Lead-based paint and contaminated dust are the primary sources of lead exposure in U.S. children. Although lead-based paints were banned in 1978, many homes built before then still contain it. The deterioration of this paint creates hazardous dust. About 24 million housing units in the U.S. have deteriorated lead paint, and over 4 million of these homes house young children.

Children under 6 are especially vulnerable due to their rapid growth and tendency to put objects in their mouths, which may carry lead dust. Those at greatest risk are children living at or below the poverty line in older homes. Additionally, some racial and ethnic groups are disproportionately affected.

Under Illinois law, as of July 1, 2026, all Illinois children are to be tested automatically at 12 and 24 months. All children six years of age and younger are required to be assessed for lead exposure through the use of a questionnaire administered by a health care provider. Blood tests that come back with confirmed lead levels in excess of 3.5 micrograms per deciliter (μg/dL) require a public health intervention. This includes a home inspection to determine the source of the lead contamination. If lead is found, the inspector works with the resident to remove the sources of lead. In addition, a public health nurse will visit and educate the family on ways to protect children from the harmful effects of lead.