The National Labor Relations Board (NLRB) has determined that Amazon retaliated against two activist employees when it fired them in April of last year, as first reported by The New York Times.

The determination is part of the board’s ongoing response to a labor complaint against Amazon, although it’s not a legal ruling in itself. Still, the determination indicates the NLRB is prepared to accuse Amazon of unfair labor practices in connection with the case, and that puts the company under significant pressure to settle the case with the fired employees.

The two employees at the heart of the case, Emily Cunningham and Maren Costa, organized the Amazon Employees for Climate Justice group in 2020 to protest the company’s partnerships with the oil and gas industry. The group went public with an open letter that January, undersigned by more than 350 employees.

Amazon fired Cunningham and Costa three months later, after they used the same Medium account to raise concerns about coronavirus protections at Amazon warehouses. It is unclear how the case will be resolved, but both women are being encouraged to settle with the company by the NLRB.

Reached for comment, Amazon disputed the determination. “We disagree with these preliminary findings,” a representative said. “We terminated these employees not for the reasons cited in the preliminary finding, but because they repeatedly violated internal policies.”

At the same time, the employee group founded by the two women applauded the ruling. “Amazon tries to stoke fear in employees that speaking out is wrong,” a representative from Amazon Employees for Climate Justice said. “But the NLRB’s ruling confirms that it is legally right for us to speak out as employees, just as we know we are in the moral right to protect our own climate future.”

The new determination is part of a growing pattern of labor violations at Amazon, which has been accused of violating workers’ rights to protest labor conditions in a growing number of cases. In March, the NLRB made a similar determination about retaliation against organizers at a warehouse in Queens, as well as a separate retaliation case connected to a warehouse in Chicago. Six Pennsylvania warehouse workers are also pursuing a retaliation case against the company in federal court. An NBC News analysis counted 37 separate labor rights cases against Amazon filed with the NLRB since February 2020.

Amazon has exacerbated the issue by publicly feuding with a number of prominent progressive lawmakers, including Sens. Bernie Sanders (I-VT) and Elizabeth Warren (D-MA). On Friday, the company publicly apologized for a series of tweets denying that Amazon drivers are sometimes forced to pee in bottles, a phenomenon subsequently confirmed by multiple Motherboard reports.

“This was an own-goal,” Amazon said in its apology. “We know that drivers can and do have trouble finding restrooms because of traffic or sometimes rural routes.”

Update 8:54AM ET: Included statements from Amazon’s corporate representative and Amazon Employees for Climate Justice.