Research posted on PubMed shows that cellphone radiation causes a localized increase in glucose metabolism in the brain. Some want to assume it's a thermal issue, but admitting that the cellphone is warming your brain is still cause for alarm. Besides that, microwave frequencies have the odd effect of causing atoms to rotate instead of just vibrate, which is something you learn about in Chem101, so despite being non-ionizing radiation, microwave frequencies still have an odd effect on atoms and molecules beyond other radio waves. Companies admitting that either of those might have any chance of increasing cancer risk would be financial suicide, so they'll pay to suppress anything suggesting such.
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