Understanding the Endangerment Finding, Made Simple (with Benjamin DeAngelo)

Welcome back to Climatific, a free, weekly read that breaks down climate science so it makes sense- not for scientists or researchers, but for everyday people trying to understand the planet we live on, what’s happening to it, and why it matters.

If you’ve been paying attention to the news, there’s a good chance you’ve seen a headline or two about the recent rollback of the EPA’s 2009 endangerment finding. Or, maybe, right about now, you’re thinking, "What endangerment finding? Who’s endangered?”

You’ve got questions. We’ve got answers.

Join us for Climatific’s first-ever collaboration as we sit down Benjamin DeAngelo—a Penn State grad, Howard University adjunct professor, business founder, and, most important to this issue, the technical lead for the development of the endangerment finding seventeen years ago.

If you’re a new subscriber, catch up on past issues of Climatific and learn more about who we are here:

Benjamin DeAngelo has held many titles throughout his career, and they’ve pretty much always addressed climate change.

Benjamin worked for the federal government for 27 years bridging science and policy through senior positions at the EPA (the US Environmental Protection Agency), NOAA (the National Oceanic and Atmospheric Administration), and the White House Office of Science and Technology Policy.

He left the EPA in July 2025 and, since, founded a consulting business to provide climate mitigation and resilience strategies to the public and private sectors. He’s also an adjunct professor at Howard University and a senior advisor for two other consulting firms. He’s a Penn State grad, and currently resides in Washington D.C.

In other words, he’s kind of a big dill.

If you have more questions for Benjamin after this issue, you can find him on LinkedIn!

A bit of necessary context before we dive in:

The Clean Air Act, originally signed by President Lyndon B. Johnson in 1967 and amended by President Richard Nixon in 1970, is one of the biggest environmental laws in our nation’s history. It’s the reason we have vehicle emissions standards.

Its goal? To reduce and control air pollution.

It says that there are certain pollutants that we emit from our cars and factories that are harmful to human health and, since they’re harmful, the EPA should be able to regulate how much of these pollutants are legal to emit.

The endangerment finding added onto the Clean Air Act by saying that greenhouse gases should also be regulated pollutants because the science says that greenhouse gases are harmful to human health, too.

The reason the endangerment finding has been in the news is that, on February 12, 2026, the endangerment finding was rescinded. This means that the EPA cannot regulate greenhouse gases anymore under the Clean Air Act.

We’re here with Ben to find out why.

As Ben explains, any pollutant the EPA regulates has to have proof that it is bad for people and the environment.

In the endangerment finding, they found that greenhouse gases harm, or endanger, the American public. It’s what gave the EPA the authority to step in to reduce and control greenhouse gases (under the broader Clean Air Act umbrella).

What’s the Harm? Greenhouse gases are linked to several adverse health effects through their impact on climate change, including heat effects that can lead to premature death and sickness, exacerbated air quality that causes asthma, the spread of vector-borne diseases, and increased risk of hazards from wildfires, floods, and stronger storms.

Ben describes the two questions the researchers had to answer:

Also, Yes. Six of them from motor vehicles, to be exact (carbon dioxide, methane, and more).

Answering “yes” to both of these questions allowed the EPA to step in and start rolling out improvements to the efficiency of vehicles and the electricity sector at-large.

High Stakes. The team was using the Clean Air Act to regulate greenhouse gas emissions for the first time ever.

Ben says, “We knew full well that whatever we did would undergo a lot of scrutiny… There was no room for cutting corners.”

Which meant they had to be sure.

No Hyperboles. The researchers scanned thousands (yes, you read that right) of individual studies and baked all of that information into one big cake. They pulled their ingredients from scientific assessments that had already undergone academic and governmental review, all to credibly build the case for why GHGs should be regulated.

Because if they weren’t sure, or if they twisted the science, litigation was surely ahead.

And litigation there was! The DC Circuit Court of Appeals heard a case that doubted the team’s approach to marshaling and characterizing the science in the endangerment finding. The result? The EPA was “unambiguously correct.”

The science has changed, but not in a way that benefits the repeal of the endangerment finding.

It’s gotten stronger (says Ben, and also the prevailing body of scientific literature).

The initial presentation of the rollback of the endangerment finding was scientific, so Ben says he’s “not surprised people have that impression.”

Ben says that, really, lifting the endangerment finding is based more on legal arguments.

The current EPA is arguing that the Clean Air Act was never intended for the regulation of greenhouse gases, but rather the more “traditional” air pollutants that cause direct and local human health concerns. But these arguments circle back to the ones rejected by the Supreme Court when the endangerment finding was first circulated in 2009.

Every pollutant that the EPA regulates has its own costs and benefits analysis to not being regulated. These cover anything from compliance costs to consumer costs (like higher vehicle costs to meet standards). But then there’s also the cost savings- e.g., avoided maintenance costs, avoided fuel costs, etc.

And then there are the benefits, which are quantified through this metric called the social cost of carbon. The social cost of carbon is the “social cost of damage caused by emitting one ton of a greenhouse gas over time.” Let’s address that with a fresh brain another week, shall we?

What you need to know: choosing to not regulate a pollutant is not going to save us money. It’s good for our wallets and the environment to emit less.

Hear it from Ben: There is a very credible body of scientific evidence that we have and that is accumulating. The climate is changing rapidly, and we should really take it seriously, “for our own sake and for our children’s.”

We couldn’t have put a better bow on the conversation ourselves!

It’s back by popular demand! Join us next week for more discussion on electricity. We’ll talk about the grid’s shocking links to climate change and address its implications on our infrastructure and your electricity bill.

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