A huge piece of sheet metal dangling from the side of a San Francisco hotel brought rush-hour traffic to a stop in the area, as crews worked to remove the hazard before it fell the the busy street below.

NBC Bay Area reports that the loose piece of metal was spotted hanging from the Hilton San Francisco Union Square Hotel, which is located at 333 Taylor Street, at 6 p.m. Thursday.

Police swiftly closed the streets and sidewalks in the area, the Chron reports, blocking off Taylor Street between O'Farrell and Ellis Streets, as well as the stretch of Jones Street near the hotel.

According to NBC, the metal was "a piece of loose siding on the 18th floor of the hotel's Tower 2." CBS 5 reported at the time that the siding was "basically only attached at one corner and can be seen moving in the wind."

It wasn't until 8 p.m. that the loose piece was removed, after "a worker went up in a window washing lift and pulled it down," NBC reports.

It's still unclear why the siding was loose in the first place. In a statement sent to media, the Hilton says that "the hotel is cooperating fully with local authorities to determine the cause of the incident."