The Class VI Rule requires owners or operators to develop and submit an AoR and Corrective Action Plan as part of their permit application [40 CFR 146.82(a)(4),(13); 146.84(b)]. The plan must document the owner or operator’s compliance with the AoR delineation requirements (including the AoR delineation modeling approach), present a comprehensive strategy for AoR reevaluations over the duration of the project, and describe how any necessary corrective action will be conducted. 

The purpose of the UIC Program’s evaluation of the AoR delineation approach is to assess whether the AoR, as modeled, appropriately represents the area in which USDWs may be endangered by the injection operation, as specified by the Class VI Rule requirements. The delineation of the AoR relies on site characterization and proposed operational data (and the evaluation of the AoR delineation should consider this information). It also informs and supports the development and evaluation of other components of the permit application (such as the determination of site-suitability and strategies for compliance with the testing and monitoring, financial responsibility, and emergency and remedial response requirements). 

The UIC Program should also review all corrective action information to ensure that all artificial penetrations that may allow fluid movement into USDWs in the AoR are identified and appropriately addressed by corrective action to ensure that they do not serve as conduits for fluid movement. 

Source: Environmental Protection Agency. (2018, January). Geologic Sequestration of Carbon Dioxide Underground Injection Control (UIC) Program Class VI Implementation Manual for UIC Program Directors.  Page 69. Retrieved from