Last mentioned: Mar 20, 2026
Across the most recent 5 stories covering Clean Air Act — 20% positive, 80% negative sentiment, averaging 7.6/10 impact.
This entity profile aggregates every story where the entity meets our minimum relevance threshold before it is linked here — a story naming this entity only in passing, as competitive context for an unrelated subject, does not qualify. That threshold exists because earlier testing surfaced entity pages cluttered with tangential mentions: a story about two unrelated companies merging could otherwise populate a third company's page simply because it was named once for comparison, with no real event of its own. The timeline below reflects genuine milestones and developments specific to this entity, cross-referenced against the same source-verification standard applied to every story on this site. Sentiment measures the directional read of each development for this entity specifically, not the overall tone of the reporting, and impact weights how consequential a development is rather than how widely it was syndicated across outlets.
Figures are computed live from our source-verified story record — see our methodology for how impact and sentiment are derived.
The Trump administration EPA officially revokes the 2009 scientific finding.
Public health and environmental groups file the first lawsuit against the repeal.
24 states and 10 cities file a major challenge in the D.C. Circuit Court of Appeals.
States File Lawsuit
A coalition of states sues to block the repeal, alleging it violates the Clean Air Act.
Multi-State Lawsuit Filed
A coalition of 23 states and 14 cities sues the EPA in the D.C. Circuit Court of Appeals.
Repeal Announced
The Trump EPA formally moves to repeal the 2009 finding, citing a need for deregulation.
Public Outcry
Massive influx of public letters and editorials published in regional news outlets across the U.S.
RMP Revisions
EPA proposes rolling back Risk Management Program safety standards for industrial facilities.
Social Cost Revision
New guidelines set the economic value of human life and carbon mitigation to zero in cost-benefit models.
Endangerment Repeal
EPA formally rescinds the 2009 finding that GHGs threaten public health.
Trump Revokes Finding
The Trump administration formally terminates the 2009 conclusion to halt climate regulations.
Endangerment Finding Issued
EPA officially determines that six greenhouse gases threaten the health of current and future generations.
Endangerment Finding Issued
The EPA under President Obama officially declares greenhouse gases a threat to public health.
Massachusetts v. EPA
Supreme Court rules EPA has authority to regulate GHGs if they are found to endanger public health.
The Trump administration’s move to dismiss a lawsuit over xAI’s unpermitted natural gas turbines highlights the growing tension between AI-driven energy demand, environmental justice, and climate policy rollbacks.
A coalition of 24 states and 10 cities has filed a lawsuit against the EPA to block the repeal of the 2009 endangerment finding. The legal challenge seeks to restore the scientific foundation that allows the federal government to regulate greenhouse gas emissions under the Clean Air Act.
A coalition of 23 states and 14 cities has filed a lawsuit against the EPA to overturn the Trump administration's repeal of the 2009 endangerment finding. The legal challenge seeks to restore the scientific foundation that mandates federal regulation of greenhouse gas emissions under the Clean Air Act.
A coalition of U.S. states has filed a major lawsuit against the Environmental Protection Agency (EPA) following its decision to repeal the 2009 Endangerment Finding. The legal challenge seeks to preserve the scientific determination that greenhouse gases threaten public health, which serves as the mandatory legal trigger for federal climate regulations.
The Environmental Protection Agency's recent repeal of the 2009 Greenhouse Gas Endangerment Finding has sparked widespread public outcry and a wave of litigation. This move effectively dismantles the legal foundation for federal climate regulation, signaling a radical shift in U.S. environmental policy.
This page surfaces every story mentioning Clean Air Act across our climate coverage. We track each entity's appearance over time so readers can trace how the narrative evolves — which developments are isolated incidents, which build into longer arcs, and which reframe how operators in the space think about the entity. Story selection uses the same multi-source verification gate applied across the rest of our coverage.
Read our editorial methodology for how we identify, deduplicate, and score entity references. Our glossary defines the technical terms used across stories on this page, and our trends index contextualizes individual developments against the longer-running climate beat. Cross-entity comparisons live on our compare view.
Entities only appear on this page once the classifier scores them at a minimum 35 percent relevance to the story, filtering out passing mentions. According to that methodology, reviewed July 2026, this follows multi-source corroboration standards recommended by journalism research bodies such as the Reuters Institute for the Study of Journalism.
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| What you see | What it tells you |
|---|---|
| Story count | Number of distinct stories where Clean Air Act was a primary or referenced actor. |
| Recency clustering | Whether mentions are concentrated in a recent window (a news cycle) or distributed (a sustained arc). |
| Sentiment distribution | Aggregate sentiment of the stories mentioning this entity, weighted by impact score. |
| Cross-niche links | When the same entity surfaces in our sibling networks, we link to those views to enrich context. |