Administrators at Holy Angels Catholic School say workers doing maintenance on an older part of the school found dust with lead in it.

So the Chicago Archdiocese decided to close the school until Monday.

Holy Angels says it’s shutting its doors for four days while it can investigate the issue and start the cleaning process.

Principal Dr. Siobhan Cafferty wrote in a letter to parents: “The safety and well-being of your children, as well as our faculty and staff, is our most important priority.”

Anita Weinberg is with Loyola University’s Child Law Center and Lead Safe Illinois.

She says lead exposure is especially dangerous for young kids.

“The dust gets on their hands,” Weinberg said. “They put their hands in their mouths, they ingest dust that has lead in it.”

Weinberg points to one study that focused on Chicago elementary schoolers.

“The children who had been lead poisoned were far more likely [than their peers] to fail third grade math and reading tests, and fail third grade.”

Weinberg says most children are exposed to lead in the home, especially in poorer communities and communities of color.

Dr. Cafferty wrote to parents saying administrators hope to rid all lead dust from the school by April 4th, focusing on the school’s gymnasium.

In the meantime, they will move classes to a newer part of the school.

Ryan Katz is a news fellow for WBEZ - @ryangordonkatz