Lead to that of primary lead; some refining processes may be skipped depending on the material recycled and its potential contamination. Of the sources of lead for recycling, lead–acid batteries are the most important; lead pipe, sheet, and cable sheathing are also significant. Contrary to popular belief, pencil leads in wooden pencils have never been made from lead. When the pencil originated as a wrapped graphite writing tool, the particular type of graphite used was named "plumbago" (literally, "act for lead" or "lead mockup"). Lead metal has several useful mechanical properties, including high density, low melting point, ductility, and relative inertness.
Lead poisoning bring lead dust home on clothes or skin and expose their children. Occupational exposure to lead increases the risk of cardiovascular disease, in particular: stroke, and high blood pressure. Lead may be found in food when food is grown in soil that is high in lead, airborne lead contaminates the crops, animals eat lead in their diet, or lead enters the food either from what it was stored or cooked in. Some lead compounds are colorful and are used widely in paints, and lead paint is a major route of lead exposure in children. A study conducted in 1998–2000 found