D.C. Mun. Regs. tit. 3, r. 3-425
The record shall be closed at the end of the public hearing, except that the record may be kept open for a stated period for the receipt of specific exhibits, information, or legal briefs, as directed by the Board.
In a contested case proceeding conducted pursuant to § 423, the Board may allow the parties to a case an opportunity to file written responses to any exhibits, information, or briefs submitted after the close of the hearing.
In a rulemaking proceeding conducted pursuant to § 422, the Board may allow persons an opportunity to file written responses to any exhibits, information, or briefs submitted within the period designated by the Board.
The Board reserves the right to reopen the record at any time prior to the issuance of a final decision. In a proceeding, pursuant to § 423, a notice of reopening the record shall be served upon all parties to the proceeding.
D.C. Mun. Regs. tit. 3, r. 3-425