The U.S. Environmental Protection Agency (EPA) on Thursday committed “the single largest deregulatory action in U.S. history,” as EPA Administrator Lee Zeldin described it, by eliminating an Obama-era verdict against carbon dioxide and other greenhouse gases. The 2009 Endangerment Finding functioned as the bottommost block in the Left’s Jenga tower of climate regulation, and the Trump administration hopes to save U.S. taxpayers more than $1.3 trillion by knocking it clear.

“The Trump EPA is strictly following the letter of the law,” Zeldin proclaimed, “returning commonsense to policy, delivering consumer choice to Americans, and advancing the American Dream.”

America’s two-decade mistake of treating carbon dioxide as a dangerous pollutant began during the Bush administration, when left-wing activists and progressive-leaning states sued the administration for not regulating carbon dioxide under the Clean Air Act of 1963.

On April 2, 2007, the Supreme Court handed down its decision in Massachusetts v. EPA, in which a 5-4 liberal majority determined that carbon dioxide was a pollutant under the Clean Air Act, finding that its definition includes “any physical, chemical … substance or matter which is emitted into or otherwise enters the ambient air” and “embraces all airborne compounds of whatever stripe.” It directed the EPA to study whether carbon dioxide was worthy of regulation.

Of course, carbon dioxide is not a pollutant under any common understanding of the word. A pollutant is a substance that contaminates the surrounding environment with something foreign or harmful — like an oil spill or the harmful compounds that cause acid rain. Carbon dioxide, however, is the primary product of human (and animal) respiration and the primary input to the photosynthesis of plants.

Along with water vapor (H2O), carbon dioxide (CO2) is produced in any combustion reaction involving hydrocarbon-based (CHX) fuels and oxygen gas (O2) — whether in a simple fire or in cellular energy production. It is therefore the natural byproduct of any carbon-based form of energy production, whether by wood, charcoal, coal, natural gas, oil, or some other product.

However, on December 7, 2009, Obama administration EPA Administrator Lisa Jackson found that atmospheric carbon dioxide (and five other gaseous compounds) “threaten[ed] the public health and welfare of current and future generations.”

This finding “led to trillions of dollars in regulations that strangled entire sectors of the United States economy, including the American auto industry,” Zeldin lamented. “The Obama and Biden administrations used it to steamroll into existence a left-wing wish list of costly climate policies, electric vehicle mandates and other requirements that assaulted consumer choice and affordability.” Since then, the U.S. government has spent hundreds of billions of dollars propping up green energy projects that were not ready for economic prime time, leading to widespread blackouts and lost investment in impractical electric vehicles. At the same time, the endangerment finding has been used to rachet up the fuel efficiency requirements on cars, making those cars more expensive in the process.

However, the EPA cited two more recent Supreme Court decisions that it said justified its decision to rethink the law. The first was West Virginia v. EPA (2022), which struck down a Biden-era carbon tax scheme based on the Endangerment Finding on the ground that such “major questions” of policy should be decided by Congress, not an agency. In 2024, the Supreme Court issued Loper Bright Enterprises v. Raimondo, which overruled the infamous Chevron test and reframed the level of deference due to agencies in rulemaking.

Following these decisions, President Trump issued a day-one executive order, “Unleashing American Energy.” In the order, Trump authorized an “immediate review of all agency actions that potentially burden the development of domestic energy resources,” which would include the 2009 Endangerment Finding.

The EPA’s decision came after an extended public comment period of 52 days, four days of virtual public hearings with testimony from more than 600 individuals, and approximately 572,000 public comments on the proposed rule. The extent of the feedback illustrates the magnitude of its consequences for American energy and business.

As a result of that review, the EPA concluded that the Clean Air Act “does not provide statutory authority for EPA to prescribe motor vehicle and engine emission standards in the manner previously utilized,” and therefore “the 2009 Endangerment Finding made by the Obama Administration exceeded the agency’s authority to combat ‘air pollution’ that harms public health and welfare, and that a policy decision of this magnitude, which carries sweeping economic and policy consequences, lies solely with Congress.”

Notably, the EPA ran “the same types of models utilized by the previous administrations and climate change zealots” and found that, “even if the U.S. were to eliminate all GHG emissions from all vehicles, there would be no material impact on global climate indicators through 2100.” The only effect such auto emissions standards would have is to make life more difficult for American consumers.

President Trump was present at the White House press conference announcing the EPA’s decision. “We are officially terminating the so-called endangerment finding, a disastrous Obama-era policy that severely damaged the American auto industry and massively drove up prices for American consumers,” he said. “This determination had no basis in fact — none whatsoever. And it had no basis in law. On the contrary, over the generations, fossil fuels have saved millions of lives and lifted billions of people out of poverty all over the world.”

Naturally, the left-wing response to the announcement was furious. NBC News memorialized the 2009 Endangerment Finding as “the legal finding that it [the EPA] has relied on for nearly two decades to limit the heat-trapping pollution that spews from vehicle tailpipes, oil refineries, and factories.” Unmentioned was the way that carbon dioxide also “spews” from human lungs with every exhalation, or the way that its “heat-trapping” quality prevents the earth from turning into the dark side of Mercury at night.

Of more substantial impact, major environmental groups have promised to challenge the decision’s legality. The Trump administration would likely have to ask the Supreme Court to overturn Massachusetts v. EPA.

In the meantime, however, the Trump administration has smashed the rule “referred to by some as the ‘Holy Grail’ of the ‘climate change religion,’” as Zeldin put it. It “didn’t just regulate emissions, it regulated and targeted the American dream,” he said. Even more fundamentally, the Trump administration has exonerated the essential, natural compound of carbon dioxide. As Interior Secretary Doug Burgum weighed in, “CO2 was never a pollutant.” And it should never have been regulated as one.