This video explains the situation quite nicely:
- The fumes don’t contain led or tin as you’d need the higher temperature to evaporate those elements
- What evaporates is flux and you shouldn’t breathe it in
- Toxicity for hobby use is quite low and you won’t feel any effects. Although, it’s better not to breathe flux fumes directly.
EXTRA TIP: do not eat solder
Here in MAKERbuino HQ, we have a few cheap solder fume extractors for soldering purposes.
If you’re soldering once a month, you probably do not need to buy an extractor, just vent the room while soldering.
I hope this answers your question