With more than 110 million cell phones in use in the United States, two congressmen Tuesday urged more study on the health effects of radiation from wireless phones after a government report showed research on the issue is inconclusive.

"When millions of Americans put this phone up next to their ear, even if only for brief periods of time, there are millions of them who wonder whether they may be hurting their own health or their children's health," said Rep. Edward Markey, D.-Massachusetts, at a news conference.

Markey and Sen. Joseph Lieberman, D.-Connecticut, in 1999 asked the General Accounting Office to research the issue amid growing concern over the effect of cell phone radiation on health.

The GAO report found "that research to date does not show radio frequency energy emitted from mobile phones to have adverse health effects, but there is not yet enough information to conclude that they pose no risk."

Based on that finding, Lieberman called for more research and education.

"Until we know more we've got to continue to pursue research, ensure effective regulation of cell phones, and most importantly inform the public as quickly and as clearly as possible about what we do know and what precautions are available so the public itself can make informed choices," he said.

More attention, Lieberman said, needs to be given to regulations requiring manufacturers to test the safety of their phones.

"The phones are tested for how much radiation is absorbed by the body to make sure they fall below the FCC standard," he said. "But the entire system rests on self-testing by manufacturers. But there are no standards for those tests. What I learned from the report is that slight differences in testing procedures can cause significant discrepancies in results."

Lieberman and Markey also urged the Food and Drug Administration and the Federal Communications Commission to jointly sponsor a Web site to provide consumers with the latest information on research into cell phone dangers and safety tips.

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