D.C. Mun. Regs. tit. 17, r. 17-2112
Each security officer certified under this title, including each person commissioned as a special police officer under the second paragraph of the section entitled "FOR METROPOLITAN POLICE" in An Act Making appropriations to provide for the expenses of the government of the District of Columbia for the fiscal year ending June thirtieth, nineteen hundred, and for other purposes, approved March 3, 1899 (30 Stat. 1057; D.C. Official Code § 5-129.02) , shall wear a uniform approved by the Mayor which is distinctly different from the uniform of the Metropolitan Police Department.
Minimum requirements for the uniform are a white uniform cap or a cap covered with a white cap cover and a uniform outer garment, such as a shirt, blouse, jacket, or overcoat. The outer garment shall have the patches and badges required under § 2113 clearly visible at all times.
White caps or caps covered by white cap covers shall be worn at all times by security officers during performance of duties involving crowd control at special events.
Each security officer shall take due care to prevent his or her uniform from falling into the possession of any unauthorized person.
D.C. Mun. Regs. tit. 17, r. 17-2112