The FCC sets the maximum amount of thermal radiation (heat) that cell phones are permitted to emit.  This limit is measured as the amount of radiation absorbed by a user and is known as the specific absorption rate (SAR). In 1996 the SAR for cell phone radiation was set at a maximum of 1.6 watts of energy absorbed per kilogram of body weight. Manufactures of cell phones must test their products to ensure that they meet this standard. Random tests of phones on the market by FCC scientists further ensure that radiation levels meet FCC guidelines. 
Result: More than 100 studies on 2.45 GHz radiation were analyzed, most of which found changes compared to the control groups at levels below the safety guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (issued as exposure limits of the 26th Federal Pollution Control Ordinance (BImSchV) in Germany). The available studies document damage to the reproductive system, impacts on the EEG and brain functions, as well as effects on the heart, liver, thyroid, gene expression, cell cycle, cell membranes, bacteria, and plants. As a mechanism of action, many studies identify oxidative stress. Adverse effects on learning, memory, attention, and behavior are the result of cytotoxic effects.
MATERIAL AND METHODS: 70 male Wistar rats weighing 200-250 g were randomly divided into 7 groups (10 rats in each group).The first stage one-day test: Group A (received vitamin C 250 mg/kg/day orally together with 8- hour/day Wi-Fi exposure). Group B (exposed to Wi-Fi radiation). Group C (received vitamin C). Group D or Control (was neither exposed to radiation of Wi-Fi modem nor did receive vitamin C). The second phase of experiment had done for five consecutive days. It involved Group E (received vitamin C), Group F (exposed to Wi-Fi radiation), Group G (received vitamin C together with Wi-Fi radiation). The distance between animals' restrainers was 20 cm away from the router antenna. Finally, blood samples were collected and assayed the level of hepatic enzymes including alkaline phosphatase (ALP), alanine amino transferase (ALT) aspartate amino transferase (ASL), gamma glutamyl transferase (GGT) and the concentration of Blood Glucose, Cholesterol, Triglyceride (TG), High density lipoprotein (HDL) and low density lipoprotein (LDL).
Nevertheless, a group of scientists got together in the mid-2000s, calling themselves the BioInitiative Working Group. This group, which largely consisted of wireless radiation researchers, has written a harsh reply as feedback to the reports claiming that posed no health risks. The reply lists a wide range of health effects scientists at the European Commission have unfortunately either ignored or dismissed.