Mixed Message (Sidebar to "Do Cell Phones Need Warnings?"

By John Greenwald
Copyright 2000 Time
October 9, 2000

Can your cell phone really give you cancer? The best answer science can offer so far is maybe. Researchers have discovered that cell-phone radiation can cause subtle, short-term biological effects in humans--including changes in brain-wave patterns during sleep--but their full significance remains to be determined. Given that uncertainty and the fact that everyone from the National Cancer Institute to the World Health Organization is investigating cell-phone radiation, many experts caution that it is far too early to give the phones a clean bill of health.

Cell phones work by transmitting radio waves to base stations that plug calls into a network. The waves are a form of non-ionizing radiation--unlike, say, X rays, which have the power to change the atoms in human cells to potentially hazardous ions by scattering their electrons. Non-ionizing radiation can also be dangerous. At the high levels found in radar or inside microwave ovens, it can heat and severely damage tissue. The question for scientists is whether the low-energy (and low-heat) signals from cell phones can do harm. "What this debate is really about," says Microwave News editor Louis Slesin, "is whether cell phones have nonthermal health effects."

Cancer studies have been inconclusive since 1993, when a Florida man brought an unsuccessful lawsuit that blamed his wife's fatal brain tumor on her use of a cell phone. In a frequently cited 1997 report, Australian researchers exposed mice bred with a predisposition to lymphomas to two daily 30-min. doses of cell-phone radiation for up to 18 months. The mice developed tumors at twice the rate of animals that were radiation-free. But the results haven't been duplicated, and some scientists question their relevance.

The most outspoken cell-phone critic is George Carlo, whom the cellular industry hired to investigate the issue in the wake of the 1993 case. Backed by a $ 25 million grant, Carlo launched a series of studies that ended last year, including one that he claims shows a link between cell-phone use and a rare type of brain tumor. That report's principal author has said the correlation could be due to chance, but Carlo is undaunted. "No one study allows you to make a definitive determination about public health," he says. "It's how all the pieces fit together that counts." For now, the best advice science can offer about cell phones is handle with care. -- J.G.