The harmful effects of lead to ADULTS are, in my opinion, somewhat overblown. The real concern is children. There is no doubt that children who ingest lead are harmed by it. Their absorption is greater than adults, and the effects on developing neurological tissue and bone is more serious. Such ingestion comes from natural sources, for example eating mud, and from man-made sources, like eating flaking paint. Here is a fairly balanced review:
Lead poisoning - Wikipedia, the free encyclopedia It is definitely important that children be protected and the upper acceptable limit of 10 ug/dL is actually too high in the opinion of many American pediatricians.
Adults are different. Some use an acceptable limit of 10 ug/dL while others use the older limit of 25 ug/dL (see previous citation). About 30, 20, and 10 years ago, I did non-controlled studies of blood lead in young adults -- basically students in a toxicology class. Their blood levels were all considerably less than 5 ug/dL, including mine and other faculty who participated. I routinely use lead solder, leaded alloys in machining, and had exposure to leaded fuel and oil from engines using such fuel (aviation fuel). It should also be noted that lead bullets embedded in soft tissue for long periods cause no discernible increase in blood lead, unless the bullet is lodged near a bone. That is why surgeons may decide the risks of surgery do not justify removing them.
In summary, I think common sense and care in dealing with exposure to elemental lead is all that is needed for adults. Lead solder has advantages over lead-free solder. It is a risk/benefit type of issue. If you use it, wash your hands afterward, particularly before eating. If you are doing a lot of soldering, with or without leaded solder, be sure there is good ventilation. The fumes from the solder and flux are not good for you. And, don't do it in a place where children are likely to pick up pieces of solder and eat them.
John
Sorry, it took me too long to write my reply.