Philadelphia’s McClure and Carnell Elementary Schools won’t reopen this week, after the discovery of damaged asbestos led the district to close the buildings before the holiday break.

District officials on Tuesday announced that the buildings, closed since Dec. 20, would remain shut Thursday and Friday out of an “abundance of caution.” The schools, which together educate roughly 1,600 students, are the fifth and sixth closed by the district due to asbestos concerns this school year.

When they will reopen isn’t clear. Imahni Moise, a spokesperson for the district, said Tuesday that while “imminent hazard” asbestos issues had been addressed at Carnell, in Oxford Circle, “there is still concern for some additional areas, the need for more aggressive follow-up cleaning, and also another round of testing before the school can reopen."

At McClure, in Hunting Park, “asbestos still needs to be removed from pipe risers on three floors and the building must be cleaned and tested before it can reopen,” Moise said in an email. The district will be posting air-quality testing results on its website.

Moise said the district had not identified a date for either school to reopen. McClure enrolled about 700 students last year; Carnell had more than 900.

The district and its aging buildings have been plagued by asbestos issues. Benjamin Franklin High and Science Leadership Academy were closed for weeks after damaged asbestos was discovered in the renovated Ben Franklin building the two schools were to share, followed by the removal of students from T.M. Peirce Elementary. In mid-December, Franklin Learning Center was closed, days before the district announced it would also shut McClure and Carnell.

While asbestos in good condition is not considered a health risk, damaged asbestos can release microscopic fibers that can cause cancer when inhaled.

Staff at both elementary schools are still expected to work Thursday: Those from McClure should report to Roberto Clemente Middle School, 122 W. Erie Ave., and those from Carnell to the Little School House on the elementary school’s grounds, officials said.