Stop CARB Act Strips States’ Power to Control Pollution from Construction and Farm Equipment

The Stop California from Advancing Regulatory Burden Act of 2025, or the Stop CARB Act, is a direct, two-pronged move to centralize control over engine emissions at the federal level. This legislation targets the ability of states to set stricter pollution standards than the federal government, specifically focusing on nonroad engines—think bulldozers, tractors, and other heavy equipment—and the standards for new passenger vehicles.

The End of State-Specific Engine Rules

Section 2 of this bill immediately pulls the rug out from under any state or local government trying to set their own emission standards for nonroad engines and vehicles. This is a massive shift. Historically, states like California could get a waiver under the Clean Air Act to enforce stricter standards, and other states often followed suit. This bill completely removes that authority, making federal rules the only rules for pollution coming from new construction and farm equipment, as well as locomotives. If your state had a waiver to keep the air cleaner—say, requiring newer, less-polluting engines on job sites—that waiver is instantly canceled and legally void. Any application for a new waiver that was pending? Automatically denied. For the folks working construction or farming, this means the regulatory landscape for their equipment just got simplified to one federal standard, but for anyone living near a port, a major construction zone, or heavy agricultural activity, it means the federal standard is now the ceiling, not the floor, for air quality.

Goodbye, California Effect

Section 3 takes aim at passenger vehicles by repealing Section 177 of the Clean Air Act. This is the provision that allowed states to voluntarily adopt California’s stricter new motor vehicle emission standards instead of the federal ones. This mechanism was key for states looking to tackle smog and improve air quality beyond the minimum federal requirements. By repealing Section 177, the option for states to follow California’s lead on cleaner cars and trucks is gone. While this creates a single, unified federal standard for manufacturers, potentially streamlining their production lines, it removes a critical tool for states facing severe air quality issues, especially those with dense populations or unique geographical challenges that trap pollution.

Centralization vs. Clean Air

The Stop CARB Act is essentially a high-stakes power grab, shifting significant environmental regulatory authority from state capitals straight to Washington D.C. The benefit here is clear for manufacturers: they now deal with one set of rules for nonroad engines and vehicles across all 50 states, which should reduce compliance costs and bureaucratic complexity. However, the cost is borne by states and the public health of their residents. By eliminating the ability to set stricter standards for heavy-duty, off-road equipment—which are major contributors to particulate matter and smog—states lose their ability to tailor environmental policy to local needs. If the federal standards are weaker than what states deem necessary, people living in areas with poor air quality could see a direct, negative impact on their health, as local authorities are now legally blocked from enforcing cleaner engine requirements.