A Health Warning for a Wireless Age

Cigarette packs in the U.S. have carried government health warnings since 1965. Last month, San Francisco's city government brought such warnings into the Information Age, voting 10-1 to require that stores post the level of radio waves emitted by each mobile phone they sell. In passing the law, called the Cell Phone Right-to-Know Ordinance, San Francisco entered a battlefield of dueling scientists and conflicting findings.

A cell phone's main source of radio frequency, or RF, energy is produced through the antenna. The closer the antenna is to the head, the higher the exposure, according to the National Cancer Institute. But there's no scientific consensus on whether exposure from frequent cell-phone use can lead to cancer, as many fear. The latest study on the issue, published last month by the World Health Organization, couldn't find a conclusive link. Researchers did, however, report a "suggestion," backed up by incomplete data, that the heaviest phone use may be tied to gliomas, the most common type of brain tumor and the one that claimed the life of Senator Edward Kennedy last year. A more worrying 2005 study from Sweden claimed to find an apparent link between brain cancers and mobile-phone use.

The researchers behind both studies caution that it can take decades of exposure to a cancer-causing agent for a tumor to appear. Because heavy cell-phone use is a relatively new phenomenon, they need more time and data to study the issue. Additionally, Mary McBride, a scientist at the British Columbia Cancer Agency and a co-author of the WHO report, says that most studies, including hers, have excluded children, whose brains absorb more energy than adults and whose phone use has grown exponentially.

The Federal Communications Commission currently regulates cell-phone emissions based on the amount of RF energy absorbed by the body during phone use, a metric called the "specific absorption rate." The maximum SAR allowed under a 20-year-old standard is 1.6 watts per kilogram of body weight, and any emission level below that is considered safe, at least by the FCC. The San Francisco ordinance will require sellers to post the SAR regardless of the rate. That may confuse consumers, says John Walls, a Washington (D.C.) spokesman for trade group CTIA-The Wireless Assn., since they're likely to infer that a higher SAR rating means a more dangerous phone. "As long as those devices meet or fall below the FCC standard, they are all considered safe—period," he says.

Many consumers and activists argue that transparency can't hurt. "It totally makes sense to give consumers more information," says Renée Sharp, an Oakland (Calif.) scientist with the Environmental Working Group, which supports the measure. "We are not saying we know cell phones cause cancer."

Ellie Marks, of nearby Lafayette, Calif., was also pleased by San Francisco's decision. Her husband, Alan, has a brain tumor she believes was caused by his frequent use of mobile phones. An early adopter, he got his first phone in 1987, she says, and for two decades he used it more than 500 hours a year, mostly glued to his right ear. In May 2008, he was diagnosed with a glioma in his right frontal lobe.

Since then Marks has advocated for educating customers about what she calls the avoidable risks of mobile phones, testifying before Congress as well as the California and Maine state legislatures. In each case, measures to provide information on RF emissions were defeated. Now that she's tasted victory in San Francisco, though, she says she'll keep pushing. Next up: Burlingame, Calif., where Councilman Michael Brownrigg plans to introduce a bill modeled on the one passed by his neighbors to the north. Marks may soon find herself back before Congress, too. On June 30, Dennis Kucinich, the Democratic congressman from Cleveland and two-time Presidential candidate, announced he'll introduce a federal right-to-know bill similar to San Francisco's.

Industry representatives, meanwhile, are expressing their displeasure with their wallets. After October, the CTIA says, its annual trade show will no longer grace the City by the Bay. "We thought the Board of Supervisors' decision sent a very clear message," Walls says. "We weren't wanted in San Francisco."

The bottom line: Despite a lack of definitive evidence tying cell phones to cancer, San Francisco wants consumers to know the emission levels of handsets.

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