On an energy-frequency scale, cell phone RF waves fall somewhere between microwave ovens and television signals. But any radiation-emitting device used by millions raises health questions that can take years to settle. Microwaves damage tissue by burning it. Cell phones' lower-powered RF waves are not thought to cause enough heat to hurt. Frequent callers who feel heat are actually feeling the phone's battery.
Companies say if they comply with that standard, their phones are safe.
But, yielding to increasing public concern, major wireless companies plan to disclose each a phone's SAR with models now beginning to hit store shelves. Phone packages will bear an ID number enabling consumers to look up radiation absorption levels on the FCC's Web site before buying. Or after they buy the phone, they can find the SAR and an explanation of what it means inside the package. To determine SARs, cell phones undergo rigorous testing using equipment like Chan's in the FCC's concrete-block laboratory in this Washington suburb. A large hollow model of the head holds a solution, made mostly of water and sugar, that mimics the electrical properties of brain and other tissue.