Lead

In the past, lead was in common use in buildings.  In fact, the chemical symbol for lead is Pb, from the Latin plumbum.  This is the word from which "Plumber" is derived.  Plumber used to mean "lead-worker", since lead pipes were used extensively in plumbing systems.

Health hazards associated with lead were documented in the 1890s.  But legislation to ban lead from common building products was not passed until much later.

The "exposure routes" for lead are inhalation (breathing) and ingestion (eating).

The use of lead in solder was banned in 1988.  The use of lead in paint was banned in 1978.  The concern with solder is that the water can leach out the lead in the form of lead salts, which can be ingested.  The concern with paint is that it can be ingested by children through contact with paint dust or chips, or be inhaled as dust.

IDEA does not test for lead.  The reason we don't is because if you if the house was built before 1978, the paint most likely contains lead.  If it was built before 1988, any solder joints in copper piping most likely contain lead.

Just because you have lead in your house, does not mean that there are imminent health issues.  However, there are some precautions that you should take: