The Loudon Oil Field site was one of three Enhanced Oil Recovery (EOR) field validation tests conducted by the MGSC to assess potential for CO2 storage in oil in the Illinois Basin. The project was supported by the U.S. Department of Energy (DE-FC26-05NT42588) and the Illinois Department of Commerce and Economic Opportunity. CO2 was injected at the Loudon Oil Field test site in Fayette County, IL into the Cypress Sandstone, a 1,500 feet deep sandstone formation. A cumulative 43 tons of CO2 was injected, and the oil production rate peaked at 8 bopd with sustained oil rate of 1–2 bopd above the pre-CO2 injection rate. Baseline, injection, and post-injection monitoring were conducted until two years after the initial CO2 injection.