ESG & Industry Updates

Clean Air Act, CARB Waivers & ACT in question under new EPA

Written by Kelly Burke | Mar 28, 2025 7:33:12 PM

Nationally, we are seeing a lot of change afoot on issues surrounding emissions and climate change, but at the state and regional levels we are largely seeing a continuation of standing policies. The following is a quick rundown of some of the news you may have been seeing about the attempt to overturn the Clean Air Act itself, or alternatively, to rescind EPA waivers in California - both of which could impact the Massachusetts’ Advanced Clean Trucks Rule, among other environmental policies.

The Clean Air Act is in the news the past few weeks, as EPA Director Zeldin announced they would look at overturning it entirely. Common sentiment seems to be that this is a hyperbolic stance the Trump Administration is using to pressure the agency to rescind both climate related policies in the Biden Admin’s Inflation Rection Act (refresher here: Inflation Reduction Act - Relevant Industry Item Snapshot ) and rescind the waivers granted to California that allow it to set its own emissions limits, which have as of late served to essentially unofficially dictate national policy on emissions by way of truck manufacturers.

So what are we really talking about?

For background - The Clean Air Act itself. In 1970, Congress granted the EPA the power to regulate emissions from stationary and mobile sources – meaning both vehicles/trucks/airplanes/equipment and power plants. The act requires EPA to set standardized air quality standards at a national level, based on the best available balance of scientific evidence and best available technology in mind. It was revised over time, most critically in the 1990s and is essentially the framework of how the US controls and combats air pollution. Under the Clean Air Act, the EPA sets allowable limits on specific chemicals and pollutants, and States or tribal governments are required to develop plans for compliance with those regulations at the local level.

States are required to have standards at least as strict as the national standards, and the EPA can approve more stringent than federal standard approaches by states (for example, California). That is a major thing we are seeing change with the current Administration, and the wider impacts of not allowing more stringent standards impacts multiple issues we are keeping an eye on in the industry.

EPA Waivers for CARB: California’s independent standards for emissions regulations on engines and heavy-duty vehicles hinge on EPA waivers granted to the California Air Resources Board (CARB). These waivers allow California to set more stringent guidelines for their state than the EPA has set for the country. This has been customary because of the size and population of the State and its uphill battle against air pollution and smog. However, the more contemporary waivers, specifically on heavy duty vehicles, have resulted in national ripple effects, namely to truck manufacturers and transportation companies that have left more questions than answers on implementation and compliance.

Two separate pieces of legislation have been introduced to Congress to revoke the waivers given to California by the EPA that allow it to have more stringent emissions requirements and prevent additional states from adopting those requirements as they choose. One bill seeks to achieve this by repealing the California Clean Air exemption, and removing the section of the prior ruling that allowed other states to adopt an EPA granted waiver policy for their state. The other bill seeks to revoke any waiver given to CA since January 2022, which would include the Advanced Clean Trucks & Omnibus Low Nox Rules.

Advanced Clean Truck Rule: If the CARB waivers are rescinded, then California no longer has the authority to impose the Heavy-Duty Omnibus and Advanced Clean Truck Rules. The ACT was also, as you know, adopted in Massachusetts and several other States (refresher here: CARB's Advanced Clean Truck Rule is Live in Massachusetts).

In theory, overturning means that the rule disappears entirely, but there is some question about which states have a separate legal basis for the law outside of the CARB waivers. In MA, for example, the law additionally rests on several laws regarding climate change (like this one: Deja Vu: MA Passes Landmark Climate Change Bill) so in theory to meet the goals of legally ratified laws in MA, the bill has to stand…. But it would be contrary to federal policy. So it becomes a pretty sticky legal question, and one that neither we nor anyone else seems to have a solid answer for at the moment. 

We are keeping an eye on these and other federal policy change issues that impact our industries, and will pass along what we learn as we learn it. Stay tuned!