Upon timely application, a person may be permitted to intervene in an action before the Board in the following circumstances:
When a party to an action relies upon a claim or defense based upon any statute or executive order administered by a federal or state governmental officer or agency or upon any regulation, order, requirement, or agreement issued or made pursuant to the statute or executive order, the Board may permit the officer or agency, upon timely application, to intervene in the action.
Intervention will not be permitted where to do so would allow circumvention of statutory time limits for challenging a matter or would allow circumvention of limits on qualifying as a party entitled to seek judicial review. The Board, in exercising its discretion, shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties.
A person desiring to intervene shall serve a motion to intervene upon the parties in the manner provided in §404.
A motion to intervene shall state the grounds for intervention and shall be accompanied by a pleading setting forth the claim or defense for which intervention is sought.
D.C. Mun. Regs. tit. 3, r. 3-414