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In a significant move towards bolstering carbon capture and storage (CCS) efforts, the U.S. Environmental Protection Agency (EPA) has granted Arizona the authority to oversee all classes of underground injection wells under the Safe Drinking Water Act (SDWA).

This decision marks Arizona as the fifth state to gain primacy for Class VI wells, which are pivotal in the permanent underground storage of carbon dioxide. By transferring permitting responsibilities to the Arizona Department of Environmental Quality (ADEQ), the EPA recognizes the state's capability to manage its underground water resources while simultaneously fostering carbon management opportunities and economic growth.

EPA Administrator Lee Zeldin emphasized the necessity of efficient permitting processes, noting that states are uniquely positioned to balance resource protection with business interests. "States know their water resources best," he asserted, highlighting that this move will streamline regulatory frameworks and stimulate investment in CCS technologies. Class VI wells are particularly noteworthy among the various well classes under the SDWA, as they facilitate the injection of CO2 into deep geological formations, effectively preventing its release into the atmosphere and contributing to climate change.

Arizona's newfound authority to regulate Class VI wells comes at a crucial time as the nation aims to expand its CCS infrastructure. With this approval, the ADEQ can now directly issue permits for CO2 storage projects, ensuring both regulatory oversight and alignment with local environmental conditions. This shift is anticipated to attract private sector investments, thereby accelerating the deployment of CCS technologies across the region.

While the EPA will maintain oversight of the underground injection control program within Arizona, it will continue to serve as the permitting authority on tribal lands, with the exception of Class II wells on Navajo Nation lands, where primacy has already been established. By granting Arizona this significant authority over Class VI wells, the federal government underscores its support for states poised to lead in advancing carbon storage—a critical component of the U.S. climate and energy strategy moving forward.