A federal agency, the National Toxicology Program has released the results of the largest experiments to date and it has found evidence that radio waves from some type of cellphones could raise the risk of development of brain cancer. The study was performed on rats but some researchers point out that the implications are significant as billions of people are using cell phones. findings of the study — 384 pages devoted to rats, 260 to mice — had been conveyed to the Federal Communications Commission and the Food and Drug Administration, which regulate cellphones and gauge any risks to human health. Dr. Bucher declined repeatedly to assess the hazard. “We believe that the link between radio-frequency radiation and tumors in male rats is real,” John Bucher, a senior scientist at the National Toxicology Program, said in a statement.
Rats in the studies were exposed to radiation nine hours a day for two years — far longer even than heavy users of cell phones. The exposures started before birth and continued until they were about 2 years old. 2 to 3 percent of the male rats exposed to the radiation developed malignant gliomas, a deadly brain cancer, compared to none in a control group that received no radiation. Many epidemiologists see no overall rise in the incidence of gliomas in the human population. The study also found that about 5 to 7 percent of the male rats exposed to the highest level of radiation developed certain heart tumors, called malignant schwannomas, compared to none in the control group. Malignant schwannomas are similar to acoustic neuromas, benign tumors that can develop in people, in the nerve that connects the ear to the brain. The rats were exposed to radiation at a frequency of 900 megahertz — typical of the second generation of cellphones that prevailed in the 1990s, when the study was first conceived.
Current cellphones represent a fourth generation, known as 4G, and 5G phones are expected to debut around 2020. They employ much higher frequencies, and these radio waves are far less successful at penetrating the bodies of humans and rats. See the article in the New York Times on the study https://www.nytimes.com/2018/11/01/health/cellphone-radiation-cancer.html .