An update from Sara Bergan and Sarah Johnson Phillips

Federal Requirements Under the Underground Injection Control (UIC) Program for Carbon Dioxide (CO2) Geologic Sequestration (GS) Wells See Pre-publication Rule

The rule finalizes minimum federal requirements under the Safe Drinking Water Act for underground injection of carbon dioxide (CO2) for GS purposes. It establishes a new class of well, Class VI, and sets minimum technical criteria  for projects. The guidance covers steps from permitting and site characterization to ongoing monitoring of the CO2 stream, injection wells and CO2 plume to well plugging, post-injection site care and site closure. All criteria are set for the purposes of protecting underground sources of drinking water (USDW) only. The rule covers owners and operators of new CO2 injection wells used for Class VI GS as well as those transitioning CO2 injection wells from Class I,II, or V to Class VI GS.   Notably the final rule, as changed or clarified from the earlier proposed rule, provides for the following:

  • Independent primacy exclusively for Class VI wells under subparagraph §145.1(i) of the final rule;
  • Adaptive rulemaking whereby EPA will review the rulemaking every 6 years to make changes as necessary to incorporate new research, data and information about GS technologies;
  • Reevaluation of the Area of Review (AoR) for GS projects every 5 years in order to address concerns about the inherent uncertainties in modeling CO2 movement and with emerging GS technology;
  • Requirement that owners or operators use direct methods to monitor for pressure changes in the injection zone and to supplement with indirect, geophysical techniques; and
  • Clarification of the requirements necessary to ensure financial resources are available to protect USDWs from endangerment over the long term.

The Final Rule will be published in the Federal Register. Information on the Final Rule and earlier actions can also be found at, under Docket ID No. EPA-HQ-OW-2008-0390.


Final Rule: Mandatory Reporting of Greenhouse Gases: Injection and Geologic Sequestration of Carbon Dioxide See Pre-publication Rule

EPA amended the Greenhouse Gas (GHG) Reporting Program, 40 CFR part 98, to cover GHG monitoring and reporting requirements for owners and operators of facilities conducting GS activities (subpart RR) and of any other facility conducting CO2 injection (subpart UU). The data collected under the GHG Reporting Program will inform EPA policy decisions under the Clean Air Act related to the use of CO2 capture and sequestration (CCS) for mitigating GHG emissions. Owners or operators of GS facilities are required to develop and implement a site-specific Monitoring, Reporting and Verification (MRV) plan that would be used to verify the amount of CO2 sequestered and quantify any emissions leaks.


All UIC permitted Class VI wells will be covered under subpart RR. Enhanced oil and gas recovery (EOR) projects using CO2 will be covered under subpart UU, but could be covered by subpart RR if they choose to opt in or apply for a Class VI well permit. Opting into subpart RR would not, for example, require an existing EOR project with a UIC Class II well permit to obtain a Classs VI permit.


The EPA approval process for the purposes of GHG reporting and verification is separate from the UIC permitting process, and the GHG reporting requirements were developed to minimize overlap with the UIC requirements.  Despite the effort to avoid overlap, both programs require regular reporting on the quantity of CO2 injected (flow rate) but at different frequencies and specifications. There may also be overlap in monitoring for CO2 leakage to the surface, although the UIC purpose in doing so is to protect USDWs whereas the GHG program’s purpose is to assess the efficacy of GS as a climate change mitigation strategy. The GHG rule is drafted to build upon the UIC requirements and accept information obtained under the UIC program where feasible. Research and development projects meeting eligibility requirements are exempt from reporting under subpart RR.


The Final Rule will be published in the Federal Register. Information on the Final Rule and earlier actions can also be found at under Docket ID No. EPA-HQ-OAR-2009-0926.