Mayor Bill de Blasio has insisted that no children have been harmed by lead poisoning in the City's public housing complexes, and even after federal prosecutors detailed last month that at least 19 children had suffered from lead poisoning in NYCHA buildings, the mayor insisted that those were just "allegations." But on Saturday the Daily News reported that from 2012 through 2016, NYCHA knew of 820 children who tested positive for high levels of lead poisoning.

These children had lead in their blood between 5 to 9 micrograms per deciliter, the range where the CDC recommends government intervention. "During the Bloomberg administration and continuing under de Blasio, the city chose to ignore the CDC recommendation and use a higher trigger of 10 micro-grams per deciliter before notifying NYCHA and inspecting apartments," reports the Daily News.

Olivia Lapeyrolerie, a spokesperson for the mayor, told the Daily News, "The CDC recommends each city respond to each case, but leaves it up to each jurisdiction to determine that response." Lapeyrolerie also told the Times that the Health Department sent detailed letters to the parents and health care providers of the children who were affected.

Eric Phillips, another mayoral spokesperson, said that the city has since lowered the testing threshold to 5 miligrams for NYCHA housing at the recommendation of federal housing officials. Other mayoral employees defended the administration on Twitter:

But even at 5-9 micro-grams, lead in the blood can cause significant development issues. The New York Times reports:

A 2005 study concluded that increasing a child’s blood lead level to 10 micrograms from 2.4 translated to a 3.9-point drop in I.Q. A 2015 study of Chicago elementary school students concluded that blood lead concentrations of five to nine micrograms explained up to 15 percent of failing grades in reading and math.
Even tiny increases, below five micrograms, “are associated with significant decrements in performance on standardized tests,” the researchers said.

Last October, Corey Stern at the law firm Levy Konigsberg filed a class action lawsuit representing 20 tenants affected by lead poisoning. "Our mayor has been steadfast in his position that no child was injured on his watch, and he has now been proven to be delusional or a liar," said Stern, quoted in the Daily News.

In a statement, City Comptroller Scott Stringer said, “This deception must end today," and vowed to investigate the City's actions.

Since 2016, federal prosecutors have been investigating whether NYCHA was conducting lead paint inspections (it wasn't) and whether it was filing false paperwork claiming that it was conducting these inspection, to receive federal funds (it was). Back in June, the city agreed to pay $2 billion to NYCHA after admitting to widespread neglect and systematic misconduct in a range of issues, including mismanagement in the way it handled lead-poisoned children.

De Blasio called into NY1 on Monday afternoon to defend his administration.

"We have the best Public Health Department in the entire country and the have aggressively followed up in each case for years, and they published the data for years," de Blasio said, stressing that the overall number of cases have gone down, and that the majority of them aren't seen in public housing. "What hasn't been done is to separate the NYCHA cases which are clearly an absolute minority of the cases...they have not been published separately, we're gonna do that from this point on."