Tesoro workers in Los Angeles represented by the United Steel Workers union have voted to authorize a strike if the bargaining committee and refinery management cannot agree on a new contract.

With its vote the unit has joined workers at Tesoro refineries in Martinez, Calif., Anacortes, Wash., and Mandan, N. Dakota in authorizing a strike.

Hawaii workers earlier reached an agreement with management.

The Tesoro Hawaii refinery and the company’s 32 gas stations are for sale. The company has considered the facility underperforming in the last few years . Fourth quarter earnings for last year showed that operations at Hawaii’s largest oil refinery contributed to a $124 million loss for Tesoro Corp., though the company’s full-year profit was $546 million.