On Sunday, some Safeway employees formed picket lines to fight what they say are unfair labor practices. Strikes happened at stores in Fountain, Pueblo, Estes Park and a distribution center in Denver.

The union representing Safeway store employees in Colorado has given the required 72-hour notice that the strike is set to begin one minute before midnight on Sunday.

Another grocery worker strike is in the works after UFCW Local 7 workers at Safeway and Albertsons Companies voted overwhelmingly in favor of the action — some stores voting unanimously in favor

The union said the strikes were due to unfair labor practices and an “understaffing crisis.” The union said it has given a 72-hour notice to Safeway and Albertsons, and strikes could begin as early as Sunday morning.

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.