On Thursday 12 February 2026, President Donald Trump and Environmental Protection Agency (EPA) Administrator Lee Zeldin repealed the EPA’s 2009 greenhouse gas Endangerment Finding, calling it the “single largest deregulatory action in American history”. The final rule also scraps federal greenhouse gas standards for cars and trucks, with the administration claiming more than $1.3 trillion in savings and an average £1,900 ($2,400) reduction in vehicle costs. Environmental and public health groups immediately signalled court challenges. (epa.gov)

The Endangerment Finding has been the legal keystone for US climate action since it followed the Supreme Court’s Massachusetts v. EPA ruling in 2007, which confirmed greenhouse gases are air pollutants under the Clean Air Act. In December 2009, the EPA concluded six gases-including carbon dioxide and methane-endanger public health and welfare, enabling limits on emissions from vehicles and other sources. (supreme.justia.com)

Thursday’s repeal eliminates federal greenhouse gas standards for motor vehicles and engines, and removes “off‑cycle” credits such as start‑stop systems. That matters because transport is the largest source of US greenhouse gas emissions by sector, responsible for about 28% in 2022, led by cars, SUVs and freight trucks. (epa.gov)

The White House argues the rollback will make vehicles more affordable and reduce compliance burdens for industry. Health organisations counter that weaker standards mean more soot and smog, with higher risks of respiratory and cardiovascular disease. The American Lung Association said it will challenge the repeal, warning of increased pollution and preventable illness if vehicle climate protections are withdrawn. (epa.gov)

Independent analyses also forecast large social costs if greenhouse gas controls on vehicles are dismantled. An Environmental Defense Fund filing on the proposal projected, by 2055, as many as 77,000 additional early deaths and 52 million more asthma attacks from increased pollution, alongside up to $4.7 trillion in net harms and as much as $1.7 trillion in extra fuel spending. The administration disputes those totals, but has not provided comparable quantified public‑health benefits from the repeal. (edf.org)

Legally, the fight will centre on how courts weigh science and statutory authority after recent Supreme Court decisions that narrowed agency power. West Virginia v. EPA restricted broad carbon rules for power plants in 2022, and Loper Bright (June 2024) ended Chevron deference, instructing judges not to default to agency interpretations of ambiguous laws. Expect challengers to argue the Clean Air Act still compels EPA to act on climate risk, while the administration points to those rulings to defend its retreat. (law.cornell.edu)

A separate twist: the science the EPA leaned on. A federal judge ruled last month that the Department of Energy unlawfully convened a hand‑picked Climate Working Group whose report was used to justify the repeal-violating the Federal Advisory Committee Act’s transparency rules. The court did not strike the report itself, but the finding undercuts the credibility of the process and may weigh on judicial review. (cen.acs.org)

Repeal also reopens an old courtroom door. In 2011, the Supreme Court held that the Clean Air Act and EPA action displaced federal common‑law “public nuisance” lawsuits over carbon pollution. With EPA stepping back, legal scholars say a ‘new front’ of nuisance litigation against major emitters could return-particularly in state courts. (supreme.justia.com)

There’s a competitiveness angle too. Major export markets are maintaining steep vehicle CO₂ cuts this decade and a 100% reduction target for new cars by 2035, even as Brussels adds short‑term flexibilities. If US standards stall while others ratchet up, American models risk falling behind on efficiency and emissions features required overseas. (climate.ec.europa.eu)

States are already mobilising. California’s attorney general vowed to sue, arguing the repeal violates Supreme Court precedent and decades of science. Expect a multistate coalition to press for an immediate stay while courts assess whether EPA can discard a finding repeatedly upheld by federal judges. (oag.ca.gov)

What happens next for emissions? Even without EPA’s greenhouse gas standards, the Department of Transportation’s fuel‑economy rules under separate law continue to exist, and states can still pursue clean‑air strategies on pollutants like soot and nitrogen oxides. For fleets and cities, practical steps-tightening anti‑idling enforcement, accelerating electric buses and municipal vehicles, and prioritising clean construction equipment-can lock in fuel savings and health gains while litigation unfolds. (mondaq.com)

For households and businesses trying to plan, the signal is mixed-but action is still possible. Choosing higher‑efficiency or zero‑emission models reduces exposure to volatile fuel costs; employers can back cleaner commuting through charging, secure bike parking and transit benefits; and communities can push for local air‑monitoring and heat‑health programmes. The policy ground has shifted in Washington, but on‑the‑ground choices still cut emissions and protect health today.