415 ILCS 5/22.50
No person shall use, or cause or allow the use of, any site for which a land use limitation has been imposed under this Act in a manner inconsistent with the land use limitation unless further investigation or remedial action has been conducted that documents the attainment of remedial objectives appropriate for the new land use and a new closure letter has been obtained from the Agency and recorded in the chain of title for the site. For the purpose of this Section, the term "land use limitation" shall include, but shall not be limited to, institutional controls and engineered barriers imposed under this Act and the regulations adopted under this Act. For the purposes of this Section, the term "closure letter" shall include, but shall not be limited to, No Further Remediation Letters issued under Titles XVI and XVII of this Act and the regulations adopted under those Titles.
415 ILCS 5/22.50