[co-author: Stephanie Kozol]*

California Attorney General (AG) Rob Bonta is leading a coalition of 22 Democratic states and the District of Columbia, to defend the Environmental Protection Agency’s (EPA) rule that sets stringent greenhouse gas emissions standards for heavy-duty vehicles. The coalition filed a motion to intervene in the U.S. Court of Appeals for the D.C. Circuit, where the EPA’s rule is facing a legal challenge from Republican AGs.

The EPA’s “Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles–Phase 3” rule, finalized in March, allegedly reduces emissions from heavy-duty vehicles such as freight trucks and buses. The Democratic AGs argue that these standards are crucial for mitigating the adverse effects of climate change and criteria pollution in their states.

The coalition’s motion to intervene states that if the petitioners prevail, allegedly harmful emissions threatening public health and the environment will increase, exacerbating climate change and public health harms. The coalition claims that the increased emissions would be long-lasting due to the longevity of greenhouse gases in the atmosphere and the longevity of higher-emitting vehicles sold under weakened standards.

The legal challenge to the EPA’s rule comes from a group of 24 Republican AGs led by Nebraska AG Mike Hilgers, who allege that the rule exceeds the agency’s statutory authority. Simultaneously, a separate coalition of 17 states and the Nebraska Trucking Association filed a lawsuit in the U.S. District Court for the Eastern District of California, seeking to block California’s Advanced Clean Fleets regulation.

Why It Matters

The outcome of this legal battle will have significant implications for the nation’s transportation sector. The case also highlights the ongoing tension between state-led environmental initiatives and the federal government’s regulation of emissions standards.

*Senior Government Relations Manager