Exposed to lead? Heck I machine it.
What do you think SAE660 bearing bronze contains.
This level of hype is horribly misguided.
I have not witnessed one machinist harmed by lead in 40 years.
If I cared I would wear a face mask when working with bronzes.
Truthfully Hexavalent Chromium exposure from stainless scares me more.
That is a known carcinogen and I machine alot of high Chrome content stainless.