Mason Corporation is located in Schererville, Lake County, Indiana. The Facility is in a commercial, industrial, and residential area. The Facility has been active since 1949 and reclaims tin from spent solvents, acids, plating baths, and sludges from various industrial processes. Tin-based chemicals have also been manufactured since the 1970s. The Facility property covers approximately seven acres and includes several office, laboratory, manufacturing, and storage and processing buildings; a truck unloading dock; six former settling ponds; aboveground storage tanks; and a product container storage area. An Administrative Order on Consent was served to the facility on June 7, 2005, which requires site-wide corrective action for all Solid Waste Management Units (SWMUs). Mason Corporation is a RCRA regulated facility with interim status for a series of six surface impoundments. The primary contamination of concern is metals, in particular chromium and lead.