Mold remediation at East Pennsboro Area High School in Enola, Pa., is forcing middle and high school students to share classrooms for about three weeks.

The Harrisburg Patriot-News reports that the East Pennsboro district has decided to have high and middle school students operate on split schedules at the middle school while the high school building undergoes mold remediation. Beginning Wednesday, high school students will attend classes in the morning, and middle school students will attend classes in the afternoon.

All four district schools were closed last week because of elevated mold levels. The district's two elementary schools—East Pennsboro and West Creek Hills—reopened today after they were cleaned and retests showed no elevated levels of mold. The district delayed the return of middle and high school students by a day so that faculty and staff could prepare for sharing space.

District officials say mold developed in the high school after recent humid weather caused chilled water lines for the air conditioning system to sweat. That led to mold growth on paper surrounding pipe insulation and on ceiling tiles.

The district had hoped the high school mold remediation could be completed over the weekend. But more time was needed so that pipes can be reinsulated.

Make-up days have been announced for some of the time missed by students last week.