It is used in a wide range of products, including batteries, paint, ammunition and various metal products. Lead exposure results from inhaling air, drinking water, or ingesting foods or soil that contain lead. Children may be exposed to lead by swallowing chips of paint that contain lead a surprisingly common occurrence. Until recently, the largest single source of lead in the air was vehicle exhaust. Currently, key sources include emissions from iron and steel production, smelting operations, and lead-acid battery manufacturers.
Cigarette smoke is also a source of lead.
Most of the lead in water is from lead plumbing and solder in houses and other buildings, lead-contaminated dust and soil carried into water by rain and wind, and wastewater from industries that use lead. Lead in soil often comes from lead-contaminated wastes in landfills and from fertilizers. Because plants can absorb lead from contaminated soil, food may contain lead as a result. Lead exposure stems primarily from contact with contaminated dust or water. Lead has been found at over 800 Superfund sites.