In the newest complaint accusing the coffee chain of using improper labor practices, a U.S. labor agency is attempting to compel Starbucks Corp (SBUX.O) to reopen 23 outlets that were purportedly closed last year in order to thwart a national union push.

Eight of the U.S. stores had already become unionized when they closed, according to a complaint filed on Wednesday by a regional director of the National Labor Relations Board (NLRB).

Since 2021, employees at over 360 of Starbucks’ 9,300 U.S. locations have cast ballots to form unions, and the business is currently dealing with over 100 NLRB charges that accuse it of engaging in various illegal union-busting practices.

Starbucks has denied wrongdoing and said it respects workers’ rights to choose whether to unionize.

The company did not immediately respond to a request for comment on Thursday.

The case will be heard by an administrative judge, whose decision can be appealed to the five-member NLRB and then to a federal appeals court.