Editors' Summary: This Article addresses CERCLA's language and structure as it pertains to the liability of interim landowners for passive migration of hazardous substances. The author argues that CERCLA's language, structure, and policies compel the conclusion that passive migration of hazardous substances during ownership does not trigger CERCLA liability. The author first addresses the language of CERCLA, and concludes that the CERCLA definition of "disposal" does not include the passive migration of hazardous substances. The definition of disposal requires active human conduct, and Congress explicitly referred to the concept of passive migration in the CERCLA definition of release. Next, the author asserts that imputing a passive meaning to disposal negates the purpose of the innocent landowner defense. If disposal included passive migration, there would be no time after the disposal of hazardous substances when one might innocently acquire a facility. Last, the author argues that rejecting passive migration as a basis for interim owner liability is in accord with the congressional objectives of CERCLA. Interim landowners who solely permit migration of wastes should not be held liable, but interim landowners who knowingly transfer contaminated property can still be liable under CERCLA and state civil and criminal law. And operators, prior owners who actively disposed of hazardous wastes, arrangers, and transporters of hazardous wastes will all remain strictly liable for the cleanup costs of a contaminated site.