The National Labor Relations Board was not required to retroactively apply a new standard to a pending dispute over an arbitral decision, a federal appeals court ruled Tuesday in turning down an employee’s challenge to her termination.

The U.S. Court of Appeals for the Ninth Circuit supported the NLRB’s prospective application of a new, less deferential standard for determining when the panel should accept an arbitration decision. The employee, a forklift operator named Coletta Beneli, argued the new standard should apply in her case.

Beneli was fired from Babcock & Wilcox Construction Co. Inc. two months after she was hired. A grievance review committee, through binding arbitration, upheld her termination.

The federal labor board’s usual practice is to apply new policies and standards in all pending cases, at whatever stage, the Ninth Circuit said. In Beneli’s case, the NLRB adopted a new standard for arbitral agreements but Beneli’s complaint was analyzed under the older, more deferential standard. The board ultimately deferred to the arbitral decision, and Beneli lost her challenge to her firing.

The appeals court, executing a balancing test, concluded it was lawful for the NLRB’s new policy—which is less deferential to arbitral decisions—to apply only prospectively. The old standard had been in place for nearly 60 years.

“Courts of appeals throughout the country, including this one, repeatedly upheld that standard. Thus, the new standard represents an abrupt departure from well-established practice,” the Ninth Circuit said Tuesday.

The new standard shifts the burden of proof and makes deferral to an arbitral decision less likely, the appeals court said. This view was applied only to future cases, but not in Beneli’s case, because of its potential impact on “settled expectations of employers and unions, who had bargained for dispute resolution mechanisms under the old NLRB standard,” the appeals court said.