Missouri Code of State Regulations
Title 8 - DEPARTMENT OF LABOR AND INDUSTRIAL RELATIONS
Division 40 - State Board of Mediation
Chapter 2 - General Rules
Section 8 CSR 40-2.130 - Intervention

(1) Any third party having a legitimate interest in any proceedings may file a petition of intervention setting forth facts sufficient to establish such interest and requesting that the board resolve contested factual matters in its favor. For purposes of third-party intervention, legitimate interest shall be determined by the board and any approved intervenor must be able to prove it is authorized to represent at least ten percent (10%) of the employees within a proposed bargaining unit. If the board determines intervenor has provided an adequate showing of interest pursuant to 8 CSR 40-2.070, all parties shall be notified of the determination prior to the start of any hearing. Any organization which has a signed, valid collective bargaining agreement encompassing the proposed bargaining unit, or any portion, shall be considered to have a legitimate interest in any proceedings upon presentation of same.