7.3 Controllability of natural sources From the viewpoint of radiation effects, a concept that natural radiation exposure is the same as artificial one is understandable, but from the viewpoint of radiation protection or control, the concept is not appropriate, because natural radioactive sources has already widely existed since the birth of the earth. While it is natural that human being has a heavy responsibility to control artificial radiation exposure accompanied with its production. In addition, general public will insist to protect the natural radiation exposure as well as artificial one when we explain only the difficulty of controllability of natural radiation exposure, because consciousness of the cost or expense for radiation safety is low and fear of invisible radiation is strong. Therefore the reason of the distinction between gnaturalh and gartificialh radiation exposure is not only the controllability but also the responsibility of human being. Deep consideration from the aspect of ethics should be necessary in the ICRP draft.