Instead of broadening the scope of innocent landowner defenses to SECA(the Soil Environment Conservation Act) liabilities as SARA(the Superfund Amendments and Reauthorization Act) and Brownfields Act(the Small Business Liability Relief and Brownfield Revitalization Act) of US do, the current owners should not be immunized from liabilities to attain the swift cleanup of the contaminated sites. There are several reasons to justify why the third defences are not broadened by imposing strict liabilities on the owners: 1) if the purchasing prices properly reflects the fact of whether purchased sites are contaminated or not by the commercial custom`s inquiries, the "polluter pays principles" are ultimately satisfied, 2) it is possible to prevent the occurrence of orphan land and past owners` moral hazard problems, 3) by not imposing burden on the public, equity between the public who have no responsibilities and the parties who are potentially responsible for cleanup are not violated, and 4) since the environmental problems are required to be considered or dealt with before buying the property, it is a good opportunity to strengthen the Constitution that the public should also be in duty bounded to improve the environment, but simply not getting a free ride on the environment.