(a) No labor organization will be permitted to intervene in any proceeding involving a petition filed pursuant to § 1422.2 (a) or (b) unless it has submitted to the Regional Director a showing of interest of ten percent (10%) or more of the employees in the unit described in 22 U.S.C. 4112 together with an alphabetical list of names constituting such showing, or has submitted a current or recently expired agreement with the Department covering any of the employees involved, or has submitted evidence that it is currently recognized or certified exclusive representative of any of the employees involved: Provided, however, That an incumbent exclusive representative shall be deemed to be an intervenor in the proceeding unless it serves on the Regional Director a written disclaimer of any representation interest for the employees involved: Provided, further, That any such incumbent exclusive representative that declines to sign an agreement for consent election because of a disagreement on the matters contained in § 1422.7(c) as decided by the Regional Director, or fails to appear at a hearing held pursuant to § 1422.9, shall be denied its status as an intervenor.

(b) No labor organization may participate to any extent in any representation proceeding unless it has notified the Regional Director in writing, accompanied by its showing of interest as specified in paragraph (a) of this section, of its desire to intervene within twenty (20) days after the initial date of posting of the notice of petition as provided in § 1422.4(a), unless good cause is shown for extending the period. A copy of the request for intervention filed with the Regional Director, excluding the showing of interest, shall be served on all known interested parties, and a written statement of such service should be filed with the Regional Director: Provided, however, That an incumbent exclusive representative shall be deemed to be an intervenor in the proceeding in accordance with paragraph (a) of this section.

(c) Any labor organization seeking to intervene in a proceeding involving a petition for determination of eligibility for dues allotment filed pursuant to § 1422.2(d) may intervene solely on the basis it claims to be the exclusive representative of some or all the employees specified in the petition and shall submit to the Regional Director a current or recently expired agreement with the Department covering any of the employees involved, or evidence that it is the currently recognized or certified exclusive representative of any of the employees involved.

(d) Any labor organization seeking to intervene must submit to the Regional Director a statement that it has submitted to the Department and to the Assistant Secretary a roster of its officers and representatives, a copy of its constitution and bylaws, and a statement of its objectives.

(e) The Regional Director may grant intervention to a labor organization in a proceeding involving a petition for clarification of unit or a petition for amendment of recognition or certification filed pursuant to § 1422.2(c), or a petition for determination of eligibility for dues allotment filed pursuant to § 1422.2(d), based on a showing that the proposed clarification, amendment or dues allotment affects that labor organizations's existing exclusively recognized unit(s) in that it would cover one or more employees who are included in such unit(s).