Another way to think about the situation is to consider the steady state power emission of .02 Watts and ask how long it would take to heat up your body by one degree Celsius if your entire volume was exposed. Take your body mass to be 100 kg and approximate it as being composed entirely of entirely of water. If all of the radiation was absorbed and went into heating you up (which it isn’t), it would take 20900000 seconds (specific heat*mass*1 degree/power) or 241 days to heat you up by one degree. Fortunately, you have metabolic processes in your body, or possibly air conditioning, to mitigate this heating.
Unfortunately, however, we’ll probably never have an RCT on cellphones and cancer in humans. It’d be too difficult and too expensive to randomly assign particular levels of cellphone use to thousands of people and have them stick with those plans for enough time (we’re talking at least five years) to figure out whether certain types of phones or phone use patterns cause cancer to develop. That’s not to mention the fact it’d be nearly impossible to find a group of people willing to not use cellphones and then make sure they actually stick to their promise.

Let’s be honest, we’re addicted to our smartphones. According to an ABC news report, the average person checks their phone 150 times per day, not to mention the other 15 hours per day it sits in your pocket. It’s also nothing new that cell phones emit Electromagnetic Fields/Radiation (EMF/EMR) when it’s glued to the side of our head more than 22 times per day. 

It also means regulators need to make sure their policies reflect new levels of exposure. The Federal Communications Commission currently oversees cellphone safety and sets the limits for how much radiation people should be exposed to. (This is measured by the specific absorption rate — the rate at which the body absorbs radio frequency energy — and the current limit for cellphones is 1.6 watts of energy per kilogram of tissue. The whole-body threshold is a SAR value of 0.08 watts per kilogram, and the tower radiation limit is 10 watts per square meter.)

That mystery probably stokes fears about cellphone radiation instead of soothing them, though — in part because of how we in the media cover the rare and frightening. We’ve seen the same thing with fear over nuclear power plants, according to a paper published in Science in the 1980s by psychologist Paul Slovic. “Because nuclear risks are perceived as unknown and potentially catastrophic, even small accidents will be highly publicized and may produce large ripple effects,” Slovic wrote.
The papers found that, in male rats, there was “clear evidence” that exposure to cell phone radiation increased risk for a rare type of malignant tumor called schwannoma in the connective tissues that surround nerves in the heart (they found “equivocal” evidence for the same thing in female rats). They also found “some evidence” that the radiation caused malignant glioma—a type of brain cancer affecting glial cells—in the male rats.
The Ministry of Health Medical Administration circular (from 2002) addressed to hospital Directors, states that use of mobile phones and wireless handheld transceivers (walkie talkie) in the hospital, must on the one hand guarantee the patient’s wellbeing and safety, and on the other hand, allow the staff, the patients and their families to enjoy the service benefits. This circular outlines the areas where use of mobile phones is strictly forbidden and areas where use is permitted (while keeping an appropriate safety distance from areas where life-supporting equipment or systems are operated).
As a result, stories about a single nuclear meltdown or possible link between cellphone radiation and cancer will be amplified much more than news about the nine people who probably died today in the US from distracted driving. “This possible health effect from radiation is pretty esoteric at this point. If there is anything there, it seems to me like it’s going to be very, very small,” says Kenneth R. Foster, a bioengineering professor at the University of Pennsylvania who has been investigating whether there are biological effects from radio waves since the 1970s. “Driving and texting, people get killed doing that — but it’s not a very exciting risk to worry about.”

A phone's specific absorption rate (SAR) reveals the maximum amount of radiation the human body absorbs from the phone while it's transmitting. SAR testing ensures that the devices sold in the U.S. comply with the Federal Communications Commission (FCC) SAR exposure limit, but the single, worst-case value obtained from this SAR testing is not necessarily representative of the absorption during actual use, and therefore it is not recommended for comparisons among phones. In short, selecting a lower SAR phone will not reliably ensure lower radiation absorption during use. The FCC has more information at Specific Absorption Rate (SAR) For Cell Phones: What It Means For You.
Dr Davis holds a B.S. in physiological psychology and an M.A. in sociology from the University of Pittsburgh, 1967. She completed a PhD in science studies at the University of Chicago as a Danforth Foundation Graduate Fellow, 1972 and a M.P.H. in epidemiology at the Johns Hopkins University as a Senior National Cancer Institute Post-­Doctoral Fellow, 1982. She has authored more than 200 publications and has been published in Lancet and Journal of the American Medical Association as well as the Scientific American and the New York Times.
The frequency of radiofrequency electromagnetic radiation ranges from 30 kilohertz (30 kHz, or 30,000 Hz) to 300 gigahertz (300 GHz, or 300 billion Hz). Electromagnetic fields in the radiofrequency range are used for telecommunications applications, including cell phones, televisions, and radio transmissions. The human body absorbs energy from devices that emit radiofrequency electromagnetic radiation. The dose of the absorbed energy is estimated using a measure called the specific absorption rate (SAR), which is expressed in watts per kilogram of body weight.