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.)

Jump up ^ Gandhi, Om P.; Morgan, L. Lloyd; de Salles, Alvaro Augusto; Han, Yueh-Ying; Herberman, Ronald B.; Davis, Devra Lee (14 October 2011). "Exposure Limits: The underestimation of absorbed cell phone radiation, especially in children". Electromagnetic Biology and Medicine. 31 (1): 34–51. doi:10.3109/15368378.2011.622827. ISSN 1536-8378. Retrieved 2015-04-25.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.