A Department of Energy (DOE) project has seen carbon dioxide injected for the purpose of enhanced oil recovery at the Cranfield oil field near Natchez, Mississippi, since the middle of July. Now, about six weeks into the injection process, underground monitoring of the injected CO2 has begun. Using scientific instruments will help provide further information as to the way the carbon dioxide moves beneath the surface. The monitoring will also help determine what other instruments may be needed in the future to monitor the CO2 as well as how the geologic formations react to the injected CO2.