In April 2005, a glass panel, two thirds up the tower, fell to the plaza beneath. The plaza was sealed off, but the building remained open. A temporary covered walkway, extending across the plaza to the building's reception, was erected to protect visitors. Engineers examined the other 744 glass panels on the building. The cost of repair was covered by main contractor Skanska and curtain-wall supplier Schmidlin (now called Schmidlin-TSK AG). The open-floor ventilation system did not operate as designed due to tenants adding glass partitions to increase security.