Cause

Lead poisoning is caused by swallowing or breathing lead-contaminated substances or by skin contact. Small children may get lead poisoning by licking, chewing, or eating lead paint on toys, jewelry, or woodwork such as windowsills. In 2007, the U.S. Consumer Product Safety Commission (CPSC) found high lead content in many children’s toys and jewelry made in other countries. For a complete list of recalled products, see the CPSC Web site at www.cpsc.gov.

Small children also may be exposed by breathing, swallowing, or playing in lead-contaminated dust, soil, or smoke.

Although lead poisoning can sometimes result from a single large dose of lead, it usually is caused by months or years of exposure. Because lead cannot be seen, tasted, or smelled, people usually do not know when they are being exposed. Nearly everyone has some lead in his or her body.

Before its harmful effects were realized, lead was used in most gasolines, paints, water pipes, food and drink cans, and many other products. For example, house paint made before 1950 often contained as much as 50% lead. Paint manufactured up until 1978 still contained lead. About one-quarter of all U.S. dwellings have lead paint hazards (such as very small pieces of old paint, or dust or soil that contains lead).¹

Environmental regulations have reduced sources of lead pollution, significantly reducing lead in paint, gasoline, plumbing systems, and food and drink cans. For example, in 1988 the Environmental Protection Agency (EPA) banned the use of lead solder and other leaded parts to connect plumbing to public water supplies. But lead does not break down, so any lead already present in soil or water will stay there unless it is physically removed.

Common sources of lead poisoning are:⁴

• Lead-based paint and dust in houses or buildings built before 1978. (Old paint chips and dirt are the most common sources of lead in the home.)
• Lead-soldered pipes, which contaminate water supplies.
• Work settings (such as mines and metal smelters) and jobs (such as manufacturing or using radiators, batteries, cable, or wires.)
• Soil that has been contaminated with lead from smelters, hazardous waste, or gasoline.
• Hobbies that involve lead, such as stained glass or pottery.
• Alternative medicines and supplements, such as some herbs and vitamins manufactured outside the United States.
• Cosmetics, such as facial powders made outside of the United States.
• Food that is stored in leaded crystal or in cans made with lead.
• Imported toys, crayons, and candies.
• Homemade liquor made in stills built with lead solder, especially "moonshine whiskey" made in the southern U.S.

A pregnant woman who is exposed to lead can pass it to her unborn baby.⁵ Lead can also be passed to a baby through the mother's breast milk.

A study focusing on children in an urban primary care clinic showed that iron-deficient children absorb greater amounts of lead than children with adequate iron intake. Though further study is needed, the results suggest that ensuring iron intake in high-risk populations may help decrease the amount of lead absorbed by children in these groups.⁶