Lead is a toxic metal. In adults, lead poisoning happens when levels of lead in the blood increase. The Occupational Safety and Health Administration (OSHA) requires that workplaces take action when a worker’s blood lead level is too high. This means more than 25 micrograms per deciliter (mcg/dL) in the blood. Lead is very common in the environment. As a result, most adults have some level of this metal in their blood and body tissue.

Experts believe that no level of lead in the body is safe for children. Concern about lead poisoning in children occurs when lead reaches a level of 10 mcg/dL in the blood. Levels of 20 mcg/dL or more represent actual lead poisoning. This can lead to:

Lower levels of blood lead (probably below currently accepted "safe" levels) can lead to learning and/or behavioral difficulties. They can also delay puberty in boys.

Lead can be absorbed into the bloodstream by eating, drinking, or breathing contaminated particles.

Lead is used in many industrial processes and within the home. It can be found in:

  • Paint
  • Dust
  • Soil
  • Drinking water
  • Food (rarely)

Most homes built before 1960 contain some lead-based paint. This was banned from residential use in 1978. Dust containing lead can linger on windowsills and in window wells. Drinking water that travels through lead pipes, or through pipes with lead-based soldering, may also be contaminated. Lead can become mixed with dirt after it peels from paint on building exteriors. Industrial sources and car exhaust also contribute to the problem. Lead levels in the air have dropped a lot since lead additives were banned from gasoline in the 1970s. Food produced outside of the United States can be contaminated if packaged in lead-soldered cans.