A Marathon Petroleum banner outside a refinery in El Paso, Texas, U.S., October 1, 2018.
A Marathon Petroleum banner outside a refinery in El Paso, Texas, U.S., October 1, 2018. Reuters / Julio Cesar Chavez

Oil companies led by Marathon Petroleum and the United Steelworkers (USW) agreed to a new national contract on Friday for 30,000 U.S. workers in refineries, chemical plants, and pipelines, the company and the union said.

Once the deal is ratified, workers will receive a 12% pay increase over its four-year term, said three sources familiar with the matter.

"We're pleased to have reached a mutually satisfactory four-year pattern labor agreement with the United Steelworkers," Marathon spokesman Jamal Kheiry said.

USW International President Thomas Conway said in a statement the membership played a key role.

"The industry came to the table with demands that would have undermined generations of collective bargaining progress," Conway said. "Thanks to the solidarity of the membership and the hard work of our (national oil bargaining policy) committee, we have achieved a fair agreement."

Both sides did not disclose terms of the agreement.

Negotiations between Marathon and the Steelworkers had been stalled until early this week when meetings resumed, the sources said.

Talks stopped on Jan. 31 when USW negotiators rejected a 9% increase over three years and extended the current contract. basis. The current contract will remain in effect until the new contract is ratified.

USW local unions will now combine the national agreement with agreements on site-specific issues at each refinery, chemical plant and pipeline and put the combined contracts to ratification votes.

After talks stopped on Jan. 31, the USW carried out a series of protests outside refineries across the United States, which, the sources said, pushed other companies to pressure Marathon in restarting talks and increasing the pay offer as well as moving on other issues.

One issue long sought by the USW is agreement to appoint union health and safety representatives at each facility which is included in the new contract.

The pay increases are not evenly split between the four years, the sources said.