News about the health risks from use of wireless headsets first
went viral in 2016 (see below). This story has gone viral again at this time for the following four reasons:

  • In the past year, two major studies found conclusive
    evidence that microwave radiation caused cancer in rats. These studies conducted
    by the National
    Toxicology Program
    in the U.S. and the Ramazzini
    in Italy received worldwide media coverage.
  • The proliferation of new cell towers and antennas in
    preparation for the deployment of 5G,
    fifth generation cellular technology
    , has stimulated many people to seek
    out information about the health effects from exposure to the radiation these
    antennas emit on a 24-7 basis in their neighborhoods.
  • Many more people now realize we cannot trust governments to
    protect us from environmental toxins. Industry
    has too much influence over government regulatory agencies
    , and
    governments have conflicts of interest because the telecom industry pays
    governments substantial taxes and fees.
  • Apple announced that it is taking orders for a new version of its wireless headset, AirPods (aka AirPods 2). 

For some Bluetooth devices like Apple’s AirPods, the Specific
Absorption Rate
(SAR), a measure of the body’s maximum exposure to microwave
radiation, exceeds that of many
smart phones. Moreover, the cumulative exposure to radiation from wireless
headsets may be substantial since many users keep these devices on their head for hours at a time and use them to listen to music or podcasts.
I have identified only two small studies that examined the
short-term effects on hearing from exposure to Bluetooth, the communications
standard use in AirPods and other wireless headsets (see below). The health
effects from long-term exposure to this type of microwave radiation have not
been studied.
The FCC minimum exposure levels were adopted in 1996 based
largely upon recommendations from industry-funded scientists and engineers. The
guidelines were designed only to protect us from short-term heating risks. We now
have hundreds of studies that show harmful biologic and health effects from
long-term exposure to low levels of microwave radiation that do not involve
heating. The guidelines need to be updated to protect us from these effects.
Although there is no consensus regarding a safe level of exposure
to microwave radiation, most scientists who have published research on the
effects of this radiation agree that the current exposure limits are much too
permissive. In fact, more than 240 scientists from 42 nations who have
published peer-reviewed research on electromagnetic fields and biology or
health totaling over 2,000 papers in professional journals have signed the International
EMF Scientist Appeal
which calls for stronger exposure limits and health warnings. 
Most wireless safety tips recommend the use of wired headsets or hands-free use of smart phones and other electronic devices instead of wireless headsets.
Some Recent News Stories
Are wireless earbuds dangerous? Experts warn that Apple’s
AirPods could send an electromagnetic field through your brain
Natalie Rahhal, Daily Mail, Updated March 12, 2019

Scientists warn wireless, Bluetooth devices may carry cancer risk

Healio: Hematology/Oncology Today, March 13, 2019
Are Bluetooth Headphones Dangerous? Here’s What
Experts Think
Julia Ries, Healthline, March 24, 2019 
Controversy surrounding safety of
wireless earphones: News Focus 2 with Prof. Joel Moskowitz
Morning, tbs eFM (Seoul, Korea), March 25, 2019 (10 minute audio)

December 13, 2016

Apple announced today that AirPods can be ordered online and will be available in stores next week. The wireless earbuds will be available in limited quantities in more than 100 countries and territories.

Apple originally planned to ship AirPods in October and has not explained the reason for the delay. The Wall Street Journal reported that the delay was due to problems with the Bluetooth wireless technology employed by this device.

September 12, 2016

Apple’s new AirPods are
wireless earbuds that employ Bluetooth technology to communicate
with your smart phone, laptop, or smart watch. 

According to Apple, “After a
simple one-tap setup, AirPods are automatically on and always connected.”

The Specific Absorption Rate (SAR) for the AirPods

The left AirPod emits Bluetooth microwave
radiation in the 2.402 – 2.480 GHz frequency range to communicate with a smart phone or other wireless device. The Specific Absorption Rate (or SAR) of the AirPod is 0.466 watts per kilogram (averaged over 1 gram).
(1)  For more information about the SAR see my post on the iPhone 7.

If one uses the AirPods many hours a day, the cumulative exposure to the brain from this microwave radiation could be substantial. 

According to EE Times, the left AirPod communicates with the right AirPod using a different technology, “near field magnetic induction (NFMI).”

MORE INFO HERE  “Evaluation of the NTP and Ramazzini Studies,” BERENIS Newsletter, November 2018.

Although there is a substantial research literature on the health risks of exposure to magnetic fields, I am not aware of any biologic research that examines NFMI. Hence, this post focuses on the risks to the brain from exposure to Bluetooth radiation. 

Is Bluetooth safe?

The wireless industry
argues that devices that use Bluetooth are safe because the microwave
radiation emitted by such devices is low compared to FCC guidelines. The
FCC requires the SAR to be 1.6 watts per kilogram or less.

More than 240 scientists who have published research on electromagnetic
radiation safety believe that current national and international guidelines for exposure to radio frequency radiation are inadequate to protect
human health (see the 
International EMF Scientist Appeal).

I could find only two peer-reviewed studies that have examined the effects of exposure to Bluetooth radiation. The studies which employed small samples evaluated the effects of brief exposure to Bluetooth radiation on the auditory system. (2) Given the study limitations, the absence of significant effects is not surprising. These studies do not provide the basis to argue that long-term exposure to Bluetooth radiation is safe.

Low-intensity microwave radiation can open the blood-brain barrier

In 1975, Allan Frey published a paper in the Annals of the New York Academy of Sciences which reported that exposure to low intensity microwave radiation could open the blood-brain barrier in rats. Moreover, pulsed radio frequency waves (like Bluetooth) were more likely to produce this effect than continuous waves. (3)

The blood-brain barrier is a special layer of cells in the brain that prevents chemical toxins in the blood system from reaching the brain. Breaching this barrier could potentially lead to neurodevelopmental and neurodegenerative diseases and brain cancer.

More than a dozen peer-reviewed studies have replicated Frey’s findingsexposure to low intensity microwave radiation can open the blood-brain barrier (see links below). (3)  

The effect of
microwave radiation on the blood-brain barrier is nonlinear—it occurs with
low intensity exposures but not at higher intensity exposures.

Although other published studies have failed to find the blood-brain barrier effect, these studies tended to use higher intensity exposures or employed small samples.


We may not be certain of the long-term risks of using Bluetooth devices, but why would anyone insert microwave-emitting
devices in their ears near their brain when there are safer ways to use a cell
I recommend
the use of corded headsets or hands-free use of cell phones, not wireless earbuds. Moreover, one should never keep a cell phone next to your body,
especially during a phone call, but also whenever the phone is powered on. For additional tips on how to reduce your exposure to wireless radiation see

News coverage

In the past few days, numerous news stories have appeared citing industry-affiliated scientists who claim that AirPods are safe. Nonetheless, a few news reports have addressed the potential health risks from using AirPods:

Since the stories in the Daily Mail and CNN were posted on September 8, over two dozen online news stories have appeared that discuss the potential health risks from the microwave radiation emitted by AirPods.
(1) UL
Verification Services, Inc. SAR Evaluation Report for Wireless Headset. FCC ID:
BCG-A1523. Model Name: A1523. Report Number: 16U23784-S6V1. Issue Date: 8/30/2016.
Fremont, CA.

(2) Peer-reviewed studies which reported on the effects of brief exposure to Bluetooth radiation:

Mandalà M, Colletti V, Sacchetto L, Manganotti P, Ramat S,
Marcocci A, Colletti L. Effect of Bluetooth headset and mobile phone
electromagnetic fields on the human auditory nerve. Laryngoscope. 2014

Balachandran R, Prepageran N, Rahmat O, Zulkiflee AB, Hufaida
KS. Effects of Bluetooth device electromagnetic field on hearing: pilot study.
J Laryngol Otol. 2012 Apr;126(4):345-8.

(3) Peer-reviewed studies which reported opening of the blood-brain barrier from exposure to low-intensity microwave radiation:

Tang J, Zhang
Y, Yang L, Chen Q, Tan L, Zuo S, Feng H, Chen Z, Zhu G. Exposure to 900MHz
electromagnetic fields activates the mkp-1/ERK pathway and causes blood-brain
barrier damage and cognitive impairment in rats. Brain Res. 2015 Jan 15.

B, Seyhan N. Effects of radiofrequency radiation exposure on blood-brain
barrier permeability in male and female rats. Electromagn Biol Med. 2011

Nittby H,
Brun A, Eberhardt J, Malmgren L, Persson BR, Salford LG. Increased blood-brain
barrier permeability in mammalian brain 7 days after exposure to the radiation
from a GSM-900 mobile phone. Pathophysiology. 2009 Aug;16(2-3):103-12.

JL, Persson BR, Brun AE, Salford LG, Malmgren LO. Blood-brain barrier
permeability and nerve cell damage in rat brain 14 and 28 days after exposure
to microwaves from GSM mobile phones. Electromagn Biol Med. 2008;27(3):215-29.

IY,  Koch CB, Terenius O,
Roxström-Lindquist K, Malmgren LO, H Sommer W, Salford LG, Persson BR. Exposure
of rat brain to 915 MHz GSM microwaves induces changes in gene expression but
not double stranded DNA breaks or effects on chromatin conformation. Bioelectromagnetics.
2006 May;27(4):295-306.

LG, Brun AE,  Eberhardt JL,  Malmgren L,  Persson BR. Nerve cell damage in mammalian
brain after exposure to microwaves from GSM mobile phones. Environ Health
Perspect. 2003 Jun;111(7):881-3; discussion A408.

D, Joenväärä S, Reivinen J, Kuokka R. Non-thermal activation of the
hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial
cells: molecular mechanism for cancer- and blood-brain barrier-related effects.
Differentiation. 2002 May;70(2-3):120-9.

A, Winters S, Fischer S, Goeke J, Galla HJ, Kullnick U, Ringelstein EB,
Stögbauer F. Electromagnetic fields (1.8 GHz) increase the permeability to
sucrose of the blood-brain barrier in vitro. Bioelectromagnetics. 2000

K, Sommer C, Schmitz B, Mies G, Hossmann KA, Kiessling M, Wiessner C. Effect of
global system for mobile communication (GSM) microwave exposure on blood-brain
barrier permeability in rat. Acta Neuropathol. 1997 Nov;94(5):465-70.

Salford LG,
Brun A, Sturesson K, Eberhardt JL, Persson BR. Permeability of the blood-brain
barrier induced by 915 MHz electromagnetic radiation, continuous wave and
modulated at 8, 16, 50, and 200 Hz. Microsc Res Tech. 1994 Apr 15;27(6):535-42.

Persson BR,
Salford LG, Brun A, Eberhardt JL, Malmgren L. Increased permeability of the
blood-brain barrier induced by magnetic and electromagnetic fields. Ann N Y
Acad Sci. 1992 Mar 31;649:356-8.