In situ chemical reduction, or “ISCR,” uses chemicals called “reducing agents” to help change contaminants into less toxic or less mobile forms. It is described as “in situ” because it is conducted in place, without having to excavate soil or pump groundwater above ground for cleanup. ISCR can clean up several types of contaminants dissolved in groundwater. ISCR is most often used to clean up the metal chromium and the industrial solvent trichloroethene (TCE).