How Safe Is Your Cell Phone?

It takes a little extra work to get in touch with Andrea Boland. The Maine state representative answers e-mails and lists her business and home phone numbers on the Web. But unlike many politicians surgically attached to their BlackBerrys, she keeps her cell switched off unless she's expecting a call. And if she has her way, everyone in Maine — and perhaps, eventually, the rest of the U.S. — will similarly think twice before jabbering away on their mobiles.

In March, Maine's legislature will begin debating a bill she submitted that would require manufacturers to put a warning label on every cell phone sold in the state declaring, "This device emits electromagnetic radiation, exposure to which may cause brain cancer." Her warning would continue, "Users, especially children and pregnant women, should keep this device away from the head and body." (See a report card on cell phones' radiation.)

For those of you now eyeing your cell phones suspiciously, it's worth noting that both the National Cancer Institute and the World Health Organization say there isn't evidence to support the assertion that cell phones are a public-health threat. But a number of scientists are worried that there has been a dangerous rush to declare cell phones safe, using studies they feel are inadequate and too often weighted toward the wireless industry's interests. An analysis published by University of Washington neurologist Henry Lai determined that far more independent studies than industry-funded studies have found at least some type of biological effect from cell-phone exposure. (See pictures of the cell phone's history.)

Several countries — including Finland, Israel and France — have issued guidelines for cell-phone use. And San Francisco Mayor Gavin Newsom, who began researching the issue when his wife was expecting their first child, is hoping his city will adopt legislation that would have manufacturers print radiation information on cell-phone packaging and manuals and require retailers to display the data on the sales floor.

With 270 million Americans and 4 billion people around the world using cell phones — and more signing up every day — a strong link between mobiles and cancer could have major public-health implications. As cell phones make and take calls, they emit low-level radio-frequency (RF) radiation. Stronger than FM radio signals, these RF waves are still a billionth the intensity of known carcinogenic radiation like X-rays. (See pictures from an X-ray studio.)

The wireless industry contends that RF radiation lacks the strength to alter molecules in the human body; the Federal Communications Commission (FCC) maximum for cell-phone-signal exposure is intended to prevent RF radiation from heating tissue to the point that cells are damaged. Cell-phone RF radiation's "effect on the body, at least at this time, appears to be insufficient to produce genetic damage typically associated with developing cancer," Dr. Robert Hoover, director of the National Cancer Institute's Epidemiology and Biostatistics Program, testified at a 2008 congressional hearing.

But the body of research is far from conclusive. In 1995, Lai co-wrote a study showing that a single two-hour exposure of RF radiation — at levels considered safe by U.S. standards — produced the sort of genetic damage in rats' brain cells that can lead to cancer. Though subsequent researchers — often funded in part by the wireless industry — failed to replicate Lai's results, a 2004 European Union — funded study reported similar findings.