Evidently the iPhone acts as a base station when it’s between any other users and a cell tower, even when it’s off, exposing users to high levels of radiation.
The good news is that, when the iPhone is is “FLIGHT MODE,” it does stop transmitting and receiving.
Dr. Mercola is an Medical Doctor and a certified physician. He is selling Blue Tube headsets, but I have used Tube Headsets from the very beginning and consider them a valuable accessory. They have a hollow blue tube so there’s no direct continuous wire from phone to head.
These sets are available all over the Internet, not just from Dr. Mercola. However, his do seem to be of high quality.