D.C. Code § 8-113.01

For the purposes of this subchapter, the term:
(1) “Facility” means 1 or more underground storage tanks at a given location.
(2) “Guarantor” means any person, other than the owner or operator, who provides evidence of financial responsibility for the underground storage tank facility.
(3) “Operator” means any person in control of, or having responsibility for, the daily operation of a facility.
(4) “Owner” means:
(A) In the case of an underground storage tank in use on or after November 8, 1984, any person who owns an underground storage tank used for the storage, use, or dispensing of regulated substances; or
(B) In the case of any underground storage tank in use before November 8, 1984, but no longer in use on that date, any person who owned a tank immediately before discontinuation of its use.
(5) “Person” means any individual, partnership, corporation (including a government corporation), trust, firm, joint stock company, association, consortium, joint venture, commercial entity, state, municipality, commission, political subdivision of a state, the District of Columbia (“District”) government, the United States government, a foreign government, or any interstate body.
(6) “Petroleum” means petroleum, including crude oil or any fraction of crude oil, that is liquid at standard conditions of temperature and pressure of 60 degrees Fahrenheit and 14.7 pounds per square inch absolute.
(7) “Regulated substance” means:
(A) Any substance defined in § 101(4) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, approved December 11, 1980 (94 Stat. 2767; 42 U.S.C. § 9601(14)). The term “regulated substance” shall not include any substance regulated as a hazardous waste under subtitle C of title II of the Solid Waste Disposal Act, approved October 21, 1976 (90 Stat. 2806; 42 U.S.C. § 6921 et seq.);
(B) Petroleum; or
(C) Any other substance designated by the Mayor in accordance with rules issued pursuant to § 8-113.12 .
11, 1980 (94 Stat. 2767; 42 U.S.C. § 9601(14)). The term “regulated substance” shall not include any substance regulated as a hazardous waste under subtitle C of title II of the Solid Waste Disposal Act, approved October 21, 1976 (90 Stat. 2806; 42 U.S.C. § 6921 et seq.);
(B) Petroleum; or
(C) Any other substance designated by the Mayor in accordance with rules issued pursuant to § 8-113.12 .
(8) “Release” means any spill, leak, emission, discharge, escape, leach, or disposal from an underground storage tank.
(9) (A) “Responsible party” means:
(i) An owner or operator as defined in this section;
(ii) A person who caused or contributed to a release from an underground storage tank system;
(iii) A person who caused a release as a result of transfer of a regulated substance to or from an underground storage tank system;
(iv) A person found to be negligent, including any person who previously owned or operated an underground storage tank or facility, or who arranged for or agreed to the placement of an underground storage tank system by agreement or otherwise; or
(v) The owner of real property where an underground storage tank is or was located or where contamination from an underground storage tank is discovered if the owner or operator of the tank as defined in paragraphs 3 and 4 cannot be located or is insolvent, or, if the real property owner refuses without good cause to permit the owner or operator of the tank access to the property to investigate or remediate the site.
(B) If the owner and operator of a petroleum underground storage tank are separate persons, only the owner shall be required to demonstrate financial responsibility. Both the owner and operator shall be liable in the event of noncompliance with the requirements of 40 C.F.R. 280.90 et seq.
use to permit the owner or operator of the tank access to the property to investigate or remediate the site.
(B) If the owner and operator of a petroleum underground storage tank are separate persons, only the owner shall be required to demonstrate financial responsibility. Both the owner and operator shall be liable in the event of noncompliance with the requirements of 40 C.F.R. 280.90 et seq.
(10) “Underground storage tank” means 1 or any combination of tanks, including underground pipes that connect tanks, that is used to contain an accumulation of regulated substances, and the volume of which (including the volume of the underground pipes connected thereto) is 10% or more beneath the surface of the ground. “Underground storage tank” does not mean a tank that is exempted in accordance with rules issued pursuant to § 8-113.12 .