> steel smelting processes that do not introduce air into the steel. Air is perfectly fine. Both Oxygen and Nitrogen do not stay radioactive for longer than a

> steel smelting processes that do not introduce air into the steel. Air is perfectly fine. Both Oxygen and Nitrogen do not stay radioactive for longer than a few seconds. It's CO2 that is the problem, specifically the carbon. And of course any other random impurity. They could just use cryogenicaly distilled air, and take the nitrogen-oxygen part (the boiling points are very close).