No one was injured when glass fell from the 17th floor a 24-story Financial District high-rise Wednesday afternoon to a 6th floor balcony below, San Francisco officials said.

The original incident occurred at 11:30 a.m., said San Francisco fire Lt. Mariano Elias. Fire crews arrived at 1:40 p.m., he said, after building officials summoned the fire department after finding a piece of loose glass on the 17th floor. He said fire crews arrived and secured the street below.

A spokesman for the building, 150 California Street, said “our primary concern is for the people involved with this incident” and added that its managers were working with the authorities conducting the investigation.

The cause is not known, said Patrick Hannan, a spokesman for the Department of Building Inspection.  He noted the glass that broke was the outside pane of a double paned window, and the interior pane was not broken.

“There may be some modest damage to some of the other windows and the patio,” he said. “Fortunately, nobody was injured.”

He noted that a building inspector working nearby at the time of the incident. The department issued a notice of violation was issued requiring that the window be replaced, inspected and that other buildings be checked for damage, Hannan said.