I'm with the cautious bullet casters who wear correct respirators and deploy vigorous ventilation. Lead is everywhere. Until 1974 our automobiles were spewing tetraethyl lead all over the highways. I did metallurgical assay work as a grad student to earn a few extra $$. My university had state of the art neutron activation analysis gear that would non-destructively generate spectra on any substance. We discovered that soil samples taken near any roadway had high levels of lead from decades of exhaust broadcast. Aviation gasoline still uses lead, but the quantities are miniscule compared to the motor gasoline pool through the years. We're all probably 5 I.Q. points lower than we should be.