““Many experts, ...exposure at any level is unsafe, and they are correct.””
But there are rad sources that are natural. What we are not being told is these standards and where they rank compared to natural radiation sources. If the standards are at or below natural values they are B.S. in my book.
With these measurements there is a noise floor. The floor varies based on many factors. But standards that are below or near the floor can be rather meaningless and this is my suspicion with the fear mongers. To serve themselves and their agencies they have migrated the standards ever close to the noise floor and end up toggling with the floor values in many instances.
Not science any more, its bout the money and politics.