Chronic radiation is defined as the radiation received slowly or in a low-dose-rate from various sources. It is completely different in nature to the acute gamma or neutron radiation generated from the atomic bomb explosions that occurred in Japan at the end of World War II. Tantalizing insights from people living in higher-than-normal background radiation areas in the world and from nuclear energy workers receiving excess radiation over long years have suggested that chronic radiation might paradoxically be beneficial to humans. However, in the absence of an epidemiological study, it has been impossible to conclude whether chronic radiation is harmless or indeed beneficial to human beings. Fortuitously, an incredible Co-60 contamination incident occurred in Taiwan 21 years ago, which provided the data necessary to demonstrate that chronic radiation is beneficial to human beings.