NEW YORK (Reuters) -Phillips 66 is expected to lay off most workers at its 139,000-barrel-per-day Los Angeles-area refinery in December, sources familiar with the matter said on Thursday.

The company announced in October it would close the facility and begin winding down operations in October 2025. The workforce reduction will begin two months later.

The Los Angeles facility has about 600 employees and 300 contractors. Over half of the employees are hourly workers represented by the United Steelworkers Union.

A few retained workers will be transferred to Phillips 66's Los Angeles marine oil terminal, the sources said. 

"Since the announcement was made to idle these facilities, Phillips 66 has stated its commitment to helping employees and contractors through this transition," a Phillips 66 spokesperson said.

The spokesperson declined to comment on plans after the closure of the Los Angeles-area refinery.

Valero Energy ( VLO ) also announced this year its decision to close the 145,000-bpd Benicia refinery, one of its two remaining refineries in the state.

The two refineries produce roughly 20% of the state's gasoline supply.