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Nice quality vinyl bumper sticker is a not-so-gentle reminder to fellow motorists of the one of the many dangers of cellphone use: distraction! If you ever get the chance, you can also explain the other hazards as well: reaction time, increased permeability of the blood-brain barrier, and possibly brain tumors. Good for cars, trucks, bikes, skates and just about any other moving vehicle.
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.

In the studies, the researchers looked at a whole slew of health outcomes (like offspring survival, bodyweight changes, and body temperature changes), but importantly, they also looked at brain tumors, including gliomas. They exposed the animals to radio frequency radiation for up to nine hours a day over two years, and then examined more than 40 tissues in each animal. And they had a control group that wasn’t exposed to radiation for comparison.
The Working Group indicated that, although the human studies were susceptible to bias, the findings could not be dismissed as reflecting bias alone, and that a causal interpretation could not be excluded. The Working Group noted that any interpretation of the evidence should also consider that the observed associations could reflect chance, bias, or confounding rather than an underlying causal effect. In addition, the Working Group stated that the investigation of risk of cancer of the brain associated with cell phone use poses complex methodologic challenges in the conduct of the research and in the analysis and interpretation of findings.
Because of inconsistent findings from epidemiologic studies in humans and the lack of clear data from previous experimental studies in animals, in 1999 the Food and Drug Administration nominated radiofrequency radiation exposure associated with cell phone exposures for study in animal models by the U.S. National Toxicology Program (NTP), an interagency program that coordinates toxicology research and testing across the U.S. Department of Health and Human Services and is headquartered at the National Institute of Environmental Health Sciences, part of NIH.
None of the three cases contain metallic parts, which are known to affect SAR, but all increased the user’s radiation exposure. The effect on radiation exposure would likely vary with each of the hundreds of cases on the market, and each would have to be tested individually to come up with an exact measure. The results in Table 1, however, are believed to reflect the range of radiation increases.
SAR LEVELS ARE very deceptive when it comes to health hazards!  The Pong case is taking advantage of the fact that current safety regulatory guidelines provide no non-thermal assurances of safety what so ever! Other-words Pong is using inadequate safety standards to prove the legitimacy of the Pong cell phone case – Citing official documents being reviewed by the FCC’s “Reassessment of Federal Communications Commission Radio-frequency Exposure Limits and Policies” (Proceeding Number 13-84), as it turns out, the level SAR rating of your phone is almost irrelevant, as it doesn’t consider health effects from non-thermal levels of radiation exposure at all.
The first one is easy, cellular frequencies vary between 450–2000MHz, but 800 or 900 MHz is the most common. The power emitted by a cell phone varies over the course of the call (higher when making initial contact, which lasts a few seconds). It can go up to 2 Watts at the start of a call, and can go down to .02 Watts during optimal operation [2]. Of course, most people barely use cell phones for calls, but I am using this example as a worst case scenario, because the phone is not right by your head when you are browsing Tinder.

A study by the Corporate EME Research Laboratory and Motorola Florida Research Laboratories tested 9 different cell phone radiation shields, 5 of which claimed to block 99% of cell phone radiation. The other 4 shields tested claimed to emit a reverse radiation that would cancel out the harmful radiation from cell phones. The study found that all of the radiation shields had no effect on the amount of radiofrequency radiation a cell phone user is exposed to from their phone.[2]

With the background levels of information-carrying radio waves dramatically increasing because of the widespread use of cell phones,Wi-Fi, and other wireless communication, the effects from the near and far-fields are very similar. Overall, says Dr. Carlo, almost all of the acute and chronic symptoms seen in electrosensitive patients can be explained in some part by disrupted intercellular communication. These symptoms of electrosensitivity include inability to sleep, general malaise, and headaches. Could this explain the increase in recent years of conditions such as attention-deficit hyperactivity disorder (ADHD), autism, and anxiety disorder?
It'd be wrong to say that there is no evidence of harm at all. In fact, the re-classification by the IARC came about in the first place because the Working Group contributing to the Interphone study acknowledged "limited evidence" of an increase in glioma (a type of tumour, commonly found in the brain) among phone users in one of the studies. In this study, which concluded in 2004, researchers found that participating phone owners who had used their handsets for calls for more than 30-minutes a day, over a period of ten years, had an increase incidence of glioma.

In theory, men may be more vulnerable to cellphone radiation’s effects on fertility than women. Sperm cells are made and stored in testicles, whereas egg cells are stored in ovaries. And the location of these two organs means that sperm and eggs have different levels of protection from radiation. Testicles sit outside of the abdomen, which makes them more sensitive to radiation. And, well, a phone often sits in your front pocket.
Transmitters, including cell phones, emit radio signals on more than the assigned frequency. These other signals on other frequencies are “harmonics” and/or “noise” and/or “dirty” signals from less than optimal transmitters, antennae, and/or resonating frequencies emitted from metallic objects in close proximity to the transmitter, like the other components of the cell phone.

DefenderShield Cellphone Radiation Case also claims independent testing and says in their website: That a "sophisticated layering of separate non-toxic, human safe materials processed for maximum radiation blocking efficiency. Each material has unique and targeted radiation-shielding characteristics designed to work in unison to eliminate all radiation emissions from 0 to 10 GHZ and Defender Shield technology refracts, conducts and finally absorbs all these potentially harmful emissions."  In this demonstration, the radiation level measured when DefendeShield case was on is still quite a bit above the level of exposure that I would recommend. I personally do not recommend-holding a phone with a shielding case to your head as the DefenderShield website shows a young woman doing as she demonstrates the product. 
As our video points out: Measurements will vary with signal strength and other factors and that includes ambient energy. I talk about ambient energy in a lot of my videos-it's the energy that's in whatever environment I happen to be measuring in that's coming from a source of wireless energy that isn't the subject of what I'm measuring.  My home is not a lab of course, but fortunately it's always measured very low for RF radiation. 
The tricky part about measuring the radiation from a cell phone is that the emission strength varies widely over time. There will be strong bursts of varying intensity, followed by quiet periods. This makes it hard to compare "apples to apples". Also, because you are measuring up close to the source, you must use a near field meter AND you must maintain the position of the meter very precisely.

California officials issued the new report in response to increasing smartphone use in the United States, especially among children. About 95% of Americans own a cell phone, according to a press release from the California Department of Public Health, and the average age for a first cell phone is now 10 years old. About 12% of people use their smartphones for daily Internet access.
SafeSleeve Anti Radiation Case: Safe Sleeve website says they integrate FCC accredited independent lab tested "shielding technology" in their products. There are many links to "SafeSleeve, Is it a Scam?" and "Does SafeSleeve work?" online, but if you follow those links you'll find they go to the actual SafeSleeve site where the question of SafeSleeve protection is addressed.  You'll see in this demonstration that the radiation level was higher with the SafeSleeve Case on.
But the pair of studies by the US National Toxicology Program found “clear evidence” that exposure to radiation caused heart tumors in male rats, and found “some evidence” that it caused tumors in the brains of male rats. (Both are positive results; the NTP uses the labels “clear evidence,” “some evidence,” “equivocal evidence” and “no evidence” when making conclusions.)
We also spoke to experts and searched government reports to try to find any other high-quality evidence that may not have been published in an academic database. We included the National Toxicology Program’s animal studies, since they are considered some of the most important animal research that was funded by the government to help answer the question of whether cellphones cause cancer. We also included research on the fertility effects of cellphone radiation, since that was a concern many researchers in the field had.
Though some findings were reassuring, others do raise concerns. Specifically, three of the studies—one from Sweden, another from France, and a third that combined data from 13 countries—suggest a connection between heavy cell-phone use and gliomas, tumors that are usually cancerous and often deadly. One of those studies also hinted at a link between cell phones and acoustic neuromas (noncancerous tumors), and two studies hinted at meningiomas, a relatively common but usually not deadly brain tumor.
An analysis of an "eagerly anticipated" study using rats and mice by the National Toxicology Program indicates that due such issues as the inconsistent appearances of "signals for harm" within and across species and the increased chances of false positives due to the multiplicity of tests, the positive results seen are more likely due to random chance. The full results of the study were released in February 2018.[10]
Again, non-ionizing radiation — the radiation from cellphones — doesn’t have enough energy to break our DNA, and therefore, we have traditionally thought, it couldn’t cause cancer. But there is some question about whether it’s as harmless as was once believed, or whether there might be another mechanism at play, other than direct DNA damage, that could lead to cancer or other biological problems.
An analysis of data from NCI's Surveillance, Epidemiology, and End Results (SEER) Program evaluated trends in cancer incidence in the United States. This analysis found no increase in the incidence of brain or other central nervous system cancers between 1992 and 2006, despite the dramatic increase in cell phone use in this country during that time (22).