Pacific Alliance Medical Center, the oldest hospital in Los Angeles, with roots predating the Civil War, will close in December, laying off 640 workers.

The 157-year-old Chinatown hospital, citing the massive cost of a required seismic retrofit, said it would close when its lease expires Dec. 11.

“PAMC does not own the land on which our hospital sits and the owner is unwilling to sell the land to us,” the hospital announced in a statement. “The hospital building does not meet current California seismic standards and it is not economically viable for us to invest nearly $100 million to build a hospital on land that we would not own.”

The center located at both 531 and 711 W. College St. and North Hill Street will lay off 640 workers, according to a state Worker Adjustment and Retraining Notification issued last week.

The announcement to close the 128-bed acute care hospital comes four months after Pacific Alliance agreed to pay $42 million in penalties after a federal whistleblower lawsuit that claimed it filed false medical claims in a kickback scheme.

The medical center opened in 1860 as French Hospital to serve a settlement of French immigrants. A landmark Joan of Arc statue still stands on its front lawn.

The hospital nearly closed in 1989, but was rescued by a physicians group and members of the Chinese community.

Pacific Alliance MC Ltd. is listed as the current property owner of the 66,000 square-foot facility built in 1981, according to real estate records.

The hospital statement said it would work hard to avoid any disruption of patient care.

“PAMC will remain appropriately staffed until it closes,” it said. “We will assist any inpatients and their physicians in transitioning their care to another area hospital prior to closing. We did not take this decision lightly, and we are committed to doing everything we can to ease the transition for affected employees. We will work with other local hospitals to help find employment opportunities for our impacted staff.”

The company reported nearly $17 million in operating losses through the first half of the year, according to a state report.

Health business reporter Dana Bartholomew can be reached at [email protected]. Follow him on Twitter @_DanaBart.