Stop CARB Act Strips States of Power to Set Emission Standards for Construction and Farm Equipment

The aptly named Stop California from Advancing Regulatory Burden Act of 2025, or the Stop CARB Act, is a major power shift that takes control of specific emission standards away from state and local governments and centralizes it entirely at the federal level. This bill isn’t focused on your daily driver; it targets the heavy equipment that builds our roads and harvests our food: new nonroad engines and vehicles, including construction equipment, farm vehicles, and locomotives. The core action is simple: No state or local government can create or enforce any emission rule for these specific engines going forward (Sec. 2).

The End of State Innovation in Emissions

If you live in a state that has historically tried to tackle local air quality issues by setting stricter standards—think California, but also states that adopted their rules—this bill is a complete reset. Section 2 immediately cancels any special permission (waiver) that states previously received from the EPA to set stricter rules for nonroad engines. If your state had an application pending to tighten standards on, say, diesel construction equipment, that application is now automatically denied. For the manufacturers of this heavy machinery, this is a win for regulatory simplicity, as they only have to comply with one federal standard, regardless of which state they sell in.

But for people living near ports, rail yards, or large construction sites, this means your local government just lost its primary tool for mandating cleaner air from these heavy polluters. If the federal minimum standard isn't good enough for your community's air quality, there is now no legal path for your state or city to require something better. This effectively locks in the federal standard as the ceiling, not the floor, for emissions from these engine types, forcing communities with specific pollution problems to rely solely on federal action.

Taking the California Option Off the Table

Beyond the heavy equipment, the bill also makes a significant change to how regular vehicle emissions are managed across the country. Section 3 completely repeals Section 177 of the Clean Air Act. This is the provision that allowed other states to voluntarily adopt California’s stricter new motor vehicle emission standards. If a state wanted cleaner cars and trucks than the federal government required, they could simply opt into the California rules. By repealing Section 177, that option is gone.

Think of it this way: States that want to push for rapid adoption of zero-emission vehicles or simply cleaner internal combustion engines now lose a powerful tool they used to bypass potentially weaker federal standards. For residents in those states, the air quality standards for new vehicles will now be strictly dictated by federal regulation, removing the ability of state policy makers to respond to local environmental concerns by adopting a higher standard.

The Real-World Impact: Uniformity vs. Local Control

This legislation prioritizes regulatory uniformity for industry over the ability of states to address local environmental needs. On one hand, manufacturers of farm and construction equipment get regulatory certainty, which could theoretically lower compliance costs and simplify the supply chain. On the other hand, residents in areas with poor air quality—often urban centers or communities near industrial hubs—lose the ability to use state law to force cleaner technology adoption, particularly for nonroad engines that contribute significantly to regional air pollution.

In short, the Stop CARB Act centralizes power, removes regulatory flexibility, and ensures that when it comes to emissions from heavy equipment and the standards for new cars, the federal government gets the final, and only, say. This is a clear move to dismantle the ability of states to act as environmental policy leaders, which could have long-term consequences for public health in areas struggling to meet clean air goals.