PASADENA, Calif. (AP) — The city of Pasadena’s historic Central Library has been ordered closed pending further review due to seismic safety concerns.

The city says the nearly century-old Mediterranean Revival-style building had just reopened for in-person services following a pandemic closure when the closure order was issued Monday.

A recent structural assessment revealed that most of the building is constructed with unreinforced masonry bearing walls that support concrete floors and walls.

So-called URM buildings are known to be at risk of collapse in an earthquake.

A 1993 order requires URM buildings to be retrofitted, vacated or demolished, but the city can't find any record of why the library was not identified.