As the Trump administration moves to weaken America’s air pollution rules, it is deploying new legal interpretations that are intended to tie the hands of future administrations for years to come.
In practice, the changes limit the Environmental Protection Agency’s authority under the Clean Air Act. The result allows EPA officials to ignore science, data and the adverse effects their decisions will have on public health and the environment.
But the new interpretations are also designed to apply not just to the rule in which they are first set forth but into the future.
If affirmed by the U.S. Supreme Court in inevitable legal challenges, these interpretations could make it harder for future administrations to restore the public health protections that the Trump administration eliminates. They could also make it difficult to update rules to respond to new information about health risks.
Typically, moves to weaken pollution regulations through novel legal interpretations would have a good chance of being overturned in court. But the EPA’s new interpretations are strategically designed to appeal to the current U.S. Supreme Court’s view of federal agencies’ authority, especially in light of the court’s 2024 ruling in Loper Bright v. Raimondo. In that case, the court overturned what’s known as the Chevron doctrine. A 1984 Supreme Court ruling had established that courts should defer to executive agencies’ legal interpretations of their governing statutes when the text of the law was ambiguous or left gaps. That deference no longer applies.
As a former EPA appointee who helped write and review dozens of regulations under the Clean Air Act during the Obama and Biden administrations, I find these efforts to prevent the EPA from doing its job of protecting public health and the environment to be alarming. Here are two examples of how the new interpretations are playing out.
Blocking future climate regulations
In February 2026, the EPA rescinded its 2009 endangerment finding, a determination under the Clean Air Act that carbon dioxide and five other greenhouse gases “may reasonably be anticipated to endanger public health or welfare” because they contribute to climate change.
The endangerment finding was the scientific and legal basis for EPA rules requiring automakers, power plants and oil and gas operations to cut their greenhouse gas emissions. Erasing it would make it easier for the Trump administration to eliminate greenhouse gas regulations.
Rather than try to challenge the science of climate change, which would be difficult given the growing mountain of evidence, the Trump EPA relied on legal arguments that were intended to dispense forever with the EPA’s ability to regulate greenhouse gas pollutants under the Clean Air Act.
Anna Moneymaker/Getty Images
Among the administration’s numerous arguments, two stand out:
First, the Trump EPA says the Clean Air Act should be read to limit the EPA’s authority to regulate air pollution only if its harm to the public is “through local or regional exposure.”
That would mean contributions from U.S. sources to global air pollution, no matter how demonstrable or how much they endanger Americans, are not covered by the Clean Air Act.
Second, the Trump EPA says that reducing greenhouse gas emissions from motor vehicles and engines would be “futile.” It points to global climate modeling that suggest these reductions would not meaningfully reduce the harm to public health and welfare.
What that argument fails to mention is that actions by people around the world to reduce emissions across different sectors add up. Motor vehicle emissions are the No. 1 contributor of U.S. emissions. If this sector is too small to regulate, then nothing is big enough.
Each of these interpretations is contrary to positions that the EPA took in the original endangerment finding, which the D.C. Circuit Court of Appeals upheld in 2012.
Allowing more toxic air pollutants
A second example involves the EPA’s proposal on March 17, 2026, to weaken pollution restrictions on businesses that sterilize medical equipment using ethylene oxide, a known carcinogen.
In that proposal, the EPA is also changing a legal interpretation in a way that would constrain the agency’s ability to protect human health into the future, this time from emissions of toxic air pollutants.
The Clean Air Act, under Section 112, establishes a methodical program for the EPA to regulate industries that emit significant quantities of air pollutants that can cause cancer, birth defects, genetic mutations or neurological harm, or harm reproductive health.
The EPA reviews how facilities control their emissions and sets standards that require all facilities to meet what the best-controlled sources are doing. But Section 112 has an important provision called “residual risk” review: Eight years after the EPA sets the first technology-based standards, it must determine whether the public health risk posed by emissions from the facilities after controls are added is acceptable.
In 2024, the EPA updated its hazardous air pollution rule for facilities that use ethylene oxide to sterilize medical equipment sensitive to steam heat, such as devices containing plastic, rubber or electronic components. Because recent research showed that ethylene oxide posed a much higher risk of cancer than previously thought, the EPA also updated its 2006 residual risk finding and required additional safeguards.
The Trump EPA is now arguing that the agency can assess residual risk only once, even if more recent information shows that the health risk is unacceptably high.
By constraining its own authority, the EPA is withholding standards that would protect thousands of people from a higher risk of cancer. It is also creating a legal precedent that will justify weakening other standards. Those include standards for chemical manufacturing facilities that the Biden EPA updated in 2024 through residual risk review.
That precedent would also prohibit the EPA in the future from taking into account new information about the health effects of any regulated hazardous air pollutant from any type of industry the EPA regulates under Section 112 of the Clean Air Act, including petroleum refineries, chemical manufacturing and paper mills.
Arguing the law
These rules are just two examples of the administration’s “if you don’t have the facts, argue the law” approach.
If the administration’s strategy works, the American public may be living, and dying, with the consequences of these industry-friendly regulations for years to come.
