(2) The potentially responsible party is the owner of the real property on or in which the facility is located, and did not conduct or permit the generation, transportation, storage, treatment, or disposal of any hazardous substance at the facility, and did not contribute to the release or threat of release of a hazardous substance at the facility through any action or omission. This subsection shall not apply if the potentially responsible party purchases the real property with actual or constructive knowledge that the property was used for the generation, storage, treatment, or disposal of any hazardous substance.