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.
Blood lead level that may result in lead poisoning or an elevated blood lead level. For example, a child can ingest lead by chewing on a toy that is made of lead-contaminated metal or is painted with lead-contaminated paint. A major source of exposure to lead comes from inhalation. Factories and industries, vehicle exhaust (especially from vehicles using leaded gasoline), and even dust in the air that people breathe all have the potential of containing lead. Other major sources of lead exposure include ingestion and contact with products such as paint and soil that may contain lead. Many older claw-foot bathtubs have also