ooterness
I’m an electrical engineer living in Los Angeles, CA.
Lead-based solder is preferred for high-reliability electronics (space, nuclear, military, etc.) because it’s easier to rework, easier to verify by visual inspection, and it’s not vulnerable to tin whiskers.
Here’s the relevant safety guides from Stanford and MIT.
In short, if you do a lot of soldering, there are long-term occupational hazards from both lead oxides and rosin. Both guides agree that the main hazards are the fumes (workstation should have a fume extractor or suitable filter) and residue on your hands (wash hands with soap and water before eating).
I couldn’t find any numbers on how much material is removed by washing, but every reference emphasized that soap and water are vitally important.
I saw that happen once in a big presentation.
There was a team of students presenting their work to ~200 people. Right in the middle, a pop-up says updates are finished and the computer needs to restart. It has a helpful 60-second countdown, but “cancel” is grayed out, so all they can do is watch.
I was only in the audience and I still have nightmares.