A regional director for the U.S. National Labor Relations Board has issued a decision ordering a re-run of a union election at an Amazon.com Inc facility in Alabama, a spokeswoman for the NLRB said on Monday.

Workers at the warehouse in Bessemer, Alabama, rejected forming a union by a more than 2-to-1 margin in April. But in August, an NLRB hearing officer said the company's conduct around the previous vote interfered with the Bessemer union election.

“Today’s decision confirms what we were saying all along – that Amazon’s intimidation and interference prevented workers from having a fair say in whether they wanted a union in their workplace," Stuart Appelbaum, president of the Retail, Wholesale and Department Store Union (RWDSU), said in a statement.

Amazon spokesperson Kelly Nantel said in a statement that the company's employees overwhelmingly voted against joining the RWDSU this year. "It’s disappointing that the NLRB has now decided that those votes shouldn’t count."