br Occasionally, certain areas read HIGH in the radiomicrowave setting. These include door seals around microwave ovens, and cellular phones (but not regular radio phones, which are very low-power). Radiomicrowaves can be shielded in the same way as electric fields, although the lower frequency radio waves are not shielded by your hand as easily as microwaves are. (Metal screens will shield both.) In the United States, radars and FM transmitters can legally expose residents to moderately high power levels (as high as 10 mWcm2 briefly or .57 mWcm2 near cellular towers), but such exposure is not common.