A sinking and tilting skyscraper in San Francisco is now at risk of a major cladding fire, according to a report.

The investigation looked at the safety of the 58-storey Millennium Tower, which in March of this year was found to have sunk 17 inches (43 centimetres) and tilted 14 inches (36 centimetres) since completion in 2008.

It found that the movement had dislodged the curtain wall away from the main structure, leaving a gap where smoke and fire could quickly spread.

Engineering company Allana Buick & Bers, who conducted the enquiry, drew the conclusions after looking at two areas of the building's facade. But the company suggested that the same was likely to be found across the entire structure, endangering the lives of its residents.

"These openings represent a breach in the fire and smoke safety barrier, which is a life and safety hazard to the occupants," it said.

Investigation prompts further action

Allana Buick & Bers was commissioned to produce the report by the homeowner's association, on behalf of the tower's occupants.

Its findings were picked up by San Francisco news channel NBC Bay Area and – in light of the fatal recent fire at Grenfell Tower in London – have triggered alarm.

The local fire department is reportedly looking into the situation further, while San Francisco supervisor Aaron Peskin has ordered the city's Department of Building Inspection to verify the independent report.

"The whole thing is just really disturbing and troubling," he told NBC Bay Area.

"Not only do all the condo owners have the right to have that information," he continued. "But the city should have that information, so we can impose the kind of fixes that have to be imposed."

Report commissioned after resident noticed smell

Designed by Handel Architects, the Millennium Tower is currently the tallest residential building in San Francisco, and the city's third tallest overall.

Allana Buick & Bers' investigation of the luxury condominium tower was instigated by resident Paula Pretlow, who noticed a strange odour in her home. The spread of the smell is now believed to have travelled through the gap in the facade.

Speaking to NBC Bay Area, Pretlow initially received the report in December 2016, but the safety warning was blacked out. She said she has spent the past year since sourcing the missing details.

Pretlow is among many unhappy condo owners currently residing in the high-rise. Upon its completion it boasted some of the city's most expensive apartments, but these have fallen significantly in price, as a result of the sinking.

Tower found to be sinking earlier this year

This sinking was discovered through analysis produced by Arup. Its latest research, published in July 2017, stated that the building had descended two inches (five centimetres) in just six months.

Millennium Partners, the property company behind the building, responded to the news by employing engineers to come up with a solution to stop further dropping, and also a way to prop the building back up again.

At the time, the developers claimed that the building was still safe to live in, despite its excessive settlement.

Dezeen contacted Millennium Partners for comment but is yet to receive a response. But the company has recently taken up the issue of wall problems with Texas-based cladding consultant behind the building Curtainwall Design Consulting – it filed a lawsuit against the firm last month.