Fun fact, Hephaestus was not a blacksmith, he was a bronze smith.

The god was created before the Iron Age started.

There are several ways to make bronze, but one of the most common was arsenic bronze. It was much stronger than tin bronze, but also meant that you had to melt arsenic.

So yeah, bronze age smiths had short lifespans and crippling neurologic issues from toxic metal inhalation.