A teacher at Benjamin Cardozo High School captured video of the building now crawling with mice and cockroaches.
And because of windows that won't fully open, they say there's poor ventilation.
"Teachers vote! Stay remote! Teachers vote! Stay remote!" they could be heard yelling at a rally.
Video Thursday morning showed teachers rallying outside Benjamin Cardozo High School:
Teachers at the high school have given the mayor an F for the city's school reopening plan.
Cleaning teams were supposed to sanitize schools over the summer, but the even bigger problem is they say they're so short on teachers that 65 classes right now do not have one.
Some kids logged onto online orientation Wednesday with no teacher on the other side.
"We have six to seven teachers in one room trying to conduct remote classes at the same time, so the noise level, the volume, you hear every other teacher talking, you hear the kids responding on every computer," teacher Dino Sferrazza said.
Meanwhile, at a march in Lower Manhattan, actress Cynthia Nixon joined educators who also had fighting words for city hall.
"The mayor should be ashamed of himself. It is shocking that this morning the mayor changed the plan at the start of the school year again just a few days before students were expected," said Councilwoman Carlina Rivera
The latest plan includes a phased reopening. For older students, in-person learning was delayed again --this time by more than a week.
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The mayor says he's working together with school employee unions who say in-person learning is still the goal.
"Yesterday morning they reached out to me and said they had real concerns about specific things that had to be done," Mayor Bill de Blasio said.
"We are not going to be a school system that puts a camera in the middle of a classroom where you see a teacher every once in a while in front of a camera," said UFT President Michael Mulgrew.
"To me that was the big red flag. If we have students entering into a building without a teacher, that is simply not going to work," said CSA President Mark Cannizzaro
The chair of the City Council's education committee meanwhile blasted the mayor too, saying educators once again were caught off guard by Thursday's decision to delay.
"This stubbornness and this inability to come face to face with reality, it's very costly in a cross. Quite frankly, it's also Trumpian," Councilman Mark Treyger said.
The mayor says by day one Monday the city will add more teachers -- some from the substitute pool, some current DOE staff and some from the CUNY system, about 4,500 more educators.
But the principals' union says they need at least twice as many, or 10,000 more. The Independent Budget Office says the system needs nearly 12,000 more.
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