LOS ANGELES - The Los Angeles County Board of Supervisors voted unanimously Tuesday to request a seven-year extension of a state-mandated deadline to complete the seismic retrofit of two hospital facilities, effectively agreeing to build new structures.

State legislators ordered 436 acute-care hospitals to upgrade facilities following the 1994 Northridge earthquake. The original compliance deadline of 2008 was later extended to 2013.

Hospital owners financially unable to meet the 2013 deadline can instead comply by replacing an existing building with new construction by Jan. 1, 2020.

Of the six county-operated hospitals, a new County-USC Medical Center in Boyle Heights was completed in October 2008, while a new emergency department at Olive View-UCLA Medical Center in Sylmar and a new Harbor-UCLA Medical Center near Carson are under construction and scheduled for completion in 2011.

The county agreed to convert High Desert Hospital in Lancaster to an outpatient facility, avoiding the need for an upgrade.

The two remaining county facilities, Martin Luther King Jr. Multi-Service Ambulatory Care Center in Willowbrook and the Rancho Los Amigos National Rehabilitation Center in Downey, still require upgrades.

County officials have pledged to build a new emergency department building at the Martin Luther King Jr. Multi-Service Ambulatory Care Center by 2014.

At Rancho Los Amigos, the county will consolidate and relocate services and build new outpatient buildings to reach compliance standards.