Cell phone radiation might cause cancer, according to the World Health Organization, which until Tuesday has said that there were no known health risks associated with cell phone use. The WHO’s International Agency for Research on Cancer has now tied mobile phone radiation to an increased risk for glioma brain tumors.
The judgment doesn’t stem from new research. Instead, a panel of 31 scientists from 14 countries, including the United States, spent a week poring over existing studies.
They added radiofrequency electromagnetic fields to a long list of “possibly carcinogenic” agents; other such agents are coconut oil, DDT, gasoline exhaust, lead, talcum powder, titanium dioxide, and some types of HIV and HPV viruses.
The CTIA wireless industry trade group quickly responded, stating that the classification “does not mean cell phones cause cancer.” The FCC and FDA also maintain that there’s no evidence for blaming cancer on cell phones.
However, most scientists agree that there is as yet no final verdict on whether mobile phones threaten health. Because cell phone radiation isn’t ionizing–unlike radiation from nuclear fallout or X-rays, for example–conventional wisdom has held that the only way it harms tissue is when a device overheats. At the same time, few experts say with certainty that using a two-way microwave radio close to your body is absolutely safe, either. After all, humans at the core are electromagnetic creatures, so why wouldn’t electromagnetic radiation affect us?
The WHO panel looked at research including the results of the decade-long Interphone study, which generally failed to connect brain tumors with cell phone usage. However, the panel noted that evidence tied 30 minutes or more of talking on a mobile phone each day to a 40 percent rise in glioma tumors over 10 years. A February study in the Journal of the American Medical Association found that cell phone radiation changed brain chemistry by raising glucose levels.
Watchdog groups accuse the wireless industry of essentially turning the world’s 5 billion users into guinea pigs. Among the critics is Devra Davis, an epidemiologist who founded the Environmental Health Trust and wrote the book “Disconnect: The Truth About Cell Phone Radiation.” 
It is hardly reassuring to the public that, in protesting San Francisco’s move to require cell phone radiation labels, the CTIA moved its annual conference to Florida this year.
Given the current state of the available evidence, though, the easiest way for a person to turn a mobile phone into a killing machine is to pay more attention to it than to the road while driving.
Nevertheless, if you prefer to exercise caution, these common-sense tips to reduce your radiation exposure won’t harm your productivity or make you look like a hypochondriac.
1. Use a Headset
You’ll get far less radiation exposure from a headset than from a phone pressed to your ear. Check out some Bluetooth headsets that fared well in PCWorld’s tests. Another option is to use your speakerphone (behind closed doors, please). If that’s not possible, follow the manual. Apple, for instance, suggests holding an iPhone 0.625 inch away from your head.
2. Keep the Phone at Arm’s Length
Would-be parents might be wise to keep smartphones out of pockets or belt holsters, since reputable studies of men who use cell phones link frequent usage with a decrease in sperm count and quality. For obvious reasons, there haven’t been lab tests exploring how cell phone radiation may affect developing fetuses. But if you’re pregnant, you’re already avoiding tuna and soft cheese, so why risk holding a phone close to your belly?
3. Text, Don’t Talk
Text messaging involves less radiation than does making a phone call. (Just don’t text while walking, since bumping your head will hurt you much more quickly than any wireless radiation might.)
4. Turn It Off
Even if you check your work e-mail at midnight, there’s little need to keep your phone turned on 24/7. (The science may be fuzzy on mobile phone radiation, but stress and sleep deprivation clearly harm your health.) Instead of keeping your handset by your pillow for a wake-up call, use a dedicated alarm clock.
5. Keep That Charger Handy
6. Look for Phones With Low SAR Levels
I have mixed feelings about offering this advice. Specific Absorption Rate (SAR) levels are supposed to indicate how much radiofrequency energy a body absorbs from a device. Yet these labels are not like calorie counts on a TV dinner. The level isn’t necessarily what you get when chatting, texting, or playing an app on a given phone. Each of those activities involves constantly varying levels of power and signal strength. The FCC explains more about what SAR levels mean. That said, CNet frequently updates its list of the highest- and lowest-radiation phones.
6. Keep Cell Phones Out of the Hands of Children
If non-ionizing radiation affects adult brains in ways we still don’t fully understand, it’s likely to affect children even more because their skulls and brains are still developing. The key recommendation here: Don’t treat a cell phone as a toy. If you’re letting your toddler play with it anyway, at least turn it off or shut off the signal.
7. Don’t Believe the Hype About Radiation-blocking Products
Countless ads hawk devices meant to protect your body from electromagnetic frequencies (EMF). However, there’s no conclusive evidence that an EMF medallion or sticker will work as advertised or even work at all. In fact, some of these products can force a phone to do more work and emit more radiation to compensate for a blocked signal.