Regulatory Tracker

EPA rescinded the 2024 mercury and air toxics standards (MATS) for power plants and reinstated the 2012 MATS.

Through two state plan approvals, EPA finalized a new policy that eases all states’ Regional Haze planning obligations. Environmental groups are challenging the approvals.

EPA establishes the baseline requirements for new source review (NSR) permits, which are then issued by state and local air pollution agencies. In 2025, EPA made multiple changes to the NSR program easing permitting requirements for new and existing sources.

The Clean Air Act’s Good Neighbor provision requires upwind states to ensure that their instate sources do not contribute to downwind states’ attainment of the NAAQS. On Mar. 12, 2025, EPA announced its plan to roll back the Biden administration’s Good Neighbor Plan, which the Supreme Court stayed in June 2024.

Under the Trump executive order Regulatory Freeze Pending Review, the Biden administration’s final rule setting deadlines for states to submit SIPs for nonattainment areas did not go into effect. On June 3, 2025, EPA announced its plans to reconsider the rule.

On March 12, 2025, EPA announced a reconsideration of the NAAQS.

In June 2025 EPA proposed a rule rolling back the 2024 EPA standards for GHG emissions from existing coal-fired power plants and new gas-fired power plants.

In early January 2025, the Biden EPA withdrew its direct final rule and indicated it would release a subsequent rule addressing the 13 states that failed to submit state implementation plan revisions.

EPA sets NAAQS for six common and harmful pollutants: carbon monoxide, lead, PM, ozone, nitrogen dioxide, and sulfur dioxide.