Union workers at Marathon Petroleum’s Martinez Renewables facility went on strike Monday amid negotiations for a new labor agreement, according to the company.

The strike by hourly employees represented by United Steelworkers Local 5 comes after four months of collective bargaining that has not resulted in a new agreement after the previous labor agreement between the refinery and union expired on Jan. 31, Marathon spokesperson Jamal Kheiry said.

Kheiry said refinery operations normally handled by the union workers have been turned over to “trained and qualified Marathon employees.”

United Steelworkers Director Gaylan Prescott, who represents the union’s District 12 that includes members in California and other Western states, alleged in a statement that “members are striking in protest of the employer’s unlawful conduct” during the last four months of negotiations.

“We urge Marathon to return to the table and to abandon its ill-advised illegal bargaining strategy so that the company’s highly trained, union-represented workforce can return to their jobs with justice and dignity,” Prescott said.

Marathon announced in late 2020 plans to convert the Martinez refinery to one that processes renewable feedstocks like soybean and corn oil rather than crude oil from fossil fuels.

Dan McMenamin is the managing editor at Bay City News, directing daily news coverage of the 12-county greater Bay Area. He has worked for BCN since 2008 and has been managing editor since 2014 after previously serving as BCN’s San Francisco bureau reporter. A UC Davis graduate, he came to BCN after working for a newspaper and nonprofit in the Davis area. He handles staffing, including coaching of our interns, day-to-day coverage decisions and management of the newswire.