Large crack reportedly forms in window of San Francisco's sinking Millennium Tower

Officials with the City and County of San Francisco Department of Building Inspection are requiring Millennium Tower building engineers to evaluate the extent of repairs needed to fix the crack and investigate the condition of the glass panel and adjacent curtain wall system by Friday, Sept. 7, 2018. less Officials with the City and County of San Francisco Department of Building Inspection are requiring Millennium Tower building engineers to evaluate the extent of repairs needed to fix the crack and investigate ... more Photo: Courtesy Of City And County Of San Francisco Department Of Building Inspection Photo: Courtesy Of City And County Of San Francisco Department Of Building Inspection Image 1 of / 13 Caption Close Large crack reportedly forms in window of San Francisco's sinking Millennium Tower 1 / 13 Back to Gallery

A new defect in San Francisco's sinking and tilting Millennium Tower has appeared.

A large crack reportedly formed in a window on the 36th Floor of the building on Sunday, according to a resident.

Department of Building Inspection spokesperson Bill Strawn says a correction notice was issued and building engineers have 72 hours to report back on what happened.

"Our building inspector to the site...was not able to gain access to the unit and thus unable to see the alleged crack," Strawn said in an email. "The visit by the inspector was in response to a complaint."

ALSO: New '60 Minutes' shows shocking footage of the cracks in the Millennium Tower basement

NBC Bay Area reports Millennium Tower residents heard a "creaking sound and then a large pop" before the crack appeared at 2:30 a.m. Sunday.

Supervisor Aaron Peskin confirms there's a crack in a window and says, "Building management sent an email to all the owners saying they thought this crack [was related to] the ongoing problems with the building—i.e., the settling, sinking of the building."

Peskin says the window system that's part of something called the "curtain wall" is designed to sustain hurricane force winds.

"If a window failed entirely it would rain shards of glass hundreds of feet below down onto one of the busiest, most congested parts of the city. The city better take this seriously," Peskin continued

Peskin says he asked the Building Inspection Department to consider closing the sidewalks below the cracked window.

MORE, Millennium Tower keeps on sinking, but there may be a fix

Rising 645 feet, the Millennium Tower at 301 Mission St. in the South of Market district became the tallest residential building in the city when it opened in 2009.

Residents learned in 2016 that the 58-story building was sinking, and a flurry of lawsuits from owners of condos followed, including one from the homeowners association seeking $200 million.

Residents paid anywhere from $1.6 million to $10 million for their units.

The building has sunk some 17 inches since construction began in 2005 and its tilting about 14 inches.

SFGATE reached out to Millennium Tower management and didn't hear back before publishing the story.

This story was updated on Sept. 6, 2018, at 8:40 a.m.