A federal appeals court on Wednesday revived a constitutional challenge to a private-sector firm's role in conducting unclaimed property audits on behalf of Delaware.

The narrow ruling by the U.S. Court of Appeals for the Third Circuit came on an appeal by Plains All American Pipeline, which had challenged a lower court's earlier findings that broader claims against both the state and independent auditor Kelmar Associates were too speculative to support the lawsuit.

In a precedential opinion, a three-judge panel of the appeals court upheld the bulk of the dismissal, but allowed a procedural due process claim against Kelmar to continue, saying that the Boston-based firm's own financial stake in the outcome of the audits had rendered the issue ripe for review.