The American Cancer Society (ACS) states that the IARC classification means that there could be some risk associated with cancer, but the evidence is not strong enough to be considered causal and needs to be investigated further. Individuals who are concerned about radiofrequency exposure can limit their exposure, including using an ear piece and limiting cell phone use, particularly among children. (5)

Wherever you come out on the cellphone and cancer question, one thing is clear: How we live with cellphones, along with our exposure to the radiation they emit, has changed dramatically over the past several decades. That has policy implications; it’s something regulators, researchers, and cellphone companies need to pay attention to. In that context, a few things should happen:

Pong’s claims for its case have stood up to the scrutiny of Wired magazine and the Better Business Bureau (Advertising Self-Regulation Council 2012; Ganapati 2009). In tests conducted by Cetecom, a cell phone radiation certification lab, and observed by a reporter from Wired magazine, an iPhone 3G tested without a case had a maximum SAR of 1.18 W/kg when held at the ear. The same phone tested with a Pong case had a maximum SAR of 0.42 W/kg (Ganapati 2009).  
It’s true that cellphones do emit radiation. And radiation is a scary word for a lot of people, thanks in part to the horrific aftermath of nuclear accidents and photographs of victims of the nuclear bombs the US dropped on Japan in World War II. People hear radiation and they associate it with nuclear radiation and the bomb, says Geoffrey Kabat, a cancer epidemiologist at the Albert Einstein College of Medicine and author of the book Getting Risk Right. “There are all these associations and those are deeply ingrained in people. But it doesn’t apply here.”

Since 2001, the FCC has allowed manufacturers to test phones at a distance of up to one inch from the body to account for the use of a holster. In a 2012 report, however, the Government Accountability Office, the Congressional watchdog agency, noted that many cell phone owners actually keep and use their phones right next to the body, so these outdated testing policies could result in radiofrequency (RF) radiation exposure greater than the FCC’s legal limit (GAO 2012). The GAO report concluded:
The World Health Organisation (WHO) released a fact sheet about these issues, shortly after the IARC re-classification, entitled "Electromagnetic fields and public health: mobile phones". The fact sheet points to the findings of the IARC and describes some of the known short-term and long-term effects of phone use, but ultimately, it lands on the side of where the most conclusive evidence exists:
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).