Amazon is losing its attempt to overturn a historic union vote at its New York-based warehouse.

Employees at Amazon’s Staten Island location were finally handed a victory Thursday after a hearing officer for a federal labor board certified the result of their union vote.

Initially, the online retailer had contested the election results, filing 25 objections with the National Labor Relations Board. In addition, Amazon claimed the vote was improperly influenced by organizers and the agency that oversaw the election.

Some members of the Amazon Labor Union took to social media to celebrate the accomplishment.

“Today is a great day for labor,” tweeted Chris Smalls, a fired Amazon worker who now heads the union. The Amazon Staten Island workers voted 2,654 to 2,131 on April 1 to join the (ALU).

It was not a quick decision for the federal labor official who presided over the weeks-long case that started on June 13. After twenty-four days of hearings in which Amazon unsuccessfully sought to close the proceedings to the public, the federal labor official recommended Thursday that the union be certified.

Lisa Dunn, the agency officer who handled Amazon’s case, determined that the e-commerce giant’s objections should be entirely overruled and that the union should be certified as a bargaining representative for the warehouse, a spokesperson for the NLRB wrote in an email.

Amazon “has not met its burden of establishing that Region 29, the Petitioner, or any third parties have engaged in objectionable conduct affecting the results of the election,” the spokesperson said, explaining Dunn’s recommendation.

A spokesperson for Amazon said the company would continue to contest the decision to unionize.

“While we’re still reviewing the decision, we strongly disagree with the conclusion and intend to appeal,” Amazon spokesperson Kelly Nantel said in a statement. “As we showed throughout the hearing with dozens of witnesses and hundreds of pages of documents, both the NLRB and the ALU improperly influenced the outcome of the election, and we don’t believe it represents what the majority of our team wants.”

All three parties, including Amazon, the union, and the agency representing the voters, will have until September 16 to file any exceptions to the report. If any arguments are successfully made, the case will move to the regional director, who can either issue an order to certify the election or officially order a rerun vote.

Amazon will still have one final option to appeal the results based on the regional director’s decision. The last line of defense for Amazon is the five-person labor board, which is likely to be sympathetic to the union.