<p>The Soil Environment Conservation Act imposes strict liability on a person causing soil contamination. In particular, a person who satisfies any of the following categories is regarded as a Polluter for Act purposes: (i) persons who own, occupy or operate certain facilities subject to the control of specific soil contamination (“Controlled Facilities”) which have been a cause for soil contamination at the time of occurrence of soil contamination or (ii) persons who have taken over the Controlled Facilities (Article 10-3 (3) of the old Soil Environment Conservation Act1, the “Polluter Clause”. The claimant purchased land from a steel company on March 25, 2003 for housing construction. The land had previously been used as the steel company’s steel plant site, and the level of contamination of the land surveyed on October 2006 exceeded the threshold of determining existence of soil contamination set forth in the Act. Determining the claimant as a “persons who have taken over the facilities” under a provision of the Polluter Clause, the mayor of Masan ordered the claimant to clean up the site on September 28, 2007. The claimant filed a constitutional appeal, arguing that the foregoing provision of the Polluter Clause imposes liability on a purchaser of a land with respect to soil contaminating actions that were conducted prior to the implementation of the Polluter Clause, which is essentially a violation of the principle against retroactive legislation and principle of trust protection. The Constitutional Court ruled that the contested provision of the Polluter Clause does not violate the principle against retroactive legislation but does violate the principle of trust protection. A person who acquired Controlled Facilities before implementation of the disputed provision must have expected that they would only be liable for unlawful actions under the ordinary negligence standard based on the Civil Code of Korea. Therefore, imposing strict liability upon their actions based on a law implemented after the conduct of such actions is a violation of the principle of trust protection.</p>