Single studies have alternately suggested cellphones are driving up cancer rates and that they pose no health threat at all. In 2011, the World Health Organization (WHO) declared that the devices are a “Class 2B carcinogen,” meaning they possibly can cause cancer in humans — but that’s also a distinction they share with pickles, aloe vera, and being a carpenter.
The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. The IARC has classified RF fields as “possibly carcinogenic to humans,” based on limited evidence of a possible increase in risk for brain tumors among cell phone users, and inadequate evidence for other types of cancer. (For more information on the IARC classification system, see Known and Probable Human Carcinogens.)
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).