CHICAGO (CBS) — What did they know, when did they know it and, the biggest question, when did parents finally find out?

We’re referring to lead exposure in Cook County Public Housing and, as CBS 2’s Dorothy Tucker reports, subsequent missed deadlines.

The main building of the Vera L. Yates Homes, which are part of the Housing Authority of Cook County (HACC), is a hub of activity for the children in its complex. However, inside the community center, where the after school program is held, lead levels nearly twice the acceptable limit were found in the window last year.

Parents, such as Sondra Bearden, had no clue until CBS 2 informed them.

“Wow, it’s like — wow,” Beardon said, who is a Yates Homes resident. “That’s, like, a really low blow to me. My son just turned six this year — just turned six a month ago.”

Children under the age of six are among those most susceptible to lead, as it can impact the brain growth.

Jeannie Perry’s four-year-old daughter also attends the daycare center. Since dust can travel through the air, she worries her daughter may have been exposed to lead.

“I’m upset, I’m really upset. Now I have to call my daughter’s doctor so she can go get checked out. So I’m upset,” Perry said.

In the Spring of 2016, the HACC began randomly testing at all five of its complexes. The lead at the community center was discovered as a result.

Loretta Warren, a Richard Flowers Homes resident, said, “They tested the whole house, windows, walls — everywhere.”

Residents with high levels are supposed to be notified 15 days after the results. While results arrived at Yates May 31st, residents weren’t notified until they received a letter dated November 1. Instead of two weeks, the HACC took two months to notify residents. And at Flowers Homes, some units had lead dust six times above federal limits.

“I’m not arguing the fact that we may have missed a deadline, I’m not,” said Richard Monocchio, who is the executive director at the HACC. “I’m taking full responsibility for actually doing the remediation — that’s the important thing. We cleaned it.”

At Yates, though, they missed a cleanup deadline by two months for units with children under six.

“It took us a while to figure out the best and most cost effective way to remediate the issue,” Monocchio contended.

Barbara Barnes, a mother of two, says she is satisfied with the cleanup, but still worries about the years she didn’t know her home was contaminated. She received a letter saying the test was positive.

Cook County Public Housing’s chief spokesperson, Frank Shuftan, issued the following statement:

“President Preckwinkle’s commitment to residents of the Housing Authority of Cook County is to provide them with safe, dry and warm homes, either in our own buildings or through vouchers. We take that commitment seriously as does the leadership of HACC, and we are reviewing all practices and protocols currently in place,” Shuftan wrote in a prepared statement.

“Under President Preckwinkle’s administration, HACC has rehabilitated nearly 1,000 units of housing throughout Cook County, and HACC will continue this aggressive approach to improving living conditions for our residents. We take seriously the need to ensure that all of our facilities are thoroughly clean and healthy places to live, and that any potentially dangerous substances are removed.”

The day care center recently did its own testing and did not find high levels of lead in their section of the building.