The National Labor Relations Board (NLRB) has ordered a new election at Amazon’s Bessemer, Alabama site, a tentative victory for organizers who had sought to unionize workers at the company’s fulfillment locations. The decision, issued by the regional director overseeing the case, builds on a previous recommendation from the hearing officer assigned to the case.

“I agree with the hearing officer’s recommendations,” Monday’s decision reads. “Accordingly, I affirm the hearing officer’s rulings, I adopt her recommendation to sustain certain objections, and I order a second election.”

The decision does not name a date for the second election, which will be set in a future filing. But Amazon can also request a review of the decision from the full NLRB board, which (if granted) could prevent the election from taking place or invalidate its results after the fact.

Reached for comment, Amazon emphasized recent improvements in pay and safety for workers in its fulfillment centers. “Our employees have always had the choice of whether or not to join a union, and they overwhelmingly chose not to join the RWDSU earlier this year,” said Amazon representative Kelly Nantel. “It’s disappointing that the NLRB has now decided that those votes shouldn’t count.”

The Retail, Wholesale and Department Store Union (RWDSU), which organized the drive that culminated in the February election, hailed the decision as a victory. “Today’s decision confirms what we were saying all along,” said RWDSU president Stuart Appelbaum, “that Amazon’s intimidation and interference prevented workers from having a fair say in whether they wanted a union in their workplace.”

Announced in April, the election result delivered an overwhelming defeat for the RWDSU, with workers voting 1,798 to 738 against unionization. But that result was contested by RWDSU officials, who argue Amazon interfered with the election by — among other things — installing its own mailbox to collect ballots. Amazon security guards had access to the mailbox, giving some workers the impression that Amazon controlled the results.

In the months since, a number of other unions have expressed interest in organizing Amazon workers, and a second election at the site might face significantly more interest from other labor groups. On June 24th, the Teamsters announced a nationwide campaign to organize Amazon’s sprawling workforce. The Teamsters have committed to spending “all resources necessary” to make the campaign successful.

Zoe Schiffer also contributed to this report.

Update 4:54PM ET: Included statement from Amazon.

Update 5:25PM ET: Updated with more information about specific outcomes of the NLRB review process.