Seriously, though. Everything is radioactive since the 1940s. Yeah, steel is a particularly interesting case due to the amount of air used through the process.

Seriously, though. Everything is radioactive since the 1940s. Yeah, steel is a particularly interesting case due to the amount of air used through the process. https://en.wikipedia.org/wiki/Low-background_steel https://en.wikipedia.org/wiki/Low-background_steel talks about the problems this cause.