A section of the suspended ceiling in the Reference Room installed in 1947 fell overnight on January 19, 1983, exposing the decoration that it had covered. Inspection of the collapsed ceiling revealed a weak spot that evidently caused the collapse; no signs of faulty construction of the ceiling were evident. The cost to repair the damage was approximately $50,000, and the incident prompted thorough inspections of ceilings installed in a basement area and in the card catalog area that were installed at approximately the same time.