The union representing about 20,000 grocery workers in Oregon and southwest Washington has taken one step closer to a strike.

That doesn’t mean a strike is inevitable or that it would involve all workers.

The latest move occurred Thursday, a day of contract negotiations between United Food and Commercial Workers Local 555 and some of the region’s biggest supermarkets, including Fred Meyer, Albertsons and Safeway. The two sides continued to clash over the size of wage increases that will roll into dozens of contracts for different regions, stores and departments.

UFCW Local 555 gave Fred Meyer 10 days’ notice that it plans to cancel what’s known as the CCK — or “central checkout” — contract. That agreement covers a group of about 2,300 Fred Meyer cashiers.

Canceling the contract opens the door to other economic actions — a door the union appears ready to walk through.

“There is a high likelihood that we will see an economic action taken against stores in the near future,” UFCW Local 555 president Dan Clay said in a statement. “We will release details by Tuesday, September 10th.”

The union wouldn’t comment on what form those actions might take, but leafleting and picketing are common options. A strike would be the ultimate move, even if it’s limited to one department.

Fred Meyer posted a statement saying it, “must prepare for any potential disruption to our business, including a strike.” To that end, the company said, it will advertise and hold job fairs for temporary workers, though it hopes not to use them.

Albertsons Cos., which operates Albertsons and Safeway, has remained relatively quiet during contract negotiations. Fred Meyer, however, has been unusually public about posting the framework of its bargaining position. The company said it has offered bigger wage increases, in absolute terms, than were approved in the last two contracts. According to an updated initial offer on its website, those increases ranged from 30 to 40 cents an hour for the most experienced employees.

Kelley McAllister, communications director for UFCW Local 555, called the wage offer “appalling” and said it did too little to bridge what the union sees as a gender pay gap exacerbated by a two-tier wage system.

“It didn’t feel as if they were even attempting to reach an agreement,” she said about the group of employers.

The union wants a federal mediator to join future negotiations.

UFCW Local 555 has also criticized Fred Meyer’s plans for the health and welfare fund used to pay employee health benefits. The company says the trust fund is overfunded and holds 20 months of reserves. It has proposed temporarily reducing company payments into the fund while maintaining six months of reserves. It said that wouldn’t require a reduction in employee benefits or an increase in employee contributions.

Heading into Thursday’s talks, McAllister said the union considered a six-month reserve to be adequate, but that any excess money should go directly into members’ pockets.