Concerns over widespread damaged asbestos have closed another Philadelphia school.

Hopkinson Elementary, a crowded Juniata K-8 that educates 850 students, will be closed at least Monday and Tuesday while air testing is completed in the building. It is the seventh school to close in the 2019-20 term.

Crews had been working at Hopkinson, on L Street, addressing “imminent hazards” in multiple locations across the school, including the cafeteria. The school remained open, with key locations sealed off and workers completing remediation when children and staff were not in the building.

But the situation escalated Friday, when officials of the Philadelphia Federation of Teachers union shared with Hopkinson staff the extent of the damage at the school. During an earlier district walk-through, environmental staff had observed roughly 55 locations of damaged asbestos. Much of it was above ceiling tiles, with visible debris sitting on top of the tile.

Then one teacher shared with PFT staff that over the summer, the district had replaced all the ceiling tiles — and had not used abatement protocols, despite the widespread prevalence of asbestos. Dust was everywhere, the teacher said, and nearly every classroom was affected.

“That situation cannot be considered safe,” said Jerry Roseman, the PFT’s director of environmental health and safety. “The degree of danger may be unclear. We don’t know how much danger there is, but we know it’s not safe.”

The district agreed to the closure on Sunday night.

Jerry Jordan, PFT president, said in a statement that “no one should ever have to be forced to occupy a building that can quite literally poison them. It is unclear to us when the building will be safe for reoccupancy.”

Jordan called the tile replacement job “potentially severe asbestos exposure” and said it would require more than air sampling for the PFT to agree to a reopening. He exhorted the district to “adequately plan, as well as notify the community throughout this process.”

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As the district grapples with an unfolding asbestos crisis, it has struggled to keep school staffs and communities informed about the environmental hazards in their midst, earning widespread scorn for its missteps.

Even as the school board expressed confidence in Superintendent William R. Hite Jr. last week, it took district officials to task.

“There are almost daily indicators that the system as we know it is flawed,” board member Mallory Fix Lopez said. “It’s not OK that the community is simply left to trust the process."

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The PFT is suing the district over its handling of the asbestos crisis.