Clean Air – Environmental and Energy Law Program

Regulatory Tracker

Mercury and Air Toxics Standards

EPA rescinded the 2024 mercury and air toxics standards (MATS) for power plants and reinstated the 2012 MATS.

March 30, 2026

Legal Analysis

EPA’s Final Rule Rescinding 2024 MATS Rule and Reinstating 2012 Standards

The legal foundations, regulatory history, and contested cost-benefit rationale behind EPA’s repeal of the 2024 MATS rule.

March 18, 2026

Quick Takes

EPA Rejects Colorado’s Regional Haze Plan Over Disputed Coal Plant Closure

A quick take on the disapproval of the state’s regional haze SIP revision, including a look at some of the legal arguments raised by commenters against the proposed disapproval.

March 18, 2026

Regulatory Tracker

Ethylene Oxide (EtO) Emissions Standards for Commercial Sterilizers

In March 2026, EPA proposed rolling back many of the 2024 rule’s more stringent emissions limits.

March 17, 2026

Regulatory Tracker

Clean Car Rules — Corporate Average Fuel Economy Standards/Greenhouse Gas Standards

The EPA rescinded the Endangerment Finding and all GHG vehicle standards.

March 12, 2026

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‘The Clean Air Act is the bedrock of U.S. climate regulation, but it cannot do the job alone.’

Jody Freeman in Yale Environment 360: Now is the time to develop climate strategies that can be pursued when the political balance shifts.

March 3, 2026

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Podcast: Unpacking EPA’s Decision to Rescind the Endangerment Finding

Jody Freeman on the history of the Endangerment Finding, EPA’s rescission, and what could happen if it reaches the Supreme Court.

March 2, 2026

Legal Analysis

Eliminating the Foundation: Vulnerabilities in and Implications of EPA’s Endangerment Finding Rescission

Analysis breaking down EPA’s arguments in the final rule and what it could mean for regulating GHG emissions in the future.

March 2, 2026

Regulatory Tracker

EPA VOC and Methane Standards for Oil and Gas Facilities

The Biden EPA finalized three rules regulating methane emissions from the oil and gas sector. One of the rules, the Waste Emission Charge, was repealed using the Congressional Review Act. In Sept. 2025, EPA proposed to delay the GHG reporting rules until 2034. In Nov. 2025, EPA finalized the deadline exemptions for certain provisions regulating methane emissions from new and existing oil and gas sources.

February 24, 2026