Are cell phones safe?

About 4 billion people use cell phones, but are they safe? Keep listening—scientists around the world are exploring this question right now. In the meantime, governments are suggesting that people try to limit exposure to radiation from the devices. “Better safe than sorry,” says Siegal Sadetzki, a physician in Israel who studies the health risks of cell phones.

Cell phone users can cut down on radiation exposure by only using the phone when the signal is strong. Another way to reduce exposure is to keep some distance between the phone and the ear.

The phones work by changing the sound of your voice into a radio wave, which it then sends out through an antenna. The phone uses the antenna to receive radio waves, which it then changes into sound waves that a user can hear. These radio waves are a form of radiation, which may be absorbed by tissues in a user’s head, if the phone is close enough.

Most of the scientists who are studying the health effects of cell phones are working in countries other than the United States, but that may change. The United States Senate has recently begun to investigate American research — which may affect 270 million users in the U.S.

Right now, evidence from scientific studies around the world is not strong enough to show a link between cell phone use and disease.

“The currently available scientific evidence about the effects of radiation emitted by mobile phones is contradictory,” says Dariusz Leszczynski, a scientist at Finland’s Radiation and Nuclear Safety Authority, in Helsinki. “There are both studies showing effects and some studies showing no effect.”

If scientists were able to show a link, then cell phones would be sold with a warning label. Scientists like Leszczynski, however, think it’s unwise to think of cell phones as 100 percent safe. Instead, he and his organization recommend that children not use cell phones because the radiation can reach further into their brains than it does into the heads of adults. They also recommend texting rather than talking—to keep the phone away from the head.

In France, the health ministry has been making similar suggestions to keep children off the cell phone. In Israeli, the government recommends that people use speakers or other hands-free devices to keep the phone away from the head. The Environmental Working Group, an advocacy organization in the United States, recommends that people buy low-radiation phones.

Some scientific studies do suggest a link between health problems and cell phone use. Last year, Sadetzki and her group found that heavy cell phone users had a 50 to 60 percent increased risk of a certain type of tumor. Sadetzi says that one reason studies may now be showing risk is that widespread use of cell phones didn’t begin until about 15 years ago. And it may take decades for disease to develop.

She says cell phones are here to stay, but “the question that needs to be answered is not whether we should use cell phones, but how.”