Lead is dangerous in two ways:
1) When it enters your body at high velocity after a noisy bang.
2) When you get it in small portions over a long period (like from drinking leaded fuel).
The problem with lead is that, unlike other poisonous substances, your body doesn't get rid of it and stores it.
From my experience, the hot soldering-irons are a lot more likely to cause harm (burned skin) than the soldering plumb. Washing hands and not licking your fingers when soldering is a good thing to do tho.
