The move is a major blow to Amazon, which had spent about a year aggressively campaigning for warehouse workers in Bessemer to reject the union, which they ultimately did by a wide margin.

It also comes at a time of widespread labor unrest in the US as a somewhat rejuvenated American union movement is flexing its muscles in an economy that is seeking to recover from the coronavirus pandemic.

The rare move was first announced on Monday by the Retail, Wholesale and Department Store Union (RWDSU), which spearheaded the union organizing movement. A National Labor Relations Board (NLRB) spokeswoman confirmed the decision.

The RWDSU charged Amazon with illegal misconduct during the first vote. In August, the hearing officer at NLRB who presided over the case determined that Amazon violated labor law and recommended that the regional director set aside the results and direct another election.