP's limits for field strength and power density from 300 kHz to 100 GHz.  In addition, the FCC adopted the ANSI/IEEE specific absorption rate (SAR) limits for devices that emit close to the body.

The FCC requires that wireless communication devices sold in the U.S. stay within these RF exposure limits. The FCC also licenses sites that emit RF, such as radio and television broadcast stations. The FCC reviews such sites to make sure they comply with the limits when those sites apply for construction, modify a facility, or renew their license.

FCC Radiofrequency Safety

FCC Radiofrequency Guidelines for Cellular and PCS Sites

FCC Review of RF Exposure Policies

FDA Cell Phone Facts Questions and Answers




For more information and additional resources, contact: [email protected] 



NC Radiation Protection Section

1645 Mail Service Center

Raleigh, NC  27699-1600