The Environmental Protection Agency announced on March 19, 2026, a proposed rule to grant the State of Colorado primary enforcement responsibility, or primacy, for Class VI underground injection control wells under the Safe Drinking Water Act. This action would empower Colorado's Energy and Carbon Management Commission to issue permits and enforce regulations for wells used in geologic carbon sequestration, excluding those on Indian lands where the EPA retains authority. The proposal stems from Colorado's October 7, 2025, application, which the EPA has deemed complete and compliant with federal requirements outlined in 40 CFR parts 144, 145, and 146. This development is significant as it aligns with broader efforts to address climate change through carbon capture and storage, potentially streamlining permitting processes within the state while ensuring protection of underground sources of drinking water.
Background on the UIC Program and Class VI Wells
The Safe Drinking Water Act establishes the Underground Injection Control program to safeguard underground sources of drinking water from contamination by injected fluids. Under section 1422 of the act, states can apply for primacy to administer their own UIC programs, provided they meet federal standards. Class VI wells, a category introduced to regulate the injection of carbon dioxide for long-term geologic sequestration, involve injecting carbon dioxide into deep rock formations to prevent its release into the atmosphere.
Federal regulations in 40 CFR part 146 detail stringent requirements for Class VI wells, including site characterization to confirm containment, predictive modeling of the carbon dioxide plume, well construction standards to prevent leaks, ongoing monitoring of injection pressure and groundwater quality, and financial assurances for project phases up to site closure. As noted in the Federal Register entry, these safeguards ensure that injection activities do not endanger underground sources of drinking water, defined as aquifers capable of supplying public water systems.
Colorado already holds primacy for Class II wells since 1984, as referenced in the entry (49 FR 13040). The current proposal extends this authority to Class VI, reflecting the state's growing interest in carbon management technologies amid national climate goals.
Colorado's Path to Primacy Application
Colorado's journey toward Class VI primacy involved extensive legislative and regulatory steps. In 2023, state law SB23-016 expanded the Energy and Carbon Management Commission's jurisdiction to include geologic storage operations. This was followed by a rulemaking process from June to December 2024, culminating in finalized Class VI rules on December 16, 2024.
The state conducted robust public participation, as required by 40 CFR 145.31. This included hybrid stakeholder engagements, public hearings, and outreach to tribes and communities. For instance, the Energy and Carbon Management Commission hosted seven general stakeholder meetings, targeted sessions, and a carbon management tour near potential project sites. In February 2025, notices were published in seven newspapers and online, inviting input on the primacy application. During a 30-day comment period, only one oral comment was received, expressing concerns about carbon capture projects and related tax credits, but it did not prompt changes to the application, according to the state's responsiveness summary.
The application package, submitted on October 7, 2025, included a program description, copies of statutes and regulations, an Attorney General's statement affirming legal authority, and a Memorandum of Agreement with EPA Region 8. These elements demonstrate Colorado's adherence to federal procedures under SDWA section 1422.
EPA's Evaluation of the Application
The EPA conducted a thorough review to verify that Colorado's program satisfies SDWA requirements. As detailed in the Federal Register, the agency assessed the state's statutes, regulations, and administrative framework against 40 CFR parts 144, 145, and 146. Key findings include confirmation that Colorado's rules incorporate federal technical standards for site characterization, well construction, monitoring, and financial responsibility.
The Attorney General's statement, dated May 27, 2025, certifies adequate enforcement powers, including civil and criminal authorities. The Memorandum of Agreement, signed October 8, 2025, outlines coordination between the state and EPA, such as joint oversight and information sharing. The EPA also evaluated the state's compliance evaluation program, staffing, and public participation processes, concluding that Colorado has the resources and procedures to implement an effective program.
This evaluation highlights differing perspectives: proponents view primacy as a means to accelerate carbon sequestration projects by localizing permitting, while skeptics, as reflected in the single public comment, worry about environmental risks and project viability, referencing incidents like the Archer-Daniels-Midland case outside Colorado.
Proposed Action and Oversight
The EPA proposes amending 40 CFR 147.301 to incorporate Colorado's Class VI statutes and regulations by reference, making them federally enforceable. This includes provisions from the Colorado Administrative Procedure Act, the Oil and Gas Conservation Act, and Energy and Carbon Management Commission rules effective December 16, 2024.
Upon approval, the EPA would maintain oversight through quarterly noncompliance reports and annual performance reviews, as specified in the Memorandum of Agreement. The proposal excludes Indian lands, preserving EPA primacy there.
Public input is invited until May 4, 2026, with a virtual hearing scheduled, details available at https://epa.gov/uic/co-primacy. This process underscores the EPA's commitment to transparency.
In summary, this proposal positions Colorado to lead in regulating geologic sequestration, balancing environmental protection with innovation. Potential next steps include final EPA approval following public comments, after which the state could begin issuing Class VI permits. Ongoing debates may focus on integrating this program with federal incentives like the 45Q tax credit, while addressing community concerns about safety and equity. Challenges could arise in coordinating with adjacent states or handling cross-border projects, highlighting the need for continued federal-state collaboration.
