According to this guide "RADIATION PROTECTION STANDARD, Maximum Exposure Levels to Radiofrequency Fields — 3 kHz to 300 GHz":
"For frequencies between 100 kHz and 10 GHz, Seq, E² and H² must be averaged over any 6 minute period."
Assuming that a body cross-section of 1 square meter is exposed to a plane wave at 2.4GHz, the standard of exposure is 1W for professional exposure and 10W for consumer exposure (except in Russia, where it is only 0.01W). Apparently that means that you should not have a 100mW device in your pocket next to your skin in Russia, but 10mW is okay).
Anyway, most studies that talk about cancer concerns from RF exposure have to do with ELF (essentially power-line frequencies).
But people are free to believe whatever they choose in most countries, at least until mind-reading machines are perfected. Some people are willing to spend thousands of dollars on an E-Meter (a glorified ohm-meter) from the Church of Scientology.
Current state of the art mind-reading machines:
But this one is only for Scientologists:
And now that the neural code has been cracked, we will have direct neural interfaces where machines can inject sensory signals directly into our brains, including vision (to correct blindness). I can hardly wait, but some people will certainly not want electric fields injected directly into their bodies INTENTIONALLY. Oh well...
I have been waiting for my direct neural interface most of my life. Electromagnetic fields do not scare me (I have an amateur radio license, and I have designed antennas and transmitters and I understand RF radiation patterns).