(1) An act of God.

(2) An act of war.

(3) An act or omission of a third party other than an employee, agent or contractor of the responsible person or one whose act or omission occurs in connection with an agreement or contractual relationship (except where the sole contractual arrangements arise either from a published tariff and acceptance for carriage by a common carrier by rail, or an exempt circular or transportation contract in lieu of a published tariff for carriage by a common carrier by rail), if the responsible person:

(1) at the time of acquisition, did not know and had no reason to know, that a hazardous substance which is the subject of the release or threatened release was disposed on, in or at the site. For purposes of this paragraph, the owner must have undertaken, at the time of acquisition, all appropriate inquiries into the previous ownership and uses of the property consistent with good commercial or customary practice in an effort to minimize liability. The department shall take into account specialized knowledge or experience on the part of the owner, the relationship of the purchase price to the value of the property if uncontaminated, commonly known or reasonably ascertainable information about the property, the obviousness of the presence or likely presence of contamination at the property and the ability to detect the contamination by appropriate inspection; and

(2) after obtaining actual knowledge of the presence of a hazardous substance on, in or at the site, exercised due care with respect to the hazardous substance concerned, taking into consideration the characteristics of the hazardous substance, in light of all relevant facts and circumstances and took precautions against foreseeable acts or omissions of any such third party and the consequences that could foreseeably result from those acts or omissions.