RE: Can breathing in solder be dangerous?HELP
... you've only got one body, don't take preventable risks with it.
I know guys that smoke and drink and die at 100 and guys that have no bad habits and excercise that had a heart attack at 55 but... these are usually the exception.
Well ventilated area and wear a mask if you have one, or buy one for $25 from my link above. Breathing in fumes is never good for you regardless of where it comes from.