Caden Anderson, 4, tested at a blood lead level above 20 micrograms last year. The high level triggered visits from a public health nurse for retesting, and his level has since gone down.

Caden’s grandmother, Anquanetta Williams, said her son also had lead poisoning as a child growing up in the city. Their home in north St. Louis is being repainted inside and out through the city’s Lead Safe Work Project. Williams said she is aware of the hazards from lead because of her work in a child care center.

“I think it’s a good program. They’re sure willing to help you out,” Williams said. “I don’t want him to get sick.”

Lead poisoning reached epidemic levels nationwide in the 1970s when gasoline and paint still contained lead. By the late 1990s, there was a big push to clean up the residual lead in houses and soil.

In 2003, St. Louis Mayor Francis Slay vowed to eradicate lead poisoning by 2010 through increased testing and remediation projects. The city hired a consultant from the Coalition to End Childhood Poisoning in Baltimore, and the efforts were successful.

In the 1990s, about one in four St. Louis children had lead poisoning. By 2011, the rate dropped to one in 50. But the improvements have slowed.