Kellogg Brown & Root Services Inc. doesn’t have to disclose certain documents to a whistleblower, a federal appeals court ruled on Friday in a dispute that raised concern among companies about the confidentiality of communications with in-house lawyers.

The U.S. Court of Appeals for the D.C. Circuit overturned a trial judge’s decision to force KBR to turn over 89 documents that the company argued were shielded by the attorney-client privilege. Lawyers for whistleblower Harry Barko, who brought a False Claims Act suit against the company, sought access to the information. The papers are about KBR’s investigation into whether the company and a subcontractor, Daoud & Partners Inc., maintained an inappropriate relationship that involved kickbacks. Daoud built and staffed laundry facilities in Iraq for the U.S. Military.