Consortium Statement on the EPA’s Proposed Delay of Tier 4 Vehicle Emissions Standards

May 15, 2026

Contact: Savannah Martincic, Manager of Communication, The Medical Society Consortium on Climate and Health smartincic@ms2ch.org

The Environmental Protection Agency has released its proposed two-year delay of vehicle emission standards for ozone-forming pollutants and particle pollution. Below is a statement from the Medical Society Consortium on Climate and Health, which represents 58 medical societies and 30 state clinician networks working to advance climate solutions through a health and equity lens: 

Clean air is a uniting issue. Americans across the political spectrum want to breathe air that does not make them sick. They want their children to grow up with healthy lungs. They want healthcare costs to go down, not up. The Tier 4 vehicle emissions standards, now proposed for delay by the EPA, would have delivered on all three. Which raises a question this administration has yet to answer: who is served by rolling back clean air protections? 

It does not serve patients. Nearly half of all children in the United States are already growing up breathing unhealthy air. Tailpipe pollution from cars and trucks drives asthma attacks, heart disease, preterm birth, and impaired lung development in children. These harms are well-established, well-documented, and entirely preventable. Delaying stronger standards for two more years means two more model years of vehicles rolling off assembly lines without protections that the technology can already deliver.  

It does not serve taxpayers. The Environmental Defense Fund estimates that full repeal of the Tier 4 standards would result in more than $140 billion in health costs through 2055. A two-year delay adds tens of billions more in emergency room visits, hospitalizations, lost workdays, and chronic disease management costs that fall on families, employers, and public health systems. This administration speaks frequently about reducing the burden on American families. Allowing preventable illness to accumulate is not a path toward that goal.  

It does not serve the broader economy. The technology required to meet these standards is not emerging or experimental. Gasoline particulate filters are already installed on dozens of 2026 vehicle models and roughly one quarter of current vehicle lines test below the new light-duty standard.  

What this delay does serve is a pattern. In the past several months, this administration has rolled back Clean Air Act protections for industrial facilities, proposed repealing mercury standards that protect children’s neurological development, and eliminated greenhouse gas standards for power plants. Each action has been framed as relieving regulatory burden. Each action shifts that burden instead onto the bodies of the people least able to absorb it: children, the elderly, pregnant women, and the communities that have always lived closest to the sources of pollution. 

We urge the EPA to withdraw this proposal and stop dismantling protections that were built on decades of science, are supported by broad public consensus, and play a critical role in making American air safe to breathe.   

The views expressed here are of the Medical Society Consortium on Climate and Health and not necessarily of its medical society members.