More than 900 classrooms in New York City public schools tested positive for lead in recent months, according to data released by the city's Department of Education.

The presence of lead-based paint and visible deterioration was found in 938 classrooms, according to the inspection by the city of more than 5,400 classrooms in nearly 800 schools built before 1985. Officials found deteriorating lead paint in 302 of the schools and deteriorating paint in 2,245 classrooms.

The findings were the result of typical end-of-year wear and tear, according to department officials, and will be fixed by the start of the school year. The inspections follow a local news investigation that found dangerous levels of lead in four schools.

"These inspections were done at the end of the year when classrooms have been used all year and are transitioning out and teachers are taking down posters," says Miranda Barbot, the first deputy press secretary for the New York City Department of Education. "It wouldn't be uncommon for there to be this type of wear and tear in the classroom."

Barbot says the city has always done regular inspections year-round and that the release of the data is the first step in implementing a reporting system that will be made public three times a year.

"We are moving toward a more formal reporting structure and creating transparency for parents," she says, adding that the department recently launched an online notification portal for parents and others in the school community.

"Any sort of peeling paint in the classroom would have been addressed, and it's work that we would have been doing before the first day of school anyway," Barbot says.

In addition, inspection reports obtained by Chalkbeat, show that 80% of roughly 500 examined buildings contained at least one faucet with elevated lead, though officials said those issues have already been addressed.

The findings were released just hours before New York City Mayor Bill De Blasio took the stage for a Democratic primary debate in Detroit, where he was asked about the city's public housing testing positive for elevated levels of lead and why he's the right person to handle the issue of removing lead not just in public housing facilities but also in schools.

"We have a huge problem and it's decades-old in New York," he answered. "But here's what we've done about it: We've declared the eradication of all lead – literally ending the notion of lead poisoning once and for all – as the goal of our administration."

He noted that lead exposure has decreased by 90% in New York City since 2005.

"We're doing something about it," he said. "We're going to go into every place – buildings, schools, public housing – to take out that lead, remediate that lead once and for all. And that needs to be done all over this country."

Notably, de Blasio has come under fire during his tenure for not prioritizing lead paint inspections in public housing facilities. The criticism has spanned the administrations of previous mayors and has gotten so bad that the federal government recently appointed an independent monitor to oversee the city's public housing authority.

"I'll tell you what you do when you're actually in charge of something," he said. "I'm in charge of the largest city in this nation. You do not accept the status quo. You fix it. We are going into every one of those apartments to make sure those children and those families are safe. There should be a federal mandate to do the same for Flint, for Detroit, for every place in this country."

During the exchange, Julian Castro, the former secretary of Housing and Urban Development, pointed out that he announced a $50 billion plan to remove lead from schools during a visit to Flint, Michigan, six weeks ago.

"A lot of people don't know this is still a big problem," he said.

Public interest and outcry over lead contamination has surged in the five years since the disaster in Flint, where local cost-cutting measures resulted in a tainted and dangerous drinking water supply.

A report published last week by the federal Government Accountability Office found that about a third of public school students, about 15.3 million, were enrolled in school districts that inspected for lead paint and that about half of the districts found lead paint.

The most common source of lead exposure for children, according to the GAO report, comes from paint in buildings built before 1978 – the year the government banned the sale of lead-based paint. The exposure most often occurs when lead dust is released into the air after disturbing lead paint during renovations, when lead paint deteriorates or when soil is contaminated with lead.

The GAO report found that the extent to which children are exposed to lead has been substantially reduced since the 1970s, but approximately 3.6 million families with a child under the age of 6 still live in a home with one or more conditions that can expose them to levels of lead that the Environmental Protection Agency considers hazardous.

According to the Centers for Disease Control and Prevention, no safe blood lead level in children has been identified.