The Applicability This subpart establishes criteria and standards for underground injection control programs to regulate any Class VI carbon dioxide geologic sequestration injection wells [40 CFR 146.81].

The Class VI permit information requirements establish the information that owners or operators must submit to obtain a Class VI permit [40 CFR 146.82]

The minimum criteria for siting establish that Class VI wells must be located in areas with a suitable geologic system, including an injection zone that can receive the total anticipated volume of carbon dioxide and confining zone(s) to contain the injected carbon dioxide stream and displaced formation fluids [40 CFR 146.83].

The AoR and corrective action provisions require the use of computational modeling to delineate the AoR for proposed Class VI wells and the preparation of, and compliance with, an AoR and Corrective Action Plan for delineating the AoR, performing all necessary corrective action, and periodically reevaluating the AoR and amending the plan if needed [40 CFR 146.84]. 

The financial responsibility requirements establish that owners or operators must demonstrate and maintain financial responsibility for performing corrective action on improperly abandoned wells in the AoR, injection well plugging, post-injection site care (PISC) and site closure activities, and emergency and remedial response [40 CFR 146.85].

The injection well construction requirements specify the design and construction of Class VI wells using materials that are compatible with the carbon dioxide stream over the duration of the Class VI project to prevent the endangerment of USDWs [40 CFR 146.86].

The requirements for logging, sampling, and testing prior to operation outline activities, including logs, surveys, and tests of the injection well and formations, that must be performed before injection of carbon dioxide may commence [40 CFR 146.87].

The injection well operating requirements provide operational measures for Class VI wells to ensure that the injection of carbon dioxide does not endanger USDWs, along with limitations on injection pressure and requirements for automatic shut-off devices [40 CFR 146.88].

The mechanical integrity requirements specify continuous monitoring to demonstrate internal mechanical integrity and annual external mechanical integrity tests [40 CFR 146.89]

The testing and monitoring requirements define the elements that must be included in the required Testing and Monitoring Plan submitted with a Class VI permit application and implemented throughout the project to demonstrate the safe operation of the injection well and track the position of the carbon dioxide plume and pressure front [40 CFR 146.90].

The reporting requirements establish the periodic timeframes and circumstances for the electronic reporting of Class VI well testing, monitoring, and operating results and requirements for keeping records [40 CFR 146.91].

The injection well plugging requirements specify that a Class VI injection well must be properly plugged to ensure that the well does not become a conduit for fluid movement into USDWs in the future [40 CFR 146.92].

The post-injection site care (PISC) and site closure requirements address activities that occur following cessation of injection. The owner or operator must continue to monitor the site for 50 years following the cessation of injection, or for an approved alternative timeframe, until it can be demonstrated that no additional monitoring is needed to ensure that the project does not pose an endangerment to USDWs; following this, they must plug the injection and monitoring wells and close the site [40 CFR 146.93].

The emergency and remedial response requirements specify that owners or operators of Class VI wells must develop and maintain an approved Emergency and Remedial Response Plan that describes the actions to be taken to address events that may cause endangerment to a USDW or other resources [40 CFR 146.94].

The Class VI injection depth waiver requirements provide a process under which Class VI well owners or operators can seek a waiver from the injection depth requirements in order to inject carbon dioxide into non- USDWs that are located above or between USDWs. Including injection depth waiver provisions in a state’s regulation is optional [40 CFR 146.95].