Damaged asbestos discovered within the shared campus of Benjamin Franklin High School and Science Leadership Academy will shut down the building for at least two days, officials said Monday night.

In an email to staff and families, Danielle Floyd, the Philadelphia School District’s chief operating officer, said damaged asbestos was found both in the schools’ unoccupied boiler room and in SLA’s commons area, which remains under construction.

Tests revealed airborne asbestos fibers in both areas.

“With the safety of our students and staff as the highest priority, the building will be closed on Tuesday, Oct. 1, and Wednesday, Oct. 2,” Floyd wrote.

During the shutdown, asbestos abatement will begin on the damaged areas in the SLA commons; construction on this area has stopped. The boiler room asbestos abatement project will wait until the occupied area is fixed.

While the schools, which together educate about 1,000 students, are closed, further testing will be completed by the district and the Philadelphia Federation of Teachers (PFT) to “rule out the presence of airborne asbestos fibers in other areas of the building,” Floyd said.

Jerry Jordan, PFT president, said in a statement that the asbestos levels in those two areas “make it too dangerous to allow students, staff, and the school community to enter the building at this time.”

The Ben Franklin/SLA construction project has been plagued with problems. Before the damaged asbestos was discovered, the start of the school year was pushed back twice due to construction delays on the project, whose price tag is at least $37 million. At one point, construction was halted because of student and staff health concerns.

This is the first year that Ben Franklin and SLA have shared space; the magnet school occupied rental space prior to September.

Damaged asbestos was first discovered inside the building last week during a walk-through with School District and teachers’ union officials.

During a visual inspection, Brian Joseph, the district’s environmental director, and Jerry Roseman, the PFT Health and Welfare Fund’s director of environmental science, discovered damaged asbestos-containing pipe insulation on ductwork in the boiler room.

The district then agreed to bring in an asbestos crew to begin the process of cleaning, patching, and repairing the insulation.

While that work was underway, the district and Roseman each took 10 air samples on Saturday. Of the 20 samples, half came back with “very high levels of asbestos” fibers, Roseman said.

Asbestos is not generally a health hazard when kept in good condition and intact. But when the tiny, sharp fibers — invisible to the eye — break off, they can drift in the air for hours and are dangerous when inhaled.

The SLA commons damage was discovered soon after. Those results came back within acceptable city Public Health Department regulations for occupancy. However, a few samples did reveal the presence of asbestos fibers, Roseman said.

Because that first-floor area is under construction, Roseman said, the floor was covered in dust and debris on Sunday.

“Because of the nature of work that’s occurred there, and because of the fact that there is asbestos material present that was damaged and exposed, I concluded that those floor spaces were likely contaminated with asbestos,” he said, adding that he worried about workers tracking fibers through other work spaces.

Roseman said the project at the Ben Franklin/SLA campus has been problematic from the start, and the discovery of damaged asbestos in two areas after construction work had already begun was “a real concern.”

“Obviously, the asbestos materials that were damaged and in the way of the contractors prior to Thursday was missed, and it’s important that we don’t miss anything else, and it’s important that we really err on the side of caution,” Roseman said.

The Ben Franklin/SLA news comes at a time of heightened concern over asbestos in Philadelphia school buildings. A longtime teacher at Meredith Elementary has been diagnosed with mesothelioma, an asbestos-linked cancer.

Lawmakers and PFT leaders said that it would take $100 million to fix all the lead and asbestos problems in Philadelphia schools.

Any school built before 1980 likely contains asbestos material. Once prized for its heat resistance, the fibrous mineral was woven into pipe insulation, ceilings materials, and floor tiles.

An Inquirer investigation last year, “Toxic City: Sick Schools,” revealed that more than 80% of district buildings had some amount of damaged asbestos, including in many areas frequented by students.