A story began circulating on internet news platforms on Wednesday (March 13) that more than 200 scientists from 40 countries had signed a declaration warning about the dangers to human health posed by Apple Airpods and other wireless headphones. That is incorrect.
No, scientists didn’t sign anything about the dangers of Airpods
The scientist declaration referenced in all the news posts is actually from 2015, and was an appeal to governments to take seriously the potential health threats of the type of non-ionizing radiofrequency radiation emitted by cell phones and other wireless devices. Yes, those include Bluetooth devices, like Airpods. But it’s not that simple. We’ll get to that in a minute.
So what happened here?
The stories published this week were sparked by a Medium post from last Thursday (March 7) that mentioned the declaration, and quoted one of the signees, Jerry Phillips, a professor of biochemistry at the University of Colorado-Colorado Springs.
“My concern for AirPods is that their placement in the ear canal exposes tissues in the head to relatively high levels of radiofrequency radiation,” he told Medium.
We do know cell phones can cause cancer in rats
Cell phones emit non-ionizing radiation while communicating with cell towers. In 2018, after years of research, US scientists released the peer-reviewed results of a pair of federally-funded studies finding that this type of radiation could cause cancer in rats.
That was major news. It substantially changed the debate on whether cell phone use is a cancer risk. Up until that point, the federal government and device manufacturers operated on the assumption that cell phones cannot by their very nature cause cancer, because they emit non-ionizing radiation. Whereas ionizing radiation—the kind associated with, for example, x-rays, CT scans, and nuclear power plants—definitely causes cancer (in humans and rats and other mammals) at high enough doses, non-ionizing radiation was believed to not emit enough energy to break chemical bonds. That meant it couldn’t damage DNA, and therefore couldn’t lead to the mutations that cause cancer.
But the pair of studies by the US National Toxicology Program found “clear evidence” that exposure to non-ionizing radiation caused heart tumors in male rats, and found “some evidence” that it caused tumors in the brains of male rats. (The NTP uses the labels “clear evidence,” “some evidence,” “equivocal evidence,” and “no evidence” when making conclusions.)
Ronald Melnick, the NTP senior toxicologist who designed the studies in the early 2000s (and who retired from the agency in 2009) said at the time of publication that the reports made it unlikely any future study could conclude with certainty that there is no risk to humans from cell phone use.
Now, the scientific community has to figure out how those findings in lab rats relate to humans—and what doses of radiation pose a threat. So, yes, there are legitimate scientific reasons to be skeptical about the harmlessness of cell phones.
How this relates to this whole Airpod thing
Airpods use Bluetooth technology. Bluetooth (and WiFi) also uses the non-ionizing radiofrequency radiation that cell phones use. But just like we still don’t know what dose of cell phone radiation could be harmful to humans, we still don’t know how much—or even whether—Bluetooth radiation poses a threat.
One thing seems logical: Bluetooth likely delivers a lower dose of radiation than cell phones. Whereas your cell phone has to communicate with a cell tower somewhere, likely some distance away from your device, your Airpods are only communicating the distance between your head and your cell phone. The shorter distance means Bluetooth radiofrequency can function at a much lower power than cell phone radiofrequency. As UCLA professor of epidemiology Leeka Kheifets told Consumer Reports last year, that means Bluetooth devices may pose less of a danger than cell phones. But again, we don’t really know.
One potential cause for concern with Bluetooth, however: Many people wear Bluetooth headphones like Airpods for many hours on end. If the scientific community eventually concludes that there is a connection even between the lower-dose Bluetooth radiation and human illness, your ear—right up against your head—is the last place you’ll want to have put those devices.
And as the Medium post that re-started this conversation points out, some researchers suggest that signal power isn’t the only variable to think about when pondering health consequences of radiofrequency technology. Factors like the more inconsistent “pulses” of radiation emitted by wireless devices should also be taken into account, according to Martin Pall, a professor emeritus of biochemistry at Washington State University. But the science assessing how that relates to human health is just not there yet.
In any case, if you’re a fan of the precautionary principle, wired headphones would be the way to go.