39 C.F.R. § 956.13

Ex parte communications are not allowed between a party and the Hearing Official or the Hearing Official's staff.

(a) Ex parte communication means an oral or written communication, not on the public record, with only one party with respect to which reasonable prior notice to all parties is not given, but it will not include requests for status reports or procedural matters.

(b) A memorandum of any communication between the Hearing Official and a party will be transmitted to both parties.