Are Cell
Phone Headsets Safe?
CNET Wireless
Journalist: David Carnoy
November 15, 2000
Until recently, the underlying safety of cell phone headsets was not really a cause for concern. The common wisdom was that if you were worried about cell phone radiation and its potential health hazards, the best way to talk safely was to get a headset. But that all changed a few months ago when Which, a British consumer magazine, published a study that suggested that headsets or hands-free kits actually increased the level of radiation inside the head by up to three times. Which further exacerbated the situation on November 2, when it printed a follow-up study confirming its previous findings.
As you might imagine, the study contains a lot of technical jargon that's not exactly layman-friendly. But emerging from the technobabble are some key issues that have fueled the controversy:
- ERA Technology, the independent laboratory that conducted the testing for Which, did not initially measure specific absorption rates (SAR). Instead, it set out to measure radio frequency (RF) radiation emissions. Which says it's not anti-SAR, but it questions the SAR measurement technique with regard to hands-free kits.
- After Which released its first study in April, the U.K. Department of Trade and Industry (DTI) commissioned its own SAR test on hands-free kits. According to the government's report, the kits reduced radiation exposure.
- In response to the DTI report, Which conducted some SAR tests at the same laboratory used by the DTI. According to Which, "We found no positions where the kits gave higher readings than the phones. But we also found that the shape of the SAR test rig made it impossible to get the hands-free kit wire into the position that gave the highest readings in ERA's tests."
So Are
They Safe?
Slightly baffled, I decided to call someone who'd actually tested headsets
in an independent lab to get his take on all this. I contacted Dr. Jacek J.
Wojcik, APREL Laboratories' CEO and president of the Spectrum Sciences
Institute. His company, based near Ottawa, Canada, recently measured SAR
levels for Plantronics' headsets and in the past has tested other headsets
and cell phones.
Decidedly in the SAR camp, Wojcik says ERA Technology is flat-out wrong. "That lab specializes in electromagnetics. There are electromagnetic fields everywhere, but the human body does not necessarily absorb the energy."
Wojcik is unmerciful in his criticism of ERA Technology's testing methods. "They don't understand what they're doing," he says. "They're defending mistakes they made in the first study and making more mistakes." He cites a litany of problems--from the way in which the testing room was set up to the amount of salt in the gel inside the phantom head that's meant to simulate the same electrical properties as human brain tissue. "I don't know what animal they picked up," he says, "but it wasn't human."
But let's get back to the real issue: Are headsets safe? Wojcik explains that SAR is created by radio frequency current. The current couples to the head via a magnetic field that has a limited radius around the power source (the phone). Move the power source away from your head, and your noggin won't be exposed to the magnetic field. While the headset cord or wire may carry a signal, it's not significant enough to create SAR at the level of the head. Contrary to Which's suggestion that labs fail to lay out the headset cord so that it's fully extended in a natural manner, Wojcik says his lab "lays out the cord in such a way that we can scan the whole cord."
Back to
the Numbers
Let's say for the sake of argument that those in the SAR community, who
represent the majority view, are right, while Which's study is flawed. That
still leaves us with the SAR data. Just what numbers do manufacturers have
for headsets?
Well, Nokia, Ericsson, and Motorola told me that all authorized headsets and hands-free kits for their phones have been tested in labs and that all have maximum SAR levels below the FCC's designated safe limit (1.6 W/kg). However, in keeping with their SAR nondisclosure policy, the companies declined to give me the SAR levels for those units.
Jabra, which makes the popular Jabra EarSet, couldn't provide me with actual rating numbers either. Instead, the company sent me a statement saying that "[Jabra] maintains that use of the Jabra EarSet reduces the level of RF power entering the head...by a factor of ten." That may be true, but it should be noted that the "factor of ten" Jabra cites for its EarSet was derived from internal test results, not an independent lab's.
Jabra's statement goes on to say, "Other major cell phone and headset manufacturers, such as Ericsson and Nokia, have gone on record to also confirm our position. These companies state clearly that their tests, as well as those by qualified outside test laboratories, confirm that the RF radiation at the head is reduced through the use of a headset."
As far as I know, Plantronics, which makes a wide assortment of headsets for cell phones and cordless phones, is one of the few companies to publicly release its SAR test results from an independent lab. APREL tested Plantronics' headsets and found that they reduced SAR levels to practically zero in the head.
Wojcik says that results of his tests of headsets from Plantronics and other major manufacturers show that those particular models have maximum SAR levels that are significantly lower than those of the phones with which they're tested. Unfortunately, he can't reveal what companies make the other headsets he's tested. Alas, the old disclosure policy rears its ugly head again.
Getting
Personal
"So based on your tests," I say to Wojcik, "if your wife were to ask you
whether headsets were safe, what would you tell her?"
"Nothing," he replies.
He cautions that his labs' findings don't mean we can declare headsets to be universally safe. It simply means that the models APREL has tested are well below the FCC's designated safe level. "You know, scientists have done tests on animals, and based on those tests, the FCC has set up very stringent limits, which we use as benchmarks. Can we say headsets are absolutely safe based on those numbers? No, because nothing's absolutely safe."
Wojcik doesn't use a headset himself; he's not comfortable with the feel. But he says he was happy to discover that the belt clip he wears for his StarTac does a good job keeping the phone away from his body. Yes, that's another side of the headset equation: where you carry your cell phone. For instance, if you have the phone in your pocket while talking with an earpiece, your leg will absorb the phone's RF emissions, but that's another column for another day.
However, Wojcik discourages people from using the unproven cell phone radiation shields that are becoming more and more prevalent in the marketplace. You don't want to attach anything to the phone that might diminish its performance, he explains, because that would actually cause the phone to work harder to receive a signal and potentially raise SAR levels, nor do you want a belt clip with any metal parts that might enhance the energy emitted from the phone.
But back to Wojcik's wife: Just what would he tell her about headsets?
"I think the psychological impact is important," he says. "I mean, people get headaches just from thinking they're being exposed to radiation. So I'd tell her that if you want to wear something that makes you feel safe, by all means do it."
The moral of this story, I suppose, is that perception is crucial in this whole debate of radiation levels. In many ways, the lack of public SAR information about headsets (and by public, I mean information printed on the outside packaging) was what made headset manufacturers vulnerable to these studies, which may or may not be flawed.