Low-background steel

[3][4] Since the end of atmospheric nuclear testing, background radiation has decreased to very near natural levels,[5] making special low-background steel no longer necessary for most radiation-sensitive uses, as brand-new steel now has a low enough radioactive signature that it can generally be used.

[6] Some demand remains for the most radiation-sensitive uses, such as Geiger counters and sensing equipment aboard spacecraft.

[7] Andrew Brockman, a maritime crime researcher and archaeologist, argues that it is more likely to be conventional salvage.

Present-day air carries radionuclides, such as cobalt-60, which are deposited into the steel, giving it a weak radioactive signature.

[6] Another source of radioactive contamination was the coating of steel cauldrons in cobalt-60 in order to monitor wear.