Section 8-632.02 - Defenses(a) A person shall not be liable pursuant to § 8-632.01(b) if the person establishes, by a preponderance of the evidence, that the release or contamination was caused by any of the following: (3) The migration, flow, or movement of hazardous substances from property owned by a person unrelated to the person asserting the defense;(4) An act or omission of an unrelated third party, if reasonable precautions were taken to prevent foreseeable releases;(5) An act or omission of a third party if the act or omission was reasonably outside the scope of a prior or an existing contractual relationship and the person asserting the defense could not have reasonably foreseen or prevented the act or omission; or(6) An act or omission that occurred prior to the acquisition of the property if due diligence had been exercised in investigating the possible existence of a release or contamination, except that due diligence shall not be required if the property was acquired by inheritance or bequest, through a foreclosure for tax delinquency, or by condemnation for blight or other threats to public health, safety, and welfare.(b)(1) Notwithstanding § 8-632.01, a bona fide prospective purchaser whose potential liability for a release or threatened release is based solely on the purchaser being considered to be an owner or operator of a facility shall not be liable as long as the bona fide prospective purchaser does not impede the performance of a response action or natural resource restoration.(2) If there are unrecovered response costs incurred by the District at a facility for which an owner of the facility is not liable by reason of paragraph (1) of this subsection, and if each of the conditions described in paragraph (3) of this subsection is met, the District shall have a lien on the facility, or may by agreement with the owner, obtain from the owner a lien on any other property or other assurance of payment satisfactory to the Mayor, for the unrecovered response costs.(3) The conditions referred to in paragraph (2) of this subsection are the following: (A) A response action for which there are unrecovered costs of the District is carried out at the facility; and(B) The response action increases the fair market value of the facility above the fair market value of the facility that existed before the response action was initiated.(4) A lien under paragraph (2) of this subsection shall:(A) Be in an amount not to exceed the increase in fair market value of the property attributable to the response action at the time of a sale or other disposition of the property;(B) Arise at the time at which costs are first incurred by the District with respect to a response action at the facility;(C) Be subject to the requirements of subsection (1)(3) [sic] of this section; and(D) Continue until satisfaction of the lien by sale or other means.June 13, 2001, D.C. Law 13-312, § 202, 48 DCR 3804; Apr. 8, 2011, D.C. Law 18-369, § 2(d), 58 DCR 996.