By Commission. (1) Whenever there is instituted before the Commission any proceeding under either the Federal Power Act or the Natural Gas Act, the State commission or commissions of the State or States affected thereby will be given notice thereof immediately by the Commission. As deemed necessary for an understanding of the subject matter, each such notice will be supplemented by copies of applications, complaints, petitions, or orders instituting proceedings. Each such notice given to a State commission will request that the Commission be notified within a reasonable time whether the proceeding is deemed one that should be considered under the cooperative provisions of this subpart, and, if so, to advise the Commission as to the nature of its interest in the matter, and further, to specify whether it desires a conference, the creation of a board, or a joint or concurrent hearing, as defined in this subpart and the reasons for such request.

Any commission suggesting some form of such cooperative procedure should also state whether there is pending, or will be pending before it, a proceeding in which a concurrent hearing might appropriately be held and whether its proposal is for such hearing covering such proceeding and the proceeding pending before the Commission.

A State commission recommending to the Commission reference of a proceeding to a board, under either the Federal Power Act or the Natural Gas Act, should state with fullness the reasons which led it to believe that such reference is desirable and in the public interest.

Upon the receipt from a State commission of a communication suggesting cooperation, the Commission will consider the same, and may confer with the commission making the request and with other interested commissions, if any, in such manner as may be most suitable, and, if cooperation in the manner proposed, or in any other manner, appears to be practicable and desirable, will so advise each interested State commission, and will invite it to participate therein.

By State commission. (1) Each State commission should, in like manner, notify the Commission of any proceeding instituted before it the subject matter of which is also subject to the jurisdiction of the Commission, or in which it believes the Commission is interested. Such notice should be supplemented by copies of applications, petitions, complaints, or orders instituting proceedings which may be necessary to an understanding of the subject matter. Such notice should include the suggestions which the State commission may wish to make concerning cooperative procedure.

Upon receipt of such notice, the Commission will consider the same and will promptly notify the State commission whether or not in its opinion cooperation in the manner proposed, or in any other manner, appears to be practicable and desirable. The Commission is free to propose cooperative procedures whether or not such proposal of cooperation has been made by the State commission first giving notice of the proceeding.

Commission or State commissions to invite participation in cooperative procedure. In the event that cooperation in a particular proceeding has been determined upon, the Commission or a State commission before which the proceeding is pending will so advise each interested State commission and will invite it to take part therein.