EPA Advances Cooperative Federalism to Improve Air Quality by Taking an Important Step to Reconsider Biden-era “Good Neighbor Plan”

WASHINGTON -On January 27, 2026, the U.S. Environmental Protection Agency (EPA) proposed phase 1 of its reconsideration of the deeply flawed Biden-era "Good Neighbor Plan." Under phase 1, the agency is proposing to approve eight states' State Implementation Plans (SIPs) pertaining to the 2015 eight-hour ozone National Ambient Air Quality Standards (NAAQS). If finalized, Alabama, Arizona, Kentucky, Minnesota, Mississippi, Nevada, New Mexico, and Tennessee would no longer need to worry about another "Good Neighbor Plan" and could implement the remainder of their SIPs.

Today's proposal demonstrates the Trump EPA's commitment to advance cooperative federalism and recognizes the important responsibility EPA shares with our state air agency partners to ensure clean air for all Americans. In stark contrast, the Biden EPA disapproved the 2015 eight-hour ozone NAAQS SIPs for Alabama, Kentucky, Minnesota, Mississippi, and Nevada; proposed to disapprove portions of the SIPs for Arizona, New Mexico, and Tennessee, and proposed error corrections on previous SIP approvals for Iowa and Kansas, claiming the states did not include sufficient provisions to control ozone emissions that travel across state lines. These decisions were made despite these states properly using EPA-supported modeling and thresholds to demonstrate they were not interfering with the attainment of the NAAQS in other states. The Biden-Harris administration took it a step further by improperly finalizing the "Good Neighbor Plan," which mandated strict emission controls for power plants, natural gas pipelines, cement and cement product manufacturing, iron and steel mills and ferroalloy manufacturing, glass and glass product manufacturing, metal ore mining, basic chemical manufacturing, petroleum and coal products manufacturing, pulp, paper, and paperboard mills, and solid waste combustors or incinerators across 20 states, including six of the states mentioned in today's action. This was despite 21 states demonstrating they did not need to address emissions activity within the state in order to not interfere with other states' ability to meet CAA standards. In June 2024, the U.S. Supreme Court stayed the rule, finding that it was likely unreasonable and irrational in key respects. Additionally, two other federal courts vacated EPA's SIP disapprovals for Kentucky and Mississippi.

"The Trump EPA has shown that when we advance cooperative federalism, we are better able to protect human health and the environment," said EPA Administrator Lee Zeldin. "Today, we are taking an important step to undo a Biden Administration rule that treated our state partners unfairly. If the SIPs are approved as proposed, these states will be able to advance cleaner air now for their communities, instead of waiting for overly burdensome federal requirements years from now."

If finalized, EPA's proposal will be a key step in addressing the Biden-era heavy-handed, one-size-fits-all, federal mandate, resolving the "interstate transport" obligations for the 2015 eight-hour ozone NAAQS, and restoring the rule of law. The "interstate transport" provision requires that each state's SIP contain provisions to prohibit emissions within the state from significantly contributing to nonattainment or interfering with maintenance of the NAAQS in other states. As proposed in this rule, EPA finds that the eight SIPs have adequate data demonstrating these states are not interfering with ozone attainment for the 2015 eight-hour ozone NAAQS in other states. This action also indicates EPA's intent to withdraw the proposed error correction from approval to partial disapproval of two additional states' SIP submissions.

EPA is committed to providing clean air for all Americans. In the near future, EPA intends to take a separate action, consistent with this proposal, to address "interstate transport" obligations for the remaining states covered in the final "Good Neighbor Plan," including areas of Indian Country located within the geographic bounds of the covered states.

EPA will hold a 30-day public comment period on the proposal following publication in the Federal Register. Read the proposal.

Background

On October 1, 2015, EPA promulgated a new 8-hour ozone NAAQS of 70 ppb. The CAA requires states to develop and send to EPA for review SIP submissions containing adequate provisions prohibiting significant contribution to nonattainment or interference with maintenance of the NAAQS in other states.

In June 2024, the U.S. Supreme Court stayed enforcement of the "Good Neighbor Plan" pending judicial review (Ohio v. EPA. 144 S. Ct. 2040 (2024)). EPA has taken administrative action to stay the "Good Neighbor" Plan in its entirety in all 23 states.

On March 12, 2025, EPA Administrator Lee Zeldin announced the agency is tackling the troubled "Good Neighbor Plan." This announcement followed a declaration EPA filed with the D.C. Circuit on March 10, 2025, indicating it would reconsider the scope of states, the scope of sources, and the definition of significant contribution for the "Good Neighbor Plan". Since the spring of 2025, litigation over the "Good Neighbor Plan" and 2023 SIP disapproval has been put into abeyance pending EPA's reconsideration decisions.