https://en.wikipedia.org/wiki/Cobalt-60 Steel contamination Cobalt is an element used to make steel. Uncontrolled disposal of 60 Co in scrap metal is responsible for the radioactivity found in several iron-based products.[13][14] Around 1983, construction was finished of 1700 apartments in Taiwan which were built with steel contaminated with cobalt-60. Approximately 10,000 people occupied these buildings during a 9–20 year period. On average, these people received a radiation dose of 0.4 Sv, unknowingly. This large group did not suffer a higher incidence of cancer mortality, as the linear no-threshold model would predict, but suffered a lower cancer mortality than the general Taiwan public. These observations appear to be compatible with the radiation hormesis model.[15] Repeat after me "real life is not like fallout the videogame"