The NLRB's new order says the decision by an acting regional director “raises substantial issues warranting review.”

The regional official ruled against the smaller bloc vote after finding the few dozen workers share an “overwhelming community of interest” with the rest of the facility’s production and maintenance workers, and that the only appropriate unionized group through the International Association of Machinists and Aerospace Workers campaign would be one representing about 4,300 production and maintenance workers plantwide. The union did not want the larger vote and did not pursue it.

Three Democratic NLRB members picked by President Joe Biden voted to review that ruling. Two Republican members selected by former President Donald Trump voted against it.

The union has argued that the 87 employees sought for a bargaining unit have extremely specialized skills for a job that others at the plant do not and are therefore be eligible for standalone representation.

Nissan has contended that the employees are not sufficiently distinct from other plant workers to be eligible for their own small unionized subgroup.

Nissan does work with organized labor in the rest of the world, but past votes to unionize broadly at the company’s U.S. two plants have not been close. Workers in Smyrna rejected representation by the United Auto Workers in 2001 and 1989. Workers at Nissan’s assembly plant in Canton, MS, rejected UAW representation in 2017.