The Republic Steel Corp. Quarry (RSQ) site is located near the Black River in Elyria, Ohio. It consists of a 5-acre quarry containing water and 7 acres of fenced land surrounding the quarry. From 1950 to 1975, the Republic Steel Corporation discharged about 200,000 gallons per day of waste pickle liquor and rinse water, consisting of sulfuric acid and dissolved metal oxides, into the quarry via a ditch. Sampling later found groundwater beneath the site was contaminated with heavy metals. In 1977, Republic Steel sold the quarry and surrounding land to the City of Elyria. EPA placed the site on its Superfund program National Priorities List (NPL) of hazardous waste sites in June 1986.