Health A-Z

Medical Content Created by the Faculty of the Harvard Medical School


What Is It?

Lead is a metal that is poisonous (toxic) when inhaled or eaten. Lead gets into the bloodstream. It is stored in the organs, tissues, bones and teeth.

With increasing or prolonged exposure, lead can cause:

  • Permanent damage to the central nervous system, especially the brain

  • Delayed development in children

  • Behavioral changes in children

  • Decreased production of red blood cells (anemia)

  • Hearing problems

  • Damage to the reproductive systems of men and women

  • Kidney disease

  • Convulsions (seizures)

  • Coma

The leading source of exposure to lead is lead-based paint. This was outlawed for residential use in 1978. But it remains in some older homes. The main hazard is paint dust. Paint dust enters the air when old paint is scraped, sanded or begins to flake.

People can get lead into their bodies in other ways. These include:

  • Drinking water from pipes that are made of lead or use lead solder

  • Using ceramic dishes made with lead

  • Using products made with lead-containing paint (often imported from other countries)

  • Playing in lead-contaminated soil

  • Using lead in hobbies or crafts such as making stained glass

  • Using certain home remedies that contain lead

  • Eating lead-contaminated spices purchased in foreign countries (unusual)

Children face the most serious risk. Their growing bodies absorb more lead. Young children, especially toddlers, tend to put objects in their mouths that may be covered with lead dust. If lead paint is flaking, small children sometimes eat the sweet tasting paint chips. Or they chew on painted surfaces, such as window sills.

Adults who have high lead levels in their blood usually were exposed in the workplace. Industries with a high potential for exposure include:

  • Construction that involves welding, cutting, blasting or other disturbances of surfaces painted with lead

  • Smelter operations

  • Radiator repair shops

  • Firing ranges

Young children can be exposed to lead when parents who work in these areas carry lead dust home on their clothes and shoes.

A woman who had lead poisoning can pass lead on to her fetus if she becomes pregnant. This remains true even if she no longer is exposed to lead.

Since lead was banned in gasoline and residential paint, average blood levels of lead have dropped dramatically in the United States.

In children, lead levels of 5 micrograms or more per deciliter (mcg/dL) of blood are known to be hazardous. Recent studies suggest that even lower levels may be harmful. Pediatricians closely monitor children whose lead level is approaching 5 (mcg/dL). They are encouraged to look carefully for possible sources of lead exposure.

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From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.

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