By CBS3 Staff

ALLENTOWN, Pa. (CBS) – A three-alarm blaze badly damaged the Sacred Heart School in Allentown. The fire burned for hours at the pre-K through 8th-grade school located on North Fourth Street.

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At one point, a firefighter fell through the floor but was able to get out using a ladder. No word on that firefighter’s condition.

The building has stood since 1925.

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The cause of the fire remains under investigation.