A federal court in California has issued a preliminary injunction against the California Air Resources Board’s efforts to enforce the Clean Truck Partnership agreement against four major truck manufacturers. This decision means that, at least while this case is pending, CARB may not impose its requirements for the Advanced Clean Trucks rule, the Omnibus NOx rule, the Heavy-Duty On-Board Diagnostics rule, the Advanced Clean Fleets rule, or the Phase 2 California GHG Emissions requirements on OEMs selling trucks in the California market.

The OEMs had sued CARB to clarify the legal obligations for compliance with emissions laws. In June, Congress had rescinded the EPA waivers that allowed CARB to impose the ACT and NOx rules, but CARB claims those recissions were illegal because the Congressional Review Act does not apply to waivers. CARB also filed suit in federal court to challenge those waivers, and that case is also pending.

In addition, the OEMs claimed that CARB was attempting to enforce the Heavy-Duty On-Board Diagnostics rule, the Advanced Clean Fleets rule, or the Phase 2 California GHG Emissions requirements even though CARB never obtained a waiver from EPA for any of these requirements.

CARB sought to enforce those requirements through the Clean Truck Partnership agreement with the OEMs. In that agreement, the OEMs agreed to comply with the California emissions requirements, even if a court held that CARB did not have authority to impose those rules. In exchange, the OEMs got an additional two years before compliance was required, and certain other concessions.

On October 27, CARB filed suit in Alameda County Superior Court (a state court) to enforce the terms of the CTP agreement against the OEMs.

The federal government has taken the position that all of the CARB requirements are invalid and has directed the OEMs not to comply. The OEMs have asked the federal court to clarify their legal obligations for compliance.

In granting the preliminary injunction, the federal court held that the OEMs were likely to succeed on the merits and would suffer irreparable injury if the injunction was not granted. CARB had previously informed the OEMs in August that CARB-certification was not necessary, and manufacturers could sell EPA-certified engines and vehicles in California. Thus, CARB argued, the OEMs had suffered no injury.

But the court ruled that the state court lawsuit to enforce the terms of the CTP agreement constituted irreparable injury for the manufacturers because CARB had threatened sanctions against the OEMs for noncompliance. As a result, the court granted a preliminary injunction based on the OEMs’ claim that the Clean Truck Partnership violates the Clean Air Act and the Supremacy Clause of the U.S. Constitution.