D.C. Mun. Regs. tit. 10-C, § 408
408.1 Any affected person or group other than the applicant wishing to participate as a party in a public hearing shall file the following information with the Mayor's Agent not less than fifteen (15) days before the hearing:
408.2 The Mayor's Agent shall determine whether the person or group qualifies as a party as provided in Chapter 30.
SOURCE: Notice of Final Rulemaking published at 51 DCR 7447 (July 30, 2004).