D.C. Code § 8-1445: Defenses to liability.

There shall be no liability under § 8-1442 for a person otherwise liable who can establish by a preponderance of the evidence that the costs resulting from their acts or omissions were caused solely by:

(1)

An act of God;

(2)

An act of War;

(3)

An act or omission of a third party other than an employee or agent of the defendant, or other than one whose act or omission occurs in connection with a contractual relationship, existing directly or indirectly, with the defendant, if the defendant establishes by a preponderance of the evidence that the defendant:

(A)

Exercised due care with respect to the hazardous substance concerned, taking into consideration the characteristics of such hazardous substance, in light of all relevant facts and circumstances; and

(B)

Took precautions against foreseeable acts or omissions of any such third party and the consequences that could foreseeably result from such acts or omissions; or

(4)

Any combination of the foregoing paragraphs.