Which type of tungsten produces radioactive dust when ground?

Thoriated tungsten produces radioactive dust when ground due to the presence of thorium, which is a naturally occurring radioactive element. When thoriated tungsten electrodes are machined or ground, tiny particles of the electrode can become airborne, potentially exposing workers to low levels of radiation. This is due to the alpha radiation emitted from the decay of thorium, which, although not highly penetrating, can still pose health risks if ingested or inhaled over time.

The other types of tungsten electrodes do not contain radioactive materials. Pure tungsten is simply tungsten without any alloying elements, making it safe to grind without producing radioactive dust. Zirconiated tungsten contains zirconium, which enhances the electrode's performance but does not introduce radioactive hazards. Similarly, lanthanated tungsten contains lanthanum, another non-radioactive element. Thus, thoriated tungsten stands out among these options for its association with radioactive dust generation during grinding.