(a) Except as provided below, an ALJ must not communicate, directly or through a representative, with any person in connection with any issue that relates in any way to the merits of the proceeding without providing notice and an opportunity for all parties to participate.

(b) An ALJ may consult on questions of law or procedure with supervisors and other staff of the Office of Hearings and Mediation Services, provided that the supervisors or staff have not been engaged in investigative or prosecutorial functions in connection with the adjudicatory proceeding under consideration or a factually related adjudicatory proceeding.

(c) An ALJ, the Chief ALJ and the deputy commissioner for hearings and mediation services may communicate with any person on ministerial matters, such as scheduling or the location of a hearing.

(d) Parties or their representatives must not communicate with the ALJ, Chief ALJ, deputy commissioner for hearings and mediation services or the commissioner, or any person advising or consulting with any of them, in connection with any issue without providing proper notice to all the other parties.