The Centers for Disease Control and Prevention (CDC) put out a paper last month called Educational Interventions for Children Affected by Lead. The document outlines health effects of lead on learning and development in children.

According to the CDC, at least 24 million homes have deteriorated lead paint and contaminated dust. Among those, around 4 million have children living in them. Half-a-million U.S. children ages 1 to 5 have blood lead levels above 5 micrograms per deciliter (µg/dL). Although no safe blood lead level in children has been identified, the CDC recommends public health actions be taken at the 5 µg/dL level.

Below is a table taken from the CDC’s newly-released paper indicating what happens to children at various levels of exposure to lead. It is for situations like this that the federal government issued its lead-paint rule.

Educational Services for Children Affected by Lead Expert Panel. Educational interventions for children affected by lead. Atlanta: U.S. Department of Health and Human Services; 2015.