About 45,000 grocery workers have authorized a strike at Ralphs, Albertsons, Vons and Pavilions stores in Southern California to protest unfair labor practices.

The union will take strike authorization votes this week after filing unfair labor practice charges against the companies last week.

Safeway workers are striking at the same time as contract negotiations between workers and King Soopers are coming to a head. The union is negotiating with King Soopers and parent Kroger after a strike in February. That strike lasted almost two weeks before a deal was reached to pause the labor action for 100 days. That pause expired last month.

With the clock winding down toward Saturday night's deadline for new contract negotiations, a Colorado union has announced locations where grocery employees are set to walk off the job on Sunday in protest.

Currently, unfair labor practice strikes are limited to Safeway/Albertsons locations in just four cities: stores in Estes Park, Fountain and Pueblo, and a distribution center in Denver.

Now, another supermarket chain is about to join this alarming trend. Safeway and Albertsons workers reject the latest offer, intend to strike The United Food and Commercial Workers Local 7 rejected the latest offer from Safety and Albertsons (ACI) and delivered 72-hour notice that its employees plan to terminate their current contract extension and go on strike.

UFCW Local 324 negotiations with Albertsons and Kroger’s trigger unfair labor practice claims and a potential strike.

The union that represents 7,000 Safeway/Albertsons employees in Colorado terminated its contract extension with the company on Wednesday.