Employees at an Amazon plant in Alabama will have another chance to become the e-commerce giant’s first warehouse workers to unionize.

Dates have been set for a resumption of the controversial battle for a union in the establishment of Bessemer, a south-western suburb of Birmingham in the state’s most populous Jefferson County. Mail-in ballots will be sent to employees on February 4 and the count will begin on March 28.

The result of the previous ballot, comfortably won by Amazon, 1,798 votes to 738, was rejected on the grounds of criminal act. Amazon was found by the National Labor Relations Board to have acted illegally when it installed a mailbox outside the establishment’s entrance, a move that risked influencing workers’ decisions.

For the replay, Amazon requested an in-person vote on site. The wholesale and department store union instead suggested an in-person vote at a nearby civic center. However, citing concerns related to Covid-19, the NLRB said the vote would again be taken by mail.

The NLRB ordered that the disputed mailbox be moved to a “neutral” section of the Amazon facility.

“No party shall erect an awning, tent, banner, sign or any other object on, on, around or in sight of the mailbox,” wrote Lisa Henderson, regional director of the NLRB. “Neither party should issue any directive, suggestion or other statement to voters regarding the use of the mailbox for the purposes of this election. “

The RWDSU said the NLRB’s advice did not fully address its concerns about tampering. “We are deeply concerned that the decision does not adequately prevent Amazon from continuing its reprehensible behavior in a new election,” he said.

The union needs a simple majority of the votes returned to create the first syndicated Amazon facility in the United States.

“Our employees have always had the choice of whether or not to join a union, and they overwhelmingly chose not to join the RWDSU last year. We look forward to our team at BHM1 making their voices heard again, ”an Amazon spokesperson said in an emailed statement to the FT.

This article has been updated to include a comment from Amazon