On September 1, 2026, the Department of the Army officially adopted a categorical exclusion (CATEX) previously established by the Department of Energy, a move poised to significantly streamline environmental review processes for advanced nuclear reactor projects on Army installations. This action, taken under Section 109 of the National Environmental Policy Act (NEPA), reflects a broader federal effort to enhance energy security and operational efficiency for military assets while maintaining environmental stewardship.
The National Environmental Policy Act and Categorical Exclusions
Congress enacted NEPA in 1969 to ensure that federal agencies consider the environmental impacts of their proposed actions and engage the public in this process. Agencies typically determine the appropriate level of environmental review for major federal actions through one of three pathways: an Environmental Impact Statement (EIS) for actions likely to have significant effects, an Environmental Assessment (EA) for actions whose effects are uncertain, or a Categorical Exclusion (CATEX) for actions that normally do not significantly affect the quality of the human environment.
CATEXs are crucial tools for administrative efficiency, allowing agencies to proceed with routine activities without lengthy environmental studies, provided no extraordinary circumstances suggest otherwise. If extraordinary circumstances are identified, the agency must either modify the action to avoid significant effects or determine that, despite the circumstances, no significant impacts will occur, thereby justifying the continued application of the CATEX. Should significant effects remain a possibility, an EA or EIS would then be required.
Section 109: Inter-Agency Adoption and the Fiscal Responsibility Act of 2023
The ability for one federal agency to adopt a CATEX established by another agency is a relatively recent development, authorized by Section 109 of NEPA, which was enacted as part of the Fiscal Responsibility Act of 2023. This provision simplifies the environmental review process across the government by allowing agencies to leverage existing environmental analyses for similar types of actions, rather than requiring each agency to develop its own unique CATEX for comparable activities. To adopt a CATEX under Section 109, an agency must identify the relevant CATEX, consult with the establishing agency to ensure its appropriateness, and notify the public of the adoption.
The DOE CATEX for Advanced Nuclear Reactors
The Department of the Army has adopted DOE CATEX B5.26, which specifically covers the authorization, siting, construction, operation, reauthorization, and decommissioning of advanced nuclear reactors. This CATEX is applicable under two primary conditions: first, that the project's attributes sufficiently reduce the risk of adverse offsite consequences from the release of radioactive or hazardous materials, considering factors like fission product inventory, fuel type, reactor design, and operational plans; and second, that any hazardous waste, radioactive waste, or spent nuclear fuel generated can be managed according to applicable requirements. This categorical exclusion explicitly allows for projects involving multiple reactors within a single nuclear facility.
Army's Intent: Microreactors on Installations
For the Department of the Army, the adoption of DOE CATEX B5.26 is a strategic move to facilitate the deployment of microreactor nuclear power plants (MNPs) on Army installations. The DA anticipates that these advanced reactors will significantly enhance mission capabilities and effectiveness, improve safety, and increase operational efficiencies by providing reliable, resilient energy sources. While the deployment of MNPs is a primary driver, the Army emphasizes that its use of this CATEX will not be limited to this example and can be applied to other appropriate circumstances involving advanced nuclear technologies.
Safeguards and Oversight
Despite the streamlining offered by a CATEX, the Army maintains robust environmental safeguards. The DA's NEPA Implementing Procedures, dated April 30, 2026, guide its consideration of extraordinary circumstances. Furthermore, the Army will also apply the Department of Energy's extraordinary circumstances criteria, found in DOE NEPA Implementing Procedures, Section 5.4(c)(3). This dual approach ensures a thorough evaluation. If an extraordinary circumstance is present, the DA will assess whether the proposed action can be modified to avoid significant adverse effects. If modifications are not feasible or sufficient, and significant impacts are still possible, the DA will then proceed with a more detailed EA or EIS.
Additionally, the Army will evaluate proposed actions against the "Integral Elements" described in Appendix B of DOE's NEPA Implementing Procedures. Each application of this adopted CATEX, along with the consideration of extraordinary circumstances and Integral Elements, will be documented in a Record of Environmental Consideration (REC). This systematic approach ensures transparency and accountability in the environmental review process.
Inter-Agency Consultation and Public Notification
The Department of the Army engaged in close consultation with the Department of Energy on July 29, 2026, to discuss the applicability and appropriateness of the CATEX for DA's proposed actions. Discussions covered the types of actions the CATEX would cover, the specific extraordinary circumstances to consider, the requirement to evaluate Integral Elements, and the necessary documentation for applying the CATEX. This collaborative process culminated in a joint determination that the Army's intended use of the CATEX is appropriate. This Federal Register notice serves as the public notification of this adoption, fulfilling the requirements of Section 109 and making the CATEX immediately available for use by the Army and all DoW Components. The DA will make a minor administrative change to remove "DOE" from the categorical exclusion text to align with recent Council on Environmental Quality guidance on CATEX adoptions.
