In my 32-year career at EPA, which included 18 years as director of EPA’s Office of Transportation and Air Quality, I witnessed many historic moments, including reducing harmful emissions from diesel trucks, cars, and locomotives saving tens of thousands of premature deaths and finalizing the Obama Administration’s historic 2012 fuel efficiency standards. My time at EPA taught me that in the generational fight against climate change, a few truly pivotal moments can echo for decades. That day in 2009 was one of them. It reaffirmed EPA’s commitment to protecting our clean air and the health of future generations.

The Endangerment Finding is the backbone and legal foundation for nearly every climate regulation enacted at the federal and state levels, from clean car and truck standards to power plant emissions. But it’s even more than that. It’s a moral commitment to the health and well-being of present and future generations. It means fewer children with asthma. It means fewer premature deaths from polluted air. It means fewer hospitalizations. It means lives saved.

Yet today, it’s under threat. The new administration is again bowing to corporate demands for less regulation and weaker environmental safeguards – ultimately, prioritizing profits over our health and well-being. The $8 trillion global fossil fuel industry has its sights set on the Endangerment Finding. The finding has long faced opposition from fossil fuel interests and their political allies, who have made effort after effort to overturn it through every means available – from policy fiat to litigation. In 2013, they litigated the finding all the way to the Supreme Court. But they have always failed.

Today, the new administration is ready to try again. They want to make good on their desire to “re-evaluate” the finding and potentially reverse it. They argue that climate regulations are costly and unnecessary, effectively asking very American: “what’s the cost of your health or your life?”

One of the new administration’s first executive orders directed EPA to undertake a wholesale reevaluation of the nation’s climate policies. Buried in the wide-ranging order is a directive to the EPA administrator and other agency heads to “submit joint recommendations . . . on the legality and continuing applicability of the Administrator’s findings, ‘Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act…’”

As instructed, in late February, newly confirmed EPA Administrator Lee Zeldin complied by purportedly recommending to the White House that the agency repeal the Endangerment Finding. Sadly, that came one month after saying in his confirmation hearing that he would “enthusiastically uphold” EPA’s mission to protect human health and the environment.

The ramifications of that recommendation are profound. Without the Endangerment Finding, EPA would be unable to enforce key provisions of the Clean Air Act that target greenhouse gases. The Clean Car, Clean Truck, and power plant pollution rules would be scrapped, leaving America’s largest sources of greenhouse gases unregulated and threatening public health.

The new administration’s push to strip EPA’s regulatory powers would resonate beyond U.S. borders, where the global community is fighting to prevent irreversible climate damage. The United States is the world’s second largest greenhouse gas emitter; its climate policies significantly limit global efforts to cut emissions. A U.S. retreat from climate action would send a dangerous signal to other nations that may be on the fence about their own actions to mitigate climate change.

Defending the Endangerment Finding, and EPA’s decades of progress, requires a united front. Congress, California and other States that have adopted California clean car and truck programs, environmental groups, medical professionals, and business leaders must unite to oppose these threats. The business community in particular has already invested billions in clean energy transitions; dismantling the foundational regulations would cause economic chaos. Defending this landmark finding is not just about protecting the environment; it’s about securing your rights to your health and your family’s health.

We must also urge the courts to once again uphold the law and preserve the progress we’ve made. Fortunately, the scientific and legal underpinnings of the Endangerment Finding have only grown stronger with each passing year. It’s that strength that allowed it to withstand earlier attacks and legal challenges.

The science is unequivocal: climate change is real, and the Endangerment Finding is essential for acknowledging this reality and taking urgent action. If the new administration succeeds in repealing it, we risk losing the momentum built in the past decade to combat climate change – and yes, we put our health at risk.

Let’s put aside political posturing and corporate interests who get richer at the expense of public health. It’s time to unite and defend the Endangerment Finding. Our children, our planet, and our economy depend on it. Let’s stand up for science, for health, and for the health of our planet.