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https://ntp.niehs.nih.gov/go/cellphone

Cell Phone Radio Frequency Radiation

Final reports from the rat and mouse studies, plus the press release and fact sheet, are now available.
Cell phone

Research Overview

Status: Completed
Substances: Cell Phone Radiation: GSM, Cell Phone Radiation: CDMA
Nominated: May 1999

Background Information

Cell phones are currently used by 95% of American adults. The U.S. Food and Drug Administration (FDA) nominated radio frequency radiation (RFR) used by cell phones for an NTP study because of widespread public use of cell phones and limited knowledge about potential health effects from long-term exposure.

NTP Studies & Findings

NTP conducted toxicology studies in rats and mice to help clarify potential health hazards, including cancer risk, from exposure to RFR like that used in 2G and 3G cell phones which operate within a range of frequencies from about 700 – 2700 megahertz (MHz).

What did the studies find?

The NTP studies found that high exposure to RFR (900 MHz) used by cell phones was associated with:

  • Clear evidence of tumors in the hearts of male rats. The tumors were malignant schwannomas.
  • Some evidence of tumors in the brains of male rats. The tumors were malignant gliomas.
  • Some evidence of tumors in the adrenal glands of male rats. The tumors were benign, malignant, or complex combined pheochromocytoma.

It was unclear if tumors observed in the studies were associated with exposure to RFR in female rats (900 MHz) and male and female mice (1900MHz). This is also known as equivocal evidence.

The final conclusions represent the consensus between NTP and a panel of external scientific experts who thoroughly reviewed the draft NTP technical reports at a public meeting in March 2018.

The results are based on NTP’s four categories of evidence that a substance may cause cancer: clear evidence (highest), some evidence, equivocal evidence, no evidence (lowest).

What are NTP’s future plans for studying cell phone RFR and 5G wireless technology?

5G is currently emerging and will eventually overtake the existing 2G, 3G, and 4G technology. In the meantime, consumers will continue to be exposed to RFR from these sources in the 700-2700 MHz range. As the 5G network is implemented, some of the signals will use the same lower frequencies as the older technology previously studied by NTP. Additionally, concern has been raised because the 5G network will also use higher frequencies, up to 60,000 MHz, thereby exposing wireless consumers to a much broader spectrum of frequencies. The higher frequencies, known as millimeter waves, can rapidly transmit enormous amounts of data with increased network capacity compared to current technologies. Millimeter waves do not travel as far and do not penetrate the body as deep as the wavelengths from the lower frequencies. Millimeter waves are likely to penetrate no deeper than the skin, as opposed to the lower frequencies that have been shown to penetrate at least three to four inches into the human body.

NTP is currently evaluating the existing literature on the higher frequencies intended for use in the 5G network and is working to better understand the biological basis for the cancer findings reported in earlier studies on RFR with 2G and 3G technologies. Additionally, work is ongoing to develop smaller RFR exposure chambers for additional short-term studies that will take weeks and months rather than years. The exposure system is also being designed with the capability of conducting studies with various RFR frequencies and modulations to keep up with the changing technologies in the telecommunications industry.

NTP is also hoping to identify biomarkers of damage from RFR exposure. These would be measurable physical changes that can be seen in shorter periods of time than it takes to develop cancer. Examples could be changes in behavior after exposure or molecular changes that might be predictive of cancer. If scientists can better understand biological changes in animals, they will know more about what to look for in humans.

Informational Resources

Fact Sheet and FAQ
Media Briefing and Interviews
Newsletters
Presentations
Publications
  • Wyde ME, Horn TL, Capstick MH, Ladbury JM, Koepke G, Wilson PF, Kissling GE, Stout MD, Kuster N, Melnick RL, Gauger J, Bucher JR, McCormick DL. Effect of cell phone radiofrequency radiation on body temperature in rodents: Pilot studies of the National Toxicology Program's reverberation chamber exposure system. Bioelectromagnetics. 2018; 39:190-199 https://doi.org/10.1002/bem.22116
  • Capstick MH, Kuehn S, Berdinas-Torres V, Gong Y, Wilson PF, Ladbury JM, Koepke G, McCormick DL, Gauger J, Melnick RL, Kuster N. A radio frequency radiation exposure system for rodents based on reverberation chambers. IEEE Trans Electromagn Compat. 2017; 59(4):1041-1052 https://doi.org/10.1109/TEMC.2017.2649885
  • Gong Y, Capstick MH, Kuehn S, Wilson PF, Ladbury JM, Koepke G, McCormick DL, Melnick R, Kuster N. Life-time dosimetric assessment for mice and rats exposed in reverberation chambers for the two-year NTP cancer bioassay study on cell phone radiation. IEEE Trans Electromagn Compat. 2017; 59(6):1798-1808 https://doi.org/10.1109/TEMC.2017.2665039
  • Wyde M, Cesta M, Blystone C, Elmore S, Foster P, Hooth M, Kissling G, Malarkey D, Sills R, Stout M, Walker N, Witt K, Wolfe M, Bucher J. Report of partial findings from the National Toxicology Program carcinogenesis studies of cell phone radiofrequency radiation in Hsd: Sprage Dawley SD rats (whole body exposure). BioRxiv 055699 [Preprint] May 26, 2016 (modified Feb 01, 2018). https://doi.org/10.1101/055699
Photos of the Radiofrequency Radiation Research Facility

Click on the thumbnail to see a larger version of the photo.

Internal view of open reverberation chamber External view of reverberation chambers Internal view of empty open reverberation chamber

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