The effects of lead poisoning depend on age, how much lead and for how long, but official health agencies agree on the main ones. In children, lead harms the developing brain and nervous system, with effects on learning, attention and behavior; in adults, it is linked to higher blood pressure, kidney damage and fertility problems, and some effects in both can be permanent.
In short: the CDC says no safe blood lead level in children has been identified, and the World Health Organization says there is no known safe blood lead concentration. Even low levels in children are associated with lower IQ scores and school achievement and with attention and behavior problems, according to the CDC and NIEHS. In adults, NIEHS links levels below 10 µg/dL to higher blood pressure and reduced kidney function, and NIOSH lists anemia, nerve and brain damage and infertility at high exposure. Because damage may not be reversible, prevention and early testing matter most. If you are worried, talk to a doctor or your local health department, or call Poison Control at 1-800-222-1222.
This page explains what the CDC, the National Institutes of Health (through NIEHS and its National Toxicology Program), NIOSH and WHO publish. It is not a diagnosis or medical advice. For an overview of the topic, start at our lead poisoning hub.
Lead toxicity: why lead harms the body
Lead toxicity is the medical term for the harm lead does once it is inside the body. Lead travels in the blood, reaches the brain, kidneys and other organs, and is stored in bones and teeth, the WHO explains. Stored lead can move back into the blood years later, for example during pregnancy, and reach a developing baby.
Doctors measure exposure with a blood lead test, reported in micrograms per deciliter (µg/dL). The CDC’s blood lead reference value for children is 3.5 µg/dL. That number marks the top 2.5% of US children aged 1 to 5; it is a screening tool, not a line below which lead is harmless.
Effects of lead on children
Children are the main concern for three reasons the CDC and WHO describe: they put hands and objects in their mouths, so they swallow more dust and soil; their bodies absorb more of the lead they swallow than adults do; and their brains are still developing. Children under 6 are the most likely to be exposed, the CDC says.
The CDC lists these effects of lead exposure in children:
- Damage to the brain and nervous system
- Slowed growth and development
- Learning and behavior problems
- Hearing and speech problems
The CDC adds that these can show up as lower IQ, a shorter attention span and doing less well in school. The WHO describes reduced attention span and increased antisocial behavior, and says lead exposure in children also causes anemia, high blood pressure, kidney problems and harm to the immune and reproductive systems.
Most of this happens quietly. The CDC says most children with lead in their blood have no obvious immediate symptoms, which is why testing matters more than watching for signs. Our lead poisoning symptoms guide lists the signs that do appear, mostly at higher levels, and our lead and children guide covers screening ages and prevention.
Effects at low levels
NIEHS, part of the NIH, summarizes the research by blood lead level. It says health effects in children are found at levels below 5 µg/dL and may include lower IQ scores and academic achievement, and that levels at or below 10 µg/dL are associated with more behavioral effects and delayed puberty. The National Toxicology Program’s 2012 review of low-level lead concluded there is evidence of harm in both children and adults below 10 µg/dL and, for some effects, below 5 µg/dL.
These are associations found across many studies of groups of people. They describe risk across a population; they cannot predict what will happen to one particular child. A child’s doctor is the right person to talk to about a specific result.
Effects at very high levels
At very high levels, lead can cause severe illness. The NIH’s MedlinePlus lists vomiting, a staggering walk, muscle weakness, seizures and coma. The WHO says children who survive severe lead poisoning may be left with permanent intellectual disability and behavior disorders. These are medical emergencies: call 911.
Effects of lead on adults
Most adults with high blood lead are exposed at work, according to NIEHS, in jobs such as construction, mining, welding and battery manufacturing. Others are exposed through home renovation, hobbies or contaminated products.
| Body system | What official sources say |
|---|---|
| Heart and blood pressure | NIEHS: levels below 10 µg/dL are associated with increases in blood pressure; above 15 µg/dL with cardiovascular effects. WHO: increased risk of high blood pressure and cardiovascular problems. NIOSH lists heart disease. |
| Kidneys | NIEHS: levels below 10 µg/dL are associated with decreased kidney function, and even below 5 µg/dL may decrease it. WHO and NIOSH list kidney damage. |
| Brain and nerves | NIOSH: high exposure may cause neurologic and brain damage; long-term exposure can bring depression, irritability, mood changes, distraction and forgetfulness, and pain or tingling in the hands or feet. |
| Reproduction | NIOSH: infertility in both men and women. NIEHS links levels above 15 µg/dL to fertility problems. |
| Blood | NIOSH and ATSDR: anemia. |
| Other | NIOSH also lists hearing damage, decreased lung function, bone or tooth loss and more infections, and says lead is possibly linked to cancer. |
NIOSH notes that these effects are the same whether lead is breathed in, swallowed or absorbed through the skin, that symptoms look like those of other illnesses and may develop slowly, and that very high exposure can kill. If you work with lead, tell your doctor.
Effects during pregnancy
Lead crosses the placenta. The CDC says lead stored in a mother’s bones can be released into the blood during pregnancy, and that lead exposure in pregnancy can raise the risk of miscarriage, of a baby being born too early or too small, and of harm to the baby’s brain, kidneys and nervous system. NIEHS says maternal blood lead levels even below 5 µg/dL are associated with reduced fetal growth, and the WHO lists reduced fetal growth and preterm birth. If you are pregnant and think you may have been exposed, the CDC’s advice is to talk to your health care provider.
Long-term effects of lead poisoning
The official wording here is careful, and so are we. What the agencies say:
- CDC: “The effects of lead poisoning can be permanent and disabling.”
- WHO: lead can permanently affect children’s brain development, and lead causes long-term harm in adults, including increased risk of high blood pressure.
- NIEHS: many effects are permanent, and research suggests some psychological effects of childhood exposure may not appear until adulthood. NIEHS-funded research has also linked early-life lead exposure with psychiatric disorders and substance abuse.
- WHO, worldwide: citing estimates from the Institute for Health Metrics and Evaluation, more than 3.5 million deaths in 2023 were attributed to lead exposure, mainly through effects on the heart and blood vessels.
A few cautions help read this research well. Many long-term findings come from studies that follow groups of people over time, and they show links, not certainty for any one person. Global death estimates are models, and they include countries with far higher exposure than the US. And lead stored in bone means that exposure in the past can still matter today, which is one reason doctors ask about old jobs, hobbies and homes.
Can the effects be reversed?
Blood lead levels can come down once the source is removed, and doctors can treat very high levels. But treatment does not undo damage that has already happened, and the CDC and WHO both describe some effects as permanent. That is why the CDC’s follow-up for children includes early educational services and developmental checks alongside removing the lead. Our guide to lead poisoning treatment explains what doctors and health departments do at each blood lead level.
Why prevention matters most
Because damage may be permanent and often has no symptoms, the CDC’s approach is to remove lead hazards before a child is exposed, which it calls primary prevention. In most US homes that means:
- Old paint and dust. Homes built before 1978 probably contain lead-based paint, the CDC says, and peeling paint and renovation dust are the most common hazards. See lead paint testing and dust and soil testing.
- Water. Lead pipes, solder and some brass fixtures can add lead to tap water. See lead in water testing.
- Products. Some imported spices, candies, remedies, cosmetics, pottery, toys and jewelry. See lead in household items.
- Work and hobbies. Lead dust carried home on clothes, shoes and hair.
Our guide to lead poisoning causes and prevention covers each source and the CDC and EPA steps in detail. When a home needs inspection or repair, use a certified professional from our directory.
Frequently asked questions
What are the long-term effects of lead poisoning?
In children, official sources describe lasting effects on learning, attention, behavior and development; in adults, higher blood pressure, heart and kidney problems and fertility effects. The CDC says effects can be permanent. How a specific person is affected depends on the level and length of exposure.
Is lead toxicity the same as lead poisoning?
The terms are used for the same problem: harm from lead in the body. Health agencies also talk about lead exposure, meaning any lead taken in, since no safe level has been identified in children.
Can a small amount of lead cause harm?
NIEHS says health effects in children are found below 5 µg/dL, and the CDC says no safe level in children has been identified. That is why doctors take any detectable level seriously and look for the source.
Do adults recover from lead exposure?
Blood levels fall once exposure stops, but lead stored in bone can stay for years, and some effects may last. An adult with possible exposure should talk to a doctor, who can order a blood test and advise on follow-up.
How do I know if my child has been affected?
Only a blood test shows exposure. Ask your child’s doctor or your local health department. If your child may have swallowed something with lead, call Poison Control at 1-800-222-1222; for severe symptoms such as a seizure, call 911.
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