Specifically, we looked for studies that measured rates of acoustic neuromas, gliomas, meningiomas, and thyroid cancers. We also narrowed our search to studies that looked at the effect of radio-frequency radiation originating from an actual cellphone, rather than experimental equipment. We did this because we wanted evidence that could apply to real life, not specific laboratory settings or hypothetical outcomes.

The U.S. government doesn’t seem very troubled, either. The Food and Drug Administration says on its website that research generally doesn’t link cell phones to any health problem. And although the Federal Communications Commission requires manufacturers to include information in user manuals about cell-phone handling, that’s often buried deep in the fine print.
There’s a broad range of radiation types, and lots of harmless things emit radiation — like bananas, Brazil nuts, and granite countertops, according to Cincinnati Children’s Hospital. The type of radiation that comes out of our cellphones isn’t the same radiation that’s released by nuclear fallout or X-rays. Cellphone radiation, also known as radiofrequency radiation, is much weaker — so it can’t cause the same kind of cell damage that can lead to cancer.
The next scientific step will be to determine what this means for humans. The peer-reviewed papers will be passed on to the US Food and Drug Administration, which is responsible for determining human risk and issuing any guidelines to the public, and the Federal Communications Commission, which develops safety standards for cell phones. The FDA was part of the group of federal agencies who commissioned the studies back in the early 2000s.

The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.