The tentative agreement, brokered in September with help from the Biden administration, had averted a strike before the midterm elections.

Workers said they were protesting the company’s refusal to bargain in good faith and other anti-union activity.

The loss raises questions about whether a national wave of unionization may be slowing. A union had won two previous votes at the grocery chain.

The company moved to contain the labor push after it took off nationally. Now, with strikes and other tactics, organizers seek to regain momentum.

Workers said pay and benefits were good, but complained that managers’ practices often seemed arbitrary.