Ah, that something new I learned. So does most solder have lead elements in it?
Solder for most things electrical is 37-40% lead. Solder for drinking products is now lead free, but was not in the past.
The ROHS initiative is trying to remove lead from electrical goods, but lead has good melting properties and helps prevent the tin component in solder from migrating and forming stress whiskers which could bridge and create shorts. Lead is just one of those things that's dangerous but highly useful.
edit: Tin whiskers https://nepp.nasa.gov/whisker/background/index.htm
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