In an extension of cooperative federalism practices between co-regulators, U.S. EPA this week signed a final rule approving Arizona Department of Environmental Quality oversight of the underground injection control (UIC) program for wells classes I through VI. This follows a May 19 Federal Register notice of U.S. EPA receiving a completed primacy application from the state and notice of proposed rulemaking to grant primacy, also reported by ECOS.
Arizona submitted its UIC primacy application to Region 9 in February 2024. In announcing its primacy approval, ADEQ Water Quality Division Director Trevor Baggiore noted, “With primacy, we can make decisions faster and tailor oversight to Arizona’s unique groundwater conditions to better protect our water resources.” Arizona did not previously have primacy for any UIC well classes.
North Dakota, Wyoming, Louisiana, and West Virginia are also approved for Class VI well permitting programs that allow for geologic carbon sequestration. A June 17 Federal Register notice indicated EPA’s receipt of a completed application and NPRM for Texas to oversee a Class VI well permit program with approval expected in the coming months. Louisiana issued its first Class VI well permit on September 5.
