D.C. Mun. Regs. tit. 24, r. 24-1007
No owner, driver, manager, or conductor of any cart or other vehicle shall carry or convey, or cause to be carried or conveyed, in that vehicle any coal, earth, sand, gravel, broken stone, dirt, ashes, paper, and other rubbish; or any loose fluid or offensive articles or matter; or any articles whatsoever; so that these articles shall be scattered, dropped, blown, or spilled from the vehicle.
All vehicles conveying combustible refuse; or foul, dusty, or offensive matter of any sort; shall have tight bodies and be closely and securely covered.
All vehicles conveying waste paper and waste paper products that are baled,sacked, or otherwise carried, shall be closely and securely covered.
No person shall remove or transport any manure over any public highway in any of the more densely populated parts of the District of Columbia; except in a tight vehicle which, if not enclosed, shall be covered with canvas that is secured to the sides and ends of the vehicle so as to prevent the manure from being dropped while being removed, and so as to limit as much as practicable the escape of odors from the manure.
D.C. Mun. Regs. tit. 24, r. 24-1007