In this frequency range, the interaction between matter and light is via the electric field component of light (totally different from how ionizing radiation messes you up). In particular, an oscillating electric field causes polar molecules to rotate or attempt to rotate, and the lag between the applied field and the response of the molecules manifests as dissipation—i.e. heating . This is the same dielectric heating which is the operating principle behind microwave ovens (which operate at 2450 MHz  similar to wifi). So if cell phones were to cause damage to tissue, the mechanism would be the same as what happens in a microwave oven—boiling the water in your head/body.
The program began, but Dr. Carlo soon discovered that everyone involved had underlying motives.“The industry wanted an insurance policy and to have the government come out and say everything was fine. The FDA, which looked bad because it didn’t require pre-market testing, could be seen as taking steps to remedy that. By ordering the study, law makers appeared to be doing something. Everyone had a chance to wear a white hat.”
We asked Dr. George Carlo his thoughts on EMF cases and shielding products, “most offer some protection, some of the time, to some people, because they can alter the immediate electromagnetic field environment around the person,” and immediately emphasizes the importance of “some,” which seems to tell us that it’s vastly unpredictable. “All waveforms in the environment are highly variable and they interact with other factors in the environment that make them even more variable.” This pretty much sums up that the artificial electromagnetic energy universe is vastly unpredictable.
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).