Public Advocate Bill de Blasio’s campaign against charter school operator Eva Moskowitz continued today when the mayoral candidate called for an independent investigation into the way the city treats Moskowitz’s Success Academy schools.

Citing a column by Juan Gonzalez in Friday’s New York Daily News, de Blasio said Cobble Hill Success Academy had toxin-ridden light fixtures removed before other schools in its Brooklyn public school building. (The city is in the midst of a lumbering process to rid hundreds of school buildings of lights that contain PCBs.)

De Blasio brought students and parents to the steps of the Department of Education’s headquarters on Chambers Street today to call for an investigation into what he said was preferential treatment by the department of the charter network. He got an assist from the United Federation of Teachers, who wrote to city schools Chancellor Dennis Walcott today to ask for the investigation.

“The bottom line is if we ever had to have an example of inequality in our city laid out before our very eyes, this is it,” de Blasio said at a press conference Monday afternoon. “It’s time for Eva Moskowitz’s privilege and power to end.”

But Success Academy and Department of Education officials dispute Gonzalez’s reporting and de Blasio’s claims. They say no school in the Baltic Street building has been cleared of PCBs yet and note that the city made capital improvements to the three other schools in the building at the same time as Success Academy prepared to move in last summer.

“Bill de Blasio didn’t do his homework before calling his press conference,” said Success Academy spokeswoman Jenny Sedlis. “It’s disappointing that the public advocate is asking taxpayers to foot the bill for an investigation based on erroneous claims without first trying to get any of the facts himself.”

A teacher in the building who has posted occasional photographs of the building as it went from housing three schools to four wrote in December that Success Academy had replaced its light fixtures just before school started in September.

It wasn’t the first time that de Blasio had singled Moskowitz out. At a mayoral debate in January, de Blasio said, “Another thing that has to change starting in January is that Eva Moskowitz cannot continue to have the run of the place.” He added, “She was giving the orders and chancellors were bowing down and agreeing. That’s not acceptable.”

But de Blasio said the status of Success Academy’s light fixtures represented a bigger equity issue that he would address as mayor.

“If you’re going to make a charter school safe in a school building then all the traditional public schools need to be safe as well to the same standard,” he said at the press conference. “We should end the practice of favoring certain charters — giving them the ability to co-locate whether they fit a school or not. That’s why I’ve called for a moratorium on colocations and closures until we come up with a fair policy.”

Other mayoral candidates have grappled with the tensions of charter school co-locations, as well. Like de Blasio, Comptroller John Liu has made calling for a moratorium on charter school co-locations a key part of his education platform. Former comptroller Bill Thompson has said charter and district-run schools should be able to share space, but the city’s process for awarding and enhancing space needs to change. City Council Speaker Christine Quinn has also said co-locations are important to allow charter schools to continue to flourish, but she, too, has said the process could be improved.

Each of the Democratic candidates has been angling for months to please the UFT, which will endorse a candidate this summer before the party primary. Union officials said the process to choose a candidate would begin soon after the union’s internal elections are complete at the end of this month.