Liability for environmental harm: the innocent landowner defenses in comparative law perspective

One of the most relevant issue concerning liability for environmental harm is whether and to what extend the owner of a polluted land who did not contribute to the environmental harm can be asked to pay for the cleanup of the polluted site. Indeed, regarding historical contamination, it is not always possible to find the person who is responsible for the contamination or this person may be a company that went bankrupt and is insolvent. Thus in this case, who will bear the costs of cleanup? The owner of the polluted land or the collectivity (through an administrative process?).