New York City will remove light fixtures containing the toxic PCBs over the next 3.5 years, well ahead of its original end date of 2021. More than 600 school buildings still have the old fixtures.

After the city’s law department said the D.O.E. would replace old light fixtures containing PCBs “well before” its original deadline of 2021, frustrated parents, advocates and elected officials said they want details.

An old florescent light fixture broke, and the smoke not only forced the evacuation of the building but also re-ignited the fight over how to replace toxic fixtures in the schools as quickly as possible.

Education officials said they can remove toxic PCBs from about 85 schools this summer and a handful more next summer, a pace that City Council members said they found unacceptable.

A ruling from the state’s highest court makes clear that the School Construction Authority must outline its plans for long-term monitoring of and protection from toxins at once-contaminated properties that house school buildings, and communicate them to the public.

New York will be accelerating work on infrastructure projects, including PCB clean-up in city schools. These are projects that are “ready to go, need to happen, and will be finished in the fixed timetable,” the mayor said.

The city will begin replacing all of the lighting fixtures at a Staten Island elementary school on Wednesday, after toxic PCBs leaked from an overhead light onto a child’s desk and clothing.

A Brooklyn public school that had leaking light fixtures will be moved to the top of the list of schools with PCB problems, and the city will replace its lighting very soon, city officials said last week. But some health and environmental experts say the timeline for light fixture removal from schools should be expedited citywide.

Parents at a Brooklyn elementary school are calling on the Department of Education to move faster to remove toxic PCBs from lighting fixtures in school buildings around the city.

New York is one of 19 states to receive a federal waiver from complying with provisions of the No Child Left Behind law. State Education Commissioner John B. King says the waiver allows New York to disregard requirements that were “unproductive or unrealistic.”