Trump EPA Continues to Clear Backlogged State Implementation Plans in Oklahoma
DALLAS, TEXAS (Oct. 8, 2026) – Today, U.S. Environmental Protection Agency (EPA) approved final revisions to Oklahoma’s State Implementation Plan (SIP) for the interstate transport of Sulfur Dioxide (SO2) that was submitted in 2021, marking the 15th SIP approval for the state in 2026. This action further reduces the backlog of SIPs left by the Biden Administration and confirms that Oklahoma’s plan meets all Clean Air Act (CAA) requirements for SO2 transport. Approving SIPs on time provides certainty to local businesses, strengthens cooperative federalism, and advances EPA’s mission to protect human health and the environment, while allowing the economy to continue to grow.
“Over the past year, EPA Region 6 has worked diligently to clean up the mess left behind by the Biden Administration and give Oklahoma more control over its air program,” said Regional Administrator Scott Mason. “Today’s action is a perfect example of Administrator Zeldin’s efforts to promote cooperative federalism, give Oklahoma businesses more certainty, and provide all Americans with clean air to breathe.”
EPA’s approval confirms Oklahoma’s SIP has provisions to ensure emissions of SO2 in the state will not significantly affect air quality in neighboring states. To support this decision, EPA considered air quality, emission sources, modeling, and emission trends in Oklahoma and bordering states to identify any sources and emission activities that could potentially impact the downwind air quality in other states. EPA found that Oklahoma’s SIP complies with the CAA requirements and there are no SO2 nonattainment concerns in any other state as a result of emissions from Oklahoma sources or emission activities. EPA will continue to work with the state of Oklahoma to develop and approve common sense environmental plans that protect Americans and provide regulatory certainty for businesses.
The final notice and docket materials are available at regulations.gov under docket ID EPA-R06-OAR-2025-2270.
Background
The Clean Air Act (CAA) requires states to develop State Implementation Plans (SIPs). The SIP is a general plan to attain and maintain the National Ambient Air Quality Standards (NAAQS) in all areas of the country, and a specific plan to attain the standards for each area designated nonattainment for a NAAQS. The core purpose of a SIP is to enforce air standards, reduce pollution, and demonstrate compliance with CAA standards.
Earlier this year, EPA cleared over two decades of backlogged SIPs in Oklahoma by acting on 13 SIP revisions submitted between 2002 and 2025. Clearing the enormous SIP backlog left over from previous administrations is key to achieving EPA Administrator Lee Zeldin’s mission to protect the environment and grow the economy.
For more information on SIPs, visit our webpage.
Connect with the Environmental Protection Agency Region 6 on Facebook, X, Instagram, or visit our homepage.