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Lead-Safe Wisconsin: What is Lead Poisoning?

Children sitting outside smiling

What is Lead?

Lead is a naturally occurring element found in small amounts in the earth’s crust. It was mined in Wisconsin and added as a stabilizing agent to products like:

  • Gasoline
  • Paint
  • Plastics
  • Varnish

What is lead poisoning?

In 1978, lead was banned from being added to paint and varnish for residential use because researchers found it can be toxic to humans and animals. It can damage the brain and other systems, leading to:

  • Developmental delays.
  • Learning disabilities.
  • Reduced IQ and attention span.
  • A range of other health and behavioral effects.

Lead is still present in paint and varnish in homes and child care centers built before 1978. Lead can hurt anyone, but kids under age six are most vulnerable. The damage from lead poisoning can last a lifetime. Learn more about how lead affects the mind and body by expanding the sections below.

Lead poisoning in children can result in delays in growth, behavior, and learning. Every child exposed to lead should be screened for harmful neurocognitive effects. Screening can help determine which interventions may be necessary.

Studies have found lead poisoning can cause:

Lead poisoning can harm these bodily systems:

  • Cardiovascular
  • Cognitive
  • Endocrine
  • Immune
  • Musculoskeletal
  • Reproductive

Studies have found it can cause:

How does lead poison?

Lead poisoning occurs in a few common ways:

  • Lead-tainted dust can get on children’s hands and into their mouths. This can happen because chipping and peeling lead-based paint in older homes is ground to a very fine dust and largely invisible. It can gather in windows, on floors, porches, and in the soil.
  • Lead-based paint can be disturbed during renovations or remodeling. If the work is not conducted safely, the lead fumes and dust in the air can be inhaled or ingested by people in the area.
  • Lead can also be found in:
    • Drinking water service lines and fixtures.
    • Soil from leaded gasoline.
    • Paint and industrial emissions.
    • Products such as toys, children’s jewelry, candies, and traditional remedies, like powders for arthritis.

How do we define lead poisoning?

In 2021, the CDC (Centers for Disease Control and Prevention) updated the blood lead reference value to 3.5 micrograms per deciliter (µg/dL). This level helps public health authorities identify children with higher levels of lead in their blood compared to most children. The value was previously 5 micrograms per deciliter.

Find data on childhood lead poisoning in Wisconsin based on the blood lead reference value.

Find health care guidance for lead-poisoned children.

When should children get tested for lead poisoning?

Children at risk for blood lead poisoning should get a blood lead test at ages one and two years old. Children at risk should get a blood lead test between ages three and five years old if they have not had one before. Children living in the city of Milwaukee or city of Racine should get blood lead tests more often than children living in other cities.

A child should get tested for lead poisoning if any of the following apply:

  • They live in the city of Milwaukee or city of Racine.
  • They use Medicaid or BadgerCare.
  • They use the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).
  • They don't have insurance.
  • They spend time in housing built before 1950.
  • They spend time in housing built before 1978 with recent or ongoing renovations.
  • They have a sibling or playmate with lead poisoning.

To learn more about blood lead testing, visit the Lead-Safe Wisconsin: Pediatric Lead Testing and Reporting page.

How can we prevent lead poisoning?

We can prevent lead poisoning by getting rid of the danger before it harms children or others. Wisconsin’s goal is to eliminate the disease by making houses lead-safe, and by getting involved early to stop lead exposure.

Learn about prevention and intervention for childhood lead exposure.

Learn about lead-safe renovation in Wisconsin.

More resources

Families and health professionals can find fact sheets and other educational resources on our Lead-Safe Wisconsin: Tools for Outreach page. Visit our Lead-Safe Wisconsin: Forms and Publications page for additional lead-related publications.

Reliable sources for more information

Last revised October 11, 2023