SAN FRANCISCO (AP) — A 58-story luxury apartment building in San Francisco continues to sink and is tilting about 3 inches per year.

The engineer responsible for fixing the troubled building says that without a fix the luxury building’s lean could reach a 40-inch tilt, which would be the point at which the elevators and plumbing may not continue to operate.

KNTV-TV reports the engineer told the San Francisco Board of Supervisors in an update hearing last week that the building remains safe and that installing 18 steel piles to bedrock is the best way to stop the tilting and possibly reverse some of it.