Class VI permit applicants must submit a plan to plug the injection well in a manner that protects USDWs [40 CFR 146.82(a)(16); 146.92]. 

The purpose of the UIC Program’s evaluation of the proposed Injection Well Plugging Plan is to ensure that the proposed materials and procedures for injection well plugging are appropriate to the well’s approved construction and the site’s geology and geochemistry. This evaluation is important to ensure that the injection well will not serve as a conduit for fluid movement that could endanger USDWs following cessation of injection. 

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 97. Retrieved from