CHELSEA, Mass. – A Massachusetts high school is shut down this week over a fly infestation stemming from broken pipes below the school’s concrete foundation.

Construction workers are scrambling to cut through the thick concrete foundation at Chelsea High School to repair several pipes that cracked underneath and created conditions for the flies to flourish, WCVB reports.

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The problem started with complaints of flies in the kitchen earlier this month, and when an exterminator came out to investigate the problem only got worse. A video investigation of the pipes under the school revealed the source.

“The school is structurally supported by a foundation that is a concrete slab,” school officials wrote in a notice to parents that canceled classes for Monday and Tuesday. “These pipes sit below the concrete slab and cover 1.5 acres. By Thursday afternoon the video investigation had identified two broken pipes. By the end of the day on Friday, two additional cracked pipes had been identified for a total of four pipes.”

“Now that we have diagnosed the cause of the problem, we are turning our attention to fixing it,” Chelsea Public Schools Superintendent Mary Bourque posted to the school’s website. “Because of the structural nature of the work, our engineers have been working to develop a plan for cutting through the slab of concrete to get to the cracked pipes.”

“The timeline … depends upon the speed in which we can hire a contractor and how fast they can begin their work,” she wrote. “While this was an unanticipated issue, it is making us rethink our annual maintenance plans to include a video investigation of pipes in all our schools as part of our regular procedures.”

The notice did not stipulate what type of pipes had ruptured.

The school was closed on Thursday and Friday last week, and is expected to remain closed at least through Tuesday, and possibly longer, the Boston Globe reports.

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The high school is also closed for a December break, from Dec. 26 to Jan. 3.

Locals who commented about the situation online allege the flies are only part of the problem.

“It’s not just flies, it’s really big roaches also,” Kaitlyn Holmes posted to Facebook. “They just don’t wanna put that part on the news!”

“ … I dealt with a similar problem in Chelsea many years ago. Important fact: Much of Chelsea is built on old swampland, and there is still tidal action in the soils,” geolovely wrote in the Boston Globe comments.

“The building’s foundations, resting on deep piles, had stayed put, and the slab, fortunately, also stayed put, and it went from being a slab on grade to a floating structural slab, but this had been anticipated in the slab’s design,” geolovely posted. “It was not anticipated by the plumbing designer, and the pipes below the slab could not support their own weight and broke away. As a result, for years raw effluent was deposited below the slab. (Years of reports of odd smells were thus finally explained.)”