Radiation emitted from mobile phones may increase the risk of brain cancer, the World Health Organization said Tuesday after a review of available scientific evidence.
A panel of the WHO's International Agency for Research on Cancer said cellphones present the same cancer risk as some forms of pesticides.
The panel, composed of 31 scientists from 14 countries, had been reviewing the scientific literature since May 24 in Lyon, France.
Members noted that radiation exposure from handsets has a greater impact on humans than that emitted from cellular towers. They also suggested a rare brain tumor known as a glioma could be a possible consequence of mobile phone usage, and to a lesser extent, an equally rare inner ear tumor called an acoustic neuroma.
Representatives for manufacturers scoffed at the findings, saying the data were based on flimsy evidence.
John Walls, a vice president at the trade group CTIA-The Wireless Association, said mobile phone users should not be alarmed. WHO's cancer research agency "conducts numerous reviews and in the past has given the same score to, for example, pickled vegetables and coffee."
Panel chairman Dr. Jonathan Samet of the University of Southern California said, "The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cellphones and cancer risk."
In February, a collaborative study between Brookhaven National Laboratory and the National Institutes of Health that did not investigate a cancer risk discovered the phones increase brain sugar metabolism.
Dardo Tomasi, a visiting Brookhaven scientist who participated in the research, said he was surprised by the WHO's finding.
"That's a big statement," Tomasi said Tuesday.
Dr. Norman Kleiman, a faculty member of Columbia University's Mailman School of Public Health and an expert in how radiation causes DNA damage, said cellphones do not emit the kind of energy widely known to damage genes. The devices emit radio-frequency radiation, similar to the energy of microwave ovens.
"From a scientific viewpoint, there is no plausible explanation why this kind of radiation would cause cancer. This is not ionizing radiation," Kleiman added, referring to the kind associated with X-rays.
Dr. Michael Schulder, director of the North Shore-Long Island Jewish Brain Tumor Institute and vice chairman of Neurosurgery at North Shore University Hospital in Manhasset, said the findings are not frightening.
"They rated it a 2-B risk," Schulder said. "That just says there's a possibility of a connection and that it bears further observation. It's hardly a statement of major concern."