As the Trump administration moves to weaken U.S. air pollution regulations, it is rolling out new legal interpretations aimed at tying the hands of future administrations for years to come.
In practice, this change limits the Environmental Protection Agency’s authority under the Clean Air Act. This result allowed EPA officials to ignore science, data, and the negative impact of their decisions on public health and the environment.
However, the new interpretation is designed to apply not only to the rules originally laid down, but also in the future.
If the U.S. Supreme Court affirms these interpretations in the inevitable legal challenges, it could make it difficult for future administrations to restore public health protections that the Trump administration has dismantled. It may also be difficult to update rules to respond to new information about health risks.
Typically, efforts to weaken pollution regulations through new legal interpretations are likely to be overturned in court. However, the EPA’s new interpretation is strategically designed to appeal to the current U.S. Supreme Court position regarding federal agency powers, especially in light of the Supreme Court’s 2024 decision in Roper Bright v. Raimondo. In this case, the court overturned the so-called Chevron doctrine. A 1984 Supreme Court ruling established that when a legal provision is ambiguous or a gap remains, courts should defer to the administrative agency’s legal interpretation of the competent statute. That respect 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 EPA from fulfilling its primary role of protecting public health and the environment alarming. Here are two examples of how the new interpretation unfolds.
Block future climate regulation
In February 2026, the EPA rescinded its 2009 endangered status finding, a determination under the Clean Air Act that carbon dioxide and five other greenhouse gases “could reasonably be expected to endanger the public health or welfare” because they contribute to climate change.
This endangered discovery provided the scientific and legal basis for an EPA rule requiring automakers, power plants, and oil and gas operations to reduce greenhouse gas emissions. Eliminating this would make it easier for the Trump administration to repeal greenhouse gas regulations.
Rather than attempt to challenge the science of climate change, which would be difficult given the growing mountain of evidence, the Trump EPA relied on legal arguments aimed at permanently nullifying the agency’s ability to regulate greenhouse gas pollutants under the Clean Air Act.
President Donald Trump and U.S. Environmental Protection Agency Administrator Lee Zeldin arrive at a White House event announcing the reversal of the 2009 Endangerment Study on February 12, 2026.
Anna Moneymaker/Getty Images
Among the administration’s many claims, two stand out:
First, the Trump Environmental Protection Agency says the Clean Air Act should be interpreted to limit the agency’s authority to regulate air pollution only when harm to the public is “resulting from local or regional exposure.”
That means the contribution of U.S. sources to global air pollution, no matter how demonstrable it is or how much it puts Americans at risk, is not subject to the Clean Air Act.
Second, the Trump EPA says reducing greenhouse gas emissions from cars and engines is “wasteful.” The paper points to global climate modeling that suggests these reductions will not significantly reduce harm to public health and welfare.
What is not mentioned in this discussion is that the actions of people around the world to reduce emissions across a variety of sectors add up. Vehicle emissions are the largest source of emissions in the United States. If the sector is too small to regulate, then nothing is big enough.
Both of these interpretations run counter to the EPA’s position on the original endangered finding, which the D.C. Circuit Court of Appeals upheld in 2012.
allow more toxic air pollutants
A second example includes the EPA’s March 17, 2026 proposal to ease pollution regulations for companies that use ethylene oxide, a known carcinogen, to sterilize medical devices.
In this proposal, EPA also changes its legal interpretation in a way that would, in turn, limit EPA’s ability to protect human health in the future from emissions of toxic air pollutants.
Under Section 112 of the Clean Air Act, EPA establishes a systematic program for regulating industries that emit significant amounts of air pollutants that can cause cancer, birth defects, genetic mutations and neurological harm, or adversely affect reproductive health.
EPA reviews how facilities control emissions and sets standards that require all facilities to meet standards for best-controlled sources. However, there is an important provision in section 112 called “residual risk” review. Eight years after EPA set its first technology-based standard, it must determine whether the public health risks posed by emissions from facilities after additional regulations are acceptable.
In 2024, the EPA updated hazardous air pollution rules for facilities that use ethylene oxide to sterilize medical equipment sensitive to steam heat, such as equipment containing plastics, rubber, and electronic components. Recent studies have shown that ethylene oxide poses a much higher cancer risk than previously thought, prompting the EPA to also update its 2006 residual risk findings and require additional safeguards.
The Trump EPA now insists the agency can only assess residual risks once, even if more recent information shows the health risks are unacceptably high.
By limiting its own authority, the EPA is withholding standards that would protect thousands of people from higher cancer risks. It also creates legal precedents that justify weakening other standards. These include standards for chemical manufacturing facilities that the Biden EPA updated in 2024 through a review of residual risks.
This precedent also prohibits the EPA from considering new information about the health effects of regulated hazardous air pollutants from all types of industries that the agency regulates under Section 112 of the Clean Air Act, such as oil refineries, chemical manufacturing, and paper mills.
discuss the law
These rules are just two examples of the government’s “if you don’t have the facts, say the law” approach.
If the administration’s strategy works, Americans may live and die by the influence of these industry-friendly regulations for years to come.
